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Olech M. The genetic variability of small-ruminant lentiviruses and its impact on tropism, the development of diagnostic tests and vaccines and the effectiveness of control programmes. J Vet Res 2023; 67:479-502. [PMID: 38130459 PMCID: PMC10730557 DOI: 10.2478/jvetres-2023-0064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 11/13/2023] [Indexed: 12/23/2023] Open
Abstract
Introduction Maedi-visna virus and caprine arthritis encephalitis virus are two closely related lentiviruses which cause multisystemic, progressive and persistent infection in goats and sheep. Because these viruses frequently cross the species barrier, they are considered to be one genetic group called small-ruminant lentiviruses (SRLV). They have in vivo tropism mainly for monocytes and macrophages and organ tropism with unknown mechanisms. Typical clinical signs are pneumonia in sheep, arthritis in goats, and mastitis in both species. Infection with SRLV cannot currently be treated or prevented, and control programmes are the only approaches to avoiding its spread. These programmes rely mainly on annual serological testing and elimination of positive animals. However, the high genetic and antigenic variability of SRLV complicate their early and definitive diagnosis. The objective of this review is to summarise the current knowledge of SRLV genetic variation and its implications for tropism, the development of diagnostic tests and vaccines and the effectiveness of control and eradication programmes. Material and Methods Subject literature was selected from the PubMed and the Google Scholar databases. Results The high genetic diversity of SRLV affects the performance of diagnostic tools and therefore control programmes. For the early and definitive diagnosis of SRLV infection, a combination of serological and molecular tests is suggested. Testing by PCR can also be considered for sub-yearling animals. There are still significant gaps in our knowledge of the epidemiology, immunology and biology of SRLV and their impact on animal production and welfare. Conclusion This information may aid selection of the most effective SRLV spread reduction measures.
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Affiliation(s)
- Monika Olech
- Department of Pathology, National Veterinary Research Institute, 24-100Puławy, Poland
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Longitudinal Study on Seroreactivity of Goats Exposed to Colostrum and Milk of Small Ruminant Lentivirus-infected Dams. J Vet Res 2022; 66:511-521. [PMID: 36846043 PMCID: PMC9945002 DOI: 10.2478/jvetres-2022-0071] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 12/07/2022] [Indexed: 12/27/2022] Open
Abstract
Introduction Small ruminant lentivirus (SRLV) causes caprine arthritis-encephalitis in goats and maedi-visna disease in sheep. Transmission is via ingestion of colostrum and milk from infected dams or long-term direct contact between animals. Lifelong seroconversion can occur several weeks after infection via ingestion. However, sub-yearling lambs that ingest contaminated colostrum may be able to clear the infection and become seronegative. Whether a similar phenomenon occurs in goats remains unknown. Therefore, the serological status of goats was studied longitudinally from the moment of natural exposure to colostrum and milk of SRLV-positive dams through the age of 24 months. Material and Methods Between February 2014 and March 2017 a dairy goat herd was studied which had been infected with SRLV for more than 20 years and carried maedi-visna virus-like genotype A subtype A17. Thirty-one kids born to dams seropositive for SRLV for at least a year beforehand were followed. They ingested colostrum immediately after birth and then remained with their dams for three weeks. The goats were tested serologically every month using two commercial ELISAs. The clinical condition of the goats was also regularly assessed. Results Out of 31 goats, 13 (42%) seroconverted at the age ranging from 3 to 22 months with a median of 5 months. Two goats seroconverted in the second year of life. The other eleven did so before the age of one year; two of these reverted to seronegative status. Only 9 out of 31 goats (29%) seroconverted in the first year of life and remained seropositive. They were early and stable seroreactors to which SRLV was transmitted lactogenically. The age at which they seroconverted ranged from 3 to 10 months with a median of 5 months. In 8 of the 18 persistently seronegative goats, a single isolated positive result occurred. No goats showed any clinical signs of arthritis. The level of maternal antibodies at the age of one week did not differ significantly between the stable seroreactors and the remainder. Conclusion Seroconversion appears to occur in less than 50% of goats exposed to heterologous SRLV genotype A via ingestion of colostrum and milk from infected dams and is delayed by 3-10 months. The natural lactogenic route of transmission of SRLV genotype A in goats appears to be less effective than this route of genotype B transmission reported in earlier studies.
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Furtado Araújo J, Andrioli A, Pinheiro RR, Peixoto RM, de Sousa ALM, de Azevedo DAA, Lima AMC, Nobre JA, Amaral GP, Brandão IS, da Silva Teixeira MF. Detection and isolation of small ruminant lentivirus in the amniotic fluid of goats. Comp Immunol Microbiol Infect Dis 2021; 78:101693. [PMID: 34399377 DOI: 10.1016/j.cimid.2021.101693] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 07/14/2021] [Accepted: 07/26/2021] [Indexed: 12/21/2022]
Abstract
The objective of this study was to verify the presence of small ruminant lentivirus in the amniotic fluid of goats using molecular tests and viral isolation by cocultivation in the amniotic fluid of naturally infected goats. The study analyzed eight goats: seven were small ruminant lentivirus-positive and one was negative. The amniotic fluid was collected from each of the eight animals during cesarean section at 147 days of pregnancy. Cocultivation was undertaken using secondary goat nictitating membrane cell cultures obtained by explant from a small ruminant lentivirus-negative calf followed by trypsinization and sub-cultivation of the cells for 63 days. During this period, five supernatant collections were performed for DNA extraction and subsequent nested polymerase chain reaction. DNA was extracted from the amniotic fluid after 3 h of cellular sedimentation, from which a sample of 600 μL was taken from the sediment and another 600 μL sample from the supernatant. After DNA extraction, nested polymerase chain reaction was performed. Of the eight goats, 62.5 % (05/08) were small ruminant lentivirus-positive, with 43.75 % (07/16) of the total samples positive when considering the two repetitions (supernatant and cell sediment). Moreover, positivity was confirmed by small ruminant lentivirus pro-viral DNA amplification in the cell supernatant throughout the cocultivation period. Small ruminant lentivirus were present in the amniotic fluid samples from the naturally infected goats indicating an intrauterine transmission route. Moreover, this biological fluid can be adopted for the diagnosis of these lentiviruse because it is an important risk factor related to intrauterine transmission.
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Affiliation(s)
- Juscilânia Furtado Araújo
- Doctorate Student in the Northeast Network in Biotechnology, State University of Ceará, Fortaleza, Ceará, Brazil.
| | | | | | - Renato Mesquita Peixoto
- Embrapa Goats and Sheep, Sobral, Ceará, Brazil; Scholarship for Regional Scientific Development of the National Council for Scientific and Technological Development (DCR-CNPq/FUNCAP), Level C, Brasilia, Distrito Federal, Brazil
| | | | | | - Ana Milena Cesar Lima
- Doctorate Student in Animal Science, Federal University of Piauí, Teresina, Piauí, Brazil
| | - Juliana Araújo Nobre
- Master Degree Student Medical Microbiology, Federal University of Ceará, Fortaleza, Brazil
| | - Gabriel Paula Amaral
- Undergraduate Student in Zootechnics, State University of Acaraú Valley, Sobral, Ceará, Brazil
| | - Iane Sousa Brandão
- Undergraduate Student in Biological Sciences, State University of Acaraú Valley, Sobral, Ceará, Brazil
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Furtado Araújo J, Andrioli A, Pinheiro RR, Sider LH, de Sousa ALM, de Azevedo DAA, Peixoto RM, Lima AMC, Damasceno EM, Souza SCR, Teixeira MFDS. Vertical transmissibility of small ruminant lentivirus. PLoS One 2020; 15:e0239916. [PMID: 33206648 PMCID: PMC7673514 DOI: 10.1371/journal.pone.0239916] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 09/15/2020] [Indexed: 12/18/2022] Open
Abstract
This study aimed to evaluate by means of Nested Polymerase Chain Reaction (nPCR), co-cultivation and sequencing, with genetic comparison between strains (mother/newborn), the occurrence of vertical transmission of Small Ruminant Lentiviruses (SRLV) from naturally occurring nannies infected for their offspring. For the detection of SRLV seropositive progenitors, blood was collected from 42 nannies in the final third of gestation in tubes with and without anticoagulant. The diagnostic tests used were Western Blot (WB) and nPCR. During the period of birth, the same blood collection procedure was performed on 73 newborns at zero hours of birth, with the same diagnostic tests. Seventeen blood samples from seven-day-old kids, proven positive for SRLV by nPCR, chosen at random, were subjected to coculture in goat synovial membrane (GSM) cells for 105 days. The pro-viral DNA extracted from the cell supernatant from the coculture was subjected to nPCR. For DNA sequencing from the nPCR products, nine positive samples were chosen at random, four nannies with their respective offspring, also positive. Each sample was performed in triplicate, thus generating 27 nPCR products of which only 19 were suitable for analysis. Among the 42 pregnant goats, in 50% (21/42) pro-viral DNA was detected by nPCR, while in the WB, only 7.14% (3/42) presented antibodies against SRLV. Regarding neonates, of the 73 kids, 34 (46.57%) were positive for the virus, using the nPCR technique, while in the serological test (WB), three positive animals (4.10%) were observed. The coculture of the 17 samples with a positive result in the nPCR was confirmed in viral isolation by amplification of the SRLV pro-viral DNA. When aligned, the pro-viral DNA sequences (nannies and their respective offspring) presented homology in relation to the standard strain CAEV Co. It was concluded that the transmission of SRLV through intrauterine route was potentially the source of infection in the newborn goats.
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Affiliation(s)
| | | | | | | | | | | | - Renato Mesquita Peixoto
- Embrapa Goats and Sheep, Sobral, Ceará, Brazil
- Scholarship for Regional Scientific Development of the National Council for Scientific and Technological Development (DCR-CNPq/FUNCAP), level C, Brasilia, Distrito Federal–DF, Brazil
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Rodrigues ADS, Pinheiro RR, Brito RLLD, Oliveira LS, Oliveira ELD, Santos VWSD, Andrioli A, Souza TSD, Dias RP, Teixeira MFDS. Evaluation of caprine arthritis-encephalitis virus transmission in newborn goat kids. ARQUIVOS DO INSTITUTO BIOLÓGICO 2018. [DOI: 10.1590/1808-1657000542016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
Abstract
ABSTRACT: Caprine arthritis encephalitis causes considerable losses in goat production. The main form of the caprine arthritis encephalitis virus transmission is through the ingestion of colostrum or milk from infected females. However, some transmissions cannot be explained in this manner. Therefore, this study aimed to evaluate transplacental transmission of caprine arthritis encephalitis virus. Blood samples were collected from 283 newborn kids of Anglo-Nubian and Saanen breeds born from seropositive and seronegative goats. Samples were collected immediately after birth and analyzed with agarose gel immunodiffusion and western blot. All samples were negative in the agarose gel immunodiffusion. However, the western blot test demonstrated that four kids were born positive for caprine arthritis encephalitis virus. This result indicates that although in a low frequency (1.4%), there is a possibility of transplacental transmission of small ruminant lentivirus.
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