The pathogen, bovine herpes virus 1 (BHV-1), causes various diseases in cattle: Infectious Bovine Rhinotracheitis (IBR), Infectious Pustular Vulvovaginitis (IPV) and Infectious Balanoposthitis (IBP). There is no risk of infection for humans.

worldwide

The main hosts are cattle. Natural infections (but usually without clinical manifestations) have been reported in sheep and goats. Wild ruminants also appear to be susceptible to BHV-1 infection.

Transmission occurs through direct contact from animal to animal. Indirect transmission through people and contaminated clothing, transport vehicles and equipment (stable utensils) is also possible.

2 to 6 days

An infection with bovine herpes virus 1 can manifest itself in two forms: As IBR (= respiratory form) with, among other things, fatigue, unwillingness to eat, fever (up to 42 °C), nasal discharge, cough or as IPV / IBP (= genital form). Clinical symptoms may be absent or only slightly pronounced in an infection of adult cattle.

There is no therapy

IBR/IPV/IBP is a notifiable animal disease. In case of suspicion of disease, the legal requirements must be followed. Vaccination is prohibited in Austria.

Since 1999, Austria has had the status of "disease-free" in accordance with Implementing Regulation (EU) 2021/620 (formerly Directive 64/432/EEC official additional guarantees). In order to maintain this status, annual surveillance programmes are carried out in accordance with national legislation.

On 12 June 2022, four imported cattle were found to be IBR/IPV-infected on the basis of recruitment tests on a farm in Lower Austria. The BHV-1-infected animals were slaughtered in accordance with animal welfare regulations. Early detection of the infection prevented it from spreading and no other Austrian farms or cattle were affected.

The pathogen, Bovine Herpes Virus 1 (BoHV-1) with various subtypes, is a double-stranded DNA virus and belongs to the Herpesviridae family.

The pathogen is usually introduced into BHV1-free farms via the purchase of animals that are clinically healthy but carry the virus latently or are in the incubation phase. The spread of the disease is promoted by intensive animal movements, e.g. through livestock dealers and livestock markets.

The pathogen spreads in the herd mainly through direct animal contact, e.g. via tear and nasal secretions containing the pathogen (droplet infection), via the mucous membranes of the genital tract, but also via faeces. Indirect transmission through people and contaminated clothing, through inadequately cleaned, contaminated transport vehicles, equipment (stable utensils) and instruments (e.g. injection needles) is also possible. Compliance with biosecurity and hygiene measures is relevant in order to prevent the introduction and spread of the pathogen.

Infected animals remain virus carriers for the rest of their lives and can become shedders again in phases after a stressful situation (e.g. change of feed, birth, transport, stress). Nasal virus excretion lasts up to 2 weeks. Male animals play an important role in the spread of IBR/IPV/IBP (transmission of infected semen!).

The affected cattle show serologically detectable antibodies 7-14 days after infection. Maternal antibodies are transmitted to the calves via colostrum, which provides them with biological protection against clinical disease. They are usually detectable up to 9 months, in a few cases even longer.

Small ruminants can become infected and excrete the virus, but do not show any symptoms of the disease. Wild ruminants form a virus reservoir in BHV-1 areas.

Symptoms

There are two forms of BHV-1 infection and the symptoms vary depending on the age of the infected animals:

IBR = respiratory form: Fatigue, reluctance to eat, fever (up to 42 °C), nasal discharge, hyperaemia of the nasal and mucous membranes of the mouth ("red nose symptom"), conjunctivitis, coughing, dyspnoea, abortion. Fattening animals show reduced fattening performance. Lactating animals show a sharp drop in milk yield right at the beginning of the disease. In calves, IBR primarily progresses as a febrile general illness with predominance of respiratory symptoms and often diarrhoea. The mortality rate is significantly higher than in adult animals.

IPV/IBP = genital form (usually limited to the vaginal and preputial mucosa): Fatigue, reluctance to eat, fever (up to 42 °C), labia swollen and oedematised, mucous membrane (vestibule, vagina, penis) hyperaemic, vesicles on the mucous membrane, abortion, orchitis, endometritis.

Sample material for indirect detection (ELISA, serum neutralization test):

• Whole blood or serum without anticoagulant (not frozen, filling volume > 7ml).
• Tank milk or single milk

Sample material for direct detection (PCR, virus cultivation)

• Nasal swab, eye swab, genital swab
• Head incl. tonsils and larynx
• esophagus 20 cm

altered organs:

• fist-sized piece of lung
• Lymph nodes
• Uterus, ovaries
• organs from fetus and placenta