HEAD LOUSE PALEOEPIDEMIOLOGY IN THE OSMORE RIVER VALLEY, SOUTHERN PERU.

Recent studies of louse ectoparasites from mummies have developed robust data sets that allow a true epidemiological approach to the prehistory of louse parasitism. One epidemiological principle is that the binomial of overdispersion is normally negative, meaning that in a host population, parasites are aggregated in a few individuals. We demonstrate the overdispersion of lice in 3 different prehistoric communities that differ along 3 axes or variables: environmental setting, socioeconomic status, and cultural affiliation. Distinct cultural practices could have been involved in different patterns of louse infestation. Prevalence, intensity, and abundance of infestations exhibit statistically significant differences between the communities. We also find differences in prevalence between subadults and adults that contrasted by cultural affiliation and suggest conditions different from those seen today. We show that overall prevalence was affected primarily by ecological setting, not socioeconomic status nor cultural affiliation. These findings demonstrate that statistical analysis of archaeological data can reveal the states of infestation in past populations with lifestyles not seen in modern people. Our approach paves the way for future comparisons of subpopulations within archaeological communities.

Automontage microscopy and SEM: A combined approach for documenting ancient lice.

Human ectoparasites, including lice, have been recovered from a wide range of archaeological materials. The human head louse, Pediculus humanus capitis, has been identified from mummies and sediments for decades. Louse eggs are the body part most commonly encountered and therefore the most frequently quantified. Typically, several types of microscopy are applied for egg documentation. For studies in which quantification of infestation is a goal, counting is done with the naked eye or with the aid of handheld lenses. For determination and stage classification, stereomicroscopy is commonly used. For more detailed examination of microstructure, light microscopy, scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM) can be employed. In most reports, researchers use two or more techniques to accomplish interrelated goals. Automontage microscopy is used to document prehistoric arthropods with good success. Herein, we report the results of a combination of SEM and automontage microscopy to document lice and eggs recovered from South American mummies. This combined approach allows for simultaneous examination of internal and external characteristics. Thirty automontage composite images of 2 adult lice and 16 eggs showed that egg internal morphologies were easily examined showing the within-egg anatomy of emergent nymphs. SEM imaging of 9 lice and 129 eggs was completed. In the case of two adults and several eggs, SEM imaging was accomplish after automontage image capture of the same specimens. This one-to-one image comparison of SEM and automontage shows that transmitted light of automontage reveals egg internal structures and details of the adult lice. SEM allows for high magnification examination of egg, nymph and adult microstructures. We conclude that automontage imaging followed by SEM results in efficient graphic documentation of rare louse specimens.

Parasitism of the Zweeloo Woman: Dicrocoeliasis evidenced in a Roman period bog mummy.

We undertook the analysis of Zweeloo Woman, a bog mummy from the Netherlands, to assess her parasitic state. Evidence of infection came from two areas: (1) liver paraffin sections and (2) microfossils washed from an intestinal section. Although the liver had shrunken considerably, objects consistent with operculated trematode eggs were found. After evaluating the range of trematode species that produce eggs in liver tissue, we arrived at the diagnosis of Dicrocoelium dendriticum. Although only 0.1ml of sediment was recovered from an intestinal section, eggs of Ascaris lumbricoides and Trichuris trichiura were also identified. No eggs of D. dendriticum were revealed by the intestinal wash although they were observed in the liver. The lancet fluke, D. dendriticum, is a zoonosis that usually infects ruminants such as cattle. Eggs of D. dendriticum may be found in human coprolites if infected cow liver, for example, was eaten. This is false parasitism. Since eggs of D. dendriticum were found in the liver of Zweeloo Woman, we are assured this was a true infection. This find is especially significant because it is the oldest known, patent infection of D. dendriticum in humans.