Bovine Herpes Virus 1
Situation in Austria
On 12.6.2022, four imported cattle were found to be infected with IBR/IPV as a result of recruitment tests at a farm in Lower Austria. Due to the excellent cooperation between the involved agencies, necessary measures were taken immediately. The infected animals were slaughtered in accordance with animal welfare regulations. All further investigations in the herd proved negative, and no other Austrian farms or cattle were affected. Early detection of the infection prevented it from spreading.
Since 1999, Austria has been officially recognized as free of IBR/IPV. To maintain this status, surveillance programs are carried out annually in accordance with the requirements of Directive 64/432/EEC and national legislation.
The pathogen, Bovine Herpes Virus 1 (BoHV-1) with various subtypes, is a double-stranded DNA virus and belongs to the Herpesviridae family. Introduction of the pathogen into BHV1-free farms usually occurs through 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 movement through, for example, livestock traders and livestock markets. The pathogen is spread in the herd mainly by direct animal contact, e.g. via pathogen-containing tear and nasal secretions (droplet infection), via the mucous membranes of the genital tract, but also via feces. Indirect transmission through persons and contaminated clothing, through insufficiently cleaned, contaminated transport vehicles, equipment (stable utensils) and instruments (e.g. injection needles) is also possible. Infected animals remain virus carriers for life and can become excretors 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 (sending infected semen!). Affected cattle show serologically detectable antibodies 7-14 days after infection. Maternal antibodies are transmitted via colostrum to the calves, which thus have a biological protection against clinical disease. They are usually detectable until 9 months of age, in a few cases longer. Small ruminants can become infected, excrete the virus, but show no symptoms of disease. Wild ruminants form a virus reservoir in BHV-1 areas.
There are two forms of BHV-1 infection, the symptoms of which vary according to the age of the infected animals:
IBR = respiratory form: Dullness, reluctance to eat, fever (up to 42 °C), nasal discharge, hyperemia of the mucous membranes of the nose and fauces ("red nose symptom"), conjunctivitis, cough, dyspnea, abortion. Fattening animals show decreased fattening performance. Lactating animals show a severe decrease in milk yield early in the disease. In calves, IBR progresses primarily as a febrile general disease with dominance of respiratory symptoms and often diarrhea. The lethality is significantly higher than in adult animals.
IPV/IBP = genital form (usually confined to the vaginal and preputial mucosa): dullness, reluctance to feed, fever (up to 42 °C), labia swollen and edematous, mucosa (vestibule, vagina, penis) hyperemic, vesicles on the mucosa, 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
- fist-sized piece of lung
- Lymph nodes
- Uterus, ovaries
- organs from fetus and placenta
Last updated: 10.10.2023