PESQUISA VETERINÁRIA BRASILEIRA

Abstract in English:

The causes of death of cattle kept in pre-export feedlots (PEFs) and in feedlot for finishing for slaughter are described. Two studies were conducted: a retrospective study of mortality cases in feedlots from 2000 to 2017 registered at the “Laboratório Regional de Diagnóstico” of the “Faculdade de Veterinária” of the “Universidade Federal de Pelotas”; and a prospective study from January 2018 to August 2019, following up 22 feedlots for finishing and six PEFs for the export of live cattle. From January 2000 to August 2019 samples of 150 cases of diseases that affected feedlot cattle were received from 22 feedlots for finishing and 115 of the six PEFs followed. Mortality considering all diagnosed diseases was significantly higher in feedlots for finishing (p<0.05), than in PEFs for the export of live cattle, of 1% and 0.12%, respectively. Diseases of the digestive system were the most important causes, of death in feedlots regardless of its purpose. Acidosis presented the highest mortality rates both in feedlot for finishing (3.33%) as in PEFs for export (0.95%). In all cases the disease occurred due to failure in the adaptation of animals to the ingestion of concentrated foods. Bovine tick fever and pneumonia presented mortality rates of 0.13% and 0.09%, respectively in PEFs. In the feedlot for finishing seneciosis was the second cause of death due to cattle coming from areas with high infestation by the plant. In the present study, it was possible to identify the main diseases that occur in cattle feedlots for finishing or for the export of live animals in the southern region of Rio Grande do Sul. These diseases are known in other systems of cattle breeding and can be prevented or controlled through management, chemoprophylaxis or vaccination, minimizing losses due to mortality.

• Beef cattle feedlot pre-export feedlots acidosis bloat respiratory deseases tick fever cattle

Abstract in Portuguese:

Descrevem-se as causas de morte de bovinos mantidos confinados em estabelecimentos pré-embarque (EPEs) para exportação de animais vivos e em estabelecimentos de terminação para abate. Foram realizados dois estudos: um retrospectivo dos casos de mortalidade em confinamentos de 2000 a 2017 registrados no Laboratório Regional de Diagnóstico da Faculdade de Veterinária da Universidade Federal de Pelotas; e um estudo prospectivo de janeiro de 2018 a agosto de 2019, acompanhando-se 22 confinamentos de terminação e seis EPEs para exportação de bovinos vivos. No total, de janeiro de 2000 a agosto de 2019 foram recebidos no LRD-UFPel amostras de 150 casos de enfermidades que afetaram bovinos confinados, 35 provenientes de 22 confinamentos de terminação e 115 dos seis EPEs acompanhados. A mortalidade considerando-se todas as enfermidades diagnosticadas foi significativamente maior nos confinamentos para terminação (p<0,05), do que nos EPEs para exportação de bovinos vivos, de 1% e 0,12%, respectivamente. As doenças do sistema digestivo foram as causas de morte mais importante nos confinamentos, independente da finalidade. Acidose apresentou as maiores taxas de mortalidade tanto nos confinamentos para terminação (3,33%) como nos EPEs para exportação (0,95%). Em todos os casos a doença ocorreu devido a falha na adaptação dos animais à ingestão de alimentos concentrados. Tristeza parasitária bovina e pneumonias apresentaram taxas de mortalidade de 0,13% e 0,09, respectivamente em EPEs de exportação. Nos confinamentos para terminação a seneciose foi a segunda causa de morte devido aos bovinos serem provenientes de áreas com alta infestação pela planta. Este estudo permitiu identificar as principais enfermidades diagnosticadas em confinamentos para terminação de bovinos ou para exportação de bovinos vivos na região Sul do Rio Grande do Sul. Observou-se que são doenças que ocorrem em outros sistemas de criação de bovinos e que podem ser prevenidas ou controladas por meio de manejo, quimioprofilaxia ou vacinação, minimizando prejuízos por mortalidade de animais.

• Bovinos de corte confinamento estabelecimento pré-embarque acidose timpanismo doenças respiratórias tristeza parasitária

Abstract in English:

This study evaluated the incidence of natural infection by agents of cattle tick fever (CTF), Anaplasma marginale, Babesia bovis and Babesia bigemina in calves born in five farms within the semiarid region of Paraíba state, Brazil. In each farm, blood samples were collected from 6 to 14 calves every 14 days during the first 12 months of life of each animal. Blood samples were processed by microhematocrit and tested by PCR for detection of DNA of A. marginale, B. bovis and B. bigemina. In parallel, the tick infestations on animals were quantified in the five farms, as well as populations in horseflies in three farms. From a total of 41 calves monitored during the first year of life, 25 (61.0%) had positive PCR for A. marginale, 7 (17.1%) for B. bigemina and 3 (7.3%) to B. bovis. Incidence values for A. marginale infection ranged from 83.3% to 100% in four farms. Infection with B. bigemina in calves was detected at only two farms (incidence of 12.5% and 85.7%) and by B. bovis in just one (42.8% incidence). On one farm 14 calves remained negative for A. marginale, B. bigemina and B. bovis during the 12 month follow-up. PCR results were confirmed by DNA sequencing of amplified products. The presence of Rhipicephalus (Boophilus) microplus was found only in two farms in which there was infection by A. marginale, B. bigemina and B. bovis (the latter agent in only one of them). A total of 930 horseflies were captured in the study, most during periods of rain in the region; 70.7% of horseflies corresponded to Tabanus claripennis. There was significant association between a positive PCR for A. marginale and B. bigemina and lower hematocrit values. This study demonstrates that even evaluating only five rural properties, the incidence of CTF occurred heterogeneously in the region, confirming the status of enzootic instability area for CTF, previously reported for the semiarid region of Paraiba.

• Anaplasma marginale Babesia bigemina Babesia bovis calves cattle cattle tick fever ticks hematophagous Diptera Brazil parasitoses

Abstract in Portuguese:

Este estudo avaliou a incidência de infecções naturais pelos agentes da tristeza parasitária bovina (TPB), Anaplasma marginale, Babesia bovis e Babesia bigemina, em bezerros nascidos em cinco fazendas do semiárido paraibano. Em cada fazenda, foram coletadas amostras de sangue de 6 a 14 bezerros a cada 14 dias durante os primeiros 12 meses de vida de cada animal. As amostras de sangue foram processadas por microhematócrito e testadas por PCR para detecção de DNA de A. marginale, B. bovis e B. bigemina. Em paralelo, foram quantificadas as infestações por carrapatos nos bovinos nas cinco fazendas, assim como as populações de tabanídeos em três fazendas. De 41 bezerros monitorados durante o primeiro ano de vida, 25 (61,0%) apresentaram PCR positivo para A. marginale, 7 (17,1%) para B. bigemina e 3 (7,3%) para B. bovis. Os valores de incidência da infecção por A. marginale variaram de 83,3% a 100% em quatro fazendas. A infecção por B. bigemina ocorreu em bezerros de apenas duas fazendas (incidências de 12,5% e 85,7%) e a por B. bovis em apenas uma (incidência de 42,8%). Em uma fazenda os 14 bezerros permaneceram negativos para A. marginale, B. bigemina e B. bovis durante os 12 meses de acompanhamento. Os resultados de PCR foram confirmados por sequenciamento de DNA de produtos amplificados. A presença de carrapatos Rhipicephalus (Boophilus) microplus foi verificada somente em duas propriedades, nas quais houve infecção por A. marginale, B. bigemina e B. bovis (este último agente em apenas uma delas). Foram capturados 930 tabanídeos no estudo, a maioria durante os períodos de chuvas na região; 70,7% dos tabanídeos corresponderam a Tabanus claripennis. Houve associação significativa entre PCR positivo para A. marginale ou B. bigemina e menores valores de hematócrito. Este estudo demonstra que, mesmo avaliando apenas cinco propriedades rurais, a incidência dos agentes da TPB ocorreu de forma heterogênea na região, corroborando o status de área de instabilidade enzoótica para TPB previamente relatado para o semiárido paraibano.

• Anaplasma marginale Babesia bigemina Babesia bovis bezerro bovinos Paraíba tristeza parasitária bovina carrapatos dípteros hematófagos parasitoses

Abstract in English:

Babesiosis is a hemolytic tick-borne disease caused by intraerythrocytic protozoal parasites of the genus Babesia. This is a disease of high incidence in the southern Brazil and responsible for considerable economic losses. Clinical-pathological diagnosis can be made by demonstrating the parasite by examining blood smears or fresh tissues. However, frequently, only formalin-fixed organs are sent to pathology laboratories, which makes it impossible to perform the smears. The main objective of this study was to find alternative histochemical techniques capable to improve the identification of intraerythrocytic Babesia bovis in histological sections. For this study, tissue samples from 50 bovine necropsy cases were retrospectively analyzed, which had been fixed in formalin and routinely processed for histopathology. The cases were divided into a control group, consisting of 12 cases of cerebral babesiosis with characteristic pink-cherry gray matter (group A), and 38 cases suggestive of cattle tick fever (group B), according to necropsy protocols. Histochemical techniques of Alcian Blue, Methylene Blue, Toluidine Blue, Giemsa, Gram (McCallum-Goodpasture method), Grocott, Periodic Acid of Schiff and Ziehl-Neelsen were tested. Among these, it was observed that the techniques of Methylene Blue and Toluidine Blue allowed to observe morphological and dye characteristics in a clearer way, aiding in the identification of B. bovis. In addition, several clinical-epidemiological and anatomopathological parameters of babesiosis caused by B. bovis were established.

• Histochemical diagnosis babesiosis Babesia bovis Methylene Blue Toluidine Blue disease of cattle cattle tick fever parasitoses

Abstract in Portuguese:

A babesiose é uma doença hemolítica transmitida por carrapatos e causada por protozoários intraeritrocitários do gênero Babesia. Esta é uma doença de incidência elevada na Região Sul do Brasil e responsável por perdas econômicas consideráveis. O diagnóstico clínico-patológico pode ser feito através da demonstração do parasito pelo exame de esfregaços sanguíneos ou de tecidos frescos. Entretanto, com frequência, somente órgãos fixados em formol são remetidos para laboratórios de patologia, o que impossibilita a realização do esfregaço. O principal objetivo deste estudo foi encontrar técnicas histoquímicas alternativas e capazes de aprimorar a evidenciação de Babesia bovis intraeritrocitária em tecidos fixados em formol. Para este estudo, foram analisadas retrospectivamente amostras de tecidos de 50 casos de necropsias de bovinos, as quais haviam sido fixadas em formol e processadas rotineiramente para histopatologia. Os casos foram divididos em um grupo controle, constituído por 12 casos de babesiose cerebral com substância cinzenta encefálica róseo-cereja característica (grupo A), e 38 casos sugestivos de tristeza parasitária bovina (grupo B), conforme os protocolos de necropsias. Foram testadas as técnicas histoquímicas de Azul Alciano, Azul de Metileno, Azul de Toluidina, Giemsa, Gram (método de McCallum-Goodpasture), Grocott, Ácido Periódico de Schiff e Ziehl-Neelsen. Dentre estas, observou-se que as técnicas de Azul de Metileno e Azul de Toluidina permitiram observar características morfológicas e tintoriais de maneira mais nítida, auxiliando na identificação de B. bovis. Adicionalmente, foram estabelecidos vários parâmetros clínico-epidemiológicos e anatomopatológicos da babesiose por B. bovis.

• Histoquímica bovinos babesiose Babesia bovis Azul de Metileno Azul de Toluidina doenças de bovinos tristeza parasitária bovina parasitoses

Abstract in English:

This study aimed to determine the seroprevalence of Babesiosis and Anaplasmosis in cattle from the municipalities of Ouricuri and Petrolina, state of Pernambuco, Brazil, and to define the risk factors for the occurrence of the diseases. Blood samples were collected for serologic testing by Indirect Immunofluorescence Assay (IFA). Sanitary epidemiological questionnaires were applied to the producers aiming to identify possible risk factors. Ticks were collected, identified and tested by Polymerase Chain Reaction (PCR) for the diagnosis of infection by Anaplasma marginale, Babesia bigemina and Babesia bovis. The study was conducted with 861 cattle, being 468 in Petrolina and 393 in Ouricuri. The seroprevalence of A. marginale, B. bigemina and B. bovis in Petrolina was of 35.0% (164/468), 35.9% (168/468) and 32.3% (151/468), respectively; and in Ouricuri was 45.5% (179/393), 38.6% (152/393), and 54.9% (216/393), respectively. Co-infection for Anaplasma spp. and Babesia spp. was observed in 31.6% and 32.1% samples of Petrolina and Ouricuri, respectively. The detection of DNA of Babesia spp. by PCR was possible in 5.8% (8/137) ticks; which 62.5% (5/8) was detected later infection with B. bovis; and 23.3% (32/137) with A. marginale. The presence of ticks, the use of acaricide, age, race, and county of residence of the animals were identified as risk factors for TBD by univariate analysis and multivariate. This study allowed the characterization of the municipalities studied as enzootic instability areas for these hemoparasitic, and consequently alert for adoption of adequate control measures and new studies.

• Cattle Tick Fever semi-arid of Pernambuco Babesia bigemina Babesia bovis Anaplasma marginale epidemiology

Abstract in Portuguese:

Este estudo objetivou determinar a soroprevalência da Babesiose e Anaplasmose em bovinos dos municípios de Ouricuri e Petrolina, estado de Pernambuco, Brasil; e definir os possíveis fatores de risco para a ocorrência dessas doenças. Amostras de sangue foram coletadas para realização de teste sorológico por Imunofluorescência Indireta (RIFI). Questionários epidemiológicos sanitários foram aplicados aos produtores com o objetivo de identificar possíveis fatores de risco. Carrapatos foram coletados, identificados e testados por Reação em Cadeia da Polimerase (PCR) para o diagnóstico da infecção por Anaplasma marginale, Babesia bigemina e Babaesia bovis. O estudo foi conduzido com 861 bovinos, sendo 468 de Petrolina e 393 de Ouricuri. A soroprevalência de A. marginale, B. bigemina e B. bovis em Petrolina foi de 35,0% (164/468), 35,9% (168/468) e 32,3% (151/468), respectivamente; e em Ouricuri foi de 45,5% (179/393), 38,6% (152/393) e 54,9% (216/393), respectivamente. A co-infecção por Anaplasma spp. e Babesia spp. foi observada em 31,6% e 32,1% de amostras de Petrolina e Ouricuri, respectivamente. A detecção de DNA de Babesia spp. por PCR foi possível em 5,8% (8/137) carrapatos, dos quais em 62,5 % (5/8) foi detectada posteriormente infecção por B. bovis, e em 23,3% (32/137) por A. marginale. A presença de carrapatos, o uso de acaricidas, idade, raça, e o município de residência dos animais foram identificados como fatores de risco para TPB pela análise univariável e multivariável. Este estudo permitiu caracterizar os municípios estudados como de instabilidade enzoótica para esses hemoparasitos, e consequentemente, alertar para adoção de medidas adequadas de controle e realização de novos estudos.

• Tristeza Parasitária bovinos semiárido pernambucano Babesia bigemina Babesia bovis Anaplasma marginale epidemiologia

Abstract in English:

ABSTRACT.- Costa V.M.M., Rodrigues A.L., Medeiros J.M.A., Labruna M.B., Simões S.V.D. & Riet-Correa F. 2011. [Cattle tick fever in the semiarid region of the Brazilian state of Paraiba.] Tristeza parasitária bovina no Sertão da Paraíba. Pesquisa Veterinária Brasileira 31(3):239-243. Hospital Veterinário, Centro de Saúde e Tecnologia Rural, Universidade Federal de Campina Grande, Campus de Patos, 58700-970 Patos, PB, Brazil. E-mail: valery.medeiros@hotmail.com Twenty four outbreaks of cattle tick fever are reported in the semiarid region of Paraiba known as Sertão. Eighteen outbreaks were caused by Anaplasma. marginale, two by Babesia bigemina, and two by mixed infection of A. marginale and Babesia sp. In other two outbreaks of babesiosis the species of Babesia was not identified. Outbreaks occurred from August 2007 to October 2009, however with a concentration of the outbreaks at the end of the rainy period and beginning of the dry period in each year. Twenty two outbreaks affected adult cattle and two affected calves approximately 11 months-old. Three outbreaks affected Bos taurus indicus cattle, of the Nelore and Gir breeds. In 21 outbreaks Holstein, Brown Swiss and crossbred of these breeds with Bos taurus indicus cattle were affected. It is concluded that in the sertão of Paraíba there are areas of enzootic instability for cattle tick fever occurring outbreaks at the end of the rainy season, mainly in hilly areas of the Borborema region, and in wet areas of some river basins, including Rio do Peixe, Rio Piranhas and Rio Espinharas.

• Anaplasmosis babesiosis tick fever Anaplasmose babesiose tristeza parasitária

Abstract in Portuguese:

RESUMO.- Costa V.M.M., Rodrigues A.L., Medeiros J.M.A., Labruna M.B., Simões S.V.D. & Riet-Correa F. 2011. [Cattle tick fever in the semiarid region of the Brazilian state of Paraiba.] Tristeza parasitária bovina no Sertão da Paraíba. Pesquisa Veterinária Brasileira 31(3):239-243. Hospital Veterinário, Centro de Saúde e Tecnologia Rural, Universidade Federal de Campina Grande, Campus de Patos, 58700-970 Patos, PB, Brazil. E-mail: valery.medeiros@hotmail.com Descrevem-se 24 surtos de tristeza parasitária bovina no sertão paraibano, sendo 18 de anaplasmose por Anaplasma margimale, dois de babesiose por Babesia bigemina, dois por Babesia não identificada e dois por infecção mista de A. marginale e Babesia sp. Os surtos ocorreram entre agosto de 2007 a outubro de 2009, porém, com uma concentração dos surtos no final do período chuvoso e início do período seco de cada ano, sendo 22 em animais adultos e dois em bezerros de aproximadamente 11 meses. Dois surtos ocorreram em bovinos da raça Nelore, um em animais da raça Gir e os 21 restantes ocorreram em animais das raças Holandês, Pardo Suiço e mestiços das mesmas com zebuínos. Conclui-se que no sertão da Paraíba há áreas de instabilidade enzoótica, ocorrendo surtos de tristeza no final da época de chuvas, principalmente nas áreas de planaltos e serras da região da Borborema e em áreas úmidas como a Bacia do Rio do Peixe, Rio Piranhas e Rio Espinharas em que há a formação de microclimas favoráveis à sobrevivência do carrapato.

Abstract in English:

ABSTRACT.- Costa V.M.M., Simões S.V.D. & Riet-Correa F. 2009. [Parasitic diseases in ruminants in the Brazilian semiarid.] Doenças parasitárias em ruminantes no semi-árido brasileiro. Pesquisa Veterinária Brasileira 29(7):563-568. Hospital Veterinário, CSTR, Universidade Federal de Campina Grande, Campus de Patos, 58700-970 Patos, PB, Brazil. Email: franklin.riet@pq.cnpq.br Clinical cases and diagnostic specimens from ruminants received by the Veterinary Hospital of the University of Campina Grande in Patos, Paraíba, Brazil, from January 2000 to August 2007, were reviewed to evaluate some epidemiological aspects of parasitic diseases of ruminants in the semiarid region of Paraíba and neighboring states. The region has an annual rainfall of about 800mm, with irregular rains concentrated in a 3 to 4-month-period, and an average annual temperature of 26°C. During those years, 163 (5.31%) out of 3,064 ruminants were affected by some parasitic disease. The most important parasitosis in goats and sheep was gastrointestinal helminthiasis, mainly hemonchosis; goats were more affected (6.24% of cases in this species) than sheep (4.7% of cases). The higher frequency of the disease in goats may be associated with higher susceptibility or due to treatment mistakes, i.e. use of the same dose for both species, which for most anti-antihelmintics is insufficient for goats. Cattle have a low rate of gastrointestinal helminthiasis (1 out of 1,113 cases). This low frequency is probably due to the farming system in the semiarid, with low stocking rate, up to one adult bovine for every 13-16 ha, and permanence of calves (susceptible) with their mothers (resistant) for nearly one year before weaning. The occurrence of eimeriosis in goats and sheep was observed in 0.76% of the cases, involving only young animals. The main cattle disease was tick fever with 14 outbreaks. Outbreaks of tick fever occur, mainly at the end of the raining season in areas of the semiarid which are marginal for tick, like plateaus and mountains of the Borborema region, irrigated areas, and areas of the basins of two rivers of the region. In the drier areas of the semiarid Rhipicephalus (Boophilus) microplus do not survive during the dry period, but tick fever can occur when cattle with ticks are introduced at the onset of the raining season.

• Ruminant; parasitic diseases helminthiasis parasitosis tick fever

Abstract in Portuguese:

ABSTRACT.- Costa V.M.M., Simões S.V.D. & Riet-Correa F. 2009. [Parasitic diseases in ruminants in the Brazilian semiarid.] Doenças parasitárias em ruminantes no semi-árido brasileiro. Pesquisa Veterinária Brasileira 29(7):563-568. Hospital Veterinário, CSTR, Universidade Federal de Campina Grande, Campus de Patos, 58700-970 Patos, PB, Brazil. Email: franklin.riet@pq.cnpq.br Clinical cases and diagnostic specimens from ruminants received by the Veterinary Hospital of the University of Campina Grande in Patos, Paraíba, Brazil, from January 2000 to August 2007, were reviewed to evaluate some epidemiological aspects of parasitic diseases of ruminants in the semiarid region of Paraíba and neighboring states. The region has an annual rainfall of about 800mm, with irregular rains concentrated in a 3 to 4-month-period, and an average annual temperature of 26°C. During those years, 163 (5.31%) out of 3,064 ruminants were affected by some parasitic disease. The most important parasitosis in goats and sheep was gastrointestinal helminthiasis, mainly hemonchosis; goats were more affected (6.24% of cases in this species) than sheep (4.7% of cases). The higher frequency of the disease in goats may be associated with higher susceptibility or due to treatment mistakes, i.e. use of the same dose for both species, which for most anti-antihelmintics is insufficient for goats. Cattle have a low rate of gastrointestinal helminthiasis (1 out of 1,113 cases). This low frequency is probably due to the farming system in the semiarid, with low stocking rate, up to one adult bovine for every 13-16 ha, and permanence of calves (susceptible) with their mothers (resistant) for nearly one year before weaning. The occurrence of eimeriosis in goats and sheep was observed in 0.76% of the cases, involving only young animals. The main cattle disease was tick fever with 14 outbreaks. Outbreaks of tick fever occur, mainly at the end of the raining season in areas of the semiarid which are marginal for tick, like plateaus and mountains of the Borborema region, irrigated areas, and areas of the basins of two rivers of the region. In the drier areas of the semiarid Rhipicephalus (Boophilus) microplus do not survive during the dry period, but tick fever can occur when cattle with ticks are introduced at the onset of the raining season.

Abstract in English:

ABSTRACT.- Almeida M.B., Tortelli F.P., Riet-Correa B., Ferreira J.L.M., Soares M.P., Farias N.A.R., Riet-Correa F. & Schild A.L. 2006. [Tick fever in southern Brazil: a retrospective study of 1978-2005.] Tristeza parasitária bovina na região sul do Rio Grande do Sul: estudo retrospectivo de 1978-2005. Pesquisa Veterinária Brasileira 26(4):236-242. Laboratório Regional de Diagnóstico, Faculdade de Veterinária, Universidade Federal de Pelotas, Campus Universitário s/n, Pelotas, RS 96010-900, Brazil. E-mail: alschild@terra.com.br A retrospective study of tick fever was made, which occurred from 1978-2005 in southern Rio Grande do Sul in the influence area of the Regional Diagnostic Laboratory of the Federal University of Pelotas. From 4,884 cattle specimens, sent by practitioners or which were from necropsies performed at the Diagnostic Laboratory, 231 (4.7%) were diagnosed as tick fever. Data from 221 of those outbreaks were analyzed. Ninety one (41.1%) outbreaks were caused by Babesia bovis, 11 (4.9%) by Babesia bigemina, and 65 (29.41%) by Anaplasma marginale. In other 33 (14.93%) outbreaks of babesiosis there is no information if the disease was caused by B. bovis or B. bigemina, and 21 (9.5%) outbreaks were caused by mixed infection of A. marginale and B. bovis or B. bigemina. Mean morbidity, mortality, and letality rates in 149 outbreaks were 11.17%, 6.81%, and 70.04%, respectively. Most outbreaks occurred during summer (January-March) and autumn (April-June), mainly in 1 to 3-year-old cattle. Clinical signs were depression, weakness, fallen ears, fever, and weight loss. Low packed cell volume values were always found. Hemoglobinury was observed in babesiosis. Neurological signs characterized by gait alterations, muscular tremors, aggressiveness and falling down with tonic and clonic convulsions were observed in babesiosis by B. bovis. The main gross lesions were anemia, jaundice, splenomegaly, hepatomegaly, yellow liver and cardiac hemorrhages. Hemoglobinury was observed in babesiosis, and congestion of the cerebral cortex in babesiosis by B. bovis. It is concluded that B. bovis is the main agent causing thick fever in southern Rio Grande do Sul. In that region with a cattle population of 2,630,000 heads the annual losses due to tick fever can be estimated in 6,220 cattle or US$ 1,623,000.00. Preventive measures to diminish tick fever losses in the region are necessary.

• Parasitic diseases tick fever epidemiology Babesia bovis Babesia bigemina Anaplasma marginale

Abstract in Portuguese:

ABSTRACT.- Almeida M.B., Tortelli F.P., Riet-Correa B., Ferreira J.L.M., Soares M.P., Farias N.A.R., Riet-Correa F. & Schild A.L. 2006. [Tick fever in southern Brazil: a retrospective study of 1978-2005.] Tristeza parasitária bovina na região sul do Rio Grande do Sul: estudo retrospectivo de 1978-2005. Pesquisa Veterinária Brasileira 26(4):236-242. Laboratório Regional de Diagnóstico, Faculdade de Veterinária, Universidade Federal de Pelotas, Campus Universitário s/n, Pelotas, RS 96010-900, Brazil. E-mail: alschild@terra.com.br A retrospective study of tick fever was made, which occurred from 1978-2005 in southern Rio Grande do Sul in the influence area of the Regional Diagnostic Laboratory of the Federal University of Pelotas. From 4,884 cattle specimens, sent by practitioners or which were from necropsies performed at the Diagnostic Laboratory, 231 (4.7%) were diagnosed as tick fever. Data from 221 of those outbreaks were analyzed. Ninety one (41.1%) outbreaks were caused by Babesia bovis, 11 (4.9%) by Babesia bigemina, and 65 (29.41%) by Anaplasma marginale. In other 33 (14.93%) outbreaks of babesiosis there is no information if the disease was caused by B. bovis or B. bigemina, and 21 (9.5%) outbreaks were caused by mixed infection of A. marginale and B. bovis or B. bigemina. Mean morbidity, mortality, and letality rates in 149 outbreaks were 11.17%, 6.81%, and 70.04%, respectively. Most outbreaks occurred during summer (January-March) and autumn (April-June), mainly in 1 to 3-year-old cattle. Clinical signs were depression, weakness, fallen ears, fever, and weight loss. Low packed cell volume values were always found. Hemoglobinury was observed in babesiosis. Neurological signs characterized by gait alterations, muscular tremors, aggressiveness and falling down with tonic and clonic convulsions were observed in babesiosis by B. bovis. The main gross lesions were anemia, jaundice, splenomegaly, hepatomegaly, yellow liver and cardiac hemorrhages. Hemoglobinury was observed in babesiosis, and congestion of the cerebral cortex in babesiosis by B. bovis. It is concluded that B. bovis is the main agent causing thick fever in southern Rio Grande do Sul. In that region with a cattle population of 2,630,000 heads the annual losses due to tick fever can be estimated in 6,220 cattle or US$ 1,623,000.00. Preventive measures to diminish tick fever losses in the region are necessary.