| Disease/Syndrome |
Onchocerciasis |
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| Category |
Infection, Travel |
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| Acute/Chronic |
Chronic |
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| Synonyms |
River Blindness; Onchocerca volvulus; |
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| Biomedical References |
Search PubMed |
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| Comments |
FINDINGS: Adult filarial worms produce microfilariae that migrate through the skin (dermatitis and nodules) and into the eye (visual impairment and blindness). "Leopard skin" pigmentary changes appear on the lower extremities. The skin nodules containing adult worms are called "onchocercoma." Massive enlargement of inguinal and femoral lymph nodes may occur. [Merck Manual, p. 1549; CCDM, p. 387-91] Onchodermatitis has been classified as: 1) acute papular dermatitis; 2) chronic papular dermatitis; 3) lichenified dermatitis (Sowda); 4) atrophy; and 5) depigmentation. Sowda is a syndrome of hyperpigmented papules and plaques with associated regional lymphadenopathy. The most common symptom in expatriates is itching--an urticaria-like rash is often present on the trunk. Marked eosinophilia is associated with this infection. [Guerrant, p. 1180, 1482] Subcutaneous nodules are painless and 0.5-1 cm in size. Worms can live for up to 14 years in tissue. Sonography can distinguish between onchocercoma and other subcutaneous nodules. [Current Consult, p. 688] EPIDEMIOLOGY: Travelers at risk have lived in an endemic area for >3 months and worked near black fly habitats (flowing rivers). [CDC Travel, p. 255] |
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| Latency/Incubation |
About one year for larvae from bite of black fly to develop into adult worms; |
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| Diagnostic |
Skin biopsy; Slit-lamp examination; PCR; Antibody tests are limited by false positives, and they do not distinguish between past and acute infection. [CDC website] |
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| ICD-9 Code |
125.3 |
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| Effective Antimicrobics |
Yes |
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| Scope |
Central Africa and areas in the Arabian Peninsula (Yemen) and in South & Central America (Brazil, Columbia, Ecuador, Guatemala, southern Mexico, and Venezuela; |
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| Reference Link |
CDC - Onchocerciasis |
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| Related Information in Haz-Map |
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| Symptoms/Findings |
Symptoms/Findings associated with this disease:
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| Job Tasks |
High risk job tasks associated with this disease:
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