What pathogen is responsible for neonatal porcine diarrhea following infection?

Neonatal porcine diarrhea is primarily associated with infections caused by Cystoisospora (Isospora) suis, which is an internal parasite prevalent in piglets. This protozoan causes significant gastrointestinal distress, leading to diarrhea in young pigs. The impact is particularly pronounced in the early stages of life, where the parasite infects the intestinal epithelium, disrupting nutrient absorption and causing profuse watery diarrhea, which can lead to dehydration and even death if not managed promptly.

Cystoisospora suis is specifically known for its role in the first few weeks of life, coinciding with the period when piglets are particularly vulnerable due to an immature immune system. This organism's life cycle and the resulting illness are well documented, making it a primary concern for swine health management in neonatal populations.

In contrast, while Escherichia coli and Clostridium perfringens can also cause diarrhea in pigs, they tend to do so under different circumstances and are more often associated with post-weaning or environmental stress responses rather than neonatal diarrhea specifically linked to protozoan infection. Salmonella spp. are known for causing enteritis and systemic infections but are less commonly associated with the acute diarrhea seen in very young piglets. Thus