Michele Soares Pepe

Presence of Toxocara canis eggs on the hair of dogs: A risk factor for Visceral Larva Migrans

The close contact between dogs and humans poses a high risk of exposure to Toxocara canis eggs, which can lead to Visceral Larva Migrans (VLM) syndrome. The objective of this study was to investigate the existence of these nematode eggs on the hair of the perianal region in stray and owned dogs. Samples of hair from 104 dogs of different ages were collected: 25 (24%) were positive for T. canis eggs, with mean of 614.8 eggs per gram of hair. Puppies were responsible for 99% of the total number of eggs. The ages of the animal and hair length were factors that influenced the intensity of the observed eggs. This study showed that dog hair contaminated by T. canis eggs in different developmental stages represents a potential source of VLM infection for humans.

Seroprevalence of Toxocara Infection in Children from Southern Brazil

Abstract: The seroprevalence of Toxocara canis antibodies in children aged from 1 to 12 yr old was evaluated in Pelotas City, Rio Grande do Sul, Brazil. Human toxocariasis or visceral larva migrans (VLM) was diagnosed with the use of an ELISA based on the T. canis excretory–secretory (TES) antigens; Western blotting was used to confirm the ELISA-positive results. From 427 samples, 50.6% were positive for the presence of anti-TES antibodies. A confirmatory test (Western blot) was carried out on a sample of the ELISA-positive sera (n = 70), and all were positive. The Western blots had specific banding pattern characteristics, where the 30-kDa fraction demonstrated the highest reactivity. This fraction could be important for the specific diagnosis of toxocariasis.

Vertical transmission of Toxocara canis in successive generations of mice

Visceral toxocariasis is a neglected zoonosis caused by Toxocara canis larvae in unusual hosts. In dogs, the definitive host, the infection occurs mainly through transplacental and transcolostral transmission. Studies on experimental models have shown that vertical transmission may result from acute infections. Considering that toxocariasis is characterized as a chronic infection, with possible reactivation of larvae present in the brain, this study evaluated the presence of larvae in the brain of female BALB/c mice and their offspring with chronic infection during three successive pregnancies. ELISA-TES was used to evaluate the antibody levels. T. canis larvae were detected in the brain tissue of the mice during the three successive generations evaluated. The offsprings IgG level gradually decreased, and mean absorbance (ABS) above the cutoff point (0.070) was observed only at 30 (0.229) and 50 (0.096) days of age, while IgM was not detected. The infections in the offspring confirmed that vertical transmission of T. canis larvae occurred during chronic toxocariasis in three successive generations of mice.

Determination of IgG avidity in BALB/c mice experimentally infected with Toxocara canis

Toxocariasis is a zoonotic disease in that IgM titers can remain high for long periods making difficult to determine the stage of the disease. The aim of this study is to investigate the applicability of indirect ELISA, associated with urea, to discriminate between the acute and chronic toxocariasis. IgG avidity was evaluated in 25 BALB/c mice experimentally infected with 1000 Toxocara canis eggs. Blood samples were collected, and sera treated with 6 M urea and assayed by ELISA every two weeks. The percent IgG avidity was determined using the mean absorbance of sera treated with urea, divided by the mean absorbance of untreated sera. In the first 15 days post-inoculation, was observed a low percentage, between 7.25 and 27.5%, IgG avidity, characteristic of an acute infection. After 60 days of infection, all the mice showed between 31.4 and 58% IgG avidity, indicating a chronic infection.

Biomphalaria molluscs (Gastropoda: Planorbidae) in Rio Grande do Sul, Brazil

The present study was aimed at characterising Biomphalaria species using both morphological and molecular (PCR-RFLP) approaches. The specimens were collected in 15 localities in 12 municipalities of the southern region of the state of Rio Grande do Sul, Brazil. The following species were found and identified: Biomphalaria tenagophila guaibensis, Biomphalaria oligoza and Biomphalaria peregrina. Specimens of the latter species were experimentally challenged with the LE Schistosoma mansoni strain, which showed to be refractory to infection.

SERODIAGNOSIS OF VISCERAL LARVA MIGRANS IN CHILDREN OF SOUTH OF BRAZIL.

Abstract The seroprevalence of T. canis antibodies in children from one to 12 years old was evaluated in Pelotas city, Rio Grande do Sul, Brazil. The evaluation of visceral larva migrans (VLM) was performed using an ELISA with T. canis secretory antigens (TES). Western blot was used to identify the banding profiles of positive sera within the ELISA results. From the 427 samples, 50.6% had anti-TES antibodies above the cutoff (0.270). Statistically significant differences were observed among the ELISA positive children relating to contact with dogs and cats. The ELISA positive sera and Western blots had banding pattern characteristics, where a fraction at 30 kDa had a higher reactivation. This fraction could be important for a specific diagnosis of VLM.

PRESENÇA DE COCCÍDIOS E OUTROS ENTEROPARASITOS EM UMA POPULAÇÃO DE CRIANÇAS NO MUNICÍPIO DE RIO GRANDE, RIO GRANDE DO SUL, BRASIL

Intestinal parasites are still common parasitic diseases in our country, and it is believed that the frequency of intestinal coccidia is underreported because of the rarity with which specific tests for the diagnosis of these protozoa are adopted. Therefore, this study aimed to investigate the prevalence of intestinal parasites in the population of a day care center in Rio Grande (RS), particularly the intestinal coccidian prevalence. Of the 165 preschool children examined, 106 were positive. The prevalent parasites were Giardia lamblia (30.3%) and Trichuris trichiura (24.2%), however Cryptosporidium spp. and Cystoisospora belli were found as well. These findings indicate the need for implementation of educational measures and diagnostic techniques that aim to diagnose different protozoa.