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. 2020 May 15;13(1):258.
doi: 10.1186/s13071-020-04126-x.

Individuals living in an onchocerciasis focus and treated three-monthly with ivermectin develop fewer new onchocercal nodules than individuals treated annually

Jérémy T Campillo  1 , Cédric B Chesnais  1 , Sébastien D S Pion  1 , Jacques Gardon  2 , Joseph Kamgno  3   4 , Michel Boussinesq  5
Affiliations
Free PMC article

Individuals living in an onchocerciasis focus and treated three-monthly with ivermectin develop fewer new onchocercal nodules than individuals treated annually

Jérémy T Campillo et al. Parasit Vectors. .
Free PMC article

Abstract

Background: Little information is available on the effect of ivermectin on the third- and fourth-stage larvae of Onchocerca volvulus. To assess a possible prophylactic effect of ivermectin on this parasite, we compared the effects of different ivermectin regimens on the acquisition of onchocercal nodules.

Methods: We analyzed data from a controlled randomized clinical trial of ivermectin conducted in the Mbam Valley (Cameroon) between 1994 and 1998 in a cohort of onchocerciasis infected individuals. The number of nodules that appeared between the start and the end of the clinical trial was analyzed, using ANOVA and multivariable Poisson regressions, between four treatment arms: 150 µg/kg annually, 800 µg/kg annually, 150 µg/kg 3-monthly, and 800 µg/kg 3-monthly.

Results: The mean number of nodules that appeared during the trial was reduced by 17.7% in subjects treated 3-monthly compared to those treated annually (regardless of the dose). Poisson regression model, adjusting on subject's age and weight, initial number of nodules and intensity of O. volvulus infection in his village of residence, confirmed that the incidence of new nodules was reduced in 3-monthly treatment arms compared to annually treatment arms, and that the dosage of ivermectin does not seem to influence this effect. Furthermore, the number of newly acquired nodules was positively associated with the initial number of nodules. Analysis of disappearance of nodules did not show any significant difference between the treatment groups.

Conclusions: To our knowledge, these results suggest for the first time in humans, that ivermectin has a partial prophylactic effect on O. volvulus. Three-monthly treatment seems more effective than annual treatment to prevent the appearance of nodules.

Keywords: Cameroon; Ivermectin; Nodules; Onchocerca volvulus; Onchocerciasis; Onchocercoma.

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Figures

Fig. 1
Fig. 1
Statistical analysis plan
Fig. 2
Fig. 2
Predicted number of new nodules vs initial number of nodules (annual vs 3-monthly arms). Bars indicate the 95% confidence interval
Fig. 3
Fig. 3
Predicted number of new nodules vs initial number of nodules (four treatment arms). Bars indicate the 95% confidence interval
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References

    1. Lämmler G. Experimental chemotherapy and chemoprophylaxis of filariasis. Pestic Sci. 1977;8:563–576. doi: 10.1002/ps.2780080523. - DOI
    1. Bain O, Babayan S. Behaviour of filariae: morphological and anatomical signatures of their life style within the arthropod and vertebrate hosts. Filaria J. 2003;2:1–12. doi: 10.1186/1475-2883-2-16. - DOI - PMC - PubMed
    1. Taylor HR, Trpis M, Cupp EW, Brotman B, Newland HS, Soboslay PT, et al. Ivermectin prophylaxis against experimental Onchocerca volvulus infection in chimpanzees. Am J Trop Med Hyg. 1988;39:86–90. doi: 10.4269/ajtmh.1988.39.86. - DOI - PubMed
    1. Tchakouté VL, Bronsvoort M, Tanya V, Renz A, Trees AJ. Chemoprophylaxis of Onchocerca infections: in a controlled, prospective study ivermectin prevents calves becoming infected with O. ochengi. Parasitology. 1999;118:195–199. doi: 10.1017/S0031182098003680. - DOI - PubMed
    1. Boussinesq M, Chippaux JP. A controlled prospective trial of the prophylactic effect of a single dose of ivermectin against onchocerca volvulus. Parasite. 2001;8:255–259. doi: 10.1051/parasite/2001083255. - DOI - PubMed