Application of image analysis in the evaluation of blood feeding by Lutzomyia longipalpis using an artificial feeding system with synthetic membranes.

BACKGROUND

Blood feeding is essential for the maintenance of laboratory colonies and for experimental studies involving sand fly-parasite interactions. However, artificial feeding systems for Lutzomyia longipalpis, the principal vector of Leishmania infantum, the etiological agent of visceral leishmaniasis in the Americas, remain limited by low engorgement rates and methodological constraints in blood meal quantification.

OBJECTIVES

This study evaluated the feeding performance of Lu. longipalpis on different membranes in an artificial feeder and applied an image-based approach to quantify blood meal size.

METHODS

Females were fed either on anaesthetised hamsters (in vivo control) or using a Hemotek® artificial feeder equipped with chick skin (CHK), hydrated collagen membrane treated with plasma gel (COL+PG), or untreated hydrated collagen membrane (COL). Blood meal size was estimated through digital image analysis in Fiji/ImageJ using two regions of interest: whole abdomen area (AbdA) and red-coloured blood area (BldA).

FINDINGS: Feeding rates were highest on live hosts (88.75%), followed by CHK (72.34%) and COL+PG (72.08%), whereas COL yielded significantly lower engorgement (54.67%). Although abdominal area was greater in females fed on hamsters, no significant differences in red-coloured area were detected among artificial membrane treatments. A strong positive correlation was observed between AbdA and BldA measurements (R² = 0.85), validating the image-based method. The use of plasma-treated collagen membranes achieved feeding rates comparable to CHK and was fully compatible with semi-automated image analysis.

MAIN

CONCLUSIONS

These findings demonstrate that hydrated collagen membranes treated with plasma gel constitute a viable and ethically preferable alternative to bird-derived membranes for the artificial feeding of Lu. longipalpis, while image analysis provides a precise, reproducible, and practical method for blood meal quantification. Collectively, this approach refines laboratory experiments Lu. longipalpis and enhances methodological reliability in studies of sand fly biology and vector-parasite interactions.