Insecticide Susceptibility Status of Wild Population of Phlebotomus kandelakii and Phlebotomus perfiliewi transcaucasicus Collected from Visceral Leishmaniasis Endemic Foci in Northwestern Iran

Background:

Phlebotomus kandelakii and Phlebotomus perfiliewi transcaucasicus sand flies are the vectors of visceral leishmaniasis in Iran. The aim of this study was to evaluate the susceptibility of Ph. kandelakii and Ph. perfiliewi transcaucasicus, collected from an endemic focus of visceral leishmaniasis (VL) in the northwest of Iran, to different selected insecticides.

Methods:

Sand flies were collected from the villages of Meshkinshahr and Germi Counties using light traps and aspirators from May to October 2019. The sand flies were identified as Ph. kandelakii and Ph. perfiliewi transcaucasicus using standard identification keys. Susceptibility test was carried out against DDT (4%), Malathion (5%), Propoxur (0.1%) and Lambda-cyhalothrin (0.05%) according to the WHO standard method. MedCalc statistical software was employed to calculate LT₅₀ and LT₉₀ and to compare the chances of sand flies surviving the exposure to the studied insecticides.

Results:

A total of 1,278 female specimens were used for the susceptibility tests. Out of which 1,063 samples were used for the test and 215 for the control group. The estimated LT₅₀ values for DDT (4%), Malathion (5%), Propoxur (0.1%), and Lambda-cyhalothrin (0.05%) for Ph. kandelakii were 15.1, 13.4, 15.4 and 5.8 minutes respectively, and for Ph. perfiliewi transcaucasicus were 11.9, 15.6, 15.9 and 5.8 minutes respectively.

Conclusion:

This susceptibility studies revealed different LT₅₀ values for different insecticides efficient against Ph. kandelakii and Ph. perfiliewi transcaucasicus. The regular monitoring for the resistance of Ph. kandelakii and Ph. perfiliewi transcaucasicus sand flies seems necessary in diseases control programs in this area.

Epidemiology of Visceral Leishmaniasis with Emphasis on the Dynamic Activity of Sand Flies in an Important Endemic Focus of Disease in Northwestern Iran

Background

Leishmaniasis diseases are known to be one of the most important public health problems in World and Iran. Visceral leishmaniasis is considered to be the most serious form and transmitted by sand flies species. The aim of this study was to investigate the dynamic activities of sandflies in northwestern Iran.

Methods

This crass-sectional study was conducted from April to December 2018 in Meshkinshahr County, Ardabil Province. Sticky traps have been used to collect sand flies. They are stored in 70% alcohol and finally identified using valid keys. The aspects of the synoptic information were inquired from the Meshkin Shahr weather department and results analyzed for SPSS24.

Results

Totally 259 sandflies were collected during study period. From collected samples 78.7% were male and 21.3% female. There were 8 different species. Phlebotomus kandelakii was the most prevalent one (30.8%). The average temperature, relative humidity, and average wind speed was 13.5 °C, 84%, and 2 meters per hour on the onset of sandflies' activity, respectively. These values were 18.3 °C, 85% and 1.5 meters per hour at the peak of their activity and 16 °C, 62% and 5 meters per hour at the final stage of their activity. Sand flies had one peak in July which is strongly influenced by temperature and humidity conditions. Two species of Ph. kandelakii and Phlebotomus perfilewi transcaucasicus, had the highest activity in this endemic area.

Conclusion

The results of current study will provide a guideline for control of diseases in the country.