Social Sciences and
Effect of large-scale
social marketing of insecticide-treated nets on child survival in rural
Tanzania - Lancet 357(9264) April 21, 2001
(Full-text available via the
Lancet web site at http://www.thelancet.com
or send an email to [email protected]
to request an electronic copy)
Joanna R M Armstrong Schellenberg, Salim Abdulla, Rose
Nathan, Oscar Mukasa, Tanya J Marchant, Nassor Kikumbih, Adiel K Mushi,
Haji Mponda, Happiness Minja, Hassan Mshinda, Marcel Tanner, Christian
Correspondence to: Joanna R M Armstrong
Schellenberg, Orchard Ground Cottage, Cublington, Bedfordshire LU7 OLJ, UK
Insecticide-treated nets have proven efficacy as a
malaria-control tool in Africa. However, the transition from efficacy to
effectiveness cannot be taken for granted. We assessed coverage and the
effect on child survival of a large-scale social marketing programme for
insecticide-treated nets in two rural districts of southern Tanzania with
high perennial malaria transmission.
Socially marketed insecticide-treated nets were introduced
step-wise over a 2-year period from May, 1997, in a population of 480 000
people. Cross-sectional coverage surveys were done at baseline and after
1, 2, and 3 years. A demographic surveillance system (DSS) was set up in
an area of 60 000 people to record population, births, and deaths. Within
the DSS area, the effect of insecticide-treated nets on child survival was
assessed by a case-control approach. Cases were deaths in children aged
between 1 month and 4 years. Four controls for each case were chosen from
the DSS database. Use of insecticide-treated nets and potential
confounding factors were assessed by questionnaire. Individual
effectiveness estimates from the case-control study were combined with
coverage to estimate community effectiveness.
Insecticide-treated net coverage of infants in the DSS
area rose from less than 10% at baseline to more than 50% 3 years later.
Insecticide-treated nets were associated with a 27% increase in survival
in children aged 1 month to 4 years (95% CI 3-45). Coverage in such
children was higher in areas with longer access to the programme. The
modest average coverage achieved by 1999 in the two districts (18% in
children younger than 5 years) suggests that insecticide-treated nets
prevented 1 in 20 child deaths at that time.
Interpretation: Social Marketing of
insecticide-treated nets has great potential for effective malaria control
in rural African settings.
Acta Trop 2001 Mar 30;78(3):191-206
Critical issues in the economic evaluation of interventions against
Hutubessy RC, Bendib LM, Evans DB.
The Global Programme on Evidence for Health Policy, World Health
Organization, 20 Avenue Appia, CH-1211 27, Geneva, Switzerland
Economic appraisal seeks to provide policy-makers with guidance about
how scarce resources can be used to derive the greatest possible
social benefit. Its use in the health sector has increased
dramatically over the last decade although much of it has been focused
on the problems of the more developed countries. The relatively sparse
literature on communicable diseases has been dominated by
interventions related to HIV/AIDS, hepatitis, malaria and tropical
diseases. Reviews of this literature from the perspective of specific
conditions such as Hepatitis B are already available, and recently the
entire literature has been evaluated against the technical criteria
for economic evaluations published in standard textbooks. Accordingly,
this paper focuses on issues which would make economic appraisal more
useful to policy-makers than it currently is. Given that few countries
have the resources to undertake all the necessary analysis in their
own settings, it is important that studies in one setting are
undertaken in a way that allow generalisability to similar settings.
Some of the most important challenges this poses for
cost-effectiveness analysis (CEA) are identified. Firstly, incremental
analysis is appropriate to local decision making when policy-makers
are constrained to keep the current interventions and can consider
only marginal improvements. However, it does not allow re-evaluation
of existing interventions and is not transferable across settings. A
version of Generalised CEA is proposed as an alternative. Secondly,
data on costs and effectiveness are often not presented appropriately.
The challenge for effectiveness is to adjust the evidence from
efficacy studies to allow for different patient or population groups,
and local variations in adherence, coverage, and infrastructure. For
costs, it is important for studies to report the physical resources
used in an intervention as well as unit prices. Thirdly, some
long-term effects are still not well incorporated into CEA, especially
those affecting child development and drug resistance. These questions
are technically challenging and require more concerted efforts over
the next few years. Finally, it is important for analysts to provide
decision-makers with estimates of the resources that would be required
to implement interventions claimed to be cost-effective. These
improvements would better enable the evidence from economic analyses
to enter the policy debate and be weighed against the other goals and
objectives of the health system when allocating scarce resources.
PMID: 11311183 [PubMed - in process]
J Infect Dis 2001 May
Induces a Th1/Th2 Disequilibrium, Favoring the Th1-Type Pathway, in the
Fievet N, Moussa M, Tami G, Maubert B, Cot M, Deloron P, Chaouat G.
Research Unit 10, Mother and Child Health in the Tropics, Institut de
Recherche pour le Developpement, Paris, France and Organisation de
Coodination pour la Lutte contre les Endemies en Afrique Centrale, Yaounde,
During pregnancy, a local and systemic Th2 bias of maternal immunity
favors Th1-dependent infections such as malaria. This study measured
cytokines secreted in cultures of chorionic villi, placental blood cells (PBC),
and serum in term placentas from 88 malaria-infected and -noninfected
Cameroon women. Interleukin (IL)-2 and -4 were consistently low; IL-1beta,
IL-6, granulocyte-macrophage colony-stimulating factor, and transforming
growth factor (TGF)-beta2 were highest in villi cultures. Tumor necrosis
factor (TNF)-alpha, interferon (IFN)-gamma, and IL-10 were highest in PBC
cultures. Malaria placental infection increased Th1-type cytokines,
whereas Th2-type cytokines and TGF-beta2 were unchanged. Addition of
lipopolysaccharide or infected erythrocytes to cultures increased TNF-alpha,
IL-1beta, IL-6, and IL-10 secretions but not those of IFN-gamma and IL-4.
Overall, Plasmodium falciparum induced a placental immune response
involving both Th1- and Th2-type cell activation. Although the Th1 pathway
was favored, IL-10 secretion was also increased, and this increase should
be effective in protecting the placenta by controlling the negative
effects of Th1 cytokines on pregnancy.
Biometrics 1999 Jun;55(2):565-73
Stochastic algorithms for Markov
models estimation with intermittent missing data.
Deltour I, Richardson S, Le Hesran JY.
INSERM U.170, Villejuif, France.
Multistate Markov models are frequently used to characterize disease
processes, but their estimation from longitudinal data is often
hampered by complex patterns of incompleteness. Two algorithms for
estimating Markov chain models in the case of intermittent missing
data in longitudinal studies, a stochastic EM algorithm and the Gibbs
sampler, are described. The first can be viewed as a random
perturbation of the EM algorithm and is appropriate when the M step is
straightforward but the E step is computationally burdensome. It leads
to a good approximation of the maximum likelihood estimates. The Gibbs
sampler is used for a full Bayesian inference. The performances of the
two algorithms are illustrated on two simulated data sets. A
motivating example concerned with the modelling of the evolution of
parasitemia by Plasmodium falciparum (malaria) in a cohort of 105
young children in Cameroon is described and briefly analyzed.
PMID: 11318215 [PubMed - in process]
Cent Afr J Med 2000 Jul;46(7):190-4
The efficacy and residual life span
of two alphacypermethrin insecticide formulations (Fendona 6%
suspension concentrate and Fendona Dry 15%) treated on mosquito bed
Chirebvu E, Nzira L.
De Beers Research Laboratory, P O Box 197, Chiredzi, Zimbabwe. [email protected]
OBJECTIVE: To compare the effects of mosquito nets treated with two
formulations of alpha-cypermethrin insecticide with a view to
recommending the most appropriate formulation for use to treat
mosquito nets. DESIGN: Assessment of insecticide potency under
conditions of ordinary use. SETTING: Chilonga rural irrigation
community in south east Lowveld Zimbabwe, a holoendemic area of year
round malaria transmission. SUBJECTS: Convenience sample of 20
household heads (volunteers) was issued with treated mosquito nets.
INTERVENTION: Following mosquito net treatment and distribution,
bioassay tests were carried out monthly for a period of six months on
insecticide and placebo treated nets. Questionnaires were administered
once, one month post treatment of nets. MAIN OUTCOME MEASURES: Median
mosquito knock down times of mosquitoes exposed to insecticide treated
nets and community attitude towards the use of insecticide treated
nets. RESULTS: Average time taken to knock down the median mosquito
progressed from 2.3 minutes to 13.0 minutes for Fendona Dry 15% and
from 4.1 minutes to 7.8 minutes for Fendona 6% SC over the six month
period. The average time taken to knock down the median mosquito three
months post-washing were 13.0 minutes and 7.4 minutes for Fendona Dry
15% and Fendona 6% SC respectively as against more than 30 minutes in
controls. Both insecticides exhibited some wash resistance properties.
The side effects reported were sneezing, itching, skin rash and
smelling. Questionnaire data suggested that alphacypermethrin treated
mosquito nets were welcomed. CONCLUSIONS: Both insecticide
formulations proved to be suitable candidates. This was because of
their insecticidal potency, wash resistance properties and acceptance
by the community.
PMID: 11317588 [PubMed - in process]
Cent Afr J Med 2000 Jul;46(7):174-8
Urban malaria transmission in Mutare
City; an unlikely phenomenon.
Masendu HT, McClean D, Mushavave ST, Chinyowa D, Simbanegavi P,
Chawarika C, Ndlovu F.
Mutare City Health Department, Civic Centre, P O Box 910, Mutare.
OBJECTIVE: With an average altitude of 1,113 m above sea level and a
mean maximum temperature of 28.6 degrees C, malaria transmission is
possible in Mutare. Against transmission is the regular occurrence of
ground frost. We reviewed epidemiological data and undertook a survey
for the Anopheles vector. DESIGN: The Anopheles survey used standard
techniques for sampling larvae and adult mosquitoes. Species
identification was done by the polymerase chain reaction (PCR)
technique. A random sample of blood slides was examined at the Blair
Laboratory. Patient residence was determined from the outpatient
register. Daily maximum and minimum temperatures monitored from the
Mutare Fire Station, were obtained from the Meteorology Office in
Harare. SETTING: Mutare city and suburbs. RESULTS: There was no
evidence of rising temperatures in Mutare. Only non-vector Anopheles
mosquitoes were identified (An. quadriannulatus and An. pretoriensis).
One slide positive case had gametocytes present. Mapping generally
showed no clustering, but there were two possible transmission foci.
CONCLUSION: Temperatures are high enough, but winter lows (< 18
degrees C) do not support malaria transmission in Mutare. The
Anopheles survey did not find the vector. Two suggestive clusters were
mapped. While present data do not support ongoing malaria transmission
within Mutare, in the past, An. gambiae, An. fenestus and An.
pretoriensis were recorded. Careful monitoring will be needed.
PMID: 11317585 [PubMed - in process]
Parasitology 2001 Apr;122(Pt 4):379-91
Plasmodium falciparum parasitaemia
described by a new mathematical model.
Molineaux L, Diebner HH, Eichner M, Collins WE, Jeffery GM, Dietz
Department of Medical Biometry, University of Tubingen, Germany.
A new mathematical model of Plasmodium falciparum asexual parasitaemia
is formulated and fitted to 35 malaria therapy cases making a
spontaneous recovery after primary inoculation. Observed and simulated
case-histories are compared with respect to 9 descriptive statistics.
The simulated courses of parasitaemia are more realistic than any
previously published. The model uses a discrete time-step of 2 days.
Its realistic behaviour was achieved by the following combination of
features (i) intra-clonal antigenic variation, (ii) large variations
of the variants' baseline growth rate, depending on both variant and
case, (iii) innate autoregulation of the asexual parasite density,
variable among cases, (iv) acquired variant-specific immunity and (v)
acquired variant-transcending immunity, variable among cases. Aspects
of the model's internal behaviour, concerning variant dynamics, as
well as the respective contributions of the three control mechanisms
(iii) - (v), are displayed. Some implications for pathogenesis and
control are discussed.
PMID: 11315171 [PubMed - in process]
Mem Inst Oswaldo Cruz 2001 Apr;96(3):427-33
Genome comparison of progressively
drug resistant Plasmodium falciparum lines derived from drug sensitive
Toteja R, Nair L, Bhasin V.
Department of Zoology, University of Delhi, Delhi, India.
Chloroquine has been the mainstay of malaria chemotherapy for the past
five decades, but resistance is now widespread. Pyrimethamine or
proguanil form an important component of some alternate drug
combinations being used for treatment of uncomplicated Plasmodium
falciparum infections in areas of chloroquine resistance. Both
pyrimethamine and proguanil are dihydrofolate reductase (DHFR)
inhibitors, the proguanil acting primarily through its major
metabolite cycloguanil. Resistance to these drugs arises due to
specific point mutations in the dhfr gene. Cross resistance between
cycloguanil and pyrimethamine is not absolute. It is, therefore,
important to investigate mutation rates in P. falciparum for
pyrimethamine and proguanil so that DHFR inhibitor with less mutation
rate is favored in drug combinations. Hence, we have compared mutation
rates in P. falciparum genome for pyrimethamine and cycloguanil. Using
erythrocytic stages of P. falciparum cultures, progressively drug
resistant lines were selected in vitro and comparing their RFLP
profile with a repeat sequence. Our finding suggests that
pyrimethamine has higher mutation rate compared to cycloguanil. It
enhances the degree of genomic polymorphism leading to diversity of
natural parasite population which in turn is predisposes the parasites
for faster selection of resistance to some other antimalarial drugs.
PMID: 11313656 [PubMed - in process]
Blood 2001 May 1;97(9):2879-2885
Molecular identification of Knops
blood group polymorphisms found in long homologous region D of
complement receptor 1.
Moulds JM, Zimmerman PA, Doumbo OK, Kassambara L, Sagara I, Diallo
DA, Atkinson JP, Krych-Goldberg M, Hauhart RE, Hourcade DE, McNamara
DT, Birmingham DJ, Rowe JA, Moulds JJ, Miller LH.
University of Texas-Houston Medical School, Houston; Case Western
Reserve University, Cleveland, OH; University of Mali, Bamako, Mali;
Washington University School of Medicine, St. Louis, MO; The Ohio
State University, Columbus; University of Edinburgh, Scotland; Ortho
Clinical Diagnostics, Raritan, NJ; and National Institutes of Health,
National Institute of Allergy and Infectious Diseases, Bethesda, MD.
Complement receptor 1 (CR1) has been implicated in rosetting of
uninfected red blood cells to Plasmodium falciparum-infected cells,
and rosette formation is associated with severe malaria. The Knops
blood group (KN) is located on CR1 and some of these antigens, ie,
McCoy (McC) and Swain-Langley (Sl(a)), show marked frequency
differences between Caucasians and Africans. Thus, defining the
molecular basis of these antigens may provide new insight into the
mechanisms of P falciparum malaria. Monoclonal antibody epitope
mapping and serologic inhibition studies using CR1 deletion constructs
localized McC and Sl(a) to long homologous repeat D of CR1. Direct DNA
sequencing of selected donors identified several single nucleotide
polymorphisms in exon 29 coding for complement control protein modules
24 and 25. Two of these appeared to be blood group specific: McC
associated with K1590E and Sl(a) with R1601G. These associations were
confirmed by inhibition studies using allele-specific mutants. A
sequence-specific oligonucleotide probe hybridization assay was
developed to genotype several African populations and perform family
inheritance studies. Concordance between the 1590 mutation and McC was
94%; that between Sl(a) and 1601 was 88%. All but 2 samples exhibiting
discrepancies between the genotype and phenotype were found to be due
to low red cell CR1 copy numbers, low or absent expression of some
alleles, or heterozygosity combined with low normal levels of CR1.
These data further explain the variability observed in previous
serologic studies of CR1 and show that DNA and protein-based genetic
studies will be needed to clarify the role of the KN antigens in
malaria. (Blood. 2001;97:2879-2885)
PMID: 11313284 [PubMed - as supplied by publisher]
Sante 2001 Jan-Feb;11(1):25-33
The number of deaths attributable to
malaria in the Niakhar area, Senegal, from 1984 to 1996
Ndiaye O, Hesran JY, Etard JF, Diallo A, Simondon F, Ward MN,
Institut de recherche pour le developpement, BP 1386, Dakar, Senegal.
There are a number of reasons why climate, in certain physical and
social environments, could have an impact on the epidemiology of
malaria. Events, such as floods or drought, are related to the number
of malaria cases and deaths, both seasonally and interannually. At a
smaller scale, this study analyses the relation between climate
variability and the variability in the number of deaths attributable
to malaria in Niakhar, Senegal. The Niakhar area has a population of
30,000 and has been under demographic surveillance system since 1984.
The rainfall in this region is highly seasonal, with a rainfall
maximum in August and almost no rain between October/November and
May/June. In addition to this seasonal cycle, rainfall also varies
greatly from year to year (interannual variation). Over the 13 years,
there were 661 deaths attributed to malaria with a marked interannual
variability (range from 23 to 100, with a median of 43). There was
also a strong seasonality in mortality, with nearly all deaths (89.1%)
occurring between August and December. The number of deaths peaks in
October, two months after the rainfall peak. Standardised monthly
values were calculated for each climatic series (rainfall, relative
humidity, temperature) as well as standardised five-month and monthly
values of the number of deaths attributed to malaria between August
and December. Correlation coefficients were calculated between these
standardised values. The correlation between the variability in August
rainfall and the variability in the number of deaths attributed to
malaria between August and December was positive and statistically
significant (r = +0.61, p = 0.02). In addition, highly significant
cross-correlations were found between monthly rainfall series and
monthly mortality series at one- and two-month lag (r = + 0.43, p =
0.0004 for one-month lag; r = + 0.26, p = 0.03 for two-month lag).
This correlation is somewhat lower than the correlation of August
rainfall alone with August to December mortality, but the result adds
confidence to the signal given the increased degrees of freedom in the
analysis. Similar, but slightly weaker, results were found when
precipitation data were replaced with surface humidity data. Results
with temperature were less clear; while temperature could in some
circumstances have a direct impact on malaria, in this case here it is
possible that the weak negative correlation between malaria deaths and
temperature arises mainly because precipitation is physically
connected to both the indices, correlating positively with malaria and
negatively with temperature. The availability of a continuous
demographic and medical survey since 1984 in a region of highly
variable rainfall has created a rare opportunity to analyse with some
confidence a climate versus malaria relationship. The findings are
consistent with our understanding of the proposed link between
rainfall and conditions for the reproduction of the malaria vector,
leading to a lag time (here of one to two months) between anomalies of
rainfall and deaths attributable to malaria. These results may have
practical implications in Sub-Saharan regions marked by a great
seasonal and interannual variability in rainfall by providing a simple
tool to forecast the impact of climate variability on malaria
PMID: 11313229 [PubMed - in process]
Food Chem Toxicol 2001 May;39(5):407-22
Risk assessment of the use of
deltamethrin on bednets for the prevention of malaria.
Barlow SM, Sullivan FM, Lines J.
Consultants in Toxicology, Harrington House, 8 Harrington Road, East
Sussex BN1 6RE, Brighton, UK
Risk assessments covering the use of the pyrethroid, deltamethrin, on
bednets for the prevention of malaria have been conducted The toxicity
of deltamethrin in humans and animals is reviewed following both
dermal and oral exposure. The no-adverse-effect level (NOEL) for
exposure via the dermal route was 1000 mg/kg body weight/day. From
this an acceptable exposure level (AEL) of 10 mg/kg body weight/day
has been derived. The NOEL for exposure via the oral route was 1 mg/kg
body weight/day, with exposures above this causing neurotoxic effects
in animals. This NOEL has been used to derive margins of safety
compared with predicted exposures. While direct skin contact does not
seem to cause systemic toxicity in humans, it can cause burning,
numbness and tingling of the skin, which is a local effect. This too
is taken into account in the risk assessments. The risk assessments
cover those treating bednets, on an intermittent or regular basis, the
washing of treated nets, sleeping under treated nets (infants,
children and adults). Worst case scenarios for each of these
situations show that dermal exposures are low (one-tenth or less of
the AEL) and the margins of safety for systemic exposure derived from
oral data are acceptable, ranging from 10 to 3300. The benefits of the
use of treated bednets in reducing morbidity and mortality from
malaria are considerable and it can be concluded that the risk:benefit
ratio is very favourable.
PMID: 11313107 [PubMed - in process]
Exp Parasitol 2001 Mar;97(3):119-28
Primary Structure of the Plasmodium
vivax crk2 Gene and Interference of the Yeast Cell Cycle upon Its
Speranca MA, Vinkenoog R, Ocampos M, Fischer K, Janse CJ, Waters
AP, del Portillo HA.
Departamento de Parasitologia, Instituto de Ciencias Biomedicas, Sao
Paulo, SP, 05508-900, Brazil
Speranca, M. A., Vinkenoog, R., Ocampos, M., Fischer, K., Janse, C.
J., Waters, A. P., and del Portillo, H. A. 2001. Primary structure of
the Plasmodium vivax crk2 gene and interference of the yeast cell
cycle upon its conditional expression. Experimental Parasitology 97,
119-128. The cdc2 gene product, a 34-kDa protein kinase, plays a
universal role in the M phase of the eukaryotic cell cycle. To study
the cell cycle regulation in malarial parasites, we have characterized
a cdc2-related gene from the most widely distributed human malaria,
Plasmodium vivax (Pvcrk2). The full-length Pvcrk2 revealed 90-99%
homology with Crk2 proteins from other Plasmodium species and
approximately 60% homology with p34(cdc2) proteins from higher
eukaryotes. We used the temperature-sensitive Schizosaccharomyces
pombe cdc2 mutant (cdc2-33(ts)) for gene complementation studies.
Expression of the full-length 33-kDa PvCrk2 protein, a truncated
27-kDa version, and two chimeric proteins in which we exchanged the N-
and C-terminal regions of PvCrk2 with their S. pombe counterparts at
the restrictive temperature in the mutant cdc2-33(ts) did not
complement the cell cycle defect. However, conditional expression of
the Pvcrk2 genes or the chimera containing the C terminus from Spcdc2
in mutant cdc2-33(ts) cells produced cell-cycle-arrested phenotypes
only in the induced state and at the permissive temperature. Our
results thus provide the first compelling genetic evidence that the
plasmodial Crk2 gene product(s) is capable of interfering with the
well-conserved eukaryotic cell cycle machinery. Copyright 2001
PMID: 11312574 [PubMed - in process]
Biochem J 2001 May 1;355(Pt 3):733-9
Transport of lactate and pyruvate in the intraerythrocytic malaria
parasite, Plasmodium falciparum.
Elliott JL, Saliba KJ, Kirk K.
School of Biochemistry and Molecular Biology, Faculty of Science,
Australian National University, Canberra, A.C.T. 0200, Australia.
The mature, intraerythrocytic form of the human malaria parasite,
Plasmodium falciparum, is reliant on glycolysis for its energetic
requirements. It produces large quantities of lactic acid, which have
to be removed from the parasite's cytosol to maintain the cell's
integrity and metabolic viability. Here we show that the
monocarboxylates lactate and pyruvate are both transported across the
parasite's plasma membrane via a H(+)/monocarboxylate symport process
that is saturable and inhibited by the bioflavonoid phloretin. The
results provide direct evidence for the presence at the parasite
surface of a H(+)-coupled monocarboxylate transporter with features in
common with members of the MCT (monocarboxylate transporter) family of
PMID: 11311136 [PubMed - in process]
Bioorg Med Chem 2001 Mar;9(3):785-92
Discovery of a novel lead structure for anti-malarials.
Wiesner J, Wissner P, Dahse HM, Jomaa H, Schlitzer M.
Biochemisches Institut der Universitatsklinik Giessen, Germany.
From a library of 61 compounds available from former studies
2,5-bis-acylaminobenzophenone 7p was identified as a lead structure
for a novel class of anti-malaria agents active against
multi-resistant Plasmodium falciparum strain Dd2. Some structural
modifications of this initial lead demonstrated the potential for
further improvement of the anti-plasmodial activity of this novel
class of anti-malarials.
PMID: 11310613 [PubMed - in process]
J Assoc Physicians India 2000 Nov;48(11):1085-6
Relapse pattern of Plasmodium vivax in Mumbai: a study of 283 cases
of vivax malaria.
Gogtay NJ, Desai S, Kadam VS, Kamtekar KD, Dalvi SS, Kshirsagar NA.
Department of Clinical Pharmacology, BYL Nair Ch Hospital & TN
Medical College, Mumbai 400 008.
OBJECTIVES: To analyze the relapse pattern of Plasmodium vivax in the
city of Mumbai. METHODS: 283 cases of smear positive vivax malaria
were treated with full dose (25 mg/kg) chloroquine and were asked to
follow up for at least one year. None of the patients received
primaquine. RESULTS: Of the 150 cases who followed up for at least one
year, 19 relapsed, 17/19 relapsed within the first 6 months;
indicating that the relapse pattern in the city is predominantly of
the tropical or Chesson strain type. CONCLUSIONS: Vivax malaria
patients should be monitored for at least six months. Those who do
relapse should receive treatment with full dose chloroquine and 14
days of primaquine treatment.
PMID: 11310387 [PubMed - in process]
J Clin Apheresis 2001;16(1):15-8
Erythrocytapheresis for Plasmodium falciparum infection complicated
by cerebral malaria and hyperparasitemia.
Zhang Y, Telleria L, Vinetz JM, Yawn D, Rossmann S, Indrikovs AJ.
Department of Pathology, Blood Bank Division, University of Texas
Medical Branch, Galveston, Texas.
In malaria due to Plasmodium falciparum, life-threatening
complications are in part related to the degree of parasitemia. Whole
blood exchange and red blood cell exchange (RCE) have been used for
the rapid removal of parasites from the circulation of patients with a
high parasite load complicated by cerebral, pulmonary, and renal
dysfunction. We have treated three 5-45-year-old patients with
hyperparasitemia and end-organ dysfunction with red cell exchange by
automated apheresis as an adjunct to specific anti-malarial
chemotherapy. Parasitemia dropped more than 80% in all three patients
immediately after the exchange, and all patients had an uneventful and
full recovery. In combination with effective anti-malarial
chemotherapy, apheresis RCE is a safe and rapid approach to treat
complicated malaria due to P. falciparum. J. Clin. Apheresis.
16:15-18, 2001. Copyright 2001 Wiley-Liss, Inc.
PMID: 11309825 [PubMed - in process]
Proc Natl Acad Sci U S A 2001 Apr 24;98(9):5228-5233
Anti-mosquito midgut antibodies block development of Plasmodium
falciparum and Plasmodium vivax in multiple species of Anopheles
mosquitoes and reduce vector fecundity and survivorship.
Lal AA, Patterson PS, Sacci JB, Vaughan JA, Paul C, Collins WE,
Wirtz RA, Azad AF.
Division of Parasitic Diseases, National Center for Infectious
Diseases, Centers for Disease Control and Prevention, Chamblee, GA
30341; Department of Microbiology and Immunology, University of
Maryland, 655 West Baltimore Street, Baltimore, MD 21201; and Malaria
Program, Naval Medical Research Center, 503 Robert Grant Avenue,
Silver Spring, MD 20910.
The mosquito midgut plays a central role in the sporogonic development
of malaria parasites. We have found that polyclonal sera, produced
against mosquito midguts, blocked the passage of Plasmodium falciparum
ookinetes across the midgut, leading to a significant reduction of
infections in mosquitoes. Anti-midgut mAbs were produced that display
broad-spectrum activity, blocking parasite development of both P.
falciparum and Plasmodium vivax parasites in five different species of
mosquitoes. In addition to their parasite transmission-blocking
activity, these mAbs also reduced mosquito survivorship and fecundity.
These results reveal that mosquito midgut-based antibodies have the
potential to reduce malaria transmission in a synergistic manner by
lowering both vector competence, through transmission-blocking effects
on parasite development, and vector abundance, by decreasing mosquito
survivorship and egg laying capacity. Because the intervention can
block transmission of different malaria parasite species in various
species of mosquitoes, vaccines against such midgut receptors may
block malaria transmission worldwide.
PMID: 11309510 [PubMed - as supplied by publisher]
Parasite Immunol 2001 May;23(5):267-9
CD1d-restricted NK T cells are dispensable for specific antibody
responses and protective immunity against liver stage malaria
infection in mice.
Romero JF, Eberl G, MacDonald Hr, Corradin G.
Institute of Biochemistry and Ludwig Institute for Cancer Research,
Lausanne Branch, University of Lausanne, Epalinges, Switzerland.
Immunization with a single dose of irradiated sporozoites is
sufficient to induce protection against malaria in wild-type mice.
Although this protection is classically attributed to conventional
CD4+ and CD8+ T cells, several recent reports have suggested an
important role for CD1-restricted NK T cells in immunity to malaria.
In this study, we directly compared the ability of C57BL/6 wild-type
and CD1-deficient mice to mount a protective immune response against
Plasmodium berghei sporozoites. Our data indicate that CD1-restricted
NK T cells are not required for protection in this model system.
Moreover, specific IgG antibody responses to the P. berghei
circumsporozoite repeat sequence were also unaffected by CD1
deficiency. Collectively, our data demonstrate that CD1-restricted NK
T cells are dispensable for protective immunity to liver stage P.