3.3

Sand fly bite 

Note: this video has no sound.

In this video we watch a female sand fly of the species Lutzomia longipalpis (most commonly found in South America), taking a blood meal from a human host volunteer.

The sand fly starts feeding by piercing with her mouthparts (known as the proboscis) into a human host’s skin (less than 1 mm deep). The blood pools in the wound from which the sand fly feeds. To aid feeding the sand fly salivates from its mouth parts. The saliva contains components, such as vasodilators, which help blood to flow and reduce irritation [1, 2]. However, the bites of sand flies are reportedly painful and can form a small red blister at the bite site at the site.

The blood is ingested directly into the sand fly’s midgut where it is digested. In the video, we can clearly see the sand fly’s gut filling with blood over time. The taking of a full blood meal of an uninfected sand fly lasts for approximately 1 – 3 minutes. The size of the sand fly gut almost triples in size.

Generally, one blood meal is needed to produce one batch of eggs. Female sand flies can lay between 30 to 70 eggs in a gonotrophic cycle. Female sand flies tend to seek blood meals every 5 to 6 days as it essential for egg development. On average, a sand fly will digest full blood meal in 2 to 3 days, depending on sand fly species, environmental conditions and breeding habit.

Most species feed at dusk and during the night as temperatures fall and humidity rises [3]. However, biting may also occur during the day in forests and some dark or shaded habitats . Most sandfly species feed outdoors though some will bite at indoor sites.

Notes:

  1. Ethical clearance for the production of this video was granted prior to filming

  2. This video does not contain narration or audio

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This video is from the free online course:

Control and Elimination of Visceral Leishmaniasis

London School of Hygiene & Tropical Medicine