title: Effect of dilution of stool soluble component on growth and development of Strongyloides stercoralis.
abstract: Dispersion or dilution of stool by water from heavy rainfall may affect Strongyloides stercoralis free-living development producing infective filariform larvae (FL). This study examined effect of water dilution of stool on survival of S. stercoralis free-living development. One g of stool was prepared in water so that its soluble component was diluted sequentially from 1:2 to 1:480. Three dishes were used to compare FL production in three culture conditions: stool suspension, stool sediment deposited in soil, and isolated rhabditiform larvae (RhL) deposited in soil. The fourth dish was for developmental observation of RhL into free-living stages. Numerous FL were generated from undiluted or 1:2 diluted stool and stool sediment placed on soil. However, starting from dilution 1:5, FL production continuously decreased in both stool suspensions and stool sediments placed on soil. RhL isolated from stool dilutions placed on soil gave rise to few FL. Worm mating were seen at 24-30 hours in dilutions 1:20-1:120 only. Highest numbers of FL from indirect free-living cycle were 1/3 of those from control. FL production decreased as stool dilution increased, and reached zero production at 1:160 dilution. Rainfall may disperse or dilute stool so that nutritional supplement for S. stercoralis free-living development is insufficient.
authors.affiliation: Department of Medical Technology, School of Allied Health Sciences and Public Health, Walailak University, Thasala, Nakhon Si Thammarat 80161, Thailand.
authors.forename: Witthaya
authors.initials: W
authors.lastname: Anamnart
authors.affiliation: Department of Parasitology and Research and Diagnostic Center for Emerging Infectious Diseases, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Pewpan Maleewong
authors.initials: PM
authors.lastname: Intapan
authors.affiliation: School of Pharmacy, Walailak University, Thasala, Nakhon Si Thammarat 80161, Thailand.
authors.forename: Attarat
authors.initials: A
authors.lastname: Pattanawongsa
authors.affiliation: Faculty of Medical Technology, Huachiew Chalermprakiet University, Samut Prakan 10540, Thailand.
authors.forename: Pennapa
authors.initials: P
authors.lastname: Chamavit
authors.affiliation: School of Allied Health Sciences and Public Health, Walailak University, Thasala, Nakhon Si Thammarat 80161, Thailand.
authors.forename: Supreecha
authors.initials: S
authors.lastname: Kaewsawat
authors.affiliation: Department of Parasitology and Research and Diagnostic Center for Emerging Infectious Diseases, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Wanchai
authors.initials: W
authors.lastname: Maleewong
mesh_terms: D000818:Animals; D005243:Feces / Q000469:parasitology*; D007814:Larva / Q000254:growth & development; D008018:Life Cycle Stages; D017171:Strongyloides stercoralis / Q000254:growth & development / Q000502:physiology*; D013322:Strongyloidiasis / Q000469:parasitology* / Q000635:transmission*