Infectious Bovine Rhinotracheitis

Cause
Diagnosis
Treatment and Control
Other Links

Introduction

Infectious Bovine Rhinotracheitis (IBR) is a highly contagious, infectious disease that is caused by Bovine Herpesvirus-1 (BHV-1). In addition to causing respiratory disease, this virus can cause conjunctivitis, abortions, encephalitis, and generalized systemic infections. IBR was originally recognized during the early 1950s in feeder cattle in the western US. The IBR virus can persist in clinically recovered animals for years. The virus remains inactive until the animal is placed under stress. The virus is shed in secretions from the eye nose and reproductive organs. The clinical diseases caused by the virus can be grouped into: 1) respiratory tract infections 2) eye infections 3) abortions 4) genital infections 5) brain infections 6) generalized infections of newborn calves.

Cause

IBR is caused by Bovine Herpesvirus-1 that is capable of attacking many different tissues in the body leading to a variety of clinical diseases as listed above. Abortions caused by IBR can be caused by exposure to a natural disease strain or exposure of non-protected pregnant cows or their calves with modified live IBR vaccine. In the first case, the virus replicates in the respiratory tract and circulates in the blood, crossing the placenta into the fetus. The virus begins to multiply in the fetus causing death 1-3 days after replication begins. Abortion occurs 2-7 days after death of the fetus. The time from infection of the cow to abortion can range from 18 days to 3 months (abortions occur during the 6th to 9th month). In the second case, modified viruses replicate in non-protected pregnant cows and pass through the placenta into the fetus causing infection and death.
The genital form of IBR is seen in mature cows and bulls and is called Infectious Pustular Vulvovaginitis (IPV). The time course of the infection is 2-3 weeks and respiratory symptoms and abortions do not occur.

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Diagnosis

Although clinical findings of respiratory disease,abortion or IPV may be highly suggestive of IBR, there is no definitive clinical diagnosis for IBR. Laboratory confirmation is necessary in order to identify BHV-1 infection. Measurement of antibody in serum, plasma or milk confirmations exposure to BHV-1.

The symptoms of IPV in females are:

  • A thick white-brown colored vulvular discharge
  • Swollen, reddened vulva
  • Small pus-filled pimple in the lining of the vulva and vagina
  • Loss of the desire to mate
  • Excessive tail switching
  • Frequent urination

Pustules and discharge are observed on the bull’s penis and prepuce.

Treatment and Control

As with other viral diseases, there is no direct treatment for the infection. Antibiotic treatment of secondary infections may be necessary. The best way to control IBR is to vaccinate before a disease outbreak occurs (replicating or non-replicating vaccines) although there are fast acting intranasal vaccines that will confer short-lived immunity.

Other Links

Infectious Bovine Rhinotracheitis - Texas AM University

YouTube Video on IBR

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