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Updated: May 6, 2026
Propagating and Detecting an Infectious Molecular Clone of Maedi-visna Virus that Expresses Green Fluorescent Protein
Published on: October 9, 2011
Isolation of maedi/visna virus from a sheep in Japan
Keisuke Oguma1, Chiaki Tanaka, Ryo Harasawa
1Laboratory of Veterinary Epizootiology, Department of Veterinary Medicine, Nihon University, 1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan.
Abstract:
Maedi/visna (MV) is a lentiviral disease of sheep caused by the maedi/visna virus (MVV). Although MV is prevalent in many countries, it had not been reported in Japan. In 2011, however, three sheep in northern Japan were reported to be seropositive against the MVV antigen, indicating a persistent MVV infection. In the present study, we isolated MVV from one sheep to confirm MVV infection and conducted genomic classification of the virus. The co-culture of leukocytes from a seropositive sheep with fetal goat lung cells resulted in the formation of syncytial cells and the amplification of a long terminal repeat sequence of MVV by polymerase chain reaction. The isolate was confirmed as being MVV, rather than the caprine arthritis-encephalitis virus based on phylogenetic analysis of the gag gene sequence. Although the sheep was asymptomatic, nonpurulent meningitis and demyelination were found in the spinal cord. These were considered to be early lesions associated with pathogenic MVV infection. Therefore, the present study demonstrated that MVV is distributed in Japan.
Insights
Maedi/visna virus (MVV) infection was confirmed in sheep in Japan, a country where it was previously unreported. Early neurological lesions were identified, indicating the pathogen
Area of Science:
- Veterinary Virology
- Sheep Pathology
- Lentivirus Research
Background:
- Maedi/visna (MV) is a lentiviral disease affecting sheep, caused by the maedi/visna virus (MVV).
- MVV is globally prevalent but had not been previously reported in Japan.
- Serological evidence of MVV infection emerged in Japanese sheep in 2011.
Purpose of the Study:
- To confirm the presence of maedi/visna virus (MVV) in Japan.
- To isolate and genetically classify an MVV strain from an infected sheep.
- To investigate early pathological changes associated with MVV infection in asymptomatic sheep.
Main Methods:
- Leukocyte co-culture from a seropositive sheep with fetal goat lung cells.
- Polymerase chain reaction (PCR) amplification of the MVV long terminal repeat (LTR) sequence.
- Phylogenetic analysis of the gag gene sequence for viral classification.
Main Results:
- Successful isolation and confirmation of MVV from a Japanese sheep.
- Phylogenetic analysis confirmed the isolate as MVV, distinct from caprine arthritis-encephalitis virus.
- Histopathological examination revealed nonpurulent meningitis and demyelination in the spinal cord of an asymptomatic sheep.
Conclusions:
- The study confirms the circulation of maedi/visna virus (MVV) in Japan.
- Early neurological lesions suggest pathogenic potential even in asymptomatic carriers.
- This finding highlights the need for surveillance and understanding of MVV epidemiology in Japan.
