Investigation procedures for Hendra Virus

Hendra virus (HeV) can cause a wide range of clinical signs in horses and serious illness in humans.

If Hendra virus is suspected:

• take immediate steps to minimise exposure to the horse
• contact your nearest Agriculture Victoria Animal Health and Welfare staff, or
• call the Emergency Animal Disease Hotline on 1800 675 888.

There are two case definitions for horses in Victoria where HeV infection is suspected. They are termed 'suspect cases' and 'surveillance cases'.

A horse should be considered a suspect case if it has all the following:

• known, or likely, exposure to flying foxes
• clinical signs and history are consistent with Hendra virus infection
• not currently vaccinated against Hendra virus.

Horses that have had close contact (within 5 meters) with a suspect or infected horse, or with a contaminated environment, should also be treated as suspect cases.

Examples of factors that may increase suspicion of Hendra virus in horses include:

• recent travel from a Hendra-affected area
• sudden or unexplained death
• unexplained illness with rapid deterioration.

Suspect cases require immediate isolation and urgent assessment.

A horse may be classified as a surveillance case when all of the following apply:

• it does not meet the ‘suspect case’ definition
• it shows clinical signs consistent with Hendra virus
• Hendra virus is one of several possible diagnoses
• the veterinarian considers another diagnosis is more likely than Hendra virus.

• your local District Veterinary Office
• the Emergency Animal Disease Hotline on 1800 675 888.

The investigation of 'suspect' cases of Hendra can be subsidised through Significant Disease Investigation (SDI) Program funding. Surveillance cases are not eligible for SDI funding, but Agriculture Victoria will fund the laboratory testing for Hendra virus.

Hendra virus testing can detect both known genotypes of Hendra virus.

Agriculture Victoria animal health and welfare staff will assist private veterinarians in managing HeV investigations.

Restrict access to suspect or infected horses to essential personnel only.

When contact with the horse is necessary, wear appropriate personal protective equipment (PPE):

• impervious boots (e.g., gumboots)
• overalls
• gloves
• safety glasses or goggles
• P2 respirator mask.

See Guidelines for veterinarians handling potential Hendra virus infection in horses, prepared by DAFF Queensland, for details.

Where possible, clean and disinfect all areas and equipment that may have been exposed to HeV.

Do not perform necropsies until Hendra virus is excluded.

PPE is mandatory for everyone involved in handling or sampling live or dead horses.

The following samples are recommended for Hendra virus testing:

• nasal swabs in viral transport media. Oral and rectal swabs may also be used
• 10 mL blood in EDTA tubes
• 10 mL blood in plain (clot) tubes
• urine-soaked swab collected immediately after urination.

Samples should only be collected from horses if exposure risk can be managed.