As I mentioned above, malaria was a serious public health problem until its complete eradication in the third quarter of the 20th century. It mainly affected populations in the rice fields of the Mondego, Tagus and Sado river basins, as they were more exposed to mosquito bites. In these regions, malaria (also known as sezões) had long persisted as an endemic disease. In other words, the presence of the disease was constant throughout the year.
In 1939, the Malariology Institute was opened in Águas de Moura, with the support of the Rockefeller Foundation (United States of America). In this context, anti-sezonatic posts were built in rice farming areas (namely in the Sado Valley). At the time (1940s), around 70 thousand new cases of malaria were registered per year. All children (100%) living in these areas had an enlarged spleen (as a result of the disease). Very worrying panorama. It was urgent to organize the fight.
To this end, Francisco Cambournac applied all possible means of struggle at the time, both to combat the mosquito and to treat all patients.
All prevention and control measures were designed, developed, managed and, later, evaluated by him. His strategic idea aimed to end the transmission of parasites (plasmodia), with the dual perspective of reducing the risk of bites and treating all patients. Cambournac knew the epidemiological situation that he had previously investigated, both in terms of the vectors and the parasites that caused the disease. He introduced fish into the rice field canals that fed on mosquito larvae (fish of the genus Gambusia) and promoted the use of mosquito nets. All people with signs of having acquired the disease agent were treated with quinine.
This is how, in 1958, endemic malaria was eliminated in Portugal. A success. The mosquitoes remained, but malaria transmission ended because the “Portuguese” plasmodia ceased to exist.
With so many people arriving in our country with blood parasites acquired, for example, in Africa, what is the risk of malaria returning?
Answer: almost zero because the species of mosquitoes in Portugal, previously responsible for the transmission of malaria, despite continuing to exist, are not adapted to tropical plasmodia. That is, “Portuguese” mosquitoes transmitted the plasmodia that circulated here, but now they do not have the same capacity to transmit parasites imported from tropical areas.
(Continues)
Former Director General of Health
franciscogeorge@icloud.com