How to Check for Infection in the Intestine?

How to Diagnose an Intestinal Infection Testing Guide

Intestinal infections, also known as gastrointestinal infections, are caused by bacteria, viruses, or parasites that enter the digestive system. They can affect the small intestine, large intestine, or both and lead to symptoms such as diarrhoea, stomach cramps, nausea, and fever.

Detecting an intestinal infection requires observing clinical symptoms, undergoing medical tests, and interpreting diagnostic results. Continue reading to learn how to test for an intestinal infection, including its causes, symptoms, and diagnostic methods.

Causes of Intestinal Infections

Intestinal infections are most commonly caused by the following:

• Bacteria –Salmonella, Shigella, E. coli, Campylobacter, Clostridium difficile.
• Viruses –Rotavirus, Norovirus, Adenovirus.
• Parasites –Giardia lamblia, Entamoeba histolytica, Cryptosporidium.

These pathogens are often transmitted through:

• Contaminated food or water
• Poor hygiene practices
• Close contact with infected individuals
• Consumption of raw or undercooked meat

In some cases, weakened immunity, recent hospitalisation, or the use of certain medications (such as antibiotics or immunosuppressants) may increase susceptibility to intestinal infections. Infants, older adults, and individuals with chronic conditions are especially at higher risk of severe outcomes.

Common Symptoms of Intestinal Infection

Before testing for an intestinal infection, it is essential to recognise the symptoms. They include:

• Diarrhoea (watery or bloody)
• Abdominal pain or cramps
• Bloating and gas
• Nausea and vomiting
• Fever
• Urgent need to defecate
• Fatigue and weakness
• Dehydration (dry mouth, reduced urination, dizziness)

Additional symptoms like unintended weight loss, foul-smelling stools, or persistent fatigue may occur, especially with parasitic or chronic bacterial infections in prolonged or severe cases. If symptoms persist for more than a few days or worsen, it is essential to consult a healthcare provider.

Diagnostic Tests to Detect Intestinal Infections

Clinical Evaluation

The first step in diagnosing an intestinal infection involves a physical exam and medical history review. Your doctor will ask about:

• Recent travel history
• Dietary habits
• Onset and duration of symptoms
• Exposure to contaminated food/water or sick individuals
• Use of antibiotics (linked to C. difficile infections)

A physical examination may reveal tenderness in the abdominal area, signs of dehydration, or fever.

Stool Tests (Faecal Analysis)

This is the most direct method for confirming an intestinal infection:

• Stool Culture: Identifies bacteria like Salmonella, Shigella, or Campylobacter.
• Ova and Parasites Test: Detects parasitic infections like Giardia or Entamoeba.
• PCR Test: Detects the DNA of specific pathogens, including viruses and antibiotic-resistant bacteria.
• Clostridium Difficile Toxin Test: Confirms infections caused by C. difficile, especially after antibiotic use.
• Occult Blood Test: Identifies hidden blood in the stool, which may indicate a more severe infection. These tests detect microscopic blood but are less specific for acute infections.

Blood Tests:

Blood tests are used to assess the body's immune response and rule out systemic infections:

• Complete Blood Count (CBC):An elevated white blood cell (WBC) count indicates infection.
• C-Reactive Protein (CRP) or Erythrocyte Sedimentation Rate (ESR):These markers rise in response to inflammation.
• Blood Cultures: Help detect if the infection has spread into the bloodstream.

Imaging Tests

While not always necessary, imaging may be done if complications or severe infections are suspected.

• Abdominal X-ray: To check for bowel obstructions or gas buildup.
• Ultrasound or CT Scan: Used when abscesses, perforations, or inflammation (such as colitis) are suspected.

Endoscopy or Colonoscopy

For chronic or unexplained infections, especially if blood is present in the stool or there's suspicion of diseases like inflammatory bowel disease (IBD), a doctor may recommend:

• Colonoscopy: Allows for visual inspection and biopsy of the colon.
• Upper Endoscopy: For infections suspected in the upper part of the small intestine.

Preventive Measures for Intestinal Infection

While diagnosis is important, prevention is always better. Here are the following ways to prevent intestinal infection:

• Drink clean, purified, or boiled water.
• Practise hand hygiene, especially after using the restroom and before meals.
• Cook food thoroughly.
• Wash fruits and vegetables properly.
• Avoid street food in high-risk areas.
• Use probiotics (with medical advice) to maintain gut flora.
• Avoid sharing personal utensils and towels during an active infection phase.

Treatment of Intestinal Infection

Treatment depends on the cause. The following are the ways to treat intestinal infection:

• Hydration is Key– Oral rehydration solutions (ORS) or IV fluids in severe cases
• Antibiotics– For bacterial infections (e.g., Shigella, Campylobacter); only under prescription
• Antiparasitic Medications– Like metronidazole for Giardia or Entamoeba
• Antidiarrheal Agents– Such as loperamide, but only under medical guidance
• Probiotics– Help restore good gut bacteria
• Dietary Adjustments– Bland, non-irritating foods; avoid dairy and greasy items

Patients are also advised to rest and avoid caffeine, alcohol, and sugary foods during recovery. In children and older adults, extra care is required to manage dehydration and electrolyte imbalance.

Detecting an intestinal infection involves a careful combination of symptom analysis and medical testing. From stool analysis to imaging and endoscopy, each diagnostic method helps pinpoint the source and nature of the infection, ensuring timely and accurate treatment.

Star Health covers consultations, diagnostics, and treatments for gastrointestinal infections to enable individuals to receive quality medical care during such situations. Early detection not only reduces suffering but also prevents complications. Therefore, paying attention to symptoms and getting tested promptly is crucial for maintaining good digestive and overall health.