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The Parasite's Way of Life
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2023
Eric S. Loker, Bruce V. Hofkin
Onchocerca lupi is an emerging parasite of veterinary importance. Like the related O. volvulus, it can result in vision loss for the definitive host. Whereas O. volvulus is a human parasite, O. lupi appears to affect mainly dogs and other canines. The vectors of this parasite have been identified as various species of black fly (genus Simulium) but the exact species in most areas have yet to be determined. Suppose that you wished to identify potential vectors in a particular geographic area and found that a species of black fly was at least occasionally infected with larval stages of O. lupi. What would be your next step, if you wished to further investigate the role of this fly as a potential O. lupi vector?
Black Flies
Published in Jerome Goddard, Public Health Entomology, 2022
Fortunately, black flies are daytime biters and rarely venture indoors; therefore, people can limit outdoor activity during peak black fly emergences. Providing shelters for backyard poultry may help protect them, since the flies do not like to enter enclosures. Repellents containing DEET have been reported effective for humans (but may need to be reapplied frequently), and wearing light-colored clothing may help keep the gnats away. Chemical control of black flies involves application of insecticides for both adults and larvae. This has only limited success, since it is often difficult to locate and treat all breeding sites. Larviciding with the “biological” control agent, Bacillus thuringiensis israeliensis, or BTI, (a spore-forming bacteria that kills the feeding larvae) has shown success in parts of the United States9 and many African countries participating in the Onchocerciasis Control Program (OCP).
Pemphigus
Published in Lionel Fry, Atlas of Bullous Diseases, 2020
In endemic Brazilian pemphigus it has been found that the disorder is more common in rural areas and at the end of the rainy season when insects are most abundant. Bites from the insect ‘black fly’ are a risk factor for the disease, and it is possible that the ‘bite’ contains substances which are antigenic, or that the fly transmits an infectious agent which acts as a trigger.
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.
Epidemiology of major chronic inflammatory immune-related skin diseases in 2019
Published in Expert Review of Clinical Immunology, 2020
Autoimmune blistering disorders, mainly including pemphigus and pemphigoids, are much rarer conditions even if extremely high incidence rates may be found in some foci across the world, e.g. subtropical areas of Brazil [84]. Limited data exist concerning risk factors. An inverse association exists between PV and smoking [96], while fogo selvagem in Brazil has been associated with black fly infestation. Pemphigus has been associated with several autoimmune comorbidities including psoriasis [106]. BP is a rare disease more frequent in elderly people and with higher incidence rates in wealthier countries. A trend for increasing incidence rates of BP over the past few decades has been documented [102], paralleling the improved life expectancy in the countries involved, and the concomitant increased incidence of dementia and other disabling neurological disorders recognized as major risk factors for BP among elderly patients. Also the use of certain drugs, such as diuretics and neuroleptics, reported as risk factors for BP, and an increased awareness of BP from the referring physicians, may play some role in the trend. In spite of the obvious differences we have pointed to, ISDs have in common an increased risk for accelerated atherosclerosis and cardiovascular acute events, possibly linked with systemic inflammation. A major emerging problem is air pollution and global climatic changes. Little is known about the impact of these changes on skin diseases including ISDs.
Moxidectin: an oral treatment for human onchocerciasis
Published in Expert Review of Anti-infective Therapy, 2020
Philip Milton, Jonathan I. D. Hamley, Martin Walker, María-Gloria Basáñez
Some communities have received many years of CDTI but have made somewhat limited progress toward elimination [74–76]. This may be due to low levels of therapeutic coverage (proportion of the total population taking the drug on a given treatment round) and/or high levels of systematic non-adherence (proportion of the population never taking treatment) due to programmatic constraints [77], with untreated (or infrequently treated) individuals maintaining microfilarial loads that contribute to transmission. This situation has been documented in a number of communities across Africa [78–81]. In others, however, although acceptable coverage and adherence may be reached and sustained, very high rates of transmission (due to high blackfly biting rates and/or intense exposure to blackfly bites) can result in substantial inter-treatment transmission even if microfilarial loads are low. Despite the initial rapid microfilaridermia reduction that follows ivermectin, adult female worms gradually resume microfilarial production 3–4 months after treatment [9]. Therefore, as microfilariae repopulate the skin during the period between rounds of aCDTI (or even bCDTI), transmission to vectors can be considerable in communities with high blackfly biting rates. Mathematical modeling studies of onchocerciasis transmission suggest that both high endemicity and unsatisfactory coverage, adherence, and frequency can hinder elimination [82,83]. Moxidectin, delivered through community-directed treatment approaches, could replace ivermectin in areas of persistent transmission, but it would also necessitate reaching and sustaining high levels of therapeutic coverage and adherence. Its superior efficacy and more prolonged suppression of microfilaridermia levels would help, however, to curtail inter-treatment transmission more effectively than ivermectin. Modeling studies have suggested that annual community-directed treatment with moxidectin (aCDTM) may have a similar epidemiological impact to that of bCDTI and mitigate against the increased cost of biannual distribution [45].