Helicobacter pylori is a gram-negative micro-aerophilic bacterium that is widely distributed geographically and causes chronic gastritis, peptic ulcers, gastric adenocarcinoma, and mucosa-associated lymphoid tissue lymphoma. Bacterial virulence factors play an important role, since the virulent strains are more aggressive and increase the risk of developing severe clinical manifestations; in addition, other determinant factors are the nutritional state and the immune response of the host. Studies on humans, non-human primates, and rodents have reported that regulating proteins of the Th1 phenotype predominate in the immune response to the bacterial infection. The cytokines produced by this phenotype, are not very effective in eradicating the microorganism and furthermore, contribute to gastro-duodenal pathogenesis. Gastric inflammation in patients infected with H. pylori has been characterized by increased production of IL-1, IL-6, IL-12, IL-18, TNF-alpha, and IFN-gamma. Many prophylactic and therapeutic strategies have been researched using experimental animals. The utilization and effectiveness of vaccination on humans requires more study.

A fin de conocer la prevalencia de la infección por el virus de hepatitis B (VHB) en la comunidad indígena Japreira, Venezuela, y determinar las pautas de su adquisición en función de la edad y sexo, se seleccionaron 149 individuos de un total de 300. Se detectó por métodos serológicos la presencia de anticuerpos totales del VHB (anti-HBc total), y en las positivas se investigó la presencia del antígeno de superficie (HBsAg) y del antígeno "e" del VHB (HBeAg). La prevalencia de anti-HBc total fue de 72,9% en el sexo femenino y 81,1% en el masculino, la prevalencia de HBsAg fue elevada (61,1%) en el sexo masculino, sólo cuatro de los portadores de HBsAg fueron positivos para HBeAg. Los resultados obtenidos indican un grado elevado de endemia para esta infección y que su diseminación comienza a temprana edad. El factor involucrado en la adquisición y diseminación del virus seria la vía sexual. Hacinamiento, contacto intercorpóreo con fluidos biológicos, prácticas sociales, y características de la cepa viral circulante podrían estar involucradas en la alta cronicidad observada en la comunidad indígena Japreira.

Microsporidia are recognized as a cause of morbidity among patients infected with the human immunodeficiency virus (HIV). Infection rates for intestinal microsporidiosis in HIV-infected patients from Venezuela are unknown. To determine the prevalence and pathogenic role of microsporidia in these patients in northwestern Venezuela, a case control study was conducted in 103 outpatients (mean +/- SD age = 37.3 +/- 5.6 years). Microsporidia were detected using unconcentrated formalin-fixed stools examined by Weber's chromotrope-based staining method. For identification of coccidia, modified Ziehl-Neelsen carbolfuchsin staining of formalin-ether concentrates were used, and for other pathogenic parasites, iron hematoxylin-stained smears and formalin-ether concentrates were examined. Microsporidial infections were detected in 14 (13.6%) of 103 patients and 39 (37.9%) had other parasitic pathogens. No significant difference was noted in the occurrence of the infection in patients with diarrhea (13 of 74, 17.6%) and controls (1 of 29, 3.4%) (P = 0.118). Nevertheless, this result may be due to the small sample size (n = 14) of infected individuals. The proportions of other pathogens in patients with or without diarrhea were not significantly different (P = 0.828). Microsporidiosis is common among the HIV-infected population in northwestern Venezuela. However, its pathogenic role in these patients is uncertain and warrants further investigation.

Previous studies have not found hepatitis C virus (HCV) infection in Amerindians from

This study shows a very low prevalence of infection with hepatitis C virus in populations at risk for acquiring the infection, and considered that this infection is not a public health problem in these populations in Maracaibo, Venezuela.