title: Dramatic decrease in prevalence of soil-transmitted helminths and new insights into intestinal protozoa in children living in the Chaco region, Bolivia.
abstract: We assessed the prevalence of intestinal parasites among 268 2-12-year-old children living in rural areas, small villages, and semi-urban areas of the Chaco region, south-eastern Bolivia. The overall parasitism was 69%. Only protozoa, helminths, or co-infections were observed in 89.2%, 5.9%, or 4.9% of the positive children, respectively. A significant progressive increase in overall parasite prevalence was found when passing from rural areas to small villages and semi-urban areas. The most commonly found species were Entamoeba coli (38.4%), Giardia intestinalis (37.7%), and Blastocystis spp. (16%). Hymenolepis nana was the most prevalent helminth (5.6%), followed by Ascaris lumbricoides and hookworms (1.5% and 0.4%) evidenced only in rural areas and in villages. Molecular diagnostics identified Blastocystis subtypes 9 and 2, and 5 infections by Entamoeba histolytica and 4 by Entamoeba dispar. The dramatic decrease in prevalence of soil-transmitted helminths with respect to that observed about 20 years ago (> 40%) evidences the success of the preventive chemotherapy intervention implemented in 1986. Health education and improved sanitation should be intensified to control protozoan infections.
authors.forename: Fabio
authors.initials: F
authors.lastname: Macchioni
authors.forename: Higinio
authors.initials: H
authors.lastname: Segundo
authors.forename: Simona
authors.initials: S
authors.lastname: Gabrielli
authors.forename: Valentina
authors.initials: V
authors.lastname: Totino
authors.forename: Patricia Rojas
authors.initials: PR
authors.lastname: Gonzales
authors.forename: Esteban
authors.initials: E
authors.lastname: Salazar
authors.forename: Ricardo
authors.initials: R
authors.lastname: Bozo
authors.forename: Alessandro
authors.initials: A
authors.lastname: Bartoloni
authors.forename: Gabriella
authors.initials: G
authors.lastname: Cancrini
mesh_terms: D000818:Animals; D001838:Bolivia / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D060085:Coinfection; D005243:Feces / Q000469:parasitology; D005260:Female; D006373:Helminthiasis / Q000453:epidemiology* / Q000469:parasitology / Q000517:prevention & control / Q000635:transmission; D006376:Helminths / Q000502:physiology*; D006801:Humans; D007411:Intestinal Diseases, Parasitic / Q000453:epidemiology* / Q000469:parasitology / Q000517:prevention & control / Q000635:transmission; D008297:Male; D015995:Prevalence; D011528:Protozoan Infections / Q000453:epidemiology* / Q000469:parasitology / Q000517:prevention & control / Q000635:transmission; D012499:Sanitation; D012987:Soil / Q000469:parasitology*
chemical_list: D012987:Soil