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Wednesday 9 July 2008

RAPID ROUNDUP: Hendra virus outbreak: Experts respond

A property in Brisbane has been placed into quarantine after an outbreak of Hendra virus in horses. Below, experts respond.

Feel free to use these quotes in your stories. Further comments are expected and will be posted here as they are received. If you would like to speak to an expert, please don’t hesitate to contact us on (08) 8207 7415 or by email.

Dr Stephen Prowse is CEO of the Australian Biosecurity Cooperative Research Centre for Emerging Infectious Disease.

“Horse owners in eastern Queensland and northern NSW need to be aware that fruit bats carry Hendra virus and they should minimise potential contact between bats and horses in order to reduce the risk of transmission of the disease. If horse owners see fruit bats feeding in trees in the paddocks where they have horses they should either remove the horses or fence off the trees.

It is still not exactly clear how it gets from bats to horses and why horses are so susceptible. When horses are kept in paddocks where fruit bats feed, for example in paddocks with mango or other fruit trees or horses kept in small orchard allotments, what we think happens is that partially eaten fruit, urine or faeces from bats gets in to water or feed troughs and that the virus gets into horses when they eat or drink from those troughs. This is all speculation though as we know that bats carry the virus but we don’t know exactly how it gets into horses.”

Professor John MacKenzie is an expert in infectious disease emergence, at Curtin University, WA.. His laboratory has been interested in understanding the role of fruit bats (flying foxes) in the appearance of novel virus diseases such as Hendra virus.

“The most important thing to keep in mind when you have these outbreaks is that in general terms, there is no great risk to humans. The only way humans get infected is from horses, not from the original reservoir of the virus which is fruit bats. Transmission to humans does not happen very readily. When we were looking into the original outbreak of Hendra virus we looked at a number of bat carers, who were not affected, and we also looked at the people who did the autopsies of horses and none of them were affected either. The virus is not very transmissible from horses to humans. There really needs to be a cut or something similar for the virus to move to humans. There is no major risk to human health other than to people in direct close contact with the horses – if they have a cut which comes into contact with horse blood or nasal discharge there is a slight possibility, but it is not very great. If someone does get infected they are no risk to others as we have no knowledge of any human to human transmission ever occurring.”

Dr Ron Glanville is Chief Veterinary Officer in the Queensland Department of Primary Industries and Fisheries

“This outbreak has occurred at a veterinary practice near Brisbane. A few horses have come down with an unusual sickness and three have now tested positive for Hendra virus. Two of these have been put down, one on Saturday and one on Tuesday. The third has relatively mild neurological signs and seems to be recovering. We have investigations underway to find out what has happened. We have quarantined the property, disinfection procedures are in place and we are testing other horses on the property. Qld health are also involved as it is a zoonotic disease so people in the vet practise have concerns about their own health.”

Are we likely to see another an outbreak like equine influenza and a lock down of the horse industry? The answer is no. This is a virus that is not highly contagious between animals. We know from past outbreaks that it requires close contact between horses or mechanical spread of viruses between horses to get transmission. It is not the sort of virus that is likely to cause an outbreak which spreads through the horse population. We have a quarantine in place but we are not going to impose a lockdown on the horse industry as we did with equine influenza.”