Hendra virus

Faced with a sick horse, veterinarians’ primary concern is to treat the animal, get him well again, and prevent disease spread in the meantime. But when the horse’s illness presents a health threat to people, as well, priorities can change. Human health and safety move to the forefront, with the veterinarian serving in the important role of educating clients.

The trouble is, horse owners don’t always listen. So Australian researchers recently examined how to effectively stress the importance of the risks associated with Hendra virus, a deadly zoonotic disease that emerged on the east coast of Australia in the 1990. Zoonotic diseases are those than can transfer between animals and humans.

Hendra virus is carried by flying foxes, Australian fruit-eating bats endemic to tropical and sub-tropical regions. Horses get it by inadvertently ingesting infected droppings or bodily fluids, and humans contract it when handling infected equine patients.

Diana Mendez, BVSc equ, MPH, a research officer at James Cook University, in Townsville, Queensland, said that since 1994, Hendra virus has “spilled over” from flying foxes to horses on at least 56 occasions and in seven instances to humans.

“Transmission from horses to humans is via exposure to bodily fluids, including blood, from an infected horse, which may have been shedding viral Hendra particles two days before developing clinical signs,” Mendez said. “Although infection is rare, the mortality rate is 57% in humans, hence its health and safety significance for veterinarians and horse owners.”

The seven people who have had Hendra virus included four veterinary personnel (two died, two survived), a horse trainer (died), a stable hand (survived), and a horse owner (died). Under Australian law, a veterinarian treating an animal is responsible for the health and safety of all people present.

“When a horse is suspected of (having) Hendra, veterinarians are mandated to notify the biosecurity authorities; and while awaiting field support from these authorities, they need to inform horse owners about the risks involved and, if necessary, instruct them about infection control strategies to mitigate these risks,” Mendez said.

For the study, she interviewed veterinarians regarding their experience in communicating with horse owners.

“Different horse owners had different responses,” she said. “While some were receptive to information and safety directives regarding Hendra-related risks to animal and human health, others were reportedly unreceptive.”

The veterinarians cited various reasons for horse owners’ lack of responsiveness, including:

  • Exposure had already occurred (therefore, clients didn’t consider it worthwhile to use personal protective equipment);
  • Risk was not properly understood or was denied;
  • Skepticism about the risk within the rural culture;
  • Cost of infection control and/or Hendra virus testing;
  • Fear of long-term detrimental effect to personal or business reputation; and
  • Clients’ emotional states.

“In our studies, vets reported that a lack of cooperation from some clients hampered their efforts to follow official guidelines when managing a potential outbreak,” Mendez said. “Some vets went further and stated that these communication issues prevented them from fulfilling their workplace health and safety and biosecurity legal responsibilities.

“In some instances, a vet is left with no alternative other than to leave the property and not treat the horse, to protect their own safety and legal liability,” she added. “But that’s not really a solution, as it leaves the horse untreated and the horse owner at risk of infection.”

Although Hendra virus is confined to a relatively small area of Australia, Mendez believes other countries can learn from the Australian experience. Almost three-quarters of emerging infectious diseases are zoonoses, so vets are likely to find themselves in similar situations elsewhere.

“The emergence of Hendra in Australia required a change in attitude and it didn’t happen fast enough,” she said. “If another country experienced a similar emerging zoonotic disease, the veterinary workforce needs to be ready to deal with infection control, disease risk, and communication.”

The bottom line for horse owners, the researchers concluded, is that they need to listen to their veterinarians in these situations; vets have expertise and responsibilities that must be respected.

“When you are in a situation where people’s lives are at stake, it’s a bit different from normal veterinary practice,” Mendez said. “The vet has a different role than the normal service provider model as he or she takes on a biosecurity and public health role to manage a crisis.

“It’s about the safety and health of people and animals,” she said

The study, “Difficulties experienced by veterinarians when communicating about emerging zoonotic risks with animal owners: the case of Hendra virus,” was published in BMC Veterinary Research.