Helminth Reinfection Essay

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Introduction
Parasitic helminth infections are an important burden to global public health, causing great morbidity in humans and livestock. Estimates claim that up to a quarter of the world´s population is affected by soil-transmitted helminths (1), although the incidences are mainly restricted to developing countries, due to poor sanitation resources and health care. Considering these facilities are relatively modern, it is likely that until the 19th century all human beings were infected throughout most of their life by one or more helminth species (2).
Helminth infections have been present throughout the entire human evolution, among which some were actually inherited by our primate ancestors (3). These millennia of coexistence have driven
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Primary H. polygyrus infections are generally chronic and asymptomatic in wild-type mice, causing only moderate intestinal pathology without seemingly affecting overall health (31). However, when the infection is cleared with anti-helminthic drug treatment and the mice are subsequently re-infected, a strong memory response is generated that expels the worms in about 12 days after challenge (25,32). The exact mechanisms of this highly effective memory response upon reinfection is poorly understood, but it is generally accepted that both humoral and cellular components are necessary for a protective immunity, whereby IL-4 and IL-13 play a key role …show more content…
polygyrus, containing many host immunity homologues, but the function of others remain unknown (45). The most abundant protein group found in HES is to the highly divergent venom allergen-like (VAL) proteins, containing 25 identified homologues (46,47). These are related to the Ancylostoma secreted proteins (ASPs), a family also known as SCP/TAPS proteins, and is widely expressed among different parasitic helminths (43,48,49). The VAL proteins present a conserved structure around a single or two tandem SCP domains containing about 200 amino acids (46). The first protein that was classified as a VAL protein was isolated from Brugia malayi and was identified as an ASP homologue (50,51). VAL proteins have since been found in a range of other helminths, such as Schistosoma mansoni and Heligmosomoides polygyrus (46,52), and much focus is put on determining their relevance in infection and their immunomodulary

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