# Impact of asymptomatic Cryptosporidium infection on nutritional status in children under two: a multi-country cohort study

## TL;DR

Asymptomatic Cryptosporidium infections in young children are linked to malnutrition, including stunting and underweight, across multiple countries.

## Contribution

This study is the first multi-country cohort analysis showing that asymptomatic Cryptosporidium infections significantly impact child nutrition.

## Key findings

- Asymptomatic Cryptosporidium infections are associated with increased odds of stunting, wasting, and underweight in children under two.
- Infection incidence is highest in Tanzania and Peru, with notable regional differences in nutritional impacts.

## Abstract

Subclinical or asymptomatic cryptosporidiosis can contribute to malnutrition in children, especially in environments where the infection is persistent or occurs repeatedly. Despite the absence of symptoms, these infections are associated with impaired growth and nutritional deficiencies, potentially increasing the risk of stunting, wasting, and underweight. This study examined the association between asymptomatic Cryptosporidium infection and nutritional status in children under 2 years old.

This is a secondary analysis of data from the MAL-ED study which is a longitudinal birth cohort study conducted in eight countries: Bangladesh, Brazil, India, Nepal, Pakistan, Peru, South Africa, and Tanzania, a multi-country investigation of enteric infections and malnutrition. We excluded Pakistan due to the lack of available anthropometric data. Nutritional indicators were assessed using the World Health Organization growth chart,[18] including stunting (length-for-age <-2 standard deviations [SD]), underweight (weight-for-age <-2 SD), and wasting (weight-for-length <-2 SD). Poisson regression estimated Cryptosporidium incidence rates, while GEE (generalized estimation equation) with a binomial family and logit link assessed associations with nutritional indicators, calculating odds ratios.

Findings indicate an incidence rate of 7.89 per 100 child-months for asymptomatic Cryptosporidium infections, which are significantly associated with stunting (aOR: 1.32; 95% CI: 1.24–1.41), wasting (aOR: 1.47; 95% CI: 1.08–1.49), and underweight (aOR: 1.47; 95% CI: 1.08–1.49). Incidence was highest in Tanzania (14.35) and Peru (12.55), indicating a hidden burden, while Brazil (1.34) had the lowest. Stunting was strongly associated with infection in India, Peru, and Tanzania, underweight in Bangladesh and Tanzania, and wasting was notably high in Peru.

This study highlights the significant burden of asymptomatic Cryptosporidium infections and their potential impact on child growth and nutrition. The strong associations with stunting, wasting, and underweight suggest that even in the absence of symptoms, these infections may contribute to long-term developmental challenges. Furthermore, the differential effects on nutritional outcomes across countries emphasize the importance of targeted strategies to mitigate the hidden consequences of Cryptosporidium infections and improve child health globally.