EXPANSION OF THE KNOCKDOWN RESISTANCE HUMAN HEAD LICE (PHTHIRAPTERA: PEDICULIDAE) FROM ORPHANAGES IN SOUTH SUMATERA (INDONESIA)
The head louse Pediculosis capitis affects all races and social levels, particularly those of low socioeconomic status. Currently, the mainstay treatment for pediculosis is insecticides such as permethrin but the extended use of permethrin worldwide has led to growing pediculicide resistance. There fore, this study investigated knockdown resistance (kdr) mutations in head lice populations from orphanages in three different localities in the Palembang (Indonesia). Forty-eight head louse samples were collected from twelve orphanages in the Palembang Subdistrict and subjected to PCR to amplify the α subunit of the voltage-sensitive sodium channel (VSSC) gene, kdr mutation (C! T substitution). Restriction fragment length polymorphism (RFLP) patterns and sequencing were used to identify the kdr T917I mutation and demonstrated three genotypic forms including homozygous susceptible (SS), heterozygous genotype (RS), and homozygous resistant (RR). Of 48 samples, 32 (66,6%) were SS, 8 (16,7%) were RS, and 8 (16,7%) were RR and the overall frequency of the kdr T917I mutation was 0.31. The nucleotide and amino acid sequences of RS and RR also showed T917I and L920F point mutations. In conclusion, this is the first study detecting permethrin resistance among human head lice from orphanages in the Palembang Subdistrict of South Sumatra, Indonesia by PCR-RFLP. The study data may increase awareness of the increasing occurrence of the kdr mutation in head louse in orphanages in the Palembang Subdistrict within the province of South Sumatra, Indonesia.