Maedi-Visna
Maedi-Visna is an infectious disease in sheep and goats caused by the Maedi-Visna virus (MVV) . "Maedi" and "Visna" are derived from Icelandic names ( Icelandic : mæði , " shortness of breath " and visna , "tiredness"). This retrovirus causes chronic diseases of both the lungs ( Maedi ) and the central nervous system ( Visna ) in sheep . Furthermore, in rare cases, chronic mastitis (inflammation of the udder) and arthritis (joint inflammation) have become known.
The infection occurs with intensive contact from sheep to sheep or via milk (lactogenic) from the mother to the lamb. The exchange of blood or other body secretions is probably necessary, but it is also known that transmission by droplet infection (airborne) is possible. Transmission through cannulas is also discussed. Texel sheep and East Frisian dairy sheep are said to be particularly sensitive to MVV infections.
The incubation period is a maximum of about 5–6 years (according to other sources 2–3 years). It is therefore a so-called slow virus infection (English for "slow virus infection"). However, infected lambs can show their first symptoms as early as a month after birth. The MVV multiplies preferentially in macrophages , lymphocytes and monocytes . Penetration of the MVV causes the affected cells to proliferate . As with other lentiviruses, the infection is species-specific.
In Germany, Maedi-Visna is one of the notifiable animal diseases in sheep and goats .
Symptoms
Swelling of the lymph nodes and physical deterioration ( cachexia ) are observed in infected sheep .
The Maedi symptom complex leads to shortness of breath, coughing and pneumonia . Death occurs after 3 to 10 months.
In the Visna symptom complex, progressive demyelinating encephalomyelitis with paralysis (progressive inflammation of the brain and spinal cord that attacks the nerve envelope) occurs, which ends fatally after about a year.
After an MVV infection, other infectious diseases appear more frequently in the affected animals. This observation and the decrease in T4 lymphocytes are an indication of an MVV-related immunodeficiency .
therapy
There is no known causal therapy for MVV. Vaccinations are not yet possible. A serological detection of the MVV is possible by means of a complement fixation reaction.
Web links
- GoatConnection.com (English)
Individual evidence
- ↑ Annex to Section 1 of the Ordinance on Notifiable Animal Diseases (TKrMeldpflV) in the version published on February 11, 2011 ( Federal Law Gazette I p. 252 ), last amended by Article 381 of the Ordinance of August 31, 2015 ( Federal Law Gazette I p. 1474 )
