Soil‐transmitted helminth parasites and allergy: Observations from Ecuador

Abstract

There is considerable interest as to potential protective effects of soil-transmitted helminths (STH) against allergy and allergic diseases. Here, we discuss findings of studies done of the effects of STH parasites on atopy and allergic diseases in Ecuador. While cross-sectional studies have consistently shown a reduced prevalence of allergen skin prick test (SPT) reactivity among infected schoolchildren, the removal of these infections by repeated deworming did not affect SPT prevalence over the short-term (ie, 12 months) but may have increased SPT prevalence over the long-term (ie, 15-17 years). In the case of allergic symptoms, cross-sectional studies have generally not shown associations with STH and intervention studies showed no impact on prevalence. However, a birth cohort suggested that early STH infections might reduce wheeze by 5 years. Allergic sensitization to Ascaris, however, explained a significant proportion of wheezing among rural schoolchildren. Studies of the effects of STH on immune and inflammatory responses indicated a potential role of STH in contributing to more robust regulation. The effects of STH on allergy are likely to be determined by history of exposure over the life-course and by interactions with a wide variety of other infectious and non-infectious factors.

Hemozoin From the Liver Fluke, Opisthorchis felineus, Modulates Dendritic Cell Responses in Bronchial Asthma Patients

“…In conclusion, our data demonstrate that Of Hz induces expression of Th1 cytokines in immature mouse DC and that Of Hz potentiates LPS-induced expression and production of IL-10 and IL-12β by DC in asthma patients. These results complement earlier findings that demonstrated the regulation of the host immune response by the helminth ES products, which play a protective role against allergy and allergic diseases (49), including findings in regions endemic for O. felineus , and that demonstrated the inverse relationship between opisthorchiasis and allergic diseases (31).…”

Trends in hospital admissions and mortality rates for asthma in Ecuador: a joinpoint regression analysis of data from 2000 to 2018

“…[7][8][9] In Ecuador, several studies have been conducted in the last two decades evaluating risk factors for asthma and other allergic diseases. [10][11][12][13][14] However, little attention has been given to temporal trends on hospitalisations and deaths attributed to asthma. For such a middleincome country, it is important to estimate morbidity and mortality of asthma to provide key information on the health impact and prioritisation of the disease for public health authorities.…”

Important Role of Immunological Responses to Environmental Exposure in the Development of Allergic Asthma

“…Anti-parasitic therapy is also shown to be associated with increased prevalence of asthma. 74 75 It was also noted that the prevalence of eczema in children would increase when their mothers accepted deworming treatment during pregnancy, while anthelminthic in children had no significant effect on eczema, 76 suggesting that the protective effect of allergies induced by parasite infection might begin in the mother's uterus.…”