Epidemiology and control of human gastrointestinal parasites in children

Abstract

Parasites found in the human gastrointestinal tract can be largely categorized into two groups, protozoa and helminths. The soil-transmitted helminths (Ascaris lumbricoides, hookworm and Trichuris trichiura) are the most prevalent, infecting an estimated one-sixth of the global population. Infection rates are highest in children living in sub-Saharan Africa, followed by Asia and then Latin America and the Caribbean. The current momentum towards global drug delivery for their control is at a historical high through the efforts of numerous initiatives increasingly acting in coordination with donors, governments and local communities. Together, they have delivered enormous quantities of drugs, especially anthelmintics to children through nationwide annual or biannual mass drug administration largely coordinated through schools. However, a much larger and rapidly growing childhood population in these regions remains untreated and suffering from more than one parasite. Mass drug administration has profound potential for control but is not without considerable challenges and concerns. A principal barrier is funding. Stimulating a research and development pipeline, supporting the necessary clinical trials to refine treatment, in addition to procuring and deploying drugs (and sustaining these supply chains), requires substantial funding and resources that do not presently exist. Limited options for chemotherapy raise concerns about drug resistance developing through overuse, however, satisfactory pharmacoepidemiology and monitoring for drug resistance requires more developed health infrastructures than are generally available. Further, the †Author for correspondence, Graduate Group in Demography, Population Studies Center, University of Pennsylvania, 239 McNeil Building, 3718, Locust Walk, Philadelphia, PA 19104-16298, USA, Tel.: +1 215 898 6441, Fax: +1 215 898 2124, mharhay@pop.upenn.edu. Financial & competing interests disclosurePiero Olliaro is a staff member of the World Health Organization (WHO) and John Horton serves on WHO committees; Michael Harhay is supported by a training grant from the National Institute on Aging, United States National Institutes of Health (NIH) (T32 AG 000177-21). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. No writing assistance was utilized in the production of this manuscript. DisclaimerThe authors alone are responsible for the views expressed in this publication and they do not necessarily represent the decisions, policy or views of the WHO or NIH. NIH Public Access Author ManuscriptExpert Rev Anti Infect Ther. Author manuscript; available in PMC 2010 December 1. Gastrointestinal (GI) protozoa and helminths (Table 1) flourish in settings characterized by warm temperatures, humidity, poor sanitation, dirty water, and substandard and crowded housing. Infection rates are highest...

Factors influencing growth and intestinal parasitic infections in preschoolers attending philanthropic daycare centers in Salvador, Northeast Region of Brazil

“…We used the fecal concentration test which has high reproducibility (i.e., > 95%) and is more sensitive than the commonly used Kato-Katz method 3 . Constraints imposed by the available laboratory facilities meant that it was not possible to use both the sedimentation and flotation procedures and therefore the sedimentation method for parasite examination was chosen based on standard recommendations 12 .…”

“…Therefore, it is not surprising that the risk of intestinal parasitic infection is particularly high in urban and periurban areas in the Northeast Region of Brazil, one of the poorest and most populous regions of this tropical country 2 . Preschool children living in such environments are especially vulnerable to helminth infections with Ascaris lumbricoides (roundworm) and Trichuris trichiura (whipworm) because of the increased activity of these species in potentially infective environments and lack of appropriate sanitary behavior 3 .…”

“…Pathogenic protozoan infections are also common in poor urban settings 3 . Children attending daycare centers are especially vulnerable to Giardia duodenalis and Cryptosporidium sp.…”

Prevalence of Intestinal Parasitic Infection among Rural Area School Children of Lokhim VDC, Nepal

“…Among the soil transmitted helminthes, Ascaris lumbricoides, hookworm and Trichuris trichiura are the most prevalent ones, and are known to infect an estimated one-sixth of the world population. Sub-Saharan African children are known to be the biggest victims of the protozoan and helminthes, followed by Asian, Latin American, and the Caribbean children [5]. The World Health Organization (WHO) estimates that intestinal nematode worms are currently endemic in 130 countries in the world [6], the helminthes that have been commonly found are generally of soilborne type like roundworm (Ascaris lumbricoides), whipworm (Trichuris trichiura) and hookworms (Ancylostoma duodenale and Necator americanus).…”

Malnutrition and the presence of intestinal parasites in children from the poorest municipalities of Mexico

“…Regions with high prevalence of intestinal parasites (i.e. A. lumbricoides or Trichuris trichiura) include Asia, Africa and Latin America [2,4]. The state of Chiapas, Mexico, occupies the first place in multidimensional poverty and has had, for almost a decade (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008), the highest rate of child death due to diarrheal diseases [5].…”