Giardia lamblia risk factors and burden in children with acute gastroenteritis in a Nicaraguan birth cohort

Abstract

Background: Giardia lamblia is an intestinal protozoan estimated to cause ~200 million symptomatic infections annually, mainly in children in low- and middle-income countries associated with intestinal damage, increased permeability, and malabsorption.

Methods and results: We describe here the epidemiology, incidence, clinical characteristics, and risk factors of acute gastroenteritis episodes (AGE) with G. lamblia detection (GAGE) using a birth cohort of 443 Nicaraguan children followed weekly until 36 months of life. From June 2017 to July 2021, 1385 AGE samples were tested by qPCR. G. lamblia was detected in 104 (7.5%) of AGE episodes. In all, 69 (15.6%) children experienced at least one GAGE episode, and 25 of them (36.2%) experienced more than one episode. The incidence rate of the first episode of GAGE was 6.8/100 child-years (95% CI, 4.5-9.1). During GAGE, bloody stools, vomiting, and fever were uncommon, and children were less likely to be treated at a primary care clinic, suggesting that GAGE is typically mild and most cases did not receive medical attention, which could facilitate higher parasite loads with increased possibilities of establishing chronic carriage. GAGE was more common in children 12-24 months of age (13.9/100 child-years [95% CI, 10.7-17.1]) as compared to other age groups. In our birth-cohort, children living in a home with an indoor toilet (aHR, 0.52 [95%CI, 0.29-0.92]), and being breastfed in the first year of life (aHR: 0.10 [95%IC, 0.02, 0.57]) had a lower incidence of GAGE. In contrast, being breastfed for ≤ 6 months was associated with a higher incidence if the children were living in houses without indoor toilets and earthen floors (HR, 7.79 [95% CI, 2.07, 29.3]).

Conclusion: Taken together, GAGE is more frequent under poor household conditions. However, breastfeeding significantly reduces the incidence of GAGE in those children.

Fig 1. Incidence and frequency of G. lamblia detection in acute gastroenteritis episodes (GAGE) in a birth cohort until 3 years of age.

Number of AGE episodes reported by month (left axis), no-GAGE (gray points), and GAGE (black points) in 1385 diarrhea stools. Incidence rate for first GAGE detection in 443 children followed up 36 months (right axis).

Fig 2. Co-pathogens detected in acute gastroenteritis episodes with G. lamblia detection (GAGE) (n = 76).

A) Co-pathogens stratified by bacteria, virus and parasite detections (n = 61) and Mono-infection with G. lamblia group was stratified by the first GAGE. B) Percentage of co-infection by etiology. ^§All pathogens were detected by qPCR. ETEC: Enterotoxigenic Escherichia coli, EPEC: Enteropathogenic E. coli. EIEC: Enteroinvasive E. coli, EAEC: Enteroaggregative E. coli. STEC: Shiga Toxin-producing E. coli. ^αInclude both heat-labile and heat-stable toxins. ^βInclude both typical and atypical strains. ^¥Include both Shiga-toxin (SXT) STX-1 and STX-2.

Fig 3. Cumulative incidence and hazard ratios of first GAGE detection and along the first 3 years of life in children with presence of risk factors associated stratified by breastfeeding compliance (determined according to the number of weeks the mother reported any breastfeeding, exclusive or not, in the first 6 months).

Children were classified as receiving breastfeeding during at least 90% of weeks in the first six months of life “≥6 months breastfeeding” or less than 90% of weeks in the first 6 months of life “<6 months breastfeeding” living in: A) household without an indoor toilet (n = 122). B) household with earthen floor (n = 134). C) household that both have no indoor toilet and having earthen floor (n = 82). D) presence of mice in the home (n = 398). AGE: Acute Gastro-Enteritis. GAGE: Acute Gastro-Enteritis with presence of G. lamblia. ^¥Time-varying risk factors (corresponds to data reported in the week prior to assessment of the outcome). *P<0.050 to 0.010, **P<0.010 to 0.001, ***P<0.001.