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Infectious Diseases

Intestinal Worms (Helminths) - General

Infestation of the human intestines by various parasitic worms (helminths), commonly acquired through ingestion of eggs/larvae or skin penetration.

Also known as: Helminthiasis, Worm Infestation

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Referral and warning signs

When to refer

Refer if: Severe malnutrition or anaemia. Signs of intestinal or biliary obstruction. Suspected Strongyloides hyperinfection. Failure to respond to standard treatment.

Red flags

  • Signs of intestinal obstruction (abdominal distension, vomiting, constipation).
  • Severe anaemia.
  • Severe malnutrition.
  • Rectal prolapse.
  • Signs of hyperinfection in immunocompromised (sepsis, respiratory distress).

Signs and symptoms

  • Often asymptomatic or mild non-specific symptoms.
  • Symptoms depend on worm type and burden:
  • - Ascariasis (Roundworm): Abdominal discomfort/pain, cough (during lung migration - Loeffler's), malnutrition, passing worms (anus/nose/mouth), intestinal/biliary/pancreatic obstruction (heavy load).
  • - Enterobiasis (Pinworm/Threadworm): Intense perianal itching (pruritus ani), especially at night; disturbed sleep; visible small white worms around anus/in stool.
  • - Hookworm (Ancylostoma/Necator): Ground itch (dermatitis at penetration site), cough (lung migration), epigastric pain, iron-deficiency anaemia (chronic blood loss), fatigue, pallor, protein malnutrition (heavy load).
  • - Strongyloidiasis (Threadworm): Skin rash (larva currens), cough/wheeze (lung migration), abdominal pain, diarrhoea, weight loss. Hyperinfection syndrome in immunocompromised (severe, potentially fatal).
  • - Trichuriasis (Whipworm): Often asymptomatic. Heavy load: Frequent bloody/mucoid stools, abdominal pain, tenesmus, rectal prolapse (children), anaemia.

Risk factors

  • Poor sanitation and hygiene (faecal contamination of soil/water/food).
  • Lack of access to clean water.
  • Walking barefoot in contaminated soil (Hookworm, Strongyloides).
  • Eating contaminated raw/undercooked food.
  • Young age (children often heavily infected).
  • Living in endemic areas (tropical/subtropical regions).

Diagnosis

Clinical assessment

Suspicion based on symptoms (anaemia, malnutrition, abdominal pain, itching, passing worms) and epidemiological context.

Differential diagnosis

  • Other causes of abdominal pain, diarrhoea, anaemia, malnutrition.
  • Allergies (for itching).

Investigations

  • Stool Microscopy for Ova and Parasites (O&P): Main diagnostic method. Identifies characteristic eggs of Ascaris, Trichuris, Hookworm. Multiple samples may increase yield. Larvae seen in Strongyloidiasis.
  • Scotch Tape Test (for Pinworm): Pressing sticky tape to perianal area first thing in morning, examine tape under microscope for Enterobius eggs.
  • FBC: Eosinophilia common with tissue-migrating helminths; Microcytic anaemia in Hookworm/Trichuris.
  • Strongyloides serology (if suspected but stool negative).

Diagnostic criteria

Identification of worms, eggs, or larvae in stool or via specific tests.

Management

Non-pharmacological management

  • Improve sanitation and hygiene.
  • Nutritional support (manage anaemia/malnutrition).

Pharmacological treatment

  • Anthelmintic Drugs:
  • - Broad Spectrum (Ascaris, Hookworm, Trichuris, Enterobius):
  • - Albendazole 400mg PO single dose (Adult/Child >2y); 200mg single dose (Child <2y). (LOC: HC1+)
  • - OR Mebendazole 500mg PO single dose (Adult/Child >2y); 250mg single dose (Child <2y). OR 100mg BID for 3 days. (LOC: HC1+)
  • (Note: UCG uses <2y dose cutoffs; WHO often uses >1y for 500mg Mebendazole/400mg Albendazole)
  • - Strongyloidiasis:
  • - Ivermectin 200 mcg/kg PO single dose (repeated after 2 weeks sometimes recommended). (LOC: HC3+)
  • - Alternative: Albendazole 400mg PO BID for 7 days (UCG recommends 3 days).
  • - Enterobiasis (Pinworm): Treat entire household. Albendazole or Mebendazole as above, repeat dose after 2 weeks.
  • Iron Supplementation: For anaemia caused by Hookworm/Trichuris.
  • Mass Drug Administration (MDA): Periodic deworming (Albendazole/Mebendazole) for school-aged children in endemic areas (public health program).

Monitoring

Monitor symptom resolution. Repeat stool exam if symptoms persist. Monitor growth/nutrition in children.

Complications

  • Malnutrition, growth retardation, cognitive impairment (chronic infections in children).
  • Iron-deficiency anaemia (Hookworm, Trichuris).
  • Intestinal obstruction (heavy Ascaris load).
  • Biliary/pancreatic obstruction (Ascaris).
  • Rectal prolapse (heavy Trichuris load).
  • Strongyloides hyperinfection syndrome (in immunocompromised).

Prevention

  • Improved sanitation (latrine use, proper faecal disposal).
  • Access to safe water.
  • Personal hygiene (handwashing before eating/preparing food, after toilet use).
  • Food hygiene (washing fruits/vegetables).
  • Wearing shoes (prevents hookworm/strongyloides skin penetration).
  • Regular deworming programs in endemic areas (MDA).

Patient education

  • Explanation of worm infection and transmission.
  • Importance of taking medication as prescribed (single dose usually).
  • Need to treat family members (esp. for pinworm).
  • Hygiene and sanitation measures to prevent re-infection.
  • Importance of wearing shoes.
  • Nutritional advice.

Uganda-specific notes

Intestinal helminth infections are highly prevalent, especially among children. Soil-transmitted helminths (Ascaris, Trichuris, Hookworm) are common. Regular deworming through school health programs is a key control strategy. Albendazole/Mebendazole widely available.

References

  • Uganda Clinical Guidelines (UCG) 2023

    Chapter 2, Section 2.4.1

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