Deworming is not a risk factor for the development of atopic diseases: a longitudinal study in Cuban school children.

BACKGROUND: Soil-transmitted helminth (STH) infections have been suggested to protect from allergic sensitization and atopic diseases. Consequently, anthelminthic treatment would increase the prevalence of atopic disease in STH endemic populations. OBJECTIVE: To investigate the effect of deworming on allergic sensitization and atopic diseases in Cuban schoolchildren. METHODS: We followed up 108 STH positive schoolchildren aged 5-13 in six-monthly intervals for 24 months. Four consecutive groups of, respectively, 104, 56, 68, and 53 STH positive children were used as 'untreated' reference groups to assess general time trends. STH infections were diagnosed by stool examination. Asthma, allergic rhinoconjunctivitis, and atopic dermatitis were diagnosed by International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire and allergic sensitization by skin prick testing (SPT). At each time point, STH positive children were treated with one single dose of 500 mg mebendazole. RESULTS: After deworming, the frequency of asthma significantly decreased (P < 0.001) while the frequency of allergic rhinoconjunctivitis and atopic dermatitis was not affected (P = 0.129 and P = 0.751, respectively). The percentage of SPT positives temporarily increased (P < 0.001) and subsequently returned to nearly baseline values (P = 0.093). In the references groups, no change over time was observed in the proportion of children with allergic sensitization and atopic diseases (P > 0.05). CONCLUSION & CLINICAL RELEVANCE: Our results indicate that atopic diseases do not increase after anthelminthic treatment. Allergic sensitization on the other hand increases after deworming. As this increase appears only temporarily, deworming of schoolchildren does not seem to be a risk factor for the development of allergic sensitization, nor for atopic diseases.

[Vaginal trichomoniasis in a group of HIV-positive people]. / Trichomonosis vaginal en un grupo de personas VIH positivas.

A total of 132 women who received attention at the Outpatient Department of Dermatology of the "Pedro Kouri" Institute of Tropical Medicine from January to July, 1998, were studied. 64 of them were HIV carriers and 68 were sound controls. On determining the infection frequency by Trichomonas vaginalis, it was found that 15.6% and 16.1%, respectively, were parasitized by this protozoa. The diagnostic techniques used were simple direct examination of the vaginal exudate and culture in vitro. The latter proved to be more sensitive on yielding 100% of sensitivity. It was determined that 48 hours was the optimum time for reading each specimen.

[Validation in Havana City, Cuba of ENZYMEBA, an immunoassay for detecting Entamoeba histolytica in feces]. / Validación en ciudad de La Habana, Cuba, de ENZYMEBA, inmunoensayo para la detección de Entamoeba histolytica en heces.

Parasitologists from different medical institutions in Havana City carried out the external validation of ENZYMEBA, a diagnostic procedure of intestinal amebiasis developed at the "Pedro Kourí" Institute of Tropical Medicine. To this end, serial faeces specimens from 212 individuals were collected and observed on the microscope (reference test). The ENZYMEBA immunoassay (validation test) was also made. On comparing ENZYMEBA with the microscopic examination, satisfactory indexes of sensitivity and specificity were found. No cross-reactions were detected in faeces specimens, where found other parasites were present, too. Taking into account that only one faeces specimen per patient is enough for the diagnosis of intestinal amebiasis with ENZYMEBA, this procedure may be useful in studies of therapeutical efficacy and prevalence.

Identification of Angiostrongylus cantonensis in infected rats with a coagglutination assay.

The presence of Angiostrongylus cantonensis excretory secretory (ES) products was detected in the cerebrospinal fluid (CSF) of infected rats using a coagglutination assay. There was clear agglutination in 100% of CSF samples tested of the rats infected with third-stage larvae of A. cantonensis and neither of the 20 non-infected rats produced agglutination. The assay detected 250 ng/ml or more of ES products. This assay is simple, easy to perform with minimum training and requires no equipment.

[Assessment of the antibody response in patients with giardiasis]. / Evaluación de la respuesta de anticuerpos en pacientes con giardiasis.

Of 104 patients under study for giardiasis-like clinica symptoms, 101 were parasitologically positive. The presence of antibodies was shown in 99 of them, which means 96% sensitivity and 90% specificity in the indirect immunofluorescence technic. Antibody response was significantly higher (p < 0.01) in those patients with no history of the disease. A significant fall (p < 0.01) was seen in antibody titres in all patients a month after the effective treatment, as well as well as persistent positive titres in those who were not cured.

Mefloquine-halofantrine cross-resistance in Plasmodium falciparum induced by intermittent mefloquine pressure.

The study was designed to evaluate how exposure of Plasmodium falciparum to mefloquine modifies the sensitivity of the parasite to four major antimalarial drugs. A recently culture-adapted strain of P. falciparum was subjected to intermittent drug pressure at three different mefloquine concentrations (2.34, 4.68, and 9.37 ng/ml). Growth was monitored by daily evaluation of parasitemia on thin smears. Drug sensitivity tests were done weekly, using a radioisotope microdilution method. Mefloquine was removed from culture media when decreasing parasitemia was observed, and reintroduced when multiplication reoccurred. Parasite survival was inversely proportional to drug concentrations. The parasites tolerated progressively higher concentrations of mefloquine with prolonged exposure to the drug. Throughout this adaptation, the 50% inhibitory concentration for chloroquine and quinine showed no modification, but it increased considerably for mefloquine, exceeding known levels of resistance. Furthermore, a parallel increased resistance to halofantrine was observed, surpassing the normal range of sensitivity. Cross-resistance between mefloquine and halofantrine shown in this study has now been confirmed by epidemiologic in vitro surveys and clone analysis. These findings may have important in vivo consequences and eventually affect the choice of antimalarial therapy.