# 975
Today we get a follow up report from Worldpoultry.net that appears to confirm long held fears that flies could be vectors of the avian flu virus. Last January I ran a piece entitled Cat and Dogs and Flies, Oh My! about this possibility, and earlier this week we discussed it here.
In 2004, researchers in Kyoto, Japan determined that blowflies could carry the AI virus internally, and there has always been the suspicion that flies could carry infected material from place to place as mechanical vectors. Simply put, a fly lands on infected poultry droppings, and then buzzes off with a viral payload attached to its feet.
This from the Department of Medical Entomology, National Institute of Infectious Diseases, Tokyo, Japan
The H5 influenza A virus genes were detected from the intestinal organs, crop, and gut of the two blow fly species, Calliphora nigribarbis and Aldrichina grahami, by reverse transcription-polymerase chain reaction for the matrix protein (M) and hemagglutinin (HA) genes. The HA gene encoding multiple basic amino acids at the HA cleavage site indicated that this virus is a highly pathogenic strain. . . . . Our results suggest it is possible that blow flies could become a mechanical transmitter of H5N1 influenza virus.
While it appears possible for flies to be vectors, what we don't know is how often this happens in the real world. It may, however, help explain how the virus can spread despite bio-containment efforts, and might even explain some of the human cases with no direct contact with poultry.
Houseflies can transmit the bird flu
// 13 Jul 2007
The common housefly feeds and breeds on all kinds of organic matter, including food, animal feed, garbage, faeces and animal carcasses. Could these creatures transmit bird flu?
On farms, houseflies constantly move between dirty areas with pathogens and clean areas, such as feed storage and animal housing. Due to this nature of movement, houseflies have been implicated in the transmission of different types of diseases caused by bacteria, protozoan and viral parasites.
Bird flu is no exception
Research conducted at North Carolina State University in the US shows that these houseflies can indeed transmit the AI virus . According to the researchers, “more than one-third of the adult Musca domestica sampled contained AI virus particles”.
Led by Wes Dawson and James Guy, the researchers said adult flies carried an infectious dose in their gut for more than three hours after feeding. “This might be important for spread of the virus when fly populations are high and in contact with highly virulent strains,” they explained.
Flies can spread Newcastle Disease
The researchers added that houseflies could also transmit the Newcastle Disease in poultry. They explained that the hazards are focused on housefly feeding or sucking up liquid from putrefying food and feaces supporting high concentrations of pathogen.
To support their point, they noted that houseflies were well established vectors of food poisoning bacteria like Salmonella .
“This is why, more recently, transmission of poultry virus diseases like Newcastle disease and avian influenza by houseflies is considered in addition to spread by direct contact, contaminated feaces and bird secretions."
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