Diagnosis, Treatment, and
Public Health Strategies of Tungiasis

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DIAGNOSTIC TESTS:

A definitive diagnosis depends on demonstration of the flea itself either through a mineral oil preparation or a skin biopsy of the suspected nodule. A histologic examination will reveal the flea's body in the intraepidermal cavity lined with an eosinophilic cuticle. The cavity may also contain the round/oval eggs and hollow, ring-like components of the flea's respiratory and digestive track. Inflammation is usually noted in the underlying dermis.

Sometimes, a fluid will ooze from the central opening of the nodule and T. penetrans eggs may be seen with a microscope.

Differential diagnosis may include fire ant bite, tick bite, scabies, creeping eruption, cercarial dermatitis, myiasis, folliculitis, or Dracunculiasis.



Microscopic findings of the epidermal cavity revealing the flea and egg remnants.
MANAGEMENT AND THERAPY:

Treatment consists of the physical removal of the flea by a sharp instrument. The residual cavity should then be surgically cleaned to remove its entire contents. Afterwards, an antibiotic ointment may be applied to prevent secondary infections.

Certain chemicals have also proven to be effective, including 4 percent formaldyhyde solution, chlorophenothane (DDT), chloroform, turpentine, and niridazole. These treatments do not physically remove the flea from the skin, however, and therefore don't result in quick relief. They also carry their own risk of morbidity.

Physical removal followed by antibiotic ointment and an anti-tetanus prophylaxis to prevent secondary infection (especially that of tetanus) is most effective.


EPIDEMIOLOGY:

Originally, the sand flea was only present in Latin American and the Caribbean. It was most likely introduced into Africa in 1873 by the infested crew and sand on board the ship Thomas Mitchell travelling from Brazil to Angola. Within 20 years, the flea spread from Angola to the West Coast of Africa and throughout the sub-Saharan region eventually to East Africa and Madagascar. In 1899, Indian soldiers brought the flea to Bombay, India and Karachi, Pakistan.

Today, Tunga penetrans is endemic to Latin America, the Caribbean, sub-Saharan Africa, India, and Pakistan.


Regions endemic with tungiasis marked in red.

In endemic areas, prevalence ranges from 15-40%. In 1981, the prevalence of tungiasis among children in rural Lagos State (Nigeria) recorded 40%. Similar prevalence was noted for villages in Southern Nigeria and Trinidad.

In other areas, however, cases are sporadic. Travelers may become infected in and import the flea from endemic areas. In the United States, only 14 cases have been reported since 1989.

Tungiasis has become a neglected health problem in poor communities.

"Growing urbanization, improved housing, and use of appropriate footwear presumably have led to an overall reduction of the occurrence of tungiasis in many Latin American and African countries. However, it is still a highly prevalent disease where people live in poverty, such as in the innumerable shantytowns of big cities of in the rural hinterland. Those areas share many factors favoring a high attack rate by T. penetrans: stray dogs and cats, pigs in close vicinity to living quarters, unpaved streets, mud floors in houses, insufficient or non-existent sanitation; and infestation with rats and mice especially in areas without rubbish disposal. Many people, especially children, mostly walk barefoot or only wear slippers. Illiteracy, ignorance, and neglect presumably are other factors favoring the high prevalence of severe pathology of children living in these circumstances. Tungiasis is a disease of the poor." (Heukelbach, 269)


PUBLIC HEALTH AND PREVENTION STRATEGIES:

Wearing of shoes is the primary defense against tungiasis. Shoes should be strongly encouraged to control the disease in all endemic areas.

Avoidance of contaminated areas, personal cleanliness, and disinfection of clothing, bedclothes, and furniture can also be important.

Floors/ground sprayed with an insecticide (1% Malathion) is also effective in reducing the incidence of tungiasis in infested villages.



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