Zoonotic endoparasites

Several zoonotic protozoans and helminths, which have not (yet) been reported from humans (except probably for Ascaris suum, see subsequently), are known to be endemic in Iceland. Recently Entamoebapolecki, Iodamoeba buetschlii, and Balantidium coli were reported in domestic pigs (Eydal and Konradsson 1997). However, indigenous human infections have never been reported. The fourth protozoan, Encephalitozoon cuniculi, occasionally reported from humans abroad, has been confirmed in some wild mammals and in farmed foxes (Hersteinsson et al. 1993). Already in the nineteenth century Toxocara cati and Toxocara canis were reported from cats and dogs (Krabbe 1865). Recent surveys on endoparasites of cats (Agustsson and Richter 1993) and dogs (Richter and Elmarsdottir 1997) showed that both species are still common. Also, T. canis has been reported from the native arctic fox (Skirnisson et al. 1993a). However, human toxocariosis has not been reported in Iceland and none of 307 healthy blood donors, examined in 1981 for Toxocara antibodies, appeared to be seropositive (Woodruff and Savigny 1982). Infectious eggs of both species have been detected in playground sandboxes in Iceland (Smaradottir and Skirnisson 1996).

Pseudoterranova decipiens, Anisakis simplex, and other anisakine larvae are common in marine fish around Iceland. Potentially, they are capable of infecting humans but as traditional preparation of fish in Iceland does not include the consumption of raw fish the risk of getting infected is regarded to be minimal.

Ascaris suum is an endemic parasite of domestic pigs in Iceland (Richter 1991; Eydal and Konradsson 1997). As already mentioned the morphologically similar A. lumbricoides is not regarded to be endemic anymore. A case is known where an Ascaris infection was acquired on a pig farm. In general, however, human A. suum infections seem to be exceptional.

Three host-specific human ectoparasites are endemic in Iceland (Table 4.2). Sarcoptes scabiei, first reported by Petursson (1834), has probably been endemic since Iceland was settled. Since 1881 sarcoptidosis has been a notable disease. The number of annually registered cases has markedly changed. As an example, only eight cases were reported in 1961 but most cases in this period, 1569, were recorded in 1941. In the 1980s, on an average, 426 cases were annually registered (Health Reports 1881-1990).

Phthirus pubis has been endemic in Iceland for centuries, but its incidence has probably always remained low. First confirmed reports on its occurrence are from post-medieval archaeological excavations from Reykholt (Buckland et al. 1992). By the middle of the eighteenth century Olafsson (1981) reported a species with the name Pediculus ferus and mentioned that infestations were sometimes observed on foreigners. Petursson (1834) discussed methods to get rid of P. pubis, which he obviously regarded as a problem in Iceland in the late eighteenth century. Health Reports from the former half of the twentieth century occasionally report phthiriasis but Overgaard (1942) and Gigja (1944) state that P. pubis hardly occurs outside harbor areas in Iceland. According to Health Reports the number of phthiriasis cases increased during the Second World War. At present, dermatologists regularly confirm the presence of P. pubis (Jon Hjaltalin Olafsson, personal communication).

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