Jaagsiekte

Jaagsiekte is a progressive, often fatal, contagious respiratory disease that affects sheep and goats. The name is derived from the Afrikaans word "jaagsiekte," meaning "chasing sickness," referring to the characteristic labored breathing and panting that can appear after exertion.

The disease is caused by a retrovirus, ovine pulmonary adenocarcinoma virus (OPAV), which infects cells in the lungs, causing them to proliferate abnormally and form tumors. These tumors obstruct the airways, leading to severe respiratory distress. Transmission typically occurs through inhalation of infectious particles shed by infected animals, often in close-contact environments like sheep pens.

Clinical signs include increased respiratory rate, shallow breathing, coughing, nasal discharge, and weight loss. Animals may appear to "chase" their breath, especially when stressed or exercised. The incubation period can be long, and the disease progresses slowly over months or even years before clinical signs become apparent.

Diagnosis involves a combination of clinical signs, gross and microscopic examination of lung tissue, and serological tests to detect antibodies against OPAV. There is no effective treatment for jaagsiekte, and control relies on biosecurity measures, early detection, and removal of infected animals from the flock. Prevention strategies include maintaining good ventilation, avoiding overcrowding, and implementing quarantine for new animals.