CAMBODIA, 1st EPIDEMIOLOGICAL SURVEY

May 2018

Saliva test: dengue laboratory diagnosis is essentially based on detection of the virus or antibodies directed against the virus in blood samples. Blood, however, may be difficult to draw in some patients, especially in children, and sampling during outbreak investigations or epidemiological studies require many specimens. Anne Claire Andries (IPC) established that a slight decrease in the diagnostic performances when using serological tests in saliva samples instead of blood is balanced by the number of individuals that can be investigated during studies when non-invasive sample collection methods are used. This test offer a useful benefit for biological diagnosis in field conditions.
More than 3,000 children have been sampled from May 23rd to May 26th in 5 districts in Kampong Cham and Tboung Khmum province.
A team of 48 people including the team of the Epi-Unit at IPC, local monitors and teachers have been mobilized to collect the samples in 24 schools. The integrated vector control is implemented in 12 schools and 12 non-intervention schools serve as control.
Samples were shipped every day to the Virology Unit of IPC where ELISA indirect test (IgG arboviruses) and MAC ELISA test (IgM arboviruses) will be performed.
This testing campaign that aims at determining the immune status of children before the dengue season will be followed by 2 operations in July in October 2018 to assess variation of sero-conversion in these 3000 children during the rainy season.
In parallel the active surveillance is conducted in 70 villages and involving more than 78,000 children from 5 to 15 years old; children identified by Village Health Volunteers with dengue like syndrome are blood sampled; children positive by PCR testing (dengue virus is detected in the blood) will be tested few days later by saliva test to regularly validate sensitivity of the test.