RESUMO
Dengue is a significant health concern in Sri Lanka, but diagnosis of the infecting dengue virus (DENV) serotype has hitherto been largely restricted to the Colombo district in the western province. Salinity tolerant Aedes vectors are present in the island's northern Jaffna peninsula, which is undergoing rapid groundwater salinization. Virus serotypes were determined by RT-qPCR in 107 and 112 patients diagnosed by NS1 antigen positivity from the Jaffna district in 2018 and 2019, respectively, and related to clinical characteristics. DENV1 and DENV2 were the most common serotypes in both years. Infections with multiple serotypes were not detected. DENV1 was significantly more prevalent in 2019 than 2018, while DENV3 was significantly more prevalent in 2018 than 2019 among the Jaffna patients. Limited genomic sequencing identified DENV1 genotype-I and DENV3 genotype-I in Jaffna patients in 2018. Dengue was more prevalent in working age persons and males among the serotyped Jaffna patients. DENV1 and DENV2 were the predominant serotypes in 2019 in the Colombo district. However, DENV1 and DENV3 were significantly more prevalent in Colombo compared with Jaffna in 2019. The differences in the prevalence of DENV1 and DENV3 between the Jaffna and Colombo districts in 2019 have implications for dengue epidemiology and vaccination. Salinity-tolerant Aedes vector strains, widespread in the Jaffna peninsula, may have contributed to differences in serotype prevalence compared with the Colombo district in 2019. Significant associations were not identified between virus serotypes and clinical characteristics among Jaffna patients.
RESUMO
Objective:To determine the seroprevalence of varicella zoster virus (VZV) antibodies among the population residing in the Colombo district of Sri Lanka.Methods:A cross-sectional population-based study was conducted which included 1 258 participants. Blood samples were collected and questionnaires administered to obtain sociodemographic information and history of varicella and/or herpes zoster. Serum samples were assayed for VZV IgG antibodies using a commercial enzyme-linked immunosorbent assay kit.Results:Overall, the seroprevalence was 54.2% (95% CI = 51.5% 57.0%). Children below 1 year of age were seronegative, and only about 20.0% of children between 1 and 10 years of age were seropositive. Seropositivitiy increased with age and by the age of 40 years 74.3% were seropositive. Among women of childbearing age, the overall seroprevalence was about 62.0% (95% CI = 57.7%-66.1%) but was low 37.0% in the 15-19 age group.ConclusionIn this population, 45.8% lacked natural immunity against varicella. Of women of childbearing age, 39.9% lacked immunity and in the subgroup of women 15-19 years of age, 63.0% women lacked immunity. In light of the country's success with the control and high coverage of other vaccine preventable diseases and that the vaccine is available in the private sector, the inclusion of varicella vaccine in the national immunization program may be considered.
RESUMO
Objective: To determine the seroprevalence of varicella zoster virus (VZV) antibodies among the population residing in the Colombo district of Sri Lanka. Methods: A cross-sectional population-based study was conducted which included 1 258 participants. Blood samples were collected and questionnaires administered to obtain sociodemographic information and history of varicella and/or herpes zoster. Serum samples were assayed for VZV IgG antibodies using a commercial enzyme-linked immunosorbent assay kit. Results: Overall, the seroprevalence was 54.2% (95% CI = 51.5% 57.0%). Children below 1 year of age were seronegative, and only about 20.0% of children between 1 and 10 years of age were seropositive. Seropositivitiy increased with age and by the age of 40 years 74.3% were seropositive. Among women of childbearing age, the overall seroprevalence was about 62.0% (95% CI = 57.7%-66.1%) but was low 37.0% in the 15-19 age group. Conclusion: In this population, 45.8% lacked natural immunity against varicella. Of women of childbearing age, 39.9% lacked immunity and in the subgroup of women 15-19 years of age, 63.0% women lacked immunity. In light of the country's success with the control and high coverage of other vaccine preventable diseases and that the vaccine is available in the private sector, the inclusion of varicella vaccine in the national immunization program may be considered.