A resistência à cloroquina e a busca de antimalariais entre as décadas de 1960 e 1980 / Chloroquine resistance and the search for antimalarial drugs from the 1960s to 1980s

Em 1961, a Organização Mundial de Saúde (OMS) reconheceu a resistência de cepas de Plasmodium à cloroquina, o que estimulou programas de pesquisa e desenvolvimento de novas drogas sintéticas que pudessem substituí-la no combate à malária. Analiso o processo de pesquisa científica relativo à produção de antimalariais nos contextos nacional e internacional, em especial nos EUA e na China, entre as décadas de 1960 e 1980. Pontos de convergência e distanciamento são marcados pelas dinâmicas próprias de cada país e pelos interesses envolvidos nas relações internacionais, em relação aos quais fica evidente o papel central da OMS.

Localized permanent epidemics: the genesis of chloroquine resistance in Plasmodium falciparum.

Localized permanent epidemics occur when, for an indefinite period of time, there is a temporary but continuous introduction of unprotected non-immunes into the same locality of a hyperendemic area. The main epidemiological factors involved in the genesis of localized permanent epidemics were encountered in Pailin (Cambodia) the epicenter of drug resistance in Southeast Asia: a very efficient vector, Anopheles dirus, exophilic and of limited distribution with, therefore, adjacent hyperendemic and non-endemic areas; a permanent pole of attraction in the hyperendemic area: Pailin's sapphires and rubies; a temporary but continuous influx of non-immunes into the pole of attraction: continuous influx of non-immunes into the Pailin gem mining area. In the gem-mining Pailin village drug pressure was considerable: mass drug administration, a medicated salt project and permanent self-medication with very high doses, much higher doses being required to cure non-immunes with heavy infections and severe clinical attacks in epidemic situations. It appears, therefore, that the emergence of chloroquine resistance in Southeast Asia was the consequence of the localized permanent epidemics in Païlin. High level resistance was the result of continuous and intensive serial passages of P. falciparum in the non-immune subjects, large numbers of parasites being exposed to a high level of drug pressure at each passage. Similar epidemiological conditions are encountered in some parts of South America where the exophilic vector is An. nuneztovari. In Colombia, whose eastern mountains bordering Venezuela yield the most highly prized emeralds in the world, chloroquine resistance was detected at about the same time as in Southeast Asia.(ABSTRACT TRUNCATED AT 250 WORDS)