Balantidium coli in Pigs of Distinct Animal Husbandry Categories and Different Hygienic-Sanitary Standards in the Central Region of Rio Grande do Sul State, Brazil

Background: Balantidium coli is a commensal protozoan that infects several animals, but it has pigs as its natural reservoir. In the presence of predisposing factors, B. coli can become pathogenic for swine, causing enteric lesions. Infections determined by this protozoan may be a risk to public health, due to dysentery in animal keepers and veterinarians. This study aimed to determine the occurrence of infection by B. coli in pigs of distinct husbandry categories, as well as unlike physiological state, kept in farms with different hygienic-sanitary standards, located in the central region of Rio Grande do Sul State in Brazil.Materials, Methods & Results: Stool samples were collected from 12 different farms with different hygienic-sanitary standards being four farms of finisher pigs (G1; n = 287), four farms with pregnant females (G2; n = 60) and four farms with lactation sows (G3;  n = 40), and all samples were submitted to coproparasitological analyses to verify the presence of cysts or trophozoites of B. coli. The infection levels were considered mild (1-100 cyst/trophozoite), moderate (101300 cyst/trophozoite) and high (>300 cysts/trophozoite). In addition, information about hygienic-sanitary conditions of each farm was collected. The occurrence of B. coli infection in all swine stool samples analyzed was 60.9% (236/387); however, in G1, G2 and G3 was 54.7% (157/287)

Balantidium coli in Pigs of Distinct Animal Husbandry Categories and Different Hygienic-Sanitary Standards in the Central Region of Rio Grande do Sul State, Brazil

Background: Balantidium coli is a commensal protozoan that infects several animals, but it has pigs as its natural reservoir. In the presence of predisposing factors, B. coli can become pathogenic for swine, causing enteric lesions. Infections determined by this protozoan may be a risk to public health, due to dysentery in animal keepers and veterinarians. This study aimed to determine the occurrence of infection by B. coli in pigs of distinct husbandry categories, as well as unlike physiological state, kept in farms with different hygienic-sanitary standards, located in the central region of Rio Grande do Sul State in Brazil.Materials, Methods & Results: Stool samples were collected from 12 different farms with different hygienic-sanitary standards being four farms of finisher pigs (G1; n = 287), four farms with pregnant females (G2; n = 60) and four farms with lactation sows (G3;  n = 40), and all samples were submitted to coproparasitological analyses to verify the presence of cysts or trophozoites of B. coli. The infection levels were considered mild (1-100 cyst/trophozoite), moderate (101300 cyst/trophozoite) and high (>300 cysts/trophozoite). In addition, information about hygienic-sanitary conditions of each farm was collected. The occurrence of B. coli infection in all swine stool samples analyzed was 60.9% (236/387); however, in G1, G2 and G3 was 54.7% (157/287)

Balantidium coli in Pigs of Distinct Animal Husbandry Categories and Different Hygienic-Sanitary Standards in the Central Region of Rio Grande do Sul State, Brazil

Background: Balantidium coli is a commensal protozoan that infects several animals, but it has pigs as its natural reservoir. In the presence of predisposing factors, B. coli can become pathogenic for swine, causing enteric lesions. Infections determined by this protozoan may be a risk to public health, due to dysentery in animal keepers and veterinarians. This study aimed to determine the occurrence of infection by B. coli in pigs of distinct husbandry categories, as well as unlike physiological state, kept in farms with different hygienic-sanitary standards, located in the central region of Rio Grande do Sul State in Brazil.Materials, Methods & Results: Stool samples were collected from 12 different farms with different hygienic-sanitary standards being four farms of finisher pigs (G1; n = 287), four farms with pregnant females (G2; n = 60) and four farms with lactation sows (G3;  n = 40), and all samples were submitted to coproparasitological analyses to verify the presence of cysts or trophozoites of B. coli. The infection levels were considered mild (1-100 cyst/trophozoite), moderate (101300 cyst/trophozoite) and high (>300 cysts/trophozoite). In addition, information about hygienic-sanitary conditions of each farm was collected. The occurrence of B. coli infection in all swine stool samples analyzed was 60.9% (236/387); however, in G1, G2 and G3 was 54.7% (157/287)

Balantidium coli in Pigs of Distinct Animal Husbandry Categories and Different Hygienic-Sanitary Standards in the Central Region of Rio Grande do Sul State, Brazil

Background: Balantidium coli is a commensal protozoan that infects several animals, but it has pigs as its natural reservoir. In the presence of predisposing factors, B. coli can become pathogenic for swine, causing enteric lesions. Infections determined by this protozoan may be a risk to public health, due to dysentery in animal keepers and veterinarians. This study aimed to determine the occurrence of infection by B. coli in pigs of distinct husbandry categories, as well as unlike physiological state, kept in farms with different hygienic-sanitary standards, located in the central region of Rio Grande do Sul State in Brazil.Materials, Methods & Results: Stool samples were collected from 12 different farms with different hygienic-sanitary standards being four farms of finisher pigs (G1; n = 287), four farms with pregnant females (G2; n = 60) and four farms with lactation sows (G3;  n = 40), and all samples were submitted to coproparasitological analyses to verify the presence of cysts or trophozoites of B. coli. The infection levels were considered mild (1-100 cyst/trophozoite), moderate (101300 cyst/trophozoite) and high (>300 cysts/trophozoite). In addition, information about hygienic-sanitary conditions of each farm was collected. The occurrence of B. coli infection in all swine stool samples analyzed was 60.9% (236/387); however, in G1, G2 and G3 was 54.7% (157/287)

Balantidium coli in Pigs of Distinct Animal Husbandry Categories and Different Hygienic-Sanitary Standards in the Central Region of Rio Grande do Sul State, Brazil

Background: Balantidium coli is a commensal protozoan that infects several animals, but it has pigs as its natural reservoir. In the presence of predisposing factors, B. coli can become pathogenic for swine, causing enteric lesions. Infections determined by this protozoan may be a risk to public health, due to dysentery in animal keepers and veterinarians. This study aimed to determine the occurrence of infection by B. coli in pigs of distinct husbandry categories, as well as unlike physiological state, kept in farms with different hygienic-sanitary standards, located in the central region of Rio Grande do Sul State in Brazil.Materials, Methods & Results: Stool samples were collected from 12 different farms with different hygienic-sanitary standards being four farms of finisher pigs (G1; n = 287), four farms with pregnant females (G2; n = 60) and four farms with lactation sows (G3;  n = 40), and all samples were submitted to coproparasitological analyses to verify the presence of cysts or trophozoites of B. coli. The infection levels were considered mild (1-100 cyst/trophozoite), moderate (101300 cyst/trophozoite) and high (>300 cysts/trophozoite). In addition, information about hygienic-sanitary conditions of each farm was collected. The occurrence of B. coli infection in all swine stool samples analyzed was 60.9% (236/387); however, in G1, G2 and G3 was 54.7% (157/287)

Balantidium coli in Pigs of Distinct Animal Husbandry Categories and Different Hygienic-Sanitary Standards in the Central Region of Rio Grande do Sul State, Brazil

Background: Balantidium coli is a commensal protozoan that infects several animals, but it has pigs as its natural reservoir. In the presence of predisposing factors, B. coli can become pathogenic for swine, causing enteric lesions. Infections determined by this protozoan may be a risk to public health, due to dysentery in animal keepers and veterinarians. This study aimed to determine the occurrence of infection by B. coli in pigs of distinct husbandry categories, as well as unlike physiological state, kept in farms with different hygienic-sanitary standards, located in the central region of Rio Grande do Sul State in Brazil.Materials, Methods & Results: Stool samples were collected from 12 different farms with different hygienic-sanitary standards being four farms of finisher pigs (G1; n = 287), four farms with pregnant females (G2; n = 60) and four farms with lactation sows (G3;  n = 40), and all samples were submitted to coproparasitological analyses to verify the presence of cysts or trophozoites of B. coli. The infection levels were considered mild (1-100 cyst/trophozoite), moderate (101300 cyst/trophozoite) and high (>300 cysts/trophozoite). In addition, information about hygienic-sanitary conditions of each farm was collected. The occurrence of B. coli infection in all swine stool samples analyzed was 60.9% (236/387); however, in G1, G2 and G3 was 54.7% (157/287)

Pesquisa de anticorpos anti-Neospora spp. e anti-herpersvírus equino em cavalos de tração no município de Santa Maria, RS, Brasil

This study aimed to investigate the prevalence of antibodies against Neospora spp and equine herpesvirus (EHV) among carter horses in Santa Maria, RS, Brazil. Serum samples from 91 horses, involved in the extension project "Programa de Ação Social Amigo do Carroceiro" at Universidade Federal de Santa Maria, were collected from March of 2006 to May of 2008. Immunofluorescence assay was used to detect Neospora spp. and virus neutralization assay to EHV. This research showed 15.4% (14/91) samples were positive to Neospora spp. and no antibodies against EHV were detected. These results suggest the presence of Neospora spp. in carter horses of Santa Maria. Additional studies are needed to determine the zoonotic potential risk and the sanitary importance this protozoan in the population analyzed.

O presente estudo teve como objetivo investigar a ocorrência de anticorpos contra Neospora spp. e o herpesvírus equino (EHV) em soros de cavalos de tração de Santa Maria, RS, Brasil. Os soros sanguineos provenientes de 91 animais do projeto de extensão da Universidade Federal de Santa Maria "Programa de Ação Social Amigos do Carroceiro" (PASAC) foram colhidos no período de março de 2006 a maio de 2008 e submetidos ao teste de imunofluorescência indireta para detecção de anticorpos anti-Neospora spp. e à técnica de soro neutralização para anticorpos anti-EHV. Constatou-se que 15,4% (14/91) das amostras foram reagentes para o Neospora spp. e não se verificou a presença da infecção pelo herpesvírus equino. Sugere-se a circulação do coccídeo na população equina estudada. Salienta-se a necessidade de estudos adicionais sobre o potencial risco zoonótico e a importância sanitária desse protozoário nos cavalos de tração.

Pesquisa de anticorpos anti-Neospora spp. e anti-herpersvírus equino em cavalos de tração no município de Santa Maria, RS, Brasil

This study aimed to investigate the prevalence of antibodies against Neospora spp and equine herpesvirus (EHV) among carter horses in Santa Maria, RS, Brazil. Serum samples from 91 horses, involved in the extension project "Programa de Ação Social Amigo do Carroceiro" at Universidade Federal de Santa Maria, were collected from March of 2006 to May of 2008. Immunofluorescence assay was used to detect Neospora spp. and virus neutralization assay to EHV. This research showed 15.4% (14/91) samples were positive to Neospora spp. and no antibodies against EHV were detected. These results suggest the presence of Neospora spp. in carter horses of Santa Maria. Additional studies are needed to determine the zoonotic potential risk and the sanitary importance this protozoan in the population analyzed.

O presente estudo teve como objetivo investigar a ocorrência de anticorpos contra Neospora spp. e o herpesvírus equino (EHV) em soros de cavalos de tração de Santa Maria, RS, Brasil. Os soros sanguineos provenientes de 91 animais do projeto de extensão da Universidade Federal de Santa Maria "Programa de Ação Social Amigos do Carroceiro" (PASAC) foram colhidos no período de março de 2006 a maio de 2008 e submetidos ao teste de imunofluorescência indireta para detecção de anticorpos anti-Neospora spp. e à técnica de soro neutralização para anticorpos anti-EHV. Constatou-se que 15,4% (14/91) das amostras foram reagentes para o Neospora spp. e não se verificou a presença da infecção pelo herpesvírus equino. Sugere-se a circulação do coccídeo na população equina estudada. Salienta-se a necessidade de estudos adicionais sobre o potencial risco zoonótico e a importância sanitária desse protozoário nos cavalos de tração.

Eficiência in vitro de acaricidas sobre carrapatos de bovinos no Estado do Rio Grande do Sul, Brasil

Infestation by ticks is responsible for significant economic losses to the cattle industry in several regions, including Rio Grande do Sul (RS) state. Losses may be derived from animal stress, weight loss and skin damage, as well as from costs with treatment. The indiscriminated use of pesticides against these parasites has resulted in high levels of genetic resistance to several drugs, representing a problem for disease control. Thus, the objective of this research was to evaluate the susceptibility of field specimens of Rhipcephalus (Boophilus) microplus to the acaricides used in the control of the parasite. Female ticks obtained from 42 farms in different counties of RS were submitted to the engorgeted female immersion test, to estimate the resistance of the parasite to the drugs. Amitraz in combination with chlorpyriphos was the most efficient drug, acting effectively in ticks from 100% of the tested farms (11/11). Associations of cypermethrin-chlorpyriphos-citronelol were efficient in ticks from 61% of the farms (25/41) and cypermethrin-ethion in 37% (10/27). Cypermethrin alone was efficient in 20,7% (6/29) and Amitraz. one of the most used products, was efficient in ticks from only 14,2% (6/42) of the farms. These results demonstrate that most drugs used in the control of R. B. microplus in the state present low efficacy, as measured by in vitro tests. The low drug efficacy is probably derived from the genetic resistance developed by the parasites due to the indiscriminated and inadequate use of these acaricides in the field.

A infestação por carrapatos em bovinos é responsável por perdas econômicas significativas à indústria animal em várias regiões brasileiras, incluindo o Rio Grande do Sul. As perdas se devem ao stress, a perdas de peso e a injúrias na pele, bem como aos custos com tratamentos. O uso indiscriminado de carrapaticidas tem contribuído para o aparecimento da resistência genética dos ixodídeos a várias drogas, representando um sério problema no controle de carrapatos. O objetivo deste trabalho foi avaliar a susceptibilidade das diferentes espécies de campo de Rhipicephalus (Boophilus) microplus aos acaricidas usados nos controles dos parasitas. Para tanto, amostras de carrapato foram coletadas em 42 propriedades localizadas em diferentes municípios do Estado para a realização do teste de imersão de teleóginas (biocarrapaticidograma). A associação do amitraz e do clorpirifós resultou na droga que apresentou maior eficácia em 100% das propriedades testadas (11/11). Associações com cipermethrina-clorpirifós-citronelol foram eficientes nos carrapatos em 61% das propriedades (25/41) e cipermetrina-ethion, em 37% (10/27). A cipermetrina foi eficiente em 20,7% (6/29) e o amitraz, um dos produtos mais utilizados nas propriedades, foi eficiente em 14,2% (6/42) das propriedades. Os resultados demonstraram que muitas drogas utilizadas no controle do R. (B.) microplus no Estado apresentaram baixa eficácia, conforme os resultados dos testes in vitro. A baixa eficácia das drogas provavelmente se deve à resistência genética desenvolvida pelos parasitas devido ao uso indiscriminado dos carrapaticidas a campo.

Suscetibilidade de linhagens celulares e cultivos primários ao Neospora caninum

Neospora caninum is a protozoan of wide distribution and great importance to the cattle industry, mainly due to its associated reproductive losses. Cultured cells are widely used for isolation and multiplication of the agent in vitro with several purposes. Thus, this study aimed to evaluate the susceptibility of different cell cultures to infection by N. caninum. Among the cell cultures tested, four presented good susceptibility to the agent: cell lines VERO (yield of 21.2 taquizoites/cell) and MA-104 (17.1); primary bovine testicle (16.3) and lung cells (13.6). Primary bovine kidney (8.2 taquizoites/cell), MDBK (5.1) and RK-13 cell lines (0.4) presented moderate to low sensitivity. No viable taquizoites were detected in the culture of MDCK cells. These results demonstrate that MA-104 cells present adequate susceptibility to N. caninum compared to VERO cells, which have been largely used to multiply the parasite in vitro. Together with its easy manipulation, fast multiplication and relatively low nutritional requirements, these results indicate that MA-104 cells are adequate for multiplication of N. caninum in vitro.

O Neospora caninum é um protozoário de ampla distribuição e grande importância na bovinocultura, principalmente pelas perdas reprodutivas que produz. Cultivos celulares são utilizados para o isolamento e a multiplicação do agente in vitro, com diversas finalidades. Este trabalho teve como objetivo avaliar a suscetibilidade de diferentes cultivos celulares à infecção pelo N. caninum. Dentre oito cultivos testados, quatro apresentaram boa susceptibilidade ao N. caninum: células VERO (produção de 21,2 taquizoítos/célula), MA-104 (17,1), cultivo primário de testículo (16,3) e pulmão bovino (13,6). Cultivo primário de rim bovino (8,2), células MDBK (5,1) e RK-13 (0,4) apresentaram baixa sensibilidade, enquanto células MDCK não produziram taquizoítos viáveis. Os resultados obtidos demonstram que as células MA-104 apresentaram suscetibilidade semelhante a das células VERO - linhagem tradicionalmente utilizada para o cultivo desse protozoário. Pela maior facilidade de cultivo, rápida multiplicação, menor exigência nutricional e produção de taquizoítos em níveis semelhantes às células VERO, as células MA-104 demonstraram ser adequadas para a manutenção e multiplicação do N. caninum in vitro.

Suscetibilidade de linhagens celulares e cultivos primários ao Neospora caninum

Neospora caninum is a protozoan of wide distribution and great importance to the cattle industry, mainly due to its associated reproductive losses. Cultured cells are widely used for isolation and multiplication of the agent in vitro with several purposes. Thus, this study aimed to evaluate the susceptibility of different cell cultures to infection by N. caninum. Among the cell cultures tested, four presented good susceptibility to the agent: cell lines VERO (yield of 21.2 taquizoites/cell) and MA-104 (17.1); primary bovine testicle (16.3) and lung cells (13.6). Primary bovine kidney (8.2 taquizoites/cell), MDBK (5.1) and RK-13 cell lines (0.4) presented moderate to low sensitivity. No viable taquizoites were detected in the culture of MDCK cells. These results demonstrate that MA-104 cells present adequate susceptibility to N. caninum compared to VERO cells, which have been largely used to multiply the parasite in vitro. Together with its easy manipulation, fast multiplication and relatively low nutritional requirements, these results indicate that MA-104 cells are adequate for multiplication of N. caninum in vitro.

O Neospora caninum é um protozoário de ampla distribuição e grande importância na bovinocultura, principalmente pelas perdas reprodutivas que produz. Cultivos celulares são utilizados para o isolamento e a multiplicação do agente in vitro, com diversas finalidades. Este trabalho teve como objetivo avaliar a suscetibilidade de diferentes cultivos celulares à infecção pelo N. caninum. Dentre oito cultivos testados, quatro apresentaram boa susceptibilidade ao N. caninum: células VERO (produção de 21,2 taquizoítos/célula), MA-104 (17,1), cultivo primário de testículo (16,3) e pulmão bovino (13,6). Cultivo primário de rim bovino (8,2), células MDBK (5,1) e RK-13 (0,4) apresentaram baixa sensibilidade, enquanto células MDCK não produziram taquizoítos viáveis. Os resultados obtidos demonstram que as células MA-104 apresentaram suscetibilidade semelhante a das células VERO - linhagem tradicionalmente utilizada para o cultivo desse protozoário. Pela maior facilidade de cultivo, rápida multiplicação, menor exigência nutricional e produção de taquizoítos em níveis semelhantes às células VERO, as células MA-104 demonstraram ser adequadas para a manutenção e multiplicação do N. caninum in vitro.

Eficiência in vitro de acaricidas sobre carrapatos de bovinos no Estado do Rio Grande do Sul, Brasil

Infestation by ticks is responsible for significant economic losses to the cattle industry in several regions, including Rio Grande do Sul (RS) state. Losses may be derived from animal stress, weight loss and skin damage, as well as from costs with treatment. The indiscriminated use of pesticides against these parasites has resulted in high levels of genetic resistance to several drugs, representing a problem for disease control. Thus, the objective of this research was to evaluate the susceptibility of field specimens of Rhipcephalus (Boophilus) microplus to the acaricides used in the control of the parasite. Female ticks obtained from 42 farms in different counties of RS were submitted to the engorgeted female immersion test, to estimate the resistance of the parasite to the drugs. Amitraz in combination with chlorpyriphos was the most efficient drug, acting effectively in ticks from 100% of the tested farms (11/11). Associations of cypermethrin-chlorpyriphos-citronelol were efficient in ticks from 61% of the farms (25/41) and cypermethrin-ethion in 37% (10/27). Cypermethrin alone was efficient in 20,7% (6/29) and Amitraz. one of the most used products, was efficient in ticks from only 14,2% (6/42) of the farms. These results demonstrate that most drugs used in the control of R. B. microplus in the state present low efficacy, as measured by in vitro tests. The low drug efficacy is probably derived from the genetic resistance developed by the parasites due to the indiscriminated and inadequate use of these acaricides in the field.

A infestação por carrapatos em bovinos é responsável por perdas econômicas significativas à indústria animal em várias regiões brasileiras, incluindo o Rio Grande do Sul. As perdas se devem ao stress, a perdas de peso e a injúrias na pele, bem como aos custos com tratamentos. O uso indiscriminado de carrapaticidas tem contribuído para o aparecimento da resistência genética dos ixodídeos a várias drogas, representando um sério problema no controle de carrapatos. O objetivo deste trabalho foi avaliar a susceptibilidade das diferentes espécies de campo de Rhipicephalus (Boophilus) microplus aos acaricidas usados nos controles dos parasitas. Para tanto, amostras de carrapato foram coletadas em 42 propriedades localizadas em diferentes municípios do Estado para a realização do teste de imersão de teleóginas (biocarrapaticidograma). A associação do amitraz e do clorpirifós resultou na droga que apresentou maior eficácia em 100% das propriedades testadas (11/11). Associações com cipermethrina-clorpirifós-citronelol foram eficientes nos carrapatos em 61% das propriedades (25/41) e cipermetrina-ethion, em 37% (10/27). A cipermetrina foi eficiente em 20,7% (6/29) e o amitraz, um dos produtos mais utilizados nas propriedades, foi eficiente em 14,2% (6/42) das propriedades. Os resultados demonstraram que muitas drogas utilizadas no controle do R. (B.) microplus no Estado apresentaram baixa eficácia, conforme os resultados dos testes in vitro. A baixa eficácia das drogas provavelmente se deve à resistência genética desenvolvida pelos parasitas devido ao uso indiscriminado dos carrapaticidas a campo.

Eficiência in vitro de acaricidas sobre carrapatos de bovinos no Estado do Rio Grande do Sul, Brasil

Infestation by ticks is responsible for significant economic losses to the cattle industry in several regions, including Rio Grande do Sul (RS) state. Losses may be derived from animal stress, weight loss and skin damage, as well as from costs with treatment. The indiscriminated use of pesticides against these parasites has resulted in high levels of genetic resistance to several drugs, representing a problem for disease control. Thus, the objective of this research was to evaluate the susceptibility of field specimens of Rhipcephalus (Boophilus) microplus to the acaricides used in the control of the parasite. Female ticks obtained from 42 farms in different counties of RS were submitted to the engorgeted female immersion test, to estimate the resistance of the parasite to the drugs. Amitraz in combination with chlorpyriphos was the most efficient drug, acting effectively in ticks from 100% of the tested farms (11/11). Associations of cypermethrin-chlorpyriphos-citronelol were efficient in ticks from 61% of the farms (25/41) and cypermethrin-ethion in 37% (10/27). Cypermethrin alone was efficient in 20,7% (6/29) and Amitraz. one of the most used products, was efficient in ticks from only 14,2% (6/42) of the farms. These results demonstrate that most drugs used in the control of R. B. microplus in the state present low efficacy, as measured by in vitro tests. The low drug efficacy is probably derived from the genetic resistance developed by the parasites due to the indiscriminated and inadequate use of these acaricides in the field.

A infestação por carrapatos em bovinos é responsável por perdas econômicas significativas à indústria animal em várias regiões brasileiras, incluindo o Rio Grande do Sul. As perdas se devem ao stress, a perdas de peso e a injúrias na pele, bem como aos custos com tratamentos. O uso indiscriminado de carrapaticidas tem contribuído para o aparecimento da resistência genética dos ixodídeos a várias drogas, representando um sério problema no controle de carrapatos. O objetivo deste trabalho foi avaliar a susceptibilidade das diferentes espécies de campo de Rhipicephalus (Boophilus) microplus aos acaricidas usados nos controles dos parasitas. Para tanto, amostras de carrapato foram coletadas em 42 propriedades localizadas em diferentes municípios do Estado para a realização do teste de imersão de teleóginas (biocarrapaticidograma). A associação do amitraz e do clorpirifós resultou na droga que apresentou maior eficácia em 100% das propriedades testadas (11/11). Associações com cipermethrina-clorpirifós-citronelol foram eficientes nos carrapatos em 61% das propriedades (25/41) e cipermetrina-ethion, em 37% (10/27). A cipermetrina foi eficiente em 20,7% (6/29) e o amitraz, um dos produtos mais utilizados nas propriedades, foi eficiente em 14,2% (6/42) das propriedades. Os resultados demonstraram que muitas drogas utilizadas no controle do R. (B.) microplus no Estado apresentaram baixa eficácia, conforme os resultados dos testes in vitro. A baixa eficácia das drogas provavelmente se deve à resistência genética desenvolvida pelos parasitas devido ao uso indiscriminado dos carrapaticidas a campo.

Suscetibilidade de linhagens celulares e cultivos primários ao Neospora caninum

Neospora caninum is a protozoan of wide distribution and great importance to the cattle industry, mainly due to its associated reproductive losses. Cultured cells are widely used for isolation and multiplication of the agent in vitro with several purposes. Thus, this study aimed to evaluate the susceptibility of different cell cultures to infection by N. caninum. Among the cell cultures tested, four presented good susceptibility to the agent: cell lines VERO (yield of 21.2 taquizoites/cell) and MA-104 (17.1); primary bovine testicle (16.3) and lung cells (13.6). Primary bovine kidney (8.2 taquizoites/cell), MDBK (5.1) and RK-13 cell lines (0.4) presented moderate to low sensitivity. No viable taquizoites were detected in the culture of MDCK cells. These results demonstrate that MA-104 cells present adequate susceptibility to N. caninum compared to VERO cells, which have been largely used to multiply the parasite in vitro. Together with its easy manipulation, fast multiplication and relatively low nutritional requirements, these results indicate that MA-104 cells are adequate for multiplication of N. caninum in vitro.

O Neospora caninum é um protozoário de ampla distribuição e grande importância na bovinocultura, principalmente pelas perdas reprodutivas que produz. Cultivos celulares são utilizados para o isolamento e a multiplicação do agente in vitro, com diversas finalidades. Este trabalho teve como objetivo avaliar a suscetibilidade de diferentes cultivos celulares à infecção pelo N. caninum. Dentre oito cultivos testados, quatro apresentaram boa susceptibilidade ao N. caninum: células VERO (produção de 21,2 taquizoítos/célula), MA-104 (17,1), cultivo primário de testículo (16,3) e pulmão bovino (13,6). Cultivo primário de rim bovino (8,2), células MDBK (5,1) e RK-13 (0,4) apresentaram baixa sensibilidade, enquanto células MDCK não produziram taquizoítos viáveis. Os resultados obtidos demonstram que as células MA-104 apresentaram suscetibilidade semelhante a das células VERO - linhagem tradicionalmente utilizada para o cultivo desse protozoário. Pela maior facilidade de cultivo, rápida multiplicação, menor exigência nutricional e produção de taquizoítos em níveis semelhantes às células VERO, as células MA-104 demonstraram ser adequadas para a manutenção e multiplicação do N. caninum in vitro.