Esta pesquisa investigou como os Cursos Superiores de Medicina Veterinária no Brasil (CSMV) estão oferecendo conhecimentos relacionados à "Extensão Rural". Foram aplicados questionários aos 149 cursos de Medicina Veterinária em funcionamento. Deste universo, obteve-se uma amostra de 57 entrevistados que responderam à pesquisa (38,3%). Em que pesem as mudanças curriculares após o Parecer 105/2002, a disciplina ainda é oferecida na maioria (97%) dos cursos, evidenciando o reconhecimento de sua importância na formação dos alunos de graduação. Três aspectos observados merecem reflexão: a heterogeneidade na carga horária da disciplina, variando de 30 a 90 horas/semestre; certa heterogeneidade da inserção (semestre/período) na grade, podendo constar desde o segundo até o último período; e a ampla gama de temas que constam nos programas. Sugere-se que os programas da disciplina de Extensão Rural, a serem oferecidos nos CSMV, procurem inserir três pontos que se entende serem importantes, mas nem sempre abordados: i) a "extensão rural" com seus múltiplos enfoques (serviço público para o desenvolvimento holístico das famílias rurais, assistência técnica propriamente dita, difusão de tecnologia, prática pedagógica, processo de comunicação etc.); ii) temas relacionados diretamente à atuação do médico veterinário (tais como a relação da extensão com a sanidade animal e humana, a defesa agropecuária etc.); e iii) temas emergentes relacionados a áreas multidisciplinares, especialmente a sustentabilidade, o meio ambiente e o bem-estar animal. | This research investigates how the Undergraduate Courses of Medicine Veterinary currently provide knowledge regarding "Rural Extension". It was applied questionnaires to the 149 courses in activity, out of which 57 answered the survey (38.3%). Despite the curricular changes proposed by the government in 2002, the discipline is still offered in the majority of the schools (97%), showing the recognition of its importance in the undergraduate student education. Three central aspects needs attention: the heterogeneity regarding the hours of the discipline, ranging from 30 to 90 hours per semester; a relative heterogeneity where the discipline is inserted in the curriculum, ranging from the second to the last semester; and the wide range of issues presented in the discipline's programs. It's suggested that the programs should try to include three sets of knowledge that are considered important to professionals of the future, and that appeared with little relevance in current programs: i) an extension with its multiple focus; ii) issues directly related to the veterinary actuation; and iii) emerging issues related to multidisciplinary areas, specially sustainability, the human-animal relation and the animal welfare.

Esta pesquisa investigou como os Cursos Superiores de Medicina Veterinária no Brasil (CSMV) estão oferecendo conhecimentos relacionados à "Extensão Rural". Foram aplicados questionários aos 149 cursos de Medicina Veterinária em funcionamento. Deste universo, obteve-se uma amostra de 57 entrevistados que responderam à pesquisa (38,3%). Em que pesem as mudanças curriculares após o Parecer 105/2002, a disciplina ainda é oferecida na maioria (97%) dos cursos, evidenciando o reconhecimento de sua importância na formação dos alunos de graduação. Três aspectos observados merecem reflexão: a heterogeneidade na carga horária da disciplina, variando de 30 a 90 horas/semestre; certa heterogeneidade da inserção (semestre/período) na grade, podendo constar desde o segundo até o último período; e a ampla gama de temas que constam nos programas. Sugere-se que os programas da disciplina de Extensão Rural, a serem oferecidos nos CSMV, procurem inserir três pontos que se entende serem importantes, mas nem sempre abordados: i) a "extensão rural" com seus múltiplos enfoques (serviço público para o desenvolvimento holístico das famílias rurais, assistência técnica propriamente dita, difusão de tecnologia, prática pedagógica, processo de comunicação etc.); ii) temas relacionados diretamente à atuação do médico veterinário (tais como a relação da extensão com a sanidade animal e humana, a defesa agropecuária etc.); e iii) temas emergentes relacionados a áreas multidisciplinares, especialmente a sustentabilidade, o meio ambiente e o bem-estar animal.

Foram revisados os dados de 138 equinos com laminite, atendidos no período de dez anos. Destes, 48 casos de laminite crônica foram selecionados com o objetivo de relacionar a recuperação clínica dos cavalos com a utilização de dois métodos diferentes de distribuição de apoio sobre os cascos: palmilha de isopor e palmilha de isopor associada ao ferrageamento. Os cavalos foram divididos de acordo com a recuperação clínica, método de distribuição de apoio escolhido e grau de rotação da terceira falange. Também foi estabelecido o tempo médio de tratamento. Considerando os graus de rotação 3 a 5, 6 a 8, 9 a 11 e acima de 11, e comparados os dois métodos de distribuição de apoio sobre os cascos, não foi observada diferença estatística na porcentagem de animais com recuperação clínica. Contudo, dos animais que utilizaram palmilha de isopor, 43,5 ± 14% recuperaram-se clinicamente, e nos que utilizaram palmilha de isopor associada ao ferrageamento, obteve-se 69,5 ± 19% de recuperação clínica. Não houve correlação entre o aumento do grau de rotação da terceira falange e tempo de tratamento. Também a recuperação clínica dos animais não teve relação com tempo de tratamento. A literatura correlaciona vários fatores ao prognóstico, porém, neste trabalho demonstrou-se que a o retorno à função anteriormente exercida pelo cavalo não está relacionado ao tempo de tratamento, contudo, sofre influência da utilização do método de ferrageamento. | Data from 138 horses with laminitis treated in the period of ten years were reviewed. Of these, 48 cases of chronic laminitis were selected in order to relate the clinical recovery of horses using two different methods of distribution of body weight on the hooves: foam pad and foam pad associated with shoeing. The horses were divided according to clinical recovery, the weight distribution method chosen and degree of rotation of the third phalange. Also the average time of treatment was established. Considering the degrees of rotation 3-5, 6-8, 9-11 and above 11, and comparing the two methods of distribution of body weight on the hooves, there was no statistical difference in the percentage of animals with clinical recovery. However, 43.5 ± 14% of horses that used foam pad and 69,5 ± 19% of them that used foam pad associated with shoeing recovered clinically. There was no correlation between the increase of the degree of rotation of the third phalanx and treatment time. Clinical recovery of animals was not related to treatment time. Several factors are correlated with prognosis in the literature, but this study demonstrated that the return of the function previously performed by the horse is not related to treatment time, however, is influenced by the use of shoeing.

Foram revisados os dados de 138 equinos com laminite, atendidos no período de dez anos. Destes, 48 casos de laminite crônica foram selecionados com o objetivo de relacionar a recuperação clínica dos cavalos com a utilização de dois métodos diferentes de distribuição de apoio sobre os cascos: palmilha de isopor e palmilha de isopor associada ao ferrageamento. Os cavalos foram divididos de acordo com a recuperação clínica, método de distribuição de apoio escolhido e grau de rotação da terceira falange. Também foi estabelecido o tempo médio de tratamento. Considerando os graus de rotação 3 a 5, 6 a 8, 9 a 11 e acima de 11, e comparados os dois métodos de distribuição de apoio sobre os cascos, não foi observada diferença estatística na porcentagem de animais com recuperação clínica. Contudo, dos animais que utilizaram palmilha de isopor, 43,5 ± 14% recuperaram-se clinicamente, e nos que utilizaram palmilha de isopor associada ao ferrageamento, obteve-se 69,5 ± 19% de recuperação clínica. Não houve correlação entre o aumento do grau de rotação da terceira falange e tempo de tratamento. Também a recuperação clínica dos animais não teve relação com tempo de tratamento. A literatura correlaciona vários fatores ao prognóstico, porém, neste trabalho demonstrou-se que a o retorno à função anteriormente exercida pelo cavalo não está relacionado ao tempo de tratamento, contudo, sofre influência da utilização do método de ferrageamento.

A imunodeficiência viral felina e a leucemia viral felina representam importantes doenças infecciosas causadas por retrovírus. O presente estudo teve por objetivos investigar a sorofrequência da infecção pelo vírus da imunodeficiência felina (FIV) e pelo vírus da leucemia felina (FeLV) em gatos provenientes do município de Araçatuba, Estado de São Paulo. Amostras de sangue de 302 gatos foram colhidas e testadas quanto à presença de anticorpos antivírus da imunodeficiência felina e do antígeno do vírus da leucemia felina por meio do ELISA Snap-Combo®FIV-FeLV (IDEXX Laboratories). A frequência de positividade para FIV foi de 5,63% (17/302) e para FeLV de 0,33% (1/302). Dos 17 gatos infectados pelo FIV, nove (52,94%) eram sintomáticos. Houve um predomínio da infecção pelo FIV em machos (p = 0,0316) e em gatos com idade variando entre um e três anos (p = 0,0324). | Feline immunodeficiency virus and feline leukemia represent important infectious diseases caused by retroviruses. This study aimed to investigate the prevalence of infection by feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) in cats from the municipality of Araçatuba, São Paulo. Blood samples from 302 cats were collected and tested for the presence of antibodies against feline immunodeficiency virus and antigen of feline leukemia virus by ELISA ® Snap-Combo FIV-FeLV (IDEXX Laboratories). The frequency of FIV positivity was 5.63% (17/302) and of FeLV was 0.33% (1/302). Of the 17 cats infected with FIV, nine (52.94%) were symptomatic. There was a prevalence of FIV infection in males (p = 0.0316) and cats aged between one and three years (p = 0.0324).

A imunodeficiência viral felina e a leucemia viral felina representam importantes doenças infecciosas causadas por retrovírus. O presente estudo teve por objetivos investigar a sorofrequência da infecção pelo vírus da imunodeficiência felina (FIV) e pelo vírus da leucemia felina (FeLV) em gatos provenientes do município de Araçatuba, Estado de São Paulo. Amostras de sangue de 302 gatos foram colhidas e testadas quanto à presença de anticorpos antivírus da imunodeficiência felina e do antígeno do vírus da leucemia felina por meio do ELISA Snap-Combo®FIV-FeLV (IDEXX Laboratories). A frequência de positividade para FIV foi de 5,63% (17/302) e para FeLV de 0,33% (1/302). Dos 17 gatos infectados pelo FIV, nove (52,94%) eram sintomáticos. Houve um predomínio da infecção pelo FIV em machos (p = 0,0316) e em gatos com idade variando entre um e três anos (p = 0,0324).

Intestinal contents were collected from eight impala at three different localities during the winter hunting season (2005–2009), as well as from another 24 animals from a one-year trial at a game farm called Ditholo (2003–2004). Gas production, protozoa counts and several other physiological parameters were measured from both rumen and caecum or colon contents. Only higher ophryoscolecid and Isotrichidae species of protozoa were counted and identified. Ostracodinium gracile was present in all 32 impala. Eudiplodinium maggii was present in 31 animals and Eudiplodinium impalae and Epidinium (either ecaudatum or caudatum) in 30 animals. Dasytricha ruminantium was present in only 11 of the impala. Concentrations of protozoa were correlated with the season of sample collection and highly correlated with the animals living on the game farm. Gas production (mL/g of wet rumen ingesta) was weakly correlated with protozoa concentration but not with the season of collection.

Intestinal contents were collected from eight impala at three different localities during the winter hunting season (2005–2009), as well as from another 24 animals from a one-year trial at a game farm called Ditholo (2003–2004). Gas production, protozoa counts and several other physiological parameters were measured from both rumen and caecum or colon contents. Only higher ophryoscolecid and Isotrichidae species of protozoa were counted and identified. Ostracodinium gracile was present in all 32 impala. Eudiplodinium maggii was present in 31 animals and Eudiplodinium impalae and Epidinium (either ecaudatum or caudatum) in 30 animals. Dasytricha ruminantium was present in only 11 of the impala. Concentrations of protozoa were correlated with the season of sample collection and highly correlated with the animals living on the game farm. Gas production (mL/g of wet rumen ingesta) was weakly correlated with protozoa concentration but not with the season of collection.

Ticks, as vectors of disease and damage agents, impact directly and indirectly on the economy of the livestock industry in southern Africa. This study surveyed the occurrence and distribution of ticks infesting livestock across the North West province, South Africa. During three phases in consecutive years, officers of the provincial Veterinary Department collected specimens monthly from livestock hosts at specified sites across the province. Data analysis constituted the fourth phase of the study. A total of 1090 collections from 265 sites yielded 42 566 tick specimens, comprising 22 different tick species (18 ixodids, 4 argasids). The specimens represent all of the major tick vectors of disease that occur in South Africa. The major tick-borne diseases (i.e. heartwater, both African and Asiatic bovine babesiosis and anaplasmosis) were found to be prevalent mainly in the north-eastern region of the province, which also displayed the highest tick species diversity. The central region appears transitory to some of the major vectors. Although some tick species were contained within specific regions, others were widespread across the province. Associated serology data show that most herds sampled in areas endemic for babesiosis and anaplasmosis in the north-eastern region are endemically unstable and at risk to these tick-borne diseases should vector control measures become ineffective.

Ticks, as vectors of disease and damage agents, impact directly and indirectly on the economy of the livestock industry in southern Africa. This study surveyed the occurrence and distribution of ticks infesting livestock across the North West province, South Africa. During three phases in consecutive years, officers of the provincial Veterinary Department collected specimens monthly from livestock hosts at specified sites across the province. Data analysis constituted the fourth phase of the study. A total of 1090 collections from 265 sites yielded 42 566 tick specimens, comprising 22 different tick species (18 ixodids, 4 argasids). The specimens represent all of the major tick vectors of disease that occur in South Africa. The major tick-borne diseases (i.e. heartwater, both African and Asiatic bovine babesiosis and anaplasmosis) were found to be prevalent mainly in the north-eastern region of the province, which also displayed the highest tick species diversity. The central region appears transitory to some of the major vectors. Although some tick species were contained within specific regions, others were widespread across the province. Associated serology data show that most herds sampled in areas endemic for babesiosis and anaplasmosis in the north-eastern region are endemically unstable and at risk to these tick-borne diseases should vector control measures become ineffective.

The dairy industry is a large and important business in Saudi Arabia. Although farms are administered to high international standards, some reproduction problems, of uncertain aetiology, are encountered. The most frequently seen are conception failures, abortions, stillbirths and the birth of weak or malformed calves. These conditions are suggestive of bovine viral diarrhoea virus (BVDV) infection. Unfortunately, very little published information is available regarding the impact of this disease on cattle populations in Saudi Arabia. As a consequence, the present study was carried out and is the first of its kind in Saudi Arabia and the Gulf region. The aim of the study was to elucidate the role of in utero BVDV infection leading to the birth of weak or malformed calves on a large dairy farm in Saudi Arabia. The study was divided into two parts. Firstly, apparently healthy neonatal calves were sampled for the detection of pre-colostral serum antibodies to BVDV. The presence of these antibodies indicates exposure of the foetus to BVDV during the last two trimesters of gestation. Secondly, tissue samples from malformed neonatal calves were examined for the presence of BVDV antigens. Detection of such antigens confirms exposure of the foetus to the virus during the first trimester of gestation. The results of the investigation indicated that 36.1% of the neonatal calves were exposed to BVDV infection in utero. This is higher than what has been reported in the literature and suggests that dairy farmers in the Arabian Peninsula need to be made aware of the dangers of BVDV infections in their herds. The epidemiological significance of the results is discussed.

The dairy industry is a large and important business in Saudi Arabia. Although farms are administered to high international standards, some reproduction problems, of uncertain aetiology, are encountered. The most frequently seen are conception failures, abortions, stillbirths and the birth of weak or malformed calves. These conditions are suggestive of bovine viral diarrhoea virus (BVDV) infection. Unfortunately, very little published information is available regarding the impact of this disease on cattle populations in Saudi Arabia. As a consequence, the present study was carried out and is the first of its kind in Saudi Arabia and the Gulf region. The aim of the study was to elucidate the role of in utero BVDV infection leading to the birth of weak or malformed calves on a large dairy farm in Saudi Arabia. The study was divided into two parts. Firstly, apparently healthy neonatal calves were sampled for the detection of pre-colostral serum antibodies to BVDV. The presence of these antibodies indicates exposure of the foetus to BVDV during the last two trimesters of gestation. Secondly, tissue samples from malformed neonatal calves were examined for the presence of BVDV antigens. Detection of such antigens confirms exposure of the foetus to the virus during the first trimester of gestation. The results of the investigation indicated that 36.1% of the neonatal calves were exposed to BVDV infection in utero. This is higher than what has been reported in the literature and suggests that dairy farmers in the Arabian Peninsula need to be made aware of the dangers of BVDV infections in their herds. The epidemiological significance of the results is discussed.

This study investigated the prevalence, risk factors and species composition of ticks, fleas and lice infesting dogs and cats in and around Hawassa in southern Ethiopia. In total, 200 dogs and 100 cats were examined from November 2008 to April 2009. Of the dogs and cats examined, 99.5% and 91.5%, respectively, were infested with one or more species of ticks, fleas or lice. The overall prevalence was higher in dogs than in cats. A total of six different species of ectoparasites were collected and identified from dogs, but only three species from cats. Ctenocephalides felis was the predominant species amongst the animals, with a prevalence of 82.9% on dogs and 67% on cats. Other prevalent species on dogs included Ctenocephalides canis (73.8%), Heterodoxus spiniger (4%), nymphs of Amblyomma spp. (3.5%), Pulex irritans (2.5%) and Haemaphysalis leachi (0.5%). C. canis (18%) and P. irritans (6%) were also found on cats. More female than male fleas and lice were observed. The study revealed that the prevalence of fleas, ticks and lice on dogs was not significantly different between male and female animals or between young and adult dogs. However, the prevalence of these ectoparasites was significantly higher in female than in male and in adult than in young cats. The study showed that the prevalence of ectoparasites on both dogs and cats was significantly higher on animals with flea allergy dermatitis (FAD) than those without FAD, and on animals with lesions on their skin compared with those without lesions.

This study investigated the prevalence, risk factors and species composition of ticks, fleas and lice infesting dogs and cats in and around Hawassa in southern Ethiopia. In total, 200 dogs and 100 cats were examined from November 2008 to April 2009. Of the dogs and cats examined, 99.5% and 91.5%, respectively, were infested with one or more species of ticks, fleas or lice. The overall prevalence was higher in dogs than in cats. A total of six different species of ectoparasites were collected and identified from dogs, but only three species from cats. Ctenocephalides felis was the predominant species amongst the animals, with a prevalence of 82.9% on dogs and 67% on cats. Other prevalent species on dogs included Ctenocephalides canis (73.8%), Heterodoxus spiniger (4%), nymphs of Amblyomma spp. (3.5%), Pulex irritans (2.5%) and Haemaphysalis leachi (0.5%). C. canis (18%) and P. irritans (6%) were also found on cats. More female than male fleas and lice were observed. The study revealed that the prevalence of fleas, ticks and lice on dogs was not significantly different between male and female animals or between young and adult dogs. However, the prevalence of these ectoparasites was significantly higher in female than in male and in adult than in young cats. The study showed that the prevalence of ectoparasites on both dogs and cats was significantly higher on animals with flea allergy dermatitis (FAD) than those without FAD, and on animals with lesions on their skin compared with those without lesions.

Injury due to burning is known to impact on coagulation and haemostasis by disturbing the coagulation cascade and is also associated with impaired fibrinolysis. Also, venous thrombosis, pulmonary embolism and hypercoagulability are common during thermal injury. Using a Wistar albino rat model, we investigated in this study whether burn injury affects the ultrastructure of the fibrin networks. A typical fibrin network will contain mostly major, thick fibres with minor, thin fibres distributed amongst them. We found that the clot architecture changes after burn injury, showing more prominent minor, thin fibres in a netted appearance. Also, the clot showed areas of matted fibrin. We suggest that the thrombotic events associated with burn injury are due to the thickened and netlike areas formed when thrombin activates the coagulation cascade. This is due to impaired fibrinolysis activities, causing the resulting fibrin clots not to be successfully disseminated. Small fragments of these netted, clumped areas may therefore break loose and lead to thrombotic events after burn injuries. The current study therefore provided morphological evidence for thrombotic events associated with burn injury.

Injury due to burning is known to impact on coagulation and haemostasis by disturbing the coagulation cascade and is also associated with impaired fibrinolysis. Also, venous thrombosis, pulmonary embolism and hypercoagulability are common during thermal injury. Using a Wistar albino rat model, we investigated in this study whether burn injury affects the ultrastructure of the fibrin networks. A typical fibrin network will contain mostly major, thick fibres with minor, thin fibres distributed amongst them. We found that the clot architecture changes after burn injury, showing more prominent minor, thin fibres in a netted appearance. Also, the clot showed areas of matted fibrin. We suggest that the thrombotic events associated with burn injury are due to the thickened and netlike areas formed when thrombin activates the coagulation cascade. This is due to impaired fibrinolysis activities, causing the resulting fibrin clots not to be successfully disseminated. Small fragments of these netted, clumped areas may therefore break loose and lead to thrombotic events after burn injuries. The current study therefore provided morphological evidence for thrombotic events associated with burn injury.

Many studies on the population dynamics of questing ticks on pastures and of parasitic ticks on cattle have been conducted. Few, however, have attempted to link the two in a single study. This study aimed to assess the population dynamics of questing ixodid ticks on pastures and of adult ticks on two breeds of cattle with different levels of susceptibility to tick infestation on the same pastures. Between January 2005 and December 2009 questing ixodid ticks were collected monthly from natural pastures at the Döhne Agricultural Development Institute and at the adjacent Campagna Production System in the Amahlathi District, Eastern Cape province, South Africa. Between February 2007 and January 2010 adult ticks were collected monthly from Bonsmara and Nguni cattle grazing these pastures. Ten tick species were collected from the pastures and 12 from the cattle. Significantly more questing larvae of Rhipicephalus appendiculatus, Rhipicephalus decoloratus, Rhipicephalus evertsi evertsi and Rhipicephalus microplus were recovered from the pastures grazed by Bonsmara cattle than from those grazed by Nguni cattle (p ≤ 0.05). Significantly more adult Hyalomma rufipes, Rhipicephalus follis, R. appendiculatus, R. decoloratus, R. evertsi evertsi and R. microplus were collected from the Bonsmara cattle than from the Nguni cattle (p ≤ 0.05). The study showed that Nguni cattle are less susceptible to tick infestation than are Bonsmara cattle and fewer questing ticks are collected from pastures grazed by Nguni cattle than by Bonsmara cattle.

Many studies on the population dynamics of questing ticks on pastures and of parasitic ticks on cattle have been conducted. Few, however, have attempted to link the two in a single study. This study aimed to assess the population dynamics of questing ixodid ticks on pastures and of adult ticks on two breeds of cattle with different levels of susceptibility to tick infestation on the same pastures. Between January 2005 and December 2009 questing ixodid ticks were collected monthly from natural pastures at the Döhne Agricultural Development Institute and at the adjacent Campagna Production System in the Amahlathi District, Eastern Cape province, South Africa. Between February 2007 and January 2010 adult ticks were collected monthly from Bonsmara and Nguni cattle grazing these pastures. Ten tick species were collected from the pastures and 12 from the cattle. Significantly more questing larvae of Rhipicephalus appendiculatus, Rhipicephalus decoloratus, Rhipicephalus evertsi evertsi and Rhipicephalus microplus were recovered from the pastures grazed by Bonsmara cattle than from those grazed by Nguni cattle (p ≤ 0.05). Significantly more adult Hyalomma rufipes, Rhipicephalus follis, R. appendiculatus, R. decoloratus, R. evertsi evertsi and R. microplus were collected from the Bonsmara cattle than from the Nguni cattle (p ≤ 0.05). The study showed that Nguni cattle are less susceptible to tick infestation than are Bonsmara cattle and fewer questing ticks are collected from pastures grazed by Nguni cattle than by Bonsmara cattle.

Bovine viral diarrhoea virus (BVDV) infection is an important viral infection affecting the cattle industry today. The prevalence of this infection in South African feedlots is unknown. Ear notch biopsies were collected from chronic poor doers and animals that appeared unthrifty upon entering feedlots, as well as animals entering the hospital pen with respiratory disease for the first time. A total of 1690 samples were collected: 1074 from the former category and 616 from the latter. A routine immunohistochemistry staining protocol showed that 49 animals tested positive, of which 43 (4%) came from the feedlot entry group and six (1%) from the hospitalised group. The prevalence of persistently infected cattle from this selected, nonrandom sample entering six large South African feedlots was found to be 2.9%, which is higher than the international rule of thumb that 0.5% of all cattle entering feedlots are persistently infected. There was no clear correlation between persistent infection and respiratory disease. Serum samples were also collected when possible and 10 positive cases were found. Results from enzyme-linked immunosorbent assays for antigen and antibody performed on these sera correlated well with those from the immunohistochemistry staining method in six cases, but in four cases the animals tested falsely positive owing to nonspecific staining. Immunohistochemistry staining on ear notch biopsies is thus a reliable diagnostic method to identify persistently infected animals with BVDV, but the pathologist should be aware of nonspecific positive staining.

Bovine viral diarrhoea virus (BVDV) infection is an important viral infection affecting the cattle industry today. The prevalence of this infection in South African feedlots is unknown. Ear notch biopsies were collected from chronic poor doers and animals that appeared unthrifty upon entering feedlots, as well as animals entering the hospital pen with respiratory disease for the first time. A total of 1690 samples were collected: 1074 from the former category and 616 from the latter. A routine immunohistochemistry staining protocol showed that 49 animals tested positive, of which 43 (4%) came from the feedlot entry group and six (1%) from the hospitalised group. The prevalence of persistently infected cattle from this selected, nonrandom sample entering six large South African feedlots was found to be 2.9%, which is higher than the international rule of thumb that 0.5% of all cattle entering feedlots are persistently infected. There was no clear correlation between persistent infection and respiratory disease. Serum samples were also collected when possible and 10 positive cases were found. Results from enzyme-linked immunosorbent assays for antigen and antibody performed on these sera correlated well with those from the immunohistochemistry staining method in six cases, but in four cases the animals tested falsely positive owing to nonspecific staining. Immunohistochemistry staining on ear notch biopsies is thus a reliable diagnostic method to identify persistently infected animals with BVDV, but the pathologist should be aware of nonspecific positive staining.