Equine multinodular pulmonary fibrosis

Equine multinodular pulmonary fibrosis is a chronic lung disease of horses. There is evidence that the disease is caused by infection with a gammaherpesvirus, equine herpesvirus 5. The disease affects usually adult horses reducing the ability to exercise as a result of the formation of nodular lesions in the lungs.[1]

Equine multinodular pulmonary fibrosis
SpecialtyVeterinary medicine

Signs and symptoms

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Signs of equine multinodular pulmonary fibrosis are mainly weight loss, fever, respiratory distress and depression. [2][3] Unwillingness to move, mild cough and intermittent tachypnea have been reported.[4] When the disease progresses, the general condition of the horse usually deteriorates, showing possible signs as severe dyspnea, hypoxemia or nasal discharge. [4][3]

Diagnosis

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Generally EMPF has been categorized as an uncommon disease in horses with idiopathic in origin. Comparing to other interstitial fibrosing lung diseases in horses, the lesions in EMPF differ remarkably due to their nodular pattern.[2] In histologic examinations, a sharp border may be discerned between the fibrotic and intact lung tissue.[5] Integrative fact among horses with EMPF has been frequently established to be an infection of EHV-5. Diagnosis is based on the PCR results and pathomorphological findings from lungs.[2] The disease has been reported as part of the granumalomatous process in an apparent silicate pneumoconiosis. [5] Among horses with diagnosed EMPF, thoracic radiography have shown several changes. Generalized mixed interstitial and nodular pattern in the lung parenchyma, [4] large radiodense opacity in the caudodorsal area of the lung [2] and thickened peribronchial walls.[3] Thoracic ultrasonography have demonstrated a bilaterally generalized pleural roughening, several comet tails and multiple, hyperechogenic scattered areas.[3]

Pathology findings

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Based on a study of 5 horses by T. POTH, G. NIEDERMAIER and W. HERMANNS (2009) as well as on a study of 24 horses investigated by WILLIAMS et al. (2007), there are significant pathomorphological findings in lungs with equine multinodular pulmonary fibrosis. In gross findings can be noticed pulmonary induration in all lung lobes as well as lesions restricted to the lungs and the bronchiolar lymph nodes. The distribution between two patterns can be seen as a large, whitish until tan and firm nodules of fibrosis. There are noticed histological findings, such as fibrosis and inflammation in different stages and degrees. In alveolies accumulation of neutrophils can be identified, and enlarged, vacuolated macrophages with several multinucleated giant cells. In addition hypertrophy of type II pneumocytes, formation on abnormal cystic airspaces and viral eosinophilic intranuclear inclusion bodies in intraluminal macrophages.[2]

Treatment and prognosis

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Different treatments have been experimented with horses diagnosed EMPF, but the prognosis of EMPF is tentative to unfavourable.[2]

References

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  1. ^ Williams KJ (March 2014). "Gammaherpesviruses and pulmonary fibrosis: evidence from humans, horses, and rodents". Veterinary Pathology. 51 (2): 372–84. doi:10.1177/0300985814521838. PMID 24569614. S2CID 22704874.
  2. ^ a b c d e f Poth T, Niedermaier G, Hermanns W (January 2009). "Equine multinodular pulmonary fibrosis in association with an EHV-5 infection in 5 horses". Wiener Tierärztliche Monatsschrift. 96 (7/8): 203–8. S2CID 2795321.
  3. ^ a b c d Marenzoni ML, Passamonti F, Lepri E, Cercone M, Capomaccio S, Cappelli K, et al. (July 2011). "Quantification of Equid herpesvirus 5 DNA in clinical and necropsy specimens collected from a horse with equine multinodular pulmonary fibrosis". Journal of Veterinary Diagnostic Investigation. 23 (4): 802–6. doi:10.1177/1040638711407890. PMID 21908328.
  4. ^ a b c Back H, Kendall A, Grandón R, Ullman K, Treiberg-Berndtsson L, Ståhl K, Pringle J (September 2012). "Equine multinodular pulmonary fibrosis in association with asinine herpesvirus type 5 and equine herpesvirus type 5: a case report". Acta Veterinaria Scandinavica. 54 (1): 57. doi:10.1186/1751-0147-54-57. PMC 3511884. PMID 23009194.
  5. ^ a b Williams KJ, Maes R, Del Piero F, Lim A, Wise A, Bolin DC, et al. (November 2007). "Equine multinodular pulmonary fibrosis: a newly recognized herpesvirus-associated fibrotic lung disease". Veterinary Pathology. 44 (6): 849–62. doi:10.1354/vp.44-6-849. PMID 18039898.
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