An artificial feeder for breeding and infection of mosquitoes

BONICA MELISA BERENICE; GOENAGA SILVINA; CHUCHUY, AILÉN; MARTI, GERARDO ANÍBAL; MUTTIS, EVANGELINA; MICIELI MARIA VICTORIA,

MANAUS, STATE OF AMAZONAS, BRAZIL

Congreso; 1st ANNUAL MEETING OF THE LATIN AMERICAN SOCIETY FOR VECTOR ECOLOGY; 2019

Society of Vector Ecology

Introduction:Aedes aegypti is the main urban vector of many flavivirus involved in human diseases, such as Dengue (DENV), Zika (ZIKV) and Yellow Fever (YFV). For this reason, it is subject of study all over the world where Ae. aegypti colonies are well established in insectaries. As a blood meal is required by female mosquitoes to produce eggs, this is a critical step while rearing a colony. In laboratory live animals are usually employed to maintain a colony, while several artificial feeders, which differ for some features were developed for experimental assays. In this study we propose a method of alimentation which gathers the best qualities in order to eliminate the use of laboratory animals, improve mass rearing, and obtain a safe and autoclavable feeder that can be employed for oral infections.Methodology: According to the available literature and taking into considerations the best characteristics of the artificial feeders previously described (material, type of membrane employed, method of temperature regulation) we developed a feeding device characterized by low cost, safety and sterility, together with a practical assembly and disassembly of the unit. The efficiency of this apparatus was measured by using three reproductive parameters (hatchability, blood feeding rate, and number of eggs laid by each colony) and by performing a vector competence assay.Ae.aegypti eggs from an established colony in La Plata (Argentina) were hatched (Parental line, P). Egg hatchability was recorded after 48hs. Larvae, pupae and adults mosquitoes were observed daily. Emerged adults were counted and sexed, and a blood meal was offered once a week. For this purpose a glass feeder which employs a cattle gut membrane, and blood maintained at 37°C due to a hot water circulation system around the device was employed. Engorged females were counted to determine the blood feeding rate. The eggs laid during each week were counted and subsequently hatched for the filial generation (F1) follow up.To evaluate vector competence, Ae.aegypti adults were fed with infected blood. Body, legs and saliva were harvested and tested by plaque tritation for ZIKV in order to calculate infection, transmission, and dissemination rates, respectively.Results: After 48hs hatchability was 92% for P and 80.3% for F1. Feeding rates (P=54.4%, F1=72.7%) and the average number of eggs per female per week in each generation (P=5.3, F1=16.6) were calculated at the end of the experiment. The vector competence assay showed that Ae. aegypti mosquitoes were positive for ZIKV in body, legs, and saliva.Discussion: Hatchability, feeding rates and the average number of eggs per female in each generation were similar or higher compared to those obtained with other feeding methods for this mosquito species. The effectiveness of the feeder for vector competence studies was demonstrated by obtaining positive results for the infection, dissemination and transmission of ZIKV in Ae. aegypti. Conclusion: These results support the effectiveness of the artificial feeder for mosquito breeding and conducting oral infection studies in Ae. aegypti. We suggest that this method of alimentation could be also employed for other hematophagous insects.