title: Restoration of hookworm egg development after prolonged storage in stool suspension.
abstract: Hookworm infection is still prevalent in southern Thailand despite control measures. Hookworm eggs submerged for an extended period under water from rainfall or in latrines may not survive, but they may recover their ability to develop into infective larvae when exposed to atmospheric air. This study examined the survival of the hookworm eggs in stool suspension and the restoration of development capability after prolonged storage. In stool mass, eggs developed normally and yielded infective filariform larvae (FL) in 7 days. On the contrary, in 1:10 stool suspension, hookworm eggs were found to remain at the 4-8 cell stage; degenerated eggs were observed after 15 days of storage, and the number of degenerated eggs reached 80 % on day 30. Aeration of the suspension, or transferring to a Petri dish or agar plate, restored the capacity of eggs stored for up to 15 days to develop into FL; thereafter, the capacity declined sharply. Retardation of egg development under water or in stool suspension may be due to a lack of atmospheric air. Use of "night soil" from latrines as fertilizer may be one factor in maintaining hookworm transmission, as worm eggs can undergo normal development upon exposure to atmospheric air.
authors.affiliation: School of Medicine, Walailak University, Thasala, Nakhon Si Thammarat, Thailand.
authors.forename: Prasit
authors.initials: P
authors.lastname: Na-Ek
authors.affiliation: Department of Parasitology and Research and Diagnostic Center for Emerging Infectious Diseases, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Oranuch
authors.initials: O
authors.lastname: Sanpool
authors.affiliation: Department of Parasitology and Research and Diagnostic Center for Emerging Infectious Diseases, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Jurairat
authors.initials: J
authors.lastname: Jongthawin
authors.affiliation: School of Allied Health Sciences and Public Health, Walailak University, Thasala, Nakhon Si Thammarat, 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, Thailand.
authors.forename: Pewpan M
authors.initials: PM
authors.lastname: Intapan
authors.affiliation: Department of Parasitology, Faculty of Medical Technology, Huachiew Chalermprakiet University, Samut Prakan, Thailand.
authors.forename: Pennapa
authors.initials: P
authors.lastname: Chamavit
authors.affiliation: Department of Parasitology and Research and Diagnostic Center for Emerging Infectious Diseases, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand. wanch_ma@kku.ac.th.
authors.forename: Wanchai
authors.initials: W
authors.lastname: Maleewong
mesh_terms: D000723:Ancylostomatoidea / Q000254:growth & development* / Q000472:pathogenicity; D000818:Animals; D005243:Feces / Q000469:parasitology*; D005260:Female; D006725:Hookworm Infections / Q000453:epidemiology / Q000469:parasitology* / Q000635:transmission; D006801:Humans; D007814:Larva; D009331:Necator / Q000254:growth & development* / Q000472:pathogenicity; D009332:Necatoriasis / Q000453:epidemiology / Q000469:parasitology* / Q000635:transmission; D010063:Ovum / Q000254:growth & development; D011309:Preservation, Biological / Q000379:methods* / Q000592:standards; D015995:Prevalence; D012987:Soil / Q000469:parasitology; D013535:Suspensions; D013785:Thailand / Q000453:epidemiology; D014867:Water / Q000469:parasitology
chemical_list: D012987:Soil; D013535:Suspensions; D014867:Water
keywords: Development capability; Environmental conditions; Hookworm; Necator americanus