ABSTRACT Diarrheal disease caused by rotaviruses has a major global impact on childhood morbidity and mortality. In fact, rotavirus infections are the leading cause of severe gastroenteritis in infants and children affecting both, developed and developing countries. Main characteristic features of rotavirus structure and pathogenesis are briefly described with special mention to epidemiological aspects contributing to the high degree of variability of circulating strains and the potential emergence of new viruses. Characterization of these novel strains is necessary in order to better understand rotavirus evolution and keep updated databases about neutralizing antigens. The humoral and cellular immune responses that follow rotavirus infections are extensively reviewed from published data using the mouse model. According to this model, recent information emphasize the important role of CD4 T cells in protection against rotavirus infection, in stimulation of IgA antibodies secretion in the intestinal mucosa and establishment of memory responses; whereas CD8 T cells appear to play a minor role with a transient protective function, which vanish with time after primary infection. In humans, the role of antibodies and/or cellular immune responses in protection is still a matter of intense discussion since controversial results were provided by studies of innate and adaptive immunity mechanisms, in both vaccinated and naturally infected individuals. Efforts in rotavirus disease prevention have been attempted with different vaccine designs including Jennerian, “modified Jennerian” and human attenuated strain approaches. Two recently licensed which have proven to be safe and efficacious in several vaccine trials, are pivotal to the hope of reducing severe acute disease in both developed and developing countries.
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