More than 100 gemstone traders from Africa have come down with Covid-19 over four days in Chanthaburi.

None had the African or Indian variants of the virus.

Some 109 traders tested positive May 6-9. They are from Guinea, Mali, Cote D'Ivoire and Gambia. Chanthaburi has attracted many traders of gems from Africa.

Medical workers set up a testing site for 250 residents who came into contact with the African traders.

Police warned the traders must go into quarantine for at least 14 days.

Meanwhile, two new clusters of Covid-19 infections have emerged in Chiang Mai where the virus was transmitted from family to friends, officials said.

The clusters were found in Doi Saket and Mae Wang districts as local authorities were ramping up their testing.

Officials said 26 new cases of Covid-19 were reported in Chiang Mai on Saturday.

The Doi Saket cluster broke out after an infected delivery worker returned home from Bangkok and failed to register with the health app on his arrival. Officials were unable to track him.

In the Mae Wang cluster, eight people contracted the virus. Parents became infected after visiting an entertainment venue in early April.