Trichinella infection in a hunting population of Papua New Guinea suggests an ancient relationship between Trichinella and human beings

A new Trichinella species, Trichinella papuae, was discovered in 11.5% of wild pigs in a remote region of Papua New Guinea. A survey was conducted to determine whether the inhabitants of this region are infected with Trichinella, as wild-pig meat represents their main source of protein. The prevalence of anti-Trichinella antibodies and its determinants were assessed among the inhabitants in 51 of the villages in the Morehead District of Papua New Guinea. We tested and interviewed 1536 people (28.8% of the adult population). Anti-Trichinella IgG were detected in 10.0% (95% Cl 8.5-11.6%) of them. The prevalence of seropositivity was higher in males (12.7%) than in females (7.5%) (P < 0.01), and the seroprevalence significantly increased with age. In one area, seroprevalence was highest in villages nearest the hunting area in which wild pigs are infected with Trichinella papuae (P < 0.01). Seropositivity was also correlated with the consumption of raw or undercooked meat. Persons reporting pain in the muscle joints and limbs were more likely to be seropositive; no severe clinical manifestations were observed. That infection was never severe suggests that the seropositive people are reinfected relatively often, but with very few larvae. If the epidemiological pattern of Trichinella infection observed among the hunting population of this area is any indication of the pattern of infection in prehistoric hunters, we can speculate that Trichinella infection due to the consumption of meat from wild animals was possibly a common disease among prehistoric populations.