Seroprevalence of varicella zoster and rubella antibodies among rural populations of the Chaco region,south-eastern Bolivia

OBJECTIVE: To determine the seroprevalence of antibodies against varicella zoster virus (VZV) and rubella virus among the population of two rural areas, Camiri and Villa Montes, Chaco region, south-eastern Bolivia. METHODS: In a cross-sectional study, serum samples from randomly selected subjects were screened for VZV- and rubella antibodies using enzyme-linked immunosorbent assay (ELISA). RESULTS: The prevalence of VZV antibodies was 80% (391 of 489). No significant differences were observed between genders and study areas. The prevalence increased with age with a seropositivity rate of 21.2% in the 1-4-year-old children, 56.9% in the 5-9 age group and 83.7% in the 10-14 age group, and reached 98.2% in over 45-year olds. The prevalence of rubella virus antibodies was 76.9% (377 of 490), without significant differences between genders and study areas. Similar to the trend observed for VZV antibodies, the seroprevalence increased with age with a seropositivity rate of 18.1% in the 1-4-year-old children, 53.9% in the 5-9 age group and 78.4% in the 10-14 age group, and reached 94.7% in over 45-year-old subjects. Among the 95 women of childbearing age (15-44 years) the susceptibility rate was 11.6%. CONCLUSIONS: A common seroimmunological profile was evidenced for the two infections. The age-specific profile of VZV seropositivity differs from that reported for other tropical countries where higher median age of seroconversion and lower seroprevalence among adults are observed. Data concerning the prevalence of immunity to rubella may be useful to evaluate the impact of the recently introduced rubella immunization programme.