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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