Suramin
M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson in Kucers’ The Use of Antibiotics, 2017
Onchocerciasis is a chronic parasitic infection caused by the filarial nematode Onchocerca volvulus. Larval forms are transmitted by the bite of an infected black fly of the Simulium genus (WHO, 1995; Simonsen, 2009). The term “river blindness” is used because the habitat for black fly breeding is in areas near fast-flowing streams and rivers. The disease is endemic across large parts of Africa and Yemen. Over 6–12 months, the larvae develop into adult worms that live in deep subcutaneous or intramuscular layers (Murdoch, 2016). The adult female produces microfilariae which migrate through subcutaneous tissues causing the clinical manifestations of onchocerciasis, including skin nodules, pruritic dermatitis, and the most devastating symptoms of ocular onchocerciasis. Each female can produce 1000–3000 offspring per day over a lifetime, which can be up to 15 years (Murdoch, 2016). Infection results in skin disease (onchodermatitis) and eye disease (affecting both the anterior and posterior segments of the eye).
Infectious and parasitic causes of hypopigmentation
Electra Nicolaidou, Clio Dessinioti, Andreas D. Katsambas in Hypopigmentation, 2019
Early signs of infection include fever, neuralgic pain in joints, and temporary hives on trunk and face. Onchocerciasis is initially characterized by itch, often intense and widespread. This is followed, in 3–36 months, by erythematous exanthema, with numerous small (1–3 mm), round papular elements, sometimes with superficial and/or apical desquamation (acute papular onchodermatitis). Evolution is to chronic papular onchodermatitis and lichenified onchodermatitis, with possible hypertrophic, verrucous, and/or eczema-like aspects, xerosis, and hyperpigmentation. Late skin lesions include hypo-/atrophy, hypo-/depigmentation (“leopard skin”), and onchocercomas (fibrous, mobile, asymptomatic nodules, located at bony prominences in areas of Simulidae bites and containing adult nematodes).40,41,43
Flies (Biting)
Gail Miriam Moraru, Jerome Goddard in The Goddard Guide to Arthropods of Medical Importance, Seventh Edition, 2019
Black flies (also called buffalo gnats, turkey gnats, and Kolumbtz flies) are small, humpbacked flies that are important as vectors of disease and as nuisance pests.1,2 In the tropics, black flies are vectors of the parasite Onchocerca volvulus, which causes a chronic nonfatal disease with fibrous nodules in subcutaneous tissues and sometimes visual disturbances and blindness (river blindness). The World Health Organization estimates that about 17 million people have onchocerciasis in Africa and Latin America (Figure 19.1).3 Since 1987 (and still ongoing), onchocerciasis control has been greatly aided by mass drug administration of ivermectin, which has been a gold standard antiparasitic drug. More recently, a structurally similar new drug, moxidectin, has shown even more efficacy. There is a goal of total elimination of onchocerciasis from most of Africa by 2025.4 Interestingly, an autoimmune response to infection with Onchocerca filarial worms has been reported, leading to a form of epilepsy and “nodding syndrome” in children in parts of Africa.5
Infectious diseases among Ethiopian immigrants in Israel: a descriptive literature review
Published in Pathogens and Global Health, 2021
Yulia Treister-Goltzman, Ali Alhoashle, Roni Peleg
Onchocerciasis is a systemic disease caused by the filarial parasite Onchocerca volvulus. It is endemic in Africa and South America and transmitted by the Simulium blackfly. Most EI, especially those who arrived in Israel up to 1991, came from Gondar province in western Ethiopia where the prevalence of Onchocerciasis is not very high. The first reports on this disease among EI appeared in the 1990s [67]. A large proportion of EI who arrived after 1992 came from the Kuwara highland in northwest Ethiopia, which is considered a very endemic area where the prevalence of Onchocerciasis reaches 84%. Israeli investigators screened a large group of EI from this endemic area to identify Onchocerciasis [68]. They found a high rate of skin involvement, particularly in the lower extremities. In over 40% of the patients who were suspected of having eye damage based on their complaints, there was corneal pathology including scars, infiltrates, and even microfilariae. The disease caused uveitis, keratitis, and even secondary glaucoma [68,69]. The disease was diagnosed by a skin snip test or serological testing. Prior to that study [68] none of the infected EI received this diagnosis, due to a low level of awareness of the disease by physicians, nonspecific and mild clinical findings, and lack of training in the conduct of the skin snip test. Blindness is one of the most severe results of this disease, so it was very important to raise the level of awareness and knowledge of physicians on Ochocerciasis in EI, especially from the Kuwara region.
Ivermectin: a mini-review
Published in Clinical Toxicology, 2022
Ivermectin is generally well tolerated after therapeutic oral exposure when used for anthelminthic purposes. Commonly adverse effects associated with therapeutic anthelminthic ivermectin ingestion include headache, nausea, pain, edema, skin rashes, and dizziness [20]. Pain, swelling, and cutaneous reactions are often reported in patients treated with single-dose therapy for treatment of onchocerciasis, but these side effects may be more closely related to the primary disease process than the treatment provided. In a pharmacokinetic study, healthy adult volunteers tolerated up to 2000 mg/kg of ivermectin without serious toxicity [7]. In this study, transient and mild adverse events (including headache, nausea, dizziness, and rash) occurred at similar frequencies in subjects who received placebo or ivermectin. The incidence of adverse events was not dose-dependent. In school-aged pediatric patients, ivermectin has been tolerated at doses up to 600 mcg/kg [21]. In this population, most adverse events, including headache, abdominal pain, photophobia, and pruritus, were mild and resolved within 48 h of drug administration.
WHO Vision 2020: Have We Done It?
Published in Ophthalmic Epidemiology, 2023
Dalia Abdulhussein, Mina Abdul Hussein
Certain factors have limited the success of eradicating onchocerciasis. Firstly, although Ivermectin slows the spread of onchocerciasis, it does not eradicate the disease.26 WHO recommends treating onchocerciasis with ivermectin at least once yearly for 10–15 years.25 The parasite can survive for up to 15-years, therefore there needs to be a long-term treatment that can be sustained by the communities themselves as.26 One way in which this can be achieved is by using a milbemycin endectocide such as Moxidectin.26 Research has shown lower parasite transmission after treatment with Moxidectin compared to Ivermectin.27 This may be because Moxidectin can kill the adult worms responsible for the disease. Furthermore, there is incomplete mapping of all transmission zones and suboptimal program implementation.28
Related Knowledge Centers
- Biopsy
- Onchocerca Volvulus
- Trachoma
- Visual Impairment
- Parasitic Worm
- Black Fly
- Simulium
- Saline
- Vaccine
- Insect Repellent