Aristeu Vieira da Silva

Prevalence and risk factors associated to infection by Toxoplasma gondii in ovine in the State of Alagoas, Brazil

The aim of this study was to evaluate the prevalence of anti-Toxoplasma gondii antibodies and to identify risk factors associated to the infection in the three meso-regions of the State of Alagoas, Brazil. A total count of 23 towns and 27 meat sheep farms were visited where blood samples were collected in order to perform the indirect immunofluorescence test to evaluate the antibodies presence. Questionnaires exploring the production system and nutritional, sanitary, and reproduction handling were handed out. The prevalence rate was 32.9% and the number of foci was 100%. In the multivariate statistical analysis, there was a significant association for the following variables: age (OR = 4.01; C.I. 2.03–7.94), size of the property (or the farm; OR = 0.48; C.I. 0.26–0.90), semi-intensive rearing system (OR = 3.17; C.I. 1.24–8.13), running water source (OR = 3.13; C.I.–1.66–5.87), and presence of cats (OR = 1.72; C.I. 1.08–2.75). It is concluded that sheep of the three meso-regions of the State of Alagoas are exposed to the infection caused by T. gondii with high prevalence. Control and prophylactic measures must be adopted seeking the improvement of the rearing system and the implantation of health promoting programs in cooperation with sheep farmers in order to elucidate the transmission means of this disease.

Chronic infection with Toxoplasma gondii causes myenteric neuroplasticity of the jejunum in rats

Toxoplasma gondii is an aetiological agent of toxoplasmosis, which commonly causes diarrhoea in a number of species. This observation and the parasites affinity for the nervous tissue support the theory that T. gondii infection may affect the myenteric neurons. The aim of this study was to evaluate the changes caused by T. gondii (genotype III) in the myenteric neurons of the jejunum in rats. Fifteen rats were distributed into three groups: control (CG), inoculated for 30 days (G30) and inoculated for 90 days (G90). Rats from the G30 and G90 groups received an oral inoculum with 500 oocysts from a genotype III (M7741) T. gondii strain. At 180 days of age, all animals were anaesthetised and euthanised. Whole mounts were stained by using Giemsa (total population) and NADPH-diaphorase (nitrergic subpopulation) histochemistry. Maintenance of the width, length, area and neuronal density was observed; there was neuronal atrophy in the G30 group and a tendency to hypertrophy in the G90 group. Rats inoculated orally with sporulated oocysts did not show clinical illness or macroscopic or microscopic lesions, as do the majority of animal species. Therefore, infection was confirmed by a serum agglutination test; 30 days of infection caused increased weight gain and atrophy of myenteric neurons. At 90 days post-infection, weight gain became normal, and myenteric neurons hypertrophied.

Quantitative and morphometric changes of subpopulations of myenteric neurons in swines with toxoplasmosis

The consequences of the infection caused by Toxoplasma gondii in myenteric neurons of the jejunum of swines reactive to NADH-diaphorase and NADPH-diaphorase were evaluated in this study. Ten 88-day-old mixed-breed swines (Pietrain and Wessex) were assigned into two groups: Control (n=5) and Experimental (n=5), which orally received 5000 sporulated oocysts from a genotype III T. gondii strain. After 30days, the animals were anesthetized, having part of their jejunum removed and stained with NADPH-diaphorase and NADH-diaphorase. NADPHd-p neurons (nitrergic) presented increase of the number of cells per ganglion and hypertrophy. The number of NADHd-p neurons (metabolic more active) and their nuclear area decreased.

Toxoplasma gondii genotyping in a dog co-infected with distemper virus and ehrlichiosis rickettsia

This paper reports a toxoplasmosis, ehrlichiosis and distemper co-infection in a dog with an exuberant neuropathological clinical picture. Primary involvement was discussed based on information collected in the analysis of the clinical case, such as neurological impairment, epidemiological data, poor immunoprophylactic scheme of the dog affected and the role of these diseases on immunosuppression. Canine distemper and ehrlichiosis were diagnosed based on epidemiologic data, clinical signs, hematological and cytological evaluation. Toxoplasma gondii was isolated and genetically characterized as Type I using restriction analysis (RFLP) with SAG-2 genes. Immunosuppression features of both dogs and human beings are discussed, as well as implications on animal and public health. This is the first report on toxoplasmosis, ehrlichiosis and distemper co-infection in a dog in Brazil, associated with genotyping determination of the T. gondii strain involved.

Análise morfométrica da parede intestinal e dinâmica de mucinas secretadas no íleo de frangos infectados por Toxoplasma gondii

The effects of toxoplasmosis on the intestinal wall morphometry and the dynamic of mucins secreted in the chicken ileum were analyzed. Sixteen 26-day-old, male, Cobb broiler chicks (Gallus gallus) were used and randomly divided into three groups (G1, G2 and G3). G1 received no inoculum characterizing the control group, G2 was inoculated with tissue cysts of ME49 strain of Toxoplasma gondii, and G3 was inoculated with oocytes of M7741 strain of T. gondii. After 60 days of inoculation, the animals were killed and had their ileum collected and submitted to histological processing. Tranversal cuts (4mm) were stained with Hematoxilin-Eosine (HE), Periodic Acid Schiff (PAS), Alcian Blue pH 2.5 and Alcian Blue (AB) pH 1.0. Intestinal wall increase was noticed for the animals from G2 - mostly the muscle tunic, the muscularis mucosae, and the mucous tunic, including the increase of secretion of neutral mucins. The animals from G3 presented atrophy of the intestinal wall - mostly the mucous tunic, and increase of the secretion of neutral mucins.

Toxoplasma gondii: A morphometric analysis of the wall and epithelial cells of pigs intestine

The aim of this study was to perform a morphometric analysis of the different layers of the jejunal wall and epithelial cells of pigs with toxoplasmosis. Experiments were conducted using 10, 88-day-old crossbred (Pietran x Wessex) pigs divided into two groups: control (n=5) and experimental (n=5). The experimental group consisted of animals inoculated orally with 5000 sporulated oocysts of a genotype III strain of Toxoplasma gondii. At 30 and 60 days following inoculation, the animals were anaesthetised for jejunal biopsy. The intestinal segments were processed routinely for histology. Transverse cuts (4 microm thick) were stained with haematoxylin and eosin (HE), Periodic Acid Schiff (PAS), Alcian Blue (AB), pH 2.5, and Alcian Blue (AB), pH 1.0. We observed hypertrophy of the jejunal wall, increased enterocyte height, and a decreased number of intraepithelial lymphocytes in the infected animals. There were no changes in the number of goblet cells.

Toxoplasma gondii Induces Death of Gastric Myenteric Neurons in Rats

Este estudio tuvo como objetivos cuantificar y analizar morfologicamente neuronas del plexo mienterico de las curvaturas gastricas menor y mayor del estomago glandular de ratones infectados durante 30 dias por taquizoitos de Toxoplasma gondii. Fueron utilizados 10 ratas machos distribuidos aleatoriamente en dos grupos: grupo control (GC) y grupo experimental (GE). Los animales del GC recibieron solucion salina por via oral y los animales del GE recibieron, por la misma via, 104 taquizoitos de Toxoplasma gondii de una cepa genotipo III (cepa BTU II). Tras 30 dias, se realizo eutanasia para retirar el estomago, que fue disecado bajo el estereomicroscopio para retirar la tunica mucosa y tela submucosa. Preparados de membrana fueron coloreados por la tecnica de Giemsa. La cuantificacion de neuronas mientericas se realizo con microscopia optica, con objetivo de 40X en 40 campos microscopicos para la region de la curvatura gastrica menor y 40 campos para la curvatura gastrica mayor del estomago glandular, en ambos grupos. Se midio el area del cuerpo celular de 50 neuronas mientericas de cada region en cada animal. Se verifico que la infeccion experimental cronica provocada por la cepa de genotipo III de Toxoplasma gondii en ratones, redujo la densidad de neuronas mientericas solamente en la region de curvatura gastrica menor del estomago glandular, no llevando a alteraciones significativas el tamano de las neuronas.

Morphometric analysis of the intestinal wall and the dynamic of mucins secreted in the chicken ileum infected with Toxoplasma gondii

The effects of toxoplasmosis on the intestinal wall morphometry and the dynamic of mucins secreted in the chicken ileum were analyzed. Sixteen 26-day-old, male, Cobb broiler chicks (Gallus gallus) were used and randomly divided into three groups (G1, G2 and G3). G1 received no inoculum characterizing the control group, G2 was inoculated with tissue cysts of ME49 strain of Toxoplasma gondii, and G3 was inoculated with oocytes of M7741 strain of T. gondii. After 60 days of inoculation, the animals were killed and had their ileum collected and submitted to histological processing. Tranversal cuts (4mm) were stained with Hematoxilin-Eosine (HE), Periodic Acid Schiff (PAS), Alcian Blue pH 2.5 and Alcian Blue (AB) pH 1.0. Intestinal wall increase was noticed for the animals from G2 - mostly the muscle tunic, the muscularis mucosae, and the mucous tunic, including the increase of secretion of neutral mucins. The animals from G3 presented atrophy of the intestinal wall - mostly the mucous tunic, and increase of the secretion of neutral mucins.