Gnathostomiasis Acquired by British Tourists in Botswana

Joanna S. Herman; Emma C. Wall; Christoffer van Tulleken; Peter Godfrey-Faussett; Robin L. Bailey; Peter L. Chiodini

Disclosures

Emerging Infectious Diseases. 2009;15(4):594-597. 

In This Article

The Cases

The first person evaluated for possible gnathostomiasis was a British Caucasian man, 41 years of age, who came to the Hospital for Tropical Diseases (HTD) in London on September 30, 2008, 3 weeks after his return from the Okavango Delta in Botswana. He had been camping, walking barefoot, and swimming in and drinking river water. On several occasions, he had also eaten raw bream. About 2 weeks later, he reported intermittent abdominal discomfort, which was localized, but each morning, the pain moved to a different site and was accompanied by a palpable swelling over his spleen that resolved after 12 days. Pruritus then developed under his left arm and, within 24 hours, a painful subcutaneous lump developed on his anterior chest wall.

When he arrived at HTD, he was systemically well but had a raised nontender erythematous lesion below his left axilla. His eosinophil count was slightly high, 0.69 x 109 cells/L (reference count < 0.4 x 109 cells/L).

A presumptive diagnosis of migratory helminthic infection was made (gnathostomiasis or larval cestode infection), and he was treated with ivermectin, 200 mg/kg as a single dose, and albendazole, 400 mg 2x/d for 21 days. A week later, the lesion had migrated to his neck, but within 14 days, the lesion and eosinophilia had resolved. His initial serologic test result was negative for Gnathostoma spp. A subsequent sample was also negative, which may indicate that the antibody response had not developed sufficiently or that results were outside the sensitivity range.

A second British Caucasian man came to HTD on October 11, 2008, eleven days after the patient previously described, and 5 weeks after the new patient's return from the same trip in Botswana, where he had consumed the same foods and participated in the same activities. An erythematous, edematous, and pruritic lump (2 cm) developed above his left groin, lasted 4 days, and then subsided. As the lump decreased in size, he noticed a histamine-type track (left by a larva moving through tissue) toward his ribcage. One week later, the track mark had moved further up his chest. After another week, he reported a swollen, warm, and itchy right knee, which resolved within 24 hours, but 7 days later, similar symptoms developed in his right ankle.

He visited HTD again with a serpiginous, raised lesion on his back and surrounding erythema and eosinophilia (0.9 x 109 cells/L). He was treated empirically with albendazole, 400 mg 2x/d for 21 days, and praziquantel, 20 mg/kg as a single dose, for presumptive diagnosis of helminthic infection. Over the next 6 days, the serpiginous lesion migrated over his shoulder and neck, disappeared for 24 hours, then reappeared between his eyebrows, moved to his forehead and face, and then was felt inside his nose (Figure 1). On day 6, a spot developed below his left nostril, from which he expressed a larva. He brought it to HTD, where it was identified as Gnathostoma spinigerum.

Figure 1.

Cutaneous larva migrans on the forehead (A) and shoulder (B) of a male British tourist who had visited Botswana.

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