Protozoan Parasite and Gastroenteritis Quiz

Gastrointestinal Infections

• Gastroenteritis: inflammation of the stomach, small bowel, and large intestines, mostly caused by infectious agents, but can also be due to ingestion of certain drugs or toxins.
• Most common pathway: faecal-oral transmission of viruses, including Rotavirus, Norovirus, Astrovirus, and Adenovirus.

Aetiologies of Gastroenteritis

• Norovirus:
  • Referred to as the 'winter vomiting bug', but not limited to winter.
  • Highly transmissible, causing outbreaks in hospitals, nursing homes, schools, and cruises.
  • Contaminated food and waterborne transmission.
• Rotavirus:
  • Vaccine has been used routinely in Ireland since 2016, providing 82-94% protection against rotavirus types.
  • Two-dose oral vaccine, given at 2 and 4 months, must be given prior to 8 months of age.
• Entamoeba:
  • Protozoa that can burrow into intestinal walls and spread, causing septicemia and liver damage.
  • Source: foodborne, waterborne, fecal-oral, and prepared foods (usually cattle-related).

Clinical Presentation of Gastroenteritis

• Acute onset
• Anorexia
• Nausea and vomiting
• Watery diarrhoea
• Abdominal pain
• Fever
• Malaise
• Signs of dehydration: dry or cracked lips, poor skin turgor, tachycardia
• Severe dehydration: altered mental status, sunken eyes, weight loss

Diagnosis and Treatment of Gastroenteritis

• Diagnosis: usually made through history, but may require stool culture, microscopy, and PCR for viral aetiologies.
• Treatment:
  • Oral rehydration (rarely may need IV rehydration for severe dehydration)
  • Antidiarrheal agents (usually not needed)
  • Antiemetics (usually not needed)
  • Probiotics (may shorten duration of diarrhoea by one day)

Travelers' Diarrhoea

• Risk factors: development of diarrhoea in individuals from a resource-rich setting during or within 10 days of returning from travel to a resource-limited setting.
• Aetiologies: bacterial, viral, and parasitic, including ETEC, Campylobacter, Shigella, Norovirus, Rotavirus, Giardia, Cryptosporidium, Salmonella, and Vibrio.
• Presentation: malaise, anorexia, abdominal cramps, sudden onset of watery diarrhoea, lasting 1-5 days.
• Diagnosis: clinical diagnosis, testing not usually required, but can send stool for culture, microscopy, and toxin assay if prolonged symptoms or severe symptoms with fever.
• Treatment:
  • Fluids: frequent sips of diluted juice or electrolyte drinks
  • Solids: bland foods, avoiding dairy products
  • Antimicrobials: Azithromycin for severe symptoms
  • Symptomatic therapy: antidiarrheal agents, antimotility agents, and bismuth subsalicylate

Prevention of Travelers' Diarrhoea

• Avoid high-risk foods
• Wash hands before every meal
• Water purification: boiling, adding 5% bleach solution or iodine, or using water microfiltration systems
• Antimicrobials: pre-prescribing not recommended, unless immunocompromised host
• Vaccinations: ETEC vaccine is ineffective, but cholera vaccine is recommended for those traveling to endemic areas

Test your knowledge on a protozoan parasite that can cause severe watery diarrhea and learn about the inflammation of the gastrointestinal tract known as gastroenteritis. Explore sources of infection, clinical presentation, diagnostic testing, and treatment options.