EHP Library Malaria Bulletin 50 - November 27-December 13, 2002

 

 Social Sciences and Malaria Control
 

Afr J of Medicine and Medical Sciences (2001), 30, suppl:

 

         Wires, Webs and MIMcom.net. Julia Royal and Elliot Siegol (59-63).

         Malaria case managment at the community level in Gezira, Sudan. AA Adbel-Hameed (43-46).

         Household expenditure on malaria case management in Wad-Medani, Sudan. AA Abdel-Hameed, MNA Abdalla an dAH Alnaury (35-38).

         Urban malaria treatment behaviour in the context of low levels of malaria transmission in Lagos, Nigeria. WR Brieger et al. (7-15).

 
Bull World Health Organ 2002;80(10):817-21 
 
A public-private partnership for malaria control: lessons from the Malarone
Donation Programme.
 
Oyediran AB, Ddumba EM, Ochola SA, Lucas AO, Koporc K, Dowdle WR.
 
Malarone Donation Programme Africa, Nairobi, Kenya.
 
In 1996, Glaxo Wellcome offered to donate up to a million treatment courses
annually of Malarone, a new antimalarial, with a view to reducing the global
burden of malaria. The Malarone Donation Programme (MDP) was established the
following year. Eight pilot sites were selected in Kenya and Uganda to develop
and evaluate an effective, locally sustainable donation strategy that ensured
controlled and appropriate use of Malarone. The pilot programme targeted
individuals who had acute uncomplicated Plasmodium falciparum malaria that had
not responded to first-line treatments with chloroquine or
sulfadoxine-pyrimethamine. Of the 161 079 patients clinically diagnosed at the
pilot sites as having malaria, 1101 (0.68%) met all the conditions for
participation and received directly observed treatment with Malarone. MDP had a
positive effect at the pilot sites by improving the diagnosis and management of
malaria. However, the provision of Malarone as a second-line drug at the
district hospital level was not an efficient and effective use of resources. The
number of deaths among children and adults ineligible for MDP at the pilot sites
suggested that high priority should be given to meeting the challenges of
malaria treatment at the community level.
 
Health Policy 2003 Jan;63(1):17-36 
 
The economic impact of malaria in Africa: a critical review of the evidence.
 
Chima RI, Goodman CA, Mills A.
 
Department of Economics, University of Nigeria, Enugu State, Nsukka, Nigeria
 
Information on the economic burden of malaria in Africa is needed to target
interventions efficiently and equitably, and to justify investment in research
and control. A standard method of estimation has been to sum the direct costs of
expenditure on prevention and treatment, and the indirect costs of productive
labour time lost. This paper discusses the many problems in using such data to
reflect the burden to society or the potential benefits from control. Studies
have generally focussed on febrile illness, overestimating the burden of
uncomplicated malaria, but underestimating the costs of severe illness, other
debilitating manifestations, and mortality. Many use weak data to calculate
indirect costs, which fail to account for seasonal variations, the difference
between the average and marginal product of labour, and the ways households and
firms 'cope' in response to illness episodes. Perhaps most importantly, the
costs of coping mechanisms in response to the risk of disease are excluded,
although they may significantly affect productive strategies and economic
growth. Future work should be rooted in a sound understanding of the health
burden of malaria and the organisation of economic activities, and address the
impact on the productive environment, and epidemiological and socio-economic
geographical variation.
 
Trop Med Int Health 2002 Dec;7(12):1003-8 
 
Effect of community-wide use of insecticide-treated nets for 3-4 years on
malarial morbidity in Tanzania.
 
Maxwell CA, Msuya E, Sudi M, Njunwa KJ, Carneiro IA, Curtis CF.
 
London School of Hygiene & Tropical Medicine, London, UK Ubwari Field Station of
the Tanzanian National Institute of Medical Research, Muheza, Tanga, Tanzania.
 
OBJECTIVES: To investigate (1) benefits due to personal protection of individual
net users vs. mass killing of mosquitoes within villages as a result of
widespread net usage; (2) sustainability over several years of benefits against
malarial morbidity of insecticide-treated nets; (3) distribution of the benefits
in different age groups of children and (4) whether, as a result of fading
immunity, older age groups 'paid for' the benefits which they had enjoyed when
younger. METHODS: (1) Tabulation of earlier data to compare personal and
community-wide effects against mosquito vectors; (2) two cross-sectional surveys
for malaria parasitaemia, malarial fever, anaemia and splenomegaly in children
in eight Tanzanian villages, in which there had been community-wide use of
bednets which had been annually re-treated with alphacypermethrin for 3-4 years;
(3) comparison between children of different age groups and with intact, torn or
no nets in these villages and in 4-6 villages without nets. RESULTS: A 90-95%
reduction in infective bites outside nets in netted villages and an additional
54-82% reduction of bites among individual net users. Highly significant
reductions (by 55-75%) in malarial morbidity for children aged 6 months to 2
years were found in netted villages with, for some outcomes, better results
among individuals who themselves had intact treated nets. For older children,
benefits were less clear or absent, but there was no sign that the benefits
early in life were 'paid for' by worse outcomes in the netted villages later in
childhood. CONCLUSIONS: The overall benefits to the community of widespread use
of treated nets are sustainable and are not reversed in 3-4 years as a result of
fading immunity. It is important to ensure high enough coverage to realize the
full potential of the treated net method. By showing an impact on the vector
population in the community these results provide a strong argument for
organized free provision of net treatment, rather than relying on marketing.
 
 PubMed

 

Trans R Soc Trop Med Hyg 2002 Sep-Oct;96(5):560-4 
 
Seroprevalence of antibodies to repetitive domains of Plasmodium vivax
circumsporozoite protein in United Arab Emirates children.
 
Abu-Zeid YA, Alwash R, Shaheen HM, Bin-Othman SA, Lukic ML, Amiri KM, Charoenvit
Y.
 
Department of Biology, Faculty of Sciences, United Arab Emirates University, Al
Ain, United Arab Emirates. Email: [email protected]
 
The aim of this study was to determine the exposure of child citizens of the
United Arab Emirates (UAE) to Plasmodium vivax, and to elucidate if it was
related to place of residence or previous international travel to
malaria-endemic areas. Blood samples were collected from 1010 primary
schoolchildren resident in 7 out of 9 districts of the UAE during October and
November 1999. Plasma samples were tested for antibodies against MAP4
(DGQPAGDR)3P2P30, a multiple antigen peptide containing the repeat amino acid
sequences of P. vivax circumsporozoite protein (CSP), conjugated to 2 T-helper
epitopes, P2 (QYIKANSKFIGITE) and P30 (FNNFTVSFWLRVPKVSASHLE) from tetanus
toxin. For confirmation of P. vivax-specific reactivity, positive samples were
further tested against (AGDR)6, a synthetic peptide containing 6 copies of a
protective epitope within the CSP, and against a recombinant CSP, designated as
NS1(81)V20. Results indicated that 3.3% of the children were seropositive. The
seropositivity rates differed significantly in relation to place of residence,
whereas travel outside the UAE did not significantly affect the exposure rates
to P. vivax.
 
Trans R Soc Trop Med Hyg 2002 Sep-Oct;96(5):551-6 
 
Role of the pfcrt codon 76 mutation as a molecular marker for population-based
surveillance of chloroquine (CQ)-resistant Plasmodium falciparum malaria in
Ugandan sentinel sites with high CQ resistance.
 
Talisuna AO, Kyosiimire-Lugemwa J, Langi P, Mutabingwa TK, Watkins W, Van Marck
E, Egwang T, D'Alessandro U.
 
Ministry of Health, P.O. Box 7272, Kampala, Uganda. 
Email: [email protected]
 
The mutant genotype at codon 76 of the pfcrt gene (T76) has been proposed as a
molecular marker for surveillance of chloroquine (CQ)-resistant Plasmodium
falciparum malaria but this proposal has not been validated by population-based
surveys. In 1998-99, in 6 Ugandan sentinel sites, the prevalence of P.
falciparum infections with the T76 genotype and the level of CQ use were
measured by community surveys, and CQ resistance was determined by in-vivo tests
on 6-59-month-old children with clinical malaria. The prevalence of T76 was not
related to the overall clinical (early and late treatment failure: ETF + LTF; r
= 0.14, P = 0.78) or parasitological (RI + RII + RIII; r = 0.17, P = 0.73) CQ
resistance. However, the percentage of individuals carrying only infections with
the T76 genotype (T76 alone) increased with increasing ETF (r = 0.76, P = 0.07)
and type RIII parasitological failure (r = 0.69, P = 0.12). Similarly, the ratio
between T76 and K76 (the wild type) prevalences (T76/K76) was strongly and
positively correlated with ETF (r = 0.85, P = 0.03) and RIII (r = 0.82, P =
0.04). Moreover, T76 alone (r = 0.90, P = 0.01) as well as T76/K76 (r = 0.90, P
= 0.01) significantly increased with increasing community CQ use. T76 alone and
T76/K76 can be useful markers to estimate the ETF and RIII prevalence as well as
the amount of CQ use in the community.
 
Trans R Soc Trop Med Hyg 2002 Sep-Oct;96(5):499-506 
 
Risk of malaria attacks in Gambian children is greater away from malaria
vector breeding sites.
 
Clarke SE, Bogh C, Brown RC, Walraven GE, Thomas CJ, Lindsay SW.
 
Danish Bilharziasis Laboratory, Jaegersborg Alle 1D, DK-2920 Charlottenlund,
Denmark. Email: [email protected]
 
The causes of local variation in the prevalence of malaria were investigated in
rural Gambia. Cross-sectional prevalence surveys were carried out among 1184
young children (aged 6 months-5 years) in 48 villages, at the end of the
transmission season in 1996. Villages were categorized according to distance
from the nearest vector breeding sites, and the patterns of malaria
transmission, infection and disease compared. Children living in villages within
3 km of breeding sites experienced more infective bites, and higher prevalences
of parasitaemia and spleen enlargement than less-exposed children living further
away. Clinical illness, in contrast, was more common among infected children who
were less exposed. Infected children living 3 km or more from breeding sites
were more likely to have high-density parasitaemia (odds ratio [OR] = 1.98),
fever (OR = 2.60) and high-density parasitaemia together with fever (OR = 3.17).
Clinical attacks did not decline in older children, as seen amongst children who
were more exposed. These findings show that significant differences in the risk
of infection and clinical attacks can occur over very short distances. The age
at which protective immunity is acquired may be delayed in villages where
transmission intensity is lower, thus increasing the risk of a clinical attack
following infection. Communities with the lowest vector densities may be those
at greatest risk of disease.
 
Trans R Soc Trop Med Hyg 2002 Sep-Oct;96(5):481-2 
 
Malaria during a multinational military deployment: the comparative 
experience of the Italian, British and Australian Armed Forces in East Timor.
 
Peragallo MS, Croft AM, Kitchener SJ.
 
Centro Studi e Ricerche di Sanita e Veterinaria dell Esercito, Via S. Stefano
Rotondo, 4, 00184 Rome, Italy. Email: [email protected]
 
Although their efficacy has been shown to be similar in south-east Asia,
doxycycline was less effective than mefloquine for malaria chemoprophylaxis in
East Timor. Lower adherence, higher incidence of adverse effects and reduced
bioavailability of doxycycline may have been possible causes. Mefloquine seems
therefore preferable in arduous and prolonged field conditions.
 
Trans R Soc Trop Med Hyg 2002 Sep-Oct;96(5):476-80 
 
Irrigated crop production is associated with less malaria than traditional
agricultural practices in Tanzania.
 
Ijumba JN, Shenton FC, Clarke SE, Mosha FW, Lindsay SW.
 
Tropical Pesticides Research Institute, P.O. Box 3024, Arusha, Tanzania.
Email: [email protected]
 
There is concern that crop irrigation that results in increased numbers of
vector mosquitoes will lead to a rise in malaria in local communities. We
evaluated the level of malaria experienced in 3 communities in northern Tanzania
with different agricultural practices: rice irrigation, sugar-cane irrigation
and traditional maize cultivation. Five cross-sectional surveys were used to
measure the prevalence of infection with falciparum malaria in 1-4 years old
children in each community over a period of 12 months. Active case detection was
also carried out to record clinical episodes of malaria during the study period.
Information on antimalarial measures was also recorded. Results from the
cross-sectional surveys showed that the overall prevalence of malaria parasites
was less near the rice irrigation (12.5%) and sugar-cane (16.9%) schemes than
the savannah village (29.4%). There were also significantly fewer clinical
episodes of malaria in the rice village (15 cases/1000 child-weeks at risk
[cwar]) than either the sugar-cane (36 cases/1000 cwar) or savannah (40
cases/1000 cwar) villages. Overall, rice irrigation was associated with less
malaria than alternative agricultural practices, despite the considerable
numbers of vectors produced in the paddies. This finding supports other studies
that indicate that irrigation in much of sub-Saharan Africa will not lead to
increased malaria. Nonetheless, African governments planning irrigation projects
need effective policies to encourage local communities to use personal
protection measures, such as insecticide-treated bednets, and to ensure that
these communities have access to effective antimalarial drugs and efficient
health services.
 
Parasitol Res 2002 Dec;89(1):26-33 
 
Parasite-specific immunoglobulin isotypes during lethal and non-lethal
murine malaria infections.
 
Smith EC, Taylor-Robinson AW.
 
School of Biology, University of Leeds, Clarendon Way, Leeds LS2 9JT, UK.
 
Production of parasite-specific antibodies is an important component of immunity
to blood stage malaria infection, as shown by several previous studies in rodent
models. However, no study has addressed the induction of humoral immunity by
different parasites in a genetically homogeneous host population. Here, levels
of parasite-specific immunoglobulin isotypes were measured during primary
infections of Plasmodium chabaudi and of Plasmodium yoelii in inbred NIH mice
inoculated with cloned lines of either avirulent or virulent erythrocytic
parasites. Non-lethal infections were characterized by early and late
significant upregulation of IgG2a and IgG1, respectively. In contrast, for
lethal infections, a slower, reduced IgG2a response correlated with a rapidly
fatal outcome prior to any significant synthesis of IgG1. It is proposed that
the sequential upregulated synthesis of parasite-specific IgG2a (cytophilic) and
IgG1 (non-cytophilic) is associated with protective immunity to blood stage
malaria infections in mice. This may provide an immunological framework for
examining humoral immunity to malaria in humans.
 
Sante 2002 May;12(3):331-335 
 
[Aetiologic factors and clinical features associated with thrombocytopenia
in Cameroonese adults: the importance of Plasmodium falciparum malaria]
 
[Article in French]
 
Mbanya D, Tapko JB, Azowe F, Kaptue L.
 
Departement d'hematologie, Faculte de medecine et des sciences biomedicales,
Universite de Yaounde I, BP 8046, Yaounde, Cameroun.
 
In order to determine the main aetiologies associated with thrombocytopenia in a
hospital setting of Cameroon, 180 adults with platelet counts <100x109/L were
examined and screened for a full blood count, thick and thin blood films, basic
coagulation tests (activated partial thromboplastine time, a one-stage Quick's
prothrombin time and a bleeding time), an HIV screening test as well as a bone
marrow aspirate using standard methods. Other tests were selectively done as
dictated by the suspected diagnosis. The major clinical findings among 180 cases
included fever >37.5 C (53.9%), splenomegaly (45.6%) and haemorrhage (30.6%).
The main laboratory findings were anaemia (defined as haemoglobin (Hb) <11g/dL)
in 80.6% of cases and a positive thick blood film (all confirmed to be P.
falciparum) in 30.6% of cases. Out of the 18 different aetiologies associated
with a low platelet count in the group studied, malaria appears as the unique
cause in 22.2% of cases. Petechial bleeding, bruising and epistaxis were the
major forms of bleeding involved (69.1%, 27.3%, and 23.6% respectively).
However, only 3 cases diagnosed with malaria showed any form of bleeding (mean
malaria parasite densities >15,000/muL of blood in each case). No other
haemostatic abnormalities were observed. It may be cost-effective for patients
with low platelet counts in malarial regions to be systematically screened for
malaria parasites.
 
Trends Parasitol 2002 Nov;18(11):510-4 
 
Reducing malaria by mosquito-proofing houses.
 
Lindsay SW, Emerson PM, Charlwood JD.
 
School of Biological and Biomedical Sciences, University of Durham, Science
Laboratories, South Road, DH1 3LE, Durham, UK
 
Sometimes, valuable lessons from history are forgotten, remain unknown, or
worse, are ignored. This article reminds us of the pioneering work of Angelo
Celli at the end of the 19th century, who demonstrated that people could be
protected from malaria by screening their homes against mosquitoes. Since then,
public health scientists have continued to show that simple changes in house
design have the potential for protecting people against this life-threatening
disease. Yet today, this type of intervention remains virtually ignored. The
literature reviewed here demonstrates the enormous potential of these methods to
reduce malaria, in the hope that it will stimulate scientific debate and further
research.
 
Trends Parasitol 2002 Nov;18(11):505-9 
 
Analysis of arthropod bloodmeals using molecular genetic markers.
 
Mukabana WR, Takken W, Knols BG.
 
Dept of Zoology, University of Nairobi, PO Box 30197, Nairobi, Kenya
 
Little is known about the transmission dynamics of human malaria and other
vector-borne diseases, partly because of the limited availability and
distribution of appropriate tools for quantifying human-mosquito contact rates.
Recent developments in molecular biology have allowed a significant increase in
the efficacy and reliability of bloodmeal identification, and DNA-based
molecular markers are now being harnessed for typing arthropod bloodmeals. The
extent to which these markers have been used for analysis of mosquito bloodmeals
and the potential they might have for the future is discussed, and the
contributions that the advent of PCR has made are examined here.
 
Trends Parasitol 2002 Nov;18(11):481 
 
Successful model vaccine against malaria.
 
Clark IA.
 
School of Biochemistry and Molecular Biology, Australian National University,
ACT 0200, Canberra, Australia
 
(No abstract available)
 
Malar J 2002 Nov 15;1(1):15 [epub ahead of print] 
 
Community cooperatives and insecticide-treated materials for malaria
control: a new experience in Latin America.
 
Kroeger A, Avinna A, Ordonnez-Gonzalez J, Escandon C.
 
Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK.
Email: [email protected]
 
BACKGROUND AND OBJECTIVES: Insecticide-treated materials (ITMs) are effective
 in substantially reducing the burden of malaria and other vector-borne diseases;
but how can high coverage rates of ITMs be achieved and maintained? In south
Mexico and on the Pacific and Atlantic coasts of Colombia 14 community-based
cooperatives offering three different kinds of ITM services (sale of
impregnation services; sale of impregnated nets; production of nets and sale of
impregnated nets) were formed and supervised by a national health service
(IMSS-SOLIDARIDAD, Mexico) and by an academic institution (the Colombian
Institute of Tropical Medicine) along with local district health services. The
objectives of this research were to analyse the processes and results of this
approach and to identify the favourable and limiting factors. METHODS: The
methods used for data collection and analysis were group discussions, individual
and semi-structured interviews with users and non-users of ITMs, individual
in-depth interviews with cooperative members and supervisors, checks of sales
book and observation of impregnation services. RESULTS: Coverage with
unimpregnated nets was above 50% in all study areas. The fastest increase of ITM
coverage was achieved through the exclusive sale of impregnation services.
Low-cost social marketing techniques were used to increase demand. The
large-scale production of nets in two cooperatives was only possible with the
aid of an international NGO which ordered impregnated bednets for their target
group. A number of favourable and limiting factors relating to the success of
ITM cooperatives were identified. Of particular importance for the more
successful Mexican cooperatives were: a) support by health services, b) smaller
size, c) lesser desire for quick returns and d) lower ITM unit costs.
CONCLUSIONS: ITM community cooperatives supported and supervised by the
health services have good potential in the Latin American context for achieving and
maintaining high impregnation rates.
 
Arch Inst Pasteur Madagascar 2001;67(1-2):27-30 
 
GIS and malaria in Madagascar [Article in French]
 
Rakotomanana F, Jeanne I, Duchemin JB, Pietra V, Raharimalala L, Tombo ML, Ariey
F.
 
Institut Pasteur de Madagascar, BP 1274, 101 Antananarivo, Madagascar.
 
Following the severe malaria outbreak in the central highlands in Madagascar in
1986, a vector control program by use DDT pm 75 house-spraying has been
implemented to operate in areas located at altitudes between 1000 and 1500 m.
Early treatment with chloroquine has also been incorporated in the control
program. To detect areas at particular high risk for malaria outbreak the
Geographic Information System (GIS) has been applied and tested. The study has
shown that the system can be used in malaria surveillance in order to identify
areas in which an intense distribution of Anopheles funestus can be anticipated
and, hence, targeted in spraying campaigns. The system may also be used to
monitor changes in anti-malarial drug resistance, in addition, to control of
other vector-born diseases.
 
Arch Inst Pasteur Madagascar 2001;67(1-2):21-6 
 
Malaria control in Madagascar [Article in French]
 
Sahondra Harisoa LJ, Pietra V, Tombo ML, Albonico M, Ranaivo LH, De Giorgi F,
Razanakolona J, D'Ancona FP, Sabatinelli G, Raveloson A, Modiano D,
Rakotondramarina D.
 
Ministere de la Sante, BP 460, 101 Antananarivo, Madagascar.
 
The central highlands in Madagascar are characterized by an unstable occurrence
of malaria with the risk of sporadic outbreaks. In major parts of the region DDT
indoor spraying campaigns have been carried out from 1993 to 1998. This strategy
was in 1999 replaced by another anti-vector intervention program targeting
residual foci as detected by a surveillance and early warning system. This
system is based on monitoring of presumptive malaria cases in the communities by
which the number of presumptive cases exceeded a defined warning threshold value
per month. The system was in the follow-up period shown to be very sensitive to
variation of the coverage of anti-vector interventions: the number of
presumptive cases decreased in the villages in which indoor spraying had been
carried out and a minor increase was observed in those villages, where indoor
spraying has been suspended. An increase of malaria cases was observed in 44
(20.8%) out of 212 study sites in the same period. The increase was in
particular predominant in areas at lower attitude at the outer zones of the
central highlands.
 
Clin Infect Dis 2002 Dec 15;35(12):1498-504 
 
Treatment of uncomplicated multidrug-resistant falciparum malaria with
artesunate-atovaquone-proguanil.
 
Van Vugt M, Leonardi E, Phaipun L, Slight T, Thway KL, McGready R, Brockman A,
Villegas L, Looareesuwan S, White NJ, Nosten F.
 
Shoklo Malaria Research Unit, Mae Sot, and Faculty of Tropical Medicine, Mahidol
University, Bangkok, Thailand; and Academic Medical Centre, Department of
Internal Medicine, Slotervaart Hospital, Amsterdam, The Netherlands.
 
In an open-label trial carried out on the northwest border of Thailand, 1596
patients with uncomplicated multidrug-resistant falciparum malaria were randomly
assigned to receive atovaquone-proguanil, atovaquone-proguanil-artesunate, or
artesunate-mefloquine and were followed up for 42 days. All 3 regimens were
highly effective and well tolerated. Fever duration and parasite clearance times
were significantly shorter among patients who received artesunate (P<.001).
Polymerase chain reaction genotyping confirmed that recrudescence occurred in 13
patients who received artesunate-mefloquine (2.4%), 5 who received
atovaquone-proguanil-artesunate (0.9%), and 15 who received atovaquone-proguanil
(2.8%). Adding artesunate to atovaquone-proguanil reduced the risk of failure
3-fold (95% confidence interval [CI], 1.1-8.2) and subsequent gametocyte
carriage 21-fold (95% CI, 14-30). Gastrointestinal complaints in the first 48 h
after initiation of treatment were more common among artesunate recipients, but
after day 2, dizziness, sleep disturbance, nausea, vomiting, and anorexia were
more common among mefloquine recipients (P</=.014).
Artesunate-atovaquone-proguanil is a highly effective and well-tolerated
treatment for multidrug-resistant falciparum malaria.
 
Clin Infect Dis 2002 Dec 15;35(12):1469-76 
 
Efficacy and safety of dihydroartemisinin-piperaquine (artekin) in 
Cambodian children and adults with uncomplicated falciparum malaria.
 
Denis MB, Davis TM, Hewitt S, Incardona S, Nimol K, Fandeur T, Poravuth Y, Lim
C, Socheat D.
 
European Commission, Cambodia Malaria Control Programme, and National Malaria
Centre, Phnom Penh, Cambodia.
 
The safety and efficacy of a novel combination of dihydroartemisinin (DHA) and
piperaquine, Artekin (Holleykin Pharmaceuticals), were assessed in 106 patients
(76 children and 30 adults) with uncomplicated falciparum malaria from 2 remote
areas in Cambodia. Age-based doses were given at 0, 8, 24, and 32 h. Mean total
DHA and piperaquine doses were 9.1 and 73.9 mg/kg, respectively, for children
and 6.6 and 52.9 mg/kg for adults. All patients became aparasitemic within 72 h.
Excluding the results for 1 child who died on day 4, there was a 96.9% 28-day
cure rate (98.6% in children and 92.3% in adults). Patients who had recrudescent
infection received low doses of Artekin. Side effects were reported by 22
patients (21%) but did not necessitate premature cessation of therapy. Although
Artekin is a promising and inexpensive option for antimalarial therapy, further
efficacy and pharmacokinetic studies are needed, especially for its use in
children.
 
Mem Inst Oswaldo Cruz 2002 Oct;97(7):1033-9 
 
In vitro chloroquine resistance modulation study on fresh isolates of 
Brazilian Plasmodium falciparum: intrinsic antimalarial activity of 
phenothiazine drugs.
 
Menezes CM, Kirchgatter K, Di Santi SM, Savalli C, Monteiro FG, Paula GA,
Ferreira EI.
 
Faculdade de Ciencias Farmaceuticas, Universidade de Sao Paulo, Sao Paulo, SP,
05508-900, Brasil.
 
Phenothiazine drugs - fluphenazine, chlorpromazine, methotrimeprazine and
trifluoperazine - were evaluated as modulating agents against Brazilian
chloroquine-resistant fresh isolates of Plasmodium falciparum. Aiming to
simulate therapeutic schedules, chloroquine was employed at the concentration
used for sensitive falciparum malaria treatment and anti-psychotic therapeutic
concentrations of the phenothiazine drugs were adopted in two-fold serial
dilutions. The in vitro microtechnique for drug susceptibility was employed.
Unlike earlier reported data, the phenothiazine modulating effect was not
observed. However, all the drugs demonstrated intrinsic antiplasmodial activity
in concentrations lower than those described in the literature. In addition,
IC50 estimates have been shown to be inferior to the usual anti-psychotic
therapeutic concentrations. Statistical analysis also suggested an increase in
the parasitaemia rate or, even, a predominant antiparasitic effect of
phenothiazine over chloroquine when used in combination.
 
Bull World Health Organ 2002;80(10):790-6 
 
Treatment uptake by individuals infected with Plasmodium falciparum in
rural Gambia, West Africa.
 
Von Seidlein L, Clarke S, Alexander N, Manneh F, Doherty T, Pinder M, Walraven
G, Greenwood B.
 
Medical Research Council Laboratories.
 
OBJECTIVE: To find out what proportion of Plasmodium falciparum infections are
treated in rural Gambia. METHODS: Subjects from four villages in the Gambia were
followed over nine months through visits to village health workers. Monthly
cross-sectional malaria surveys measured the prevalence of P. falciparum
infection. Linked databases were searched for treatment requests. Treated cases
were individuals with parasitaemia who requested treatment during narrow or
extended periods (14 or 28 days, respectively) before or after a positive blood
film was obtained. FINDINGS: Parasite prevalence peaked in November 1998, when
399/653 (61%) individuals had parasitaemia. Parasite prevalence was highest
throughout the study in children aged 5-10 years. Although access to treatment
was better than in most of sub-Saharan Africa, only 20% of infected individuals
sought medical treatment up to 14 days before or after a positive blood film.
Within two months of a positive blood film, 199/726 (27%) individuals with
parasitaemia requested treatment. Despite easy access to health care, less than
half (42%) of those with parasite densities consistent with malaria attacks
(5000/ l) requested treatment. High parasite density and infection during
October-November were associated with more frequent treatment requests.
Self-treatment was infrequent in study villages: in 3/120 (2.5%) households
antimalarial drugs had been used in the preceding malaria season. CONCLUSION:
Many P. falciparum infections may be untreated because of their subclinical
nature. Intermittent presumptive treatment may reduce morbidity and mortality.
It is likely that not all untreated infections were asymptomatic. Qualitative
research should explore barriers to treatment uptake, to allow educational
interventions to be planned.
 
Science 2002 Dec 6;298(5600):2002-6 
 
A role for the protease falcipain 1 in host cell invasion by the human malaria
parasite.
 
Greenbaum DC, Baruch A, Grainger M, Bozdech Z, Medzihradszky KF, Engel J, DeRisi
J, Holder AA, Bogyo M.
 
Department of Pharmaceutical Chemistry, Veterans Affairs Medical Center,
University of California, San Francisco, CA 94143, USA. 
Email: [email protected]
 
Cysteine proteases of Plasmodium falciparum are required for survival of the
malaria parasite, yet their specific cellular functions remain unclear. We used
a chemical proteomic screen with a small-molecule probe to characterize the
predominant cysteine proteases throughout the parasite life cycle. Only one
protease, falcipain 1, was active during the invasive merozoite stage. Falcipain
1-specific inhibitors, identified by screening of chemical libraries, blocked
parasite invasion of host erythrocytes, yet had no effect on normal parasite
processes such as hemoglobin degradation. These results demonstrate a specific
role for falcipain 1 in host cell invasion and establish a potential new target
for antimalarial therapeutics.
 

J Immunol 2002 Dec 15;169(12):6681-5 
 
Cutting Edge: A New Tool to Evaluate Human Pre-Erythrocytic Malaria 
Vaccines: Rodent Parasites Bearing a Hybrid Plasmodium falciparum
Circumsporozoite Protein.
 
Persson C, Oliveira GA, Sultan AA, Bhanot P, Nussenzweig V, Nardin E.
 
Michael Heidelberger Division of Immunology, Department of Pathology, and
Department of Medical and Molecular Parasitology, New York University School of
Medicine, New York, NY 10016.
 
Malaria vaccines containing the Plasmodium falciparum Circumsporozoite protein
repeat domain are undergoing human trials. There is no simple method to evaluate
the effect of vaccine-induced responses on P. falciparum sporozoite infectivity.
Unlike the rodent malaria Plasmodium berghei, P. falciparum sporozoites do not
infect common laboratory animals and only develop in vitro in human hepatocyte
cultures. We generated a recombinant P. berghei parasite bearing P. falciparum
Circumsporozoite protein repeats. These hybrid sporozoites are fully infective
in vivo and in vitro. Monoclonal and polyclonal Abs to P. falciparum repeats
neutralize hybrid parasite infectivity, and mice immunized with a P. falciparum
vaccine are protected against challenge with hybrid sporozoites.
 
Nat Med 2002 Dec 9; [epub ahead of print] 
 
Plasmodium falciparum erythrocyte invasion through glycophorin C and
selection for Gerbich negativity in human populations.
 
Maier AG, Duraisingh MT, Reeder JC, Patel SS, Kazura JW, Zimmerman PA, Cowman
AF.
 
The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia.
 
Geographic overlap between malaria and the occurrence of mutant hemoglobin and
erythrocyte surface proteins has indicated that polymorphisms in human genes
have been selected by severe malaria. Deletion of exon 3 in the glycophorin C
gene (called GYPCDeltaex3 here) has been found in Melanesians; this alteration
changes the serologic phenotype of the Gerbich (Ge) blood group system,
resulting in Ge negativity. The GYPCDeltaex3 allele reaches a high frequency
(46.5%) in coastal areas of Papua New Guinea where malaria is hyperendemic. The
Plasmodium falciparum erythrocyte-binding antigen 140 (EBA140, also known as
BAEBL) binds with high affinity to the surface of human erythrocytes. Here we
show that the receptor for EBA140 is glycophorin C (GYPC) and that this
interaction mediates a principal P. falciparum invasion pathway into human
erythrocytes. EBA140 does not bind to GYPC in Ge-negative erythrocytes, nor can
P. falciparum invade such cells using this invasion pathway. This provides
compelling evidence that Ge negativity has arisen in Melanesian populations
through natural selection by severe malaria.
 

Proc Natl Acad Sci U S A 2002 Dec 10;99(25):16348-16353 
 
Mosaic organization and heterogeneity in frequency of allelic recombination
of the Plasmodium vivax merozoite surface protein-1 locus.
 
Putaporntip C, Jongwutiwes S, Sakihama N, Ferreira MU, Kho WG, Kaneko A, 
Kanbara H, Hattori T, Tanabe K.
 
Laboratory of Biology and Department of Mathematics, Osaka Institute of
Technology, Osaka 535-8585, Japan; Department of Protozoology, Institute of
Tropical Medicine, Nagasaki University, Nagasaki 852-8523, Japan; Department of
Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330,
Thailand Asia; Department of Parasitology, Institute of Biomedical Sciences,
University of Sao Paulo, 05508-900, Sao Paulo (SP), Brazil South America;
Department of Parasitology and Institute of Malariology, Inje University College
of Medicine, Pusan 614-735, South Korea Asia; and Department of International
Affairs and Tropical Medicine, Tokyo Women's Medical University School of
Medicine, Tokyo 162-866, Japan.
 
The organization and allelic recombination of the merozoite surface protein-1
gene of Plasmodium vivax (PvMsp-1), the most widely prevalent human malaria
parasite, were evaluated in complete nucleotide sequences of 40 isolates from
various geographic areas. Alignment of 31 distinct alleles revealed the mosaic
organization of PvMsp-1, consisting of seven interallele conserved blocks
flanked by six variable blocks. The variable blocks showed extensive variation
in repeats and nonrepeat unique sequences. Numerous recombination sites were
distributed throughout PvMsp-1, in both conserved blocks and variable block
unique sequences, and the distribution was not uniform. Heterozygosity of
PvMsp-1 alleles was higher in Asia (0.953 +/- 0.009) than in Brazil (0.813 +/-
0.047). No identical alleles were shared between Asia and Brazil, whereas all
but one variable block nonrepeat sequence found in Brazil occurred in Asia.
These observations suggest that P. vivax populations in Asia are ancestral to
Brazilian populations, and that PvMsp-1 has heterogeneity in frequency of
allelic recombination events. Recurrent origins of new PvMsp-1 alleles by
repeated recombination events were supported by a rapid decline in linkage
disequilibrium between pairs of synonymous sites with increasing nucleotide
distance, with little linkage disequilibrium at a distance of over 3 kb in a P.
vivax population from Thailand, evidence for an effectively high recombination
rate of the parasite. Meanwhile, highly reduced nucleotide diversity was noted
in a region encoding the 19-kDa C-terminal epidermal growth factor-like domain
of merozoite surface protein-1, a vaccine candidate.
 
Arch Inst Pasteur Madagascar 2000;66(1-2):32-5 
 
Anopheles gambiae and Anopheles funestus in Madagascar [Article in French]
 
Rakotondraibe ME, Le Goff G, Rajaonarivelo E, Romi R, Raharimanga R,
Rajaonarivelo V, Rabarison P.
 
Service de Lutte contre le Paludisme, Ministere de la Sante de Madagascar, BP
460-101 Antananarivo-Madagascar.
 
In 1991, Anopheles gambiae and Anopheles funestus, the main malaria vectors in
the Highlands of Madagascar, were reported to be fully susceptible to DDT;
nevertheless a slight decrease in the susceptibility levels was recorded when
compared with previous assays carried out in 1962. From 1993 to 1997, five
cycles of indoor residual spraying have been carried out in the Highlands: a
total of 1,482,000 kg of 70% wp DDT have been used for the treatment of houses
and animal shelters. From 1996 to 1999, adult mosquito susceptibility tests to
DDT and to some pyrethroids (lambdacyalothrine, deltamethrine, permethrine and
cyfluthrine) have been carried out on samples collected in 20 areas of the
Highlands. Bioassays were carried out following the WHO standard method. All
tested populations of An. funestus showed a full susceptibility to DDT. An.
gambiae showed a widespread decrease in the susceptibility to DDT, particularly
marked in the region of the capital city Antananarivo. Both species were
susceptible to pyrethroids.
 
Arch Inst Pasteur Madagascar 2000;66(1-2):26-31 
 
Evolution of the chemoresistance of Plasmodium falciparum to chloroquine
in Madagascar [Article in French]
 
Raharimalala AL, Randrianarivelojosia M, Randriamanantena A, Ranarivelo LA,
Jaureguiberry S, Rason MA, Rakotomalala E, Ariey F.
 
Institut Pasteur de Madagascar, BP 1274, 101 Antananarivo-Madagascar.
 
In order to document the evolution of the chemoresistance of Plasmodium
falciparum to chloroquine in Madagascar, a study was carried out in Sainte-Marie
island located at 6 km on the eastern border of the country. Symptomatic malaria
patients who satisfied criteria for resistance testing, were recruited by a
process of passive case detection at two clinics. These patients were enrolled
in a sensitivity 14-day in vivo test for uncomplicated P. falciparum malaria
attacks. All subjects received a supervised therapeutic regimen of chloroquine
(25 mg base/kg over 3 days). Parasitemia and symptoms were monitored for 14
days. 62 (93.9%) out of the 66 enrolled patients completed the 14-day follow-up.
A total of 50 of 62 patients (80.6%) presented an adequate clinical response.
Early and late treatment failures were observed in 3 (4.8%) and 9 (14.5%)
patients respectively. Failure therapeutic treatments treated with
sulfadoxine-pyrimethamine were successful. Chloroquine remains effective in the
treatment of malaria due to P. falciparum and therefore its choice as a first
line drug remains justified. Likewise, guidelines for the use of
sulfadoxine-pyrimethamine as second line drug are adequate. In vitro, 4
resistances out of 27 successful tests to chloroquine (14.8%) and 1 resistance
out of 25 successful tests to mefloquine (4%) were recorded. No resistance to
quinine nor to amodiaquine were noticed. Alternative antimalarial drugs such as
quinine, amodiaquine or mefloquine can be used in patients for whom the
treatment with chloroquine is not possible. Nevertheless, the level of
therapeutic failures to chloroquine detected in this study highlights the need
and importance of drug sensitivity test for the development of a rational
national antimalarial drug policy.
 

Arch Inst Pasteur Madagascar 2000;66(1-2):23-5 
 
Epidemiological and clinical survey and evaluative aspects of severe 
malaria in Antananarivo [Article in French]
 
Raobijaona H, Randrianotahina CH, Razanamparany M.
 
Hopital general de Befelatanana, Centre Hospitalier Universitaire
d'Antananarivo, BP 8394-101 Antananarivo-Madagascar.
 
The definition of severe malaria is no longer limited to cerebral malaria, but
it is as well extended to other clinical forms of the disease. The authors
reported the epidemiological and clinical survey and evaluative aspects of
severe malaria in Antananarivo. This retrospective study included 48 children
less than 15 years old, hospitalized at the paediatric unit Debre of the Centre
Hospitalier Universitaire de Befelatanana (Antananarivo) for severe malaria as
defined by world Health Organization (WHO) criteria. The hospitalization
frequency was 0.87%. Higher frequency was noticed for the children less than 5
years old, the sex-ratio was 1.4/1. The cerebral complications as seen in many
African countries were the most frequent clinical form. The death rate was
14.58% and the proportional mortality was 1.07%, 2.1% of the patients had
sequel. The improvement of severe malaria prognosis was not only on better
equipment in intensive care wards, but also on improved and early diagnosis and
management.
 
Arch Inst Pasteur Madagascar 1996;63(1-2):12-5 
 
Results of paludometric and entomological studies carried-out for two 
years: Ampanihy and Ankilimivory located in the South of Madagascar
[Article in French]
 
Champetier de Ribes G, Rakotoson JD, Ranaivoson G, Rabeson D.
 
Service de Surveillance Epidemiologique, Ministere de la Sante, Direction de la
Lutte contreles Maladies Transmissibles (DLMT), BP 460, 101 Antananarivo,
Madagascar.
 
The authors reported the results of paludometric and entomological studies
carried-out for two years: 1995-1996 in two localities: Ampanihy and
Ankilimivory located in the South of Madagascar. These studies followed a
suspect malaria epidemic in Ankilimivory in June and July 1994; the population
plasmodic index was of 45%. In April 1995, this data was of 35% in Ampanihy and
of 15% in Ankilimivory. Entomological studies carried out in April 1996 allowed
to find Anopheles funestus in Ankilimivory and Anopheles gambiae l. s. in the
two localities. Both the endemicity of malaria and the role of A. funestus had
to be taken into account in the southern part of Madagascar. Until now, rare
epidemics in this area were thought to occur only when climatic conditions were
favorable, mainly during the rainy season. However, other factors, linked with
the development could also facilitate the upset of epidemics, e.g.: irrigation
programmes.
 

Trop Med Int Health 2002 Dec;7(12):1042-6 
 
Malaria control: constraints and opportunities.
 
Kager PA.
 
Department of Infectious Diseases, Tropical Medicine and AIDS, Academic Medical
Center, University of Amsterdam, Amsterdam, The Netherlands.
 
The malaria eradication campaign of the 1950s and 1960s achieved elimination of
malaria from the industrialized world and drastic reduction of malaria
elsewhere, especially Asia. In Africa, eradication was hardly attempted. For
various reasons, results could not be maintained. Eradication had to be given
up, control became the policy. Since 1992 malaria control is based on four
principles: early diagnosis and treatment; selective and sustainable preventive
measures, including vector control; detection, containment and prevention of
epidemics, and building up of local capacity. Several constraints with the
presently available tools are discussed. Major problems are drug resistance and
poor performance of the health sector. International awareness of the problem
and international co-operation, the financial resources now available and
scientific advances offer opportunities for a concerted effort to reduce the
burden of malaria. Operational research, field research and implementation and
improvement of the peripheral health service will be of paramount importance.
 
Trop Med Int Health 2002 Dec;7(12):1031-41 
 
Increasing antimalarial drug resistance in Uganda and revision of the 
national drug policy.
 
Kamya MR, Bakyaita NN, Talisuna AO, Were WM, Staedke SG.
 
Makerere University Medical School, Kampala, Uganda Ministry of Health, Kampala,
Uganda Rubaga Hospital, Kampala, Uganda Department of Medicine, San Francisco
General Hospital, University of California, San Francisco, CA, USA.
 
Chloroquine (CQ) resistance was first documented in Uganda in 1988. Subsequent
surveillance of antimalarial drug resistance, conducted by the Ugandan Ministry
of Health and several research organizations, suggests that resistance to CQ is
now widespread, reaching critical levels in many areas of the country. In June
2000, the Ministry of Health held a National Consensus Meeting to evaluate the
available drug efficacy data and review the national antimalarial drug policy.
After extensive debate, the combination of CQ + sulfadoxine-pyrimethamine (SP)
was chosen to replace CQ as the first-line treatment of uncomplicated malaria as
an interim policy. This review evaluates the in vivo drug efficacy studies
conducted in Uganda since 1988 and issues confronted in revision of the drug
policy. The Ugandan experience illustrates the challenges faced by sub-Saharan
African countries confronted with rising CQ resistance but limited data on
potential alternative options. The choice of CQ + SP as a provisional policy in
the absence of prerequisite efficacy, safety and cost-effectiveness data
reflects the urgency of the malaria treatment problem, and growing pressure to
adopt combination therapies. Surveillance of CQ + SP treatment efficacy,
collection of additional data on alternative regimens and active consensus
building among key partners in the malaria community will be necessary to
develop a rational long-term antimalarial treatment policy in Uganda.
 
Trop Med Int Health 2002 Dec;7(12):1022-30 
 
Do insecticide-treated bednets have an effect on malaria vectors?
 
Takken W.
 
Laboratory of Entomology, Wageningen University, Wageningen, The Netherlands.
 
The use of insecticide-treated bednets (ITNs) has been widely adopted as an
important method for malaria control. Few data exist on effects of ITNs on
mosquito biology and ecology, other than the development of insecticide
resistance against the insecticides used. There is no hard evidence that the
insecticide resistance recorded is the result of insecticidal use on bednets or
from agricultural use. Resistance against pyrethroids, the preferred class of
insecticides for ITN use, has been recorded from countries in Asia, Africa and
South America. Resistance is expressed as reduced excito-repellency and
mortality of mosquitoes exposed to insecticide-treated materials. In the absence
of resistance, however, most studies on ITN effects report a reduced survival of
adult mosquitoes as well as mass killing. Other effects are highly variable, and
shifts in time of biting, feeding site and blood hosts have occasionally been
reported, but not in proportion to the scale of ITN use. In general, a reduced
sporozoite rate is recorded in ITN programmes. Because many of the anticipated
behavioural effects caused by insecticidal use will be avoided by the use of
untreated nets, studies on the efficacy of untreated nets are required. Examples
are presented in which untreated nets provided a reasonable degree of protection
against malaria.
 
Trop Med Int Health 2002 Dec;7(12):1012-21 
 
The molecular epidemiology of malaria.
 
Greenwood B.
 
Department of Infectious and Tropical Diseases, London School of Hygiene and
Tropical Medicine, London, UK.
 
This review discusses how the use of molecular genetic techniques such as the
polymerase chain reaction are helping in the management and prevention of
malaria.
 
infection in owl and squirrel monkeys, whose parasitemia increased by. 22,000
parasites/uL daily during a 14-day interval. After malaria challenge,
unprotected animals had significant changes in hematologic values. These changes
could not be completely attributed to the increase in the parasite counts.
 
Am J Trop Med Hyg 2002 Oct;67(4):392-5 
 
Molecular epidemiology of malaria in Cameroon. XIV. Plasmodium 
falciparum chloroquine resistance transporter (PFCRT) gene sequences 
of isolates before and after chloroquine treatment.
 
Basco LK, Ndounga M, Ngane VF, Soula G.
 
Institut de Recherche pour le Developpement (IRD)-Laboratoire de Recherche sur
le Paludisme, Organisation de Coordination pour la lutte contre les Endemies en
Afrique Centrale (OCEAC), B. P. 288, Yaounde, Cameroon.
 
Laboratory studies have strongly suggested that the gene coding for Plasmodium
falciparum chloroquine resistance transporter (PFCRT) may play a determinant
role in chloroquine resistance. A clinical study in Mali also found evidence for
selection of the key PFCRT amino acid substitution, Lys76Thr, in patients who
fail to respond to chloroquine treatment. To test the hypothesis that in vivo
selection of mutant PFCRT alleles occurs after chloroquine treatment, PFCRT and
merozoite surface antigen 2 (msa-2) polymorphisms were compared between 61
pretreatment and posttreatment paired samples from children with either clinical
or parasitologic failure. There were six wild-type PFCRT alleles, 44 mutant
alleles, and 11 mixed alleles among pretreatment isolates. All posttreatment
parasites had mutant PFCRT alleles. Recrudescence accounted for 42 of 61
posttreatment infections, while 19 posttreatment infections were due to new
infection (including all isolates with Lys-76 before treatment and Thr-76 after
treatment). Seven pretreatment isolates with mixed PFCRT alleles had only Thr-76
on recrudescence, providing a direct evidence for in vivo selection for mutant
PFCRT. Although the presence of mutant PFCRT alleles in pretreatment isolates is
not predictive of chloroquine treatment failure, our data support the hypothesis
that in vivo selection for recrudescent parasites carrying mutant PFCRT alleles
occurs. These results may have important implications for the future
surveillance of chloroquine resistance by the use of molecular markers.
 
Am J Trop Med Hyg 2002 Oct;67(4):388-91 
 
Molecular epidemiology of malaria in Cameroon. XIII. Analysis of pfcrt
mutations and in vitro chloroquine resistance.
 
Basco LK.
 
Institut de Recherche pour le Developpement (IRD) and Laboratoire de Recherche
sur le Paludisme, Organisation de Coordination pour la lutte contre les Endemies
en Afrique Centrale (OCEAC), B. P. 288, Yaounde, Cameroon.
 
The key Lys76Thr amino-acid substitution in Plasmodium falciparum
chloroquine-resistance transporter (PfCRT) has been shown to be a reliable
marker associated with chloroquine-resistant phenotype in reference clones, but
few discordant results have been observed in field isolates. To further examine
the relationship between in vitro chloroquine response and pfcrt alleles, the
entire exon 2 of the pfcrt gene of 157 Cameroonian isolates was sequenced. All
isolates were characterized as having either Cys-72, Met-74, Asn-75, and Lys-76
(wild-type alleles), Cys-72, Ile-74, Glu-75, and Thr-76 (mutant alleles), or
mixed alleles. The hypothetical threshold 50% inhibitory concentration (IC50)
set at 100 nM distinguished between isolates carrying the wild-type alleles and
those with mutant alleles in a large majority of cases (135 of 139 isolates with
unmixed pfcrt alleles). Isolates presenting discordant results generally had
IC50s within an intermediate range. In vitro chloroquine response of isolates
with mixed pfcrt alleles was highly variable. Although discordant results
between chloroquine-resistant phenotype and pfcrt alleles were not explained by
the immediate adjacent codons, the key Lys76Thr codon may prove to be a highly
reliable genetic marker for the epidemiologic monitoring of chloroquine
resistance by means of molecular techniques.
 
Am J Trop Med Hyg 2002 Oct;67(4):383-7 
 
Molecular epidemiology of malaria in Cameroon. XII. In vitro drug 
assays and molecular surveillance of chloroquine and proguanil resistance.
 
Basco LK.
 
Institut de Recherche pour le Developpement (IRD) and Laboratoire de Recherche
sur le Paludisme, Organisation de Coordination pour la lutte contre les Endemies
en Afrique Centrale (OCEAC), B. P. 288, Yaounde, Cameroon. 
Email: [email protected]
 
Chloroquine-proguanil combination is one of the options for chemoprophylaxis.
The rapid evolution of drug resistance status requires a constant upgrade of
epidemiologic data. Due to various difficulties in conducting prospective
clinical studies on the prophylactic efficacy of the drug combination,
especially in highly chloroquine-resistant zones, in vitro drug sensitivity
assays and specific molecular markers for chloroquine (Plasmodium falciparum
chloroquine-resistance transporter, pfcrt) and cycloguanil (a biologically
active metabolite of proguanil; dihydrofolate reductase, dhfr) resistance were
evaluated as an alternative approach in this study. Of 116 isolates, 62 (53.4%)
were doubly resistant in vitro to chloroquine (IC50 > or = 100 nM) and
cycloguanil (IC50 > or = 15 nM). Likewise, 62 of 118 isolates (52.5%) carried
both the mutant Thr-76 pfcrt allele and at least one dhfr mutant allele (1 with
a single Asn-108 allele, 8 with double Arg-59 and Asn-108 mutations, and 53 with
triple Ile-51, Arg-59, and Asn-108 mutations). The in vitro drug response
corresponded with the presence or absence of key mutation(s) in the pfcrt and
dhfr genes. These results suggest the high proportion of P. falciparum isolates
in southern Cameroon that may not respond to chloroquine-proguanil combination.
 
Am J Trop Med Hyg 2002 Oct;67(4):411-4 
 
Plasmodium malariae infection boosts Plasmodium falciparum gametocyte
production.
 
McKenzie FE, Jeffery GM, Collins WE.
 
Fogarty International Center, National Institutes of Health, Bethesda, Maryland
20892, USA. Email: [email protected]
 
We analyzed records of malaria therapy patients sequentially or simultaneously
inoculated with Plasmodium falciparum and Plasmodium malariae. Gametocyte
production was enhanced in P. falciparum by prior or concurrent P. malariae
infection but diminished or unaffected in P. malariae by P. falciparum.
Conversely, asexual-form production was diminished in P. malariae but unaffected
in P. falciparum.
 

Am J Trop Med Hyg 2002 Oct;67(4):400-5 
 
Genetics of drug-resistant Plasmodium falciparum malaria in the 
Venezuelan state of Bolivar.
 
Contreras CE, Cortese JF, Caraballo A, Plowe CV.
 
Immunology Institute, School of Medicine, Central University, Caracas,
Venezuela. Email: [email protected]
 
The state of Bolivar in Venezuela experiences episodic outbreaks of
multidrug-resistant Plasmodium falciparum malaria. We obtained P.
falciparum-infected blood samples in Bolivar in 1998-2000, and performed
molecular assays for mutations conferring resistance to the antifolate
combination of sulfadoxine-pyrimethamine (SP) and to chloroquine. All infections
carried the dihydrofolate reductase (dhfr) S108A and N51I mutations, and 45% of
the infections had the dhfr C50R mutation, which has been implicated in
mid-level resistance to SP. Two dihydropteroate synthase (dhps) mutations also
involved in SP resistance, A581G and K540E, were detected in 90% and 67% of the
samples, respectively. The dhfr 1164L mutation, which confers high-level
resistance, was not identified. The P. falciparum chloroquine resistance
transporter (pfcrt) K76T mutation, which is critical for chloroquine resistance,
was found in 167 of 168 infections. Six dhfr/dhps allelotypes and four
pfcrt-resistant alleles were observed. Their interrelationships suggest a
semi-clonal propagation of P. falciparum malaria in Bolivar, and an invasion of
multi-resistant pathogens from Brazil. Despite national restrictions on the use
of SP and chloroquine, genotypic resistance to these therapies remains
widespread in Bolivar.
 
Am J Trop Med Hyg 2002 Oct;67(4):396-9 
 
Failure of national guidelines to diagnose uncomplicated malaria in 
Bangladesh.
 
Faiz MA, Yunus EB, Rahman MR, Hossain MA, Pang LW, Rahman ME, Bhuiyan SN.
 
Malaria Research Group, Chittagong Medical College, Chittagong, 4000,
Bangladesh.
 
During the mid 1990s, national guidelines were established in accordance with
World Health Organization recommendations for the diagnosis of uncomplicated
malaria in Bangladesh. Based on simple clinical and epidemiologic criteria these
guidelines were designed to be applied outside of tertiary care centers where
microscopy was not feasible. We evaluated the positive predictive value (PPV) of
these criteria using microscopic slide examinations as the gold standard in 684
subjects diagnosed and treated for malaria, sampling from eight subdistrict
centers. The PPV for malaria was 32% with 19% for falciparum and 14% for
Plasmodium vivax. Medical officers assigned to the study also gave their own
clinical impression of whether cases could have been malaria. With the
additional criteria of a medical officers' diagnosis, the PPV increased
negligibly to 37% with 23% and 14% for falciparum and vivax, respectively. Since
the PPV of diagnosis is low and cannot be improved on clinical grounds alone, we
recommend the incorporation of laboratory diagnosis. This is especially
important as we detect resistance to the first-line therapy chloroquine and
require more expensive, potentially more toxic, regimens.
 
Am J Trop Med Hyg 2002 Oct;67(4):378-82 
 
Molecular epidemiology of malaria in Cameroon. XI. Geographic 
distribution of Plasmodium falciparum isolates with dihydrofolate 
reductase gene mutations in southern and central Cameroon.
 
Basco LK, Ndounga M, Tejiokem M, Ngane VF, Youmba JC, Ringwald P, Soula G.
 
Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la
lutte contre les Endemies en Afrique Centrale (OCEAC) and Unite de Recherche
Paludologie Afro-tropicale, Institut de Recherche pour le Developpement (IRD),
Yaounde, Cameroon.
 
The DNA sequence of the dihydrofolate reductase (dhfr) gene, a molecular marker
for pyrimethamine resistance, was determined for 178 field isolates of
Plasmodium falciparum collected along the east-west axis in southern Cameroon.
The proportion of isolates having the wild-type dhfr allele varied from 48.1% in
the east (city of Bertoua) to 11.3-15.7% in central provinces (Yaounde and
Eseka) and 0% in the littoral region (port city of Douala). Isolates with a
single Asn-108 mutation or double mutations (Ile-51 or Arg-59 and Asn-108)
constituted approximately 10% of the samples. Isolates with triple mutations
(Ile-51, Arg-59, and Asn-108) were present in an equal proportion (48.1%) as the
wild-type isolates in the east (Bertoua), while triple mutations predominated in
Yaounde (62.3%), Eseka (62.7%), and Douala (78.9%). The distribution of triple
dhfr mutations along the east-west axis in southern Cameroon suggests the
presence of a decreasing gradient from the west coastal region to the central
region and then to the east towards the interior of the country.
 
Am J Trop Med Hyg 2002 Oct;67(4):371-7 
 
Characteristics of severe anemia and its association with malaria in young
children of the Kassena-Nankana District of northern Ghana.
 
Owusu-Agyei S, Fryauff DJ, Chandramohan D, Koram KA, Binka FN, Nkrumah FK, Utz
GC, Hoffman SL.
 
Navrongo Health Research Center, Ministry of Health, Navrongo, Upper East
Region, Ghana.
 
Severe anemia is thought to be the principal underlying cause of malaria death
in areas of intense seasonal malaria transmission such as the Kassena-Nankana
District of northern Ghana. Factors associated with severe anemia in young
children, 6-24 months old, were elucidated by analyzing results of 2
malaria-associated anemia surveys (1996, 2000), separated by 4 years, but
conducted in the same community and at the same seasonal time point.
Age-adjusted comparison confirmed that the proportion of severely anemic
children and overall mean hemoglobin (Hb) levels in the November 2000 sample
were significantly improved over those of the 1996 sample (17.5 versus 26.4%, P
= 0.03; Hb 7.5 versus 6.9 g/dL, P = 0.002). Weight-for-age Z-scores also
indicated a significant improvement in the 2000 sample (-1.93 versus -2.20, P <
0.05). Independently, each survey identified statistically significant
associations between severe anemia and age, parasite rate, fever, and sex.
Relative to children with Hb > or = 6.0 g/dL, those with severe anemia (Hb < 6.0
g/dL) were older, more frequently parasitemic (odds ratio [OR], 1.60; 95%
confidence interval [CI], 1.08-2.35), more often febrile (OR, 2.44; 95% CI,
1.71-3.48), and predominantly male (OR, 1.50; 95% CI, 1.05-2.13). An association
was identified in both surveys between severe anemia and residence in the
northern part of the district, but no clear link was observed in relation to
irrigation. Blood transfusions, a likely surrogate index of severe anemia in
young children, followed a distinct seasonal pattern. Evidence suggests that
dramatic peaks and troughs of severe anemia are regular and possibly predictable
events that may be used to gauge the health and survival of young children in
this area.
 
Vaccine 2002 Dec 13;21(3-4):269-80 
 
Immediate-type hypersensitivity and other clinical reactions in volunteers
immunized with a synthetic multi-antigen peptide vaccine (PfCS-MAP1NYU)
against Plasmodium falciparum sporozoites.
 
Edelman R, Wasserman SS, Kublin JG, Bodison SA, Nardin EH, Oliveira GA, Ansari
S, Diggs CL, Kashala OL, Schmeckpeper BJ, Hamilton RG.
 
Department of Medicine, Center for Vaccine Development, University of Maryland
School of Medicine, Room 480, 685 West Baltimore Street, 21201, Baltimore, MD,
USA
 
We tested the clinical reactions to a synthetic, Plasmodium falciparum,
circumsporozoite multiple antigen peptide (MAP) vaccine in 39 volunteers
immunized two to three times over 2-8 months using a dose escalation design.
Immediate pain at the injection site was associated with the adjuvant QS-21
(P<0.001), and delayed local inflammatory reactions were associated with
high-titered circulating IgG anti-MAP antibody (P=0.03). Because two volunteers
developed acute, systemic urticaria after the third immunization associated with
development of serum IgE MAP antibody, we employed immediate-type
hypersensitivity skin tests (ITH-STs) using intradermal injections of diluted
MAP vaccine to identify persons sensitized to the vaccine. ITH-STs were negative
in seven volunteers tested 27 days after the first vaccination, but six of these
individuals developed positive wheal and flare reactions when tested 14 or 83
days after the second vaccination; IgE MAP antibody was detected in only one of
them. Another cohort of 16 volunteers, including the 2 allergic individuals,
were ITH-ST negative when first tested late after their second or third
vaccination at 6-7 months. Five of five non-immunized persons were also ITH-ST
negative. ITH-STs may help identify individuals sensitized to malaria peptides
and at potential risk of developing systemic allergic reactions after
re-vaccination.
 

Ceylon Med J 2002 Sep;47(3):83-5 
 
A safety and efficacy trial of artesunate, sulphadoxine-pyrimethamine and
primaquine in P falciparum malaria.
 
Weerasinghe KL, Galappaththy G, Fernando WP, Wickremasinghe DR, Faizal HM,
Wickremasinghe AR.
 
Base Hospital, Moneragala.
 
OBJECTIVE: To determine effectiveness and safety of the combination of
artesunate, sulphadoxine + pyrimethamine and primaquine in the treatment of P
falciparum malaria. DESIGN: A hospital based prospective study. SETTING: Base
Hospital, Moneragala. METHODS: In 30 P falciparum infected patients admitted to
the hospital, blood was taken for estimation of haemoglobin, white cell counts,
and serum levels of aspartate aminotransferase, alanine aminotransferase,
bilirubin and creatinine. They were administered artesunate, sulphadoxine +
pyrimethamine (S + P) and primaquine on day 0 (artesunate 4 mg/kg, sulphadoxine
25 mg/kg, pyrimethamine 1.25 mg/kg and primaquine 0.75 mg/kg), and only
artesunate on days 1 and 2 (artesunate 4 mg/kg each day). Blood was examined for
malarial parasites, and patients were assessed on days 1, 2, 7, 14, 21 and 28.
Patients assessed the severity of selected symptoms. Biochemical analyses were
done on day 0 and repeated on days 7 and 28. RESULTS: Eight patients presented
with fever which resolved in 7 patients in 48 hours. Asexual parasites were
cleared in 80% of the 30 patients within 24 hours of treatment and in all 30 by
day 7. Gametocytaemia cleared in all patients by day 14. There were no adverse
effects experienced by the patients. The white cell and differential counts,
liver enzymes and creatinine levels were within normal limits on all follow up
days. CONCLUSIONS: The combination of artesunate, S + P and primaquine was
found to be effective and safe in the treatment of uncomplicated P falciparum malaria.