by Matthew Law

Palaeoparasitology is the study of ancient parasites, usually parasites of man. Parasites are useful to study because they can tell us about human disease in the past, and can also be an indicator of past human migration. The term 'parasite' refers to an organism that lives within another organism of a distinct species, called a host. The parasite gains nutrition and protection by living in or on the host organism. Hosts fall into a number of categories:

Parasites themselves fall into two groups:

(Reinhard 1992: 233) 

In archaeology, information about parasites in the past is usually retrieved from faecal remains or directly from human remains (Gonçalves et al 2002: 1). . Parasite remains have been used to address an extremely broad range of questions regarding past human behaviour and environment. Parasitology can show some interesting epidemiological patterns, with differences in parasitism revealed between ancient hunter-gatherers and agriculturalist populations, related to differences in sanitation, type of dwelling and diet (Gonçalves et al 2002: 2). Hunter-gatherers are found to be less infected by helminths, whereas in the United States it was found that agricultural groups showed comparatively higher prevalence in intestinal parasites (Araújo & Ferreira 2000: 89).

According to Darwin, species have only one geographical origin (Gonçalves et al (2002: 2)) . Therefore, it is possible to use parasites as biological markers to analyse ancient human migration, for example whether there was pre-Columban European contact with the Americas.  The parasite group ancyclostymids have been found archaeologically in both the New and Old Worlds. Gonçalves et al (2002: 4) report that the majority of finds are from the Americas and that human infection was present far before Columbus, with the oldest finding 7230 ± 80 years BP. This points to trans-oceanic contact before that date as ancyclostymids require warm, moist conditions outside of their hosts to complete their life cycles, and so could not have survived human migration by land through Beringia during the last ice age (Gonçalves et al 2002: 4). Gonçalves et al (2002: 4) argue that coastal navigation along the south coast of Beringia is a more likely route. Transpacific contact from southern Japan to coastal Ecuador has also been put forward as a possible route (Reinhard 1992: 241).

In archaeology, only the most durable parasite remains are likely to be found. These include the eggs and sometimes larvae of helminths, which include tapeworms (cestodes), flukes (trematodes), thorny-headed worms (acanthocephalans) and roundworms (nematodes). Rarely, adult nematodes are found in mummies (Reinhard 1992: 233).

REFERENCES

Araújo, A., and L.F.Ferreira, 2000. Palaeoparasitology and the Antiquity of Human Host-Parasite Relationships. Mem Inst Oswalso Cruz, Vol 95 Suppl. 1: 89-93

Gonçalves, M.L.C., A. Araújo, L.F. Ferreira, 2002. Human Intestinal Parasites in the Past: New Findings and a Review. Mem Inst Oswaldo Cruz, Vol 97, 1-16.

Reinhard, K, 1992. Parasitology as an interpretative tool in archaeology. American Antiquity 57 (2), 231-245

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