Effects of infection with Toxoplasma gondii oocysts on the intestinal wall and the myenteric plexus of chicken (Gallus gallus)

This paper aims to analyze the effects of the Toxoplasma gondii infection in the intestinal wall and myenteric plexus of chicken (Gallus gallus). Ten 36-day-old chickens were separated into two groups: control and experimental, orally inoculated with oocysts of the T. gondii strain M7741 genotype III. After 60 days the birds were submitted to euthanasia and had their duodenum removed. Part of the intestinal segments was submitted to histological routine, HE staining, PAS histochemical technique, and Alcian Blue. Qualitative analysis of the intestinal wall and comparative measurements among the groups with respect to total wall thickness, muscle tunic, mucosa, and tunica mucosa were carried out. Caliciform cells were quantified. The other part of the intestinal segments was fixed in formol acetic acid and dissected having the tunica mucosa and the tela submucosa removed. Neurons were stained with Giemsa, counted, and measured. Chickens from the experimental group presented diarrhea and inflammatory infiltrates in the tunica mucosa, thickness reduction of all the parameters assessed in the intestinal wall, and an increase of the number of caliciform cells. There was a ~70% reduction regarding the intensity of myenteric neurons; and the remaining cells presented a reduction of ~2.4% of the perikarion and ~40.5% of the nucleus (p<0.05). Chronic infection induced by T. gondii oocysts resulted in intestinal wall atrophy, mucin secretion increase, death and atrophy of chicken myenteric plexus neurons. Death and atrophy of myenteric plexus neurons may be related with the causes of diarrhea observed in chickens with toxoplasmosis.

Detecção de Toxoplasma gondii no sêmen de ovinos naturalmente infectados

O objetivo deste trabalho foi estudar a eliminação de Toxoplasma gondii no sêmen de carneiros naturalmente infectados. Foram utilizados 65 reprodutores submetidos inicialmente à pesquisa de anticorpos anti-T. gondii por meio da técnica de imunofluorescência indireta (IFI). Os carneiros sorologicamente positivos foram submetidos à colheita de sêmen para detecção do DNA de T. gondii. Na sorologia observaram-se 6/65 (9,2%) carneiros positivos, enquanto no PCR nested de sêmen 4/6 (66,6%) carneiros foram positivos. Conclui-se que a detecção, por meio da técnica da PCR nested, da forma proliferativa de T. gondii no sêmen de carneiros naturalmente infectados, reforça a necessidade de se pesquisar sobre a possibilidade da transmissão horizontal do parasito via sêmen na espécie ovina.

Fatores associados a soroprevalência de Neospora caninum e Toxoplasma gondii em rebanhos caprinos na região sul de Minas Gerais

Este estudo estabelece a soroprevalência de Neospora caninum e Toxoplasma gondii em rebanhos caprinos no Sul de Minas Gerais e verifica a sua associação com o desempenho reprodutivo dos rebanhos analisados, uma vez que não há dados sobre neosporose em caprinos neste Estado. Amostras de soro de 401 caprinos provenientes de 11 propriedades foram submetidas à reação de imunofluorescência indireta anti-N. caninum e T. gondii. A prevalência média de animais positivos foi de 10,7% e 21,4%, respectivamente. Houve diferença significativa entre as faixas etárias. Neste quesito os maiores índices de positividade, para ambos os parasitas, foram observados nos caprinos acima de três anos de idade. Estes apresentaram uma probabilidade 2,6 e 4,8 maior, em relação aos animais de até um ano de idade, para N. caninum e T. gondii, respectivamente. No teste T não houve associação positiva entre as médias de prevalência de N. caninum (p=0,553) e T. gondii (p=0,098) com a ocorrência de problema reprodutivo nos rebanhos. Porém, propriedades com histórico de problemas reprodutivos apresentaram uma média de reagentes para N. caninum de 18,64%, se comparadas a 13,97% de criatórios que não relataram essas alterações. Quando os problemas reprodutivos foram separados em categorias a relação entre a ocorrência de aborto e a soroprevalência de N. caninum e de T. gondii foi significativa (p<0,05) por meio dos testes Exato de Fisher e Qui-quadrado. Não houve diferença (p>0,05) entre as médias de prevalência de T. gondii e o acesso de gatos ao rebanho no teste T. Entretanto, a média de prevalência nas propriedades em que os gatos tinham acesso foi de 31,01%, se comparada a 17,34% em criatórios onde não existiam gatos. Foi constatado o acesso de cães em 100% das propriedades. Os resultados obtidos neste estudo demonstram que N. caninum e T. gondii infectam caprinos no Sul de Minas Gerais e que estes parasitas podem estar associados à ocorrência de abortos nessa espécie animal.

Prevalência e fatores de risco associados à infecção por Toxoplasma gondii em granjas suinícolas tecnificadas no Estado de Alagoas

Objetivou-se com este estudo calcular a prevalência e identificar os fatores de risco associados à infecção por Toxoplasma gondii em suínos criados em granjas tecnificadas no Estado de Alagoas, Brasil. Para compor a amostra do estudo de prevalência foram utilizados 342 suínos, sendo 312 matrizes e 30 varrões, oriundos de sete granjas de ciclo completo e distribuídas em cinco municípios do Estado de Alagoas. O exame sorológico para a pesquisa de anticorpos anti-Toxoplasma gondii foi realizado através da técnica de Imunofluorescência Indireta (RIFI), utilizando-se anticorpos anti-IgG-suíno conjugado ao isotiocianato de fluoresceína. A análise dos fatores de risco foi realizada por meio da aplicação de questionários constituídos por perguntas objetivas referentes ao criador, às características gerais da propriedade, ao manejo produtivo, reprodutivo e sanitário. Determinou-se uma prevalência de 26,9% (92/342) de suínos soropositivos. O fator associado à infecção foi a introdução de reprodutores nas granjas nos últimos cinco anos (p=0,014; OR=1,83; IC=1,13-2,96). Concluiu-se que a infecção por Toxoplasma gondii encontra-se disseminada em suínos criados em granjas tecnificadas no Estado de Alagoas, Brasil. Recomenda-se o controle da população de gatos, a realização de práticas de limpeza e higienização das instalações e realização de testes laboratoriais para diagnóstico da infecção por T. gondii nos animais a serem introduzidos no plantel como medidas de redução dos índices de infecção na região estudada.

Sparrows (Passer domesticus L.) as intermediary hosts of Toxoplasma gondii in poultry farms from the "agreste" region of Pernambuco, Brazil

This paper aimed to identify Toxoplasma gondii infection in house sparrows (Passer domesticus, Linneaus 1758) coming from poultry farms in the "agreste" region of the Brazilian state of Pernambuco. 151 sparrows (Passer domesticus) captured in eight broiler, egg layer and commercial laying poultry farms, were used. Indirect hemagglutination test was used to research anti-T. gondii antibodies. Animals that presented titration of 1:16 were destined to DNA research through Polymerase Chain Reaction (PCR) technique, followed by Nested-PCR. It was observed that, from 151 analyzed samples. 91 (60.3%) were reagents and 60 (39.7%) were not reagents. It was verified, through analysis of the distribution of infected animals frequency per farm, that in only one farm (12.5%) no animal reagent to T. gondii was captured. It was also observed that three (30.00%) of the ten samples destined to DNA research for T. gondii were positive to PCR and four (40.00%) were positive to Nested-PCR. Anti-T gondii antibodies occurrence and the molecular identification of the agent confirmed natural T. gondii infection in sparrows from poultry farms in Brazil. Other studies must be carried out to highlight the real importance of these animals in the epidemiological chain and their efficiency in the transmission of the parasite to felines. Therefore, researches that use parasite isolation and molecular techniques to determine genomic profile of the agent present in these poultry farms are needed.

Risk factors associated with Toxoplasma gondii infection in dairy cattle, state of Rio de Janeiro

Toxoplasmosis is one of the most common parasitic zoonoses throughout the world. Infection in man and animals varies in different geographical areas influenced by many environmental conditions. Seroprevalence of Toxoplasma gondii infection in cattle in Brazil ranges from 1.03 to 71%. A cross-sectional survey was carried out in 58 out of 453 farms in the South Fluminense Paraiba Valley, State of Rio de Janeiro, Brazil. Over 3-year-old cattle (n=589) from dairy herds were selected for blood collection and detection of anti-T. gondii antibodies by indirect immunofluorescence reaction (IFA) with initial titration of 1:16; titers > 64 were considered positive. Univariate analysis of risk factors showed that cats in contact with cattle, cats in contact with drinking water, and number of cats were associated with T. gondii seroprevalence. Logistic regression revealed a two-fold increased risk for infection of cattle (p=0.0138) through larger number of cats (>3) compared with low numbers of cats (1-2) on the farm. In contrast, the presence of chickens was considered a protective factor (p=0.025).

Occurrence of anti-Neospora caninum and anti-Toxoplasma gondii antibodies in dogs with visceral leishmaniasis

Uninfected dogs and those naturally infected with Leishmania chagasi exhibiting different clinical forms of disease were evaluated for the presence of anti-Neospora caninum and anti-Toxoplasma gondii antibodies. Blood samples were collected from 110 mongrel dogs. Sera were tested using the indirect fluorescent antibody test (IFAT), and the animals with visceral leishmaniasis (VL) (n=60) were classified clinically. Out of the 110 sera investigated, 5 (4.5%) were positive for N. caninum (IFAT>50) and 36 (32.7%) for T. gondii (IFAT>16). Anti-L. chagasi antibody titers in asymptomatic dogs (n=10) were found to be significantly lower (P<0.05) than those in oligosymptomatic ones (n=22), which were in turn significantly lower (P<0.05) than those in symptomatic ones (n=28). No association between Leishmania and N. caninum infections was observed. Among dogs infected with L. chagasi, a tendency (P=0.053) towards an association between the infection with T. gondii and the appearance of VL symptoms was observed, suggesting that the clinical manifestation of VL in dogs may enhance their susceptibility to T. gondii. The possible influence of the immunosuppressive status of canine leishmaniasis in the different clinical forms of the disease is discussed.

Outbreak of caprine abortion by Toxoplasma gondii in Midwest Brazil

An outbreak of abortion by Toxoplasma gondii in goats on a farm in the Brazilian Midwest is reported. Gross lesions were not observed in seven aborted fetuses submitted to the Veterinary Pathology Laboratory, Federal University of Mato Grosso, for necropsy investigation. The main histologic lesions were mononuclear cell pneumonia and necrotizing encephalitis in varying degrees of intensity. PCR for Brucella abortus and Neospora caninum and aerobic cultures were negative in all cases. Antibody titles against T. gondii varying from 1:1024 to 1:32.768 were detected in serum samples from four aborted goats. Nested-PCR assay for T. gondii were positive in brain samples of all cases submitted. These findings indicate that T. gondii infection should be considered in the diagnosis of abortion in goats in Midwest Brazil.

Fatores de risco associados à infecção por Toxoplasma gondii em ovinos e caprinos no estado de Pernambuco

Objetivou-se com este estudo investigar a participação de Toxoplasma gondii em falhas reprodutivas em pequenos ruminantes de criatórios situados na Zona da Mata e no Agreste do Estado de Pernambuco e que apresentavam histórico de distúrbios reprodutivos. Foram selecionadas 12 propriedades das quais se coletaram amostras de 262 animais, sendo 167 caprinos e 95 ovinos. Realizou-se a pesquisa de anticorpos anti-Toxoplasma gondii, utilizando-se a técnica da Imunofluorescência Indireta (RIFI). Foram aplicados questionários investigativos nas propriedades visitadas para identificar os fatores de risco associados à infecção. Em 100% das propriedades foram encontrados animais soropositivos. Para T. gondii, das 167 amostras de soro caprino analisadas, 31,7% foram positivas, enquanto que na espécie ovina, das 95 amostras, 16,9% foram positivas. Para a espécie ovina, não foram observadas associações significativas. Para os caprinos, houve associação significativa (p<0,05) para as variáveis: manejo intensivo (OR=2,40), exploração leiteira (OR=2,10), animais procedentes de outros estados (OR=7,89) e monta natural (OR=5,69). Conclui-se que a infecção pelo T. gondii encontra-se disseminada nos rebanhos de caprinos e ovinos estudados e que medidas sanitárias devem ser adotadas para controlar os fatores de risco identificados neste estudo.

Occurrence of infection with Toxoplasma gondii and factors associated with transmission in broiler chickens and laying hens in different raising systems

Toxoplasmosis is a zoonotic disease caused by the protozoan Toxoplasma gondii. The aim of the present study was to determine the occurrence and identify the risk factors associated with transmission of T. gondii to chickens raised in different systems (free-ranged and confined) to produce eggs or meat. The 810 animals were allocated in two experimental groups according to the production system purpose: 460 broiler chickens (Group 1) and 350 layer chickens (Group 2). In order to analyze the possible factors involved in T. gondii infection in the chickens, an epidemiological questionnaire was developed for all properties.The serological detection of anti-Toxoplasma gondii antibodies was performed by Indirect Immunofluorescence (IFAT) and by Enzime Linked Imunossorbent Assay (ELISA). Since the agreement index (kappa) between these two serological techniques was considered high, 21.2% of the 810 animals were considered reactive. In Group 1, 12.2% (56/460) were positive, while in the Group 2 the positivity rate was 33.1% (116/350). The production system may be influencing the seropositivity of the animals in both groups. However, only in Group 2 it was possible to notice a statistically significant relationship between the breeding system and the frequency of positive sera. This result indicates that, at least for laying hens, the production system is directly involved in T. gondii infection. The contact with cats in Group 1 did not influence the distribution of seroreactive animals, but in Group 2 a significant relationship was observed. The occurrence of anti-T. gondii antibodies was high in both groups (broiler and posture chickens). Free-ranged chickens raised for egg production proved to be the most exposed group to the T. gondii infection. This can be related to the fact that these animals stay for longer periods in the farms, in direct contact with possibly contaminated soil by the presence of domestic cats.

Serologic and molecular diagnostic and bioassay in mice for detection of Toxoplasma gondii in free ranges chickens from Pantanal of Mato Grosso do Sul

The aim of this study was to investigate the occurrence of Toxoplasma gondii and compare the results obtained in the Modified Agglutination Test (MAT), Polimerase Chain Reaction (PCR) and bioassay in mice. In order to accomplish this, 40 free-range chickens from eight farms in neighboring areas to the Pantanal in Nhecolândia, Mato Grosso do Sul, were euthanized and blood samples, brain and heart were collected. The occurrence of anti-T. gondii antibodies found in chickens was 67.5% (27 samples), considering as a cutoff point the dilution 1:5. Among the samples analyzed, 7 (25.9%) were positive in the dilution 1:5, 3 (11.1%) in 1:10, 2 (7.4%) in 1:20, 3 (11.1%) in 1:320, 1 ( 3.7%) in 1:640, 3 (11.1%) in 1:1280, 2 (7.4%) in 1:2560, 4 (14.8%) in 1:5120 and 2 (7.4%) in 1:10.240. From the mixture of tissue samples (brain and heart) from the chickens analyzed, 16 (40%) presented electrophoretic bands compatible with T. gondii by PCR (gene B1). In the comparison of techniques, 59.26% positivity in PCR was revealed among animals that were seropositive in MAT (cutoff 1:5). From 141 inoculated mice, six (4.44%) died of acute toxoplasmosis between 15 and 23 days after inoculation. Surviving mice were sacrificed at 74 days after inoculation, and a total of 28 cysts were found in the brains of 10 distinct groups. From the seropositive hens, 27 bioassays were performed and 11 (40.7%) isolates were obtained. A greater number of isolations happened in mice that were inoculated with tissues from chickens that had high titers for anti-T. gondii antibodies. Chronic infection in mice was observed in nine groups (33.3%) from five different properties. Among the surviving mice, 25.6% were positive for T. gondii in MAT (1:25). From mice positive in PCR, 87.5% were also positive in MAT. Among the PCR-negative mice, 5.2% were positive for T. gondii in MAT. It can be concluded through this study that the occurrence of infecton by T. gondii in the rural properties studied was high, that PCR directed to gene B1 does not confirm the viability of the parasite, but it can be used as a screening method for the selection of chickens infected by T. gondii, that the animals with titer greater than 10 must be prioritized for the selection of animals for bioassay, since for them, the chances of isolating the parasite are greater and that seroconversion in experimentally infected mice is not a good indicator for isolating the agent.

Situação epidemiológica da infecção por Toxoplasma gondii em equídeos na microrregião do Brejo Paraibano

Objetivou-se com o estudo caracterizar a situação epidemiológica da infecção por Toxoplasma gondii em equídeos na microrregião do Brejo Paraibano, região Nordeste do Brasil. Anticorpos contra T. gondii foram pesquisados em 257 amostras de equídeos (204 equinos, 46 muares e sete asininos) em 26 propriedades. Para o diagnóstico sorológico utilizou-se a Reação de Imunofluorescência Indireta (RIFI) e um ponto de corte de 1:64. O número de focos encontrado foi de 46,1%. Nas amostras analisadas, a prevalência geral foi de 7,8% (I.C. 4,8-8,8). A prevalência foi de 8,3% (I.C. 4,9-13,0) para os equinos, 2,2% (I.C. 0,1-11,5) para os muares e 28,6% (I.C. 3,7-71,0) entre os asininos. Na regressão logística das variáveis observou-se que a fonte de água foi um fator de risco, pois naquelas propriedades que forneciam água corrente para os animais o risco de infecção foi 4,4 vezes maior do que naquelas propriedades que forneciam água parada (OR 4,4; I.C. 1,0-19,0). Este é o primeiro relato da presença de anticorpos contra T. gondii em equídeos nessa microrregião do estado da Paraíba. Para diminuir os riscos de infecção nestas espécies, deve-se fornecer aos animais uma água de boa qualidade, bem como evitar acesso de gatos a fontes de água e instalações onde os animais são mantidos.

Infection by Toxoplasma gondii in Neotropical non-human primates

Toxoplasma gondii (Nicolle et Manceaux, 1909) is an obligatory intracellular protozoan parasite of warm animals, including human and non-human primates. Domestic and wild felids are considered definitive hosts. Several authors have already identified lesions in New World primates caused by T. gondii. Nevertheless, little is known about serological studies on those animals. With this reason, New World non-human primates of the genera Cebus and Callithrix that were apprehended by governmental authorities and sent to the Wildlife Screening Center (Cetas)/IBAMA, at the municipality of Seropédica, state of Rio Janeiro, were bled and sera were submitted to the indirect hemagglutination test for detection of anti-T. gondii antibodies. From 21 sera of Cebus primates, 76.19% (16/21) had anti-T. gondii antibodies. Titles varied from 16 to 2048. In samples from 21 Callithrix, only 4.5% (1/22) had anti-T. gondii antibodies. Only one animal had a title of 32. During all the time those animals were clinical evaluated until sample was collected; none of them had any clinical sign or sequel related to infection by T. gondii. The fact that the origin of these primates is unknown and that there is no information about their feeding habits before captivity makes it difficult to determine the source of T. gondii infection.

Frequency of Toxoplasma gondii antibodies in tufted capuchin monkeys (Cebus apella nigritus) from an ecological station in the State of São Paulo, Brazil

Toxoplasmosis is a worldwide zoonosis caused by Toxoplasma gondii, an obligate intracellular parasite protozoan. A large percentage of animals presents specific antibodies caused by a previous exposition, resulting in a chronic infection. Felides are the definitive hosts and the other warm-blooded animals, including primates, are the intermediate hosts. This study was aimed to determine the prevalence of T. gondii infection in free-living tufted capuchin monkeys (Cebus apella nigritus) from an ecological station located on Mata de Santa Teresa, Ribeirão Preto, SP, Brazil. T. gondii antibodies were analyzed by modified agglutination test (MAT) in serum samples of 36 tufted capuchin monkeys, considering eight as cut-off titer. From the studied animals, 3/36 (8.33%; CI95% 3.0-21.9%) presented T. gondii antibodies, all with titer 32. No significative difference was observed relating to the sex (1/3 male and 2/3 female), and to the age (1/3 young and 2/3 adult) (P>0.05). Thus, these results demonstrate the presence of T. gondii antibodies in primates from São Paulo state.

Soroprevalência e fatores associados à infecção por Toxoplasma gondii em caprinos de propriedades rurais do município de Mossoró, RN

O município de Mossoró/RN, no Nordeste do Brasil, tem como destaque a criação de caprinos. A toxoplasmose é uma zoonose que é mais patogênico para os caprinos do que para os demais animais de abate. Em caprinos, o protozoário frequentemente é responsável por problemas reprodutivos e perdas econômicas. Com o objetivo de identificar a soroprevalência e os fatores de risco da toxoplasmose em caprinos de propriedades rurais do Município de Mossoró, amostras de soro de 338 animais (320 fêmeas e 18 machos) de 15 unidades produtoras foram testados pelo Ensaio Imunoenzimático (ELISA). Das 15 propriedades, 14 apresentaram animais soropositivos para toxoplasmose, e nestas o total de animais positivos foram de 125 (123 fêmeas e 2 machos), obtendo uma prevalência de 37,0%. Houve uma relação significativa (p<0,05) entre a prevalência e o sexo, e entre a prevalência e raça dos animais. As chances de ocorrer (OR) mais importantes associados à infecção por Toxoplasma gondii foram: fonte de água (OR=2,635), vasilhames para a água dos animais localizado fora das instalações da propriedade (OR=3,121) e a exploração do tipo leiteira (OR=2,546). Pela análise do ELISA de avidez, foram encontradas fêmeas em idade reprodutiva na fase aguda da infecção.