Seasonal patterns of Plasmodium falciparum gametocyte prevalence and density in a rural population of Burkina Faso

Ouédraogo, André Lin; Vlas, Sake J. de; Nébié, Issa; Ilboudo-Sanogo, Edith; Bousema, Teun; Ouattara, Aboubakar S.; Verhave, J.P.; Cuzin-Ouattara, N.; Sauerwein, Robert W.

doi:10.1016/j.actatropica.2007.09.003

Cited by 39 publications

(39 citation statements)

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“…This occurs after limited exposure to gametocytes in the youngest age groups, but boosting is also evident during the peak of the transmission season. A next step would be to determine the functional importance of sexual stage-specific antibody responses in this population, which, despite developing both asexual and sexual stage-specific antibody responses, is repeatedly exposed to intense transmission (35,36).…”

Section: Discussionmentioning

confidence: 99%

Naturally Acquired Immune Responses to Plasmodium falciparum Sexual Stage Antigens Pfs48/45 and Pfs230 in an Area of Seasonal Transmission

et al. 2011

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Acquisition of immunity to Plasmodium falciparum sexual stages is a key determinant for reducing humanmosquito transmission by preventing the fertilization and the development of the parasite in the mosquito midgut. Naturally acquired immunity against sexual stages may therefore form the basis for the development of transmission-blocking vaccines, but studies conducted to date offer little in the way of consistent findings. Here, we describe the acquisition of antigametocyte immune responses in malaria-exposed individuals in Burkina Faso. A total of 719 blood samples were collected in a series of three cross-sectional surveys at the start, peak, and end of the wet season. The seroprevalence of antibodies with specificity for the sexual stage antigens Pfs48/45 and Pfs230 was 2-fold lower (22 to 28%) than that for an asexual blood stage antigen glutamate-rich protein (GLURP) (65%) or for the preerythrocytic stage antigen circumsporozoite protein (CSP) (54%). The youngest children responded at frequencies similar to those for all four antigens but, in contrast with the immune responses to GLURP and CSP that increased with age independently of season and area of residence, there was no evidence for a clear age dependence of responses to Pfs48/45 and Pfs230. Anti-Pfs230 antibodies were most prevalent at the peak of the wet season (P < 0.001). Our findings suggest that naturally acquired immunity against Pfs48/45 and Pfs230 is a function of recent exposure rather than of cumulative exposure to gametocytes.

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Section: Discussionmentioning

confidence: 99%

Naturally Acquired Immune Responses to Plasmodium falciparum Sexual Stage Antigens Pfs48/45 and Pfs230 in an Area of Seasonal Transmission

et al. 2011

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“…Prevalence of gametocytes in different transmission settings and age groups. Gametocytes were detected by microscopy (thick blood films; screening of 100 fields at a magnification of ϫ1,000, using oil immersion) in cross-sectional surveys in areas of high and seasonal transmission intensity in Burkina Faso (336) and the Gambia (121), high perennial transmission in Tanzania (121), and low seasonal transmission intensity in Tanzania (413). Gametocytes are detected in a larger proportion of the population in settings of high endemicity, where gametocyte prevalence depends on age; in settings of low endemicity, gametocyte carriage is rare and more evenly distributed across age groups.…”

Section: What Triggers the Sexual Pathway?mentioning

confidence: 99%

“…Malaria infections and symptomatic malaria episodes are most frequent in the transmission season, usually when mosquitoes are most abundant (following seasonal rains) (321,336). Two longitudinal studies in areas of markedly different transmission characteristics in Burkina Faso indicated that patterns of gametocyte carriage followed that of asexual parasites, increasing during the peak transmission season (44).…”

Section: Gametocyte Carriage In Relation To Season and Transmission Imentioning

confidence: 99%

Epidemiology and Infectivity of Plasmodium falciparum and Plasmodium vivax Gametocytes in Relation to Malaria Control and Elimination

2011

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SUMMARY Malaria remains a major cause of morbidity and mortality in the tropics, with Plasmodium falciparum responsible for the majority of the disease burden and P. vivax being the geographically most widely distributed cause of malaria. Gametocytes are the sexual-stage parasites that infect Anopheles mosquitoes and mediate the onward transmission of the disease. Gametocytes are poorly studied despite this crucial role, but with a recent resurgence of interest in malaria elimination, the study of gametocytes is in vogue. This review highlights the current state of knowledge with regard to the development and longevity of P. falciparum and P. vivax gametocytes in the human host and the factors influencing their distribution within endemic populations. The evidence for immune responses, antimalarial drugs, and drug resistance influencing infectiousness to mosquitoes is reviewed. We discuss how the application of molecular techniques has led to the identification of submicroscopic gametocyte carriage and to a reassessment of the human infectious reservoir. These components are drawn together to show how control measures that aim to reduce malaria transmission, such as mass drug administration and a transmission-blocking vaccine, might better be deployed.

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“…These studies suggest that selection of drug-resistant parasite clones may be associated with increased chances of transmission; however, this hypothesis has yet to be systematically tested given the complex relationship between drug resistance and malaria transmission, which involves factors such as multiplicity of resistant clones, transmission intensity, and the genetic nature of resistance traits (Talisuna et al 2003). Several other conditions have been associated with increased gametocyte production, including the time during transmission season (Ouédraogo et al 2008), response to mosquito probing or bites from uninfected mosquitoes , and presence of vector-borne factors in the blood (Fischer et al 2000).…”

Section: Mechanisms Of Sexual Commitment and Gametocyte Sequestrationmentioning

confidence: 99%

Biology of Malaria Transmission

Meibalan

Marti

2016

Cold Spring Harb Perspect Med

141

137

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Understanding transmission biology at an individual level is a key component of intervention strategies that target the spread of malaria parasites from human to mosquito. Gametocytes are specialized sexual stages of the malaria parasite life cycle developed during evolution to achieve crucial steps in transmission. As sexual differentiation and transmission are tightly linked, a deeper understanding of molecular and cellular events defining this relationship is essential to combat malaria. Recent advances in the field are gradually revealing mechanisms underlying sexual commitment, gametocyte sequestration, and dynamics of transmissible stages; however, key questions on fundamental gametocyte biology still remain. Moreover, species-specific variation between Plasmodium falciparum and Plasmodium vivax transmission dynamics pose another significant challenge for worldwide malaria elimination efforts. Here, we review the biology of transmission stages, highlighting numerous factors influencing development and dynamics of gametocytes within the host and determinants of human infectiousness. C urrent measures for malaria elimination have been inspired by the Global Malaria Eradication Program (GMEP), which operated under the World Health Organization (WHO) between 1955 and 1969. The strategy of GMEP was largely based on dichlorodiphenyltrichloroethane (DDT)-based indoor residual spraying (DDT-IRS) complemented with mass drug administration (Pampana 1969). Although GMEP was able to eliminate malaria from many regions of the world, it was eventually abandoned because of technical challenges, increasing spread of both insecticide resistance and drug-resistant parasite strains, and lack of continuous political support (Najera et al. 2011 ual parasites and early transmission stages, whereas mature infectious transmission stages are unaffected. To block transmission, ACT is often combined with the only transmissionblocking drug on the market, Primaquine. However, recent emergence of artemisinin resistance in Southeast Asia asks for urgent evaluation of alternative treatment strategies (Noedl et al. 2008;Dondorp et al. 2009;Mbengue et al. 2015;Straimer et al. 2015).Of the five Plasmodium species known to cause malaria in humans, Plasmodium falciparum is lethal and responsible for severe disease pathology and the majority of deaths due to malaria, especially in sub-Saharan Africa. Plasmodium vivax typically causes milder infections than P. falciparum but has a much greater geographical distribution (Gething et al. 2012). The clinical symptoms of malaria are largely a result of the replication of asexual stages in human blood, but transmission to mosquitoes is only achieved through the development of sexual stages, termed gametocytes. To abrogate transmission of P. falciparum, we must be able to clear asexual and sexual stages from the human host, eventually rendering an individual noninfectious to mosquitoes. However, in the case of P. vivax, elimination is highly challenging because of the relapse of dormant liver-stage h...

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Seasonal patterns of Plasmodium falciparum gametocyte prevalence and density in a rural population of Burkina Faso

Cited by 39 publications

References 29 publications

Naturally Acquired Immune Responses to Plasmodium falciparum Sexual Stage Antigens Pfs48/45 and Pfs230 in an Area of Seasonal Transmission

Naturally Acquired Immune Responses to Plasmodium falciparum Sexual Stage Antigens Pfs48/45 and Pfs230 in an Area of Seasonal Transmission

Epidemiology and Infectivity of Plasmodium falciparum and Plasmodium vivax Gametocytes in Relation to Malaria Control and Elimination

Biology of Malaria Transmission

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