Host preferences of the sand fly Lutzomyia longipalpis at an endemic focus of American visceral leishmaniasis in Colombia.

The study examines the feeding preferences of the sand fly species, Lutzomyia longipalpis, that contributes to the spread of American visceral leishmaniasis in Colombia, demonstrating that these insects favor bovines and pigs.

Study Methodology and Objectives

• The research was conducted on 579 Lutzomyia longipalpis, a type of sand fly that play a role in the transmission of the disease, American visceral leishmaniasis.
• The insects were collected over a 16-month period from residential areas, a pigpen, and rock crevices in a small endemic community in Colombia known as El Callejon.
• A precipitin test, a method used in immunology to determine the source of antigens such as antibodies in a sample, was used to identify the sources of blood meals in the flies. This helped determine what animals the flies had been feeding on.

Data Analysis and Findings

• The feedings patterns of the sand flies were found to vary based on the location and collection date.
• Despite variability, bovine feeding was most common, with feedings also observed on pigs, equines, humans, dogs, opossums, birds, and reptiles.
• A forage ratio calculation (a measure that indicates the preference of a predator for different types of prey) used for each host species suggested that cows and pigs were the preferred hosts for Lu. longipalpis in the specific area of study.

Implications of the Study

• The results suggest the sand fly Lu. longipalpis is an opportunistic feeder, feeding on whatever host is most readily available rather than showing a particular preference.
• Contrary to prior assumptions, the flies were not highly anthropophilic (human-attracted) or strongly attracted to dogs.
• This data could impact control measures for American visceral leishmaniasis, as it indicates that efforts might be most effective if targeted at bovine and pig populations, rather than focusing solely on preventing bites on humans or dogs.