Immunization of young children could control hepatitis A virus (HAV) infection, but the efficacy of hepatitis A vaccines in early childhood is unknown. In a randomized, double-blind trial of a single dose of a virosome-formulated, aluminum-free inactivated HAV vaccine in Nicaragua, 274 children (age range, 1.5-6 years) received vaccine or placebo injections; 239 children seronegative for hepatitis A were included in the primary efficacy analysis. HAV infection documented by immunoglobulin M antibodies was the primary end point. Among children seronegative for hepatitis A, infection was diagnosed in 4 children in the vaccine group and 22 children in the placebo group (protective efficacy, 84.6%; 95% confidence interval, 54.7%-96.1%). All infections in children in the vaccine group occurred within 6 weeks. After 6 weeks, protective efficacy was 100% (79.8%-100%). In children in the placebo group, the incidence of HAV infection was 17.6 and that of icteric illness was 1.6 cases/100 person-years. Adverse effects were rare in both children in the vaccine group and children in the placebo group. A single dose of a hepatitis A virosome vaccine is safe and protects young children against HAV infection.

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Background and ObjectivesNicaragua is highly endemic for hepatitis A. We aimed to provide an estimate of the change in the age-specific risk of hepatitis A virus (HAV) infection based on serological data from cross-sectional and longitudinal samples collected in León, Nicaragua, in 1995/96 (n = 979) and 2003 (n = 494).MethodsThe observed age-specific prevalence of anti-HAV antibodies was correlated to the age-specific risk of infection by calculating the probability of freedom from infection at a specific age.ResultsThe proportion of seropositive children aged 1.5 to 6 years was 42% in 2003 compared to 67% in 1995/96. Estimated annual risk of infection for a 3-year old child was 30% (95% CI: 27.0%, 33.1%) in 1995 and 15.5% (95% CI: 12.4%, 19.0%) in 2003. There was good agreement between estimates based on cross-sectional and longitudinal data. The age-specific geometric mean of the quantified anti-HAV antibody levels assessed in 2003 was highest at age 4 and decreased steadily up to age 40.ConclusionsThe substantially lower risk of HAV infection in 2003 than in 1995 for young children indicates a beginning transition from high to intermediate endemicity in León, Nicaragua. Consecutive age-stratified serosurveys are useful to assess changes in risk of infection following public health interventions. The decreasing age-specific GMC of anti-HAV antibodies during adulthood in a country with endemic HAV indirectly suggests that ongoing HAV exposure in the community has marginal boosting effect on antibody levels once protective immunity has been established by natural infection.

African swine fever (ASF) is one of the most important viral diseases of pigs caused by the ASF virus (ASFV). The virus is highly stable over a wide range of temperatures and pH and can survive in meat and meat products for several months, leading to long-distance transmission of ASF. Whole blood, serum, and organs from infected pigs are used routinely as approved sample types in the laboratory diagnosis of ASF. However, these sample types may not always be available. Here, we investigated meat exudate as an alternative sample type for the detection of ASFV-specific nucleic acids and antibodies. Pigs were infected with various ASFV strains: the highly virulent ASFV Malawi LIL 18/2 strain, the moderately-virulent ASFV Estonia 2014 strain, or the low-virulent ASFV OURT/88/3 strain. The animals were euthanized on different days post-infection (dpi), and meat exudates were collected and tested for the presence of ASFV-specific nucleic acids and antibodies. Animals infected with the ASFV Malawi LIL 18/2 developed severe clinical signs and succumbed to the infection within seven dpi, while pigs infected with ASFV Estonia 2014 also developed clinical signs but survived longer, with a few animals seroconverting before succumbing to the ASFV infection or being euthanized as they reached humane endpoints. Pigs infected with ASFV OURT/88/3 developed transient fever and seroconverted without mortality. ASFV genomic material was detected in meat exudate from pigs infected with ASFV Malawi LIL 18/2 and ASFV Estonia 2014 at the onset of viremia but at a lower amount when compared to the corresponding whole blood samples. Low levels of ASFV genomic material were detected in the whole blood of ASFV OURT/88/3-infected pigs, and no ASFV genomic material was detected in the meat exudate of these animals. Anti-ASFV antibodies were detected in the serum and meat exudate derived from ASFV OURT/88/3-infected pigs and in some of the samples derived from the ASFV Estonia 2014-infected pigs. These results indicate that ASFV genomic material and anti-ASFV antibodies can be detected in meat exudate, indicating that this sample can be used as an alternative sample type for ASF surveillance when routine sample types are unavailable or are not easily accessible.

RESUMENEl vIH/SIda es un problema creciente en Nicaragua, particularmente en el occidente del país. un estudio descriptivo de corte transversal fue realizado para identificar la seroprevalencia de VIH/SIDA y las conductas de riesgo en trabajadoras sexuales y conductores de transporte pesados que circulan por el by pass de León. La muestra estuvo comprendida por 100 personas. Los participantes después de firmar un consentimiento informado por escrito se les llenó una ficha epidemiológica y se les tomó una muestra sanguínea para ser sometida a la prueba de vIH. la seroprevalencia de vIH/SIda fue 1% en conductores de transporte pesado, las conductas de riesgo más importantes fueron: no uso de preservativos, frecuencia de I.T.S. y número de compañeros sexuales. Las trabajadoras sexuales se realizan la prueba de VIH/SIDA más frecuentemente que los conductores de transporte pesado. Se concluye que de cada 50 conductores de transporte pesado que circulan por el área del by pass de león, al menos uno puede estar positivo al vIH y que las trabajadoras sexuales hacen mejor uso de la medidas preventivas para vIH/Sida.Palabras Clave: VIH, Trabajadoras sexuales, transportistas, Nicaragua. INTRODUCCIóNEl VIH fue descubierto e identificado como el agente de la naciente epidemia de SIda por el equipo de luc Montagnier en Francia, 1983. En ese mismo año se demuestra que la enfermedad podía adquirirse tanto por coito anal como vaginal. [1,2] El SIDA representa la expresión patológica final de la infección por vIH cuya capacidad para atacar los linfocitos CD4 supone la destrucción del sistema inmunitario del paciente afectado, dejándolo expuesto a la agresión de numerosas infecciones que conllevan a la muerte del enfermo [1] . El virus se transmite por contacto directo y para ello es necesaria la presencia de una cantidad suficiente de virus, como la encontrada en el semen y otros líquidos corporales tales como flujo vaginal, sangre y en menor cantidad, en la leche materna. por lo tanto, el contagio del vIH se produce por vía sexual, sanguínea y de la madre al feto o al recién nacido.[3]A finales del 2004, en el mundo el número de personas que conviven con el VIH/SIDA, se calculó en 40 millones, de las cuales 17.6 millones son mujeres, estadísticas recientes estiman que las mujeres pasaron a constituir la mitad de las personas que viven con vIH/SIda, más aún las profesionales del sexo. [4,5] En América Latina en el 2003 unas 84 mil personas fallecieron a causa del SIDA, mientras que otras 200 mil contrajeron la infección. un estudio internacional que se hizo en el 2004 indicó que la prevalencia del vIH entre profesionales femeninas del sexo varía desde menos del 1% en Nicaragua, 2% en Panamá, 4% en el Salvador y más del 10% en Honduras.