scholarly journals Low Malaria Transmission in Rosso, an Irrigated Rice-Growing Area in Mauritania

Parasitologia ◽  
2021 ◽  
Vol 1 (4) ◽  
pp. 257-268
Author(s):  
Mohamed Aly Ould Lemrabott ◽  
Khadijetou Mint Lekweiry ◽  
Jemila Deida ◽  
Oum Kelthoum Mamadou Djigo ◽  
Mohamed Salem Ould Ahmedou Salem ◽  
...  
Keyword(s):  
Malaria Transmission ◽  
Mosquito Species ◽  
Epidemiological Data ◽  
Bed Nets ◽  
Entomological Surveillance ◽  
High Coverage ◽  
Travel History ◽  
Breeding Sites ◽  
Senegal River ◽  
Behavioural Aspects

The construction of dams along the Senegal River resulted in an increase in irrigated land areas and changes in the epidemiology and transmission of water-related diseases. The objective of this study was to update epidemiological data on malaria in Rosso, one of the major Mauritanian cities along the Senegal River. Febrile patients (n = 318) were screened for malaria using a rapid diagnostic test (RDT) for malaria and microscopic examination of blood smears. Diagnosis was later confirmed by polymerase chain reaction (PCR). The mean age of 318 febrile patients was 25.1 (range 1–80 years). Only 7 (2.2%) and 2 (0.6%) had a positive RDT and thick smear, respectively. PCR confirmed the diagnosis in two Plasmodium vivax-infected patients. Most participants (198/318, 62.3%) had no recent travel history outside Rosso. The majority of the febrile patients (90%, 284/311) owned at least one insecticide-treated net (ITN). The frequency of the use of ITNs was not significantly associated with season (rainy vs. dry seasons; p = 0.9) or with the number of ITNs per household (rs = 0.07; n = 285; p = 0.19). Of 285 individuals with ITNs, only two (0.7%) with no travel history were PCR-positive for malaria. Despite the presence of mosquito breeding sites related to rice irrigation, malaria transmission in Rosso remained very low, possibly due to the high coverage and frequent use of bed nets. Regular entomological surveillance for possible changes in the prevalence of Anopheles mosquito species and their behavioural aspects should be implemented.

scholarly journals A community-level investigation of the yellow fever virus outbreak in South Omo Zone, South-West Ethiopia, 2012–2014

2018 ◽  
Author(s):  
Ranya Mulchandani ◽  
Fekadu Massebo ◽  
Fekadu Bocho ◽  
Claire L Jeffries ◽  
Thomas Walker ◽  
...  
Keyword(s):  
Yellow Fever ◽  
Yellow Fever Virus ◽  
Mosquito Species ◽  
Breeding Site ◽  
Fever Virus ◽  
Entomological Surveillance ◽  
Breeding Sites ◽  
South Omo ◽  
South West Ethiopia ◽  
Aedes Simpsoni

AbstractBackgroundA yellow fever (YF) outbreak occurred in South Omo Zone, Ethiopia in 2012-2014. This study aimed to analyse historical epidemiological data, to assess the risk for future YF outbreaks through entomological surveillance, including mosquito species identification and molecular screening for arboviruses, and finally to determine the knowledge, attitudes and current preventative practices within the affected communities.Methodology/Principal FindingsFrom October 2012 to March 2014, 165 cases and 62 deaths were reported, principally in rural areas of South Ari region (83.6%), south-west Ethiopia. The majority of patients were 15-44 years old (74.5%) and most case deaths were males (76%). Between June and August 2017, 688 containers were sampled from across 177 households to identify key breeding sites forAedesmosquitoes.Ensete ventricosum(“false banana”) was identified as the primary natural breeding site, and clay pots outside the home as the most productive artificial breeding site. Entomological risk indices from the majority of sites were classified as “high risk” for future outbreaks under current World Health Organization criteria. Adult trapping resulted in the identification of members of theAedes simpsonicomplex in and around households. Screening of adult females revealed no detection of yellow fever virus (YFV) or other arboviruses. 88% of 177 participants had heard of YF, however many participants easily confused transmission and symptoms of YF with malaria, which is also endemic in the area.Conclusions/SignificanceStudy results emphasise the need for further entomological studies to improve our understanding of local vector species and transmission dynamics. Disease surveillance systems and in-country laboratory capacity also need to be strengthened to facilitate more rapid responses to future YF outbreaks.Author SummaryDespite the availability of a highly effective vaccine, yellow fever virus (YFV) remains an important public health problem across Africa and South America due to its high case-fatality rate. This study aimed to assess and reduce the risk for future outbreaks. During this study, historical data analysis was conducted to understand the epidemiology of the recent outbreak in 2012-2014. Entomological surveillance was also carried out, including both mosquito species identification and molecular screening for arboviruses, as well as a household survey to understand the knowledge and attitudes towards yellow fever (YF) within the affected areas and to assess community-level practices for YF prevention. We found a high abundance ofAedes simpsonicomplex in the context of low vaccination coverage. Community knowledge and practice levels were low for reducing potential breeding sites, highlighting the need for increased dissemination of information to community members on how to reduce their risk of exposure to mosquito vectors of arboviruses.

scholarly journals Emerging properties of malaria transmission and persistence in urban Accra, Ghana: Evidence from a participatory system approach

2021 ◽  
Author(s):  
Merveille Koissi Koissi Savi ◽  
Daniel Callo-Concha ◽  
Henri E.Z. Tonnang ◽  
Christian Borgemeister
Keyword(s):  
Network Analysis ◽  
Malaria Transmission ◽  
System Analysis ◽  
Public Awareness ◽  
Drug Prescription ◽  
Bed Nets ◽  
Emergent Properties ◽  
Breeding Sites ◽  
Leverage Points ◽  
Insecticide Treated Bed Nets

Abstract Several studies that aim to enhance the understanding of malaria transmission and persistence in urban settings failed to address its underlining complexity. We aim at doing that by applying a qualitative and participatory-based system analysis and mapping to elicit the system’s emergent properties. In two experts’ workshops, we sketched and refined the system, which was represented through a causal loop diagram, where the identification of leverage points was done using network analysis. We found 45 determinants interplaying through 56 linkages, and identified three subsystems: urbanization-related transmission, infection-prone behavior and healthcare efficiency, and Plasmodium resistance. Apart from the number of breeding sites and malaria positive cases, other determinants such as drug prescription and the awareness of householders were identified by the network analysis as leverage points and emergent properties of the system of transmission and persistence of malaria. Based on our findings, we suggest that ongoing efforts to control malaria, such as the use of insecticide-treated bed nets and larvicide applications should continue, and include new ones focusing on the public awareness and malaria literacy of city dwellers. We found that our participatory approach strengthened the legitimacy of the recommendations and the co-learning of participants.

scholarly journals Assessing the Intrinsic and Extrinsic Drivers and Targeting the Observed Resilience of Malaria in Northwestern and Southern Tanzania: A Protocol for a Cross-Sectional Exploratory Study

2020 ◽  
Author(s):  
Mercy G Chiduo ◽  
Celine I. Mandara ◽  
Susan F. Rumisha ◽  
Frank Chaky ◽  
Filbert T. Francis ◽  
...  
Keyword(s):  
Malaria Transmission ◽  
Control Strategies ◽  
Group Discussion ◽  
Bed Nets ◽  
Malaria Surveillance ◽  
Previous Night ◽  
High Coverage ◽  
Cross Sectional ◽  
Malaria Burden ◽  
Using Data

Abstract Background Despite high coverage and successes in malaria control strategies, some areas of Tanzania have indicated stagnantion or revesal of malaria burden. In malaria research, most studies are designed to assess drivers of malaria transmission focusing only on one dimension, single location while very few studies assess multiple components and their interactions. This article describes the protocol used to assess intrinsic and extrinsic drivers of persistent malaria transmission (hotsposts) in four regions from northwestern (Geita and Kigoma) and southern (Ruvuma and Mtwara) Tanzania.Results: Preliminary results show that 6,297 HHs and 28,361 individuals with median age of 16yrs (IQR= 7-35yrs) were registered from the 16 villages. Over 49% of individuals used bed-nets in the previous night before the survey and 43.9% of HHs had bed-nets covering two members per household. For parasitological survey, 25.8% of registered individuals (n=7,313) were selected from 2,527 HHs (40.1%) and invited for assessment and sampling. The positivity rate (PR) by mRDTs was 33.3% (range = 21.9% to 41.1%); while by microscopy, the PR was 20.6% and varied from 8.0% to 29.0%. Socio-anthropology interviews were conducted with a total of 1,687 heads/representatives of HHs. For qualitative surveys 32 Focus group discussion (two from each village) and 16 key informant interviews (two per district) were conducted. Thirty-one health facilities were visited for health system survey; 19.4% (n=6) were hospitals; 41.9% (n=13) health centres and 38.7% (n=12) dispensaries. For entomological survey, 8,891 adult mosquitoes were collected, whereby Anopheles gambiae complex, An. funestus group and other mosquitoes accounted for 12.0%, 49.7% and 38.3%, respectively.Conclusion: An analysis plan using data from the five components surveyed has been proposed and results from this study are expected to determine factors potentially responsible for persistence of malaria (hotspots) in the study areas. Rather than the traditional methodology of focusing on one metric, the approach will triangulate observations from all five components, highlighting understanding of potential drivers while studying their complex interactions and map spatial heterogeneity. This study will provide an important framework and data which will guide future studies and malaria surveillance in Tanzania and other malaria endemic countries.

scholarly journals Impact of promoting longer-lasting insecticide treatment of bed nets upon malaria transmission in a rural Tanzanian setting with pre-existing high coverage of untreated nets

2010 ◽  
Vol 9 (1) ◽  
Author(s):  
Tanya L Russell ◽  
Dickson W Lwetoijera ◽  
Deodatus Maliti ◽  
Beatrice Chipwaza ◽  
Japhet Kihonda ◽  
...  
Keyword(s):  
Malaria Transmission ◽  
Bed Nets ◽  
High Coverage ◽  
Insecticide Treatment

scholarly journals Emerging properties of malaria transmission and persistence in urban Accra, Ghana: evidence from a participatory system approach

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Merveille Koissi Savi ◽  
Daniel Callo-Concha ◽  
Henri E. Z. Tonnang ◽  
Christian Borgemeister
Keyword(s):  
Network Analysis ◽  
Malaria Transmission ◽  
System Analysis ◽  
Public Awareness ◽  
Drug Prescription ◽  
Bed Nets ◽  
Emergent Properties ◽  
Breeding Sites ◽  
Leverage Points ◽  
Insecticide Treated Bed Nets

Abstract Background Several studies that aim to enhance the understanding of malaria transmission and persistence in urban settings failed to address its underlining complexity. This study aims at doing that by applying qualitative and participatory-based system analysis and mapping to elicit the system’s emergent properties. Methods In two experts’ workshops, the system was sketched and refined. This system was represented through a causal loop diagram, where the identification of leverage points was done using network analysis. Results 45 determinants interplaying through 56 linkages, and three subsystems: urbanization-related transmission, infection-prone behaviour and healthcare efficiency, and Plasmodium resistance were identified. Apart from the number of breeding sites and malaria-positive cases, other determinants such as drug prescription and the awareness of householders were identified by the network analysis as leverage points and emergent properties of the system of transmission and persistence of malaria. Conclusion Based on the findings, the ongoing efforts to control malaria, such as the use of insecticide-treated bed nets and larvicide applications should continue, and new ones focusing on the public awareness and malaria literacy of city dwellers should be included. The participatory approach strengthened the legitimacy of the recommendations and the co-learning of participants.

scholarly journals Comparing sterile male releases and other methods for integrated control of the tiger mosquito in temperate and tropical climates

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Léa Douchet ◽  
Marion Haramboure ◽  
Thierry Baldet ◽  
Gregory L’Ambert ◽  
David Damiens ◽  
...  
Keyword(s):  
Vector Control ◽  
Mosquito Species ◽  
Integrated Control ◽  
Mass Trapping ◽  
Southwest Indian Ocean ◽  
Breeding Sites ◽  
Key Factor ◽  
Trapping Methods ◽  
Combination Of Methods ◽  
Tropical Climates

AbstractThe expansion of mosquito species worldwide is creating a powerful network for the spread of arboviruses. In addition to the destruction of breeding sites (prevention) and mass trapping, methods based on the sterile insect technique (SIT), the autodissemination of pyriproxyfen (ADT), and a fusion of elements from both of these known as boosted SIT (BSIT), are being developed to meet the urgent need for effective vector control. However, the comparative potential of these methods has yet to be explored in different environments. This is needed to propose and integrate informed guidelines into sustainable mosquito management plans. We extended a weather-dependent model of Aedes albopictus population dynamics to assess the effectiveness of these different vector control methods, alone or in combination, in a tropical (Reunion island, southwest Indian Ocean) and a temperate (Montpellier area, southern France) climate. Our results confirm the potential efficiency of SIT in temperate climates when performed early in the year (mid-March for northern hemisphere). In such a climate, the timing of the vector control action was the key factor in its success. In tropical climates, the potential of the combination of methods becomes more relevant. BSIT and the combination of ADT with SIT were twice as effective compared to the use of SIT alone.

scholarly journals Anopheles ecology, genetics and malaria transmission in northern Cambodia

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Amélie Vantaux ◽  
Michelle M. Riehle ◽  
Eakpor Piv ◽  
Elise J. Farley ◽  
Sophy Chy ◽  
...  
Keyword(s):  
Malaria Transmission ◽  
Mosquito Species ◽  
Rubber Tree ◽  
Amplicon Sequencing ◽  
Forest Sites ◽  
Baited Traps ◽  
Residual Malaria Transmission ◽  
Mosquito Ecology ◽  
Forested Areas ◽  
Greater Mekong Subregion

AbstractIn the Greater Mekong Subregion, malaria cases have significantly decreased but little is known about the vectors or mechanisms responsible for residual malaria transmission. We analysed a total of 3920 Anopheles mosquitoes collected during the rainy and dry seasons from four ecological settings in Cambodia (villages, forested areas near villages, rubber tree plantations and forest sites). Using odor-baited traps, 81% of the total samples across all sites were collected in cow baited traps, although 67% of the samples attracted by human baited traps were collected in forest sites. Overall, 20% of collected Anopheles were active during the day, with increased day biting during the dry season. 3131 samples were identified morphologically as 14 different species, and a subset was also identified by DNA amplicon sequencing allowing determination of 29 Anopheles species. The investigation of well characterized insecticide mutations (ace-1, kdr, and rdl genes) indicated that individuals carried mutations associated with response to all the different classes of insecticides. There also appeared to be a non-random association between mosquito species and insecticide resistance with Anopheles peditaeniatus exhibiting nearly fixed mutations. Molecular screening for Plasmodium sp. presence indicated that 3.6% of collected Anopheles were positive, most for P. vivax followed by P. falciparum. These results highlight some of the key mechanisms driving residual human malaria transmission in Cambodia, and illustrate the importance of diverse collection methods, sites and seasons to avoid bias and better characterize Anopheles mosquito ecology in Southeast Asia.

scholarly journals Low and seasonal malaria transmission in the middle Senegal River basin: identification and characteristics of Anopheles vectors

2012 ◽  
Vol 5 (1) ◽  
Author(s):  
Mamadou O Ndiath ◽  
Jean-Biram Sarr ◽  
Lobna Gaayeb ◽  
Catherine Mazenot ◽  
Seynabou Sougoufara ◽  
...  
Keyword(s):  
Malaria Transmission ◽  
River Basin ◽  
Senegal River ◽  
Anopheles Vectors ◽  
Senegal River Basin

scholarly journals Entomological Surveillance in Former Malaria-endemic Areas of Southern Italy

Pathogens ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1521
Author(s):  
Donato Antonio Raele ◽  
Francesco Severini ◽  
Daniela Boccolini ◽  
Michela Menegon ◽  
Luciano Toma ◽  
...  
Keyword(s):  
Malaria Vectors ◽  
Public Health Issue ◽  
Entomological Surveillance ◽  
Widespread Species ◽  
Animal Shelters ◽  
Breeding Sites ◽  
Artificial Breeding ◽  
Anopheles Vectors ◽  
Gargano Promontory ◽  
Anopheles Algeriensis

Malaria still represents a potential public health issue in Italy, and the presence of former Anopheles vectors and cases imported annually merit continuous surveillance. In areas no longer endemic, the concurrent presence of gametocyte carriers and competent vectors makes re-emergence of local transmission possible, as recently reported in Greece. In October 2017, due to the occurrence of four suspected introduced malaria cases in the province of Taranto (Apulia region), entomological investigations were performed to verify the involvement of local anopheline species. In 2019–2020 entomological surveys were extended to other areas historically prone to malaria between the provinces of Taranto and Matera and the province of Foggia (Gargano Promontory). Resting mosquitoes were collected in animal shelters and human dwellings, larvae were sampled in natural and artificial breeding sites, and specimens were both morphologically and molecularly identified. A total of 2228 mosquitoes were collected, 54.3% of which were anophelines. In all the investigated areas, Anopheles labranchiae was the most widespread species, while Anopheles algeriensis was predominant at the Gargano sites, and Anopheles superpictus and Anopheles plumbeus were recorded in the province of Matera. Our findings showed a potentially high receptivity in the surveyed areas, where the abundance of the two former malaria vectors, An. labranchiae and An. superpictus, is related to environmental and climatic parameters and to anthropic activities.

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