THE discovery of a rare but highly contagious virus which has killed pigeon flocks in Victoria does not pose a major risk to humans, experts say.
Several pigeons have died and a number of properties in northern Victoria have been quarantined amid Australia’s first outbreak of avian paramyxovirus (APMV) in pigeons.
While people who handle infected birds and those with suppressed immune systems face the greatest risk of contracting APMV, it usually causes only mild flu-like symptoms or conjunctivitis.
Influenza Specialist Group chairman Alan Hampson said APMV was unlike avian influenza virus, or bird flu, which can prove fatal in humans and birds.
"(APMV) are in a completely different group of viruses altogether," Dr Hampson told AAP.
"It rarely transmits to humans, and when it does only causes mild illness … possibly a bit of conjunctivitis.
"but it’s very rare to be a human infection and rare to be anything but trivial.
"So it’s in a different ballpark from avian flu."
APMV is usually transmitted between birds via their droppings or respiratory secretions.
There are believed to be nine different known types of APMV, ranging from APMV-1 to APMV-9, and scientists are yet to determine the one involved in the Victorian outbreak.
The group of viruses that make up APMV-1 includes Newcastle disease, a highly contagious ailment which affects all birds and has previously infected Australian poultry.
While avian paramyxoviruses are not considered dangerous to people, the death of a 42-year-old man in the US was linked to Newcastle disease.
A study published in the Journal of Virology by American health authorities in 2007 said APMV-1 was found in lung tissue taken from the man during an autopsy.
The man, who had a history of non-Hodgkin’s lymphoma, developed a lethal case of pneumonia after a blood stem cell transplant from an unrelated donor.
"this is the most completely documented case of a systemic human infection caused by APMV-1, and it is the first report of an association of this virus with a fatal disease in a human," the study said.
Pigeons as well as chickens, turkeys, ducks, geese, ostriches, quails, guinea pigs, crows and other species of wild and caged birds are considered natural hosts for Newcastle disease.
Newcastle disease, which was first discovered in 1926, is endemic to many countries in Africa, Asia, Central America and South America.
According to the Australian Wildlife Health Network, mild strains of Newcastle disease are present in wild bird populations across Australia.
However, no deaths have been reported in wild birds.
Dr Hampson said if tests revealed the virus from which the Victorian pigeons died was Newcastle disease, pigeon culls could be carried out to stop it spreading to poultry.
"If it is Newcastle disease, it will be of concern to the Department of Agriculture," he said.