A recent collaboration has been established to combat river blindness and lymphatic filariasis, two debilitating diseases caused by parasitic worms transmitted to humans by insects. The collaboration involves Prof. Achim Hoerauf and his team from the Institute of Medical Microbiology, Immunology, and Parasitology at the University Hospital Bonn, along with partners from the Department of Pharmaceutical Technology and Biopharmacy at the University of Bonn and the Helmholtz Center for Infection Research (HZI). Additionally, the Japanese pharmaceutical company Eisai is part of this initiative.
River blindness, caused by the parasitic worm Onchocerca volvulus, is transmitted through the bite of the blackfly and leads to severe itching, skin disfigurement, and potentially permanent blindness. Globally, an estimated 169 million people are at risk, with 99% of those at risk living in Africa. LF, caused by the parasitic worms Wuchereria bancrofti, Brugia malayi, and Brugia timori, is transmitted by mosquitoes and results in elephantiasis, a severe swelling of the limbs and genitalia, leading to disability and a significantly reduced quality of life. Approximately 120 million people are infected with LF, and 1.23 billion are at risk, predominantly in Africa and parts of Asia.
River Blindness and Lymphatic Filariasis
River Blindness (Onchocerciasis): Caused by the parasitic nematode worm Onchocerca volvulus, river blindness is transmitted by blackflies breeding in fast-flowing rivers. The disease can lead to severe itching, disfiguring skin conditions, and even blindness. Efforts to eliminate river blindness are challenged by co-infections like Loiasis.
Lymphatic Filariasis (Elephantiasis): This disease, caused by filarial parasites transmitted through mosquitoes, can lead to lymphoedema, elephantiasis, and scrotal swelling. It causes long-term suffering and chronic illness, contributing to stigma, poverty, and disability.
The collaboration aims to develop a safe and effective drug against these worm diseases. Corallopyronin A (CorA), an antibiotic with potential against these worms, is being studied. It targets bacteria essential for worm survival, leading to their destruction.
CorA has shown efficacy against filariae, and preclinical testing is in its final stages. The first clinical trials are scheduled for 2025/2026. The drug is being produced in compliance with Good Manufacturing Practice (GMP) standards for toxicity testing.
The project has received €5.6 million from the Japanese Global Health Innovative Technology (GHIT) Fund. This funding will support the production of CorA and the necessary safety assessments for human treatment.
Symptoms
The main symptoms of river blindness (onchocerciasis) and lymphatic filariasis are:
River Blindness (Onchocerciasis)
- Visual impairment and blindness
- Severe itching
- Dermatitis
- Nodules under the skin around adult worms
Short-term loss of vision that can be reversed with early treatment, but permanent blindness if larvae have been in the eyes for some time
When microscopic larvae die in the body, it can trigger an intense inflammatory reaction leading to immense discomfort. Larvae that die in the eyes can damage the cornea or optic nerve, causing permanent sight loss and blindness.
Lymphatic Filariasis
- Lymphoedema
- Elephantiasis
- Scrotal swelling
- Long-term suffering and chronic illness
- Both diseases can lead to stigma, poverty and disability
Over 99% of infected people live in 31 countries in sub-Saharan Africa. Onchocerciasis is also transmitted in parts of South America and Yemen.
Treatment
To combat these diseases, PATH and Standard Diagnostics (SD)/Alere have developed rapid diagnostic tools for onchocerciasis and LF. These antibody-based tests are designed for disease surveillance and are part of a broader suite of diagnostic innovations aimed at supporting the elimination of NTDs. The tests are particularly useful for monitoring post-control areas and detecting cases in low-prevalence areas, contributing to the elimination phase of control programs. The development of these tools reflects a commitment to enhancing surveillance capabilities and improving the effectiveness of control and elimination efforts.
The Carter Center has played a pivotal role in the fight against river blindness and LF, working closely with the Pan American Health Organization (PAHO) and other partners to eliminate these diseases from the Americas. The Center’s River Blindness Program, in collaboration with the Mectizan Donation Program of Merck & Co., Inc., has been instrumental in interrupting the transmission of river blindness in several countries, including Colombia, which became the first country to interrupt transmission on a national level. The Carter Center’s efforts have also extended to Africa, where it has supported the elimination of river blindness in several countries, including Uganda, which has made significant strides towards eliminating the disease nationwide.
Moreover, the Carter Center, in partnership with The Global Institute for Disease Elimination (GLIDE), aims to eliminate river blindness, LF, and malaria in the Americas, highlighting the collaborative nature of efforts to combat these diseases. The partnership underscores the importance of integrated approaches to disease elimination, leveraging resources and expertise to maximize impact.
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References
- https://www.cartercenter.org/health/lf/staff.html
- https://tdr.who.int/our-work/research-for-implementation/neglected-tropical-diseases-research/onchocerciasis-and-lymphatic-filariasis-research
- https://www.reachingthelastmile.com/our-work/river-blindness/
- https://www.path.org/our-impact/media-center/innovative-partnership-brings-to-market-new-tools-for-neglected-tropical-diseases/
