Onchocerciasis or river blindness is a parasitic disease caused by the filarial worm Onchocerca volvulus transmitted by repeated bites of infected blackflies (Simulium spp.). These blackflies breed along fast-flowing rivers and streams, close to remote villages located near fertile land where people rely on agriculture.
In the human body, the adult worms produce embryonic larvae (microfilariae) that migrate to the skin, eyes and other organs. When a female blackfly bites an infected person during a blood meal, it also ingests microfilariae which develop further in the blackfly and are then transmitted to the next human host during subsequent bites.
Onchocerciasis is an eye and skin disease. Symptoms are caused by the microfilariae, which move around the human body in the subcutaneous tissue and induce intense inflammatory responses when they die. Infected people may show symptoms such as severe itching and various skin changes. Infected people may also develop eye lesions which can lead to visual impairment and permanent blindness. In most cases, nodules under the skin form around the adult worms.
Onchocerciasis occurs mainly in tropical areas. More than 99% of infected people live in 31 countries in sub-Saharan Africa: Angola, Benin, Burkina Faso, Burundi, Cameroon, Central African Republic, Chad, Republic of Congo, Cte dIvoire, Democratic Republic of the Congo, Equatorial Guinea, Ethiopia, Gabon, Ghana, Guinea, Guinea-Bissau, Kenya, Liberia, Malawi, Mali, Mozambique, Niger, Nigeria, Rwanda, Senegal, Sierra Leone, South Sudan, Sudan, Togo, Uganda, United Republic of Tanzania.
Onchocerciasis is also transmitted in the Yanomami area of Brazil and Venezuela (Bolivarian Republic of) as well as in Yemen.
Between 1974 and 2002, disease caused by onchocerciasis was brought under control in West Africa through the work of the Onchocerciasis Control Programme (OCP), using mainly the spraying of insecticides against blackfly larvae (vector control) by helicopters and airplanes. This was later supplemented by large-scale distribution of ivermectin since 1989.
The OCP relieved 40 million people from infection, prevented blindness in 600 000 people, and ensured that 18 million children were born free from the threat of the disease and blindness. In addition, 25 million hectares of abandoned arable land were reclaimed for settlement and agricultural production, capable of feeding 17 million people annually.
The African Programme for Onchocerciasis Control (APOC) was launched in 1995 with the objective of controlling onchocerciasis in the remaining endemic countries in Africa and closed at the end of 2015 after beginning the transition to onchocerciasis elimination. Its main strategy was the establishment of sustainable community-directed treatment with ivermectin (CDTI) and vector control with environmentally-safe methods where appropriate. In APOCs final year, more than 119 million people were treated with ivermectin, and many countries had greatly decreased the morbidity associated with onchocerciasis. More than 800,000 people in Uganda and 120,000 people in Sudan no longer required ivermectin by the time that APOC closed.
In 2016, the Expanded Special Project for the Elimination of Neglected Tropical Diseases in Africa (ESPEN), was set up to cover the five preventive chemotherapy NTDs with 4 core objectives:
1. Scale up treatments towards the achievement of 100% geographic coverage, 2. Scale down: stopping treatments once transmission has been interrupted or control achieved, 3. Strengthen information systems for evidence-based action, and 4. Improve the effective use of donated medicines through enhance supply chain management. ESPEN is housed in the WHO Regional Office for Africa.
With support from ESPEN, ivermectin treatments continued to scale up, reaching 152.9 million people in 2019, but due to COVID-19 disruptions, the number of people treated declined by 26.9% in 2020.
The Onchocerciasis Elimination Program of the Americas (OEPA) began in 1992 with the objective of eliminating ocular morbidity and interruption of transmission throughout the Americas by 2015 through biannual large-scale treatment with ivermectin. All 13 foci in this region achieved coverage of more than 85% in 2006, and transmission was interrupted in 11 of the 13 foci. Elimination efforts are now focused on the Yanomami people living in Brazil and Venezuela (Bolivarian Republic of), representing a total population at risk of only 35,228 people.
On 5 April 2013, the Director-General of WHO issued an official letter confirming that Colombia has achieved elimination of onchocerciasis. Colombia was the first country in the world to be verified and declared free of onchocerciasis by WHO. This has been followed by Ecuador in September 2014, Mexico in July 2015, and Guatemala in July 2016. More than 500 000 people no longer need ivermectin in the Americas.
WHO recommends treating onchocerciasis with ivermectin at least once yearly for 10 to 15 years. Where O. volvulus co-exists with Loa loa, treatment strategies may need to be adjusted. Loa loa is a parasitic filarial worm that is endemic in Angola, Equatorial Guinea, Gabon, Cameroon, the Central African Republic, the Republic of Congo, the Democratic Republic of the Congo, Nigeria , Tchad and South Sudan.Treatment of individuals with high levels of L. loa in the blood can sometimes result in severe adverse events. Affected countries, should follow the Mectizan Expert Committee (MEC)/APOC recommendations for the prevention and management of severe adverse events.
WHO provides administrative, technical and operational research support to three regions where onchocerciasis is transmitted.
The Onchocerciasis Technical Advisory Subgroup (OTS) setup by WHO in 2017is providing guidance and oversight for operational research to identify endemic areas that require MDA. In areas co-endemic for lymphatic filariasis, research efforts are focused on developing strategies for co-evaluation of onchocerciasis and lymphatic filariasis, in order to support proper decision making regarding the stopping of MDA.
Diagnosis of onchocerciasis remains a challenge for programmes. The NTD Diagnostics Technical Advisory Group identified development of new diagnostic tools for onchocerciasis as a specific priority. A subgroup was convened to prepare 2 target product profiles (TPPs) for new diagnostics for mapping onchocerciasis and for a confirmatory test for deciding to stop MDA. The TPPs have now been posted on the WHO website.
The WHO Regional Office for Africa, which had an overall supervisory role for OCP from 1975 to 2002 and APOC from 1995 to 2015, currently supervises ESPEN which coordinates control and elimination strategiesin that region.
Through the OEPA partnership, WHO collaborates with endemic countries and international partners in the WHO Region of the Americas. Although there is no official programme to coordinate activities in the WHO Eastern Mediterranean Region, the two countries in the region collaborate on elimination activitiesand receive the support of ESPEN to achieve elimination of river blindness.
With the shift from control to elimination, large areas in Africa require mapping to assess whether transmission is active and treatment required. A sampling strategy name Onchocerciasis elimination mapping has been developed to help countries conduct those assessments and start treatment where needed.
To achieve elimination goals for onchocerciasis, an ambitious research agenda will be needed to support programme progress. Specific research needs include:
Go here to read the rest:
Onchocerciasis - World Health Organization (WHO)
- WHO launches first World report on vision - October 22nd, 2024
- Eye health, vision impairment and blindness - World Health Organization ... - October 22nd, 2024
- Eye care, vision impairment and blindness: Refractive errors - October 22nd, 2024
- Blindness Prevention and Control - World Health Organization (WHO) - October 22nd, 2024
- Onchocerciasis (river blindness) - World Health Organization (WHO) - October 22nd, 2024
- Trachoma - World Health Organization (WHO) - October 22nd, 2024
- Blindness is not a curse to be broken - America: The Jesuit Review - October 22nd, 2024
- Alfred University gives away two pairs of EnChroma glasses for color blindness - www.alfred.edu - October 22nd, 2024
- All the Plants We Cannot See - The Revelator - October 22nd, 2024
- ASI Power Summit 2024: How Blindness Helped Michael Hingson Survive the 9/11 Attacks - ASI - October 22nd, 2024
- People with blindness and their allies rally outside Uber and Lyft over ride denials - The Mercury News - October 22nd, 2024
- New Study Links Ozempic to BlindnessBut They Can Actually Protect Your Eyes - First For Women - October 22nd, 2024
- Conservatives Use Trump Assassination Attempt to Target Women in Anti-Diversity War - The American Prospect - October 22nd, 2024
- Google AI to help detect preventable blindness in India and Thailand - Techloy - October 22nd, 2024
- How blindness drove man to seek, spread solutions - The Star Kenya - October 22nd, 2024
- As Glaucoma Rates Soar, Heres What to Know About This Progressive Condition - News Reports - October 22nd, 2024
- Heres how you can spot and prevent cataracts from causing blindness - SNL24 - October 22nd, 2024
- What Are the 7 Causes of Blindness? - Healthline - June 2nd, 2024
- Blindness and Low Vision | American Foundation for the Blind - June 2nd, 2024
- Eye care, vision impairment and blindness - World Health Organization (WHO) - October 27th, 2023
- CHOROIDEREMIA RESEARCH FOUNDATION EXPANDS RESEARCH SUPPORT INTO NONSENSE MUTATIONS OF A RARE INHERITED RETINAL - EIN News - May 1st, 2023
- Chennai eye hospital ties up with Iceland firm to adopt mathematical algorithm to predict diabetic retinopathy - The Hindu - April 23rd, 2023
- Drug-Resistant Bacteria Tied to Eyedrops Can Spread Person to Person ... - April 7th, 2023
- Prevention of Blindness Week 2023: Mumbai experts explain why you should be concerned about glaucoma and the need for regular eye checkups -... - April 7th, 2023
- Childhood blindness - Wikipedia - February 24th, 2023
- FDA Approves Syfovre (pegcetacoplan injection) for the Treatment of ... - February 24th, 2023
- Human mini brains illuminate path to curing blindness - February 16th, 2023
- Raymond V. Gilmartin: Man with a global vision - February 16th, 2023
- Why Are People So Mad About MrBeast's Blindness Video? - February 16th, 2023
- This heartwarming video of a colorblind boy seeing color for the first time will make you cry - Indiatimes.com - February 16th, 2023
- Blindness (Vision Impairment): Types, Causes and Treatment - February 8th, 2023
- CDC urges people to stop using brand of artificial tears linked to ... - February 8th, 2023
- Health News Roundup: U.S. FDA says India-made eye drop linked to some infections, blindness and one death; China records 3,278 COVID-related deaths... - February 8th, 2023
- I had two strokes at 29 and gone blind -I've been accused of faking my sight loss - Daily Mail - February 8th, 2023
- Blindness and vision impairment - World Health Organization - January 23rd, 2023
- Recovery from blindness - Wikipedia - January 23rd, 2023
- Colour blindness tests, juggling, avoiding glare: A hockey goalkeepeers quest to train his biggest weapon, eyes - The Indian Express - January 23rd, 2023
- But Did You See the Gorilla? The Problem With Inattentional Blindness ... - October 15th, 2022
- Canadians unaware of diseases that lead to blindness, survey says - CTV News Northern Ontario - October 15th, 2022
- A Review of Corneal Blindness: Causes and Management - Cureus - October 15th, 2022
- A cure for blindness may be first product made in space - Freethink - October 15th, 2022
- Is MrBeast trying to cure 1000 people's blindness? - indy100 - October 15th, 2022
- Early detection and management is the key to prevent glaucoma related blindness: Experts - Express Healthcare - October 15th, 2022
- As World Sight Day Nears, River Blindness is Fading - SaportaReport - October 15th, 2022
- Tears of happiness: How curing blindness in Dolakha saved a girls future - City A.M. - October 15th, 2022
- World Sight Day: Orbis, UC Davis team up to train eye care teams from Latin America to fight avoidable blindness - Ophthalmology Times - October 15th, 2022
- Juan Williams: The GOPs epidemic of intentional blindness - The Hill - October 15th, 2022
- Charles pays tribute to Malawi's elimination of disease causing blindness - Express & Star - October 15th, 2022
- Coping with calamity: Former NYT columnist Frank Bruni on blindness and vision, at Morristown book fest keynote - Morristown Green - October 15th, 2022
- Sighting solutions in a world of vision for weavers - The New Indian Express - October 15th, 2022
- Blindfold run raises $40,000 for the MUHC Foundation to support glaucoma care at the MUHC - StreetInsider.com - October 15th, 2022
- MacKenzie Scott Donates $15M to Address the Eyecare Needs of the Impoverished - InvisionMag - October 15th, 2022
- Astellas and MBC BioLabs Announce Astellas Future Innovator Prize to Help Biotech Start-ups Accelerate Early Drug Discovery and Research Efforts -... - September 20th, 2022
- Treating cataracts before 'critical age' imperative FBC News - FBC News - September 20th, 2022
- GenSight Biologics to Present at Upcoming Industry and Investor Conferences - Business Wire - September 20th, 2022
- Ashton Kutcher battled vasculitis causing blindness, loss of hearing. Know all about the rare condition - India TV News - August 11th, 2022
- Prevent Blindness Is Recognized as a Healthy People 2030 Champion for Supporting the Initiative's Vision - Vision Monday - August 11th, 2022
- Researchers make progress toward a stem cellbased therapy for blindness - Ophthalmology Times - August 11th, 2022
- The strategic blindness of Israel's caretaker government - JNS.org - August 11th, 2022
- UND professor carries the torch for UND studies of visual impairment and blindness - Grand Forks Herald - August 11th, 2022
- Karan Nagrani is using social media to raise awareness about the 'spectrum of blindness' - ABC News - August 11th, 2022
- Vision impairment and blindness related to NCDs: Fong - FBC News - August 11th, 2022
- Strategic blindness of caretaker government - The Jewish Star - August 11th, 2022
- Massachusetts woman blinded by attack working to help others regain sight - WCVB Boston - August 11th, 2022
- Persuasion Film Review: Is Heterogeneous Casting Race-Inclusionary Or Escapist? - Feminism In India - August 11th, 2022
- Is It Time To Start Using Race And Gender To Combat Bias In Lending? - Forbes - August 11th, 2022
- The journey of Kali Yugi started with the mistake of objectives! - Youthistaan - August 11th, 2022
- A 50-State Review of Access to State Medicaid Program Information for People with Limited English Proficiency and/or Disabilities Ahead of the PHE... - August 11th, 2022
- iHealthScreen Completed Prospective Trial of AI-Based Tool for Age-Related Macular Degeneration (AMD) Screening and Submitting the Results to FDA for... - August 11th, 2022
- Vitamin B12: Why You Need It & Foods To Increase Your Vitamin B12 Intake - NDTV - August 11th, 2022
- Jack Levine: Remembering a dad who proved that even in blindness, there can be vision - The Florida Times-Union - June 26th, 2022
- Potion of Blindness | Minecraft Ideas Wiki | Fandom - June 26th, 2022
- Tightening a molecular "zipper" could help prevent hereditary blindness - New Atlas - June 26th, 2022
- What's the Link Between Glaucoma and Dry Eyes? - Healthline - June 26th, 2022
- Lisa Durden's upcoming documentary "Blind Divas" follows Krystle Allen and Naquela Wright-Prevoe, two Black women entrepreneurs, determined... - June 26th, 2022
- Trump election lies may fit legal concept of willful blindness - Chicago Tribune - June 26th, 2022
- Sightsavers relaunches its thematic strategy The Sun Nigeria - Daily Sun - June 26th, 2022
- Trachoma elimination: millions more to benefit from donated azithromycin - World Health Organization - June 26th, 2022
- Dangers of super gonorrhoea from infertility to blindness as global warning issued - Daily Star - June 26th, 2022
- Fifty years of Title IX: What is it, what does it cover and do we still need it? - The Athletic - June 26th, 2022
Tags: