Pulmonary adenomatosis and maedi-visna in Ethiopian central highland sheep: a microscopic study

Aim:The small ruminant lentiviruses are known to cause maedi-visna (MV) and caprine arthritis - encephalitis in sheep and goats, typically affecting joints, udder, lungs, and the central nervous system. The diagnosis usually involves serology, clinical signs, immunohistochemistry, and polymerase chain reaction (PCR). In the present study, the histopathologically positive pneumonia cases of MV were confirmed by PCR in lung tissue probably for the first time in India.Materials and Methods:A total of 888 lungs of adult sheep, aged between 2 and 5 years, were screened during slaughter, of which 121 were found to have pneumonic lesions. The tissues from each pneumonic lung including associated lymph nodes were collected in 10% neutral buffered formalin for histopathology. The frozen tissues of the same were also collected and stored at −20°C for PCR confirmation.Results:Three of 121 cases of pneumonic lungs of sheep revealed gross and histopathological lesions suggestive of maedi or ovine progressive pneumonia infection. These 3 cases were further confirmed by PCR technique that amplified 291-base pair DNA in the long terminal repeat sequence of MV provirus.Conclusion:This study suggests the low occurrence of MV virus (MVV) infection in India in naturally affected sheep based on pathomorphological lesions and using the molecular tool of PCR detection of the virus in tissues. Further, a combination of pathomorphology or/and PCR testing might be optimal for detecting the animals infected with MVV.

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“…The histopathological findings in the present study are in concurrence with earlier reports [ 11 , 27 , 29 , 34 ]. Sasani et al .…”

Section: Discussionsupporting

confidence: 93%

Pathology and polymerase chain reaction detection of ovine progressive pneumonia (maedi) cases in slaughtered sheep in India

et al. 2017

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“…The histopathologic findings of the present study are comparable to those reported earlier (Angelopoulou et al 2006;Christodoulopoulos 2006;Woldemeskel and Tibbo 2010). Comparison of histopathological findings and PCR results showed that LTR-PCR is highly specific and sensitive in detecting the MVV provirus in the lung samples of sheep.…”

Section: Discussionsupporting

confidence: 89%

Maedi in slaughtered sheep: A pathology and polymerase chain reaction study in southwestern Iran

Azizi

Tajbakhsh

Fathi

et al. 2011

Trop Anim Health Prod

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Maedi-visna (MV) is an important slow viral disease of sheep leading to a progressive lymphoproliferative disease. It affects multiple organs primarily the lungs, where it causes interstitial pneumonia (maedi). In this study, the lungs of 1,000 sheep carcasses were grossly inspected and those suspected to have maedi were studied at histopathological and molecular levels. A polymerase chain reaction (PCR) technique that amplified a 291-base pair DNA in the long terminal repeat (LTR) sequence of MV provirus was conducted on all the 50 suspected lungs together with 10 normal appearing lungs as controls. Amplicons of the expected size were detected in 11 (n=11/50) suspected sheep, and one of the 10 control sheep. Histopathologic study of the pulmonary lesions of all 11 (n=11/11) positive sheep showed MV lesions, including hyperplasia of the perivascular and peribronchiolar lymphoid cells, interstitial lymphoplasmacytic infiltration and smooth muscle hyperplasia and the histopathologic findings were correlated with PCR results. In contrast, the tissue sections of control animals were almost normal at histopathological level; however, PCR technique demonstrated that one of them was affected by maedi. This study showed that the LTR-PCR had high specificity and sensitivity in diagnosis of this viral infection. This study is the first to evaluate the prevalence of MV virus infection in sheep in Iran.

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“…Ovine pulmonary adenocarcinoma (OPA), also known as Jaagsiekte disease, was the least form of pneumonia that was detected in only five sheep. The gross and histopathologic features observed were classic and similar to the previous reports from Ethiopia and elsewhere [36, 55, 58, 72]. Concurrent infection of OPA with suppurative bronchopneumonia and ovine progressive pneumonia was also reported earlier by Woldemeskel and Tibbo [55].…”

Section: Discussionsupporting

confidence: 87%

Prevalence of Pneumonia in Sheep and Goats Slaughtered at Elfora Bishoftu Export Abattoir, Ethiopia: A Pathological Investigation

Mekibib

Mikir

Fekadu

et al. 2019

Journal of Veterinary Medicine

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Accurate clinical diagnosis of pneumonia, the leading cause of mortality in small ruminants, is difficult and usually requires postmortem examination of the lungs. An active abattoir survey was conducted between November 2017 and April 2018 to estimate the prevalence and characterize the gross and histopathological lesions of pneumonic lungs in 864 clinically healthy young small ruminants (490 sheep and 374 goats aged 1.5 to 3 years) raised for meat in different parts of the country and slaughtered at Elfora Bishoftu export abattoir, Ethiopia. Out of the total lungs examined grossly, pneumonic lesions were found in 158 (18.29%) lungs. On histopathological examination of the lungs with gross pneumonic lesion, however, typical pneumonic lesions were diagnosed in 148 (17.13%) lungs only. No significant (p>0.05) difference was noted in the prevalence of pneumonia between sheep (17.14%) and goats (17.11%) in histopathological examination. Based on the predominant histopathological findings, the pneumonic lesions were characterized as interstitial pneumonia (41.9%), acute suppurative bronchopneumonia (25.7%), acute fibrinous bronchopneumonia (24.3%), chronic bronchopneumonia (6.1%), aspiration pneumonia (4.7%), bronchointerstitial pneumonia (3.4%), and ovine pulmonary adenomatosis (3.4%). The study further showed the spread of ovine pulmonary adenomatosis and ovine progressive pneumonia (Maedi) from the central highlands to areas that were previously free from these diseases. Due to its better diagnostic capacity, histopathology should be employed routinely as an ancillary test in the major abattoirs and regional veterinary laboratories to generate additional epidemiological data for a better disease control and prevention measures. Further studies are also recommended to identify the etiological agents of pneumonia in sheep and goats and thereby to formulate feasible and cost-effective interventions.

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Pulmonary adenomatosis and maedi-visna in Ethiopian central highland sheep: a microscopic study

Cited by 9 publications

References 6 publications

Pathology and polymerase chain reaction detection of ovine progressive pneumonia (maedi) cases in slaughtered sheep in India

Pathology and polymerase chain reaction detection of ovine progressive pneumonia (maedi) cases in slaughtered sheep in India

Maedi in slaughtered sheep: A pathology and polymerase chain reaction study in southwestern Iran

Prevalence of Pneumonia in Sheep and Goats Slaughtered at Elfora Bishoftu Export Abattoir, Ethiopia: A Pathological Investigation

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