Soil-transmitted HelminthesYemeng Lu

Overview

Infectious Agents PrevalenceTransmissionHealth ProblemsTreatmentControl

Public health image library database (PHIL) of the US Centers for Disease Control (CDC)

The causal agents of soil-transmitted helminthiasis are three type of worms

Prevalence

Infectious Agents Transmission Health Problems Treatment Control

Ascaris lumbricoides (Roundworms)

Trichuris trichura (Whipworms)

Necator americanus and Ancylostoma duodenale (Hookworms)

Laboratory Identification of Parasites of Public Health Concern Image Library

PrevalenceInfectious Agents Transmission Health Problems Treatment Control

Partners for Parasite Control: Fact Sheet

Severe and heavy helminth infections cause more than 150,000 deaths

annually

PrevalenceInfectious Agents Transmission Health Problems Treatment Control

“Threehundredmillion people areseverely illdue toworms”

Partners for Parasite Control: Newsletter Issue 1

Worm burdens exhibit a highly aggregated (over dispersed) distribution

Certain individuals tend to be predisposed to heavy infections

• Genetics - Chromosome 1,13

• Behavior

• Poverty

PrevalenceInfectious Agents Transmission Health Problems Treatment Control

Soil-Based Helminths are transmitted via two mechanisms: ingestion and

penetration

Prevalence

Infectious Agents TransmissionHealth Problems Treatment ControlPartners for Parasite Control: Newsletter Issue 1

Prevalence

Infectious Agents TransmissionHealth Problems Treatment Control

A. lumbricoides is the largest of the intestinal nematodes affecting

humans

Soil-transmitted helminthes produce a wide range of intestinal, nutritional and developmental health problems.

Prevalence

Infectious Agents Transmission Health Problems Treatment Control

http://curezone.us/image_gallery/parasites/

STH infections are treatable with anthelmintic drugs ="deworming"

Prevalence

Infectious Agents Transmission Health Problems Treatment

Control

Modified from Helminth control in school-age children

Partners for Parasite Control

The cost of treatment is less than $0.25 per person per year.

STH infections are treatable with anthelmintic drugs ="deworming"

Prevalence

Infectious Agents Transmission Health Problems Treatment

Control

Roundworm

Whipworm

Albendazole impairs the assembly of microtubules in worm cells and

prevent glucose uptake

Albendazole

TubulinAssembly into microtubules

Cellular transport mechanisms

Worm intestinal cells

GlucoseRectal Expulsion

Anthelmintic drug treatmentcombined with improved sanitation and

health Education can reduce transmission and infection

Prevalence

Infectious Agents Transmission Health Problems Treatment ControlHelminth control in school-age children

Citation: Hotez PJ, Bundy DA, et al. Helminth Infections: Soil-transmitted Helminth Infections and Schistosomiasis.

In: Jamison DT, Measham AR, Alleyne G, eds. Disease Control Priorities in Developing Countries. 2nd ed. New York, NY: World Bank/Oxford University Press; 2006 Chapter 24.

De Silva N. R., Chan M. S., Bundy D. A. P. Morbidity and Mortality Due to Ascariasis: Re-estimation and Sensitivity Analysis of Global Numbers at Risk. Tropical Medicine and International Health. 1997; 2: 519–28.

Montresor A, Crompton DW, Gyorkos TW, Savioli L, et al. Helminth Control in School-age Children: A Guide for Managers of Control Programmes. Geneva, Switzerland: World Health Organization; 2002: 1-35.

Issue 1: Introduction. Action Against Worms. Partners for Parasite Control. March 2003. Fact sheet: Soil-transmitted helminthes. World Health Organization.

http://www.who.int/wormcontrol/documents/fact_sheets/soil_transmitted_helminths/en/index.html; 2010; April 2nd 2010.

Schmidt J. Effects of benzimidazole anthelmintics as microtubule-active drugs on the synthesis and transport of surface glycoconjugates in Hymenolepis microstoma, Echinostoma caproni, and Schistosoma mansoni. Parasitology Research. 1998 May;84(5):362-8.

Roos MH, Kwa MS, Veenstra JG, Kooyman FN, Boersema JH. Molecular aspects of drug resistance in parasitic helminths. Pharmacology & Therapeutics. 1993 Nov;60(2):331-6.

Lacey E. The role of the cytoskeletal protein, tubulin, in the mode of action and mechanism of drug resistance to benzimidazoles. International Journal for Parasitology 1988 Nov;18(7):885-936.

Ascariasis, Parasite and Health; Laboratory Identification of Parasites of Public Health Concern, Center for Disease Control; http://www.dpd.cdc.gov/dpdx/html/Ascariasis.htm; July 2009; April 2nd 2010.