-
Medecine Tropicale Et Sante... Sep 2023Malaria is a major health problem in Benin where it is the main cause of morbidity and mortality, particularly among children under 5 and pregnant women. Although the...
BACKGROUND & RATIONALE
Malaria is a major health problem in Benin where it is the main cause of morbidity and mortality, particularly among children under 5 and pregnant women. Although the vast majority of malaria cases occurs in rural and agricultural areas and are often associated with development projects, very few interventions target the agro-ecosystem. In Benin, irrigated rice growing is expanding to meet the increasing demand of the population. However, continuous flooding and tillage systems induce the development and proliferation of malaria and other diseases vectors. Intermittent flooding of rice plots and minimal tillage can reduce significantly the proliferation of mosquitoes including in rice fields. However, the dissemination and implementation of these agricultural practices require community-wide action for greater effectiveness. As part of strengthening the capacity of farming communities in the fight against malaria vectors, the "Farmer Field School" appears to be an innovative approach. This learning by doing method promotes interactions between groups of producers to disseminate proven technologies. This study aims to disseminate among rice producers the agricultural practices of intermittent flooding and minimal tillage, likely to reduce the proliferation of malaria vectors in the rice fields.
MATERIALS & METHODS
This study was carried out in the rice-growing perimeter of Malanville, Benin (11° 52' 5" North, 3° 22' 59" East) which covers an area of 516 hectares. Farmer Field Schools were set up after a basic survey at producer level. This survey was carried out through in-depth interview, focus group discussions and direct field observation with producers. Focus groups discussions and interviews made it possible to understand the perception of rice farmers on the link between rice production and the transmission of malaria. In order to disseminate new agricultural practices such as intermittent flooding and minimal tillage among producers, twelve plots have been set up. Farmer Field Schools were monitored weekly with rice producers accompanied by a facilitator and a medical entomologist (learning facilitator or moderator) helping the farmers with the collection and identification of mosquito larvae. According to the different stages of rice development (transplanting, tillering, maturation), the mosquito larvae were collected in the test and control plots from 10 a.m. to 2 p.m. by the dipping method. Then the water in the test compartments (intermittent flooding) was emptied. A cycle of 7 days of flooding and 2 days of drying was carried out for intermittent flooding. Mosquito larvae were identified morphologically using the identification key and genus larvae were isolated in plastic cups. The impacts of intermittent flooding and minimum tillage in reducing breeding sites and larval densities were established by determining and comparing the larval densities of mosquitoes and of between the test and control plots.
RESULTS
Direct observations in the field allowed to identify three tillage systems, which include the use of tiller (28%), plow (66%) and hoe (6%) on the rice field. Continuous flooding was the only irrigation system used by farmers. The water used for irrigation comes either from boreholes installed individually or from the Niger River. The volume of water used varies with the seasons, the size of the farms and the variety of rice grown. Farmers observe that the nuisance of mosquitoes increases during the rice production period with an outbreak of malaria cases, especially among children, which leads to crowds in health centers. The preventive measures against malaria among farmers are the use of impregnated mosquito nets distributed free of charge by the national program against malaria, and of insecticide bombs or spirals. Considering the development stages of the rice, the larval densities varied according to the treatments. Overall, minimal tillage applied to intermittent flooding significantly reduced the density of mosquito larvae of all species. The reduction rates were 10.5, 5.4 and 2.5 during transplanting, tillering and maturation, respectively. Considering only the larvae, minimal tillage applied to intermittent flooding reduced their density by 16, 5.5 and 4 respectively during transplanting, tillering and maturation.
DISCUSSION/CONCLUSION
The rice-growing area of Malanville has many favorable conditions for rice production, including the presence of water supply sources such as the Niger River located near the rice field and numerous boreholes. The availability of water pockets for mosquito breeding during irrigation appeared to contribute to the extension of malaria transmission. The present study showed that the intermittent flooding coupled with minimal tillage could reduce the proliferation of malaria vectors. The results suggested that with technical support to farmers through the "Farmer Field School", the malaria incidence could be reduced in the farming community.
Topics: Pregnancy; Animals; Child; Humans; Female; Malaria; Ecosystem; Anopheles; Oryza; Farmers; Benin; Mosquito Vectors; Larva; Schools; Water
PubMed: 38094479
DOI: 10.48327/mtsi.v3i3.2023.281 -
MSphere Apr 2024Mosquito-borne viruses cause various infectious diseases in humans and animals. Tibet orbivirus (TIBOV), a newly identified arbovirus, efficiently replicates in...
Mosquito-borne viruses cause various infectious diseases in humans and animals. Tibet orbivirus (TIBOV), a newly identified arbovirus, efficiently replicates in different types of vertebrate and mosquito cells, with its neutralizing antibodies detected in cattle and goats. However, despite being isolated from midges and mosquitoes, there has been a notable absence of systematic studies on its vector competence. Thus, in this study, and were reared in the laboratory to measure vector susceptibility through blood-feeding infection. Furthermore, RNA sequencing was used to examine the overall alterations in the transcriptome following TIBOV infection. The results revealed that exhibited a high susceptibility to TIBOV compared to . Effective replication of the virus in midguts occurred when the blood-feeding titer of TIBOV exceeded 10 plaque-forming units mL. Nevertheless, only a few TIBOV RNA-positive samples were detected in the saliva of and , suggesting that these mosquito species may not be the primary vectors for TIBOV. Moreover, at 2 dpi of TIBOV, numerous antimicrobial peptides downstream of the Toll and Imd signaling pathways were significantly downregulated in , indicating that TIBOV suppressed mosquitos' defense to survive in the vector at an early stage. Subsequently, the stress-activated protein kinase JNK, a crucial component of the MAPK signaling pathway, exhibited significant upregulation. Certain genes were also enriched in the MAPK signaling pathway in TIBOV-infected at 7 dpi.IMPORTANCETibet orbivirus (TIBOV) is an understudied arbovirus of the genus . Our study is the first-ever attempt to assess the vector susceptibility of this virus in two important mosquito vectors, and . Additionally, we present transcriptome data detailing the interaction between TIBOV and the immune system of , which expands the knowledge about orbivirus infection and its interaction with mosquitoes.
Topics: Animals; Aedes; Culex; Mosquito Vectors; Orbivirus; Female; Virus Replication; Saliva; Transcriptome; Tibet
PubMed: 38530016
DOI: 10.1128/msphere.00062-24