Comparison of assays for Cryptosporidium parvum oocysts viability after chemical disinfection.
In vitro excystation, vital dyes (4', 6-diamidino-2-phenylindole (DAPI) and propidium iodide (PI), and infectivity in neonatal CD-1 mice were used to assess the viability of Cryptosporidium parvum oocysts after chemical disinfection. In vitro excystation and DAPI/PI staining provided similar estimates of viability in bench-scale experiments, but both of these methods significantly overestimated the viability when compared with infectivity (Pr < or = 0.01). Infectivity was the most reliable measure of the viability of C. parvum oocysts following chemical disinfection.
Black
E K
EK
Department of Civil Engineering, University of Alberta, Edmonton, Canada.
Finch
G R
GR
Taghi-Kilani
R
R
Belosevic
M
M
D000818:Animals; D000831:Animals, Newborn; D016785:Cryptosporidium parvum / Q000302:isolation & purification / Q000472:pathogenicity / Q000502:physiology*; D004203:Disinfection; D005456:Fluorescent Dyes; D007211:Indoles; D051379:Mice; D011419:Propidium
D005456:Fluorescent Dyes; D007211:Indoles; D011419:Propidium; C007293:DAPI