Characterization of minimal lesions related to the. The main histological features are chronic interstitial inflammation with dense cellular infiltration, hyperplasia of smooth musculature in alveolar septa, and slight fibrosis. Maedivisna by iowa state university center for food. Maedi progressive interstitial pneumonia and visna meningoleucoencephalitis are slowly progressive non febrile contagious diseases of sheep. Visna maedi virus an overview sciencedirect topics. Petursson and rikke hoffj0rgensen the concept of slow viral infections was first put forward in 1954 by dr. This disease belongs to the retroviridae family the maedivisna virus is also known as. Mvv particles are bounded by an envelope with projections loosely attached to its surface.
The presence of the virus was confirmed by immunohistochemistry and in some cases by pcr on frozenthawed or paraffinembedded tissue samples. Although mv is prevalent in many countries, it had not been reported in japan. The technique allows the plaques formed by these viruses to be localized without disturbing the hostcell substrate of sheep choroid plexus cells or the gelled maintenance medium over the hostcell monolayer. The aim of this work was to investigate whether an enzymelinked immunosorbent assay elisa was useful for early detection of maedivisna virus mvv infection in sheep under field conditions. A different strain of the same virus causes a lymphocytic interstitial pneumonia referred to as maedi. It was originally a significant cause of death in the epizootic of maedivisna that occurred in iceland from 1933 to 1965. Pdf on jan 1, 2010, michel pepin and others published maedi. The outbreak demonstrated the need for a nationwide surveillance programme, which started in november 2003 4, 6.
In most cases, maedivisna virus infection is characterised by a subclinical, persistent viruscarrier state. This article is from the journal of veterinary medical science, volume 76. Maedi visna mv is considered to be one of the iceberg diseases of sheep. Srlvs include maedi visna virus mvv, which mainly occurs in sheep, and caprine arthritis encephalitis. The viruses that produce maedivisna virus mvv and caprine arthritisencephalitis virus. Visnamaedi is a persistent untreatable disease affecting millions of sheep worldwide. A simple and direct plaque assay for maedi virus, two strains of progressive pneumonia virus, and two strains of visna virus has been developed and evaluated. A visnamaedilike disease was found in a corriedale sheep from which a retrovirus sharing the group antigen of visnaprogressive pneumonia virus was isolated from lung, brain, and spleen. An amino acid substitution ek at position 35 of the transmembrane protein 154 tmem154 as well as a deletion in the chemokine cc motif receptor type 5 gene ccr5 were reported to be associated with the serological mv status andor the srlv provirus. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext.
Ultrastructural studies on maedivisna virus springerlink. Bronchoalveolar lavage was performed to recover alveolar cell pools from which cytocentrifuge preparations were made, single and double immunocytochemical techniques were applied to study. Association of tmem154 variants with visnamaedi virus. The surveillance programme for maedi in norway in 2018. Pdf haematological parameters in blood of maedivisna.
Visna virus also known as visnamaedi virus, maedivisna virus and ovine lentivirus from the genus lentivirus and subfamily orthoretrovirinae, is a prototype retrovirus that causes encephalitis and chronic pneumonitis in sheep. Evaluation of two recombinant maedivisna virus proteins. We have used the pcr and hirt dna obtained from mvvinfected tissue culture cells as a template to generate a number of independently derived clones representing overlapping fragments of the gp5 region env of maedi visna virus mvv strain ev1. Dealing with maedi visna in uk sheep flocks in practice. The first page of the pdf of this article appears above. Maedi visna and caprine arthritis and encephalitis are economically important viral diseases that affect sheep and goats. A major route of transmission of visnamaedi virus vmv, an ovine lentivirus, is thought to be via the respiratory tract, by inhalation of either cellfree or cellassociated virus. This is incorrect as mv has not been reported in sheep in northern ireland. Two hundred sixty field serum specimens from 15 sheep flocks were tested in parallel with recombinant. Etiology, epizootiology and control of maedivisna in dairy. These diseases are caused by a group of lentiviruses called the small ruminant lentiviruses srlvs. Maedi is caused by visnamaedi virus vmv, a nononcogenic small ruminant lentivirus srlv of the family retroviridae. Diagnosis of the nervous form of maedivisna infection.
Maedi is an important, lifelong, and persistent viral disease of sheep and occurs in most countries, except australia and new zealand. Ep1073676b1 immunodiagnostic reagent for the detection. Maedivisna, cae programm tgd no tiergesundheitsdienst. Al ahmad mz, chebloune y, chatagnon g, pellerin jl, fieni f 2012. Abstractmaedivisna mv is a lentiviral disease of sheep caused by the maedivisna. Center for food security and public health technical. Maedi visna is an economically important viral disease of sheep that occasionally affects goats. Clinical and laboratory studies in an outbreak of maedivisna disease in a flock of sheep and goats were conducted. Pdf expression of the gp150 maedi visna virus envelope. Maedivisna virus mvv and caprine arthritisencephalitis virus are commonly known as small ruminant lentiviruses srlvs due to their genetic, structural, and pathogenic similarities. An elisa was used to detect antibodies to maedivisna virus in samples of serum and milk from individual sheep.
This group of diseases also includes border disease, caseous lymphadenitis, ovine johnes disease. Evaluation of a plaque assay for the maediprogressive. It was originally a significant cause of death in the epizootic of maedi visna that occurred in iceland from 1933 to 1965. Ovine visna maedi vm is caused by visnamaedi virus vmv, which together with caprine arthritisencephalitis virus are small ruminant. Sequence variation in the gp5 gene of maedi visna virus. Srlvs include maedivisna virus mvv, which mainly occurs in sheep, and caprine arthritis encephalitis virus caev, mainly found in goats, as well as other srlv. Evaluation of an elisa to detect antibodies to maedivisna. The major clinical signs were dyspnoea particularly on exercise, progressive fore and hindlimb ataxia and balance defects, mammary induration and multilimb lameness, occasionally with enlarged carpal joints. Although most infections are subclinical, a minority of animals develops progressive, untreatable disease syndromes including dyspnea maedi or. In the late thirties both conditions maedidyspnoea and visnawasting were observed for the first time in iceland and were considered to be two different diseases. However, in heavily infected flocks, economically significant disease does occur, mainly apparent as illthrift and chronic respiratory disease maedi in older ewes and as an indurative mastitis, which can result in delayed weight gain of suckled lambs.
Pdf outbreak of maedivisna in sheep and goats in palestine. The histopathology of natural and experimental maedi, a slowviral pneumonia of sheep, was studied. Maedivisna and caprine arthritis and encephalitis are economically important viral diseases that affect sheep and goats. Maedivisna was accidentally introduced into iceland by importation of a flock of karakul sheep intended for breeding. Maedivisna mv in sheep is caused by maedivisna virus mvv, a small ruminant lentivirus srlv that causes chronic infection and inflammatory lesions in infected animals. Early events in immune evasion by the lentivirus maedivisna occurring within infected lymphoid tissue. The expression of gag p15, p25 and env gene products in ovine lentivirusinfected cells was studied in 20 adult texel ewes seropositive to maedivisna virus and 10 seronegative matched controls. In historic times, they occupied the area between paionia and thrace, on the southwestern fringes of thrace, along the middle course of the strymon, between the kresna gorge and the rupel pass presentday southwestern bulgaria. Visnamaedi virus vmv, familie retroviridae genus lentivirus. An overview of the number of new infected flocks registered each year up to 2018 is given in figure 1.
The maedivisna virus is also known as zwoegerziekte virus, ovine progressive pneumonia virus, and the graaffreinet. It is known as visna when found in the brain, and maedi when infecting the lungs. A description of the epidemiology is given followed by possible methods of control. Etiology, epizootiology and control of maedivisna in. Maedivisna virus infection in a flock of sheep in scotland was associated with respiratory disease, neurological disease, mastitis and lameness.
Serological investigation of maedivisna in sheep with chronic respiratory disease in erbil, iraq. Download article pdf view full text htmlmachine readable. Haematological parameters in blood of maedivisna virusinfected and uninfected sheep. Immunodiagnostic reagent for the detection of maedivisna virus and caev infection download pdf info publication number wo1999057141a1. Visna and maedi viruses appeared to be immunologically identical when examined in gel diffusion tests and. Maedivisna virus infection in practice in practice. Maedi visna caev serum verification elisa creating a userdefined assay is an easy process of two tasksediting an xchek file to allow you to create an assay, and then creating the assay within xchek. Defined segments of the gag polyprotein and transmembrane envelope glycoprotein from maedivisna virus were expressed as glutathione stransferase fusion proteins in escherichia coli and evaluated singly and in combination for use in an enzymelinked immunosorbent assay elisa. Maedivisna, a disease caused by small ruminant lentiviruses srlvs, is present in sheep from many countries, also including germany. Sequentially obtained serum samples n 1,941 were studied for 4.
First survey on association of tmem154 and ccr5 variants. Maedi means shortness of breath in the icelandic language. Ovine lentivirus maedivisna virus protein expression in. Ultrastructural studies of maedivisna virus mvv particles isolated from tissue culture fluids of mvvinfected cells as well as cultured cells infected with mvv were performed. Recent experimental work performed in an attempt to resolve the pathogenetic features of slowness and persistence of infection, characteristic of maedivisna, is covered. A brief history of the occurrence of maedivisna or maedivisna related diseases is given. Stewart odendhal, in the geographical distribution of animal viral diseases, 1983. The assay was also applied to samples of bulktank milk. Visna virus from the genus lentivirus and subfamily orthoretrovirinae, is a prototype retrovirus. Pdf isolation of maedivisna virus from a sheep in japan. Expression of the gp150 maedi visna virus envelope precursor protein by mammalian expression vectors. Maedivisna virus mvv and caprine arthritisencephalitis virus are commonly known as small ruminant lentiviruses srlvs due. Comparative studies of visna and maedi viruses as antigens.
Pneumonia and mastitis are its predominant clinical manifestations, and the tissues infected by mvv are mainly the lungs, the mammary gland, the nervous system and the joints. Bjorn sigurdsson, an icelandic physician who had been studying some sheep diseases which were introduced into iceland with the importation of a foreign breed of sheep in 1933. Characterization of minimal lesions related to the presence of visna. Maedi visna virus mvv and caprine arthritisencephalitis virus are commonly known as small ruminant lentiviruses srlvs due. Maedivisna mv is a lentiviral disease of sheep caused by the maedivisna virus mvv. Pdf comparative studies of visna and maedi viruses as. Tmem154 gene has been associated with visnamaedi susceptibility in us sheep we evaluated the effect of tmem154 in turkish sheep from around the country results reported in north america were validated in. Early events in immune evasion by the lentivirus maedi. Maedivisna mv in sheep is caused by maedivisna virus mvv, a small ruminant lentivirus srlv that causes chronic. Role of alveolar macrophages in respiratory transmission. In order to characterize the complete range of lesions, especially minimal, affecting mammary gland and viral antigen distribution and target cells using immunohistochemistry in naturally visnamaedi vm 84 infected sheep were studied, fortyfour from flocks with clinical cases a and 35 randomly sampled from two abattoirs b together with five negative controls c. This chapter presents a classification and description of the maedivisna virus. The clinical findings of the disease were loss of wool, dyspnea and.
1324 1311 760 1574 1570 417 815 457 1155 85 1203 1625 1503 64 226 631 1470 475 335 620 1426 333 637 1460 165 420 894 62 349 647 871 1160 447 495 4 1478