Protozoal Infection
Protozoal infection is a broad label for illnesses caused by single-celled parasites. Different organisms affect the gut, blood or other organs, so symptoms alone cannot identify the correct treatment.
Key takeaways
- Diarrhoea, cramps and fatigue can occur with intestinal protozoa, but some species cause fever, anaemia or disease outside the gut.
- Travel, food and water exposure, immune status and stool or blood tests help identify the organism and severity.
- Metronidazole treats some protozoa but not all; using the wrong antimicrobial may delay effective care.
Catalogue matches do not identify the parasite or demonstrate that an antimicrobial is appropriate.
Why does the organism matter?
Giardiasis, amoebiasis and cryptosporidiosis can all cause diarrhoea, yet their treatment differs. Blood in stool, persistent fever or right-upper abdominal pain may indicate invasive or extra-intestinal disease and changes the assessment.
What does care depend on?
Hydration is important during diarrhoeal illness. Antiparasitic treatment depends on the confirmed or strongly suspected organism, illness severity, pregnancy, immune status and interactions. Some infections require no specific antimicrobial; others need specialist care.
When to seek urgent care
Seek urgent care for severe dehydration, fainting, confusion, persistent vomiting, heavy bloody diarrhoea, severe abdominal pain or high fever with rapid deterioration.