Sunday, 27 August 2017

SOURCES OF PARASITIC SOIL-TRANSMITTED HELMINTHS/WORMS

by Rishen Afakpo J. J.

Soil-transmitted helminths infections are among the most common infections worldwide and affect the poorest and most deprived communities. And they are also considered as Negleted Tropical Diseases, NTDs. This include; Roundworms (Ascaris lumbricoides), Whipworm (Trichuris trichiura), Hookworm (Necator americanus and Ancylostoma duodenale) and Strongyloides stercoralis. They are transmitted by eggs that are passed in the faeces of infected people. Adult worm live in the intestine where the produce thousands of eggs each day. In areas that lack adequate sanitation, these eggs contaminate the soil. This can happen in several ways;
1.     If infected person defecate outside (near bushes, in a garden or field) or if faeces of an infected person are used as fertilizer, eggs are deposited on soil.
2.     Eggs that are attached to vegetables or fruits are ingested when the vegetables or fruits are not carefully cooked or peeled.
3.     Eggs are ingested from contaminated water sources. This can happen through surface run-off rain water that washed the eggs in the soil and deposited in the water sources eg open well-water, lakes, sea, rivers, streams, ponds etc
4.     Eggs are ingested by children who plays in the contaminated soil and then put their hands in their mouth without washing them.
5.     And through long fingernails that are not properly taking care of.
Image result for ascaris lumbricoides
                          Ascaris lumbricoides removed from African child intestine

No direct person-to-person infection transmission or infection from fresh faeces, because eggs passed in faeces need almost three(3) weeks to mature in the soil before they become infective.
Hookworms and Strongyloides stercoralis eggs hatch in the soil releasing larvae that mature into a form that can easily penetrates the skin. People become infected with hookworms and Strongyloides stercoralis primarily by walking barefoot on the contaminated soil or beaches.
Image result for trichuris trichiura
Whipworm (Trichuris trichiura)

More than 1.5 billion people or 24% of the world population are infected with soil-transmitted helminths infections worldwide. Infections are widely distributed in tropical and subtropical areas, with the greatest number occurring in sub-saharan Africas, the Americas, China and Asia. Over 270 million pre-school age children and over 600 million school age children lives in areas where these parasites are intensively transmitted and are in need of treatment and preventive intervention. WHO, 2017.
According to Centre for Disease Control and prevention, CDC report 2017; approximately 807-1,121 million people are infected with Ascariasis, approximately 604-795 million of people are infected with Trichuriasis, approximately 576-740 million of people are infected with Hookworms and Strongyloidiasis worldwide.
Image result for ancylostoma duodenale
Hookworms

                                          NUTRITIONAL EFFECTS
Soil-transmitted helminths impair the nutritional status of the people the infect in multiple ways;
1.     The worms feed on host tissues, including blood, which leads to a loss of iron and protein, which eventually causes Anaemia.
2.     The worms increases malabsorption of micronutrients needed by the body. In addition, Roundworms may possibly compete for vitamin A in the intestine of its host.
3.     Some soil-transmitted helminths also cause loss of appetite and therefore, a reduction of nutritional intakes and physical fitness. In particular, T. trichiura can cause diarrhea and dysentery.
4.     Their infection can also lead to complications including ileus, that require surgical intervention.
Related image

                                 Strongyloides stercoralis

CONTROL AND PREVENTION
a.     Avoiding any and all contact with earth contaminated with human waste, especially faeces.
b.     Thoroughly washing hands with soap before handling food, especially when you come in contact with contaminated soil.
c.      Communicating to children the importance of washing hands as a means to prevent infection.
d.     Health and hygiene education in our primary and secondary schools.
e.     Washing, peeling and/or cooking all vegetables and fruits before consumption, especially in a case where they vegetables or fruits was grown in soil fertilized with manure.
f.       No defecating outdoors; using toilets connected to effective sewage disposal systems.
g.     Where possible,it is recommended that people in at-risk communities refrain from walking barefoot in areas where hookworms and Strongyloidiasis is prevalent and by all means avoid ingestion and playing in a dirt beaches soil.
h.     Provision of adequate sanitation is also important, but not always possible in resource-poor settings.
i.        Water supply sources should be well-protected from surface run-off water during rainfall.
j.       Cutting down-low your fingernails if you cant take good care of it.
k.     Periodic deworming with effective medicine; consult your doctor for advice on effective Anthelminthiasis medicines.

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