Horses are at increased risk of Hendra virus (HeV) infection at this time of year, the Australian Veterinary Association (AVA) has warned. The disease is usually fatal, and can affect humans that have been in contact with affected horses.
The virus is named after the suburb of Brisbane, Queensland, Australia, in which it was first isolated. In that outbreak in horses at a training centre, 14 horses died. Seven other horses were shown to have been infected and were humanely destroyed. Affected animals typically showed severe lung damage. Two humans were affected, one of whom died.
The natural hosts for the Hendra virus (HeV) are species of fruit bats (commonly known as flying foxes). Antibodies have been found in all four species of fruit bats found in mainland Australia.
“Anyone working with horses should be on the lookout and immediately report any suspected cases of Hendra virus infection over the coming months,” said Dr Barry Smyth, Vice-President of the Australian Veterinary Association.
“Recent mass movements of large flying fox colonies means owners should be especially vigilant.
“Wet weather in some parts of the country has caused flying foxes to take to the air to find food in new areas. An influx of more than 130,000 into Victoria was confirmed by scientists just last week.
“So far cases of Hendra infection have been restricted to Queensland and New South Wales, however there is a potential for the disease wherever there are flying foxes.
Common signs to look out for include respiratory distress, frothy nasal discharge, elevated body temperature (above 40° C) and elevated heart rate. Some horses may show neurological signs including incoordination and head pressing. However, it is important to realise there are no specific signs of infection.
What can you do to limit the risk of horses being exposed to the virus? “Protective measures include placing feed and water under cover where possible, not placing feed and water under trees when flying foxes are in the area, not using feed that might attract flying foxes (such as fruit and vegetables), and where possible removing horses from fields where flying foxes are active, and fencing off trees where flying foxes roost” Dr Smyth said.
The few cases of human Hendra virus infection have been the result of very close contact with horses infected with the virus. Body fluids or secretions from infected animals are likely to contain the virus.
At the time the people became infected the horses did not appear sick.
“The risk can be greatly reduced by adopting good hygiene practices as a matter of routine and taking increased precautions around any sick horse,” said Dr Smyth.