Hunger tolerance and Leishmania in sandflies

Area of Science:

• Vector-borne disease ecology
• Parasitology
• Entomology

Background:

• Phlebotomus papatasi sandflies transmit Leishmania major, causing cutaneous leishmaniasis in arid Old World regions.
• Seasonal dehydration and heat stress reduce plant sugar, impacting sandfly survival and pathogen transmission.
• Flies relying on plant sugars face survival challenges, potentially linking hunger tolerance with pathogen susceptibility.

Purpose of the Study:

• To investigate the relationship between sugar deprivation tolerance and Leishmania major susceptibility in Phlebotomus papatasi.
• To determine if selection for traits advantageous for survival in harsh environments increases pathogen susceptibility.

Main Methods:

• Comparing Leishmania major susceptibility in sandflies selected for sugar deprivation tolerance.
• Assessing sandfly susceptibility from both irrigated and arid habitats.
• Evaluating the link between physiological stress tolerance and parasite infection.

Main Results:

• Sandflies selected for sugar deprivation exhibited increased susceptibility to Leishmania major.
• Flies from arid habitats showed a correlation between hunger tolerance and higher pathogen loads.
• Evidence suggests a trade-off between survival under resource scarcity and resistance to infection.

Conclusions:

• Hunger tolerance in Phlebotomus papatasi, an adaptation to arid conditions, is associated with increased susceptibility to Leishmania major.
• This finding highlights a potential mechanism where environmental pressures shape vector competence and disease transmission dynamics.
• Understanding these trade-offs is crucial for predicting and managing leishmaniasis spread in changing climates.