"F. buski" is endemic in Asia including China, Taiwan, Southeast Asia, Indonesia, Malaysia, and India. It has an up to 60% prevalence in India and mainland China and has an estimated 10 million human infections. Infections occur most often in school-aged children or in impoverished areas with a lack of proper sanitation systems.

"F. buski" was endemic in central Thailand, affecting about 2,936 people due to infected aquatic plants called water caltrops and the snail hosts which were associated with them. The infection, or the eggs which hatch in the aquatic environment, were correlated with the water pollution in different districts of Thailand such as Ayuthaya Province. The high incidence of infection was prevalent in females and children ages 10–14 years of age.

Infection can be prevented by immersing vegetables in boiling water for a few seconds to kill the infective metacercariae, avoiding the use of untreated feces ("nightsoil") as a fertilizer, and maintenance of proper sanitation and good hygiene. Additionally, snail control should be attempted.

Trematodiases refers to a number of different trematode infections, many of which are spread by other animals. In 2015 the food born ones affected about 71 million people.

- Food-borne trematodiases as listed by the WHO:

- Clonorchiasis

- Opisthorchiasis

- Fascioliasis

- Paragonimiasis

- Others:

- Metagonimiasis

- Fasciolopsiasis

- Metorchiasis, caused by the Canadian liver fluke

- Dicrocoeliasis

Helminths are common causes of hypereosiophilia and eosinophilia in areas endemic to these parasites. Helminths infections causing increased blood eosinophil counts include: 1) nematodes, (i.e. "Angiostrongylus cantonensis" and Hookworm infections), ascariasis, strongyloidiasis trichinosis, visceral larva migrans, Gnathostomiasis, cysticercosis, and echinococcosis; 2) filarioidea, i.e. tropical pulmonary eosinophilia, loiasis, and onchocerciasis; and 3) flukes, i.e. shistosomiasis, fascioliasis, clonorchiasis, paragonimiasis, and fasciolopsiasis. Other infections associated with increased eosinophil blood counts include: protozoan infections, i.e. "Isospora belli" and "Dientamoeba fragilis") and sarcocystis); fungal infections (i.e. disseminated histoplasmosis, cryptococcosis especially in cases with [[central nervous system]] involvement), and coccidioides); and viral infections, i.e. Human T-lymphotropic virus 1 and HIV.

Hypereosiophilia or eosinophilia may be associated with the following autoimmune diseases: systemic lupus erythematosus eosinophilic fasciitis, eosinophilic granulomatosis with polyangiitis, dermatomyositis, severe rheumatoid arthritis, progressive systemic sclerosis, Sjogren syndrome, thromboangiitis obliterans, Behcet syndrome, IgG4-related disease, inflammatory bowel diseases, sarcoidosis, bullous pemphigoid, and dermatitis herpetiformis.