title: Diagnosis of O. volvulus infection via skin exposure to diethylcarbamazine: clinical evaluation of a transdermal delivery technology-based patch.
abstract: BACKGROUND
  Elimination of onchocerciasis in Africa is now regarded as an achievable goal in many areas. This makes monitoring changes in infection prevalence a key component of control programmes. Monitoring is currently based on determining the presence of O. volvulus microfilariae in skin snips, an invasive, labour-intensive method. The Onchocerciasis Control Programme (OCP) had established procedures to detect O. volvulus infections via the localized skin reaction induced by killing of microfilariae upon skin exposure to diethylcarbamazine via a patch (OCP-patch). Large scale OCP - patch use is difficult due to labour-intensive patch preparation. At the request of TDR, a manufacturer specialized in transdermal-delivery systems developed a ready-to-use diethylcarbamazine (DEC) containing patch (LTS-2 patch). To qualify this patch for large scale studies of its sensitivity and specificity, this study evaluated its ease of application, ability to detect infection and DEC exposure related adverse reactions compared to the OCP-patch in 30 infected individuals.
  
  
  METHODS
  Each participant with 0.2-36.8 O. volvulus microfilariae/mg skin received the OCP-patch and 4 days later the LTS-2 patch at the left and right iliac crest, respectively, for 24 h. Presence and characteristics of local skin reactions were assessed at patch removal and 6 h later. Skin reaction and Mazzotti reaction rates were compared with Fisher's exact and a paired t-test, respectively.
  
  
  RESULTS
  The LTS-2 patch could be applied within 10 s. Mild itching occurred at 63.3 % of OCP-patch (duration 8.9 ± 11.8 h) and 26.7 % of LTS-2 patch sites (duration 1.0 ± 2.5 h) and was the most frequent Mazzotti reaction. At patch removal after 24 h, a diagnostic local skin reaction was present under 90 % of OCP-patches and 83 % of LTS-2 patches; 6 h later, it was present at 93 % of OCP-patch and 100 % of LTS-2 patch sites.
  
  
  CONCLUSIONS
  The data suggest that safety, tolerability and ability to detect infections of the LTS-2 patch are comparable to those of the OCP-patch. They qualify the LTS-2 patch for field studies to determine LTS-2 patch sensitivity, specificity and utility during large scale use and thus to inform use of the LTS-2 patch by onchocerciasis control programmes to determine prevalence of infection.
  
  
  BACKGROUND
  Current controlled Trials ISRCTN76875372 .
authors.affiliation: Onchocerciasis Chemotherapy Research Centre, Hohoe, Ghana.
authors.forename: K
authors.initials: K
authors.lastname: Awadzi
authors.affiliation: Onchocerciasis Chemotherapy Research Centre, Hohoe, Ghana. opokuopn@hotmail.com.
authors.forename: Nicholas O
authors.initials: NO
authors.lastname: Opoku
authors.affiliation: Onchocerciasis Chemotherapy Research Centre, Hohoe, Ghana. skwakuattah@yahoo.com.|Department of Microbiology, University of Ghana Medical School, Accra, Ghana. skwakuattah@yahoo.com.
authors.forename: Simon K
authors.initials: SK
authors.lastname: Attah
authors.affiliation: UNICEF/UNDP/World Bank/ WHO Special Programme for Research and Training in Tropical Diseases, World Health Organization, Geneva, Switzerland. lazdinsj@gmail.com.
authors.forename: Janis K
authors.initials: JK
authors.lastname: Lazdins-Helds
authors.affiliation: UNICEF/UNDP/World Bank/ WHO Special Programme for Research and Training in Tropical Diseases, World Health Organization, Geneva, Switzerland. kuesela@who.int.
authors.forename: Annette C
authors.initials: AC
authors.lastname: Kuesel
mesh_terms: D000279:Administration, Cutaneous; D000293:Adolescent; D000328:Adult; D000818:Animals; D004049:Diethylcarbamazine / Q000008:administration & dosage* / Q000009:adverse effects; D005260:Female; D005369:Filaricides / Q000008:administration & dosage* / Q000009:adverse effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D017181:Onchocerca volvulus / Q000187:drug effects* / Q000502:physiology; D009855:Onchocerciasis / Q000188:drug therapy* / Q000469:parasitology / Q000517:prevention & control; D012867:Skin / Q000469:parasitology*; D055815:Young Adult
chemical_list: D005369:Filaricides; D004049:Diethylcarbamazine