Effects of serum from neurocysticercosis patients on the structure and viability of Taenia solium oncospheres.

Neurocysticercosis, caused by Taenia solium, is arguably the most common parasitic disease of the central nervous system. In taeniid infections of nonhuman mammals, there is strong evidence of immunity in the intermediate host to the invasive larvae (oncospheres). This immunity, which is mediated by antibody and complement, has been exploited to develop vaccines that effectively prevent infection. To examine the immune response in humans, T. solium eggs were hatched and activated in vitro. Activated oncospheres were incubated with heat-inactivated sera from patients with neurocysticercosis with or without complement (guinea pig serum). Controls included oncospheres plus complement alone, normal human serum alone, normal serum with complement, or buffer alone. Serum from infected patients, especially with complement, markedly reduced oncosphere mobility and led to disappearance of secretory vesicles and loss of membrane integrity. Viability as assessed by staining with dimethyl-thiazolyl-diphenyl-tetrazolium was reduced from 92.5% in controls to 61.5% with immune serum and 38.8% with immune serum and complement (P < 0.01). Preliminary western blot analysis showed antigens at 22, 64, and 70 kDa recognized by all 3 sera, but not by control sera. These data suggest that sera from patients with cysticercosis can kill oncospheres in vitro and may be used to identify protective antigens.

Taenia solium taeniasis and neurocysticercosis in a Mexican rural family.

A case of neurocysticercosis in a six-year-old Mexican boy and a case of Taenia solium taeniasis in his five-year-old brother are reported. Neurocysticercosis was suspected based on clinical findings and was confirmed by computed tomography scanning. A parasitologic examination with zinc-sulfate flotation and formalin-ether sedimentation techniques was carried out on the whole family, and revealed Taenia sp. eggs in three stool samples from the five-year-old boy. The entire family agreed to undergo chemotherapy with niclosamide, but only the child passing taeniid eggs eliminated T. solium. No additional taeniasis cases were found in an examination of 20% of the village population, using the same parasitologic techniques. The results of an ELISA using cysticercus antigens were negative for the boy with neurocysticercosis, for other family members, and for 24 village volunteers, but were positive for the T. solium tapeworm carrier. It was concluded that in this family, person-to-person transmission of the tapeworm occurred due to poor living conditions and hygiene.

[Taeniasis, amebiasis and other intestinal parasitosis in school age children from Michoacan State, Mexico]. / Teniasis, amibiasis y otras parasitosis intestinales en niños de edad escolar del Estado de Michoacán, México.

92.3% schoolchildren aged 6-13 years of a mexican rural village, suspected foci of Taenia solium cysticercosis were screened for intestinal parasites with the main purpose to know the infection rate by taeniasis. An stool sample was collected to schoolchildren of the village and 95.4% of a urban private school as comparative group. Laboratory examinations were performed with the most accurate technics, included microscopies with an ocular micrometer. The general parasitation rate was 4 times higher in the rural village, but the percentages of Taenia spp. infection were 0.6% both of them. Entamoeba histolytica was observed 1.8% and 7.2% in the city and rural village, respectively. All the cases with taeniasis passed T. saginata after treatment with niclosamide. Negative results were obtained with the same chemotherapy in a randomly selected group of 112 schoolchildren which previous stool examination was reported negative. Neither taeniasis were demonstrated in 94 adult persons. These data are suggestive of the great variability on the transmission rates of T. solium cysticercosis in endemic areas and illustrate the faced methodological problems to confirm the diagnosis of taeniasis. By other hand support the hypothesis that estimates of infection rates with E. histolytica have been overdiagnosed in the country. Taeniasis-cysticercosis; schoolchildren; Taenia saginata; amebiasis.

Taenia solium taeniasis and cysticercosis in a Mexican village.

One hundred and twenty-four persons, nearly the entire population of a rural village in Hidalgo State, were screened for intestinal parasites and clinical or serologic (ELISA) evidence of Taenia solium cysticercosis. Heads of households were questioned about dietary and other practices that might lead to pork tapeworm transmission, and soil samples were examined for helminth eggs. Twenty-five percent of local pigs had cysticerci visible by examination of the undersurface of their tongues. Four persons passed taeniid eggs, 7 were seropositive, and 10 gave medical histories suggestive of neurodysticercosis. Most seropositive persons were not symptomatic and the reverse was also true. The clustered distribution of infected pigs, tapeworm carriers, and persons with serologic or clinical evidence of cysticercosis suggested intrahousehold transmission. Dietary and sanitary practices were generally optimal for transmission of pork tapeworm. No cattle were kept in the village and beef was rarely eaten. This preliminary report attempts to characterize T. solium transmission in communities with endemic disease in rural Mexico and illustrates some of the methodological problems faced by epidemiologists who study this disease.

Las geohelmintiasis en México y perspectivas de su control / Helminthiasis in Mexico and perspectives of its control

Se presentan datos sobre la frecuencia y distribución de las helmintiasis transmitidas por el suelo en México, haciendo notar que en algunos poblados es mayor de 90%. El autor hace notar algunos comentarios acerca del impacto socioeconómico de las helmintiasis y expone los puntos generales de la estrategia para un programa de control, enfatizando la importancia de la educación higiénica y la motivación que debe hacerse en las comunidades para lograr su participación. Se propone que un programa de esta natureza puede constituir la puerta de entrada para otras actividades relacionadas con la atención primaria a la salud

[Necator americanus uncinariasis in an infant born and residing in Mexico City]. / Uncinariasis por Necator americanus en un lactante originario y residente de la ciudad de México.

A six-month-old infant is reported with the unquestionable diagnosis diagnosis of Necator americanus uncinariasis. The mother was also infected with the same hookworm. The patient was born and has always dwelt in Mexico City, where helminthiasis is considered extremely rare. The epidemiologic studies determined that the dwelling conditions were inadequate for the transmittal of the agent through the soil. The authors emphasize the importance of the presumptive diagnosis in those cases suggesting the disease and to carry out studies to confirm the existence of other infectious means

Uncinariasis por Necator americanus en un lactante originario y residente de la ciudad de Mexico. / Uncinariasis due to Necator americanus in an infant native and living in Mexico city

Se comunica el caso de un nino de seis meses de edad con diagnostico confirmado de uncinariasis por Necator americanus y cuya madre estaba infectada tambien con este parasito.El paciente nacio y residio siempre en la Ciudad de Mexico donde se considera que la helmintiasis es muy rara. El estudio epidemiologico senalo que las condiciones de la vivienda eran inadecuadas para la transmision del agente a traves del suelo. Los autores enfantizan la importancia del diagnostico presuntivo en casos que sugieran el padecimiento y en efectuar estudios que aclaren la existencia de otros mecanismos de infeccion

[Liver hydatidosis in an eight-year-old child]. / Hidatidosis hepática en un niño de ocho años de edad

The first pediatric case of hepatic hydatidosis diagnosed in Mexico is reported. Previous to surgery, the diagnosis was established, based on a cystic tumor of the liver, the X ray findings, defects in the liver uptake, eosinophilia and Casoni's positive intradermal reaction. Besides, the immunoelectrophoresis test showed specific antibodies. Clinical and epidemiological considerations, related with the pathology and treatment of hydatidic disease are made, stressing the importance to know the symtoms of the illness, in order to establish the diagnosis and treatment. Likewise, the prognosis is evaluated considering the remaining cysts of the liver and the possible seeding of the parasite into the peritoneal cavity. Pertinent literature on the subject is reviewed.