Molecular evidence of high rates of asymptomatic P. vivax infection and very low P. falciparum malaria in Botswana

Motshoge, Thato; Ababio, Grace; Aleksenko, Larysa; Read, John S.; Peloewetse, Elias; Mazhani, Loeto; Mosweunyane, Tjantilili; Moakofhi, Kentse; Ntebele, Davies S.; Chihanga, Simon; Motlaleng, Mpho; Chinorumba, Anderson; Vurayai, Moses; Pernica, Jeffrey M.; Paganotti, Giacomo Maria; Quaye, Isaac

doi:10.1186/s12879-016-1857-8

Cited by 38 publications

(60 citation statements)

References 34 publications

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“…The decline in the incidence of Plasmodium falciparum infection has generated enthusiasm for the elimination of malaria. However, there is growing evidence of P. vivax infection in Duffy blood group negative populations (14)(15)(16)(17), and the species shift (18). may jeopardize malaria control efforts.…”

Section: Discussionmentioning

confidence: 99%

A decline and age shift in malaria incidence in rural Mali following implementation of seasonal malaria chemoprevention and indoor residual spraying

Coulibaly

Guindo

Niangaly

et al. 2020

Preprint

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BackgroundDeclines in malaria incidence attributed to the implementation of control strategies have been reported in many African countries. The declines are often accompanied by a shift in clinical burden to older children. In Mali, artemisinin-based combination therapy (ACT) was introduced in 2004, and Long-lasting insecticide-treated nets (LLINs) have been partially distributed free of charge since 2007. In Bandiagara, a study conducted from 2009 to 2013 showed a stable incidence of malaria compared to 1999 despite the use of ACTs and LLINs. Since 2016, seasonal malaria chemoprevention (SMC) has been scaled up across the country. In addition to these strategies, the population of Bandiagara benefited the universal bed net coverage and indoor residual spray (IRS) implementation in 2017 and 2018.This study aimed to measure the incidence of malaria in the context of recent scaling-up of control strategies.MethodsA cohort of 300 children aged 6 months to 15 years was followed from October 2017 to December 2018 in Mali. Monthly cross-sectional surveys were done to measure the prevalence of malaria infection by microscopy and anaemia. The study outcomes included the monthly prevalence of malaria infection and the incidence of symptomatic malaria.ResultsThe incidence of symptomatic malaria was 0.5 episodes/person-year. The average prevalence of malaria parasitaemia was 6.7%. The incidence was higher in the oldest age group than the youngest one (0.6 episodes/person-year in children above 10 years vs 0.29 in 6 months to 5 years age group).ConclusionsThis study showed a reduction of malaria incidence compared to 1999 and 2009-2013. An age shift in the susceptibility to malaria was also observed; older children experienced more clinical malaria than younger ones. These findings suggest to extend malaria control efforts to older children.

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Section: Discussionmentioning

confidence: 99%

A decline and age shift in malaria incidence in rural Mali following implementation of seasonal malaria chemoprevention and indoor residual spraying

Coulibaly

Guindo

Niangaly

et al. 2020

Preprint

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“…[7][8][9] Transmission of P. vivax in these high Duffy-negative regions has been attributed to P. vivax strains circulating among Duffy-positive residents and travelers, or possibly an ape reservoir. [10][11][12] However, recent studies have demonstrated P. vivax infections in Duffy-negative individuals across Africa, including Angola and Equatorial Guinea, 13 Benin, 14 Botswana, 15 Cameroon, 16,17 Ethiopia, 18,19 Western Kenya, 20 Madagascar, 6 Mauritania, 21 and central Sudan 22 (reviewed recently by Zimmerman et al). 23 In addition, standard blood smear microscopy has demonstrated ring-stage formation in infected reticulocytes from Duffy-negative patients, confirming that the P. vivax detected in some cases was invasive and not merely transient merozoites in the blood.…”

Section: Introductionmentioning

confidence: 99%

Plasmodium vivax Infections in Duffy-Negative Individuals in the Democratic Republic of the Congo

Brazeau

Whitesell

Doctor

et al. 2018

The American Journal of Tropical Medicine and Hygiene

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Although has been assumed to be absent from sub-Saharan Africa because of the protective mutation conferring the Duffy-negative phenotype, recent evidence has suggested that cases are prevalent in these regions. We selected 292 dried blood spots from children who participated in the 2013-2014 Demographic and Health Survey of the Democratic Republic of the Congo (DRC), to assess for infection. Four infections were identified by polymerase chain reaction, each in a geographically different survey cluster. Using these as index cases, we tested the remaining 73 samples from the four clusters. With this approach, 10 confirmed cases, three probable cases, and one possible case of were identified. Among the 14 cases, nine were coinfected with . All 14 individuals were confirmed to be Duffy-negative by sequencing for the single point mutation in the GATA motif that represses the expression of the Duffy antigen. This finding is consistent with a growing body of literature that suggests that can infect Duffy-negative individuals in Africa. Future molecular and sequencing work is needed to understand the relationship of these isolates with other samples from Asia and South America and discover variants linked to virulence and erythrocyte invasion.

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“…vivax is becoming a serious health problem exhibiting a wide range of hosts children [6], adults [55] and even pregnant women [56]. Also has been detected on asymptomatic individuals [57,58]. The underestimation of P. vivax malaria infections could be attributed to misdiagnosis of the disease using Rapid diagnostic tests RTDs [59], presence of hypnozoite on reservoirs which again cannot be detected using RTDs [60].…”

Section: Previous Studies Onmentioning

confidence: 99%

Molecular and morphological identification of suspected Plasmodium vivax vectors in Central and Eastern Sudan

Abdelwhab

Elaagip

Albsheer

et al. 2020

Preprint

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Background: In spite of the global effort to eliminate malaria, it remains the most significant vector-borne disease of humans. Plasmodium falciparum remains the dominant malaria parasite in Sub-Saharan Africa. However, P. vivax is becoming widely spread throughout Africa. The overuse of vector control methods has resulted in a remarkable change in the behaviour of mosquito that feeds on human as well as on vector composition. The aim of this study was to identify Anopheles mosquito species in vivax malaria endemic regions and to investigate their role in P. vivax malaria transmission.Methods: Mosquito samples were collected from Central Sudan (Khartoum and Sennar States) and Eastern Sudan (New Halfa) using Pyrethrum Spray Catch (PSC) and CDC light traps. Mosquitoes were identified using appropriate morphological identification keys and Anopheles gambiae complex were confirmed to species level using molecular analysis. A subset of blood-fed anopheline mosquitoes were dissectedto study the presence of natural infection of malaria parasites. In addition, the rest of the blood-fed samples were investigated for presence of infective sporozoites of P. vivax that detecting the P. vivax circumsporozoite protein (pvcsp) gene using nested-PCR.Results: A total of 644 adult anopheline blood-fed mosquitoes were collected from New Halfa (N = 214 mosquitoes), Khartoum (N = 132 mosquitoes), and Sennar (N = 298 mosquitoes). Morphological and molecular identification of the collected mosquitoes revealed the presence of An. arabiensis, An. funestus, and An. pharoensis. Out of 644 anophelines subjected to P. vivax sporozoite detection (N = 40, 6.2%) were positive for P. vivax.An. arabiensis 6.7% (39/583) and An. pharoensis 1.8% (1/56) were found positive for the parasite. While An. funestus was detected for the first time in New Halfa with low abundance (5/214 mosquitoes) and were found negative for the parasite.Conclusion: This study documented the presence of An. funestus for the first time in New Halfa, Eastern Sudan. However, An. arabiensis is the most abundant vector detected, together with An. pharoensis. This findings suggests change in malaria epidemiology. Further studies are needed to investigate their contribution in malaria transmission.

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Molecular evidence of high rates of asymptomatic P. vivax infection and very low P. falciparum malaria in Botswana

Cited by 38 publications

References 34 publications

A decline and age shift in malaria incidence in rural Mali following implementation of seasonal malaria chemoprevention and indoor residual spraying

A decline and age shift in malaria incidence in rural Mali following implementation of seasonal malaria chemoprevention and indoor residual spraying

Plasmodium vivax Infections in Duffy-Negative Individuals in the Democratic Republic of the Congo

Molecular and morphological identification of suspected Plasmodium vivax vectors in Central and Eastern Sudan

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