Nipah/Hendra Virus & Fruit Bat Home Range – WHO
# 5716
Over the past month more than a dozen horses in and around Queensland Australia have died from the Hendra Virus – a pathogen normally carried by flying foxes (bats), but that can be transmitted to horses and, on rare occasions, to humans as well.
The virus was first isolated in 1994 after the deaths of 13 horses and a trainer in Hendra, a suburb of Brisbane, Australia. A stable hand, who also cared for the horses, was hospitalized, but survived.
Another outbreak took place in MacKay, 1000 km to the north of Brisbane, the previous month. Two horses died, and the owner was hospitalized several weeks later with meningitis.
He recovered, but developed neurological symptoms and died 14 months later.
Subsequent studies have showed a high prevalence of the newly identified Hendra virus in Pteropid fruit bats (flying foxes) in the region.
In 1999, a very similar virus emerged at a Malaysian pig farm, resulting in 105 human deaths and the culling of one million pigs. Exported pigs caused another outbreak at an abattoir in Singapore, resulting in 11 infections and 1 additional death.
This virus was designated Nipah, named after the place where it was first isolated in humans. It too, is believed to be carried by the fruit bat.
Since then, there have been scattered outbreaks of both viruses in Australia (Hendra virus) and in Bangladesh and adjacent parts of India (Nipah). Of the two, the Nipah virus has infected and killed the most humans.
For more background on these two rare viruses, the CDC’s Special Pathogens Branch maintains a fact sheet:
The World Health Organization maintains a website on the Hendra Virus (Hendra Virus (HeV) Infection) and Nipah Virus (Nipah Virus (NiV) Infection) on their Global Alert And Response (GAR) site.
Today, we’ve news of an unusual discovery out of Australia.
A dog on one of the quarantined ranches in Queensland has tested positive for antibodies to the Hendra Virus. Although the dog appears healthy, this indicates a previous exposure to the virus.
And this marks the first known infection of a dog by the virus in the wild.
The following notice appears on the Queensland Government Primary Industry & Fisheries website:
Current situation as at 26 July 2011
The Australian Animal Health Laboratory (AAHL) in Geelong has confirmed that a dog has tested positive for Hendra virus.
This is an unprecedented situation, and the first time outside a laboratory that an animal other than a flying fox or horse, or a human has been confirmed with Hendra virus infection.
Biosecurity Queensland´s policy is to test cats and dogs on properties where there are infected horses.
The remaining horses and dogs on this property are still being monitored daily and show no signs of illness.
We recommend that people keep dogs and cats away from sick horses to reduce the risk of such an infection happening.
While it is too soon to gauge the impact of this particular discovery, anytime a virus jumps species we tend to pay close attention.
Many of the common illnesses we think of as `human’ diseases actually began in other species, and only later migrated to humans.
Tuberculosis probably jumped to humans when man began to domesticate goats and cattle. Measles appears to have evolved from canine distemper and/or the Rinderpest virus of cattle. And Influenza, as most of you know, is native to aquatic birds.
The list of zoonotic diseases (those shared between humans and animals) is long and continually expanding, and includes: SARS, Babesiosis, Borrelia (Lyme), Nipah, Hendra, Malaria, Hantavirus, Ebola, Bartonella, Leptospirosis, Q-Fever, bird flu and many, many others.
When a virus adapts to a new host, it not only gives it fresh opportunities to mutate and evolve, it provides another potential vector to spread the pathogen.
And when that host is a dog or a cat – animals with whom humans closely interact – the risks of spreading to humans are even greater.
As the following article from the Sydney Morning Herald tells us, in light of this latest discovery scientists are now tasked with determining what – if any – changes may have occurred in the Hendra virus.
Scientists guessing over Hendra dog
Kym Agius, Jessica Marszalek and Petrina Berry
July 26, 2011 - 5:49PMAAP
The first dog to contract the Hendra virus has scientists guessing whether the virus is being transmitted differently or if humans can now catch the disease from canines.
For now, there are far more questions than answers.
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