The potential of house flies to act as a vector of avian influenza subtype H5N1 under experimental conditions.
The objective of the present study was to determine the potential for house flies (Musca domestica L.) (Diptera: Muscidae) to harbour the avian influenza (AI) H5N1 virus. Laboratory-reared flies were experimentally fed with a mixture containing the AI virus. Exposed flies were washed with brain-heart infusion broth and followed by 70% alcohol before preparation of whole fly homogenate. The homogenate was inoculated into six 10-day-old embryonated chicken eggs (ECEs). Allantoic fluids were collected to determine the virus using the haemagglutination (HA) test, reverse transcription-polymerase chain reaction (RT-PCR) or quantitative real-time RT-PCR (RRT-PCR). In the first experiment, ECEs that were inoculated with the 50 AI virus exposed fly homogenates died within 48 h and HA and RT-PCR were positive for AI virus. In the second experiment, ECEs that were inoculated with only one fly died with positive HA test and RT-PCR. In the last experiment, a group of exposed flies was collected at 0, 6, 12, 24, 36, 48, 72 and 96 h post-exposure. Fly homogenates of each time point were tested by virus titration in ECEs and RRT-PCR. Virus titres declined in relation to exposure time. Furthermore, RRT-PCR results were positive at any time point. The present study shows that the flies may harbour the AI virus and could act as a mechanical vector of the AI virus.
Department of Veterinary Medicine, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand.
S
S
Wanaratana
S
S
Panyim
S
S
Pakpinyo
D000818:Animals; D002642:Chick Embryo / Q000821:virology*; D002645:Chickens; D006386:Hemagglutination Tests / Q000662:veterinary*; D006793:Houseflies / Q000821:virology*; D053124:Influenza A Virus, H5N1 Subtype / Q000302:isolation & purification*; D005585:Influenza in Birds / Q000635:transmission*; D007303:Insect Vectors / Q000821:virology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013785:Thailand