Jaagsiekte, also known as ovine pulmonary adenocarcinoma, is a transmissible lung cancer in sheep caused by the Jaagsiekte sheep retrovirus (JSRV). It presents as multiple firm tumors in the lungs that can be seen running from the nose. Microscopically, the tumors are well-differentiated bronchioloalveolar carcinomas that fill the alveoli. The virus infects type II pneumocytes and Clara cells in the lungs. While diagnosis relies on pathology, PCR and detecting the virus in tissues of young lambs offers potential for earlier detection.

1. Jaagsiekte
(zag-zi-ekte)
Ovine pulmonary Adenocarcinoma
Presented By: Sulove Koirala

2. Introduction
• A transmissible, retrovirus-induced neoplasia of sheep lungs
• Also called Driving Sickness
• Causative Agent: Jaagsiekte Sheep Retrovirus (JSRV)
• Spread by droplet infection from respiratory secretions.
• Rare in younger sheep, and is most common at 3-4 years of age

3. Clinical Signs
• The incubation period in natural cases is 1-3 years
• Sharp sounds can be heard from the affected area
• Clinical signs are not noticeable until a significant
proportion of the lung is affected by the tumor
• Unique feature: Overproduction of fluid in the lung
that can be seen running from the nose when the
animal lowers its head

4. Gross Lesions
• Multiple, firm, raised, gray or white,
moist masses in the cranial and
middle lung lobes
• Lungs are heavy, up to three times
their normal weight
• Airways are filled with foamy
secretion from the neoplastic cells.

5. Microscopic Lesions
• Well-differentiated bronchioloalveolar carcinoma.
• Within the neoplastic masses, the alveolar architecture remains, but alveoli are lined
by cuboidal or columnar neoplastic epithelial cells.
• Proliferation of neoplastic cells results in papillary or acinar structures filling alveoli
and obscuring their outline.
• Alveoli adjacent to the tumors are atelectatic and contain many macrophages, and
interstitial fibrosis may be present in advanced cases.

6. Image Source:
Jubb, Kennedy & Plamer
Pathology of Domestic Animals,
2007
(p 622)

7. Pathophysiology
Virus Replicates in Type II pneumocyte in
alveolus
Type II pneumocyte and Clara cells of
bronchiole are transformed
Produces intra-alveolar and intra-
bronchiole polypoid ingrowth

8. Contd…
The adenomatous ingrowths of
alveolar epithelium encroach
gradually upon alveolar space
Anoxia

9. Diagnosis
• At present, diagnosis of OPA relies on clinical and pathological
investigations
• Wheel Barrow Test: One lifts the hind legs of the animal above the head
to observe lung exudate flow out of its nose and mouth
• Polymerase chain reaction (PCR) offers hope for ante-mortem diagnosis of
OPA as a flock test.
• Presence must be confirmed, at least once, by histopathological
examination of affected lung tissue.

10. Recent Advances
• Results suggest that JSRV-infected cells may be present in the
bone marrow of symptomless animals
• Jaagsiekte Sheep Retrovirus-Positive Cells are found in tissues of
very young lambs fed naturally with colostrum from infected
ewes.

11. References
Borobia, M. D. (2012). Jaagsiekte Sheep Retrovirus-Positive Cells are Found in Tissues of Very
Young Lambs Fed Naturally with Colostrum from Infected Ewes. Journal of Comparative Pathology, 146(1).
Borobia, M. D. (2014). Cells infected with Jaagsiekte sheep retrovirus are detected in the bone marrow
of asymptomatic sheep. Canadian Journal of Veterinary Research, 78-80.
Jubb, Kennedy, & Palmer. (2007). Pathology of Domestic Animals. In Jubb, Kennedy, & Palmer,
Pathology of Domestic Animals (pp. 621-622). Saunders Ltd.
Vegad, J. L. (2012). Textbook of veterinary special pathology. In J. L. Vegad, Textbook of
veterinary special pathology (pp. 100-101). International Book Distributing Company.
Zachary, J. F. (2012). Pathologic Basis of Veterinary Diseases. In F. J. Zachary, Pathologic Basis of
Veterinary Diseases (pp. 532-533). Elsevier Health Sciences.
Image Source
http://www.cfsph.iastate.edu/DiseaseInfo/ImageDB/OPA/OPA_003.jpg
http://veterinaryrecord.bmj.com/content/168/15/393.2/F1.large.jpg

12. Questions???