interstitial pneumonia caused by non onchogenic retrovirus of chronic nature

1. Diseases of lung
Ovine progressive
pneumonia (OPP)
(lunger disease)
Prof Dr Mohamed Ghanem
Prof of Veterinary Internal Medicine
Head Animal Medicine Department

2. Definition:
It is a lymphoproliferative pneumonia (chronic
type) caused by a slow viral infection of adult
sheep by a non-onchogenic retrovirus with signs
of dyspnoea, physical weakness and
emaciation.

3. Incidence and occurrence
1. It is fatal disease with high morbidity in
sheep.
2. Economic losses may be related to
1. Death and unthriftiness during the long course
of the disease and
2. The cost of control programs.
3. The proportion of infected sheep increases
with age (chronic nature).

4. Etiology
• The disease caused by a non-onchogenic
retrovirus of the subfamily lentiviridae.

5. Pathogenesis
Virus inhalation or
ingested with colostrum
(infected lymphocyte)
the bronchial and
mediastinal
lymph nodes,
spleen and kidneys
reticular cells and
B-lymphocytes
In lung
Proliferation
Thickening of
interstitial septum
Hyperplasia of the peribronchiolar and perivascular lymphoid tissues
reduce and obliterate alveoli
lower the efficiency of gaseous exchange and produce gradually fatal hypoxia
compress capillaries causes pulmonary arterial hypertension and right ventricular hypertrophy
inhaled virus invade

6. Clinical signs:
Incubation period 1-2 years:
• Animals are unable to walk and separate from flock.
• Animals are emaciated with progressive loss of body weight.
• Respiration accelerates. As the disease worsens, breathing
increases to 80-120/ min.
• Nostrils are dilated and head held high, mouth breathing
• Animals remain standing because recumbency forces the
diaphragm forward.
• Auscultation and percussion of the thorax reveal aeration in
dorsal parts of the lungs (loud bronchial sounds) and
consolidation in ventral parts.
• Body temperature is usually normal.
• Death results from hypoxia.

7. Sheep panting (oral breathing)

8. Diagnosis:
1. Clinical signs and lesions.
2. Laboratory confirmation by positive results from
1. complement –fixation tests,
2. agar gel immunodiffusion tests,
3. enzyme –linked immunosorbent assay,
4. virus isolation
3. Blood examination reveals:
1. hypogammaglobulinemia,
2. persisting leucocytosis.

9. OPP-affected lung showing
enlarged size and meaty texture

10. Consolidated lung

11. Histopathology
Normal lung tissue in sheep Lung with OPP in sheep – thickening of interstitial septum

12. Prevention, treatment and eradication:
Prevention is accomplished by:
• Avoiding exposure of healthy sheep to diseased
animals.
• Addition to the flock should be considered only
when the originating flock free of OPP.
• OPP free lambs can be obtained by removing them
from their dam at birth prior to receiving colostrum
from the infected dam and rearing in a clean
atmosphere away from infected sheep.

13. Eradication
1. Animals from infected flocks can not be
sold live, to restrict spread.
2. Testing of antibodies every 6 months C.F.T
and ELISA and culling of all reactors.

14. Questions on
OPP