In Kenya, where chloroquine has been useless for a decade, researchers reported in 1194 that more than 25% of malaria cases in a recent study were resistant to the two more modern and expensive antimalarial drugs, mefloquine and doxycycline. Between 1982 and 1986, the death rate from malaria in the paediatric wards of the largest hospital in Zaire rose from 4.8% to 15.3%. The new drug mefloquine has been widely used in Thailand, but in some areas only half the cases now respond to the drug. On the Thailand-Cambodian border, 80% of malaria is mefloquine-resistant.
Resistance to another favoured drug combination, sulfadoxine/pyramethamine is still generally affordable and effective in Africa. Some countries, such as Malawi, have moved to it as the village-level replacement for chloroquine. Resistance to the combination, however, is widespread in Southeast Asia and the Amazon Basin, and is now appearing in parts of Africa.