This week's case is of a middle-aged man with a painful lesion on the dorsum of his foot. He recently returned from Brazil, during which he swam in the ocean, walked barefoot on the beach, and ate local foods. An excisional biopsy was performed and submitted to the clinical microbiology lab to rule out a possible parasite. The specimen received was an excised ellipse of skin on which there was a central defect measuring ~ 5 mm in diameter:
To confirm our suspected diagnosis, we serially sectioned the skin and submitted the sections for histopathologic processing. Here are a couple of images from the H&E stained slides (using the 4x and 10x objectives):
Identification?
8 comments:
Tunga penetrans??
From the history and clinical symptoms, my suspicion is that while walking barefoot on the beach, the gentleman met “una chica”, not the two legged kind but the one of the kind you would find on cats, dogs, rats or rarely humans. The encounter resulted from the burrowing of the flea and the ovoid objects are her eggs. So I would go with Tunga penetrans being the perpetrator of the man’s misery.
My apologies, I forgot to sign my response.
Florida Fan
Tunga sp.
Indeed, it could be Tunga penetrans but we might be more cautious by talking about Tunga sp. as there are 12 species of Tunga (De Averlar et al. 2013).
Until now, only T. penetrans and T. trimamillata have been found parasitizing humans and domestic animals.
T. penetrans is largely present in Latin America (including the Caribbean islands), and in sub-Saharan Africa, while T. trimamillata is known from Equator, Peru and Brazil (Pampiglione et al. 2004, 2009; Linardi et al. 2013).
The painful lesion (Photo 1) is most probably the result of not proper removal from or squeezing of the flea inside the skin, which lead to secondary infections and wound.
The second and third photos are off-course the eggs in the body of the female.
In the lower part of the fourth photo we see several striated muscles, most probably of the third leg of the flea which are used (while free in the environment) to jump.
The last photo shows most probably a cut of the intestine with human erythrocytes.
References:
- De Avelar et al. 2013. A New Species of Tunga (Siphonaptera: Tungidae) Parasitizing Cattle From Brazil
J. Med. Entomol. 50(4): 679-684 (2013); DOI: http://dx.doi.org/10.1603/ME12221
- Linardi, P.M., De Avelar, D.M. & Facury Filho, E.J. Establishment of Tunga trimamillata (Siphonaptera: Tungidae) in Brazil. Parasitol Res 112, 3239–3242 (2013). https://doi.org/10.1007/s00436-013-3501-5
- Pampiglione, S., M. Trentini, M. L. Fioravanti, and A. Gustinelli. 2004. Differential diagnosis between Tunga penetrans (L., 1758) and T. trimamillata Pampiglione et al.,2002 (Insecta, Siphonaptera), the two species of the genus Tunga parasitic in man. Parasite 11: 51-57.
- Pampiglione, S., M. L. Fioravanti, A. Gustinelli, G. Onore, B. Mantovani, A. Luchetti, andM. Trentini. 2009. Sand flea (Tunga spp.) infections in humans and domestic animals: state of the art. Med. Vet. Entomol. 23: 172-186.
I agree with the hypothesis of tungiasis, probably caused by Tunga penetrans. Eggs are expelled at incredible speeds.
Tunga penetrans eggs. I'm pretty sure the beach was a clue.....
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