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Table 1 Epidemiologic aspects, route for transmission, and methods used for the definitive diagnosis of the parasitic diseases

From: Parasitic diseases as a cause of acute abdominal pain: imaging findings

Disease Parasite Epidemiology Geographic distribution 1 Hosts/vectors
2 Transmission
Final diagnosis (routinely used method)
Cystic echinococcosis(c) [3,4,5,6] E. granulosus(a) 2–404/10,000 High prevalence in Mediterranean regions, southern and central parts of Russia, central Asia, China, Australia, South America and Africa 1 Definitive hosts (dogs and foxes)
Intermediate hosts (sheep and human)
2 Ingestion of eggs
- Imaging based (primarily ultrasound findings)
- Serologic assay
- Aspiration of cyst content during imaging guided intervention
E. multilocularis 0.2–3400/100,000 Asia, Central Europe and the northern parts of Europe, and North America
E. oligarthrus Very rare, 106 human cases Central and South America
E. vogeli
Fascioliasis(c) [3, 7] F. hepatica(a) 0.9–6.1% Worldwide, high prevalence in Europe and America 1 Intermediate hosts (Freshwater snails)
Definitive hosts (herbivorous mammals, including humans)
2 Ingestion of watercress or contaminated water containing encysted larva
- Stool examination
- Serologic assay
F. gigantica Tropical areas of Asia and Africa
Ascariasis(c) [3, 8] Ascaris lumbricoides 8.8–22.3% Asia, Africa, and South America 1 No intermediate host
Humans are the only definitive hosts
2 Ingestion of fecally contaminated food
Stool examination
Toxocariasis(c) [9] T. canis(a) 0.7–15% Worldwide 1 Intermediate hosts (rabbit, lamb, fowl)
Definitive hosts (domestic dogs and cats). Humans are accidentally infected intermediate hosts
2 Ingestion of eggs from contaminated foods
Serologic assay
T. cati
Intestinal taeniasis(c) [10,11,12] T. saginata 0.7–4.9% Sub-Saharan Africa and the Middle East, Eastern Europe, the Philippines, and Latin America 1 Intermediate hosts (pigs for T. solium, cattle for T. saginata)
Definitive hosts (Humans are the only definitive hosts)
2 Ingestion of larvae for taeniasis and ingestion of eggs for cysticercosis
Stool examination
T. solium Worldwide; especially in Mexico, Latin America, West Africa, Russia, India, Manchuria, and Southeast Asia
T. asiatica Taiwan, Korea, Indonesia, Nepal, Thailand and China
Amoebiasis(c) [13] E. histolytica(b) 5–42% Worldwide. Endemic in developing parts of Central and South America, Africa, and Asia 1 Humans are the principal host and reservoir
2 Ingestion of the cyst from fecally contaminated food or water
- Stool examination
- The real-time PCR (to identify E. histolytica)
E. dispar(a)
E. moshkovskii
Malaria(c) [14, 15] P. falciparum(b) 5.2–75% Tropical Africa, South America, South-eastern Asia, and Western Pacific 1 Vectors (Anopheles mosquitos)
2 Transmitted by infected female mosquitoes’ bites
Microscopic examination of blood
P. vivax
P. ovale
P. malariae
P. knowlesi
Visceral leishmaniasis(c) [16] Leishmania(a,b)donovani 200,000–400,000/per year Northeast of the Indian subcontinent, East Africa 1 Vectors (Phlebotomus sandflies)
2 Transmitted by infected Phlebotomus sandflies’ bites
- Bone marrow sampling
- Serological examination
Leishmania infantum Mediterranean region, Latin America
Dientamoebiasis(c) [17] Dientamoeba fragilis 0.4–42% Worldwide 1 Humans are the principal host
2 Fecal-oral (hypothetical transmission via Enterobius vermicularis eggs)
Stool examination
Anisakiasis(c) [18] Anisakis simple 3/1,000,000 in Japan Japan, Korea, Latin America, and Europe (Scandinavia, The Netherlands, Spain, France, Britain). Over 90% of cases are from Japan 1 Intermediate hosts (different species of crustaceans, fish, or squid)
Definitive hosts big sea mammals (whales, dolphins, or seals)
Humans are accidentally infected intermediate hosts
2 Ingestion of raw or undercooked fish containing larvae of the anisakis worm
Endoscopy, histopathological examination
  1. aMost common
  2. bMore severe clinical presentation
  3. cReferences