Application of Giemsa stain for easy detection of Trichinella spiralis muscle larvae.

The application of Giemsa technique to stain compressed diaphragm samples obtained from rodents experimentally infected with Trichinella spiralis is described. Diaphragm samples from rats heavily infected with 20 muscle larvae per gram of body weight (20 ML/gbw) were cut into several pieces and stained with Giemsa; on the other hand, whole diaphragms from slightly infected mice (1 ML/gbw) were also stained with Giemsa. Besides, muscle samples were also stained with Giemsa. Observation at 10 x magnification revealed that both ML and nurse cells (NC) look as bluish structures clearly contrasting with the pinkish color of the non-infected muscle fibers. NC in the diaphragms of mice could be easily observed at naked eye as blue points contrasting with the pink surrounding areas formed by the non-infected muscle fibers. Among NC observed in the diaphragms of rats infected with 20 ML/gbw, 4.4% was multiple infection. These findings were confirmed in sectioned and hematoxylin-eosin stained specimens. This data could be usefulness for a rapid diagnosis of trichinellosis in post-mortem mammals without magnification procedures.

Prevalence of antibodies to onchocerca volvulus in residents of Oaxaca, Mexico, treated for 10 years with ivermectin.

Studies to determine the prevalence of antibodies to Onchocerca volvulus, prior to and after actions carried out to interrupt transmission, are scarce in Mexico. Here we report the prevalence of immunoglobulin G (IgG) and IgG4 antibodies in an enzyme-linked immunosorbent assay (ELISA) against a crude extract of O. volvulus adult worm in serum samples from persons under noninterrupted biannual treatment with ivermectin in areas of onchocercosis endemicity in Mexico. To perform the prevalence studies, the ELISA procedures were first evaluated. Serological studies were performed with serum samples from skin microfilaria carriers from Guatemala and from people microfilariodermic negative living in the same area as the Guatemalan patients. Sensitivity values for IgG or IgG4 detection were 71 and 86%, while specificities were 92 and 100%, respectively. No anti-O. volvulus antibodies were found in samples from nonendemic controls from Mexico, but 3 of 71 samples from residents in the onchocercosis area of Oaxaca, Mexico, and who have been under ivermectin treatment during the last 10 years were only positive to IgG. Notwithstanding that the IgG4 isotype was not detected and a low (4.2%) anti-O. volvulus IgG antibody prevalence was found, a seroepidemiological follow-up must be performed in order to confirm interruption of onchocercosis transmission in the area of Oaxaca, Mexico, in which onchocercosis is endemic.

Búsqueda de anticuerpos contra trichinella spiralis en roedores de libre desplazamiento capturados en un zoológico de la Ciudad de México / Search for antibodies against trichinella spiralis in free roaming rodents caught in a zoological park from Mexico City

A serological survey to search for antibodies against T. spiralis was performed in free roaming rats (n=64) and mice (n=35) caught in zoological park from Mexico City. Serum samples were analyzed by ELISA and immunoelectrotransfer blot assay (EIBT). None serum show positive absorbance values in ELISA nor recognized T. spiralis specific antigenic fractions in EIBT. However, two rat samples recognized three antigens of 31,37 y 55 kDa, while one of them reacted with two additional antigens of 64 and 67 kDa. As it is known that the antigen epitope profiles varied among trichinella species, it could be possible that in rats, there is 3 percent of antibody prevalence agains trichinella sp.; however, due that other organisms could induce the production of cross-reacting antibodies, such conclusion can not be supported at all. These results suggest that T. spiralis was not part of helminthological fauna in these rodents

Quimioterapia de la oncocercosis: evaluación del mebendazol solo y asociado con dietilcarbamazina / Drug therapy of onchocercosis: evaluation of mebenzole alone and in combination with diethylcarbamazine

El objetivo de este trabajo fue evaluar la eficacia del mebendazol(MEB) solo, o en combinación con dietilcarbamazina(DEC), en un estudio abierto, controlado, en pacientes infectados con Onchocerca volvulus. Se administró MEB a dosis de 50 mg/kg/día, durante 14 días a 7 pacientes con altas cuentas de microfilarias en piel. Otros 7 pacientes recebieron 2 g de MEB diarios por 14 días (promedio 44 mg/kg/día). Adicionalmente, a estos últimos pacientes, se les agregaron 3 mg/kg/día de DEC durante los últimos cuatro días de tratamiento. Los criterios para la selección de pacientes fueron: a) cuentas de microfilarias entre 15 y 100 por biopsia de piel; b) presencia de nódulos subcutáneos y c) ausencia de severo daño ocular y enfermedades sistémicas. Los resultados mostraron que la combinación de MEB más DEC fue ineficaz para prevenir las reacciones adversas causadas por la administraçäo de DEC. Esto fue debido a la ineficacia del MEB para disminuir la carga original de microfilarias en piel antes de la administración de DEC. El MEB, administrado a 50 mg/kg/día, durante 14 días, fue incapaz de inducir un descenso significativo y substancial de las cuentas de microfilarias en piel. Sin embargo, se observó una leve reducción en las cuentas de microfilarias en piel 15 días después de iniciada la administración de la droga. Los cambios más importantes a nivel ocular fueron detectados en el grupo de pacientes que recibieron MEB. Extradiordinariamente importante, fue la movilización de microfilarias observada en la cámara anterior de los ojos de los individuos que recibieron MEB sólo. Las reacciones sistémicas adversas fueron más aparentes tanto en frecuencia como en intensidad en los pacientes que recibieron MEB más DEC, que en los pacientes que recibieron MEB solo. En conclusión, MEB dado a la dosis de 50 mg/kg/día durante 14 días, fue ineficaz para disminuir las cuentas de microfilarias en pacientes infectados con Onchocerca volvulus

La oncocercosis y su relación con el aparato urinario / Onchocercosis and its relationship with urinary tract

La oncocercosis es una enfermedad parasitaria que tradicionalmente se ha considerado como un padecimiento que afecta exclusivamente a los tejifos oculares y cutáneos. Sin embargo, ya se ha demostrado que existen también otras alteraciones sistématicas, renales y neurológicas especialmente inducidas durante el tratamiento con microfilaricidas. En este artículo se hace una revisión de los aspectos renales de la oncocercosis que incluyen la presencia de microfilarias de onchocerca volvulus en orina (microfilaruria), así como de hematuria y proteinuria en pacientes infectados con esta filaria. Estas manifestaciones renales pueden observarse en oncocercosos que no se encuentran bajo tratamiento, pero su aparición es especialmente notable durante la quimioterapia tanto con microfilaricidas como con macrofilaricidas. No obstante que estas alteraciones pueden desaparecer o no después de finalizado el tratamiento, aparentemente tienen muy poca influencia en el cuadro clínico general de la oncocercosis. Se hace hincapié en los posibles mecanismos por los cuales las microfilarias de 0. volvulus pasan de los tejidos cutáneos hacia el torrente sanguíneo y, desde allí, hacia la orina. Asimismo, se comentan los mecanismos propuestos para explicar el lesión renal, mecanismos que al parecer tienen un origen inmunológico basado en el depósito de complejos inmunitarios en la membrana basal de glomérulo.

DIG-ELISA test in onchocerciasis: serum antibodies and probability of infection

An immunoenzymatic test (DIG-ELISA) was serologically evaluated for the serodiagnosis of onchocerciasis. Control and infected sera from the onchocerciasis endemic area of Mexico was collected and the donors assessed for onchocerciasis according to parasitological, clinical, and epidemiological data. The sera were submitted to the DIG-ELISA test using a crude extract prepared from O. volvulus adults woems which had been preserved in nodules in 67 percent glycerol. The test showed a 100 percent sensitivity with sera from 38 microfilariae carriers and 96 percent specificity with sera from 133 non-infected people living outside the endemic zone. In addition, seropositivity was 52.9 percent with samples from nononchocercotic people living indide the endemic area, while 82.5 and 90.5 percent of sera from patients with clinical symptoms and subcutaneous nodules, respectively, were positive. A high rate (30 percent) of cross-reactivity with serum samples from people infected with Wuchereria bancrofti or Brugia timori was obtained, which is in contrast with the low seropositivity rates (7.4 percent) obtained with sera from patients infected with other parasites. These results suggest that DIG-ELISA test may be a useful serological test for antibody detection in onchocerciasis, especially for epidemiological surveillance of disease, but because of the high cross-reactivity observed, its use must be limited to areas where this parasitic infection does not coexist with other human filiariasis. Finally, the arrangement of sera in groups according to the relative likelihood to have onchocerciasis seems to be a useful procedure for evaluation of serologicales tests