Endemic endoparasites

Trichomonas vaginalis has not yet been a subject of a systematic investigation in Iceland. However, it is sometimes seen in cervical samples screened at The Cancer Detection Center of The Icelandic Cancer Society. During 1986-1997 the incidence of T. vaginalis decreased more or less continuously from 1.2 to 0.25% in 22 369-29 129 samples annually screened (Margr├ęt Snorradottir, personal communication). Cryptosporidium parvum was first searched for and detected in human faeces in 1986 (Eydal et al. 1990). Until 1997 its prevalence in 5 945 faecal samples examined at Keldur was 0.8%. Most of the infected individuals were hospitalized children. Cryptosporidium parvum is a common zoonotic species in Iceland. In a survey carried out on single faecal samples during 1990-1992, 50% of 40 foals examined were infected, so were 49.2% of 65 calves, 19.1% of 115 lambs, 11.1% of nine kittens and 5.5% of 55 pigs (Skirnisson et al. 1993b).

Toxoplasma gondii was already reported in humans in the 1950s (Feldman and Miller 1956; Bjornsson 1958). Jonsdottir and Arnadottir (1988) reviewed five antibody prevalence studies carried out on 1084 humans during 1956-1987. The overall prevalence was 10.1%.

Table 4.1 Endemic (end), probably endemic (end?), zoonotic (zoon), eradicated (erad), and imported (imp) human endoparasites found in Iceland. Occurrence score is based on the number of cases which have been reported by faecal examinations at the Institute for Experimental Pathology at Keldur. 0: not reported during 1973-1999, 1: one or few cases reported during 1971-1999, 2: annually reported during 1973-1999

Endemic (score) Zoonotic Eradicated Importeda (score)


Entamoeba histolytica Entamoeba hartmanni Entamoeba coli Entamoeba polecki Endolimax nana Iodamoeba buetschlii Acanthamoeba spp. Dientamoeba fragilis Giardia lamblia Chilomastix mesnili Trichomonas vaginalis Balantidium coli Blastocystis hominis Cryptosporidium parvum Toxoplasma gondii Plasmodium spp. Leishmania spp. Pneumocystis carinii Encephalitozoon cuniculi Trematoda

Clonorchis sinensis and/or related species

Fasciolopsis buski and/or related species

Schistosoma spp.


Taenia saginata

Taenia solium

Hymenolepis nana

Dipylidium caninum

Echinococcus granulosus


Enterobius vermicularis Ascaris lumbricoides Ascaris suum Trichuris trichiura Trichostrongylus spp.

Necator americanus/ Ancylostoma duodenale

(O) (O) (O) endb (O) (O) endb (O) end? end? end? (2) (O) end endb (O) (O) end (2) end end endb

zoon zoon zoon zoon zoon zoon erad erad erad zoon imp (2) imp (2) imp (2)

Strongyloides stercoralis Toxocara cati Toxocara canis Pseudoterranova decipiens Anisakis simplex Wuchereria bancrofti Oncocerca volvulus









Notes a Infections of tourists and immigrants acquired abroad. b Not reported from Icelandic humans but a known zoonotic species.

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Furthermore, a T. gondii-induced abortion as well as ocular and congenital toxoplasmosis have been reported (Bjornsson 1958; Jonsdottir and Arnadottir 1988; Thorarensen et al. 1992). A recent survey showed that 30.2% of 149 domestic cats were seropositive (Finnsdottir 1997). Also, T. gondii oocysts have been detected in cat faeces collected in playground sandboxes (Smaradottir and Skirnisson 1996). Pneumocystis carinii is detected in one or two immunocompromised patients in Iceland every year. Records from the National University Hospital indicate that a stable incidence of P. carinii-caused pneumonia over the past 15 years (Ingibjorg Hilmarsdottir and Jonas Hallgrimsson, personal communications).

Enterobius vermicularis was first reported by Mohr (1786) but since 1881 its occurrence has been reported frequently (Health Reports 1881-1990; Matthiasson 1917, 1921; Sambon 1925; Hansen 1926; Kreis 1958). A recent survey on pinworm infections of 184 children in play schools in Iceland indicated that infections were rare in 2- and 3-year-old children but 13.2% of 4-year-old and 7.1% of 5-year-old children were infected ( Jonsson and Skirnisson 1998; Skirnisson 1998). Another survey among 186 children, 6- to 8-years-old, in four primary schools in the capital area revealed an overall infection prevalence of 14.5%. No pinworm infections were detected in two of the 12 schoolrooms included in the survey, but the highest prevalence found in a schoolroom was 38.5% (Skirnisson and Stefansdottir, unpublished data).

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