Worms, diseases that affect billions of people worldwide, have had little progress in clinical studies. One of the reasons this happens is because they reach the poorest populations, not attracting investment from pharmaceutical companies. The warning is in a study published in the magazine Drug Discovery Today by researchers from the University of São Paulo (USP) and the University of Guarulhos, which has the support of the São Paulo Research Foundation (FAPESP ).
The work takes place in a context where the World Health Organization (WHO) launched, in 2021, an action plan to eradicate or control, by 2030, 20 diseases that affect one in five people in the world. world and kill about 500,000 a year. . Of the 20 diseases, the five that most affect the most people in absolute numbers are worms. One of the strategies adopted in the search for new drugs is pharmacological repositioning, by studying existing drugs for these neglected diseases.
“Among the multiple goals that have been placed on the WHO roadmap is the search for new drugs, because many of these diseases do not have a vaccine and a drug that is considered very effective. Although it has a relatively good efficacy, but not sufficient to control the disease, in particular because there is no 100% effective drug”, explains Josué de Moraes, who coordinates the Nucleus for Research in Neglected Diseases (NPDN) at the University de Guarulhos, one of the authors of the article.
Schitoxomosis
Moraes cites, as an example, the schistosomiasis case, which is considered the main verminosis in terms of morbidity and mortality. “Although ascariasis, which is roundworm, affects a larger portion, almost a billion people, schistosomiasis has a greater impact on health,” he explains. There is only one drug available for the disease, praziquantel. “Imagine having a drug for a population of over 200 million,” he compares. Moreover, the drug also does not affect the young form of the parasite, preventing treatment from starting at the beginning of the infection.
The researcher underlines, among the impacts of worms, the fact that they alter the intellectual development of children, contribute to a drop in the rate of schooling and can also cause the person to be absent from work. “I always say that these diseases not only prevail in conditions of poverty, but also represent a strong obstacle to the development of countries and, therefore, are decisive in maintaining inequalities”, he assesses.
Among the reasons that prevent the development of studies in the field of parasitology, Moraes cites four. “Verminoses are the most neglected among the neglected, mainly because it is a type of disease more associated with the question of poverty than the others”, he points out, as the first obstacle. He also emphasizes the fact that illness does not give rise to a sense of urgency. “They do not visibly demonstrate that there is a need for the population.” He recalls that in some regions, worms are even perceived as something common, everyday.
Another difficulty arises in the laboratories. “Worms are difficult to care for. It is much more difficult to keep a worm in the laboratory, unlike certain diseases caused by protozoa, such as malaria, leishmaniasis, Chagas disease, among others”, he illustrates. This ends up harming the biological knowledge of the worms. “When available you need to have the definitive host, usually we use a rodent and an intermediate host, in the case of schistosomiasis a snail.” Moraes also highlights the disgust that worms arouse in individuals.
The researcher insists on recalling that other public health measures, such as diagnosis, control of transmission vectors and universal basic sanitation, are essential to deal with these diseases. “We have around 30 million Brazilians who live without treated water. Almost half of the population has no access to sewers. So this reinforces this picture, which I would say regrettable, compared to verminoses, ”he assesses.