Breeding Site Characteristics of Mosquito in Ouagadougou, Burkina Faso

Urban areas deal with the emergence or resurgence of transmissible and non-transmissible diseases, linked in particular to urban lifestyle and sanitation issues. Human practices create or maintain conditions that favour mosquitoes’ breeding. This study investigates mosquito breeding sites characteristics in Ouagadougou, from September to November 2020. Mosquito larvae were sampled across three districts in the city, chosen based on socio-demographic and urbanization levels. The larval collection from natural breeding sites using the ladle technique and larvae transferred to can. For artificial sites, the larvae were transferred directly into can Larvae were collected from 83 breeding sites, predominantly artificial: 39% in plastic containers, 23% in clay containers, and 13% in metal, while natural sites like puddles accounted for only 25%. A total of 8352 mosquitoes were identified as six species: Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, Anopheles gambiae s.l., Anopheles funestus, and Mansonia africana. Ae. aegypti was the most prevalent, found across all breeding site types, whereas Culex quinquefasciatus and Anopheles gambiae were mainly in natural sites. Physico-chemical analysis of the breeding sites revealed that conductivity and turbidity were consistent across breeding sites. The highest median pH values were observed in ceramic and metal containers. Water temperature showed minimal variation. The presence of Anopheles gambiae and Culex quinquefasciatus correlated with higher water temperature, turbidity, and conductivity. Anopheles funestus preferred high pH environments. Conversely, Aedes aegypti, Aedes albopictus, and Mansonia africana were less influenced by these parameters. The findings underscore the need for community involvement in water and waste management to control mosquito populations, especially targeting the Aedes aegypti species. Raising awareness among locals about proper water storage and disposal practices is crucial for effective vector control.

Evaluation of the physicochemical indices of blackflies(Diptera:Simuliidae)breeding sites in Delta State,Nigeria:Implication for onchocerciasis control

Objective:To determine the ecological parameters affecting the distribution of Simulium damnosum immature stages in some rivers within the endemic areas of Delta State,Nigeria.Methods:Onchocerca larvae were observed and identified for each river.An average sized colander with fine mesh was used to scoop the area to obtain the larvae along with other benthos.Physiochemical characteristics of the water at breeding sites were analyzed for a 12 months period.Correlation analysis was performed to establish the association between the larval densities and physicochemical parameters of blackfly.Results:The seasonal variation in the physical and chemical characteristics of these environments impaired the population dynamics of blackflies.The physicochemical parameters significantly varied among breeding sites(P<0.05),in which the temperature of surface water ranged between 23.2°C and 30.3°C,water flow velocity ranged between 0.4 and 1.3 m/s,dissolved oxygen ranged between 5.1 and 9.0 mg/L and pH ranged between 5.4 and 7.4.The mean collection of Simulium larvae was the highest in River Otor(44.1)and the least in River Namormai(19.1).There was significant difference(P<0.05)in the number of larvae collected from the sampled rivers.Also,the number of larvae collected significantly correlated with surface water temperature,water flow velocity,dissolved oxygen and pH.Conclusions:This study identified significant correlations between physicochemical parameters and blackfly larvae densities thus providing a precontrol evidence-based data for the control of onchocerciasis in the endemic areas of North Delta.

Soundscape Dynamics at Anuran Reproductive Sites in Pannonian Biogeographical Region：Effects of Road Noise on Vocal Activity

The emerging field of soundscape ecology views ecosystems in terms of biophony, geophony and anthrophony. Soundscape ecology considers the effects of sound on fauna, and this research focuses on anuran breeding lek soundscapes. The sensitivity of anuran breeding leks to acoustic disturbances makes breeding leks an important venue for a comparative soundscape study. We made long-term（〉 24 h） sound recordings in three representative wetlands and short-term（〈 30 min） recordings in ten sites in the Pannonian Biogeographical Region of Hungary and around the Hungary and Slovakia border. Long-term soundscapes of the floodplain stretch, where there is relatively minor anthrophonical disturbance, showed an obvious circadian change in sound intensities. The site with moderate sound contamination exhibited a disturbed pattern of circadian sound variation, while the site with heavy traffic noise displayed an apparently random temporal soundscape. At different amphibian breeding sites during mating season, our short-term recordings were dominated by anuran calls, bird songs and wind noises, while insect calls and rain were present to a lesser degree. Our study indicates that vehicle traffic noise is a severe imposition to the natural soundscape, and suggests that soundscape monitoring can provide a reliable and sensitive index of environmental change for both short-term and long-term periods.

Mosquito larva distribution and natural Wolbachia infection in campus areas of Nakhon Ratchasima,Thailand

Objective:To determine the prevalence of mosquito larvae in campus areas and the infection rate of endosymbiotic bacteria,Wolbachia in mosquito larvae.Method:The mosquito larvae samples were collected in residential areas and academic buildings of Suranaree University of Technology located in Northeastern Thailand during 2017-2018.Mosquito species identification was performed using GLOBE mosquito protocols and Rattanarithikul&Panthusiri’s keys.The gene encoding for the surface protein of Wolbachia was amplified by PCR and confirmed by DNA sequencing.Results:Armigeres sp.is the highest proportion of mosquito larvae followed by Culex spp.,Aedes albopictus,Aedes aegypti,and Toxorynchites spp.,respectively.Aedes aegypti have breeding sites mostly in the containers found indoors,whereas the main breeding sites of Aedes albopictus were found in both outdoors and indoors.The House Index and Breteau Index for Aedes spp.was more than 5%and 20%,respectively,in both areas,indicating that these areas are dengue sensitive.The highest proportion of Wolbachia infection was found in the larvae of Culex spp.(86.21%),followed by Aedes albopictus(69.23%)and rarely detected in Aedes aegypti(9.09%).Conclusion:The present study reported the first natural infection of Wolbachia in mosquito larvae in Thailand.Our result suggested that the mosquito species containing higher proportion of Wolbachia are less likely to be vectors for dengue.Therefore,Wolbachia transfection in mosquito larvae could be applied as a biocontrol for dengue and other mosquito-borne disease prevention.

Urban schistosomiasis and associated determinant factors among school children in Bamako, Mali, West Africa

Background:Schistosomiasis is classically described as a rural disease that occurs in areas with poor sanitary conditions.However,over recent decades,there has been an expansion of schistosomiasis foci towards urban areas faced with a rapid and disordered urbanization.In Bamako,Mali,the impact of environmental change on vector-borne diseases such as schistosomiasis is not well known.This study sought to identify the presence of schistosomiasis transmission hotspots in Bamako.Using this perspective,we aimed to describe the risk factors of the endemization and maintenance of schistosomiasis.Materials and methods:A cross-sectional study was carried out in the six municipalities(communes)in Bamako.Environmental information was obtained from earth observation satellites in order to maximize ecological contrasts.Twenty-nine blocks of 200 m x 200 m were identified.We selected a school inside or nearest to each block for urine and stool samples examination.The study cohort was school children aged between eight and 15 years.The Kato-Katz technique and filtration were used for Schistosoma mansoni and S.haematobium ova research in stools and urine,respectively.The schools and snail breeding sites were georeferenced.Four malacological surveys were conducted between October 2011 and February 2012.Bivariate analysis was used to identify independent predictors of being infected with schistosomiasis.Results:The prevalence rate of S.haematobium was 14.7%(n=1,761)and that of S.mansoni 1.5%(n=1,491).Overall,the urinary form was endemic in 76.6%of schools.The infection significantly varied between the municipalities(p<0.001).It was also more prevalent on the left side of the Niger River than the right side(17.4%vs.9.5%respectively;p<0.001).The vicinity to snail breeding sites(OR=3.677;95%IC[2.765–4.889];p<10-3)and parents’occupations(OR=7.647;95%IC[2.406–24.305];p<0.001)were the most important risk factors associated with S.haematobium infection exposure.Biomphalaria pfeifferi,Bulinus truncatus,and B.globosus were the intermediate hosts captured.The schistosome natural infection rates(SNIRs),which were low or nil in October and November,rose to 2.8%in January and 8.3%in February for B.pfeifferi and B.truncatus,respectively.Conclusion:Our findings show that there is a high transmission risk for schistosomiasis in Bamako.Appropriate integrated control measures need to be introduced to control the transmission of this disease in the study area.