Bovine pestivirus or bovine viral diarrhoea virus (BVDV) and mucosal disease in cattle

Page last updated: Thursday, 14 February 2019 - 4:46pm

Please note: This content may be out of date and is currently under review.

Market access and BVDV

Some live export markets are sensitive to recent evidence of BVDV infection. Many cattle live export markets require certification that Australia is free from BVDV type 2.

BVDV can resemble emergency diseases

Certain emergency diseases not present in Australia have similar signs to BVDV infection in cattle. If any of these diseases became established here, market access for animals and animal products could be severely impacted. Early diagnosis of exotic disease is vital to allow rapid eradication and re-establishment of market access.

If you see any unusual signs of diseases, abnormal behaviour or unexpecting stock, including signs that look like BVDV, call your local vet, a Department vet or the Emergency Animal Disease hotline on 1800 675 888.

Important diseases that look like BVDV and mucosal disease:

foot-and-mouth disease (FMD) ‑ reportable disease
bovine viral diarrhoea virus Type 2 (BVDV-2) ‑ reportable disease
malignant catarrhal fever (wildebeest associated) ‑ reportable disease
vesicular stomatitis ‑ reportable disease
bluetongue virus ‑ reportable disease
bovine popular stomatitis
oral actinobacillosis (woody tongue, wooden tongue).

Summary and more information

For more information about BVDV, contact your local DPIRD vet by visiting Livestock biosecurity program contacts or a private vet.

BVDV is a complex disease. The tables below summarise some of the important information about the disease.

Table 1 - Different BVDV disease statuses

Naive	Never infected Cattle that have never been infected or challenged by BVDV. They have no immunity to the virus.
Immune	Have been infected but are not carriers Cattle that have been infected with BVDV but are not carriers. They have lifelong immunity to future infections. There are two ways this immunity can occur: infection as BVDV circulates through the herd (‘natural immunity’) vaccination.
Persistently infected (PI)	Carriers Carriers of BVDV shed the virus for their entire life. They exhibit variable signs and degree of disease and most die 1–2 years after birth. If a PI cow manages to get pregnant, the calf will also be persistently infected. PI bulls are also potent spreaders of BVDV.

Naive

Never infected

Cattle that have never been infected or challenged by BVDV.

They have no immunity to the virus.

Immune

Have been infected but are not carriers

Cattle that have been infected with BVDV but are not carriers.

They have lifelong immunity to future infections.

There are two ways this immunity can occur:

infection as BVDV circulates through the herd (‘natural immunity’)
vaccination.

Persistently infected (PI)

Carriers

Carriers of BVDV shed the virus for their entire life.

They exhibit variable signs and degree of disease and most die 1–2 years after birth.

If a PI cow manages to get pregnant, the calf will also be persistently infected. PI bulls are also potent spreaders of BVDV.

Table 2 - Signs of BVDV

Poor fertility	low calving rates high rate of pregnancy tested not in calf cows (PTNIC)
Reproductive abnormalities	abortions stillbirths mummified foetuses congenital deformities and defects calves that die soon after birth
Outbreaks of disease	fever not wanting to eat dullness lethargy recovery usually takes a few days pneumonia, scours or other disease, particularly if other stress factors are present. Production losses can be high.
Mucosal disease	fever and lethargy lameness ulcers and drooling from the mouth and nose persistent, profuse, watery diarrhoea that may be bloodstained or contain mucus. It does not respond to drenching. ulcers of the vulva and skin between the claws of all four feet.

Table 3 - The effect of BVDV according to pregnancy status


Non-pregnant naïve cattle	2–3 week infection short-term immune suppression lifelong immunity to BVDV following infection
Pregnant naïve cattle	1–4 months gestation 2–3 week infection embryo death, abortions, stillbirths, mummified foetuses any live calves are persistently infected 4–5 months gestation 2–3 week infection abortions, viable or non-viable calves delivered at full term congenital deformities and defects some calves born normal and immune to BVDV 5–9 months gestation until birth 2–3 week infection abortions any calves born alive at full term immune to BVDV

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