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Onchocerciasis
Diagnostic Methods
Diagnostic methodsPros and cons
Parasitological diagnosis 
The classical way to diagnose onchocerciasis is by taking skin snips (six or more) and detecting microfilariae. However, the sensitivity is restricted in light infections (e.g. in drug- or vector-controlled areas).
  • Sensitivity is low in light infections
  • Taking skin snips is an invasive method and not well accepted
Molecular diagnosis 
Molecular methods have been described to demonstrate strain differences (e.g. between forest and savannah). In addition, infective larvae from related species can be differentiated from O. volvulus.
Detecting DNA in skin snips may improve sensitivity but needs biopsies.
  • Molecular methods are useful for special diagnostic aims
Antigen detection 
A new antigen detection dipstick method has been described which showed high sensitivity when urine samples were tested. Specificity also seems to be excellent.
  • Simple test format
  • No need to take skin snips
  • Better sensitivity than microscopy
  • Not yet standardized and commercially available
Antibody detection 
Many attempts have been undertaken to improve specificity of serological methods by using recombinant antigens. However, a decrease in sensitivity has often been observed. In a rapid format card test, IgG4 antibodies have been detected using the Ov16 recombinant antigen.
  • No need to take skin snips
  • Long persistence of antibodies in “dying-out” infections
  • Not yet standardized and commercially available