José Leonardo Nicolau

Seroprevalence and risk factors of toxoplasmosis in cattle from extensive and semi-intensive rearing systems at Zona da Mata, Minas Gerais state, Southern Brazil.

BackgroundConcerning the infection of humans by T. gondii, limited efforts have been directed to the elucidation of the role of horizontal transmission between hosts. One of the main routes of transmission from animals to humans occurs through the ingestion of raw or insufficiently cooked meat. However, even though the detection of T. gondii in meat constitutes an important short-term measure, control strategies can only be accomplished by a deeper understanding of the epidemiology of toxoplasmosis. The present study aimed to investigate the seroprevalence of toxoplasmosis in cattle from Zona da Mata, Minas Gerais, Brazil, and to identify associated risk factors, through an epidemiological investigation.MethodsThe animals studied (Bos indicus, breed Nelore or Gir) were reared in the Zona da Mata micro-region and killed at a commercial slaughterhouse at Juiz de Fora, Minas Gerais state. The animals came from 53 cattle farms with extensive (predominantly pasture feeding management) or semi-intensive (food management based on grazing, salt mineral and feed supplementation) rearing systems. Blood samples were collected from 1200 animals, and assigned to Indirect Fluorescent Antibody Test.ResultsWhen analyzing IgG anti-T.gondii we found an overall seroprevalence of 2.68%. In Brazil prevalences vary from 1.03% to 60%. Although in the present study, the seroprevalence per animal is considered low compared to those observed in other studies, we found out that of the 53 farms analyzed, 17 (34.69%) had one or more positive cattle. It is a considerable percentage, suggesting that the infection is well distributed through the Zona da Mata region. The results of the epidemiological investigation showed that the main risk factors of Toxoplasma gondii infection are related to animal management and to the definive host. There was a relationship between the number of seropositive cattle and the presence and number of resident cats, presence and number of stray cats, presence of cats walking freely, rat control by using cats and feed storage.ConclusionThese results may contribute to the development of preventive strategies in Brazil and other developing countries were extensive and semi-intensive cattle rearing systems are very widespread and the efforts to control this important zoonotic disease have attained little success.

Sensitivity and specificity of serological tests, histopathology and immunohistochemistry for detection of Toxoplasma gondii infection in domestic chickens

Since free-range chickens are important for the epidemiology of toxoplasmosis, this study evaluated the sensitivity and specificity of different laboratory techniques for the diagnosis of Toxoplasma gondii in these animals. Serum samples from 135 adult domestic chickens were tested for anti-T. gondii antibodies by the indirect fluorescent antibody test (IFAT), enzyme-linked immunosorbent assay (ELISA), modified agglutination test (MAT), and indirect hemagglutination test (IHAT). Tissue samples from all animals were analyzed by histopathology, immunohistochemistry and mouse bioassay (gold standard). Fifty-four chickens were positive for T. gondii in the bioassay. The sensitivity and specificity of the different tests were, respectively, 85% and 56% for ELISA; 80% and 52% for IFAT; 76% and 68% for MAT; 61% and 80% for IHAT; 7% and 98% for immunohistochemistry, and 6% and 98% for histopathology. The MAT was the most effective method for the diagnosis of T. gondii infection in chickens, followed by ELISA. Histopathology and immunohistochemistry are useful tools for the diagnosis of T. gondii infection in chickens due to their specificity.

Prevalence and risk factors for Toxoplasma gondii infection among pregnant and postpartum women attended at public healthcare facilities in the City of Niterói, State of Rio de Janeiro, Brazil.

INTRODUCTION To determine the prevalence of immunoglobulin G (IgG) and immunoglobulin M (IgM) anti-Toxoplasma gondii antibodies among pregnant and postpartum women attended within the public healthcare system in Niterói, State of Rio de Janeiro,and to detect possible exposure factors associated with T. gondii infection in this population. METHODS IgM and IgG anti- T. gondii antibodies were investigated in 276 pregnant and 124 postpartum women by using the indirect immunofluorescence (IFAT) and immunoenzymatic assay (ELISA) techniques. The participants were selected by convenience sampling. All these 400 patients filled out a free and informed consent statement, answered an epidemiological questionnaire and were informed about the disease. RESULTS Among the 400 samples analyzed, 234 (58.5%) were reactive to IgG anti-T. gondii antibodies, according to the IFAT and/or ELISA assay. One pregnant woman was found to be reactive to IgM anti- T. gondii antibodies, with an intermediate IgG avidity test. Risk factor analysis showed that seropositivity was significantly associated (p<0.05) with age, contact with cats and presence of rodents at home. Through a logistic regression model, these associations were confirmed for age and contact with cats, while education at least of the high school level was found to be a protective factor. CONCLUSIONS The prevalence rate of IgG anti-T. gondii antibodies in the city of Niterói was high and the risk factors for infection detected after multivariate analysis were: age over 30 years, contact with cats and education levels lower than university graduate level.

Seroprevalence of Toxoplasma gondii infection in swine matrices in Nova Mutum and Diamantino, Mato Grosso, Brazil

This report aimed to assess the seroprevalence of Toxoplasma gondii infection in 708 swine matrices in Nova Mutum and Diamantino in the state of Mato Grosso, Central-West Brazil. Serum samples were examined by indirect fluorescent antibody test (IFAT). It was found a seroprevalence of 12.8%, considering titers ≥ 64. Therefore, the data reinforce the need for appropriate management of swine raising to minimize the risk of infection of pigs with T. gondii.

Occurrence of anti-Toxoplasma gondii antibodies in cattle and pigs slaughtered, State of Rio de Janeiro.

This study aimed to estimate the occurrence of anti-Toxoplasma gondii antibodies by means of the Indirect Immunufluorescent Antibody Assay (IFAT) in cattle and pigs from slaughterhouses in two municipalities in the State of Rio de Janeiro. IgG anti-T. gondii antibodies was found in 1.96% (9/459) of the cattle and 7.64% (31/406) of the pigs, without any positive association (p > 0.05) with risk factors for transmission and seropositivity. Taking the cutoff point of IFAT ³ 1:64, titers of 64 and 256 were detected, suggesting chronic infection. Despite the low prevalence rates found for cattle and pigs, these indicated environmental contamination in the municipalities investigated, biosafety failures at the technified pig farm evaluated and the possibility of human and animal infection through eating raw or undercooked meat from these animals.

Soroepidemiologia da toxoplasmose em caprinos e ovinos de três municípios do Estado do Rio de Janeiro

Toxoplasmosis is a worldwide zoonosis caused by Toxoplasma gondii. Epidemiological surveys of T. gondii infection among livestock have great economical importance since this infection may cause abortion, growth retardation and neonatal mortality, with significant losses to breeders. In regard of public health, human infection can be acquired by ingestion of meat or milk in natura from infected livestock. The aim of this study was to assess the toxoplasmosis seroprevalence by indirect immunofluorescence antibody test (IFAT) in goats and sheep, in three counties of Rio de Janeiro state, from 10 different farms. The seroprevalences of anti-T.gondii IgG antibodies were 29.12% (60/206) in goats and 38.05% (137/360) in sheep, with titers ranging from 64 to 256, suggesting chronic infection. Association of each of the following epidemiological factors: female gender, adult age, extensive management system, grazing pasture and drinking lake water with seropositivity was observed only in sheep (p<0.05). Improvement in breeding conditions may reduce the sources of infection in herds.

Mapping of the environmental contamination of Toxoplasma gondii by georeferencing isolates from chickens in an endemic area in Southeast Rio de Janeiro State, Brazil

The environmental contamination of Toxoplasma gondii in an endemic area in Brazil was mapped by georeferencing isolates from chickens in farms in the Southeast of the state of Rio de Janeiro. Tissue samples obtained from 153 adult chickens were analyzed by the mouse bioassay for T. gondii infection. These animals were reared free-range on 51 farms in the municipalities of Rio Bonito and Maricá. The ArcGIS kernel density estimator based on the frequency of T. gondii-positive chickens was used to map the environmental contamination with this parasite. A questionnaire was applied to obtain data on the presence and management of cats and the type of water consumed. Of the farms studied, 64.7% were found to be located in areas of low to medium presence of T. gondii, 27.5% in areas with a high or very high contamination level and 7.8% in non-contaminated areas. Additionally, 70.6% kept cats, 66.7% were near water sources and 45.0% were in or near dense vegetation. Humans used untreated water for drinking on 41.2% of the farms, while all animals were given untreated water. The intensity of environmental T. gondii contamination was significantly higher on farms situated at a distance >500 m from water sources (P=0.007) and near (≤500 m) dense vegetation (P=0.003). Taken together, the results indicate a high probability of T. gondii infection of humans and animals living on the farms studied. The kernel density estimator obtained based on the frequency of chickens testing positive for T. gondii in the mouse bioassay was useful to map environmental contamination with this parasite.