A total of 37 passengers who arrived from Brazil have been screened for the disease between Aug 12 and Aug 21, with most of them arriving at KLIA and one in Penang.

Four of them were quarantined before being allowed entry into the country.

Health Director-General Noor Hisham Abdullah said the four did not have yellow fever vaccination but they were in healthy condition.

“The virus can be brought into Malaysia through visitors originating from countries which carry a risk of yellow fever transmission and have not been vaccinated for the disease,” he told NST Online.

The news report said three sports officials in the Malaysian Rio Olympic contingent, from Penang, were quarantined due to a yellow fever scare.

Those without a yellow fever vaccination certificate can be quarantined for up to six days upon arrival in Malaysia.

Yellow fever can be transmitted through the bite of the Aedes aegypti mosquito although the tiger mosquito (Aedes albopictus) can also serve as a vector for the virus.