Assessing Survival of Transgenic Bacteria, Serratia AS1 and Enterobacter cloacae, in Sugar Bait, White Saxaul Plant (Haloxylon persicum) and Rodent Barrow's Soil, A Contained-Field Study for Paratransgenesis Approach.

Background: The viability and persistence of engineered bacterium candidates in field conditions is one of the considerable challenges in the paratransgenesis approach to fighting vector-borne diseases. Methods: In this study two engineered bacterium candidates to produce paratransgenic sand flies, Serratia AS1 and Enterobacter cloacae expressing m-Cherry fluorescent were applied on the leaves of the white saxaul plant (Haloxylon persicum), sugar bait, and rodent burrow soil and their persistent time was tested in desert condition, Matin Abad County, Isfahan, August 2022. A PBS suspension of 109 cells/ml was used for sugar bait, spraying on plant leaves (∼10 cm2) and 10 cm2 of rodent burrow soil. Sand fly samples were taken daily and were plated on LB Agar and the fluorescent cells were counted after 24 hours. Results: Time course in general caused a decrease in the number of bacteria for both strains. The two strains were persistent in sugar bait and on plant leaves for four days and on soil for two days. Although there were slight differences between the number of the bacteria in sugar baits, which was not significant (P< 0.05). The number of E. cloacae surviving on plant and in soil were significantly (P< 0.0001 and P= 0.046) higher than Serratia AS1. Conclusion: This study shows that plants or sugar bait are useful routes for delivery of the transformed bacteria for the paratransgenesis approach, although, the bacteria ought to be sprayed on plants or sugar baits should be replaced with new ones in four days intervals.

A Comparative Study on the Biodiversity and Species Richness of Phlebotomine Sand Flies (Diptera: Psychodidae) in Kermanshah and Khuzestan Provinces of Iran.

Background: Leishmaniasis is one of the most important vector-borne and neglected tropical diseases in many parts of the world. The main objective of this study was to determine the biodiversity of phlebotomine sand flies (Diptera: Psychodidae, Phlebotominae) in Khuzestan and Kermanshah Provinces of Iran. Methods: Sampling was conducted in Khuzestan and Kermanshah Provinces using sticky paper traps and CDC light traps. The samples were then stored in 96% alcohol-containing vials, mounted, and identified. Afterward, the alpha diversity (using Simpson's, Shannon-Weiner's diversity, evenness, Maghalef's, Menhinick's, Hill N 1 and N 2 indices) and beta diversity indices (using Sorensen's and Jaccard's coefficients) were calculated. Results: A total of 4302 sand flies were caught and identified which comprised mostly of Phlebotomus papatasi, Ph. alexandri and Ph. sergenti. It was found that among the four counties of Ahvaz, Shush, Shushtar and Dezful in Khuzestan Province, Shush had the lowest, and Shushtar, the highest amount of species diversity and evenness. In the four studied counties of Kermanshah Province, species diversity in Kermanshah County had the lowest amount and Sarpol-e-Zahab, the highest. The species richness in Kermanshah County was the lowest, while Qasr-e-Shirin County had the highest amount. Conclusion: An overview of the biodiversity of phlebotomine sand flies in Kermanshah County in Kermanshah Province, and Shush County in Khuzestan Province, showed less stability in community structure of these vectors, which can be counted as an alarm for emerging dominant vectors among the studied counties and have the potential to increase the prevalence of leishmaniasis.