Bovine malignant catarrhal fever

Malignant catarrhal fever The (BKF, also head Malignant disease, Coryza gangrenous, gangrenous rhinitis ) is an acute, usually fatal viral disease of ruminants that are characterized by inflammation of the mucous membranes, especially of the head, expresses. It is only slightly contagious, so ill just individual animals in general.

Occurrence

Malignant catarrhal fever This was first observed in 1877 in Switzerland. 1923 was identified as a viral disease.

The disease occurs worldwide and infects mainly cattle, but also buffalo, goats, chamois, ibex, elk, reindeer and giraffes are susceptible. Individual cases should also occur in sheep. The virus reservoirs are in Africa, the wildebeest and in Europe the sheep infected each inapparent clinically, virus- excreting main or primary hosts into consideration.

On malignant catarrhal fever usually ill just older individual animals (> 2.5 years) of a herd, in different areas, the disease is enzootic, but diseases sometimes occur with large time interval. Chance of a epizootic occurrence was observed.

Pathogens and transmission

At least two pathogens are responsible for the disease, with symptoms and clinical signs in affected animals are equal:

Alcelaphines herpesvirus type 1 (AHV -1): It is the trigger of the so-called " Wildebeest -associated " BKFs. This form can be found within Africa. Reservoir are wild ruminants ( buffalo, wildebeest, etc.). The reservoirs are lifelong latently infected and transmit the virus to their offspring. The virus is excreted by the infected pups about nasal and eye discharge. Cattle put on by droplet infection or contaminated food / water.

Ovine herpesvirus type 2 ( OHV2 ): This virus has not yet been classified accurately. It is the trigger of the so-called " sheep -associated " BKFs. This form is found outside of Africa. The manner of transmission of sheep to cattle has not yet been finally resolved, probably is but the inclusion of contaminated food or water. This requires a close contact of cattle and sheep. Especially lamb mother sheep play a big role here. In sheep, the virus triggers hardly clinical symptoms. Cattle and deer are considered faulty hosts. A transfer of cattle to cattle is extremely rare.

Clinic

The incubation period is 14 to 150 days. There are four different forms of the disease:

• Peracute form
• Head -eye shape
• Intestinal form.
• Mild form

Early symptoms include fever over 40 ° C, muscle tremors, lethargy, Pansenatonie ( failure of Pansenmotorik ), drying up of milk, increased breathing and heart rate ( tachycardia). In the peracute form can already enter the death.

From the first or second day of illness occurs in the head and eye shape to swelling of the mucous membranes of the head. The inflammation of the conjunctiva leads to increased lacrimation and the swell up of the eye. She grabs later on the average eyeball ( iridocyclitis ) and can lead to rupture of the eyeball. The nasal discharge is watery at first and later due to secondary bacterial infections interspersed with pus and fibrin. Due to the swelling of the airways and the breathing is impaired can cause choking. The swelling can spread to the lower respiratory tract and lead to a croupous pneumonia with severe cough. A spread of the inflammation to the sinuses (sinusitis) can lead to loosening of the horns. The inflammation of the oral mucosa leading to initial redness to diphtheria -like coverings, in solving them remain heavily reddened erosions. Feed intake is greatly reduced by these painful processes. In a spread to the mucosa of the gastrointestinal tract ( intestinal form) it can cause inflammation of the stomach ( Ruminitis, gastritis ) and the intestine (enteritis ) with colic, diarrhea or constipation occur. The mild form is characterized by an attenuated disease with few erosions in the mouth and nasal mucosa.

In addition to the diseases of the head mucous membranes it is not uncommon also to similar changes in the mucous membranes of the genitals. Finally, the skin ( neck, back, udders, hooves gap) may be affected.

Often develop in the head and eye shape and central nervous symptoms: it can excitation, incoordination and epileptic-like seizures. Finally, it may come to the coma.

The differential diagnosis is primarily the foot and mouth disease, rinderpest, mucosal disease and bluetongue important.

Prognosis and therapy

The prognosis is very bad for the diseased animal. In perakutem course or spreading to the gastrointestinal tract ( intestinal form ), there is always death. Overall, the mortality rate is over 90%. No specific treatment is not available. Symptomatic treatment may be tried, but is not very promising.