87. Ovine pulmonary adenomatosis.

Question 1

Occurrence and ethiology?

Answer 1

Ovine pulmonary adenomatosis/adenocarcinoma (Jaagsiekte = panting sickness)

• Retroviridae, Orthoretrovirinae, Betaretrovirus, Ovine pulmonary adenomatosis virus
• Susceptible: sheep (goat rare)

Occurrence:

• South Africa,
• widespread (exclude Australia, NZ, Iceland)

Etiology:

• 2 genotypes, no onc-gene (SLOW SPREAD),
• difficult to cultivate

Question 2

Epidemiology?

Answer 2

Epidemiology:

• introduction with asymptomatic animals
• infection with nasal discharge, tracheal discharge (contact, inhalation, PO), close contact is
• needed (trough), morbidity
• 5%, continousloss
• Whole flock will be infected, several animals asymptomatic

Question 3

Pathogenesis?

Answer 3

Pathogenesis: infection aerogenic or PO

• Replicate: epithelium of alveoli and bronchi
• Tumor transformation of epithelial cells: no onc-gene, envelope protein responsible
• Tumor cells replace normal lung tissue, fill alveoli
• Excess production of surfactant proteins by neoplastic cells
• Suffocation
• Slow spreading in the lungs, metastasis is rare (mediastinal LN)
• Shed in nasal discharge, No seroconversion ʹ no immune response!
• Chronic persistent infection

Question 4

Clinical signs?

Answer 4

Clinical signs:

• long incubation (months, year: 2-4): 2-4 yr old sheep
• No fever, slowly gets more severe, respiratory signs - respiratory distress, mouth breathing, tremor,
• respiratory sounds (rales), coughing is not typical, nasal discharge (low head, wheelbarrow test -
• clean, mucoid, up to 500 ml/day)
• Remains behind the flock
• Predisposes to complications (pasteurellosis)
• Good appetite, weight loss

Question 5

Pathology?

Answer 5

Pathology:

• lesions only in lungs, (LN), generally ventral
• Lungs: grey foci of different sizes, mucoid content in their cavity, increased weight of lungs with
• discharge, induration with CT, adhesion to the pleura
• LN: greyish foci
• Histology: adenocarcinoma
• Complication , more severe!

Question 6

Diagnosis?

Answer 6

Diagnosis:

• epidemiology, clinical signs, pathology, histology (histo will give definite diagnosis!)
• Detection of the virus: PCR (before clinical signs from lymphoid cells), ELISA
• Detection of antibodies: none ʹ no serological method!

Question 7

Prevention?

Answer 7

Prevention:

• removal of diseased animals cannot help/treat
• stamping out and replace herd