[The cohort study on HFRSV antibody variation in normal population of an epidemic area]

We randomly selected 2,796 persons in an epidemic area of HFRS in Anhui province for serological study from April to December in 1988. The results showed that the antibody prevalence rates were 7.3%, 10% and 14% respectively in April, September and December. Their GMT were 1.30, 1.42 and 1.73 respectively. Indoor rodent density and HFRSV carrying rate were respectively 7.8%, 6.4% in April, 9.4%, 8.8% in September, and 7.5%, 8.2% in December. Outdoor rodent density and HFRSV carrying rate were respectively 10.0%, 6.8% in April, 29.5%, 12.2% in September, and 10.8%, 11.0% in December. The positive seroconversion rate was 6.0% and negative seroconversion rate was 18.0%. The ratio of clinical infection to subclinical infection was 1:26. It is conclude that subclinical infection is dominant in HFRS infection, outdoor rodent density and their HFRSV carrying rate are the main factors for the infection in this HFRS endemic area.