# Influence of Cryptosporidium and rotavirus co-infection on infectivity in calves

## TL;DR

This study explores how co-infection with rotavirus and Cryptosporidium affects disease severity in calves and suggests a potential new approach for controlling these infections.

## Contribution

The study reveals that bovine rotavirus can reduce the severity of Cryptosporidium infection in calves, offering a novel strategy for disease control.

## Key findings

- Subclinical rotavirus infection shortened the duration of Cryptosporidium-induced diarrhea in calves.
- Bovine rotavirus NSP4 protein inhibits Cryptosporidium parvum infection in vitro, possibly via interference with SGLT1.

## Abstract

Rotavirus A (RVA; species Rotavirus alphagastroenteritidis) and Cryptosporidium spp. are major enteric pathogens in infants and neonatal calves, causing severe diarrhea that can lead to fatal outcomes. These pathogens thus pose challenges in both public health and the livestock industries. Although co-infections are common, their pathogenesis remains poorly understood. Here, we conducted a longitudinal investigation in naturally infected calves to assess the impact of co-infection with rotavirus and Cryptosporidium. Infection status was determined based on daily fecal antigen testing and oocyst per gram (OPG) counts from birth to 22 days of age. Based on these criteria, seven calves were classified as having Cryptosporidium mono-infection and three calves as having mixed infection. We found that subclinical infection with bovine rotavirus significantly shortened the duration of diarrhea caused by Cryptosporidium parvum in calves and reduced initial oocyst shedding. Furthermore, in vitro experiments using the bovine intestinal epitheliocyte (BIE) cell line demonstrated that the BRV Lincoln strain (G6, P[1]) non-structural protein 4 (NSP4) inhibits C. parvum infection, possibly by interfering with the host sodium-glucose co-transporter 1 (SGLT1). Our study highlights a potential novel strategy for controlling both BRV and C. parvum by exploiting their interactions during co-infection.