Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
2471702 | Veterinary Parasitology | 2008 | 6 Pages |
Cryptosporidium muris oocysts suspended in 200 μl of water were pipetted into plastic microcentrifuge tubes which were stored at 4 °C or frozen at −5 °C for 1, 3, 5, 7, and 10 days and at −20 °C for 1, 3, 5, and 8 h, respectively. Other samples of C. muris oocysts suspended in water were heated in the metal block of a thermal DNA cycler. Block temperatures were set at 5 °C incremental temperatures from 40 to 70 °C. At each high temperature setting microcentrifuge tubes containing C. muris oocysts were exposed for 1 min. Both, frozen and heated oocyst suspensions as well as untreated control oocyst suspensions were then inoculated into each of four ICR mice by gastric intubation. Untreated, freeze-thawed or heated oocysts were considered infectious when oocysts of C. muris were found microscopically in the faeces of mice after inoculation. All inoculated mice that received oocysts frozen at −5 °C for 3, 5, 7, and 10 days and −20 °C for 1, 3, 5, and 8 h had no oocysts in faeces. In contrast, C. muris oocysts frozen at −5 °C for 1 day remained infective for inoculated mice. Our results also indicated that when water containing C. muris oocysts was exposed at a temperature of 55 °C or higher for 1 min, the infectivity of oocysts was lost.