China barre la malaria de su territorio. ¿Cómo lo consiguió?

China Cleared its Territory of Malaria. How?

05.7.2021
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Since the 1950s, China has been implementing ground-breaking strategies against what was then the country’s most common infectious disease. Seventy years later, the WHO has certified China as “malaria-free”.

For several decades, China was the great unknown for Western malaria experts. Closed off from the world in the 1960s and on the outside of the World Health Organisation (WHO) for more than 20 years, China had technical contacts only with like-minded countries such as Russia until well into the 1980s. It was only relatively recently that Western malariology discovered—with admiration—the strategies that China put in place during the second half of the 20th century, which led to the country being certified, this week, as “malaria-free” by the WHO. “From 30 million cases to zero,” announced the WHO. The numbers are indeed impressive. But how did China do it?

"From 30 million cases to zero", announced the WHO. The numbers are indeed impressive. But how did China do it?

Despite being a founding member, China withdrew from the WHO in 1949, arguing that the organisation was dominated by capitalist ideology and would never succeed if it continued to deny the links between social and economic problems and health. In practice, this meant that China never participated in the Global Malaria Eradication Programme (1955-1969) and that, while most of the world was following the strategy of mass spraying of DDT against mosquitoes, China embarked on its own fruitful and highly original path.

At a time when malaria was the country’s most common infectious disease, endemic in 80% of its territory and with infection rates exceeding 40% in certain areas, in 1951 China launched its first National Malaria Control Plan. One of the key elements of this ambitious plan was the creation of “malaria stations”, which combined prevention and treatment with epidemiological investigation. Strongly influenced by the tradition of “barefoot doctors” and the importance of community involvement in health issues, by the late 1950s China had approximately one community malaria worker for every five households across its vast territory.

By the late 1950s China had approximately one community malaria worker for every five households across its vast territory

The information generated by this network of malaria workers made it possible to adapt strategies to different epidemiological conditions and to combine different tools according to the species of parasite, the intensity of transmission and the species of mosquito, among many other factors that influence the spread of malaria. In addition to spraying DDT, the Chinese introduced environmental interventions and larvicides. Crucially, mass campaigns were organised to administer antimalarial drugs to large population groups as a means of reducing transmission, including the use of primaquine to attack Plasmodium vivax during the dormant stages of its life cycle.

The malaria situation in China worsened dramatically in the 1960s and 1970s. The Cultural Revolution dismantled the health system in rural areas, while poverty, famine, forced displacement and major infrastructure works paved the way for the terrible epidemics that ravaged China in those years.

Paradoxically, the Cultural Revolution also gave rise to what is considered China’s greatest contribution to the fight against malaria today: the discovery of artemisinin, which would become the first-line treatment against the disease after malaria parasites developed widespread resistance to chloroquine.

The Cultural Revolution gave rise to what is considered China’s greatest contribution to the fight against malaria today: the discovery of artemisinin

At the height of the Vietnam War, when malaria deaths in the armies of North and South Vietnam were on a par with combat casualties, the Chinese government received a formal request from its North Vietnamese allies to develop a new antimalarial drug. Hundreds of scientists were coordinated under the auspices of Project 523, which was carried out under strict military secrecy. Given the climate of persecution against scientists and intellectuals, the researchers involved in the project lived in fear of reprisals from communist militias, going so far as to work at night under very difficult conditions to avoid arousing suspicion. Eventually they hit the jackpot, thanks to the confluence of “modern” pharmacology and traditional Chinese medicine. After systematically re-reading ancient Chinese Materia Medica and replicating age-old methods of extraction so as not to damage the active substances, the researchers first tested artemisinin (qinghaosu) on humans in 1972, with spectacular results. (Years later, the Chinese pharmacologist Tu Youyou would receive the Nobel Prize in Medicine for these efforts.)

Also in the 1970s, in Guangdong province, the first efficacy studies were conducted on what is now the most common—and most useful—malaria-prevention tool: insecticide-treated mosquito nets. As early as 1984—when the effectiveness of these nets was controversial in the rest of the world and the WHO had yet to recommend them—more than 5 million Chinese were already sleeping under their protection every night, leading to dramatic reductions in infection rates.

When the effectiveness of insecticide-treated mosquito nets was controversial in the rest of the world and the WHO had yet to recommend them, more than 5 million Chinese were already sleeping under their protection every night, leading to dramatic reductions in infection rates

The most recent stage in China’s long struggle against malaria began in the 1980s, when the government reinstated the free distribution of malaria drugs and diagnostics and strengthened the epidemiological surveillance system.

In 2010, under an umbrella of strong political support, China launched its malaria elimination plan, which was based on the “1-3-7” strategy: health facilities have one day to report a malaria diagnosis; the case must be confirmed and investigated within three days; and a public health response to prevent further transmission must be undertaken within seven days. Hearkening back to the origins of Chinese malariology, the 1-3-7 strategy was implemented by primary care centres and complemented by specific strategies in particularly conflictive areas, such as borders with higher-transmission countries.

Seventy years after the establishment of its first malaria plan, and after countless ups and downs, the WHO announcement confirms that there have been no locally transmitted cases in China for the past three years and that the country has a system in place to detect imported cases and prevent the spread of infection. From 30 million cases to zero, says the WHO. And to that we respond: Cheers!