HARARE, Zimbabwe — Zimbabwe has closed a school after 100 students tested positive for COVID-19, state media reports, as authorities warn of the risk of a new wave of infections in a country that has so far recorded few cases.

The John Tallach Secondary School in the country’s west has been turned into a quarantine center, the Herald newspaper quotes Oppah Muchinguri-Kashiri, chair of the country’s COVID-19 taskforce, as saying. She says 73 students are asymptomatic and 27 show mild symptoms. An undisclosed number of teachers also tested positive.

Authorities suspect that a pupil who recently traveled to neighboring South Africa infected the others, the paper reports. South Africa, with more than 750,000 recorded infections, has the highest confirmed COVID-19 cases in Africa.