Lack of in vitro interference between SA-11 rotavirus and attenuated poliovirus type 1.

To determine if rotavirus interferes with the multiplication of poliovirus, and hence the efficiency of the polio vaccine, the effect of timing and concentration of Simian rotavirus (SSA-11) on polio-1 infection in MA-104 cells was studied in vitro by evaluating the cytopathic effect, the reduction of the infectivity titers and the visualization of viral particles by electron microscopy. We found that poliovirus 1 was able to replicate when the challenge dose was administered within the first 8 h following SA-11 infection and with titers ten times lower than those of rotavirus. Hence, non-interference effect was observed in this in vitro model.

[Hepatitis B and delta: the prevalence of seroepidemiological markers in volunteer blood donors and their families]. / Hepatitis B y delta: prevalencia de marcadores seroepidemiológicos en donadores de sangre voluntarios y su grupo familiar.

41 volunteer blood donors and his relatives were studied in order to know about the prevalence of hepatitis B and D virus infections in selected groups. Frequency of HBsAg+ carriers was 0.34 per cent in the Centro Nacional de la Transfusión Sanguínea and 0.15 per cent in the Banco Central de Sangre, IMSS. Most of the HBsAg+ blood donors were 21 to 40 years old (87.8%); 21.9 per cent had IgM antibodies against HBc and just 2.4 per cent were HBeAg positive. Forty one (26.9%) of 152 relatives had one or more of the HBV markers, 3.9 per cent were HBsAg carriers and 1.3 per cent were HBeAg positive. In the infected relatives group 36.6 per cent were ancestory or brothers and just 14.6 per cent of wives were infected. None of the HBsAg+ blood donors or his relatives had antibodies against delta agent. These results support the fact that the frequency of asymptomatic carriers of HBsAg in the volunteer blood donors group is similar to he frequency in the general population and identifies the group of relatives as those with the highest risk to acquire HBV infection.

[The seroepidemiology of rubella in Mexican women. A national probability survey]. / Seroepidemiología de la rubéola en mujeres mexicanas. Encuesta nacional probabilística.

A rubella seroepidemiologic survey was carried out in a rural population to better understand the epidemiology of this infections disease in Mexico. 24,331 serum samples from women between 10 and 44 years old were collected during 1987-1988 from the 32 federal states. Samples were tested for Rubella Antibodies by use of hemagglutination inhibition with a titer 1:8 bring considered as positive; 79.96 per cent (CI 95%, 7.5-80.5%) of women were seropositive, seropositivity increased with age, from 69.26 per cent in the age group of 10 to 14 years old, to 87.84 per cent in the 40-44 age group. Seropositivity rates were lower in southern states than in northern states and, higher in urban areas that rural areas (82.4 vs 76.6%); statistical significative difference in seropositivity rates were found between girls less than 14 years of age in urban areas as compared to rural areas (74.7 vs 63.6%). Seropositivity rates were related to socioeconomic status only when high status group were compared lower status group (82.5 vs 77%). In addition, we observed a significative trend of increasing seropositivity as level of school education increased. In comparison to the 1974 national survey, this seroepidemiological survey showed a decreased seropositivity for all age groups, even with an increase in the number of susceptible women, particularly in the group less than 20 years old. This study offers seroepidemiologic information about rubella at a national and regional level.

Investigacion de la etiologia del brote de conjuntivitis hemorragica en la ciudad de Cancun (Mexico). / Research on the etiology of hemorrhagic conjunctivitis outbreak in the City of Cancun (Mexico)

Se estudiaron 31 pacientes de la Ciudad de Cancun, Quintana Roo, que presentaban conjuntivitis hemorragica aguda (CHA) con objeto de identificar el agente etiologico de este brote epidemico. Se aislo un agente viral en ocho cultivos de celulas WI38 inoculadas con exudados o raspados conjuntivales. Al observar estos cultivos al microscopio electronico, se encontraron particulas virales con simetria cubica de 26 a 29 nm (picornavirus).Se demostro la elevacion en el titulo de anticuerpos o bien la presencia de estos a titulo elevado en diez sueros pares de los pacientes con CHA al ser desafiados contra la cepa J 670/71 del enterovirus 70. Los estudios citologicos del raspado conjuntival mostraron celulas con cuerpos de inclusion caracteristicos de una infeccion viral. Con estos resultados se demostro que la CHA de Cancun fue originada por el Enterovirus 70

Comparacion de las tecnicas de electroforesis del RNA viral, ELISA y fijacion de complemento con la microscopia electronica para demostrar rotavirus. / Comparison between viral RNA electrophoresis, ELISA and complement fixation technics with electron microscopy to demonstrate rotavirus

Ya que la microscopia electronica (ME) es una tecnica laboriosa y requiere de equipo especializado, hemos efectuado este trabajo con la finalidad de encontrar otras tecnicas que presenten buena sensibilidad, bajo costo y facilidad de realizacion. Se estudiaron 138 muestras de materia fecal de ninos con gastroenteritis, para buscar rotavirus por medio de la ME,electroforesis del RNA viral (ELEC), fijacion del complemento (FC) y ELISA. Se demostraron rotavirus por ME en 35 muestras (25.3 por ciento); de estas, 25 resultaron positivas por ELEC. Todos los casos negativos por ME tambien lo fueron por ELEC. Todos los casos positivos por ME tambien lo fueron por ELISA; sin embargo; la intensidad de la reaccion vario notablemente. De las 103 muestras negativas por ME, 84 (81.6 por ciento) se calificaron como negativas o +/-; 19 (18.4 por ciento) se calificaron con + o ++, y no hubo ningun caso con +++ o ++++. Por medio de la tecnica de fijacion del complemento no hubo correlacion entre la positividad y la presencia de rotavirus en materia fecal. Consideramos de mayor sensibilidad ELISA y luego ELEC, y sin utilidad FC