Parasites and allergy: Observations from Brazil

Abstract

Brazil is a middle-income country undergoing the epidemiological transition. Effects of changes in daily life habits and access to clean water, sanitation and urban services on a growing urban population have contributed to a double burden of both infectious and noncommunicable chronic diseases. Studies have indicated that parasite infections may modulate the human immune system and influence the development of allergic conditions such as asthma. However, there is no consensus in the published literature on the effects of parasitic infections on allergy, perhaps as a consequence of factors determining the epidemiology of these infections that vary between populations such as age of first infection, duration and chronicity of infections, parasite burden and species, and host genetic susceptibility. In this review, we discuss the observations from Brazil concerning the relationship between parasite infections and allergy.

Ascariasis as a model to study the helminth/allergy relationships

“…Związek między infestacją pasożytniczą i chorobą alergiczną jest przedmiotem wielu badań [1][2][3]. Złożoność tej relacji opisują różne teorie i koncepcje [4][5][6].…”

Association between allergic sensitization and intestinal parasite infection in schoolchildren in Gqeberha, South Africa

“…Infections with these parasites appear to have protective effects on the development of allergic sensitization and disease via an enhanced Th1-type immune response. 25,26 As South Africa is one of the most "westernized" nations on the African continent, we wondered whether atopy is as common amongst children in South Africa as it is in countries of the so-called…”

“…More evident, though much less studied thus far, seems to be the influence of protozoa on atopy. Infections with these parasites appear to have protective effects on the development of allergic sensitization and disease via an enhanced Th1‐type immune response 25,26 …”

Understanding Asthma and Allergies by the Lens of Biodiversity and Epigenetic Changes

“…The initial mechanistic explanation of the hygiene hypothesis emphasized the role of Th1 cells in regulating Th2 responses. Later, the role of regulatory T cells was emphasized in the regulation of both Th1 and Th2-induced inflammatory responses through mechanisms that include the production of regulatory cytokines ( 25 ). The mechanistic pathways of the hygiene hypothesis were described extensively in the literature, other theories amplified the initial concept such as the “old friends” hypothesis ( 26 ) and, afterwards, the biodiversity hypothesis, proposed by The Karelia Allergy Study from 1998 ( 27 ).…”