Nilda Ester Radman

Human toxocarosis. Its seroprevalence in the City of La Plata

Toxocara canis is very common in dogs throughout the world. It is the primary cause of visceral larva migrans (VLM) in humans. Soil contaminated with T. canis embryonated eggs is the main source of infection of man. Our objective was to describe Toxocara seroprevalence in humans in the city of La Plata associated with some determinants such asage, presence or absence of clinical manifestations and risk factors. Blood samples were collected at random from 156 patients of different sex and age, with and without clinical symptoms compatible with the disease. The diagnostic technique ELISA test was performed with the Bordier Affinity Products Commercial Kit, using excretory-secretory Toxocara antigen with a sensitivity higher than 90%. The values were positive in 39% of the studied population. In the analysis according to age, the younger group presented significant differences with respect to the older one (Chi-square p<0.05). Positive patients presented clinical symptoms compatible with the disease (84%), and 41% presented some risk factor. The level of positivity obtained indicates a certain risk of being infects mainly in patients younger than 15 years old. The authors agree that an early identification and treatment of VLM may save a life.

Contaminación de suelos con huevos de Toxocara sp. en plazas y parques públicos de la ciudad de La Plata. Buenos Aires, Argentina

This study consisted of a stratified sampling, randomly taken, of the soil from the squares and parks of the city of La Plata, Province of Buenos Aires, in order to establish the prevalence of contamination caused by Toxocara sp. A total 242 soil samples was examined. From each sample a 10 grams aliquot was taken, washed in a 0.2% Tween 80 solution, and processed using the technique of concentration by flotation with sugar solution. There was a prevalence of 13.2%. In each positive sample, the quantity of eggs varied from 1 to 4. Toxocara sp. eggs were observed in 15 out of 22 squares and parks investigated. The sampling design and the processing method employed were satisfactory for the recovering and identification of Toxocara sp. eggs

Toxocara canis: migración larval y eosinofilia en el hospedador paraténico

The objective of this study was to analize the migratory behaviour of larvae of Toxocara canis related to eosinophilia in paratenic hosts. Mice were used as experimental models. In rodents and humans the migratory route and the pathogenesis of the parasite are similar. Balb/c mice were inoculated intragastrically with 250 (± 10) embryonated eggs. Larvae recovery: eyes and encephalon were chosen as reference organs. In the encephalon and the eye, larval recovery began in the forth and twelfth day post-inoculation respectively. The association measured by the correlation coefficient between time of observation and recovered larvae in each organ was: right eye (RE) r= 0.24; left eye (LE) r= 0.43; encephalon (E) r= 0.60. The recovery of inoculated larvae is significantly higher in the encephalon than in the eyeballs (Chi square: 185; p < 0.00001), in 80 % of mice eosinophils exceeded 6% of the formula. The correlation between eosinophilia and larval recovery in the organs observed was: 0.33 for the right eye (RE); 0.21 for the left eye (LE) and 0.44 for the encephalon; these correlation values are considered low, suggesting no association between eosinophilia and the quantity of T. canis larvae lodged in the eyes (ocular toxocarosis) or in the encephalon (cerebrospinal toxocarosis).

Toxocariasis: seroprevalence in abandoned-institutionalized children and infants

Toxocariasis is an infection that has worldwide distribution. Toxocara canis is the most relevant agent due to its frequent occurrence in humans. Soil contamination with embryonated eggs is the primary source of T. canis. This study aimed to determine the seroprevalence of toxocariasis in 10-month to 3 year-old abandoned infants, considered to be at high risk because of their orphanhood status and early age. Blood samples were collected from 120 children institutionalized in an orphanage in the city of La Plata. In this study, we observed 38.33% of seropositive cases for T. canis by ELISA and 45% by Western blot techniques; significant differences among groups A (<1 year), B (1-2 years) and C (>2 years) were also found. In research group A, children presented a seropositivity rate of 23.91%, in group B of 42.85% and in group C of 56%, which indicates an increase in frequency as age advances, probably because of greater chances of contact with infective forms of the parasite since canines and soil are frequently infected with T. canis eggs. Abandoned children come from poor households, under highly unsanitary conditions resulting from inadequate or lack of water supply and sewer networks, and frequent promiscuity with canines, which promotes the occurrence of parasitic diseases. These children are highly vulnerable due to their orphanhood status and age.

Toxocarosis neurológica: descripción de un caso clínico

La toxocarosis es una parasitosis producida por los nematodos Toxocara canis y Toxocara felis cuyos huespedes naturales son los canidos y felidos domesticos, respectivamente. La infeccion humana ocurre de manera accidental por la ingesta de huevos larvados presentes en la tierra, arena, agua o alimentos contaminados. Abarca una diversidad de presentaciones clinicas que sumadas a la inespecificidad de la sintomatologia y a la dificultad para acceder a un diagnostico de laboratorio preciso, lleva a que la mayoria de los profesionales no piensen en esta helmintiasis. El presente trabajo describe un caso clinico de toxocarosis neurologica, diagnostico, tratamiento y epidemiologia. Paciente femenino de 42 anos de edad, con historia de contacto intimo con cachorros y perras prenadas que desarrollo compromiso neurologico (paraparesia y vejiga neurogena espastica) asociada a leucocitosis con eosinofilia intensa y persistente (11.766 eosinofilos/mm3), hepatomegalia y serologia positiva a Toxocara canis determinada por ELISA y confirmada por Western-blot. Tratamiento: albendazol 400 mg/ dia cada 12 hs por via oral durante 7 dias y metilprednisona 80 mg/ dia por via oral durante 3 semanas seguida de una disminucion paulatina de la dosis. El estudio epidemiologico consistio en diagnostico serologico a convivientes de la paciente, analisis parasitologicos a las heces de sus perros y a muestras de tierra procedentes de su domicilio, resultando en todos los casos positivos para Toxocara canis.