Causes of acute diarrhea
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Infectious Causes of Acute Diarrhea: Bacteria, Viruses, and Parasites
Acute diarrhea is most commonly caused by infections from bacteria, viruses, or parasites. The specific pathogens involved can vary by age group, region, and exposure risks. Bacterial infections are often the leading cause in adults, while viral infections are more common in young children. Parasitic causes are less frequent but still significant in some settings Shen2016Blush2012Helou2024+4 MORE.
Bacterial Pathogens in Acute Diarrhea
Bacteria are a major cause of acute diarrhea, especially in adults and in cases related to contaminated food or water. The most frequently identified bacterial agents include:
- Salmonella species: A leading cause, especially Salmonella enteritidis Shen2016Giannella1981Cohen1991.
- Campylobacter jejuni: Common in both adults and children Shen2016Jewkes1981Helou2024+1 MORE.
- Enterotoxigenic Escherichia coli (ETEC): Frequently found in foodborne outbreaks and travel-related diarrhea Shen2016Giannella1981.
- Shigella species: Important in some regions, particularly in children Giannella1981Cohen1991.
- Clostridium difficile: Notable in adults, especially after antibiotic use or hospitalization Jewkes1981Blush2012.
- Other bacteria: Such as Yersinia enterocolitica, Bacillus cereus, Vibrio parahaemolyticus, and various coliforms, can also cause acute diarrhea .
Bacterial pathogens cause diarrhea through different mechanisms, including the production of enterotoxins (which stimulate intestinal secretion), direct invasion of the intestinal mucosa, and triggering inflammatory responses Giannella1981Blush2012.
Viral Causes of Acute Diarrhea
Viruses are the most common cause of acute diarrhea in children, particularly those under five years old. The main viral agents include:
- Rotavirus: The leading cause of severe diarrhea in young children worldwide Shen2016Quang2024Wilhelmi2003+1 MORE.
- Norovirus: A frequent cause in both children and adults, often associated with outbreaks Shen2016Helou2024Quang2024+1 MORE.
- Adenovirus and Sapovirus: Also contribute to cases, especially in children Shen2016Quang2024Wilhelmi2003.
- Astrovirus: Less common but still significant in pediatric cases Shen2016Wilhelmi2003.
Viral diarrhea is usually self-limited but can lead to dehydration, especially in young children Quang2024Wilhelmi2003Cohen1991.
Parasitic Causes of Acute Diarrhea
Parasitic infections are less common but can be important, particularly in areas with poor sanitation. The main parasites include:
- Giardia lamblia
- Cryptosporidium parvum
- Entamoeba histolytica (less frequently detected in some studies) Shen2016Cohen1991.
These parasites are typically transmitted through contaminated water or food and can cause both acute and chronic diarrhea Shen2016Cohen1991.
Noninfectious Causes of Acute Diarrhea
While infections are the most common cause, acute diarrhea can also result from noninfectious factors such as:
- Medication side effects (notably antibiotics, which can disrupt gut flora and lead to C. difficile infection) Jewkes1981Blush2012.
- Food allergies or intolerances.
- Acute gastrointestinal conditions (e.g., ischemia, endocrine disorders) Blush2012Meisenheimer2022.
Transmission and Risk Factors
Acute diarrhea is often spread through the fecal-oral route, contaminated food or water, person-to-person contact, or nosocomial (hospital-acquired) infections. Risk factors include recent travel, antibiotic use, hospitalization, and exposure to contaminated sources Blush2012Meisenheimer2022.
Differentiating Invasive and Noninvasive Causes
Invasive pathogens (such as Shigella, Salmonella, and Campylobacter) can cause inflammatory diarrhea with blood, fever, and abdominal pain, while noninvasive pathogens (such as most viruses and ETEC) typically cause watery, non-bloody diarrhea. Laboratory markers like fecal lactoferrin can help distinguish between invasive and noninvasive causes .
Conclusion
The causes of acute diarrhea are diverse and depend on age, region, and exposure. Bacteria (especially Salmonella, Campylobacter, and E. coli), viruses (notably rotavirus and norovirus), and parasites (such as Giardia and Cryptosporidium) are the main infectious agents. Noninfectious causes, including medication effects and acute GI conditions, should also be considered. Understanding the likely cause helps guide appropriate treatment and prevention strategies Shen2016Giannella1981Jewkes1981+7 MORE.
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