doctor richard mihigo of the world health organization: >> at w.h.o we are taking this quite very seriouslyecause, from some preliminary data that are starting to emerge, it's clearly showing that the new variant is the force behind the new wave that we are seeing in many countries. >> reporter: the spread of the new variant has prompted a raft of countries, including the u.s. to ban travel from south africa. the u.k. has gone a step further, banning new arrivals from the democratic republic of congo and tanzania, amid fears the mutant strain is spreading rapidly there. at least 20 other countries, including the u.s., have also found cases. and while travel bans shutting south africans o may help, borders remain open across africa. that leaves not just countries like the d.r.c., but others that are nations still open to flights from the rest of africa, vulnerable. and according to health officials like dr.alubi mulamba, the d.r.c. has seen a spike in infections over the last five months. >> the second wave of covid when it came, we have received many patients. when we can try to compare the