Cure and reinfection patterns of geohelminthic infections after treatment in communities inhabiting the tropical rainforest of Assam, India.

Mass de-worming targeted at socio-economically poor communities can be considered as an option for communities living in the tropical forests of Assam who do not have access to safe drinking water and proper sanitation, and consequently have a higher risk of suffering from geohelminthic infection and associated morbidity. A random sample of 265 subjects was included in this study (134 males and 131 females). The chemotherapeutic regimen followed was a single dose of albendazole 400 mg. Stools samples were collected in 10% formol-saline for detection of infection before treatment. Post-treatment stool samples were collected 10 to 14 days after treatment to determine the cure rate. Stool samples were again collected 3 to 6 months post-treatment to study the rate of reinfection. Multiple logistic regression was used to find possible associations between age, sex and treatment failure. The chi-square test was used wherever appropriate. The cure rates for Ascaris lumbricoides, Trichuris trichiura and hookworms were 70.8%, 68.7% and 93.0%, respectively. Logistic regression revealed that age was associated with treatment failure in A. lumbricoides infection. Re-infection rates after 3 months of successful treatment were 19.6% for A. lumbricoides, 30.9% for T. trichiura and 11.3% for hookworms. Six months post-treatment, the prevalence of re-infection was highest with T. trichiura (43.6%); followed by A. lumbricoides (35.3%). The rate of reinfection with hookworms was lower (11.3%) six months post-treatment. The rates of re-infection with A. lumbricoides and T. trichiura was higher in children below 15 years of age, compared with adults. Hookworm reinfection was higher in the adult age group (15 to 39 years). The rates of new infection in previously uninfected subjects were lower compared with the rates for re-infection.

In vitro study on thiabendazole action on viability of Ascaris lumbricoides (Lineu, 1758) eggs

The in vitro activity of thiabendazole on Ascaris lumbricoides eggs, which were recovered from uteri of worm excreted after chemotherapeutic treatment, was studied. Four concentrations of the drug were used: 1 - 2.5 - 5 - and 10 ppm during 24, 48 and 72 hours of exposure. Subsequently, the eggs were centrifuged, washed three times and H(2)SO(4)0.1N was added. The eggs were maintained in an incubator for 20 days at 28 degrees C. Finally, the percentage of embryonated eggs was determined under a lightmicroscope at a 100X magnification. After 48 and 72 hours of thiabendazole exposure, at a concentration of 10ppm, the drug showed complete inhibition of egg embryonation.

Foi estudada, in vitro, a ação do tiabendazol, contra ovos de Ascaris lumbricoides , retirados de úteros de vermes eliminados após tratamento. Foram utilizadas quatro concentrações da droga: 1 ¾ 2,5 - 5 e 10 ppm em três diferentes períodos de tempo: 24, 48 e 72 horas. Decorridos estes tempos a suspensão com os ovos foi centrifugada, lavada por três vezes com água destilada, adicionada de solução de H2SO4, 0,1N e mantida em estufa a 28°C por 20 dias. Em seguida, os ovos foram levados ao microscópio óptico, no aumento de 100X, para observação do percentual de embrionamento. Na concentração de 10ppm, nos tempos de 48 e 72 horas de exposição à droga, verificou-se completa inibição do embrionamento dos ovos.

Antihelmínticos como factor de riesgo en la obstrucción intestinal por ascaris lumbricoides en niños / Anthelmintics as a risk factor of intestinal obstruction by ascaris lumbricoides in children

In a retrospective study the authors analyzed the clinical records of 199 children ages one month to 16 years hospitalized, with the diagnosis of intestinal ascariasis, in the Instituto Nacional de Pediatría of México from 1984 to 1999. The purpose of the study was to evaluate the use of anthelmintics drugs as a risk factor of intestinal obstruction by A. lumbricoides. Two groups were made for the study: group A (n=66) of children who presented intestinal obstruction, group B (n=133) children with no complications. A comparative analysis of clinical data of both groups was made by means of chi square with Yates correction and a stratified analysis by means of chi square. Possible confusing elements were overcrowding, age and the use of antiparasitic drugs. The calculus of risk factors for intestinal obstruction by A. lumbricoides was done by means of contingency tables of 2 x 2 and odds ratio with an IC of 95 percent. The significant risk factors were included in a model of logistic regression with an impact variable consting in the presence or absence of intestinal obstruction in order to establish a multivariate model of predictive risk at level of significance of p<0,05

Effect of albendazole and mebendazole on soil-transmitted helminth eggs.

Primary school children from Nakhon Si Thammarat Province, Thailand, on endemic area of soil-transmitted helminths, were selected for study. The infected children were divided into two groups and pair-matched according to intensity of infections: group I were given albendazole (400mg) single dose and group II were given mebendazole (100mg) twice daily for 3 days. On the day following treatment, the number of Trichuris eggs in the stool markedly increased and the egg shape was also altered. These phenomena did not occur in Ascaris infections since 100% cure rate were obtained using both drugs. Incomplete ovicidal effect of the drugs to Trichuris and Ascaris eggs were demonstrated, embryos were observed to develop within the treated eggs and they hatched after feeding them to experimental animals. In hookworm infection, albendazole stimulated the females to release more eggs after medication, but both drugs showed complete ovicidal effect upon examining the eggs from the second bowel movement.

Abscesos hepáticos por áscaris lumbricoides / Hepatic abscesses by ascaris lumbricoides

Se describen dos niños con absceso hepático por áscaris lumbricoides: una niña de 14 meses de edad, quien se internó por síndrome febril prolongado y un varón de 20 meses, quien ingresó por distensión abdominal, fiebre y eliminación de áscaris en materia fecal. Se promovió búsqueda de la localización abdominal extraintestinal de los niños parasitados por áscaris con síndrome febril. La ultrasonografía fue el método de gran utilidad

Estudio de Ascaris Lumbricoides en fase larvaria / Study of Ascaris Lumbricoides in larval phase

En este medio, las parasitosis intestinales sufrieron un incremento considerable en los últimos cinco años, destacándose Ascaris lumbricoides, que tuvo un incremento del 4 por ciento al 12 por ciento. El objetivo de este trabajo fue estudiar las condiciones de temperatura, luz, medios de cultivo, pH y distintas concentraciones de ClNa para el desarrollo de la fase larvaria de los huevos de A. lumbricoides, estado en el cual infectan al hombre. Se procesaron 400 muestras de heces, de ellas, 45 presentaron huevos de A. lumbricoides. Se centrifugaron 5ml de cada muestra positiva y a un 1 ml del sedimento se agregó 1 ml de ácido sulfúrico 0,1 N, realizándose los siguientes tratamiento: a) temperatura de 15-20 ºC con luz y en oscuridad; b) 37 ºC con luz y oscuridad; c) 4 ºC en oscuridad; d) 15-20 ºC con luz y medios de cultivo; e) 37 ºC en oscuridad y con medios de cultivo. El pH fue de 5 a 5,5. A pH menores de 5 no hubo desarrollo. El estado larvario de los huevos se obtuvo entre 10 y 14 días a 37 ºC con luz natural, prolongándose a 30-40 días a 15-20 ºC con oscuridad. Concentraciones de CINa de 0,01 molar a 0,17 molar fueron las óptimas para el desarrollo de la fase larvaria. 600 mg de mebendazol y 150 a 200 mg de albendazol lograron la letalidad de las larvas in vitro. Con luz natural y temperatura de 37 ºC desarrollaron rápidamente las fases larvarias de A. lumbricoides, estado en el cual infectan al hombre

Efficacy and safety of mebendazole in children with worm infestation

Children aged between 2-16 years, were screened for worm infestation. Fifty-five children fulfilling the inclusion criteria were included in the study. They were treated with mebendazole 100 mg twice daily for three consecutive days and followed-up for 15 days to assess cure rate and side effects. Fifty children completed the study with their stools being tested by direct smear and concentration methods and blood CBC done before treatment and at the end of the study. The cure rate for ascaris was 100% and for trichuris 75%. The drug was well tolerated and apart from mild diarrhoea occurring in 22% children, no untoward effects were reported. Nemazole [mebendazole] has shown promise and seems useful in treating children with worm infestation

Viability of Ascaris lumbricoides eggs eliminated after anti-helminthic therapy

The viability of Ascaris lumbricoides eggs passed in the feces was evaluated after treatment of patients with one of the anti-helminthic drugs (thiabendazole, levamisole, cambendazole, pyrantel pamoate, mebendazole or praziquantel). For each drug, a group of 5 children was selected and their feces collected 24 h before treatment and 24, 48 and 72 h after drug administration, except for mebendazole, with the feces being collected throughout the period of treatment. After sedimentation, the total amount of eggs from each collection was transferred to tissue culture flasks containing 10 ml H2So4 O, 1N, with the addtion of 3 drops of a miconazol solution, and incubated at 28 graus centígrados, individually, for 80 days. The flasks wee maintained open and the culture were oxigenated daily by manual agitation. On the 80th day of culture, 20-days-old albino mice were inoculated with 3,200 embryonated eggs, per os. Larvae were recovered from their lungs and hearts, on the 8th day after infection, according to Baerman's method (Morais, 1948). Thiabendazole showed 100.0% ovicidal capacity as early as 48 after treatment. Inhibition of embrionary development was observed when thiabendazole was used. This drug also had an effect on the eggs infectivity when inoculated into normal mice. No significant effect on embrionary development was observed for the other drugs tested