A South African variant of COVID-19 was detected for the first time in Mexico this week — including one case in neighboring Sonora.

So far, Mexican officials say only three cases of the South African variant of the coronavirus have been reported in the country — all on the same day this week.

Mexico’s head epidemiologist José Luis Alomía said two cases were detected in Campeche, in southern Mexico. The third was detected in Sonora, though the patient lives in neighboring Baja California. All three were isolated to prevent the spread.

The South Africa, UK and Brazil coronavirus strains are all circulating in Mexico now, Alomía said, but that none of them are dominant so far.