Presence of Maedi Visna Virus (MVV)‐Proviral DNA in the Genital Tissues of Naturally Infected Ewes

Abstract

Maedi Visna virus (MVV) causes progressive degenerative inflammatory disease in multiple organs including the lungs (pneumonia, 'maedi'), mammary gland, joints and nervous system (meningoencephalomyelitis, 'visna') in sheep. Maedi Visna Virus has been detected in macrophages of several tissues and epithelial cells in vivo: bone marrow, cells of the central nervous system, lung and bronchial tissues, milk epithelial cells recovered from milk samples and epithelial cells of mammary tissue. However, the presence of MVV in the genital tracts of naturally infected ewes has not previously been studied. The aim of this study was to use nested-PCR, targeting the gag gene, to determine whether genital tissues (ovaries, oviducts and uterus) from 83 ewes originating from various breeding herds in the South-East of France were positive for MVV-proviral DNA. Peripheral blood mononuclear cells (PBMC) tested positive for MVV-proviral DNA, using nested-PCR analysis, in 57.8% of ewes (48/83). The provirus was also identified in 47% (78/166) of the ovaries, 38.6% (64/166) of the oviducts and 45.8% (38/83) of the uteri sampled. These findings clearly demonstrate, for the first time, that tissue samples from the genital tract of ewes (ovary, oviduct and uterus) can be infected with MVV. This suggests that there is a risk of vertical and/or horizontal transmission of MVV during embryo transfer from embryos produced in vivo or in vitro.

Genome-Wide Association Identifies Multiple Genomic Regions Associated with Susceptibility to and Control of Ovine Lentivirus

“…Both DPPA2 and the nearby DPPA4 play essential roles in lung development and formation [28], [29], suggesting differential lung development in sheep may play a role in OvLV susceptibility. However, OvLV has been found in semen and in the female reproductive tract of sheep [30], [31], and the possibility of sexual transmission and/or paternal transmission of the virus are important unanswered questions. If OvLV is sexually or paternally transmitted, germline expressed DPPA2 may play a role in some aspect of transmission.…”

Haematological parameters in blood of maedi-visna virus-infected and uninfected sheep

“…Lentivirus diseases are commonly seen worldwide (Benavides et al, 2009). Caprine arthritis encephalitis virus (CAEV) is closely related to MVV (Cortez-Romero et al, 2010). MVV was the first lentivirus to be isolated and characterized in Iceland in 1957 (Sigurdsson et al, 1953).…”

Estudio de la patogenia el Maedi-Visna ovino y su aplicación en el diagnóstico y control de la enfermedad = Study of ovine Maedi-Visna pathogenia and its application in diagnostic and illness control

“…También se ha propuesto la vía vertical como posible vía de contagio de los LVPR, aunque actualmente se considera una vía de escasa importancia epidemiológica (Blacklaws et al, 2004;Peterson et al, 2008;Broughton-Neiswanger et al, 2010;Romero et al, 2010;Cortez-Romero et al, 2011;Cortez-Romero et al, 2013). Se ha demostrado la presencia de ADN proviral de LVPR en el aparato genial de hembras infectadas, lo que explica la posible transmisión de la madre al embrión o feto in utero (transmisión vertical).…”

“…Así mismo, se han descrito un cierto número de casos de infección in utero y postnatal durante la transferencia de embriones. Se ha identificado el VMV mediante técnicas de PCR en ovario, oviducto y útero, y se ha observado que las células de los folículos ováricos y ovocitos permanecen libres de infección (Cortez Romero et al, 2006;Cortez-Romero et al, 2011). Lamara y colaboradores (Lamara et al, 2001;Lamara et al, 2002b) observaron que células epiteliales del oviducto de cabras infectadas podrían ser infectadas in vitro con virus CAEV, aunque no hay evidencias de la infección de estas células in vivo.…”

“…La detección mediante PCR de VMV suele hacerse a partir de células mononucleares sanguíneas Reina et al, 2009a), aunque en ocasiones el bajo número de células infectadas circulantes reduce la sensibilidad . La técnica de la PCR ha descrito en diferentes tejidos, en sangre, leche o semen (Extramiana et al, 2002;Peterson et al, 2008;Cortez-Romero et al, 2011). También es frecuente la realización de la PCR en bloques de parafina de archivo (Gómez et al, 1999;González et al, 2001).…”