Ultrastructural damage of Trypanosoma cruzi epimastigotes exposed to decomplemented immune sera.

The susceptibility of Trypanosoma cruzi epimastigotes to lysis by normal or immune sera in a complement-dependent reaction has been reported, but the effects induced directly by immune serum depleted of complement remain unstudied. The aim of this work was to study the ultrastructural alterations induced in T. cruzi epimastigotes by immune mouse or rabbit sera with or without complement. A local isolate of T. cruzi (Queretaro) was used in all experiments. Immune sera were raised in both mouse and rabbit by immunization with T. cruzi epimastigote antigens. Light microscopy showed intense agglutination of epimastigotes when incubated with decomplemented mouse or rabbit immune sera. A distinctive ultrastructural feature of this agglutination pattern was the fusion of plasma membranes and a pattern of intercrossing between subpellicular microtubules. Agglutination was associated with fragmentation of nuclear membranes and swelling of cytoplasm, Golgi cisternae, endoplasmic reticulum, mitochondria and kinetoplast membranes. Agglutinated parasites also incorporated trypan blue stain. Results of [3H]-thymidine incorporation confirmed that epimastigotes exposed to specific antibodies in the absence of complement were incapable of proliferating. Ultrastructural changes observed in epimastigote micrographs incubated with decomplemented immune mouse sera were statistically significant (P<0.001) when compared with results obtained from images after incubation with decomplemented normal mouse sera.

Nitazoxanide for the treatment of intestinal protozoan and helminthic infections in Mexico.

A study to evaluate the efficacy and safety of nitazoxanide as a single agent for the treatment of a broad spectrum of mixed parasitic infections, both protozoa and helminths, was conducted at a primary school in San Pedro Tolimán, Querétaro, Mexico. Three faecal samples from 1824 adults and children were screened for the presence of oocysts, cysts, trophozoites, eggs or larvae of intestinal protozoa or helminths. Two hundred and forty-six adults and children infected with at least one protozoan and 2 helminths were given 7.5 mg/kg of nitazoxanide (500 mg to adults and 200 mg to children less than 12 years old) every 12 h for 3 consecutive days. Faecal samples were examined on days 6, 7, 8, 13, 14 and 15 (+/- 1) following initiation of treatment, using formalin-ether concentration and Kato-Katz egg counting. Treatment with nitazoxanide was 71-100% effective in eliminating evidence of infection with Entamoeba histolytica/E. dispar, Giardia duodenalis, Blastocystis hominis, Isospora belli, Enterobius vermicularis, Ascaris lumbricoides, Trichuris trichiura and Hymenolepis nana. Haematology and clinical chemistry values obtained before and after treatment remained unaffected by nitazoxanide. The drug was well tolerated, with only 15 patients (6.1%) reporting mild abdominal pain that lasted less than 24 h.