Small Ruminant Lentiviruses: Genetic Variability, Tropism and Diagnosis
نویسندگان
چکیده
Small ruminant lentiviruses (SRLV) cause a multisystemic chronic disease affecting animal production and welfare. SRLV infections are spread across the world with the exception of Iceland. Success in controlling SRLV spread depends largely on the use of appropriate diagnostic tools, but the existence of a high genetic/antigenic variability among these viruses, the fluctuant levels of antibody against them and the low viral loads found in infected individuals hamper the diagnostic efficacy. SRLV have a marked in vivo tropism towards the monocyte/macrophage lineage and attempts have been made to identify the genome regions involved in tropism, with two main candidates, the LTR and env gene, since LTR contains primer binding sites for viral replication and the env-encoded protein (SU ENV), which mediates the binding of the virus to the host's cell and has hypervariable regions to escape the humoral immune response. Once inside the host cell, innate immunity may interfere with SRLV replication, but the virus develops counteraction mechanisms to escape, multiply and survive, creating a quasi-species and undergoing compartmentalization events. So far, the mechanisms of organ tropism involved in the development of different disease forms (neurological, arthritic, pulmonary and mammary) are unknown, but different alternatives are proposed. This is an overview of the current state of knowledge on SRLV genetic variability and its implications in tropism as well as in the development of alternative diagnostic assays.
منابع مشابه
Serological study of small ruminant lentiviruses in sheep population of Khorasan-e-Razavi province in Iran
Maedi-Visna (MV) virus and caprine arthritis encephalitis (CAE) virus known as small ruminant lentiviruses (SRLVs) cause chronic diseases in susceptible animals. The main reservoirs of these viral agents are sheep and goat. In sheep, MV virus causes a disease as the same name of the virus. This is the first seroprevalence survey of SRLVs in sheep population of Khorasan-e-Razavi province in Iran...
متن کاملGenetic diversity of small-ruminant lentiviruses: characterization of Norwegian isolates of Caprine arthritis encephalitis virus.
Small-ruminant lentiviruses (SRLVs), including Caprine arthritis encephalitis virus (CAEV) in goats and maedi-visna virus (MVV) in sheep, are lentiviruses that, despite overall similarities, show considerable genetic variation in regions of the SRLV genome. To gain further knowledge about the genetic diversity and phylogenetic relationships among field isolates of SRLVs occurring in geographica...
متن کاملExpanding Possibilities for Intervention against Small Ruminant Lentiviruses through Genetic Marker-Assisted Selective Breeding
Small ruminant lentiviruses include members that infect sheep (ovine lentivirus [OvLV]; also known as ovine progressive pneumonia virus/maedi-visna virus) and goats (caprine arthritis encephalitis virus [CAEV]). Breed differences in seroprevalence and proviral concentration of OvLV had suggested a strong genetic component in susceptibility to infection by OvLV in sheep. A genetic marker test fo...
متن کاملField evaluation of a gag/env heteroduplex mobility assay for genetic subtyping of small-ruminant lentiviruses.
Small-ruminant lentiviruses (SRLVs) display a high genetic diversity and are currently classified into five genotypes and an increasing number of subtypes. The co-circulation of subtypes in restricted geographical regions, combined with the occurrence of cross-species infection, suggests the need for development of a large-scale screening methodology for rapid monitoring of the prevalence of th...
متن کامل