According to national and international health agencies, the United States has significantly higher rates of cancer, chronic illness, and metabolic disease than many other countries. Nations such as Brazil, India, Bangladesh, the Philippines, and Kenya report substantially lower rates of cancer and many chronic diseases than those seen in the United States. Many of these countries participate in national deworming programs supported by the World Health Organization (WHO) and UNICEF. These initiatives include school-based deworming, community mass-treatment campaigns, and routine parasite surveillance in regions where parasitic infections are endemic.
In these countries, parasite management is considered a routine component of public health. By contrast, the United States rarely screens for parasitic infections unless symptoms are severe, highly specific, or identifiable risk factors are present. These differences in public health practices present an observable contrast: many countries with routine parasite-control programs also report a lower burden of chronic illness and cancer than the United States. While these comparisons do not identify a single cause, they raise important questions about how differing public health strategies may influence long-term population health alongside numerous other contributing factors.
As the available public health data are examined more closely, these patterns become increasingly noticeable. In many countries that maintain routine deworming programs, diabetes prevalence often ranges between 2 and 5 percent of the population, while the United States reports a prevalence exceeding 11 percent. Similar differences are observed across other chronic conditions, including cardiovascular disease, asthma, and autoimmune disorders, for which the United States consistently reports comparatively high rates.
These contrasts do not point to a single explanation. Rather, they illustrate how populations experience long-term disease differently under varying environmental conditions, healthcare systems, public health priorities, and lifestyle factors.
Cancer incidence follows a similar pattern. In the United States, approximately 367 people per 100,000 are diagnosed with cancer each year. With a population of roughly 340 million, that equates to approximately 1.25 million new cancer cases annually. By comparison, the Philippines reports a cancer incidence of approximately 185 cases per 100,000 people. With a population of about 117 million, that corresponds to roughly 216,000 new cancer cases each year.
Countries including India, Bangladesh, Kenya, Uganda, Tanzania, and Nepal—all of which participate in WHO-supported deworming programs—also report lower overall cancer incidence and lower rates of several chronic diseases than the United States. Although every nation differs in demographics, genetics, lifestyle, healthcare access, environmental exposures, and methods of disease reporting, the overall observation remains consistent: many countries that maintain routine parasite-control programs also report lower rates of chronic illness and cancer than the United States.
This association does not establish causation, but it represents a pattern that may warrant further scientific investigation.
This leads to another observation researchers have made regarding how infections behave within different biological environments. Some studies suggest that parasites can respond to changes in the host environment, including changes influenced by certain pharmaceuticals. This does not mean medications cause or eliminate parasitic infections. Rather, some medications may alter biological pathways on which parasites depend.
Many parasites rely on host processes such as inflammation, neurotransmitter activity, hormone signaling, and metabolic pathways to move, feed, reproduce, or interact with their host. When medications modify these systems for therapeutic purposes, experimental research has shown that some parasites may become less active, slow their movement, or alter their biological behavior. In the scientific literature, these responses are described as changes in motility, signaling, metabolism, or host-parasite interactions.
Researchers have suggested that these biological changes could influence how some parasitic infections present clinically, although this remains an area of ongoing scientific investigation. The Centers for Disease Control and Prevention (CDC) reports that parasitic diseases in the United States are often unrecognized, misdiagnosed, or undetected. The agency also notes that the nonspecific symptoms associated with many parasitic infections, combined with limited routine screening, may contribute to delayed or missed diagnoses.