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Africa
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An Overview of Helminthiasis
Published in Venkatesan Jayaprakash, Daniele Castagnolo, Yusuf Özkay, Medicinal Chemistry of Neglected and Tropical Diseases, 2019
Leyla Yurttaș, Betül Kaya Çavușoğlu, Derya Osmaniye, Ulviye Acar Çevik
Schistosomiasis is a disease caused by blood flukes (trematodes) belonging to the genus Schistosoma. First described by Theodor Bilharz in the 19th century, schistosomiasis is one of the most common parasitic infections in humans. S. intercalatum, S. mansoni, S. japonicum, S. haematobium and S. mekongi species are the most common etiologic agents. The World Health Organization (WHO) estimates that more than 200 million people are infected by these parasites, making schistosomiasis the second most destructive parasitic disease after malaria. Schistosomiasis affects a large proportion of children under the age of 14 years. Humans are infected when in contact with schistosoma-infested water. Infection is developed when the cercariae, the larval form of the parasite, penetrates the skin during contact with fresh water while bathing, wading or doing laundry. Eggs, larvae, or antigen-antibody immunecomplex deposits of the Schistosoma spp. can settle in any organ or body tissue, including the eyes. The symptoms of human schistosomiasis are mainly due to immune reaction against the invading and migrating larvae and later against the parasite eggs present in the host tissue (Leutscher and Magnussen 2017, Orefice et al. 2016, Kim et al. 2016, Linquist and Cross 2017).
Schistosoma spp.
Published in Peter M. Lydyard, Michael F. Cole, John Holton, William L. Irving, Nino Porakishvili, Pradhib Venkatesan, Katherine N. Ward, Case Studies in Infectious Disease, 2010
Peter M. Lydyard, Michael F. Cole, John Holton, William L. Irving, Nino Porakishvili, Pradhib Venkatesan, Katherine N. Ward
Clinical features may occur at different stages of infection. When cercariae first penetrate the skin there can be local irritation, which may appear immediately or within a few days. Raised, red spots may last a few days. Similarly, a swimmers’ itch can be caused by trematodes of animal origin, particularly in temperate climatic zones.
Infections
Published in C. Simon Herrington, Muir's Textbook of Pathology, 2020
After infection, there may be a local dermatitis where the cercariae penetrated the skin. Once the worms start laying eggs, some people infected for the first time develop an acute systemic disease (Katayama's syndrome) (Box 20.20).
Modeling the transmission phenomena of water-borne disease with non-singular and non-local kernel
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
Wejdan Deebani, Rashid Jan, Zahir Shah, Narcisa Vrinceanu, Mihaela Racheriu
It is well-known that schistosomiasis is a parasite illness transmitted by water that affects people as well as other animals including dogs, sheep, buffaloes, cattle and pigs (Kabatereine et al. 2014). It is a zoonotic illness spread by the dioecious schistosoma intravascular resident fluke (Gao et al. 2014; Walz et al. 2015); furthermore, it is a parasitic trematodiasis produced by schistosoma species, among which S. intercalatum and S. mekongi are of local concern while S. haematobium, S. japonicum and S. mansoni are of worldwide public health significance (Ismail et al. 2014). We focus on schistosoma haematobium which is the common schistosoma species in Sub-Saharan Africa and has been related to increased HIV prevalence and cancer development. It is known that urogenital schistosomiasis is caused by S. haematobium and is transmitted by Bulinus snails (Liu et al. 2011). By coming into touch with cercariae-infested freshwater, the parasite is spread to both human and nonhuman animal populations. Cercariae enters the epidermis and changes into an adaptable schistosomula that can evade the immune system of the host. The schistosomula move to the lungs in humans, where it matures and produce eggs (Adenowo et al. 2015). After the hatching of eggs in urine, the miracidia infect amphibious snails after entrance, resulting in the formation of sporocysts. The larval cercariae are then produced asexually by sporocysts (Ismail et al. 2014).
Imported African schistosomiasis and the potential risk of transmission in China
Published in Pathogens and Global Health, 2018
Jing Cui, Peng Jiang, Yan Yan Song, Xi Zhang, Zhong Quan Wang
African schistosomiasis is caused primarily by the blood flukes S. haematobium or S. mansoni. S. hematobium infection is endemic primarily in Africa and the Middle East, and causes urinary schistosomiasis. S. mansoni infection is distributed around the world, predominantly in Africa, the Near East, South America and the Caribbean, and produces intestinal schistosomiasis [1]. Both Schistosoma species are transmitted by intermediate host snails. Human infection is caused by skin contact with cercaria-contaminated freshwater during swimming, fishing or bathing. The principal clinical manifestations of S. haematobium infection are bladder irritation, hematuria, and urinal tract blockages, whereas the manifestations of S. mansoni infection are usually relatively mild, such as fever, abdominal pain, diarrhea, and weakness. Some patients may be mild or asymptomatic [5]. More than 90% of cases with African schistosomiasis occur in Africa, and China is a non-endemic area. However, an increasing number of Chinese citizens travel to Africa for work or leisure following the development of economic programs and tourism, the globalization of international trade, cultural exchange and China-aided projects in Africa. More than one million Chinese workers are working in Africa and approximately 900,000 Chinese people vacation in Africa each year [6]. There is an increasing trend for cases of African schistosomiasis in China. In this study, we report two cases of African schistosomiasis imported from Tanzania and Madagascar to China and discuss its potential transmission risk in China.