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Summary - Sowda

The text is the summary of recent articles on Sowda from National Library of Medicine (NLM). This information is subject to NCBI's Disclaimer and Copyright notice.

The onchocerciasis focus in Yemen has been known for many years as an endemic area with unique characteristics, notably the atypical and most severe form of onchodermatitis, known as sowda or reactive onchodermatitis (ROD). Onchocerciasis is a neglected parasitic disease affecting the poorest underserved people in Yemen. Clinical manifestations in onchocerciasis range from generalized onchocerciasis (GEO) to the rare but severe hyperreactive (HO)/sowda form. Th2-biased inflammation with eosinophilia and IgE production is a hallmark of helminth infections. Ectopic secondary lymph follicles emerge in patients with autoimmune or infectious diseases, e.g. in the synovium in rheumatoid arthritis or the skin in Borrelia burgdorferi infection, but ectopic localisations in the skin are rarely described for helminth infections. During one academic year, three patients were referred to Parasitology Laboratory from Dermatology Outpatients Clinics in King Abdulaziz University Hospitals. The geophysics of the north Yemen, associating a north-south directed mountainous fish bone (rising in more of 2,000 meters), to numerous rivers or "wadis" is convenient to the development of simulium shelters, main vectors for cutaneous filariasis to Onchocerca sp. Onchocerca volvulus infection usually results in a predominantly immunopermissive reaction called generalized onchocerciasis and characterized by high microfilarial burden and immunological tolerance to the worms. The mechanism by which the minority of patients with onchocerciasis exhibiting the hyperreactive (sowda) form of the disease may be able to kill the microfilariae of Onchocerca volvulus is still poorly understood. The protein Ov20/OvS1 was used as antigen in ELISA and Western blot in order to differentiate onchocerciasis from African mansonelliasis and to characterize the hyperreactive form of Onchocerca volvulus infection (sowda). Eosinophils, eosinophil cationic protein (ECP), eosinophil-derived neurotoxin (EDN/EPX), myeloperoxidase (MPO) and IgE were measured in blood, serum and/or urine in Schistosoma haematobium- and Onchocerca volvulus-infected Guineans and O. volvulus- and S. haematobium-negative Guineans coinfected or infected with intestinal nematodes. Onchocerciasis has been reported in Sudan since 1908 and now prevails in three endemic regions known as the southern, northern and eastern foci. In onchocerciasis, variations of the host's immune responsiveness produce a spectrum of clinical manifestations ranging from the common generalized to the rare hyperreactive form (sowda). Sowda skin lesions are of medical and social importance in Yemen. Onchocerciasis is a major blinding disease in equatorial Africa and Central and South America. The excretory-secretory (E-S) products of helminths are considered to comprise immunogenic molecules of high diagnostic value. The serum levels of three major granulocyte proteins were measured in patients with onchocerciasis, bancroftian filariasis and intestinal schistosomiasis and compared to controls from patients with malaria, Africans living in areas not endemic for these infections and healthy Germans. An Onchocerca volvulus expression library was differentially screened to identify a molecular marker distinguishing sowda (lichenified onchodermatitis) from other onchocerciasis forms. Seventeen male and 39 female Liberian patients, one third of them children, were diagnosed as having hyperreactive onchodermatitis (sowda). Extravasation of host's leukocytes from blood vessels into inflammatory tissues represents a prerequisite for a subsequent interaction with invaded parasites.

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