Summary

Soil Transmitted Helminths (STHs) are a group of intestinal nematode parasites that are transmitted to humans through soil contaminated with faecal matter. They are the most common infections of humankind, affecting approximately 1.5 billion people, or 24% of the world's population. These infections are intimately linked to poverty, poor sanitation, and lack of clean water.

The "Big Three" pathogens are:

1. Ascaris lumbricoides (Roundworm): The giant of the gut, causing obstruction and nutritional robbing.
2. Trichuris trichiura (Whipworm): The colon burrower, causing dysentery and prolapse.
3. Hookworm (Necator americanus and Ancylostoma duodenale): The blood suckers, causing iron deficiency anaemia.

While mortality is relatively low (approx. 135,000 deaths/year), the morbidity is enormous. STHs are a primary cause of physical growth stunting, intellectual retardation, and cognitive deficits in children in developing nations. They perpetuate the cycle of poverty by reducing the economic potential of infected populations. This has led to their classification as Neglected Tropical Diseases (NTDs) by the World Health Organization (WHO).

Key Facts

• Global Burden: >1.5 billion infected. 270 million preschool-age children and 600 million school-age children require preventive chemotherapy.
• Life Cycles: All involve a soil phase for egg maturation (hence "Soil Transmitted"). Direct person-to-person transmission is rare (eggs must embryonate in soil first).
• Ascaris Size: Female worms can grow up to 35cm long and live for 1-2 years.
• Hookworm Biology: A single Ancylostoma worm can consume 0.2ml of blood per day. A heavy burden equates to bleeding out a unit of blood every few weeks.
• Loeffler's Syndrome: A transient eosinophilic pneumonitis caused by larvae migrating through the lungs.
• Treatment: Remarkably effective with single-dose Albendazole (400mg) or Mebendazole (500mg), costing pennies per dose.

Clinical Pearls

[!TIP] The "Wormy" Cough: In a returning traveller or child from an endemic area, a dry cough with wheeze and eosinophilia is often the first sign of infection (Lung Migration Phase), occurring weeks before intestinal symptoms. Sputum may even contain larvae!

[!TIP] Anaesthesia Danger: Ascaris worms have a tendency to migrate into small orifices when stressed (e.g., by fever or anaesthetic gases). They can crawl up the oesophagus and block the endotracheal tube, or migrate into the biliary tree causing acute pancreatitis post-op.

[!TIP] The Hygiene Hypothesis: STH infection elicits a strong Th2 / IgE immune response. Epidemiological data suggests that populations with high worm burdens have significantly lower rates of autoimmune diseases (Crohn's, Asthma) and allergies, leading to research into "Helminthic Therapy".

Understanding the biological distinctions is crucial for clinical recognition.

3.1 Ascaris lumbricoides (Roundworm)

• Morphology: Large, cylindrical, creamy-white worms resembling earthworms.
  • Females: 20-35 cm. Straight tail.
  • Males: 15-30 cm. Curved tail with copulatory spicules.
  • Mouth: Three distinct "lips" with fine teeth.
• Egg Capacity: A single female lays 200,000 eggs per day. This immense output guarantees soil contamination.
• Lifespan: 1-2 years.
• Habitat: Jejunum (can migrate anywhere).

3.2 Trichuris trichiura (Whipworm)

• Morphology: Resembles a whip.
  • Anterior: Long, thin, thread-like end (the "lash") which burrows into the mucosal epithelium.
  • Posterior: Thick, handle-like end hangs freely in the lumen.
  • Size: 3-5 cm.
• Mechanism: The anterior stylet physically penetrates the cells of the caecum/colon, anchoring the worm. It does not vigorously suck blood but causes significant inflammation and mucosal friability.
• Habitat: Caecum and Ascending Colon.

3.3 Hookworm (Ancylostoma & Necator)

• Morphology: Small, greyish-white worms.
  • Size: ~1 cm (much smaller than Ascaris).
  • Mouthparts:
    • Ancylostoma duodenale: Two pairs of sharp teeth.
    • Necator americanus: Cutting plates.
• Feeding: They latch onto the mucosa, bite deep into capillaries, and secrete anticoagulants. The blood passes rapidly through their gut (wasting it) to extract nutrients.
• Lifespan: 1-5 years (Necator can live longer).

Each species has a unique journey through the human host.

4.1 Ascaris Life Cycle (The "Grand Tour")

The journey takes 2-3 months from ingestion to egg laying.

1. Ingestion: Embryonated eggs (infective stage) swallowed with food/water.
2. Hatching: Larvae hatch in the small intestine.
3. Hepato-Tracheal Migration:
   • Larvae penetrate the gut wall -> Portal Vein -> Liver.
   • Liver -> Inferior Vena Cava -> Heart -> Lungs.
4. Lung Phase (Days 4-14):
   • Larvae break out of pulmonary capillaries into alveoli.
   • They molt and grow, causing alveolar damage and eosinophilic inflammation (Loeffler's Syndrome).
   • They crawl up the bronchi and trachea ("The Ascending Trek").
5. Swallowing: The host coughs up the larvae and swallows them.
6. Maturation: Back in the small intestine, they mature into adults.

4.2 Hookworm Life Cycle (The "Skin Breakers")

1. Entry: Filariform larvae in warm, moist soil sense body heat/CO2 of a passing foot.
2. Penetration: They burrow through intact skin (usually interdigital spaces), causing "Ground Itch".
3. Migration: Blood -> Heart -> Lungs (same as Ascaris).
4. Swallowing: Coughed up and swallowed.
5. Attachment: Arrive in small intestine, bite into mucosa, and start blood feeding.

4.3 Trichuris Life Cycle (The "Direct Route")

No lung migration implies no Loeffler's syndrome.

1. Ingestion: Eggs swallowed.
2. Hatching: Larvae hatch in small intestine.
3. Migration: They move distally to the Caecum.
4. Burrowing: The thin anterior end threads itself into the epithelial tunnels of the colon lining.
5. Maturation: Occurs locally.

4.4 Immunology: The Th2 Response

Helminths are masters of immune modulation. They induce a potent Th2-polarized response:

• Interleukins: IL-4, IL-5, IL-13.
• Cells: Eosinophils, Basophils, Mast Cells.
• Antibodies: IgE (high levels).
• Function:
  • Expulsion: Increased mucus production ("Weep") and gut motility ("Sweep") attempts to flush worms out.
  • Tolerance: Worms secrete "Treg" inducing factors (TGF-beta) to dampen inflammation, preventing their own ejection but also reducing host allergies.

A systematic approach to the "Wormy Child".

General Inspection

• Anthropometry: Plot Hgt/Wgt/HC on growth charts. Look for crossing centiles downwards.
• Pallor: Check conjunctivae, palms, tongue.
• Oedema: Pedal oedema or ascites (Kwashiorkor-like) in severe hookworm.
• Finger Clubbing: Rare, but seen in chronic trichuris dysentery.

Abdominal Exam

• Distension: "Pot belly" appearance.
• Mass: In thin children, an Ascaris bolus may be palpable as a "doughy", mobile mass aka "Bag of Worms".
• Tenderness: Epigastric or Right Iliac Fossa.
• Rectal Exam: Check for prolapse.

Dermatological Exam

• Feet: Inspect web spaces for entry lesions.
• Cutaneous Larva Migrans: Creeping eruption (serpiginous track) if infected by dog/cat hookworm (A. braziliense).

Drugs alone are a stop-gap. Re-infection occurs within months without infrastructure change.

Water, Sanitation, Hygiene (WASH)

1. Sanitation: Construction of pit latrines or sewage systems. The single most effective intervention. Breaking the cycle of soil contamination stops all three parasites.
2. Water: Potable water supplies preventing need for contaminated surface water.
3. Hygiene Behavior:
   • Hand washing with soap (removes sticky Ascaris/Trichuris eggs).
   • Washing raw vegetables/peeling fruit.
   • Footwear: Wearing shoes/sandals completely prevents Hookworm infection.

Health Education

• School-based programs teaching "The Worm Cycle".
• Discouraging use of "Night Soil" (human excreta as fertilizer).

Outcome

• Individual: Excellent prognosis with treatment. Catch-up growth occurs rapidly. Anaemia resolves.
• Community: MDA programs have shown improved school attendance and future wage-earning potential in longitudinal studies (e.g., Bleakley epidemiology).

Economic Impact (The "Worm Tax")

Parasites act as a tax on development. A child with moderate worm burden forfeits 10-20% of their nutritional intake to the parasite. This leads to a less productive adult workforce. Eradication is estimated to have a Benefit-Cost ratio of 60:1, making it one of the "Best Buys" in global health.

Key Guidelines

• WHO (2017): Guideline: Preventive chemotherapy to control soil-transmitted helminth infections in at-risk population groups.
  • Recommendation: Annual deworming for all adolescent girls and women of reproductive age in endemic areas.
• CDC (2019): Yellow Book: Helminths, Soil-Transmitted.
  • Highlights the risk to travellers and expatriates.

Landmark Trials

1. The DEVTA Trial (2013): The largest cluster-randomized trial (1 million children in India). Showed little mortality benefit but significant reduction in morbidity.
2. Keiser et al (2008): Meta-analysis showing Albendazole superior for Hookworm, Mebendazole and Albendazole equal for Ascaris, both poor for Trichuris (single dose).

Viva Questions

1. Q: Describe the life cycle of Ascaris lumbricoides.
   • A: Ingestion -> Gut penetration -> Liver -> Heart -> Lungs (Molt) -> Trachea -> Swallow -> Intestine.
2. Q: What is Loeffler's Syndrome?
   • A: Pulmonary eosinophilia caused by larval migration. Cough, wheeze, infiltrates.
3. Q: A child presents with rectal prolapse. What is the organism?
   • A: Trichuris trichiura (Whipworm).
4. Q: Why do we treat pregnant women with Albendazole?
   • A: Hookworm anaemia causes LBW and maternal mortality. Benefit outweighs theoretical risk after 1st trimester.

OSCE Station

• Scenario: "Interpret this FBC for a child from rural Vietnam."
• Findings:
  • Hb 85 (Low)
  • MCV 70 (Low)
  • WCC 11.0 (Normal)
  • Eosinophils 2.5 (High)
• Synthesis: "This is a Microcytic Anaemia with Eosinophilia. The most likely diagnosis is Hookworm infection. I would request stool O&P and treat with Albendazole + Iron."

The "Old Friends" Mechanism

The Hygiene Hypothesis (or "Old Friends" Hypothesis) suggests that the human immune system co-evolved with helminths for millennia. The modern eradication of these parasites has left our immune systems "bored" and prone to attacking self-antigens.

1. T-Regulatory Cell (Treg) Induction:

   • Helminths secrete specific molecules (e.g., Ascaris Excretory/Secretory Products - AES) to interact with host Dendritic Cells.
   • This promotes the differentiation of naive T-cells into FoxP3+ Treg cells.
   • Tregs secrete IL-10 and TGF-beta, which are potent anti-inflammatory cytokines.

2. The Trade-off:

   • The helminth survives (immune evasion).
   • The host suffers less collateral damage from inflammation.
   • Bonus: This systemic anti-inflammatory state protects the host from Allergic Rhinitis, Asthma, Inflammatory Bowel Disease (IBD), and Type 1 Diabetes.

Therapeutic Potential

Clinical trials have explored using "clean" worms to treat autoimmune disease:

• Trichuris suis (Pig Whipworm): Used in trials for Crohn's Disease. It colonizes the gut briefly but doesn't reproduce in humans, inducing a beneficial Th2 shift without permanent infection.
• Necator americanus: Controlled infection with 10-20 hookworms has been trialed for Coeliac disease and MS.

The "Germ of Laziness"

In the early 20th century, the American South was plagued by poverty and lethargy. It was widely dismissed as a cultural failing until Charles Wardell Stiles identified Necator americanus ("The American Killer") as the cause.

The Rockefeller Sanitary Commission (1909)

• John D. Rockefeller donated $1 million to eradicate hookworm.
• This was one of the first true public health campaigns.
• Strategy:
  • Mapping infection rates.
  • Mass treatment (Thymol + Epsom salts).
  • Education ("Sanitary Privies" - teaching people to build outhouses).
• Result: Massive reduction in infection, correlated with a sharp rise in school enrollment and economic productivity in the Southern USA. This laid the foundation for modern global health philanthropy.

When medicine fails, the scalpel is needed. Ascaris Obstruction is a common cause of paediatric acute abdomen in the tropics.

The "Milking" Technique (Conservative Surgery)

1. Laparotomy: Midline incision.
2. Findings: The small bowel is packed with worms, feeling like a "bag of rubber tubes". The bowel wall may be thin and ischemic.
3. Milking:
   • Surgeon uses fingers to gently push the bolus distally through the ileocaecal valve into the capacious caecum.
   • Avoid: Squeezing too hard (ruptures worms -> toxic shock) or damaging the bowel wall.
4. Post-op: Administer Albendazole via NGT once bowel function returns.

Enterotomy (Invasive Surgery)

• Indication: If milking fails (impacted bolus) or bowel is necrotic.
• Procedure: Longitudinal incision on the bowel. Use sponge forceps to extract hundreds of worms.
• Closure: Transverse closure to prevent stricture.
• Risk: High rate of peritonitis and wound dehiscence due to poor nutritional state and contamination.

Disability Adjusted Life Years (DALYs)

STHs rarely kill, but they steal years of healthy life.

• Total DALYs: ~3.3 million years lost annually.
• Breakdown:
  • Hookworm: Causes the most DALYs due to anaemia affecting adult productivity and maternal health.
  • Ascaris: Affects child growth.
  • Trichuris: affects school attendance.

Cost-Effectiveness

Deworming is ranked by the Copenhagen Consensus as one of the most efficient investments in development.

• Cost: < $0.50 per child per year.
• Benefit: Increased lifetime wage earnings by >20% (due to better cognition/schooling).
• The "Worm Dividend": Removing worms liberates nutrients. A dewormed child absorbs more Vitamin A, Iron, and Protein from the same diet.

Animal worms can infect humans but cannot complete their life cycle, leading to "wandering" behaviour.

Cutaneous Larva Migrans (CLM)

• Cause: Ancylostoma braziliensis (Dog/Cat Hookworm).
• Scenario: Sunbathers on tropical beaches (sand contaminated by stray dogs).
• Sign: "Creeping Eruption". Intensely itchy, serpiginous red track that moves 1-2cm per day.
• Treatment: Topical Tiabendazole or oral Ivermectin.

Visceral Larva Migrans (VLM) / Toxocariasis

• Cause: Toxocara canis (Dog Roundworm).
• Pathology: Larvae migrate to Liver (Hepatomegaly), Lungs (Wheeze), or Eyes (Ocular Larva Migrans - can cause blindness, mimicking Retinoblastoma).
• Prevention: Regular deworming of pets. Covering sandpits.

For hospitals in endemic areas:

Key Performance Indicators (KPIs)

1. Anaemia Screening: % of children with anaemia screened for Hookworm.
2. Treatment Coverage: % of identified cases treated within 24 hours.
3. Surgical Outcomes: Rate of post-op complications in Ascaris obstruction.
4. Public Health: Notification of clusters to local health authority for water testing.

Audit Standards

• Standard: All patients with Eosinophilia > 1.0 should have 3 stool samples checked.
• Target: 100%.

Case 1: The "Asthmatic"

• Scenario: 6yo girl treated for "Asthma" for 3 months with steroids. Worsening cough and infiltrates on CXR. Developed severe abdominal pain.
• Outcome: Laparotomy revealed Ascaris obstruction. The "Asthma" was Loeffler's syndrome.
• Lesson: Steroids can disseminate strongyloides/ascaris. Always consider parasites in the "Unusual Asthma" differential, especially with eosinophilia.

Case 2: The "Appendicitis"

• Scenario: 12yo boy with RIF pain. Appendectomy performed. Appendix was normal, but a worm was found exiting the stump later, causing a fistula.
• Lesson: In endemic areas, "Worm Colic" mimics appendicitis. If appendix is normal at surgery, check the lumen for worms.

Q: Can I catch worms from my dog? A: You can catch different worms (like Toxocara), but you generally don't catch human roundworms from pets. However, pet hygiene is crucial.

Q: Do I need to treat the whole family? A: Yes. If one child has worms, it is very likely others do too, as you share the same environment and food sources.

Q: Will I see the worms when I take the medicine? A: Usually no. The medicine paralyzes and dissolves them, so they pass unnoticed in the stool. Occasionally, with heavy Ascaris infection, you might pass a recognizable dead worm.

Q: Can I get immunity? A: No. You can get infected again and again. This is why regular deworming is needed until sanitation improves.

Q: Is the medicine safe? A: Extremely safe. Side effects are rare and mild (minor tummy upset).

As elimination targets near, simple microscopy becomes less sensitive.

FLOTAC and Mini-FLOTAC

• Principle: Uses a flotation apparatus with zinc sulphate to separate eggs from faecal debris.
• Advantage: Significantly higher sensitivity than Kato-Katz for light infections (essential for monitoring eradication).
• Use Case: Clinical trials and post-MDA surveillance.

qPCR (Quantitative PCR)

• Mechanism: Detects parasite DNA in stool.
• Benefit: Can distinguish between Necator americanus and Ancylostoma duodenale (which look identical under microscope).
• Multiplexing: Can test for Ascaris, Trichuris, Hookworm, and Strongyloides in one run.

The engineering solution to a medical problem.

The Problem with Pit Latrines

Standard pit latrines smell and attract flies. Flies feed on faeces, pick up eggs on their legs, and land on food (Mechanical Vector).

The Solution: Ventilated Improved Pit (VIP) Latrine

1. Vent Pipe: A tall black pipe extends from the pit above the roof.
2. The Physics: Using the Bernoulli principle and solar heating, air is drawn down the hole and up the pipe. This sucks smells away from the user.
3. Fly Screen: The top of the pipe has a mesh screen. Flies are attracted to the light at the top of the pipe, fly up, get trapped by the screen, and die.

Safe Water Storage

• Ascaris eggs are sticky and resistant to standard chlorination.
• Filtration: Ceramic filters or Slow Sand Filtration are required to physically remove ova.
• Solar Disinfection (SODIS): UV radiation kills larvae but requires clear PET bottles and 6 hours of sun.

How worms steal health at a molecular level.

Vitamin A Malabsorption

• Mechanism: Ascaris worms inhibit host pancreatic enzymes (trypsin/lipase). Vitamin A is fat-soluble. Without lipid digestion, Vitamin A is not absorbed.
• Consequence: Night blindness (Xerophthalmia) and reduced immune competence (Measles mortality increases).

Zinc Deficiency

• Mechanism: Chronic intestinal inflammation leads to loss of endogenous zinc.
• Consequence: Stunted height, diarrhea, and immune failure.

The "Iron Trap"

• Hookworms secrete metalloproteases to degrade hemoglobin.
• They only use tiny amounts for their own metabolism. The rest is excreted as "haematin" (black pigment). They are incredibly inefficient feeders, wasting 90% of the blood they tap.

The Hookworm Vaccine (Na-ASP-2)

• Target: Necator americanus Ancylostoma Secreted Protein-2.
• Mechanism: Induces antibodies that neutralize the enzymes the worm needs to digest blood.
• Status: Phase 1 trials showed safety but highlighted urticarial reactions in previously infected individuals.

New Anthelminthics

• Tribendimidine: A Chinese drug showing good efficacy against Hookworm and Ascaris.
• Oxantel Pamoate: Specifically effective against Trichuris (the weak spot of Albendazole). Future regimens may combine Albendazole + Oxantel.

"Kwame, aged 7, sat at the back of the classroom in rural Ghana. He was small for his age, with distended abdomen and thin, rusty-coloured hair. He couldn't concentrate on the blackboard; he was too tired. During recess, while other boys played football, he sat under a tree. He had never worn shoes.

When the School Health Programme arrived, he was given a single chewable tablet. Two days later, his mother was horrified to see a tangle of large white worms in the latrine. But within weeks, Kwame changed. His energy returned. His cheeks turned pink. He started playing football. He moved to the front of the class."

• Clinical context: This narrative illustrates the "insidious" nature of chronic infection—it doesn't kill, it just steals potential. The rapid reversibility with cheap treatment is the key message.

Specific professions are at extreme risk.

• Tea Plantation Workers: High risk of Hookworm. The tea bushes provide shade and moisture (perfect for larvae). Pluckers often work barefoot.
• Rice Farmers: Risk of Schistosomiasis and Strongyloides from wading in water/mud.
• Miners: Historical "Miner's Anaemia". Warm, humid, dark underground tunnels were perfect breeding grounds for Hookworm (transferred via bucket latrines).

In Mass Drug Administration (MDA), consent is handled differently.

• Implied Community Consent: Health ministries authorize the program.
• Opt-out: Parents are informed (radio, posters) and can keep children home if they object.
• Safety Net: Teachers are trained to recognize adverse events (choking, allergies).
• Key Warning: "Tell the children they might pass worms. It is scary but normal."

For individual patients treated in clinic:

1. Hygiene: "Wash all bed linen in hot water (>60°C) to kill eggs."
2. Nails: "Cut fingernails short and scrub with a nail brush."
3. Follow-up: "Come back in 3 months if symptoms recur."
4. Family: "Bring your siblings for a check-up."
5. Diet: "Eat plenty of green leafy vegetables and meat/beans to rebuild your iron stores."

Beta-Tubulin Mutations & Resistance

• Mechanism of Resistance: A Single Nucleotide Polymorphism (SNP) at codon 200 (F200Y) of the beta-tubulin gene prevents Benzimidazoles from binding.
• Current Status: Widespread in veterinary parasites (sheep/goats) due to overuse. Rare in human STHs currently, but a major threat to MDA sustainability.
• Surveillance: Use qPCR to monitor for the F200Y mutation in community stool samples.

Pharmacokinetics

• Absorption: Albendazole is poorly absorbed (<5%).
• Fatty Meal:Taking with fatty food increases absorption by 5x.
  • For Intestinal Worms: Take on Empty Stomach (we want the drug in the gut, not the blood).
  • For Hydatid Cyst / Neurocysticercosis: Take with Fatty Meal (we want systemic absorption).

The worm's outer shield is an engineering marvel.

The Hydrostatic Skeleton

• Pressure: The internal pressure of Ascaris is extremely high (up to 225 mmHg, higher than human systolic BP). This keeps the worm cylindrical and prevents it from being crushed by peristalsis.
• Collagen: The cuticle is made of multiple layers of collagen fibers arranged in a lattice.
• Evading Acid: The cuticle is chemically resistant to human pepsin and hydrochloric acid. If the worm dies (e.g., after Albendazole), this protection fails, and the worm is rapidly digested by the host (appearing as "soup" in the stool).

Is total eradication desirable?

The "Biome Depletion" Theory

• Some evolutionary biologists argue that worms are "micro-livestock" that we have co-existed with for 100,000 years.
• Consequence of elimination: A sharp rise in autoimmune diseases, allergies, and metabolic syndrome in developed nations.
• The Future: We may need to re-introduce "therapeutic helminths" or their molecular signals to keep our immune systems regulated.

• 1550 BC: The Ebers Papyrus describes Ascaris and recommends Pomegranate root as treatment.
• 1758: Linnaeus classifies Ascaris lumbricoides.
• 1838: Dubini discovers Hookworm in Milan.
• 1909: Rockefeller Sanitary Commission founded.
• 1977: Introduction of Mebendazole (Janssen).
• 2012: London Declaration on NTDs aimed at control by 2020.
• 2030: Current WHO target for elimination of morbidity (<2% prevalence of heavy intensity infections).

For use in rural district hospitals managing "Worm Bolus".

Pre-operative

1. Hydration: Resuscitate with Normal Saline (vomiting causes dehydration).
2. NG Tube: Large bore (14-16F) to decompress stomach.
3. Imaging: Plain Abdominal X-Ray (Supine and Erect).
4. Antibiotics: Ceftriaxone + Metronidazole (translocation of bacteria is common).

Peri-operative

1. Examination: Run the whole bowel (multiple obstruction points?).
2. Milking: Be gentle. Distal progression is safer than proximal.
3. Check for Perforation: Look closely at the pressure points where the bolus was impacted.
4. Biliary Check: Palpate the CBD.

Post-operative

1. Deworming: Administer Albendazole via NG tube on Day 2/3 (when bowel sounds return).
2. Nutrition: Early feeding to repair gut mucosa.

• Pigs: Ascaris suum is genetically almost identical to A. lumbricoides. In farming communities, pigs are a reservoir. Eradication in humans may fail if pigs are not treated.
• Dogs: Source of Toxocara and Ancylostoma.
• Strategy: Integrated pest management involving veterinarians in public health boards.

• Warming: Higher ground temperatures accelerate egg maturation in soil.
• Expansion: Hookworm may move to previously cooler high-altitude regions (e.g., Andes, Himalayas).
• Flooding: Extreme weather events spread faecal contamination into water tables, causing outbreaks.

For a Community Health Worker teaching a village.

1. Prop: Use a long piece of cooked spaghetti to represent an Ascaris worm.
2. Demo: Show how it tangles (obstruction).
3. Visual: Show a picture of a "VIP Latrine" vs "Open Defecation".
4. Action: Hand washing demonstration with soap + "Happy Birthday" song (20 seconds).
5. Take-home: "Shoes protect your blood."

• Bill & Melinda Gates Foundation: Major funder of NTD programs.
• USAID: Neglected Tropical Diseases Program.
• Drug Donations:
  • GSK donates Albendazole.
  • Johnson & Johnson donates Mebendazole.
  • This "Drug Donation" model supports the entire global eradication effort.

• Geohelminth: A worm that requires a period of development in the soil to become infective.
• Embryonation: The process by which a fertilized egg develops a larva inside it.
• Rhabditiform Larva: The non-infective first stage larva that hatches in the soil (Hookworm).
• Filariform Larva: The infective third stage larva that penetrates skin.
• Night Soil: Human faeces used as fertilizer (major source of transmission).
• Pica/Geophagia: The compulsion to eat soil (often a sign of Iron Deficiency, but also causes re-infection).
• Intensity: The number of worms/eggs in an individual (Worm Burden).
• Prevalence: The percentage of the population infected.
• Morbidity Control: Reducing intensity so that disease symptoms disappear, even if infection remains.

To be commissioned from Medical Illustration Team.

Title: Keeping Your Family Worm-Free

What are worms? Worms are tiny parasites that live in the tummy. They steal your child's food and energy. They come from dirt and soil.

How do you prevent them?

1. SHOES: Always wear shoes or sandals outside. Hookworms get in through bare feet.
2. HANDS: Wash hands with soap before eating and after the toilet.
3. WATER: Drink only clean or boiled water.
4. TOILET: Use a latrine. Never go to the toilet in the bushes or near the house.

The Medicine The tablet (Albendazole) is safe. Your child should take it every 6 months if the school offers it. It kills the worms and helps your child grow tall and smart.

Warning Signs Go to the clinic if your child has:

• A swollen pot-belly.
• Pale skin or palms.
• Vomits a worm.
• Coughs for a long time without a cold.

• WHO Integrated Management of Childhood Illness (IMCI)
• NICE CKS: Intestinal Worms

Review Cycle: Annual Next Review: Dec 2026 Approving Body: MedVellum Medical Board