Poor Response to Albendazole in Hookworm-Infected Abnormal Haemoglobin Carriers

In southern Thailand, the low efficacy of albendazole contributes to the unsuccessful elimination of hookworms. Individuals infected with hookworms exhibiting low albendazole efficacy show decreased mean corpuscular volume and mean corpuscular haemoglobin and are suspected carriers of abnormal haemoglobin. This observational study aimed to compare the treatment outcomes of albendazole for hookworm infection in individuals with normal versus abnormal haemoglobin types.

227 stool samples were examined using the Kato-Katz and agar plate culture methods. Blood samples were collected from participants with hookworm-positive stool after oral administration of 400 mg albendazole to perform complete blood counts and haemoglobin typing. Treatment outcomes were evaluated 3 weeks after albendazole administration. Participants with persistent hookworm infection received a second 400 mg dose of albendazole, and outcomes were reassessed 3 weeks later.

Among 54 hookworm-positive participants, 38 were cured after the first round of treatment, and 5 were cured after the second round, all of whom had normal haemoglobin. However, 11 participants remained uncured after two treatment rounds, all with abnormal haemoglobin types: 7 with heterozygous haemoglobin E, 3 with heterozygous haemoglobin constant spring (CS) and 1 with compound heterozygous haemoglobin E/CS.

These findings suggest that abnormal haemoglobin may be a host factor contributing to low albendazole efficacy in treating hookworm infections.