Serological and virological studies on patients with dengue hemorrhagic fever (DHF) in Chanthaburi province, Thailand. II. Serological characteristics of viruses isolated from DHF patients using a clone of Singh's Aedes albopictus cells.

Four strains of dengue (DEN) virus were isolated using C6/36 cells, a clone of Singh's Aedes albopictus cells, from acute phase sera of DHF patients in Thailand in 1978. The isolates grown and passaged in C6/36 cells were not neutralized appreciably by standard rabbit antisera against each of the 4 types of DEN virus, but their serotypes could be identified by complement fixation (CF) tests. After the 4th or 10th passage in suckling mouse brain (SMB), however, three of the four strains showed type-specific reactions in neutralization (N) tests against the standard antisera.

Serological and virological studies on patients with dengue hemorrhagic fever (DHF) in Chanthaburi province, Thailand. I. Serological studies on paired sera from DHF patients by neutralization (N), hemagglutination inhibition (HI) and staining tests.

Twenty paired sera were collected from DHF patients admitted to the provincial hospital of Chanthaburi, Thailand in 1978. They were tested by the N and HI tests and a newly developed staining test against all four serotypes of dengue (DEN) virus and Japanese encephalitis (JE) virus. Four patients were demonstrated to be cases of primary DEN infection and the other 16 to be cases of secondary DEN infection.