Diagnosis of the difficulties of congenitally deaf children in arithmetic reasoning

This paper examines the difficulties of arithmetic reasoning of hearing impaired children and to determine the value of remedial teaching.

Contingencies of contingent employment: psychological contract, job insecurity and employability of contracted workers

Drawing on psychological contract literature, the present study examines the emerging contingent employment relationships, which involve the contracted workers, the employment agency and the client organization on whose premises these employees work. This sample includes eighty-eight white-collar employees working for four Portuguese agencies. The results suggest that the perceived fulfilment of client?s obligations relates positively to the perceived fulfilment of agency?s obligations and that these constructs are independent of one another. Furthermore, as expected, we have found that the perception of job insecurity relates negatively to the fulfilment of agency?s obligations. No relationship was found between employability and the perceived fulfilment of client?s obligations. The results have implications for practitioners and future research.

Toxoplasma gondii in the peripheral blood of patients with acute and chronic toxoplasmosis

Background and aims Toxoplasmic retinochoroiditis may recur months or years after the primary infection. Rupture of dormant cysts in the retina is the accepted hypothesis to explain recurrence. Here, the authors present evidence supporting the presence of Toxoplasma gondii in the peripheral blood of immunocompetent patients. Methods Direct observation by light microscopy and by immunofluorescence assay was performed, and results were confirmed by PCR amplification of parasite DNA. Results The authors studied 20 patients from Erechim, Brazil, including acute infected patients, patients with recurrent active toxoplasmic retinochoroiditis, patients with old toxoplasmic retinal scars, and patients with circulating IgG antibodies against T gondii and absence of ocular lesions. Blood samples were analysed, and T gondii was found in the blood of acutely and chronically infected patients regardless of toxoplasmic retinochoroiditis. Conclusions The results indicate that the parasite may circulate in the blood of immunocompetent individuals and that parasitaemia could be associated with the reactivation of the ocular disease.

A Community-based Survey of Human Toxoplasmosis in Rural Amazonia: Seroprevalence, Seroconversion Rate, and Associated Risk Factors

IgG antibodies to Toxoplasma gondii were detected in, March-April 2004, in 65.8% (95% confidence interval, 60.8-70.8%) of 342 systematically sampled subjects 5-90 years of age (87.5% of the eligible) living in a rural settlement in Amazonia, with a seroconversion rate of 9% over I year of follow-up of 99 seronegative subjects. Multiple logistic regression analysis identified age as the only significant independent predictor of seropositivity at the baseline. Each additional year of age increases the odds of being seropositive by 6%, and 76.8% of the subjects are expected to be seropositive at 30 years of age. A single high-prevalence spatial cluster, comprising 11.9% of the seropositive subjects, was detected in the area; households in the cluster were less likely to have dogs as pets and their heads had a lower education level, when compared with households located outside the cluster. The challenges for preventing human toxoplasmosis in tropical rural settings are discussed.

Does toxoplasmosis cause DNA damage? An evaluation in isogenic mice under normal diet or dietary restriction

Toxoplasmosis is an anthropozoonotic widespread disease, caused by the coccidian protozoan parasite Toxoplasma gondii. Since there are no data regarding the genotoxicity of the parasite in vivo, this study was designed to evaluate the genotoxic potential of the toxoplasmosis on isogenic mice with normal diet or under dietary restriction and submitted to a treatment with sulfonamide (375 mug/kg per day). DNA damage was assessed in peripheral blood, liver and brain cells using the comet assay (tail moment). The results for leucocytes showed increases in the mean tail moment in mice under dietary restriction; in infected mice under normal diet; in infected, sulfonamide-treated mice under normal diet; in infected mice under dietary restriction and in infected sulfonamide-treated mice under dietary restriction. In liver and brain cells, no statistically significant difference was observed for the tail moment. These results indicated that dietary restriction and T. gondii were able to induce DNA damage in peripheral blood cells, as detected by the comet assay. (C) 2004 Elsevier B.V. All rights reserved.

Environmental risk factors for canine toxoplasmosis in a deprived district of Botucatu, SP, Brazil

Toxoplasmosis is a worldwide zoonosis caused by Toxoplasma gondii that can infect a large variety of animals, including humans. The present study aimed to evaluate the frequency of anti-T. gondii antibodies in dogs from a peripheral district of Botucatu and to establish the association among some epidemiological variables in order to evaluate risk factors for toxoplasmosis infection. Serum samples from dogs were screened using an indirect fluorescent antibody (IFA) test. Anti-T. gondii antibody prevalence was 56%. The highest titer was 1024 (1.79%) and the most frequent titers were 16 (57.14%) and 64 (33.93%). The chi-square (X-2) test revealed significant association among variables such as dog access to street, ingestion of raw meat and presence of synantropic animals in the domestic environment. These results demonstrate that toxoplasmosis is present in dogs from Jardim Santa Elisa district.

Epidemiological and Serological Aspects in Canine Toxoplasmosis in Animals with Nervous Symptoms

The presence of anti-Toxoplasma gondii IgM and IgG antibodies was studied in samples of blood serum taken from eighty dogs with nervous symptoms at the Serviço de Enfermidades Infecciosas dos Animais, Faculdade de Medicina Veterinária e Zootecnia, Unesp, Botucatu, São Paulo, Brazil. The frequency of IgG titers were 16 (13.7%), 64 (13.7%), and 256 (5%), and for IgM titers were 16 (7.5%), 64 (15%), and 256 (8.7%). Positive reactions were more frequent in the older animals, males, from a rural environment, in constant contact with small animals, principally birds and rodents. There was a higher frequency of a positive reaction in dogs fed with kitchen food, especially in those fed with raw ingredients. The most common neurological pictures were alterations in consciousness, in movement, and in the hand-cart test. The percentage of reagents with specific IgM antibodies was high, indicating active infections, but the possibility of co-infection with the distemper virus can not be discarded, and this may be a predisposing factor for toxoplasmosis infection, once the distemper virus has a potent immunosupressive action.

Perseveration in congenitally blind children: Effects of luminous and acoustic targets on a modified A-not-B task

The purpose of this study was to determine whether or not blind children perseverate during a modified Piagetian A-not-B reaching task, with conditions that employ luminous AB targets and acoustic AB targets. Ten congenitally blind children, ages 1-4 years, with residual vision for light, took part in this study. Behavioral and kinematic data were computed for participants' reaches, performed in six A trials and in two B trials, in both stimulus conditions. All of the children perseverated in the luminous condition, and none of them perseverated in the condition using acoustic targets. The children tilted their heads in the direction of the target as they reached towards it. However, this coupling action (head-reaching) occurred predominantly in the A trials in the acoustic condition. In the luminous condition, in contrast to the acoustic condition, the children took longer times to initiate the reaching movement. Also, in the luminous condition, the children explored the target surroundings, unlike the acoustic condition, in which they reached straight ahead. For these blind children, sound was more relevant to reaching than was the luminous stimulus. The luminous input caused perseveration in congenitally blind children in a similar way that has been reported in the literature for typically-developing, sighted infants, ages 8-12 months, performing A-not-B tasks with visual inputs. (C) 2012 Elsevier B.V. All rights reserved.

Clinical, parasitological and obstetric observations in pregnant bitches with experimental toxoplasmosis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Toxoplasmosis in naturally infected deer from Brazil

Serum samples from 107 cervids were examined for Toxoplasma gondii antibodies using indirect hemagglutination (IHA), indirect immunofluorescence (IFA), enzyme linked immunosorbent assay (ELISA) and Dot-ELISA. Samples were obtained from 66 marsh deer (Blastocerms dichotomus) in the State of São Paulo (Brazil) and from 41 pampas deer (Ozotocerus bezoarticus) in the State of Goias (Brazil). Antibodies to T. gondii were found in 23 (22%) of the deer, with 18 and 5 positive samples, respectively, for B. dichotomus and O. bezoarticus. The highest prevalence of T. gondii antibodies were young adults (32%), following by adults (27%) and fawns (13%). Only one serum sample (8%) from a newborn fawn was positive in the serological tests. The convenience of the Dot-ELISA test is obvious when compared with other serological tests for both laboratory or field surveys, mainly due to its features of practicability and reagent stability.

Experimental toxoplasmosis in broiler chicks

To evaluate chicken toxoplasmosis both as an economic and a public health subject, 84 broiler chicks of a commercial strain, 30 days old, were distributed into seven groups of 12 birds (three replications of four chicks) experimentally infected with three developing T. gondii stages of the P strain as follows: tachyzoites. intravenous (two groups: 5.0 x 10(5) and 5.0 x 10(6)), cysts, per os (two groups: 1.0 x 10(2) and 1.0 x 10(3)) and oocysts, per os (three groups: 5.0 x 10(2), 5.0 x 10(3) and 5.0 x 10(4)). Twelve chicks received only a placebo (control group). During the next 30 days the following parameters were estimated: productivity (weight gain and feed conversion), clinical signs, including rectal temperature and parasitemia (bioassay). No clinical signs suggesting toxoplasmosis were seen and no statistical differences on productivity standards were found in comparison between inoculated and control chicks. However, fowls inoculated with tachyzoites and oocysts occasionally showed hyperthermia. Some haematological changes were detected in fowls inoculated with T. gondii. Anatomo-histopathological changes were not observed. From 14 parasitemias detected, 35.7% appeared on the 5th day after inoculation and 57.1% of them resulted from oocysts inoculation. After 30-35 days all birds were slaughtered: fragments from 12 organs or tissues from each of them were subjected to artificial peptic digestion and after that injected into T. gondii antibody-free mice (IIFR). T. gondii was detected in brain (12), pancreas (five), spleen (five), retina (five), kidney (two), heart (four), proventriculus (three), liver (two), intestine (two), lung (one), and skeletal muscle (one). Similar to observations with parasitemia, from 42 T. gondii isolations, 59.5% came from chicks which had received oocysts. It can thus be inferred that the developing form, expelled by cats, is the most important for T. gondii chicken infection and that brain is the most infected organ in birds. Attention must be paid to the potential importance of chicken meat in public health, since T. gondii was isolated from skeletal and heart muscles. (C) 1997 Elsevier B.V. B.V.

Prevalence and risk factors for human toxoplasmosis in a rural community

Toxoplasma gondii infection may lead to important pathological questions, especially in rural areas, where several sources of infection exist. Therefore, it is important to determine risk factors in order to establish adequate prophylactic measures. The present study aimed to assess the prevalence and risk factors involved in human toxoplasmosis infection in a rural community, in Eldorado, Mato Grosso do Sul State, Brazil. This community was composed of 185 farms - with 671 inhabitants - from which 20 were randomly chosen. In these farms, blood samples were collected from rural workers, who also answered a risk factor questionnaire. Serum samples were analyzed by means of direct agglutination test for the detection of anti-Toxoplasma gondii antibodies. From 73 samples collected, 79.45% were positive. None of the studied variables was significantly associated with the prevalence of the infection. However, among the individuals who reported eyesight impairments, 94.4% had anti-T. gondii antibodies, compared with 74.0% who did not report eyesight changes (p = 0.0594). Moreover, most individuals in the study (68.20%) were older than 18 years and presented 84.44% positivity, compared with 66.67% of positive individuals younger than 18 years old. We were able to conclude that a high prevalence of antibodies did not imply significant associations with the risk factors studied.