Jiggers, scientifically known as Tunga penetrans, are a type of parasitic flea. These tiny insects, measuring about 1 millimeter in length, can cause a skin infestation called tungiasis. While they are sometimes confused with chiggers, which are mites, jiggers are distinct as they belong to the flea order Siphonaptera. Infestation by the female jigger can lead to various health concerns for humans and other mammals.
Global Presence
Jiggers are primarily found in tropical and subtropical regions. They are particularly widespread in sub-Saharan Africa, where they have become a public health concern. Their presence extends to parts of Latin America, including Central and South America, and the Caribbean. Historically, Tunga penetrans originated in the West Indies and South America, spreading to other tropical areas through various means, including shipping routes.
Understanding Their Life Cycle
The life cycle of the jigger, like most fleas, involves four main stages: egg, larva, pupa, and adult. Adult female jiggers, after burrowing into a host, lay small eggs (about 0.6 mm long) that are expelled onto soil or sand. Within one to six days, given adequate moisture and humidity, these eggs hatch into free-moving larvae that feed on organic debris. Larvae progress through two stages, typically taking three to four weeks to complete their development before entering the pupal phase. The jigger forms a cocoon, often covered with environmental debris like sand or pebbles, and this pupal stage can last for several days to weeks, protecting the developing flea until adults emerge to seek hosts and reproduce.
How They Infest Humans
Human infestation occurs when the adult, mated female jigger burrows into the skin. This penetration typically happens on areas of the body that come into direct contact with contaminated soil or sand, most commonly the feet. Preferred sites for burrowing include the spaces between the toes, under the toenails, or on the soles of the feet. The female jigger does not possess specialized organs for burrowing; instead, she uses her mouthparts and claws to penetrate the epidermis. Once embedded, only the posterior end of her abdomen remains exposed, allowing for respiration, mating, and the expulsion of eggs.
Conditions for Their Prevalence
Jiggers thrive in specific environmental and socioeconomic conditions that facilitate their life cycle and transmission. Warm, dry environments with sandy or dusty soil are ideal habitats for Tunga penetrans, where larvae and pupae often develop in dry, shaded soils, particularly inside houses with unsealed earthen floors. The prevalence of jiggers is associated with resource-poor communities. Inadequate housing (including cracked or dirty floors), a lack of access to clean water and sanitation, and poor personal hygiene (including not wearing shoes regularly) contribute to their widespread presence and increase the risk of infestation. The presence of domestic animals like pigs, dogs, and cats, which can act as reservoirs for the fleas, further contributes to human infestation in these communities.