Background/aims: Human disease caused by the canine hookworm Ancylostoma caninum and a high incidence of eosinophilic enteritis have been reported from northern Queensland, Australia. The aim of this study was to evaluate patients with unexplained abdominal pain and a possible association with cryptic infections by A. caninum.
Methods: The clinical and demographic features of patients from this region with eosinophilic enteritis (group A1, n = 42), obscure abdominal pain associated with (group A2, n = 105) and without (group A3, n = 84) blood eosinophilia were reviewed and sera were tested against A. caninum excretory-secretory antigens by enzyme-linked immunosorbent assay (ELISA) and Western blot. Four additional patients, two with confirmed A. caninum, had hookworm infection.
Results: The level of dog ownership in these four groups was 79%-100%, higher than in the local population (P < 0.001). The ELISA tested positive in 71% of A1, 67% of A2, and 30% of A3, versus 8% in controls (P < 0.002). All cases tested were positive on Western blot versus 10% of controls (P < 0.0001). The ELISA values increased with chronicity and decreased during convalescence.
Conclusions: We conclude occult human A. caninum infections are common and are characterized by eosinophilic enteritis and obscure abdominal pain with or without blood eosinophilia. The diagnosis can be confirmed by serology.