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Corneal Disorders
Published in Ching-Yu Cheng, Tien Yin Wong, Ophthalmic Epidemiology, 2022
Darren S. J. Ting, Rashmi Deshmukh, Daniel S. W. Ting, Marcus Ang
Onchocerciasis, also known as “river blindness,” is caused by the filarial worm Onchocerca volvulus, which is transmitted by the bites of blackflies of Simulum spp. After trachoma, it is the second leading cause of corneal blindness in the world.51 Approximately 37 million people are estimated to be infected worldwide, and 300,000 of them are permanently blind.52
Onchocerciasis in the Sierra Parima and Upper Orinoco Regions, Federal Territory of Amazonas, Venezuela *
Published in Max J. Miller, E. J. Love, Parasitic Diseases: Treatment and Control, 2020
Diagnosis of onchocerciasis was also made using an ELISA test as described by Yarzábal et al. 16 The antigen was the same as that used for intradermal tests at a concentration of 40 μg/ml of protein. Sera were tested at a dilution of 1:200. Sera from 30 persons living in areas of Venezuela free from onchocerciasis were used as controls. A positive reaction was considered as that having an optical density greater than the mean plus 2 SD of the control values.
Infectious and parasitic causes of hypopigmentation
Published in Electra Nicolaidou, Clio Dessinioti, Andreas D. Katsambas, Hypopigmentation, 2019
Serena Gianfaldoni, Aleksandra Vojvodic, Nooshin Bagherani, Bruce R. Smoller, Balachandra Ankad, Leon Gilad, Arieh Ingber, Fabrizio Guarneri, Uwe Wollina, Torello Lotti
Onchocerciasis, also known as “river blindness,” is a parasitic disease caused by the filarial nematode Onchocerca volvulus.40,41 Its burden and socioeconomic consequences are significant: estimated loss of 1 million disability-adjusted life-years (healthy life-years lost due to disability and mortality), because of cutaneous manifestations, severe visual impairment (500,000 cases), blindness (270,000 cases), parasite-induced immunosuppression, epilepsy, and social stigmatization, all leading to a decrease of a host's life expectancy, although onchocerciasis is not lethal per se.42
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
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.
Development of a recombinant vaccine against human onchocerciasis
Published in Expert Review of Vaccines, 2021
David Abraham, John Graham-Brown, Darrick Carter, Sean A. Gray, Jessica A. Hess, Benjamin L. Makepeace, Sara Lustigman
Human onchocerciasis (‘river blindness’), caused by the filarial nematode parasite Onchocerca volvulus, is a major cause of infectious blindness, skin disease, and chronic disability. It infects many millions worldwide with 99% of the cases sustained in 31 countries of Sub-Saharan Africa- resulting in widespread vision impairment and blindness. Current estimates put 120 million people at risk [1,2]. The Global Burden of Disease Study estimated in 2017 that there were 20.9 million people infected worldwide, of which 14.6 million had skin disease and 1.15 million had vision loss [3,4] (Figure 1). Importantly, it has become apparent in recent years that onchocerciasis-associated epilepsy (OAE) is also an important public health problem caused by onchocerciasis. In a recent door-to-door survey in Mvolo, an onchocerciasis endemic region in South Sudan, the prevalence of epilepsy in this population was higher (5.1%) than blindness (2.8%) [5].