Population Dynamics of Malaria Vectors in Western Kenya Highlands

Ndenga, Bryson; Githeko, Andrew K.; Omukunda, Elizabeth; Munyekenye, Godwil; Atieli, Harrysonne; Wamai, Peter; Mbogo, Charles M.; Minakawa, Noboru; Zhou, Guobing; Yan, Guiyun

doi:10.1603/0022-2585(2006)043[0200:pdomvi]2.0.co;2

Cited by 78 publications

(61 citation statements)

References 34 publications

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“…This study was conducted at the antenatal clinic (ANC) and maternity ward of Chulaimbo Sub-District Hospital in Kisumu West District. This hospital mainly serves a rural population that experiences holoendemic malaria with two seasonal peaks: June to August and November to December (28). The inclusion criteria specified pregnant women of any gravidity, gestation for Ͻ24 weeks, having a normal full blood count, HIV-negative status, residency within a 10-km distance of the hospital, and willingness to return to the hospital for delivery, follow-up clinical procedures, and laboratory testing.…”

Section: Methodsmentioning

confidence: 99%

Reduced Transplacental Transfer of a Subset of Epstein-Barr Virus-Specific Antibodies to Neonates of Mothers Infected with Plasmodium falciparum Malaria during Pregnancy

Ogolla

Daud

Asito

et al. 2015

Clin Vaccine Immunol

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h Over 35% of children in a region of malaria endemicity are infected with Epstein-Barr virus (EBV) by 6 months of age. This susceptibility may be linked to impaired transplacental transfer of antibodies. In this study, we determined the effect of malaria exposure during pregnancy on the transfer of EBV-specific maternal antibodies in a region of western Kenya that experiences endemic malaria. Pregnant mothers were recruited and followed up until delivery to determine levels of neonatal malaria exposure. Levels of EBV lytic (viral capsid antigen [VCA], Z transcriptional activator [Zta], and early diffuse antigen complex [EAd]) and EBV latent (EBV nuclear antigen-1 (EBNA1]) and tetanus-specific IgG antibodies were measured in 70 paired maternal and cord blood samples using a Luminex-bead-based assay. A high proportion (63%) of the infants were exposed to malaria in utero. Levels of EBV-and tetanus-specific antibodies were similar in malaria-infected mothers and in mothers who had no detectable malaria infection. Malaria-exposed neonates had significantly lower levels of anti-EBNA1, anti-Zta, and anti-EAd antibodies than were seen in their mothers. In utero malaria exposure resulted in significant reductions in transplacental transfer of anti-VCA-p18 and anti-EBNA1 antibodies of 13% and 22%, respectively. Neonates received significantly low levels of anti-Zta and anti-EAd antibodies irrespective of malaria exposure levels. In multivariate analysis, in utero malaria exposure was associated with a significant reduction in the transfer of anti-VCA-p18 and anti-EBNA1 antibodies to the neonates (P ‫؍‬ 0.0234 and P ‫؍‬ 0.0017, respectively). Malaria during pregnancy results in differential levels of transfer of EBV-specific antibodies from the mother to the fetus. The impaired transplacental transfer of some antibodies may lead to the malaria-exposed neonates being susceptible to early EBV infection. E ndemic Burkitt's lymphoma (eBL) is a distinct form of nonHodgkin's lymphoma and is the most common pediatric malignancy in regions of malaria endemicity of sub-Saharan Africa (1). Both infection with Epstein-Barr virus (EBV) and repeated episodes of Plasmodium falciparum malaria are known risk factors for eBL (2), but the mechanism(s) by which these two agents interact to promote the emergence of malignant B cell clones has not been elucidated. Recently, we found that infants from a region of malaria endemicity of western Kenya were infected with EBV by 6 months of age (3). Living in regions of malaria endemicity was a predictor of this early age of primary infection. This aberrant primary EBV infection may set the stage for lymphoma development, as previously hypothesized (4-6).The lytic and latent phases of the EBV life cycle induce distinct antibodies in response to specific lytic and latent antigens. Anti-EBV nuclear antigen-1 (EBNA1) antibodies are produced against EBNA1, the only antigen expressed in latently infected memory B cells and in eBL tumors (7). Anti-viral capsid antigen (anti-VCA), anti-early antigen (ant...

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Section: Methodsmentioning

confidence: 99%

Reduced Transplacental Transfer of a Subset of Epstein-Barr Virus-Specific Antibodies to Neonates of Mothers Infected with Plasmodium falciparum Malaria during Pregnancy

Ogolla

Daud

Asito

et al. 2015

Clin Vaccine Immunol

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“…gambiae s.s. was the major vector species driving transmission at one site in the lowlands and three sites in the highlands. 8 However, one of the villages in the lowland site had experienced recent larval habitat changes and An. funestus s.s. was found to be the major vector species.…”

Section: Introductionmentioning

confidence: 99%

“…funestus s.s. was found to be the major vector species. 8 In addition, there was pronounced spatial heterogeneity in vector composition and transmission rates in the lowland areas. 8,9 Differences in vector composition, biting behaviors, and transmission intensities among study sites that also vary temporally and spatially suggest that there is unequal risk of malarial transmission within an endemic area.…”

Section: Introductionmentioning

confidence: 99%

“…8 In addition, there was pronounced spatial heterogeneity in vector composition and transmission rates in the lowland areas. 8,9 Differences in vector composition, biting behaviors, and transmission intensities among study sites that also vary temporally and spatially suggest that there is unequal risk of malarial transmission within an endemic area. Heterogeneity in malarial risk has implications for developing and targeting interventions because a single vector control measure such as indoor residual spraying (IRS) may successfully interrupt transmission in a low transmission setting, whereas multiple vector control measures such as IRS, long-lasting insecticide-treated nets (LLINs), larviciding, and/or larval habitat source reduction may be needed to have an impact in high transmission settings.…”

Section: Introductionmentioning

confidence: 99%

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Habitat Partitioning of Malaria Vectors in Nchelenge District, Zambia

Das

Muleba

Stevenson

et al. 2016

The American Journal of Tropical Medicine and Hygiene

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Abstract. Nchelenge District in Luapula Province, northern Zambia, experiences holoendemic malaria despite implementation of vector control programs. The major Anopheles vectors that contribute to Plasmodium falciparum transmission in this area had not previously been well defined. Three collections performed during the 2012 wet and dry seasons and the 2013 wet season revealed Anopheles funestus sensu stricto and Anopheles gambiae sensu stricto as the main vectors, where 80-85% of each collection was composed of An. funestus. Both vectors were found to be highly anthropophilic, and An. funestus has higher sporozoite infection rates (SIRs) and entomological inoculation rates (EIRs) year-round compared with An. gambiae: SIRs of 1.8-3.0% and 0-2.5%, respectively, and EIRs of 3.7-41.5 infectious bites per 6-month period (ib/p/6mo) and 0-5.9 ib/p/6mo, respectively. Spatial and temporal changes in each vector's dynamics and bionomics were also observed. Anopheles funestus was the predominant vector in the villages near Kenani Stream in both wet and dry seasons, whereas An. gambiae was found to be the main vector in areas near Lake Mweru during the wet season. The vector data illustrate the need for broader temporal and spatial sampling in Nchelenge and present unique opportunities to further our understanding of malarial transmission and implications for malarial control in high-risk areas.

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“…23,26 In this study we used a "pre-test/ post-test control group" design to investigate the contributions of both mosquito larval control with microbials and ITNs to reducing the burden of malaria in the Kakamega and Vihiga highlands of western Kenya, an area moderately endemic for the disease. 27 …”

Section: Introductionmentioning

confidence: 99%

Integrated malaria vector control with microbial larvicides and insecticide-treated nets in western Kenya: a controlled trial

Fillinger¹,

Ndenga²,

Githeko³

et al. 2009

Bull World Health Org

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199

294

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Objective To assess the contributions of both microbial larvicides and insecticide-treated nets (ITNs) in terms of reducing malaria incidence in an integrated vector management programme in an area moderately endemic for malaria in the western Kenyan highlands. Methods A pre-post, control group design was used. Larval and adult vector populations were surveyed weekly in six separate valley communities. The incidence of Plasmodium infections in children 6 months to 13 years of age was measured during the long and short rainy seasons each year. Baseline data were collected for 17 months, after which Bacillus-based larvicides were applied weekly to aquatic habitats in three of the valleys for another 19 months. At around the same time the larviciding was initiated, ITNs were introduced gradually into all study communities by the National Malaria Control Programme. The effect of larviciding, ITNs and other determinants of malaria risk was assessed by means of generalized estimating equations. Findings The risk of acquiring new parasite infections in children was substantially and independently reduced by ITN use (odds ratio, OR: 0.69; 95% confidence interval, CI: 0.48-0.99) and larvicide application (OR: 0.44; 95% CI: 0.23-0.82), after adjusting for confounders. Conclusion Vector control with microbial larvicides enhanced the malaria control achieved with ITNs alone. Anti-larval measures are a promising complement to ITN distribution in the economically important highland areas and similar transmission settings in Africa.Une traduction en français de ce résumé figure à la fin de l'article. Al final del artículo se facilita una traducción al español. ‫املقالة.‬ ‫لهذه‬ ‫الكامل‬ ‫النص‬ ‫نهاية‬ ‫يف‬ ‫الخالصة‬ ‫لهذه‬ ‫العربية‬ ‫الرتجمة‬

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Population Dynamics of Malaria Vectors in Western Kenya Highlands

Cited by 78 publications

References 34 publications

Reduced Transplacental Transfer of a Subset of Epstein-Barr Virus-Specific Antibodies to Neonates of Mothers Infected with Plasmodium falciparum Malaria during Pregnancy

Reduced Transplacental Transfer of a Subset of Epstein-Barr Virus-Specific Antibodies to Neonates of Mothers Infected with Plasmodium falciparum Malaria during Pregnancy

Habitat Partitioning of Malaria Vectors in Nchelenge District, Zambia

Integrated malaria vector control with microbial larvicides and insecticide-treated nets in western Kenya: a controlled trial

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