Seroprevalence of hepatitis A virus and varicella zoster antibodies in a Javanese community (Yogyakarta, Indonesia).

Hepatitis A virus (HAV) cause an acute inflammation of the liver. Varicella-zoster virus (VZV) cause chickenpox (varicella) and herpes zoster. Effective vaccines against hepatitis A and varicella are available for children, adolescents and adults. In order to implement an appropriate vaccination policy, a baseline to assess the potential benefits and sections of the population who would benefit most are required. We investigated seroprevalence of hepatitis A virus and varicella zoster antibodies in a Javanese community. A total of 1,103 subjects were studied. The 600 subjects aged 4 to 9 years were sampled between 23 October and 2 November, 1995. The other subjects were sampled between 12 October and 1 November, 1996. The overall prevalence of anti-HAV in cohort was 28.7%. Anti-HAV seroprevalence rates were below 30% until the age of 15 and below 40% until the age of 25. The anti-varicella seroprevalence showed only in two thirds of seropositive population at the age of 15. The results of the study have implications for vaccination strategies for both hepatitis A and varicella zoster.

Prevalence of hemagglutination-inhibition and neutralizing antibodies to arboviruses in horses of java.

A study was conducted to measure the prevalence of hemagglutination-inhibition (HI) and neutralizing antibodies against two arboviruses (Chikungunya and Japanese encephalitis virus) in horses of Java, Indonesia. Blood specimens were collected from a sample of 112 horses at two stables: Pulo Mas, a racing track-horse complex, located in a residential area in North Jakarta, and Pamulang, a riding school, located in a rural environment of West Jaya. Sera were tested by the HI assay and plaque reduction neutralization test. JEV antibodies were detected by HI in 58 (52%) of the horses, while only 11 (10%) had Chikungunya antibodies by HI. The proportion of Pamulang horses infected with JEV (66%) was significantly higher than found among Pulo Mas horses (40%) screened (p < 0.01). Of the 58 horses with JEV antibodies by HI, 52 (90%) were found to have specific neutralization antibodies to JEV. HI and neutralization tests on horse sera indicated that the risk to alpha virus infections was minimal in horses surveyed from Java. However, there was a high risk of JEV infection among the same population.

Comparative sensitivity of laboratory methods to diagnose dengue virus infections at Husada Hospital, Jakarta.

Several methods are available for diagnosis of dengue virus infections including a new commercially available dengue blot IgG assay. We conducted a study to compare the sensitivity of the dengue blot with the conventional diagnostic methods. Serum samples from suspected dengue patients were collected for virus isolation and the following serological assays: the hemagglutination-inhibition assay, an IgM/IgG enzyme-linked immunosorbent assay, and the dengue blot. When suspected dengue samples were tested by all methods, viral isolation detected the fewest dengue infections (10.5%), while the IgM/IgG ELISA was the most successful (46.3%) in diagnosing dengue infections. In a specific comparison between the IgM/IgG ELISA and the dengue blot, the dengue blot had an overall sensitivity of 48.8%, with a specificity of 88.7%. When patients were classified by their serological response, the dengue blot had a sensitivity of only 1.7% in those patients with a primary or recent dengue infection, however in secondary infections, the sensitivity of the dengue blot improved to 93.5%. Testing convalescent samples from patients with primary infections, only slightly changed the sensitivity of the dengue blot. The diagnosis of dengue is needed rapidly by clinicians to insure prompt treatment of patients. The dengue blot provides a rapid and easily performed assay, especially sensitive in secondary dengue infections which are most common in hospitalized cases in Asia.