scholarly journals Differential contribution of Anopheles coustani and Anopheles arabiensis to the transmission of Plasmodium falciparum and Plasmodium vivax in two neighboring villages of Madagascar

2019 ◽  
Author(s):  
Jessy Goupeyou-Youmsi ◽  
Tsiriniaina Rakotondranaivo ◽  
Nicolas Puchot ◽  
Ingrid Peterson ◽  
Romain Girod ◽  
...  
Keyword(s):  
Plasmodium Vivax ◽  
Malaria Transmission ◽  
Malaria Vector ◽  
Anopheles Arabiensis ◽  
Malaria Prevalence ◽  
Health Concern ◽  
Transmission Season ◽  
Human Malaria ◽  
Malaria Transmission Season ◽  
Elimination Goal

AbstractBackgroundMalaria is still a heavy public health concern in Madagascar. Few studies combining parasitology and entomology have been recently conducted despite the need for such information to design proper vector control measures. In a region of moderate to intense transmission of both Plasmodium falciparum and Plasmodium vivax, we conducted a combined parasitology and entomology survey in two nearby villages, across a malaria transmission season from December 2016 to April 2017.Methodology/Principal findingsCommunity-based surveys were conducted in the two close by villages at three time points during a single malaria transmission season. Plasmodium carriage in the human populations was determined by Rapid Diagnostic Tests (RDTs), microscopy and real-time PCR. Anthropophilic mosquitoes were captured by human landing captures and presence of Plasmodium sporozoites was assessed by robust Real Time PCR. Overall human malaria prevalence was 8.0% by RDT, 4.8% by microscopy and 11.9% by PCR, mainly due to P. falciparum detected in 92.2% of the PCR positive samples and Plasmodium vivax (5.7%). No significant differences in Plasmodium human carriage was observed between the 2 villages at any time point. Of the 1553 anopheline mosquitoes tested, 13 were found carrying Plasmodium sporozoites, the majority of them being captured outdoor. The mosquito sporozoite indices were not significantly different between the two villages. However, our entomological analysis revealed that Anopheles coustani was the main vector in one village, being responsible of 25.5 infective bites during the whole survey, whereas it was Anopheles arabiensis in the other village with 15 infective bites. In addition, we found a significant higher number of endophagic An. coustani and An. arabiensis in one village compared to the other.Conclusions/SignificanceDespite similar human malaria prevalence in two close by villages, the entomological survey demonstrated the contribution of two different mosquito species in each village, and importantly the role of a suspected secondary malaria vector, An. coustani, as the main vector in one village. This, along with its higher endophagic rate in that village, highlights the importance of combining parasitology and entomology surveys for better targeting the actual local malaria vector. Such study should contribute to the malaria pre-elimination goal established under the 2018-2022 National Malaria Strategic Plan.Author SummaryMalaria is still a major health concern in many countries in sub-Saharan Africa such as Madagascar. In this study, we determined the contribution of malaria vectors in the transmission of Plasmodium parasites in two nearby villages in an area of moderate to high malaria transmission in Madagascar. We collected, during a single malaria transmission season, parasitological data in the human population and entomological data in the mosquito population, in order to evaluate Plasmodium carriage in these two populations. The results showed that despite similarity in human malaria prevalence and in vector species diversity in each village, the contribution of vectors was different between the two villages. An. arabiensis was the major vector in Ambohitromby while it was An. coustani that played this role in Miarinarivo. Importantly, this study is the first that clearly demonstrates that An. coustani could act as a major local vector in Madagascar. Such study should help deploying adapted malaria vector control and contributing to the malaria pre-elimination goal established under the 2018-2022 National Malaria Strategic Plan.

scholarly journals Long-distance transmission patterns modelled from SNP barcodes of Plasmodium falciparum infections in The Gambia

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Alfred Amambua-Ngwa ◽  
David Jeffries ◽  
Julia Mwesigwa ◽  
Aminata Seedy-Jawara ◽  
Joseph Okebe ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Malaria Transmission ◽  
Genetic Relatedness ◽  
Malaria Prevalence ◽  
The Gambia ◽  
Long Distance ◽  
Travel History ◽  
Transmission Season ◽  
Malaria Transmission Season ◽  
Likelihood Model

Abstract Malaria has declined significantly in The Gambia and determining transmission dynamics of Plasmodium falciparum can help targeting control interventions towards elimination. This can be inferred from genetic similarity between parasite isolates from different sites and timepoints. Here, we imposed a P. falciparum life cycle time on a genetic distance likelihood model to determine transmission paths from a 54 SNP barcode of 355 isolates. Samples were collected monthly during the 2013 malaria season from six pairs of villages spanning 300 km from western to eastern Gambia. There was spatial and temporal hierarchy in pairwise genetic relatedness, with the most similar barcodes from isolates within the same households and village. Constrained by travel data, the model detected 60 directional transmission events, with 27% paths linking persons from different regions. We identified 13 infected individuals (4.2% of those genotyped) responsible for 2 to 8 subsequent infections within their communities. These super-infectors were mostly from high transmission villages. When considering paths between isolates from the most distant regions (west vs east) and travel history, there were 3 transmission paths from eastern to western Gambia, all at the peak (October) of the malaria transmission season. No paths with known travel originated from the extreme west to east. Although more than half of all paths were within-village, parasite flow from east to west may contribute to maintain transmission in western Gambia, where malaria transmission is already low. Therefore, interrupting malaria transmission in western Gambia would require targeting eastern Gambia, where malaria prevalence is substantially higher, with intensified malaria interventions.

scholarly journals Control of Plasmodium vivax malaria by mass chemoprevention with primaquine

2018 ◽  
Vol 4 ◽  
Author(s):  
Hyon-Ok Kim ◽  
Tong-Chan Ko ◽  
Song-Su Kim ◽  
Song-Guk Im ◽  
Yun-Nam Kim
Keyword(s):  
Adverse Effects ◽  
Plasmodium Vivax ◽  
Malaria Transmission ◽  
Vivax Malaria ◽  
Protective Efficacy ◽  
Short Form ◽  
Transmission Season ◽  
Malaria Transmission Season ◽  
Long Form ◽  
Plasmodium Vivax Malaria

Abstract In Democratic People's Republic of Korea, only Plasmodium vivax malaria is prevalent, which is divided into two forms – long incubation form and short form. Among malaria cases reported in a year, long form accounts for 69% and short form 31%. Incubation period of short form ranges from 10 to 29 days (average 17 days) and long from 5·5 to 16 months (average 8–13 months). The most relapses (90%) were reported from May to September – malaria transmission season in the country. Result from preliminary mass chemoprevention in small size of population before transmission season to find appropriate method showed high protective efficacy in two regimens – one regimen given primaquine 0·25 mg base kg−1 day−1 for 14 days (95%) and another 0·5 mg base kg−1 day−1 for 7 days (94%). During the mass chemoprevention with primaquine, some adverse effects were reported but transient. We consider that mass chemoprevention with primaquine before transmission season is of great significance in disturbing the vivax malaria transmission, in which long incubation form is predominant in countries prevailing seasonal malaria.

scholarly journals Mapping Malaria Transmission Risk in Northern Morocco Using Entomological and Environmental Data

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
E. Adlaoui ◽  
C. Faraj ◽  
M. El Bouhmi ◽  
A. El Aboudi ◽  
S. Ouahabi ◽  
...  
Keyword(s):  
Plasmodium Vivax ◽  
Malaria Transmission ◽  
Satellite Imagery ◽  
Malaria Vector ◽  
Environmental Changes ◽  
Temporal Variations ◽  
Environmental Data ◽  
Transmission Risk ◽  
Cultivation Period ◽  
Very High

Malaria resurgence risk in Morocco depends, among other factors, on environmental changes as well as the introduction of parasite carriers. The aim of this paper is to analyze the receptivity of the Loukkos area, large wetlands in Northern Morocco, to quantify and to map malaria transmission risk in this region using biological and environmental data. This risk was assessed on entomological risk basis and was mapped using environmental markers derived from satellite imagery. Maps showing spatial and temporal variations of entomological risk for Plasmodium vivax and P. falciparum were produced. Results showed this risk to be highly seasonal and much higher in rice fields than in swamps. This risk is lower for Afrotropical P. falciparum strains because of the low infectivity of Anopheles labranchiae, principal malaria vector in Morocco. However, it is very high for P. vivax mainly during summer corresponding to the rice cultivation period. Although the entomological risk is high in Loukkos region, malaria resurgence risk remains very low, because of the low vulnerability of the area.

scholarly journals Estimation of malaria transmission in high-risk provinces of Morocco

2003 ◽  
Vol 9 (4) ◽  
pp. 542-547
Author(s):  
C. Faraj ◽  
E. Adlaoui ◽  
M. Rhajaoui ◽  
M. Lyagoubi
Keyword(s):  
High Risk ◽  
Plasmodium Vivax ◽  
Malaria Transmission ◽  
Immunosorbent Assay ◽  
Epidemiological Studies ◽  
Enzyme Linked Immunosorbent Assay ◽  
Light Traps ◽  
Human Malaria ◽  
Mosquito Collection ◽  
Transmission Level

The malaria transmission level of Plasmodium vivax was monitored in four high-risk provinces in Morocco. Intensive mosquito collection by light traps and manual catches resulted in the capture of four species: Anopheles labranchiae, An. sergenti, An. cinereus, and An. claviger. All An. sergenti and An. labranchiae females collected were tested for the presence of two phenotypes of P. vivax [PVK210 and PVK247] antigen by enzyme-linked immunosorbent assay [ELISA]. No P. vivax antigen was detected in 1347 mosquitoes analysed. A parallel parasitological investigation was conducted. Of 2665 slides examined from a population of 4343 people for detection of P. vivax, no slide was positive. The results confirm the break in malaria transmission in residual foci. The use of ELISA is recommended in future epidemiological studies of human malaria.

scholarly journals Effect of bendiocarb based (Ficam® 80% WP) Indoor Residual Spraying on feeding patterns from malaria vectors in Burkina Faso, West Africa.

2020 ◽  
Author(s):  
Sawdetuo Aristide HIEN ◽  
Dieudonné Diloma Soma ◽  
Simon Pengwende Sawadogo ◽  
Serge Bèwadéyir Poda ◽  
Moussa Namountougou ◽  
...  
Keyword(s):  
Burkina Faso ◽  
Anopheles Gambiae ◽  
Malaria Transmission ◽  
Malaria Vector ◽  
Indoor Residual Spraying ◽  
Transmission Risk ◽  
Malaria Vectors ◽  
Anopheles Coluzzii ◽  
Transmission Season ◽  
Density Methods

Abstract Background The fight against vector is essential in malaria prevention strategies in several endemic countries in Africa. In Burkina Faso, malaria transmission is seasonal in most parts of country, so a single round of spraying should provide effective protection against malaria, provided the insecticide remains effective over the entire malaria transmission season. The outcomes of indoor residual spraying towards curtailing malaria transmission are firstly to decrease the life span of vector mosquitoes and also to reduce the malaria vectors density. Methods CDC light trap and early morning collections by pyrethrum spray catches were performed monthly to determine the change in malaria vector indices in sprayed (Diebougou) and unsprayed sites (Dano). The female’s malaria vectors collected by both methods were used to determine their blood feeding, biting and sporozoites rate and malaria transmission risk estimated by entomological inoculation rate. Results Anopheles gambiae complex composed to Anopheles gambiae, Anopheles coluzzii and Anopheles arabiensis were present throughout the transmission season, but An. gambiae was the predominant species collected (P =0.0005), comprising 88% of the total collected and the most infected species. Malaria vectors densities were significantly lower in sprayed villages (n=4,303) compared with unsprayed villages (n=12,569) during post-spraying period (P = 0.0012). In addition, mean human biting rate of An. gambiae sl and An . funestus ss were significantly lower in sprayed areas compared to unsprayed areas (P<0.05). Overall, malaria vector transmission risk was significant lower in villages which received IRS (P=0.0001) whatever the malaria vectors species ( An. gambiae sl and An. funestus ss). Conclusions The results showed that in the sprayed area (Diebougou), vector densities, human biting rates and malaria transmission risks were very lower than unsprayed areas (Dano). The findings also showed a change in vector behavior especially within An. funestus which became more zoophagic following IRS. The indoor residual spraying could be recommanded as control tool in areas where malaria transmission occured a given period of year.

Reduced cellular immune reactivity in healthy individuals during the malaria transmission season

1990 ◽  
Vol 25 (1-3) ◽  
pp. 237-242 ◽  
Author(s):  
Thor G. Theander ◽  
Lars Hviid ◽  
Yousif A. Abu-Zeid ◽  
NasrEldin H. Abdulhadi ◽  
Bakri O. Saeed ◽  
...  
Keyword(s):  
Malaria Transmission ◽  
Immune Reactivity ◽  
Healthy Individuals ◽  
Transmission Season ◽  
Malaria Transmission Season ◽  
Cellular Immune

scholarly journals Effect of bendiocarb based (Ficam® 80% WP) Indoor Residual Spraying on feeding patterns from malaria vectors in Burkina Faso, West Africa.

2020 ◽  
Author(s):  
Sawdetuo Aristide HIEN ◽  
Dieudonné Diloma Soma ◽  
Simon Pengwende Sawadogo ◽  
Serge Bèwadéyir Poda ◽  
Moussa Namountougou ◽  
...  
Keyword(s):  
Burkina Faso ◽  
Malaria Transmission ◽  
Malaria Vector ◽  
Light Trap ◽  
Indoor Residual Spraying ◽  
Malaria Prevention ◽  
Transmission Risk ◽  
Malaria Vectors ◽  
Anopheles Coluzzii ◽  
Transmission Season

Abstract Background: The fight against vector is essential in malaria prevention strategies in several endemic countries in Africa. In Burkina Faso, malaria transmission is seasonal in most parts of country, so a single round of spraying should provide effective protection against malaria, provided the insecticide remains effective over the entire malaria transmission season. The outcomes of indoor residual spraying towards curtailing malaria transmission are firstly to decrease the life span of vector mosquitoes and also to reduce the malaria vectors density.Methods : CDC light trap and early morning collections by pyrethrum spray catches were performed monthly to determine the change in malaria vector indices in sprayed (Diebougou) and unsprayed sites (Dano). The female’s malaria vectors collected by both methods were used to determine their blood feeding, biting and sporozoites rate and malaria transmission risk estimated by entomological inoculation rate.Results: Anopheles gambiae complex composed to Anopheles gambiae, Anopheles coluzzii and Anopheles arabiensis were present throughout the transmission season, but An. gambiae was the predominant species collected (P =0.0005), comprising 88% of the total collected and the most infected species. Malaria vectors densities were significantly lower in sprayed villages (n=4,303) compared with unsprayed villages (n=12,569) during post-spraying period (P = 0.0012). In addition, mean human biting rate of An. gambiae sl and An. funestus sl were significantly lower in sprayed areas compared to unsprayed areas (P<0.05). Overall, malaria vector transmission risk was significant lower in villages which received IRS (P=0.0001) whatever the malaria vectors species (An. gambiae sl and An. An. funestus sl).Conclusions: The results showed that in the sprayed area (Diebougou), vector densities, human biting rates and malaria transmission risks were very lower than unsprayed areas (Dano). The findings also showed a change in vector behavior especially within An. funestus which became more zoophagic following IRS. The indoor residual spraying could be recommanded as control tool in areas where malaria transmission occured a given period of year.

scholarly journals Gametocyte clearance in children, from western Kenya, with uncomplicated Plasmodium falciparum malaria after artemether–lumefantrine or dihydroartemisinin–piperaquine treatment

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Protus Omondi ◽  
Marion Burugu ◽  
Damaris Matoke-Muhia ◽  
Edwin Too ◽  
Eva A. Nambati ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Malaria Transmission ◽  
Plasmodium Falciparum Malaria ◽  
Western Kenya ◽  
Transmission Season ◽  
Gametocyte Carriage ◽  
Qrt Pcr ◽  
Malaria Transmission Season ◽  
Significant Difference ◽  
Blocking Malaria Transmission

Abstract Background The efficacy and safety of artemether–lumefantrine (AL) and dihydroartemisinin–piperaquine (DP) against asexual parasites population has been documented. However, the effect of these anti-malarials on sexual parasites is still less clear. Gametocyte clearance following treatment is essential for malaria control and elimination efforts; therefore, the study sought to determine trends in gametocyte clearance after AL or DP treatment in children from a malaria-endemic site in Kenya. Methods Children aged between 0.5 and 12 years from Busia, western Kenya with uncomplicated Plasmodium falciparum malaria were assigned randomly to AL or DP treatment. A total of 334 children were enrolled, and dried blood spot samples were collected for up to 6 weeks after treatment during the peak malaria transmission season in 2016 and preserved. Plasmodium falciparum gametocytes were detected by qRT-PCR and gametocyte prevalence, density and mean duration of gametocyte carriage were determined. Results At baseline, all the 334 children had positive asexual parasites by microscopy, 12% (40/334) had detectable gametocyte by microscopy, and 83.7% (253/302) children had gametocytes by RT-qPCR. Gametocyte prevalence by RT-qPCR decreased from 85.1% (126/148) at day 0 to 7.04% (5/71) at day 42 in AL group and from 82.4% (127/154) at day 0 to 14.5% (11/74) at day 42 in DP group. The average duration of gametocyte carriage as estimated by qRT-PCR was slightly shorter in the AL group (4.5 days) than in the DP group (5.1 days) but not significantly different (p = 0.301). Conclusion The study identifies no significant difference between AL and DP in gametocyte clearance. Gametocytes persisted up to 42 days post treatment in minority of individuals in both treatment arms. A gametocytocidal drug, in combination with artemisinin-based combination therapy, will be useful in blocking malaria transmission more efficiently.

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