Malignant catarrhal fever

from Wikipedia, the free encyclopedia
Head and eye shape of the malignant catarrh half fever

The Malignant catarrhal fever (BKF, even Malignant head disease , coryza gangraenosa , rhinitis gangraenosa ) 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 that usually only individual animals become ill.

Occurrence

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

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

Malignant catarrhal fever usually only affects older individual animals (> 2.5 years) in a herd; in various areas the disease is enzootic , although diseases sometimes occur with a long time lag. Occasionally an epizootic occurrence was also observed.

Pathogen and transmission

At least two pathogens are held responsible for the disease, with symptoms and clinical changes being the same in the animals concerned:

Alcelaphine herpesvirus type 1 (AHV-1): It is the trigger of the so-called " Wildebeest -associated" BKF. This form can be found within Africa. Reservoir are wild ruminants (buffalo, wildebeest, etc.). The reservoirs are latently infected for life and transmit the virus to their offspring. The infected pups excrete the virus through nasal and eye discharge. Cattle become infected via droplet infection or contaminated feed / water.

Ovine herpesvirus type 2 (OHV2): This virus has not yet been precisely classified. It triggers the so-called "sheep-associated" BKF. This form occurs outside of Africa. The mode of transmission from sheep to cattle is not yet fully understood, but the ingestion of contaminated feed or water is likely. The prerequisite is close contact between cattle and sheep. Lamb ewes in particular play a major role here. The virus hardly causes clinical symptoms in sheep. Cattle and deer are seen as false hosts. Transmission from beef to beef is extremely rare.

clinic

The incubation period is 14 to 150 days. Four types of disease can be distinguished:

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

Early symptoms are fever above 40 ° C, muscle tremors , indifference, rumen atony (failure of rumen motor skills ), drying up of milk, increased breathing and heart rate ( tachycardia ). In the peracute form, death can already occur.

Conjunctivitis in a cow with malignant catarrhal fever
Salivation and inflammation of the lining of the nose

From the first or second day of illness, the head-eye shape causes swelling of the head mucous membranes. The inflammation of the conjunctiva leads to increased tear flow and the swelling of the eye. It later spreads to the middle skin of the eye ( iridocyclitis ) and can cause the eyeball to break open. The nasal discharge is initially watery and later, due to secondary bacterial infections, purulent and riddled with fibrin . The swelling of the airways makes breathing difficult and can lead to attacks of suffocation. The swelling can also spread to the lower airways and lead to croupy pneumonia with a strong cough. If the inflammation spreads to the frontal sinus ( sinusitis ), the horns can loosen . The inflammation of the oral mucosa leads, after the initial reddening, to diphtheria- like deposits, which, when dissolved, leave behind strongly reddened erosions . These painful processes greatly reduce feed intake. If it spreads to the mucous membrane of the gastrointestinal tract (intestinal form), inflammation of the stomach ( ruminitis , gastritis ) and the intestine ( enteritis ) with colic , diarrhea or constipation can occur. The mild form is characterized by a weakened clinical picture with few erosions in the oral and nasal mucosa.

In addition to diseases of the head mucous membranes, it is not uncommon for similar changes to occur in the mucous membranes of the genitals . Finally, the skin (neck, back, udder, cleft claws) can also be affected.

Often-eye form head also develop central nervous symptoms when: it can arousal, balance disorders and epilepsy -like seizures. Eventually a coma can occur.

In terms of differential diagnosis, foot-and-mouth disease , rinderpest , mucosal disease and bluetongue are particularly important.

Prognosis and therapy

The prognosis for the sick animal is very bad. In the case of a peracute course or spreading to the gastrointestinal tract (intestinal form), death always occurs. Overall, the death rate is over 90%. There is no specific therapy . Symptomatic treatment can be tried, but is not very promising.

literature

  • E. Benndorf: Malignant catarrhal fever. In: J. Beer (ed.): Infectious diseases of domestic animals. 2nd Edition. Gustav Fischer, Jena 1980, pp. 235-239

Web links

Commons : Malignant Catarrhal Fever  album with pictures, videos and audio files