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The complete gag gene from small ruminant lentiviruses (SRLV) encodes for a polyprotein of 55 kDa, known as p55gag. p55gag presents multiple antigenic epitopes, which can be recognized by antibodies, increasing the opportunity to detect SRLV-positive animals. Therefore, this polyprotein is considered an excellent candidate to use in diagnostic tests to detect antibodies against SRLV. Different studies have suggested that the selection of the recombinant antigen, which must be representative of the virus strains circulating in the test population, is crucial to avoid false negative results. Thus, the use of proteins from different viral strains isolated from goats or sheep of a given region or country may be a useful strategy to increase the ability to detect SRLV-infected animals. In the present study, the pMAL-p5X vector was used to express and purify p55gag (now called rp55gag for recombinant polyprotein 55 gag). The cloned gene was inserted downstream from the malE gene of Escherichia coli, which encodes a maltose-binding protein (MBP), resulting in the expression of an MBP fusion protein. The complete gag gene was amplified by RT-PCR. Finally, after digestion, the product was cloned into the pMAL-p5X vector and used to transform E. coli ER2325 cells. After the purification of MBP-rp55gag by affinity chromatography, the eluted fraction was observed by SDS-PAGE and Western Blot (WB). The WB was carried out with 85 serum samples from small ruminants previously analysed and compared by two commercial ELISAs. The results show that 76 of the serum samples were concordant with those by both ELISAs. Regarding the other nine serum samples, which showed discordant results between both ELISAs, were positive by WB. The results thus show that the rp55gag could be considered as an antigen in a confirmatory diagnostic assay to detect SRLV by WB. For this purpose, a future study with a high number of sera to determine the test specificity and sensitivity, using the p55gag of the circulating strain in Argentina will be necessary.

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Background: Small ruminant lentivirus (SRLV) belong to genus Lentivirus, family Retroviridae. These viruses causecaprine 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 hasgreat importance for control of SRLV. Therefore, the objective of this review is to demonstrate the potential of the westernblot (WB) test as an immunodiagnostic test for SRLV.Review: In general, immunodiagnosis of SRLV is performed via agar gel immunodiffusion (AGID) and indirect enzymelinked 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 immunoglobulinsagainst SRLV, presenting higher sensitivity and specificity than the serological tests usually used, because this techniquecan 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 thepersistence of SRLV infection, serology is considered to be the most practical means to diagnosis. Each serological testhas a percentage specificity and distinct sensitivity, as well as advantages and disadvantages in its applicability. It shouldbe noted that there is no gold standard test for diagnosis of SRLV infection. Moreover, SRLV are characterized by escapemechanisms such as genetic diversity, mutagenic potential, viral intermittence...(AU)

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A serological survey was carried out to assess the frequency of leptospirosis, small ruminants lentivirus (SRLV), and brucellosis in small ruminant herds in the Recôncavo Baiano, State of Bahia, Brazil, from February to December 2017. In four goat herds, 125 animals were tested for SRLV and leptospirosis, while in five sheep herds, 378 animals were tested for leptospirosis, brucellosis, and SRLV. Regarding leptospirosis, MAT detected 80% of goats and 15.34% of sheep seroreactive. Reactivity was most frequent to serogroups Autumnalis and Grippotyphosa in goats and sheep, respectively. Regarding SRLV, 8.8% of goats and 0.79% of sheep were reactive. Search for anti-B. ovis antibodies revealed 0.52% reactivity. In sheep, three animals showed simultaneous seroreactivity for SRLV and leptospirosis, while one animal had a serological response for brucellosis and leptospirosis. In goats, simultaneous seroreactivity for SRLV and leptospirosis was observed in only one animal. Leptospirosis was the most frequent of the three infectious diseases in investigated herds.(AU)

Foi realizado um inquérito sorológico para avaliar a frequência de ocorrência de leptospirose, lentiviroses de pequenos ruminantes (LVPR) e brucelose em rebanhos de pequenos ruminantes no Recôncavo Baiano, estado da Bahia, Brasil, no período de fevereiro a dezembro de 2017. Em quatro rebanhos de caprinos, foram testados 125 animais para LVPR e leptospirose, enquanto em cinco rebanhos de ovinos, foram testados 378 animais para leptospirose, brucelose e LVPR. Em relação à leptospirose, 80% das cabras e 15,34% das ovelhas foram sororreativas. Os sorogrupos de Leptospira spp. predominantes foram Autumnalis e Grippotyphosa para caprinos e ovinos, respectivamente. Em relação as LVPR, 8,8% dos caprinos e 0,79% dos ovinos foram reativos. Adicionalmente, a pesquisa de anticorpos Anti-B. ovis revelou 0,52% de ovinos reativos. Em ovinos, três animais apresentaram sororreatividade simultânea para LVPR e leptospirose, enquanto um animal teve resposta sorológica para brucelose e leptospirose. Em caprinos, sororreatividade simultânea para LVPR e leptospirose foi observada em apenas um animal. A leptospirose foi a doença infecciosa mais frequente nos rebanhos investigados.(AU)

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RESUMO

A serological survey was carried out to assess the frequency of leptospirosis, small ruminants lentivirus (SRLV), and brucellosis in small ruminant herds in the Recôncavo Baiano, State of Bahia, Brazil, from February to December 2017. In four goat herds, 125 animals were tested for SRLV and leptospirosis, while in five sheep herds, 378 animals were tested for leptospirosis, brucellosis, and SRLV. Regarding leptospirosis, MAT detected 80% of goats and 15.34% of sheep seroreactive. Reactivity was most frequent to serogroups Autumnalis and Grippotyphosa in goats and sheep, respectively. Regarding SRLV, 8.8% of goats and 0.79% of sheep were reactive. Search for anti-B. ovis antibodies revealed 0.52% reactivity. In sheep, three animals showed simultaneous seroreactivity for SRLV and leptospirosis, while one animal had a serological response for brucellosis and leptospirosis. In goats, simultaneous seroreactivity for SRLV and leptospirosis was observed in only one animal. Leptospirosis was the most frequent of the three infectious diseases in investigated herds.(AU)

Foi realizado um inquérito sorológico para avaliar a frequência de ocorrência de leptospirose, lentiviroses de pequenos ruminantes (LVPR) e brucelose em rebanhos de pequenos ruminantes no Recôncavo Baiano, estado da Bahia, Brasil, no período de fevereiro a dezembro de 2017. Em quatro rebanhos de caprinos, foram testados 125 animais para LVPR e leptospirose, enquanto em cinco rebanhos de ovinos, foram testados 378 animais para leptospirose, brucelose e LVPR. Em relação à leptospirose, 80% das cabras e 15,34% das ovelhas foram sororreativas. Os sorogrupos de Leptospira spp. predominantes foram Autumnalis e Grippotyphosa para caprinos e ovinos, respectivamente. Em relação as LVPR, 8,8% dos caprinos e 0,79% dos ovinos foram reativos. Adicionalmente, a pesquisa de anticorpos Anti-B. ovis revelou 0,52% de ovinos reativos. Em ovinos, três animais apresentaram sororreatividade simultânea para LVPR e leptospirose, enquanto um animal teve resposta sorológica para brucelose e leptospirose. Em caprinos, sororreatividade simultânea para LVPR e leptospirose foi observada em apenas um animal. A leptospirose foi a doença infecciosa mais frequente nos rebanhos investigados.(AU)

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Background: Small ruminant lentivirus (SRLV) belong to genus Lentivirus, family Retroviridae. These viruses causecaprine 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 hasgreat importance for control of SRLV. Therefore, the objective of this review is to demonstrate the potential of the westernblot (WB) test as an immunodiagnostic test for SRLV.Review: In general, immunodiagnosis of SRLV is performed via agar gel immunodiffusion (AGID) and indirect enzymelinked 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 immunoglobulinsagainst SRLV, presenting higher sensitivity and specificity than the serological tests usually used, because this techniquecan 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 thepersistence of SRLV infection, serology is considered to be the most practical means to diagnosis. Each serological testhas a percentage specificity and distinct sensitivity, as well as advantages and disadvantages in its applicability. It shouldbe noted that there is no gold standard test for diagnosis of SRLV infection. Moreover, SRLV are characterized by escapemechanisms such as genetic diversity, mutagenic potential, viral intermittence...

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Lentivirosis of small ruminants (LVPR) are chronic and degenerative infectious diseases, caused by Lentivirus, associated with numerous losses such as: drop in meat and milk production, predisposition to secondary infections, expenses with veterinary assistance and, even, early disposal of animals. In the northern region of Brazil, the epidemiological situation is poorly understood. Thus, this study aimed to determine the seropositivity of sheep for Lentivirus in Porto Acre city, Western Amazon, Brazil. 122 blood samples from sheep were collected and as a diagnostic method, agarose gel immunodiffusion was used, using the p28 protein of the capsid as antigen. The seropositivity of the sheep to the test was 8.2% (10/122). In 80% (4/5) of the investigated properties, the presence of seropositive animals was detected. It is worth noting that the acquisition of small ruminants from other states likely represented a risk to sheep health in the municipality of Porto Acre, Western Amazon, Brazil. It is concluded that there is a need for more systematic investigations on the prevalence of LVPR in the state of Acre.

As lentiviroses de pequenos ruminantes (LVPR) são enfermidades infecciosas crônicas e degenerativas, causadas por Lentivírus, associadas a inúmeros prejuízos como: queda na produção de carne e leite, predisposição a infecções secundárias, gastos com assistência veterinária e, até mesmo, descarte precoce dos animais. Na região norte do Brasil, a situação epidemiológica é pouco elucidada. Objetivou-se, assim, por meio deste estudo, determinar a soropositividade de ovinos para Lentivírus no município de Porto Acre, Amazônia Ocidental, Brasil. Foram coletadas 122 amostras de sangue de ovinos e como método diagnóstico foi empregada a imunodifusão em gel de agarose, utilizando a proteína p28 do capsídeo como antígeno. A soropositividade dos ovinos ao teste foi de 8,2% (10/122). Em 80% (4/5) das propriedades investigadas, detectou-se a presença de animais soropositivos. É válido ressaltar ainda que a aquisição de pequenos ruminantes advindos de outros estados provavelmente representou um risco à sanidade ovina no município de Porto Acre, Amazônia Ocidental, Brasil. Conclui-se que existe a necessidade de mais investigações sistemáticas sobre a prevalência de LVPR no estado do Acre.

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Background: Caprine Arthritis Encephalitis (CAE) is a disease that causes productive losses in dairy goat flocks due to thereduction in milk production, followed by lesions in joints and mammary glands. An early diagnosis is essential, consideringthat there is frequent occurrence of asymptomatic animals. Hence, this study aimed to perform a comparison of immunological and molecular based diagnostic tests, represented by Agar Gel Immunodiffusion (AGID), Western Blot (WB) andnested Polymerase Chain Reaction (nPCR). In addition, the mammary glands (MG) of dairy goats were clinically evaluated.Materials, Methods & Results: Blood collection and clinical examination were performed in 1191 dairy goats of 12 farms locatedin Northeastern and Southeastern regions of Brazil. Serological (AGID, WB) and molecular (nPCR) test results were comparedand the data, along with MG alterations, were analyzed using Epi-info 7 and WinEpiscope 2.0. Seroprevalence in AGID test was41.14% (490/1191). In WB, 51.47% (613/1191) of animals were seropositive and nPCR detected 69.44% (827/1191) positiveanimals. Hence, WB was more sensitive (P < 0.001) than AGID. However, nPCR detected more positive animals than AGID (P< 0.001) and WB (P < 0.001). The analysis of mammary glands revealed that 105 out of 1096 nanny goats presented alterations,of which 101 presented altered consistency, 16 presented elevated temperatures and 60 had enlarged retromammary lymph nodes.There was significant statistic difference (P < 0.05) only when comparing the results of serological tests with MG alterations.Discussion: In general, AGID technique is most frequently used when screening flocks for the disease due to the practicalityand low cost this test presents. However, the results demonstrated that AGID detected the lowest number of positive animals.This low sensitivity that the test presented may be attributed to its antigen-antibody interaction mechanism...(AU)

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FIV e FeLV são retrovírus associados principalmente com neoplasias. Dois testes rápidos são disponibilizados no Brasil para o diagnóstico dessas infecções: um kit de imunocromatografia de fluxo bidirecional (SNAP® Combo IDEXX) e um kit de imunocromatografia de fluxo lateral unidirecional (ALERE/BIONOTE Anigen Rapid). O objetivo deste estudo foi comparar o teste SNAP® com o teste ALERE. Amostras de sangue de 178 gatos foram testadas utilizando-se ambos os kits. A reação em cadeia de polimerase em tempo real (qPCR) foi empregada como método confirmatório para todos os resultados. O teste SNAP® apresentou sensibilidade e especificidade de 100% para FIV; a sensibilidade e a especificidade do teste ALERE foram de 96,15% e 98,68%, respectivamente. A sensibilidade e a especificidade para o FeLV foram de 93,02% e 96,30% para o teste SNAP® e de 90,70% e 97,78% para o teste ALERE. Ainda em relação ao FeLV, três amostras com resultado positivo na qPCR obtiveram resultado falso-negativo em ambos os testes. Não houve diferença estatisticamente significante entre os métodos. Considerando a qPCR como padrão-ouro, o teste SNAP® apresentou maior sensibilidade e especificidade para o FIV, e o teste ALERE apresentou maior especificidade para o FeLV. Os resultados mostraram uma boa correlação entre os testes.(AU)

FIV and FeLV are Retrovirus associated mainly with feline neoplasms. Two point-of-care tests are commercially available in Brazil for diagnosis of these infections: a bidirectional flow immunochromatography kit (IDEXX SNAP ® Combo) and a lateral unidirectional flow immunochromatography kit (ALERE/BIONOTE Anigen Rapid). The aim of this study was to compare SNAP ® and ALERE tests. Blood samples obtained from 178 cats were evaluated using both tests. Quantitative real-time polymerase chain reaction (qPCR) was used as confirmatory test for all samples. The sensitivity and specificity of SNAP ® test was 100% for FIV, and for ALERE test was 96.15% and 98.68%, respectively. The sensitivity and specificity for FeLV was 93.02% and 96.30% for SNAP ® test and 90.70% and 97.78% for ALERE test. Three samples with a qPCR positive result for FeLV obtained a false negative result in both SNAP ® and ALERE tests. There was no statistically significant difference between the two methods. Considering qPCR as gold standard method, the SNAP® test showed higher sensitivity and specificity for FIV, and the ALERE test presented higher specificity for FeLV. The results showed good agreement among the tests.(AU)

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FIV e FeLV são retrovírus associados principalmente com neoplasias. Dois testes rápidos são disponibilizados no Brasil para o diagnóstico dessas infecções: um kit de imunocromatografia de fluxo bidirecional (SNAP® Combo IDEXX) e um kit de imunocromatografia de fluxo lateral unidirecional (ALERE/BIONOTE Anigen Rapid). O objetivo deste estudo foi comparar o teste SNAP® com o teste ALERE. Amostras de sangue de 178 gatos foram testadas utilizando-se ambos os kits. A reação em cadeia de polimerase em tempo real (qPCR) foi empregada como método confirmatório para todos os resultados. O teste SNAP® apresentou sensibilidade e especificidade de 100% para FIV; a sensibilidade e a especificidade do teste ALERE foram de 96,15% e 98,68%, respectivamente. A sensibilidade e a especificidade para o FeLV foram de 93,02% e 96,30% para o teste SNAP® e de 90,70% e 97,78% para o teste ALERE. Ainda em relação ao FeLV, três amostras com resultado positivo na qPCR obtiveram resultado falso-negativo em ambos os testes. Não houve diferença estatisticamente significante entre os métodos. Considerando a qPCR como padrão-ouro, o teste SNAP® apresentou maior sensibilidade e especificidade para o FIV, e o teste ALERE apresentou maior especificidade para o FeLV. Os resultados mostraram uma boa correlação entre os testes.(AU)

FIV and FeLV are Retrovirus associated mainly with feline neoplasms. Two point-of-care tests are commercially available in Brazil for diagnosis of these infections: a bidirectional flow immunochromatography kit (IDEXX SNAP ® Combo) and a lateral unidirectional flow immunochromatography kit (ALERE/BIONOTE Anigen Rapid). The aim of this study was to compare SNAP ® and ALERE tests. Blood samples obtained from 178 cats were evaluated using both tests. Quantitative real-time polymerase chain reaction (qPCR) was used as confirmatory test for all samples. The sensitivity and specificity of SNAP ® test was 100% for FIV, and for ALERE test was 96.15% and 98.68%, respectively. The sensitivity and specificity for FeLV was 93.02% and 96.30% for SNAP ® test and 90.70% and 97.78% for ALERE test. Three samples with a qPCR positive result for FeLV obtained a false negative result in both SNAP ® and ALERE tests. There was no statistically significant difference between the two methods. Considering qPCR as gold standard method, the SNAP® test showed higher sensitivity and specificity for FIV, and the ALERE test presented higher specificity for FeLV. The results showed good agreement among the tests.(AU)

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Background: Caprine Arthritis Encephalitis (CAE) is a disease that causes productive losses in dairy goat flocks due to thereduction in milk production, followed by lesions in joints and mammary glands. An early diagnosis is essential, consideringthat there is frequent occurrence of asymptomatic animals. Hence, this study aimed to perform a comparison of immunological and molecular based diagnostic tests, represented by Agar Gel Immunodiffusion (AGID), Western Blot (WB) andnested Polymerase Chain Reaction (nPCR). In addition, the mammary glands (MG) of dairy goats were clinically evaluated.Materials, Methods & Results: Blood collection and clinical examination were performed in 1191 dairy goats of 12 farms locatedin Northeastern and Southeastern regions of Brazil. Serological (AGID, WB) and molecular (nPCR) test results were comparedand the data, along with MG alterations, were analyzed using Epi-info 7 and WinEpiscope 2.0. Seroprevalence in AGID test was41.14% (490/1191). In WB, 51.47% (613/1191) of animals were seropositive and nPCR detected 69.44% (827/1191) positiveanimals. Hence, WB was more sensitive (P < 0.001) than AGID. However, nPCR detected more positive animals than AGID (P< 0.001) and WB (P < 0.001). The analysis of mammary glands revealed that 105 out of 1096 nanny goats presented alterations,of which 101 presented altered consistency, 16 presented elevated temperatures and 60 had enlarged retromammary lymph nodes.There was significant statistic difference (P < 0.05) only when comparing the results of serological tests with MG alterations.Discussion: In general, AGID technique is most frequently used when screening flocks for the disease due to the practicalityand low cost this test presents. However, the results demonstrated that AGID detected the lowest number of positive animals.This low sensitivity that the test presented may be attributed to its antigen-antibody interaction mechanism...

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