Parasite eggs in 16th-18th century cesspits from Granada (Spain)

The study of parasites from archaeological materials can yield information on socioeconomic conditions, as well as hygiene and waste management. The investigation of contemporaneous texts offers a complementary approach to understanding health in the past. Finding ancient parasites has proved important for analyzing structures related to waste management, such as latrines, cesspits and sewer drains. The aim of this study was to analyze the sediment in four cesspits from the early modern period (16th-18th century CE) in the city of Granada, Spain. After rehydration, homogenization, and micro-sieving (RHM) with subsequent visualization under optical microscopy, roundworm (Ascaris sp.) and whipworm (Trichuris sp.) eggs were detected in all four cesspits, with liver fluee (Fasciola sp.) eggs also being found in one cesspit. These findings are consistent with written sources from this period, which describe waste management challenges as a cause of water contamination and reveal the possible utilization of human fecal material as fertilizer. The spread of parasites would have been favored by overcrowding in the city. This study offers the first analysis of cesspits from the early modern period in the Iberian Peninsula, and demonstrates that ineffective sanitation led to widespread infection of the population by intestinal worms.