Officials from Pakkret municipality in Nonthaburi spray chemicals to kill mosquitoes in the area yesterday after receiving reports that local people had come down with dengue fever.
A team of experts led by the Disease Control Department's Dr Prasert Thongcharoen will confirm on Friday whether or not two babies were born with unusually small heads as a result of Zika virus infection, Public Health Ministry permanent secretary Dr Sop
Sopon said that out of the four pregnant women monitored for Zika, three had given birth to babies with unusually small heads, while the head of a foetus in a 37-week-pregnant woman was just 31cm.
Department of Medical Sciences chief Dr Apichai Mongkol said that initial blood tests on four mother-infant pairs had found no trace of the Zika virus.
The department conducted two antibody tests to determine if the mothers had any previous Flavivirus infection of Zika, dengue fever or meningitis.
Apichai said the immunoglobulin M (IgM) test didn't find any antibody, said to linger for up to one and a half months after infection, but the immunoglobulin G (IgG) test – to find antibodies that linger after infection for five months or longer – produced positive results for two mothers.
Doctors will test if the infection was from Zika, dengue, or meningitis before confirming the results on Friday.