obsolete ovine progressive interstitial pneumonia

Ovine Progressive Pneumonia (OPP): An Obsolete Disease

Ovine progressive pneumonia, also known as maedi-visna, is a chronic and debilitating disease that affects sheep. The disease was once prevalent in many parts of the world, particularly in Europe and North America.

Characteristics of OPP

• Multi-systemic disease: OPP affects multiple systems in the body, including the lungs, nervous system, joints, and mammary glands.
• Chronic lymphocytic pneumonitis: The disease is characterized by chronic inflammation of the lungs, leading to interstitial pneumonia.
• Encephalitis, arthritis, mastitis, and vasculitis: OPP can also cause encephalitis (inflammation of the brain), arthritis (joint inflammation), mastitis (inflammation of the mammary glands), and vasculitis (inflammation of the blood vessels).
• Progressive wasting and dyspnea: As the disease progresses, sheep may experience progressive wasting, difficulty breathing (dyspnea), lameness, and induration (hardening) of the skin.

Transmission and Causes

• Lentiviruses: OPP is caused by lentiviruses, a type of retrovirus that belongs to the Lentiviridae subfamily.
• Transmission through milk and colostrum: The disease can be transmitted through the consumption of infected milk or colostrum from an infected ewe.

Lesions in Sheep with OPP

• Mottled grayish-pink lungs: The lungs of sheep affected by OPP are often mottled grayish-pink, firm, and large (two to three times normal weight).
• Chronic diffuse interstitial pneumonitis: The disease is characterized by chronic inflammation of the lungs, leading to extensive hyperplasia of lymphoid cells around airways and blood vessels.

References

• [4] SF Peek et al. (2018) - Inspiratory dyspnea in sheep with upper airway obstructions.
• [6] ML Delano et al. (2002) - Serological evidence suggests that diffuse chronic mastitis is caused by the retrovirus that causes ovine progressive pneumonia (OPP or maedi/visna virus).
• [12] Ovine progressive pneumonia (OPP) is a multi-systemic disease of sheep caused by a non-oncogenic exogenous retrovirus belonging to the Lentiviridae subfamily.
• [13] Ovine progressive pneumonia (OPP), or maedi-visna, is a chronic disease of sheep due to lentiviruses (enveloped, single-stranded RNA viruses in the family Retroviridae).
• [15] Lesions in sheep with ovine progressive pneumonia are described.

Diagnostic Tests for Ovine Progressive Pneumonia (OPP)

Ovine progressive pneumonia (OPP) is a viral disease affecting sheep, causing respiratory and other systemic problems. Diagnosing OPP can be challenging, but various tests can help confirm the presence of the virus.

• Clinical Signs: Veterinarians diagnose OPP based on clinical signs such as coughing, difficulty breathing, and weight loss [1]. However, relying solely on clinical signs can lead to misdiagnosis.
• Endoscopic Examination: An endoscopic examination of the nasal and nasopharyngeal cavity can help identify lesions associated with OPP [1].
• Cytology: Cytological examination of a cotton swab soaked in blood from the affected animal is considered an ideal sample for laboratory confirmation [2].
• Radiography: Radiographic imaging can assist in differentiating between various respiratory conditions, including OPP [3].
• PCR and Virus Isolation: Polymerase chain reaction (PCR) and virus isolation are sensitive and specific techniques to detect the OPP virus. However, these methods are more expensive and time-consuming than other diagnostic tests [10].

Other Diagnostic Tests

In addition to the above-mentioned tests, fetal and maternal serology, as well as diagnostic tests such as the microscopic agglutination test, can be used to diagnose OPP [7]. It is essential to note that these tests may not always provide a definitive diagnosis.

References:

[1] SF Peek (2018) - Diagnosis based on clinical signs alone is difficult. Laboratory confirmation should be attempted...

[2] SF Peek (2018) - The ideal sample is a cotton swab soaked in the blood and ...

[3] SF Peek (2018) - Radiography can assist in the recognition and differentiation of atelectasis and consolidation, interstitial and exudative pneumonias...

[7] C Cousens (2024) - Fetal and maternal serology, and diagnostic tests such as the microscopic agglutination test ...

[10] Apr 6, 2017 - PCR and virus isolation are sensitive and specific techniques to detect virus. However, both are more expensive and time consuming than ...

Based on the provided context, it appears that there are limited treatment options available for ovine progressive interstitial pneumonia (OPP). However, some medications have been used to manage symptoms and slow disease progression.

• Anti-inflammatory drugs: Palliative treatment with anti-inflammatory drugs may be considered in certain cases of OPP. These medications can help alleviate symptoms such as inflammation and pain.
• Enrofloxacin with bromhexine: A combination of enrofloxacin (an antibiotic) and bromhexine (a mucolytic agent) has been used to treat OPP in some cases. This treatment was administered parenterally at a dose of 5.0 mg/kg per day for five days.
• No specific antiviral treatment: Unfortunately, there is no specific antiviral treatment available for OPP. The disease is caused by a lentivirus, and current treatments focus on managing symptoms rather than targeting the virus directly.

It's essential to note that these treatment options may not be effective in all cases of OPP, and the disease can have a significant impact on sheep health and productivity.

References:

• [10] mentions palliative treatment with antiinflammatory drugs.
• [12] describes enrofloxacin with bromhexine treatment for OPP.
• [13] does not provide specific treatment information but mentions that there is no specific antiviral treatment available.