Efficacy of 5-week doxycycline treatment on adult Onchocerca volvulus.
The effects of 5-week doxycycline treatment on the depletion of Wolbachia endobacteria from Onchocerca volvulus, on the interruption of embryogenesis and on microfilariae production, and with regard to macrofilaricidal activity were studied. In 2003, in an endemic area in Ghana, 22 onchocerciasis patients received 100 mg/day doxycycline for 5 weeks. Two years after the start of the study, 20 treated and ten untreated patients were nodulectomized and skin microfilariae were counted. The onchocercomas were examined by immunohistology for the presence of Wolbachia, embryogenesis, and vitality of adult filariae. The latter two parameters were further assessed by alternating logistic regression analysis, taking into account the dependency of worms and nodules in patients. Doxycycline resulted in depletion of Wolbachia and in complete interruption of embryogenesis in all worms that were assumed to have been present during treatment. In the treated patients, only 51% of the female worms were alive, compared to 84% in the untreated patients, indicating a moderate but distinct macrofilaricidal activity of doxycycline at this dose. It is concluded that, in areas with ongoing transmission, doxycycline cannot replace regular ivermectin mass treatment because new infections would require repeated rounds of doxycycline. However, doxycycline can be used for the treatment of individuals outside transmission areas, in foci where ivermectin resistance may occur, and in countries where onchocerciasis and loiasis are co-endemic.
Hoerauf
Achim
A
Institute for Medical Microbiology, Immunology and Parasitology, University of Bonn, Sigmund-Freud-Str. 25, 53105 Bonn, Germany. hoerauf@parasit.meb.uni-bonn.de
Specht
Sabine
S
Marfo-Debrekyei
Yeboah
Y
Büttner
Marcelle
M
Debrah
Alexander Yaw
AY
Mand
Sabine
S
Batsa
Linda
L
Brattig
Norbert
N
Konadu
Peter
P
Bandi
Claudio
C
Fimmers
Rolf
R
Adjei
Ohene
O
Büttner
Dietrich W
DW
D000293:Adolescent; D000328:Adult; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D004318:Doxycycline / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D005369:Filaricides / Q000008:administration & dosage / Q000627:therapeutic use*; D005869:Ghana; D006801:Humans; D008297:Male; D008875:Middle Aged; D017181:Onchocerca volvulus / Q000382:microbiology* / Q000502:physiology*; D009855:Onchocerciasis / Q000188:drug therapy*; D012867:Skin / Q000469:parasitology / Q000473:pathology; D016019:Survival Analysis; D020577:Wolbachia / Q000187:drug effects*; D055815:Young Adult
D000900:Anti-Bacterial Agents; D005369:Filaricides; D004318:Doxycycline