title: Onchocerciasis: clinical presentation and host parasite interactions in patients of southern Sudan.
abstract: BACKGROUND
  Onchocerciasis, an infection by the filarial nematode Onchoverca volvulus, is widely distributed in tropical Africa and of great dermatologic interest. This study analyses the dermatologic presentation and tries to determine the correlations between clinical disease and host parasite interactions in onchocerciasis patients of the Southern Sudan.
  
  
  METHODS
  We performed clinical and histopathologic investigations in patients with onchocerciasis in the Wau District, Bahr el Ghazal Province, Southern Sudan. As well as a detailed clinical skin examination, skin biopsies were taken, processed, and investigated for type and degree of host tissue response. Parasitologic, clinical, and histopathologic findings were evaluated.
  
  
  RESULTS
  Onchocerciasis appears with a variety of severe skin lesions. Central is a pruritic rash. Long-standing cases develop extensive pigmentary changes and impressive signs of skin tissue exhaustion. Cellular host tissue responses to degenerating skin microfilariae seem to play a key role in the development of skin pathology. The degree of host response appears to be inversely proportional to the host's microfilarial load.
  
  
  CONCLUSIONS
  Onchocerciasis represents a health problem of great dermatologic importance in Southern Sudan. The study results demonstrate clinical variations in onchocerciasis and provide support for the existence of a disease spectrum.
authors.affiliation: National Leprosy Training Centre, Wau, Southern Sudan.
authors.forename: P
authors.initials: P
authors.lastname: Stingl
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D002648:Child; D005260:Female; D006790:Host-Parasite Interactions / Q000502:physiology*; D006801:Humans; D007303:Insect Vectors; D008297:Male; D017181:Onchocerca volvulus / Q000302:isolation & purification; D009855:Onchocerciasis / Q000175:diagnosis* / Q000469:parasitology / Q000473:pathology; D012843:Simuliidae / Q000469:parasitology; D012867:Skin / Q000469:parasitology*; D012876:Skin Diseases, Parasitic / Q000175:diagnosis* / Q000469:parasitology / Q000473:pathology; D013397:Sudan