Interview with Patrick Lammie
Patrick J. Lammie, Ph.D.
Team Lead, Disease Elimination and Control Activity
Division of Parasitic Diseases/F13
Centers for Disease Control and Prevention
4770 Buford Highway
Atlanta, GA 30341

It seems that antibiotics affect filarial parasites in a variety of ways, but what is the primary biological significance of antibiotics to the treatment of onchocerciasis?

The biologic significance of the antibiotics is not related to treatment per se.  It is that is that the antibiotics demonstrate the symbiotic relationship between filarial worms and Wolbachia.  This raises many questions - how did this relationship develop? What are the bacteria providing to the worm?  Why is worm fertility dependent on the presence of Wolbachia?

What are the greatest challenges to employing antibiotics as a method of onchocerciasis treatment? How great of a concern is drug resistance?

I see several challenges to the use of antibiotics for treatment of onchocerciasis, though these are related.  Extended courses of antibiotic treatment are not realistic as a public health intervention because of the cost and logistic difficulties.  In addition, we know from clinical experience with use of antibiotics that compliance tends to decrease as the length of treatment increases.  The adverse events associated with prolonged antibiotic use (gastrointestinal upset, yeast infections, photosensitivity, etc.) also will pose problems.  

The possiblity that use of antibiotics for treatment of onchocerciasis will lead to the development of drug resistance by bacteria raises the theoretical concern that drug resistant bacteria will cause more morbidity and mortality than the onchocerciasis that we were treating.

Considering that the required length of treatment makes antibiotics unrealistic as a public health intervention, how do you perceive their potential role in onchocerciasis control efforts?

The role of antibiotics currently is limited; however, there are ongoing efforts to identify short courses of treatment that are still effective supressing microfilaria production. 

What are the prospects for future onchocerciasis treatments that target?

Information from the filarial genome project has provided the complete Wolbachia genomes as well.  From this, it may be possible to identify novel therapeutic targets that are Wolbachia-specific. 

What do you think are currently the greatest needs for the treatment and control of onchocerciasis?  Are there any potential solutions on the horizon?

There is a real need for a drug that will target the adult worm.  Because drugs that target Wolbachia must enter the worm, it may prove more realistic to target the worm than the endosymbiont.  Again, information from the genome project should help us here.