It is often not appreciated that parasites of humans (parasitic protozoa and parasitic helminths) represent our most common and even ubiquitous pathogens. Parasites are important causes of human pathology and disease that rival our great killer infections, such as tuberculosis, HIV/AIDS, diarrheal diseases, and lower respiratory infections. Shown in Table 46-1 is the most recent assessment of the global public health impact of human parasitic diseases, as determined by the Global Burden of Disease Study 2016 (GBD 2016 Causes of Death Collaborators, 2017; GBD 2016 Disease and Injury Incidence and Prevalence Collaborators, 2017).
TABLE 46-1Ranking of Human Parasitic Diseases Either by Deaths or Numbers of Prevalent or Incident Cases, Based on the Global Burden of Disease Study 2016 ||Download (.pdf) TABLE 46-1 Ranking of Human Parasitic Diseases Either by Deaths or Numbers of Prevalent or Incident Cases, Based on the Global Burden of Disease Study 2016
|Rank ||Disease ||Numbers of Deaths (GBD 2016 Causes of Death Collaborators, 2017) |
|1 ||Malaria ||719,600 |
|2 ||Visceral leishmaniasis ||13,700 |
|3 ||Schistosomiasis ||10,100 |
|4 ||Chagas disease ||7,100 |
|5 ||Ascariasis ||4,900 |
| ||Total for the five leading causes ||755,400 |
|Rank ||Disease ||Numbers of Prevalent or Incident Cases (GBD 2016 Disease and Injury Incidence and Prevalence Collaborators, 2017) and DALYs (disability-adjusted life years measures overall disease burden, expressed as the number of years lost due to ill-health, disability or early death) (GBD 2016 DALYs and HALE Collaborators, 2017) |
|1 ||Ascariasis ||800 million prevalent cases (1.3 million DALYs) |
|2 ||Hookworm ||451 million prevalent cases (1.7 million DALYs) |
|3 ||Trichuriasis ||435 million prevalent cases (0.3 million DALYs) |
|4 ||Malaria ||213 million incident cases (56.2 million DALYs) |
|5 ||Schistosomiasis ||190 million prevalent cases (1.9 million DALYs) |
| ||Total for the five leading causes ||>2 billion prevalent or incident cases (61.4 million DALYs) |
Together, the five leading causes of parasitic deaths resulted in over 750,000 deaths in 2016, with most of those deaths caused by malaria (GBD 2016 Causes of Death Collaborators, 2017). To put that number in perspective, the only specific infectious diseases that outrank malaria or parasitic diseases overall are tuberculosis (1.213 million deaths) and HIV/AIDS (1.033 million deaths) (GBD 2016 Causes of Death Collaborators, 2017). However, even these estimates for parasitic infections may not fully consider all of the deaths, given that many of the deaths from kidney and liver disease resulting from schistosomiasis, or anemia from hookworm, are frequently attributed to other causes, and there are suggestions that the numbers of people dying from sudden death or heart failure from Chagas disease annually may be much higher than previously realized (Herricks et al, 2017).
Another striking feature of parasitic diseases is the observation that they occur universally among people who live in poverty. The entire population of the world’s poor is affected either by malaria or by helminth infections, led by the three soil-transmitted helminth infections and schistosomiasis (GBD 2016 Disease ...