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Infectious Bovine Rhinotracheitis (IBR)

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Liz is a licensed veterinary medical technologist. She acquired a B.S. in veterinary medical technology from Lincoln Memorial University.

What is IBR?

Infectious Bovine Rhinotracheitis (IBR), also known as "rednose", is a highly contagious, infectious respiratory disease of cattle caused by Bovine Herpesvirus-1 (BHV-1). It does not discriminate in age; it can affect both young and older cattle. It is characterized by acute inflammation of the upper respiratory tract. In addition to respiratory disease, this virus can also cause conjunctivitis (inflammation of the conjunctiva of the eyes), spontaneous abortions (sudden loss of pregnancy), encephalitis (inflammation of the brain), and generalized systemic infections. After initial infection, the virus goes latent in the cow's nervous system, quietly lingering in the nerve cells in the brain for the rest of the cow’s life. During times of disease or general stress on the animal (shipping, calving, etc.), the virus activates and begins to multiply within the nervous system. It is then that the virus may be shed, generally in secretions from the nose and the eyes. Animals that become infected become carriers of the virus for life.

Purchase and introduction of infected animals into uninfected herds is the main source of new infection. Secondary disease and conditions caused by this virus can be serious. Therefore, it is a barrier to international trade; cattle with the BoHV-1antibody cannot be exported to BoHV-1-free countries, nor can they be accepted into artificial insemination (AI) centers.

Respiratory symptoms in a Charolais bull with suspected IBR.

Respiratory symptoms in a Charolais bull with suspected IBR.

Purchase and introduction of infected animals into uninfected herds is the main source of new infection.

Clinical Signs

Clinical signs (symptoms) of IBR include high fever, coughing, purulent (pus-like) nasal discharge, conjunctivitis, and general depression or lethargy. Affected animals may also exhibit loss of appetite, and lesions or hyperemeia (swelling and redness due to excess blood flow) of the mucous membranes.

Affected dairy cows or cows who are nursing may experience significant drops in milk production. Pregnant cows may spontaneous abort, whether they are early or late term. Affected cows and bulls alike may experience problems with infertility.

Conjunctivitis in a calf with IBR.

Conjunctivitis in a calf with IBR.

Clinical signs of IBR include high fever, coughing, purulent nasal discharge, conjunctivitis, and general depression or lethargy.

Treatment

Unfortunately, since this is a viral disease, there is no direct treatment or cure at this time. This means that prevention is key. Known carriers of the virus should be identified and removed from the herd. Culling all affected animals should be considered. Infected, or even possibly affected animals who are asymptomatic (not showing any symptoms), should be isolated from the rest of the herd and treated with antibiotics and anti-inflammatory drugs to treat and prevent secondary infections if necessary.

Since this is a viral disease, there is no direct treatment or cure at this time.

Prevention

Control of this virus is based on the use of vaccines. Since BHV-1 is highly contagious, vaccination is recommended as soon as passive immunity in calves has disappeared; this usually occurs around four to six months of age. Currently available vaccines for IBR include modified live virus (MLV) vaccines and inactivated or killed virus (KV) vaccines. Timing of vaccination is as key as the choice of vaccine; since maximum protection does not generally occur until approximately two to three weeks after vaccination, calves should be vaccinated two to three weeks before weaning, at which time they are subjected to an increased risk of infection due to loss of passive immunity and increased stress from weaning.

IBR marker vaccine.

IBR marker vaccine.

A single vaccination will likely reduce the severity of disease if infected later, but will not provide complete protection. Booster vaccines are therefore strongly recommended, and should be administered per the manufacturer's or veterinarian's recommendation. The use of marker vaccines is highly recommended since the antibodies the vaccines stimulate cannot be distinguished from the BoHV-1 antibody that follows a natural infection; in other words, if tested for the virus later, the animal may test a false positive and be culled or treated unnecessarily. As with any viral, fungal, or bacterial disease, appropriate biosecurity measures should always be in place, and will greatly reduce the risk of transmission to other farms.

Sources

  • Course notes from Large Animal Clinical Disease college courses
  • Personal experience while working in the veterinary industry

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

© 2019 Liz Hardin