Soil Transmitted Helminth Infections

Key facts

  • Soil-transmitted helminth infections are caused by different species of parasitic worms.
  • They are transmitted by eggs present in human faeces, which contaminate the soil in areas where sanitation is poor.
  • Approximately 1.5 billion people are infected with soil-transmitted helminths worldwide.
  • Infected children are physically, nutritionally and cognitively impaired.
  • Control is based on:
    • periodical deworming to eliminate infecting worms
      health education to prevent re-infection
    • improved sanitation to reduce soil contamination with infective eggs.
  • Safe and effective medicines are available to control infection.

Soil-transmitted helminth infections are among the most common infections worldwide and affect the poorest and most deprived communities. They are transmitted by eggs present in human faeces which in turn contaminate soil in areas where sanitation is poor. The main species that infect people are the roundworm (Ascaris lumbricoides), the whipworm (Trichuris trichiura) and hookworms (Necator americanus and Ancylostoma duodenale).

Effectiveness of a rural sanitation programme on diarrhoea, soil-transmitted helminth infection, and child malnutrition in Odisha, India: a cluster-randomised trial
A third of the 2·5 billion people worldwide without access to improved sanitation live in India, as do two-thirds of the 1·1 billion practising open defecation and a quarter of the 1·5 million who die annually from diarrhoeal diseases. We aimed to assess the effectiveness of a rural sanitation intervention, within the context of the Government of India's Total Sanitation Campaign, to prevent diarrhoea, soil-transmitted helminth infection, and child malnutrition.

We did a cluster-randomised controlled trial between May 20, 2010, and Dec 22, 2013, in 100 rural villages in Odisha, India. Households within villages were eligible if they had a child younger than 4 years or a pregnant woman. Villages were randomly assigned (1:1), with a computer-generated sequence, to undergo latrine promotion and construction or to receive no intervention (control). Randomisation was stratified by administrative block to ensure an equal number of intervention and control villages in each block. Masking of participants was not possible because of the nature of the intervention. However, households were not told explicitly that the purpose of enrolment was to study the effect of a trial intervention, and the surveillance team was different from the intervention team. The primary endpoint was 7-day prevalence of reported diarrhoea in children younger than 5 years.

Soil-transmitted helminths refer to the intestinal worms infecting humans that are transmitted through contaminated soil ("helminth" means parasitic worm): Ascaris lumbricoides (sometimes called just "Ascaris"), whipworm (Trichuris trichiura), and hookworm (Anclostoma duodenale and Necator americanus). A large part of the world's population is infected with one or more of these soil-transmitted helminths:

Soil-transmitted helminth infection is found mainly in areas with warm and moist climates where sanitation and hygiene are poor, including in temperate zones during warmer months. These STHs are considered Neglected Tropical Diseases (NTDs) because they inflict tremendous disability and suffering yet can be controlled or eliminated.

Soil-transmitted helminths live in the intestine and their eggs are passed in the feces of infected persons. If an infected person defecates outside (near bushes, in a garden, or field) or if the feces of an infected person are used as fertilizer, eggs are deposited on soil. Ascaris and hookworm eggs become infective as they mature in soil. People are infected with Ascaris and whipworm when eggs are ingested. This can happen when hands or fingers that have contaminated dirt on them are put in the mouth or by consuming vegetables and fruits that have not been carefully cooked, washed or peeled. Hookworm eggs are not infective. They hatch in soil, releasing larvae (immature worms) that mature into a form that can penetrate the skin of humans. Hookworm infection is transmitted primarily by walking barefoot on contaminated soil. One kind of hookworm (Anclostoma duodenale) can also be transmitted through the ingestion of larvae.

We plan to do einterviews with MBBS doctors to understand 4 things
1) Tests or questions you ask in first few meetings
2) What it means in medical terms
3) What it means in non medical terms
4) What should the patient or care takers do

We might interview Aurvedic doctors, homeopathic doctors, Yoga teachers on this health issue

Video links
Deadly Worms!!! – A look at Soil Transmitted Helminths

Soil Transmitted Helminths

Soil Transmitted Helminthiasis
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