Role of Alveolar Macrophages in Respiratory Transmission of Visna/Maedi Virus

McNeilly, Tom N.; Baker, Alison; Brown, Jeremy K.; Collie, David; MacLachlan, Gerry; Rhind, Susan; Harkiss, G. D.

doi:10.1128/jvi.02148-07

Cited by 41 publications

(40 citation statements)

References 42 publications

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“…Their results indicated that the LTR determined the extended cell tropism of the MVV. Therefore, in live animals, virus isolation can be conducted on peripheral blood, milk and inhalation of infected alveolar macrophages (Christodoulopoulos 2006;Gil et al 2006;McNeilly et al 2008;Barquero et al 2011). At necropsy, MVV can be isolated from the lungs, mediastinal lymph nodes, spleen, third eyelids and kidneys of affected animals (Capucchio et al 2003;Angelopoulou et al 2006;Benavides et al 2006;Laamanen et al 2007).…”

Section: Discussionmentioning

confidence: 98%

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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Section: Discussionmentioning

confidence: 98%

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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“…The highest BFV DNA load was observed in lungs, liver, and spleen of experimentally inoculated calves at the early phase p.i., while in long-term-infected sheep and naturally infected cows, much lower overall DNA loads were detected. Detection of FV DNA in a particular tissue does not necessarily indicate active virus replication since alveolar macrophages and areas of lymphocyte aggregation or lymphoid proliferation are known to act as latent reservoirs of other retroviruses like Maedi-Visna virus or human immunodeficiency virus (HIV) (54,55,56,57). Furthermore, since lymphocytes have been previously identified as targets of FV infection (58), the presence of viral DNA in lungs can be explained by BFV-infected lymphocyte and monocyte-derived macrophage infiltration or by high vascularization and an enrichment of infected leukocytes.…”

Section: Discussionmentioning

confidence: 99%

Similar Patterns of Infection with Bovine Foamy Virus in Experimentally Inoculated Calves and Sheep

Materniak

Hechler

Löchelt

et al. 2013

J Virol

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bFoamy viruses (FVs) are the least known retroviruses commonly found in primates, cats, horses, and cattle. Although FVs are considered apathogenic, simian and feline FVs have been shown to be associated with some transient health abnormalities in animal models. Currently, data regarding the course of infection with bovine FV (BFV) are not available. In this study, we conducted experimental infections of natural (cattle) and heterologous (sheep) hosts with the BFV 100 isolate and monitored infection patterns in both hosts during the early phase postinoculation as well as after long-term infection. Four calves and six sheep inoculated with BFV 100 showed no signs of pathology but developed persistent infection, as confirmed by virus rescue, consistent detection of BFV-specific antibodies, and presence of viral DNA. In both hosts, antibodies against BFV Gag and Bet appeared early after infection and persisted at high and stable levels while seroreactivity toward Env was consistently detectable only in BFV-infected sheep. Interestingly, the BFV proviral DNA load was highest in lung, spleen, and liver and moderate in leukocytes, while salivary glands contained either low or undetectable DNA loads in calves or sheep, respectively. Additionally, comparison of partial BFV sequences from inoculum and infected animals demonstrated very limited changes after long-term infection in the heterologous host, clearly less than those found in BFV field isolates. The persistence of BFV infection in both hosts suggests full replication competence of the BFV 100 isolate with no requirement of genetic adaptation for productive replication in the authentic and even in a heterologous host.

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“…27,77,83 Both cell-associated and cell-free OPPV and VISNA have been found in colostrum, milk, and bronchial alveolar lavage (BAL) fluid of the lung of serologically positive ewes. 10,39,52,53,56,57 The OPPV or VISNA in the BAL fluid is thought to be the major source of horizontal transmission in sheep; however, there have not been any reports demonstrating the shedding of OPPV, VISNA, or CAEV in oronasal secretions. Interestingly, although cell-associated OPPV, found in the colostrum or milk of 6-year-old, lactating ewes, in both meat and wool breeds, and transmitted to lambs, establishment of persistent infection based on the presence of peripheral provirus load and OPPV serum antibodies only occurred in 5% of lambs (1 of 22) during 6 years of surveillance (LM HerrmannHoesing, unpublished data, 2008).…”

Section: Transmission Sourcesmentioning

confidence: 99%

Diagnostic Assays Used to Control Small Ruminant Lentiviruses

Herrmann‐Hoesing

2010

J VET Diagn Invest

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Abstract. The serologic diagnostic tests, such as the agar gel immunodiffusion assay and various types of enzyme-linked immunosorbent assays (ELISAs), have contributed to the reduction of small ruminant lentivirus (SRLV) infections worldwide. Because there are no treatments or efficacious vaccines, the serologic diagnostic tests have supported most of the eradication efforts by testing and removal or separation of adult animals that generate antibodies to SRLVs. With the advent of molecular diagnostics, standard and quantitative polymerase chain reaction (PCR)-based assays for the detection of provirus in peripheral blood cells are becoming more common and aid in the detection of infected goats and sheep before antibody detection by ELISA in some animals. Performance of the serologic and molecular diagnostic tests is dependent upon a number of factors, including the format of the assay, the percentage of identity between the viral nucleotide sequences in a flock or herd of a certain geographic region and the sequences used to generate SRLV test reagents, and the intrinsic pathogenesis or amount of provirus and SRLV antibody generated in a species or individual small ruminant. In addition, small ruminant genomics may help with establishing genetic markers of SRLV infection and disease, which could also aid eradication or reduction of SRLVs from herds and flocks throughout the world.

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Role of Alveolar Macrophages in Respiratory Transmission of Visna/Maedi Virus

Cited by 41 publications

References 42 publications

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

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

Similar Patterns of Infection with Bovine Foamy Virus in Experimentally Inoculated Calves and Sheep

Diagnostic Assays Used to Control Small Ruminant Lentiviruses

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