ONCHOCERCIASIS: THE PUBLIC HEALTH IMPACT IN AFRICA

ONCHOCERCIASIS: THE PUBLIC HEALTH IMPACT IN AFRICA

ENVIRONMENTAL HEALTH (PUBH 8165-1)INSTRUCTOR: DR. SHANA MORRELL

FAITH MBANUGOPHD PUBLIC HEALTHWALDEN UNIVERSITYMAY 02, 2009

ONCHOCERCIASIS: THE PUBLIC HEALTH IMPACT IN AFRICAOnchocerciasis and the public health challenges it presents in African nations has attracted much attention around the world and this presentation will focus on the disease itself, interventions and challenges encountered.1TARGET AUDIENCEEnvironmental Health workersResidents of endemic areasTravelers from the US to endemic areasRepresentatives of WHO and other agencies involved in Onchocerciasis control Health Ministries in Africa

This presentation is intended to educate those who are living and working in areas where this disease is endemic.2Learning objectivesWhat is OnchocerciasisWhat are the symptomsHow is it transmittedHow is it diagnosedWHO control programsChallenges faced

At the end of this presentation the audience will be able to describe the disease Onchocerciasis, its symptoms, how it is diagnosed and treated. This presentation will highlight the two main control programs in Africa as well as the challenges faces in the battle against this disease.3ONCHOCERCIASIS: THE DISEASEENDEMIC IN 28 SUB-SAHARAN AFRICAN NATIONS (WHO, 1995)APPROXIMATELY 42 MILLION PEOPLE WORLDWIDE AFFLICTED (LEVINE,2007)THE DISEASE IS CAUSED BY THE PARASITIC WORM ONCHOCERA VOLVUS TRANSMITTED TO HUMANS BY BLACKFLIES (THYLEFORS &ALLEMAN,2006)

ReferencesLevine,R. (2007). Case Studies in Global Health: Millions Saved. Sudbury, MA: Jones and Bartlett Publishers.Thylefors, B. & Alleman, M. (2006). Towards the elimination of Onchocerciasis. Annals of Tropical Medicine & Parasitology, 100(8), pp. 733-746.WHO (1995). Onchocerciasis and its Control. Report of a WHO Expert Committee. Technical report Series No. 852. Geneva: WHO

Onchocerciasis or River Blindness is also endemic in Yemen and 6 Latin American countries, but this presentation will focus on the impact of this disease in Africa where it is endemic in 28 Sub-Saharan African nations. This disease is found in poor rural and remote parts of Africa, and has devastated the lives of many people in the endemic areas. 42 million people world wide are afflicted with this disease. The black-flies are the main vectors of this disease, transmitting the parasitic worm Onchocera Volvus to humans.4MODE OF TRANSMISSIONThe Vector-THE SIMULIUM BLACKFLY TRANSMITS ONCHOCERCIASIS BY BITING INFECTED PERSON -THE BLACK FLY INGESTS MICROFILARIAE OF O. VOLVUS, THEN BITES ANOTHER PERSON-THE BLACKFLIES BREED IN RIVERINE AREAS AND RESIDENTS IN THIS AREA ARE BITTEN OFTEN (LEVINE, 2007)ReferenceLevine, R. (2007). Case Studies in Global Health: Millions Saved, Sudbury, MA: Jones and Bartlett Publishers.The long-range flight capacity of black-flies (400 kilometers) make it possible for them to invade neighboring countries and spread this disease. Residents in riverine areas where the black-flies breed, are bitten as many as 10,000 times a day. When the black-flies bite an infected person, they ingest the microfilariae of the O. Volvus which gets passed on when another person is bitten.5THE ONCHOCERCIASIS CYCLERetrieved from http://www.cartercenter.org/health/river_blindness/index.html

This picture depicts the disease cycle of onchocerciasis, as it goes through the infection, proliferation, reproduction and transport phases.6Transmission ContinuedThe Victim-INSIDE THEHUMAN BODY O. VOLVUS LARVAE GROWS INTO ADULT WORMS-AFTER MATING THE ADULT FEMALE PRODUCES MILLIONS OF MICROSCOPIC MICROFILARIA-THE MICROFILARIA CONSTANTLY MOVE THROUGH THE SKIN AND EYES CAUSING SYMPTOMS (LEVINE, 2007)

ReferencesLevine, R. (2007). Case Studies in Global Health: Millions Saved. Sudbury, MA: Jones and Bartlett Publishers.

The adult worms can be up to two to three feet in length and the microfilaria can live up to two years inside the human body before they die. The adult female has the capability producing millions of microscopic microfilaria which causes symptoms like itching and impaired vision as they move through the skin and eyes.7THE ONCHOCERA VOLVUS WORMSRetrieved from http://www.studenttravel.about.com/b/2005/08/02/2005-2006-cdc-yellow-book-dastardly-disease-and-evil-animals.htm

This is a picture of the O. Volvus worms as they would be found in clusters inside nodules on the victims skin.8SYMPTOMSSKIN (WHO, 2009)- Rashes-Swelling-Inflammation-Lesions-Intense itching-Nodules on skin

ReferencesWHO (2009). Onchocerciasis the disease and its impact. Retrieved from http://www.who.int/apoc/onchocerciasis/disease/en/index.html

The skin symptoms are caused when microfilariae die in the subcutaneous layers of the skin. The natural defenses in the human body causes nodules to form around mature worms, giving the skin a rough lizard-like look. It is typical to see rashes, swelling., inflammation and intense itching in victims.9ONCHOCERCIASIS NODULESRetrieved from http://www.asnom.org/en/442_onchocerciasis.htm

This picture shows a nodule filled with adult worms on the skin of an infected person.10SYMPTOMS CONTD.EYES (WHO, 2009)-WHEN MICROFILARIAE MIGRATE TO THE EYES AND DIE, IT CAUSES AN INFLAMMATORY RESPONSE WHICH LEADS TO;-IMPAIRED VISION DUE TO KERATITIS-BLINDNESS-SECONDARY GLAUCOMA

ReferenceWHO (2009). Onchocerciasis the disease and its impact. Retrieved from http://www.who.int/apoc/onchocerciasis/disease/en/index.html

In the riverine breeding sites, blindness affected up to 50% of adults in some areas. The optic nerve is involved and leads to loss of visual field.11EYE LESIONS FROM ONCHOCERCIASISRetrieved from http://www.cehjournal.org

These pictures show different stages of impaired vision in patients with Onchocerciasis. When the worms die in the eyes, they cause an inflammatory reaction that ultimately causes blindness. Blindness due to Onchocerciasis is the worlds fourth leading cause of preventable blindness after cataract, glaucoma and trachoma.12DIAGNOSTIC METHODSSkin snipAntigen - based Immunological assayThe Mazzotti testDiethyl Carbamazine Patch testPCR based techniqueSlit lamp examNodule palpation(Thylefors & Alleman, 2006)ReferencesThylefors, B. & Alleman, M. (2006). Towards the elimination of onchocerciasis. Annals of Tropical Medicine & Parasitology, 100(8), pp. 733-746.The classic diagnosis is the detection of micrfilariae in a skin snip, which exposes hundreds of writhing worms. Because of the discomfort caused by snipping the skin the other less invasive methods of diagnosis are being explored. The antigen-based immunological assay, uses a drop of blood from the patients finger to test for the presence of O. volvus antigens. The Mazzotti test involves giving an oral dose of 5 mg of diethyl-carbamazine (DEC) to the patient. If the patient has Onchocerciasis intense itching starts within 2 hours due to dying microfilariae. The DEC patch test involves the local application of 10% DEC anhydrous lanolin to the skin and covered with a dressing. The patch is checked for local dermatitis caused by the dying worms. The PCR based technique uses a machine to amplify parasite DNA sequences in skin snip specimens. This method can be used to diagnose patients with low level infection because of its high sensitivity. The nodule palpation is not a definitive diagnoses. It is a good indication that further tests need to be run to confirm diagnosis. The slit lamp exam involves using a microscope with a light to for floating worms inside the eyes.13SKIN SNIPRetrieved from http://www.stanford.edu/class/humbio103/ParaSites2006/Onchocerciasis/Diagnosis.html

This picture demonstrates how the skin snip is done. The skin is prepared with an antiseptic and then a fold is squeezed between the physicians' thumb and forefinger. A tiny slice of skin is then removed.14Combating OnchocerciasisEARLY CONTROL EFFORTS-DRUGS USED INCLUDED SURAMIN AND DIETHYLCARBAMAZINE CITRATE (Thylefors & Alleman, 2006)

-NODULECTOMY

-VECTOR CONTROL THROUGH SPRAYING BREEDING SITES WITH DDT (Levine, 2007)

ReferencesLevine, R. (2007). Case Studies in Global Health: Millions Saved. Sudbury, MA: Jones and Bartlett Publishers.Thylefors, B. & Alleman, M. (2006). Towards the elimination of onchocerciasis. Annals of Tropical Medicine & Parasitology, 100(8), pp. 733-746.

Suramin had severe kidney and skin complications, and Diethylcarbamazine citrate caused severe allergic and immunological reactions which made the eye lesions worse. Nodulectomy was difficult to apply as a public health intervention. Insecticides were ineffective because the black-flies could fly very long distances to other locations. Because these early control efforts were not very successful, there was need to explore other control programs.15THE ONCHOCERCIASIS CONTROL PROGRAM (OCP)- 1974 to 2002-LAUNCHED IN 1974 UNDER WHO -PARTNERS INCLUDED WORLD BANK, FOOD AND AGRICULTURE ORGANIZATION, THE UNITED NATIONS DEVELOPMENT FUND (WHO, 2009)-COVERED 11 AFRICAN COUNTRIES (WHO, 2009)-INITIAL STRATEGY WAS VECTOR CONTROL-TREATMENT WITH IVERMECTIN ADDED 1988 (WHO)ReferenceWHO (2009). Onchocerciasis Control Programme (OCP). Retrieved from http://www.who.int/blindness/partnerships/onchocerciasis_OCP/en/

The 7 countries covered by OCP are Benin, Burkina Faso, Cote dIvoire, Ghana, Guinea Bissau, Guinea, Mali, Niger, Senegal, Sierra Leone, and Togo. Initially the strategy used by the OCP was vector control through spraying of the breeding sites with insecticides. In 1988 treatment with Ivermectin was added. Ivermectin (Mectizan) was manufactured and donated by Merck & Co., Inc. for as long as it is needed. Ivermectin kills the microfilariae that live in the subcutaneous tissue of the infected person slowly, and suppresses the production of microfilariae by adult female worms for a few months after treatment. According to the WHO the effective dosage is 150 to 200 micrograms/kg body weight.16

This map shows the 11 countries covered by OCP as shown by the WHO. These countries are Benin, Burkina Faso, Cote dIvoire, Ghana, Guinea Bissau, Guinea, Mali, Niger, Senegal, Sierra Leone, and Togo.17

This a picture of the container of Ivermectin donated by Merck & Co., Inc. who has pledged to donate the drug for as long as it is needed.18The African Program for Onchocerciasis Control (APOC)-ESTABLISHED IN 1995-INCLUDES 19 PARTICIPATING AFRICAN COUNTRIES-PARTNERS WITH HEALTH MINISTERIES, NON-GOVERNMENTAL DEVELOPMENT ORGANIZATIONS-UTILIZES COMMUNITY DIRECTED TREATMENT WITH IVERMECTINE (CDTI) (WHO, 2009)ReferenceWHO (2009). African Programme for Onchocerciasis Control (APOC). Retrieved from http://www.who.int/blindness/partnerships/APOC/en/

APOC is bigger than OCP and includes the following countries: Angola, Burundi, Cameroon, Central African Republic, Chad, Congo, Democratic Republic of Congo, Ethiopia, Equatorial Guinea, Gabon, Kenya, Liberia, Malawi, Mozambique, Nigeria, Rwanda, Sudan, Tanzania and Uganda. This program empowers local communities to fight river blindness in their own villages. This program is expected to treat 90 million people annually. The main differences between the OCP and APOC is that the APOC program established effective self-sustaining, annual and community-based treatments with Ivermectin. So the members of the community were empowered to help control this disease in their different communities. OCP pretty much had the WHO and the foreign agencies conduct these control programs without the community being empowered like in the APOC program.19

This map shows the 19 countries included in the APOC program.20IMPACT OF INTERVENTIONS

CDTI ACHIEVED ESTIMATED TREATMENT COVERAGE RATE OF 74%-80% REDUCTION IN OPTIC NERVE DISEASE-50% REDUCTION IN ITCHING (Levine, 2007)ECONOMIC BENEFITS AS PEOPLE RETURNED TO FERTILE LANDS TO FARM (Hodgkin et al., 2007)

ReferenceHodgkin, C., Molyneuux, D. H., Abiose, A., Phillipon, B., Reich, M. R., Remme, J. H., Thylefors, B., Traore, M. & Grepin, K. (2007). The future of Onchocerciasis control in Africa. PLoS Neglected Tropical Diseases, 1(1).

Because of the success of the APOC programme and the fear that if it is stopped prematurely the gains made in controlling this disease will be lost, the APOC programme was extended to 2015. There was marked decrease in the optic nerve disease, and a 50% reduction in itching. The community directed treatment initiative achieved a treatment coverage rate of 74% which exceeds the minimum coverage of 65% needed to interrupt the transmission of the disease. Economic gains were made as result of the success of these programs. Some of the fertile lands that were abandoned as people tried to escape from onchocerciasis, were being utilized after the disease transmission was halted in these areas. This led to increase in crop diversity, bountiful agricultural harvests and improved human nutrition.21IMPACT Contd.-OTHER INCIDENTAL BENEFITS FROM IVERMECTINE TREATMENT INCLUDE EXPULSION OF INTESTINAL WORMS, REVERSASL OF SECONDARY AMENNORRHEA, IMPROVED LIBIDO IN MEN, CLEARANCE OF HEAD LICE (Anosike et al., 2007)ReferenceAnosike, J. C., Dozie, I. N. S., Ameh, G. I., Ukaga, C. N., Nwoke, B. E. B., Nzechukwu, C. T., Udujih, O. S. & Nwosu, D. C. (2007). The varied beneficial effects of ivermectin (Mectizan) treatment, as observed within onchocerciasis foci in south-eastern Nigeria. Annals of tropical Medicine & Parasitology, 101(7), pp. 593-600.

There were a lot of other incidental benefits from Ivermectin treatment like expulsion of intestinal worms, reversal of secondary amenorrhea, increased appetite, improved libido in men and clearance of head lice. All the noted beneficial effects of the Ivermectin treatment help motivate the people in endemic areas to continue with the treatment.22CHALLENGES-120 MILLION PEOPLE STILL FACE THREAT OF RIVER BLINDNESS IN AFRICA (WHO, 2007).-CONFLICTS IN AFRICA INHIBIT PROGRAM-LONG RANGE FLIGHT OF BLACK-FLIES POSES RISK OF RE-INTRODUCTION OF DISEASE TO DISEASE FREE AREAS-INSUFFICIENT AFRICAN HEALTH WORKERS AND FACILITIESDespite the successes of both the OCP and APOC programs in Africa, there are still some challenges and potential obstacles to completely eliminating Onchocerciasis. There are still 120 million people still facing the threat of river blindness in Africa, so the battle is far fro being won completely. The conflicts in some APOC and ex-OCP countries inhibits the success of the control programs. Moreover the frequent social and political upheavals in Africa increases the risk of transmission or re-emergence of Onchocerciasis. Because the blackflies have the ability to fly very long distances, there is always a chance that infected flies from countries with weak control, will re-introduce the disease into neighboring countries. There are not enough African health workers and facilities to maintain the gains made in control. This is a major problem because the APOC program is community directed using local manpower.23CHALLENGES Contd.-CONCERNS THAT FINANCING MIGHT DRY UPDETERMINATION OF WHEN TO STOP THE IVERMECTIN TREATMENT SAFELYREFUSAL OF SOME PEOPLE IN ENDEMIC AREAS TO TAKE IVERMECTIN (Semiyaga et al., 2005)ReferenceSemiyaga, N. B., Lalobo, O. & Ndyomugyenyi, R. (2005). Refusal to take Ivermectin: the associated risk factors in Hoima district, Uganda. Annals of Tropical Medicine & Parasitology, 99(2), pp. 165-172. A lot of agencies including the World Bank have helped finance the control programs, and there is a concern that finances will dry up when these agencies pull out. A lot of research is still needed to determine when the Ivermectin treatment could be stopped safely. This is because the adult female worm is not killed by this medication, rather it stops it from reproducing for a couple of months after the treatment. So this treatment needs to continue until the adult worms die naturally in the human body. Because of these challenges it is imperative that the WHO, its partners and the involved countries sustain the control efforts until such a time that eradication of this disease is achieved. There is also the problem of people who for whatever reasons, have decided not to take the medication. These people could act as reservoirs and re-infect others in the community.24RECOMMENDATIONSTHE AFRICAN NATIONS, THE WHO AND THEIR PARTNERS SHOULD SUPPORT RESEARCH EFFORTS TO DETERMINE WHEN IVERMECTIN TREATMENT CAN BE STOPPED SAFELYAFRICAN NATIONS SHOULD GIVE PRIORITY TO FUNDING OF ONCHOCERCIASIS CONTROL PROGRAMS IN THE NATIONAL BUDGET

It is necessary for the African nations, WHO and their partners to support research efforts to determine when the Ivermectin treatment can be stopped safely. There is also need for research into alternative medications that can kill the adult worm also. African nations should give priority in their budget to funding of the Onchocerciasis control program. They need to take ownership of this problem instead of relying on outside agencies and countries to help finance this.25RECOMMENDATIONS Contd.-INTEGRATE CONTROL PROGRAMS INTO THE HEALTH SYSTEM-INTENSIFY CONTROL ACTIVITIES IN POST-CONFLICT COUNTRIES-GRASSROOT EDUCATIONAL PROGRAMS TO EXPLAIN THE GOAL OF TREATMENT WITH IVERMECTIN-CONTINUE SURVEILLANCE AND TREATMENTThere is need to integrate control programs into the health system, making treatment options readily available to those at risk. Control programs should be intensified in the post-conflict countries to ensure that they do not serve a source of infected flies and persons. Since some people refuse treatment, it obvious that they do not fully understand what the benefits of the control program are. A grassroots educational program will help explain the goals and benefits of the control programs. Surveillance activities need to continue in endemic areas, so that any outbreak of the disease can be treated before it gets to epidemic proportions and put more people at risk of contracting the disease.26QUESTIONS ???Thank you for your attention. I have this presentation has helped you understand how Onchocerciasis is transmitted, diagnosed and treated. Hopefully you can utilize this information in your various localities to help with the efforts towards eradication of this disease. I will be glad to answer any questions you have at this point. Questions please.27ReferencesAnosike, J. C., Dozie, I. N. S., Ameh, G. I., Ukaga, C. N., Nwoke, B. E. B., Nzechukwu, C. T., Udujih, O. S. & Nwosu, D. C. (2007). The varied beneficial effects of ivermectin (Mectizan) treatment, as observed within onchocerciasis foci in south-eastern Nigeria. Annals of Tropical Medicine & Parasitology, 101(7), pp. 593-600.Hodgkin, C., Molyneux, D. H., Abiose, A., Philippon, B., Reich, M. R., Remme, H. J., Thylefors, B., Traore, M. & Grepin, K. (2007). The future of onchocerciasis control in Africa. PLoS Neglected Tropical Diseases, 1(1).The following are the references utilized for putting this presentation together. Thanks again for your attention.28Semiyaga, N. B., Lalobo, O. & Ndyomugyenyi, R. (2005). Refusal to take Ivermectin: the associated risk factors in Hoima district, Uganda. Annals of Tropical Medicine & Parasitology, 99(2), pp. 165-172.Thylefors, B. & Alleman, M. (2006). Towards the elimination of onchocerciasis. Annals of Tropical Medicine & Parasitology, 100(8), pp. 733-746.WHO (2009). African Programme for Onchocerciasis Control (APOC). Retrieved from, http://www.who.int/blindness/partnerships/APOC/en/

29WHO (2009). Onchocerciasis Control Programme (OCP). Retrieved from, http://www.who.int/blindness/partnerships/onchocerciasis_OCP/en/WHO (2009). Onchocerciasis the disease and its impact. Retrieved from, http://www.who.int/apoc/onchocerciasis/disease/en/index.htmlWHO (2007). Onchocerciasis control in the WHO African region: Current situation and a way forward. Report of Regional Committee for Africa. 57th session, Brazzaville, Congo.30