China, which eliminated several parasitic diseases over the last two decades, now faces a resurgence thanks to parasites being carried back into the country by visitors from Africa and other Asian countries, and by its own returning citizens, says a new study.
In 2013, Chinese President Xi Jinping launched the Belt and Road Initiative to enhance trade, infrastructure and economic relations with Asian and African countries. However, this resulted in exposing Chinese citizens to parasitic diseases which had earlier been eradicated in China.
“We need the enormously successful China-India pharma machine to turn its attention to neglected disease product development.” Bin Zhan, National School of Tropical Medicine, Baylor College of Medicine.
Currently, an estimated three million Chinese work in Africa. A significant impact of this fact is the import of parasitic infections, including schistosomiasis, African trypanosomiasis, cutaneous leishmaniasis and falciparum malaria. On the other hand, more than 430,000 Africans live in the Guangdong province alone for academic studies and business. According to the study, published January in PLoS Neglected Tropical Diseases, there is a need to expand monitoring and surveillance among both groups.
Estimates published by China’s ministry of health show that by the early 1990s, China had high prevalence of parasitic and other tropical diseases with more than half billion people infected with ascariasis. Additionally, some 200 million people suffered from trichuriasis and hookworm infection.
Strong economic development, massive reductions in the numbers of Chinese living in extreme poverty, urbanisation, changes in agricultural practices, improved sanitation and extensive parasite control measures helped eradicate several of these diseases, say the authors of the study.
Bin Zhan, an author of the study and associate professor at the National School of Tropical Medicine, Baylor College of Medicine, Houston, emphasises that China is “perhaps the first country to eliminate lymphatic filariasis and has made great strides toward eliminating Asian schistosomiasis. China has reduced dramatically infections of soil-transmitted helminths and has almost eliminated domestic malaria”.
“We were curious to explore how that track record might be exported,” says Zhan, noting that China is aggressively pursuing activities in Africa and Central Asia through the Belt and Road Initiative.
Zhan says that work is on, along with colleagues in China, for epidemiological studies that may lead to vaccine development against parasitic diseases. “We have seen the big change and great achievement of disease control for neglected tropical diseases in China and we think the experience may benefit other countries.”
Zhan says that China, as well as India, despite hosting large pharmaceutical industries, have been “somewhat underachievers in terms of developing new neglected diseases technologies drugs, diagnostics, and vaccines. We need the enormously successful China India pharma machine to turn its attention to neglected disease product development”.
Strong economic development has been important in the eradication of these diseases. Zahn believes, as well, that two other factors helped achieve this: the well-established infrastructure of health care and disease control and prevention in China, plus government investment in deworming and control of vectors that transmit diseases.
Xiao-Nong Zhou, director, National Institute of Parasitic Diseases and National Centre for Tropical Diseases Research, Beijing, says the report presents an accurate appraisal of neglected tropical diseases (NTDs) in China. “The achievements include the elimination of lymphatic filariasis in 2007. Moreover, no indigenous malaria case has been reported since 2017 and malaria is expected to be eliminated in China by 2020,” Xiao-Nong says.
“The prevalence of soil-transmitted helminthiasis has been reduced from more than 50 per cent in 1990 to less than five per cent in 2017, according to nationwide epidemiological surveys conducted by National Health Commission of China,” says Xiao-Nong.
“We need to focus on two areas. One is to continue our control or elimination programmes on NTDs in China, and the other is to transfer our Chinese working experience in NTDs control and elimination into other settings in Africa or Asia,” he says.