Maintenance of Lutzomyia longipalpis colonies using an artificial membrane blood-feeding method

Project background

Lutzomyia longipalpis is a blood-feeding sand fly and a vector of a number of viruses and species of the protozoan parasite Leishmania Leishmania parasites are causative agents of a group of neglected tropical diseases, Leishmaniases, of which visceral leishmaniasis is the most serious form. Approximately 500,000 people each year are affected by visceral leishmaniasis which is fatal if left untreated. There has been growing research into leishmaniasis which often requires the maintenance of a laboratory based sand fly colony. Female sandflies require a blood-meal to provide protein for egg production, which most commonly is provided by allowing sand flies to feed on an anaesthetised rodent.

Why we funded it

This Project Grant aims to develop a non-animal based feeding method for maintaining research colonies of Lutzomyia longipalpis to replace the use of anaesthetised rodents for feeding. 

Golden hamsters are anaesthetised and sand flies allowed to feed for 45 minutes before the hamster is removed. Hamsters are closely monitored to ensure they do not come out of the anaesthetised state during the feed. Minor irritation can be observed around the bite sites for approximately 24 hours post-feed. The hamster is not reused in the feeding protocol for two months.

Research methods

An artificial feeding system has previously been developed for a range of Leishmania parasites, using chick skin membranes. However, this system still relies on an animal product and there is a degree of variability in the numbers of female sand flies successfully feeding. This project will investigate potential artificial membranes, both biological and synthetic, for use in an in vitro blood feeding protocol. The protocol will be developed further by exploring the effects of various parameters on the success of the feed, such as blood source, room temperature and the presence of attractants. Efficiency of the feed will be assessed by comparing four performance measurements including the percentage of female sand flies that successfully feed, the number of eggs laid and subsequently hatch and the number of adult flies which emerge from pupa. 

The haematophagous sand fly, Lutzomyia longipalpis, is a vector of medical and veterinary importance and transmits Leishmania infantum, the causative agent of visceral leishmaniasis in the New World. Worldwide visceral leishmaniasis affects approximately 500,000 people each year, and is fatal if not treated. There has been growing research into the leishmaniases in the past decade, and often such research requires the rearing and maintenance of laboratory based sand fly colonies. The female sand flies require a blood-meal to provide protein for oviposition. At present the most common method of delivery for this blood-meal, is to allow female flies to blood-feed on an anaesthetised hamster.

Recently, alternative methods of artificial blood-feeding have been described using chick-skin membranes and chicken or horse blood with Phlebotomus papatasi sand flies. The viability of these methods has yet to be fully determined for Lutzomyia longipalpis. This research is designed to investigate the feasibility of developing and maintaining an artificial blood-feeding membrane system that would reduce, or replace the requirements for animals in this process.