Molecular Monitoring of Knockdown Resistance in Head Louse (Phthiraptera: Pediculidae) Populations in Iran.

Knockdown resistance (kdr) is a common mechanism of insecticide resistance in head lice to the conventionally used pyrethroid pediculosis and can be the result of various amino acid substitutions within the voltage-sensitive sodium channel (VSSC). In this study, 54 sequences from varied specimens were investigated to monitor well-known resistance mutations and probable new mutations. The Pediculus humanus capitis de Geer specimens were collected from 13 provinces in Iran. The specimens were stored in 70% ethanol until DNA extraction and PCR amplification of ~900-bp fragment of VSSC. The sequences were analyzed using different bioinformatics software for the detection of well-known kdr substitutions and additional mutations potentially associated with kdr resistance in head lice. There were six new and an old (haplotype I) kdr haplotypes within the Iranian head louse population. K794E, F815I, and N818D amino acid substitutions were reported for the first time. The P813H mutation was the most prevalent amino acid substitution in eight provinces. Among 53 sequences, 26 (49%) were homozygous susceptible, and 27 (51%) were heterozygotes. Thus, 51% of the head lice collected in Iran harbored only the P813H allele. The exact test for the Hardy-Weinberg (H-W) equilibrium showed that genotype frequencies differed significantly from the expectation in East-Azerbaijan and Tehran provinces. Moreover, these populations had an inbreeding coefficient (Fis) <0, indicating the excess of heterozygotes. This observation suggests that the populations of head lice from Iran are currently under active selective pressure. For the rest of the populations, H-W equilibrium and the expectations were significantly in harmony. The results of the current study highlight molecular techniques in the accurate detection of resistance genotypes before their establishment within the head louse population. Accurate detection of resistant genotypes seems to be helpful in decision-making on lice control programs and resistance monitoring and management.

Animal Bite and Deficiencies in Rabies Post-Exposure Prophylaxis in Tehran, Iran.

BACKGROUND: Rabies post-exposure prophylaxis (PEP) is an effective measure if administered immediately. We evaluated the primary health care provided after animal bite and determined the deviations from rabies PEP protocol. METHODS: This 6-year population-based cross-sectional study was conducted in Tehran, the capital of Iran, from April 2006 to March 2012. The study population included people who referred to health centers of Tehran, seeking PEP. The data were extracted from rabies registry databases using a checklist of items according to the context of the health records. All statistical analyses were performed at a significance level of 0.05 using Stata software, version 11. RESULTS: Of 22,766 cases of animal bite, 84.5% were men, 31.9% were aged 21-30 years, and 66.3% lived in urban areas. Most cases were the result of a dog bite (81.7%), mostly at midday (29.9%), and more frequently in spring (27.9%) and summer (27.7). Legs (45.6%) and hands (43.4%) were the most common sites of animal bite. The PEP was associated with a variety of shortcomings as follows. A majority of cases who had indication of receiving a 5-dose vaccination schedule had received only three doses. Most of the cases with a wound in the head and neck and many of cases with deep wounds had not received immunoglobulin. A number of cases needed to receive one-mL dose of vaccine while they had received 0.5-mL doses. CONCLUSIONS: According to our results, rabies PEP is not well monitored and the preventive measures are associated with some insufficiencies and deviations from the national PEP protocol which must be taken into consideration by public health authorities to ensure that rabies surveillance is efficient.