Histopathological, serological, molecular and electron microscopy detection of Maedi-Visna infection in sheep population in the West of Iran

Document Type : Full paper (Original article)


1 Ph.D. Student in Pathology, Department of Pathobiology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran

2 Department of Pathobiology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran


Background: Maedi-Visna (MV) is a progressive lymphoproliferative viral disease that affects multiple organs of small ruminants, including sheep and goats. The disease occurs primarily in the lung tissue and causes interstitial pneumonia. Aims: The aim of present study was to investigate the prevalence of ovine MV infection in Iranian sheep population through macroscopic, histopathological, serological, and molecular assays, as well as transmission electron microscopy (TEM). Methods: Lung and blood samples of one-hundred female sheep (≤ 2 years old) referred to the Kermanshah slaughterhouse with respiratory symptoms were collected for histopathological and molecular evaluations. Corresponding serum samples were also collected for serological examination. Results: Histopathological study showed the Maedi-like pulmonary lesions in 85% of the affected lungs, which included the interstitial pneumonia, smooth muscle hypertrophy of alveolar septa and around the blood vessels, interstitial lymphoplasmacytic infiltration and lymphofollicular hyperplasia. Specific antibodies against MV virus were detected in 7% of serum samples. Long terminal repeat (LTR) region of MV provirus was amplified in three (3%) DNA samples, extracted from the suspected lungs. Sequencing analysis of polymerase chain reaction (PCR)-positive samples confirmed the presence of MV provirus in the genome. No amplification was observed, neither in the DNA samples extracted from the blood samples of suspected sheep nor the control group. Transmission electron microscopy also confirmed the presence of MV virions inside the cytoplasmic membrane of MV-infected macrophages. Conclusion: Although histopathology can provide a preliminary estimation of Maedi in populations, definitive diagnosis of the disease needs to be approved by more sensitive techniques such as serological examinations and molecular analysis.


Asadpour, R; Paktinat, S; Ghassemi, F and Jafari, R (2014). Study on correlation of Maedi-Visna virus (MVV) with ovine subclinical mastitis in Iran. Indian J. Microbiol., 54: 218-222.
Azizi, S; Tajbakhsh, E; Fathi, F; Oryan, A; Momtaz, H and Goodarzi, M (2012). Maedi in slaughtered sheep: a pathology and polymerase chain reaction study in southwestern Iran. Trop. Anim. Health Prod., 44: 113-118.
Beigi Borujeni, N; Pourmahdi Borujeni, M; Hajikolaei, MR and Saify Abad Shapouri, MR (2015). Seroprevalence of Maedi-Visna in sheep in Khuzestan province. Iran. Vet. J., 11: 34-43.
Benavides, J; Fuertes, M; Garcia-Pariente, C; Otaola, J; Delgado, L; Giraldez, J; Marín, JFG; Ferreras, MC and Pérez, V (2013). Impact of Maedi-Visna in intensively managed dairy sheep. Vet. J., 197: 607-612.
Brinkhof, JM; Houwers, DJ; Moll, L; Dercksen, D and van Maanen, C (2010a). Diagnostic performance of ELISA and PCR in identifying SRLV-infected sheep and goats using serum, plasma and milk samples and in early detection of infection in dairy flocks through bulk milk testing. Vet. Microbiol., 142: 193-198.
Brinkhof, JM; Moll, L; van Maanen, C and Houwers, DJ (2010b). Use of serology and polymerase chain reaction for the rapid eradication of small ruminant lentivirus infections from a sheep flock: a case report. Res. Vet. Sci., 88: 41-43.
Brinkhof, JM; van Maanen, C; Wigger, R; Peterson, K and Houwers, DJ (2008). Specific detection of small ruminant lentiviral nucleic acid sequences located in the proviral long terminal repeat and leader-gag regions using real-time polymerase chain reaction. J. Virol. Methods. 147: 338-344.
Carrozza, ML; Mazzeim, M; Bandecchi, P; Fraisier, C; Perez, M; Suzan-Monti, M; de Andrés, D; Amorena, B; Rosati, S; Andrésdottir, V and Lujan, L (2010). Development and comparison of strain specific gag and pol real-time PCR assays for the detection of Maedi-Visna virus. J. Virol. Methods. 165: 161-167.
Caswell, JL and Williams, KJ (2016). Respiratory system. In: Maxie, MG (Ed.), Jubb, Kennedy and Palmer’s pathology of domestic animals. (6th Edn.), Vol. 2, Philadelphia, Elsevier. PP: 558-560.
Crespo, H; Bertolotti, L; Proffiti, M; Cascio, P; Cerruti, F; Acutis, PL; De Andrés, D; Reina, R and Rosati, S (2016). Low proviral small ruminant lentivirus load as biomarker of natural restriction in goats. Vet. Microbiol., 192: 152-162.
De Andres, D; Klein, D; Watt, NJ; Berriatua, E; Torsteinsdottir, S; Blacklaws, BA and Harkiss, GD
(2005). Diagnostic tests for small ruminant lentiviruses. Vet. Microbiol., 107: 49-62.
De Souza, TS; Pinheiro, RR; Costa, JN; Lima, CC; Andrioli, A; Azevedo, DA; dos Santos, VW; Araújo, JF; Sousa, ALMD; Pinheiro, DN and Fernandes, F (2015). Interspecific transmission of small ruminant lentiviruses from goats to sheep. Braz. J. Microbiol., 46: 867-874.
Extramiana, AB; Gonzalez, L; Cortabarria, N; Garcia, M and Juste, RA (2002). Evaluation of a PCR technique for the detection of Maedi-Visna proviral DNA in blood, milk and tissue samples of naturally infected sheep. Small Rum. Res., 44: 109-118.
Fournier, D; Campbell, JR and Middleton, DM (2006). Prevalence of Maedi-Visna infection in culled ewes in Alberta. Can. Vet. J., 47: 460-466.
Herrmann-Hoesing, LM (2010). Diagnostic assays used to control small ruminant lentiviruses. J. Vet. Diagn. Invest., 22: 843-855.
Lago, N; Lopez, C; Panadero, R; Cienfuegos, S; Pato, J; Prieto, A; Diaz, P; Mourazos, N and Fernandez, G (2012). Seroprevalence and risk factors associated with Maedi-Visna virus in semi-intensive lamb-producing flocks in northwestern Spain. Prev. Vet. Med., 103: 163-169.
Leginagoikoa, I; Minguijon, E; Juste, RA; Barandika, J; Amorena, B; de Andres, D; Badiola, JJ; Luján, L and Berriatua, E (2010). Effects of housing on the incidence of Visna/Maedi virus infection in sheep flocks. Res. Vet. Sci., 88: 415-421.
Minardi da Cruz, JC; Singh, DK; Lamara, A and Chebloune, Y (2013). Small ruminant lentiviruses (SRLVs) break the species barrier to acquire new host range. Viruses. 5: 1867-1884.
Minguijon, E; Reina, R; Pérez, M; Polledo, L; Villoria, M; Ramírez, H; Leginagoikoa, I; Badiola, JJ; García-Marín, JF; De Andrés, D and Luján, L (2015). Small ruminant lentivirus infections and diseases. Vet. Microbiol., 181: 75-89.
Muz, D; Oğuzoğlu, TC; Rosati, S; Reina, R; Bertolotti, L and Burgu, I (2013). First molecular characterization of Visna/Maedi viruses from naturally infected sheep in Turkey. Arch. Virol., 158: 559-570.
Norouzi, B; Taghavi Razavizadeh, A; Azizzadeh, M; Mayameei, A and Najar Nezhad Mashhadi, V (2015).
Serological study of small ruminant lentiviruses in sheep population of Khorasan-e-Razavi province in Iran. Vet. Res. Forum., 6: 245-249.
Nowicka, D; Czopowicz, M; Bagnicka, E; Rzewuska, M; Strzałkowska, N and Kaba, J (2015). Influence of small ruminant lentivirus infection on cheese yield in goats. J. Dairy Res., 82: 102-106.
Oguma, K; Tanaka, C; Harasawa, R; Kimura, A; Sasaki, J; Goryo, M and Sentsui, H (2014). Isolation of Maedi/ Visna virus from a sheep in Japan. J. Vet. Med. Sci., 76: 211-218.
Pepin, M; Vitu, C; Russo, P; Mornex, JF and Peterhans, E (1998). Maedi-Visna virus infection in sheep: a review. Vet. Res., 29: 341-367.
Peterhans, E; Greenland, T; Badiola, J; Harkiss, G; Bertoni, G; Amorena, B; Eliaszewicz, M; Juste, RA; Kraßnig, R; Lafont, JP and Lenihan, P (2004). Routes of transmission and consequences of small ruminant lentiviruses (SRLVs) infection and eradication schemes. Vet. Res., 35: 257-274.
Preziuso, S; Magi, GE; Mari, S and Renzoni, G (2013). Detection of Visna Maedi virus in mesenteric lymph nodes and in other lymphoid tissues of sheep three years after respiratory infection. Vet. Med., 58: 359-363.
Sakhaee, E and Khalili, M (2010). Serological study of Maedi-Visna virus among sheep flocks in Kerman province of Iran. Iran. J. Virol., 4: 29-33.
Sasani, F; Javanbakht, J; Hemmatzadeh, F; Rajabi-Moghadam, M and Aghamohammad Hassan, M (2013). Evaluation of histopathological on Maedi disease with serological confirmation in North-East of Iran. Res. J. Infect. Dis., https://doi.org/ 10.7243/2052-5958-1-5.
Sayari, M and Lotfi, M (2001). Serological and pathological study of Maedi in sheep’s lung in Ahvaz. J. Vet. Res., 53: 91-94.
Villoria, M; Leginagoikoa, I; Lujan, L; Perez, M; Salazar, E; Berriatua, E; Juste, RA and Minguijón, E (2013). Detection of small ruminant lentivirus in environmental samples of air and water. Small Rum. Res., 110: 155-160.
Zhang, K; He, J; Liu, Y; Shang, Y and Liu, X (2013). A seroprevalence survey of Maedi-Visna among twenty-four ovine floks from twelve regions of China. J. Integr. Agric., 12: 2321-2323.