Small ruminant lentiviruses: economic and productive losses, consequences of the disease

Azevedo, Dalva Alana Aragão de; Santos, Vanderlan Warlington Souza dos; Sousa, Ana Lídia Madeira de; Peixoto, Renato Mesquita; Pinheiro, R. R.; Andrioli, A.; Teixeira, Maria Fátima da Silva

doi:10.1590/1808-1657000552016

Cited by 9 publications

(15 citation statements)

References 56 publications

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“…A artrite encefalite caprina (CAE) e a maedivisna (MV) são doenças infectocontagiosas causadas pelos LVPRs, retrovírus não oncogênicos, responsáveis por acarretar perdas produtivas e reprodutivas, e consequentemente econômicas [10]. Estruturalmente os lentivírus apresentam uma forma esférica, medindo de 80 a 100 nm envelopado por uma bicamada de lipídeos (envelope), a qual surge da membrana celular da célula hospedeira [66].…”

Section: Características Gerais E Resposta Imunológicaunclassified

“…O uso dessa técnica no imunodiagnóstico de LVPRs surgiu a partir do momento em que se constatou a carência por um teste que permitisse um resultado mais preciso, aliando altos índices de sensibilidade e especificidade. Associado a isso, a eficácia que o mesmo apresenta frente a outros testes sorológicos, permite otimizar e realizar estratégias de controle, visando reduzir os impactos produtivos, reprodutivos e econômicos que são ocasionadas com o estabelecimento desses agentes virais em um rebanho [10].…”

Section: Lentivírus De Pequenos Ruminantesunclassified

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Western Blot in Immunodiagnosis of Small Ruminant Lentivirus

Peixoto

Araújo

Pinheiro

2021

Acta Scientiae. Vet.

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Background: Small ruminant lentiviruses (SRLV) belong to genus Lentivirus, family Retroviridae. These viruses cause caprine arthritis encephalitis (CAE) and maedi visna (MV), infectious diseases that cause economic, production, and reproductive losses. There are no effective treatments or vaccines for these diseases. Thus, early detection via serology has great importance for control of SRLV. Therefore, the objective of this review is to demonstrate the potential of the western blot (WB) test as an immunodiagnostic test for SRLV. Review: In general, immunodiagnosis of SRLV is performed via agar gel immunodiffusion (AGID) and indirect enzyme-linked immunosorbent assay (ELISA), which can detect antibodies in several different biological samples but is used preferably with serum and blood plasma. However, WB has demonstrated efficacy in the early diagnosis of immunoglobulins against SRLV, presenting higher sensitivity and specificity than the serological tests usually used, because this technique can detect antibodies at a dilution as much as 256 times greater than that of AGID and 32 times greater than that of ELISA. SRLV infection and consequent immunological activation result in the induction of cellular and humoral responses. Additionally, around the third week, production of antibodies directed mainly toward viral capsid proteins (p25 and p28) occurs. After the fifth week, production of immunoglobulins directed toward other viral proteins occurs. Because of the persistence of SRLV infection, serology is considered to be the most practical means to diagnosis. Each serological test has a percentage specificity and distinct sensitivity, as well as advantages and disadvantages in its applicability. It should be noted that there is no gold standard test for diagnosis of SRLV infection. Moreover, SRLV are characterized by escape mechanisms such as genetic diversity, mutagenic potential, viral intermittence, and the process of compartmentalization, which make immunodiagnosis more difficult. In addition, positive animals tend to present unstable levels of antibodies over weeks, months, and even years. In this context, WB, with early antibody detection, has been proven to be a refined and more accurate technique than other immunodiagnostic tests for SRLV. WB allows the simultaneous resolution of several immunogenic antigens present in a sample, and this feature provides it with greater reliability, differentiates it from other immunological methods, and accredits it as a test of wide applicability. Epidemiological and immunological dynamics studies often use WB in the immunodynamic diagnosis of SRLV. Serum, blood plasma, and seminal plasma are typical biological materials used in the serological diagnosis of SRLV with WB, expanding its potential as an immunodiagnosis method.Conclusion: WB is the most accurate serological technique for SRLV. It is more capable of accurate diagnosis because the genetic diversity that characterizes such lentiviruses and their various immune system escape mechanisms routinely hinder traditional diagnosis. Additionally, this test has been used widely in studies of SRLV for various purposes, but mainly in studies of epidemiological and immunological dynamics, using serum, blood plasma, or seminal plasma. However, independently of the biological sample tested, WB maintains high sensitivity and precision in immunodiagnosis, making it a refined and valid technique for SRLV control programs.

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Section: Características Gerais E Resposta Imunológicaunclassified

Section: Lentivírus De Pequenos Ruminantesunclassified

Western Blot in Immunodiagnosis of Small Ruminant Lentivirus

Peixoto

Araújo

Pinheiro

2021

Acta Scientiae. Vet.

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“…Goat and sheep production are associated with traditional systems of subsistence and with economic factors, where animal production tends to be more intensive and demands more efficient production systems (GUILHERME et al, 2017). However, health management with late diagnoses of diverse diseases of different etiologies drastically interferes in the performance of these activities (AZEVEDO et al, 2017). Among the most relevant health problems are the infections caused by small ruminant lentiviruses (SRLVs).…”

Section: General Characteristics Of Small Ruminant Lenvirus Infectionsmentioning

confidence: 99%

“…These diseases cause considerable losses in goat and sheep productions, which may compromise the profitability of the animal farm (AZEVEDO et al, 2017). In addition, the main clinical signs of both infections include arthritis, encephalitis, mastitis and, less frequently, respiratory conditions.…”

Section: General Characteristics Of Small Ruminant Lenvirus Infectionsmentioning

confidence: 99%

Sodium dodecyl sulfate as a viral inactivator and future perspectives in the control of small ruminant lentiviruses

et al. 2019

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Infections by small ruminant lentiviruses (SRLVs) affect goats and sheep causing chronic multisystemic diseases that generate great economic losses. The caprine lentivirus (CLV) and the ovine lentivirus (OLV) present tropism for cells of the monocyte/macrophage lineage, which are directly associated with the main route of transmission through the ingestion of milk and colostrum from infected animals. In this manner, controlling this route is of paramount importance. Currently, researches have investigated the use of chemical additives in milk that can preserve colostrum or milk and inactivate microbiological agents. Among the compounds, sodium dodecyl sulfate (SDS) has been shown to be satisfactory in the chemical inactivation of HIV and CLV in milk, and also as a biocide in goat colostrum.

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“…After the first record of the disease, by Moojen, Soares, Ravazzolo, Pizzol and Gomes (1986) in the state of Rio Grande do Sul, studies have been carried out and shown that the virus has been spreading in Brazil with frequencies that vary according to the type of exploitation, rearing system and breeds used: São Paulo = 15.1% (30/199) (Lara et al, 2013) to 34.9% (96/275) (Madureira & Gomes, 2007); Minas Gerais = 49.5% (531/1072) (Nascimento-Penido, Penido, Galinari, Heinemanns, & Leite, 2017); Rio de Janeiro = 14.1% (79/562) (Cortez-Moreira, Oelemann, & Lilenbaum, 2005); Sergipe = 5.03% (34/675) (Rizzo et al, 2018); Bahia = 0.29% (2/693) (Lima et al, 2013a); Ceará = 40.73% (101/248) (Melo & Franke, 1997); Pernambuco = 18.01% (76/422) (Silva et al, 2012). Pinheiro, Ximenes, Andrioli and Texeira (2009), Lima et al (2013b) and Azevedo et al (2017) identified a total of 73 serological surveys carried out in Brazil. Some studies have shown the economic losses associated with the disease and its risk factors (Alves et al, 2017;Rizzo et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Efficacy of measures to control caprine arthritis-encephalitis in dairy herd with high clinical and serological prevalence

Alcindo

Simões

Pinheiro

et al. 2020

Semina: Ciênc. Agrár.

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This study examined the effectiveness of control measures for caprine arthritis-encephalitis in a herd with 431 dairy goats in an intensive rearing system. All animals older than six months were initially tested by agar gel immunodiffusion (AGID) and separated into seropositive and seronegative. Control measures were implemented for two years and ten months. Five serological examinations were subsequently performed two by AGID and three by the Western Blot (WB) technique. In these tests, animals that tested negative in the previous serological examination were evaluated along with those older than six months which had not yet been examined. The effectiveness of control was evaluated based on the incidence of the disease. Seroconverted animals were stratified according to age, physiological status and dam serology. For the effect of time, logistic regression was performed at the 5% significance level, with values converted into likelihood. General incidence and incidence as a function of age and physiological status were evaluated by analysis of variance, with means compared by Tukey’s test at 5% significance. The ratio test was used for incidence and physiological status, and the agreement between the AGID and WB tests was determined by the Kappa coefficient. Animals that seroconverted and were born to positive dams were compared with those born to dams negative at birth by the Chi-square test, and the same was applied for the number of discarded animals. Initially, 54.24% (179/330) positive and 257 seroconverted animals were identified after the start of control. Higher incidence occurred in the animals aged between 13 and 36 months and in lactating does. Seroconversions among offspring of seropositive dams were higher than in the offspring of seronegative dams (p < 0.001). High infection rates were identified in the sires. The obtained results were not satisfactory, as the measures did not help to prevent new cases, indicating that there are moments of infection yet to be elucidated. On farms that aim to control the disease, the following measures are required in addition to those already recommended: use of diagnostic tests with less frequency; application of high-sensitivity tests in the offspring; immediate separation of kids from dams at birth; separation of kids according to the serological status of the dams; inclusion of kids from unsupervised births in the group of kids from positive dams; and keeping positive and negative animals on different farms or greatly distanced. In herds for which there is an intention to establish control, it is important to determine whether the productive losses associated with the disease are greater than the costs of implementing more efficient measures.

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Small ruminant lentiviruses: economic and productive losses, consequences of the disease

Cited by 9 publications

References 56 publications

Western Blot in Immunodiagnosis of Small Ruminant Lentivirus

Western Blot in Immunodiagnosis of Small Ruminant Lentivirus

Sodium dodecyl sulfate as a viral inactivator and future perspectives in the control of small ruminant lentiviruses

Efficacy of measures to control caprine arthritis-encephalitis in dairy herd with high clinical and serological prevalence

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