Efficacy of Two Peroxygen-Based Disinfectants for Inactivation of Cryptosporidium parvum Oocysts

Abstract

Two commercial peroxygen-based disinfectants containing hydrogen peroxide plus either peracetic acid (Ox-Virin) or silver nitrate (Ox-Agua) were tested for their ability to inactivate Cryptosporidium parvum oocysts. Oocysts were obtained from naturally infected goat kids and exposed to concentrations of 2, 5, and 10% Ox-Virin or 1, 3, and 5% Ox-Agua for 30, 60, and 120 min. In vitro excystation, vital dyes (4,6-diamidino-2-phenylindole and propidium iodide), and infectivity in neonatal BALB/c mice were used to assess the viability and infectivity of control and disinfectant-treated oocysts. Both disinfectants had a deleterious effect on the survival of C. parvum oocysts, since disinfection significantly reduced and in some cases eliminated their viability and infectivity. When in vitro assays were compared with an infectivity assay as indicators of oocyst inactivation, the excystation assay showed 98.6% inactivation after treatment with 10% Ox-Virin for 60 min, while the vital-dye assay showed 95.2% inactivation and the infectivity assay revealed 100% inactivation. Treatment with 3% Ox-Agua for 30 min completely eliminated oocyst infectivity for mice, although we were able to observe only 74.7% inactivation as measured by excystation assays and 24.3% with vital dyes (which proved to be the least reliable method for predicting C. parvum oocyst viability). These findings indicate the potential efficacy of both disinfectants for C. parvum oocysts in agricultural settings where soil, housing, or tools might be contaminated and support the argument that in comparison to the animal infectivity assay, vital-dye and excystation methods overestimate the viability of oocysts following chemical disinfection.

Effect of ivermectin on the integument and dorsoventral muscles of the tick Argas (Persicargas) persicus (Oken) (Ixodoidea: Argasidae)

“…The fowl tick, Argas persicus, is a reservoir and vector of several viral, rickettsial, and spirochaetal pathogens in domestic and wild birds (Hoogstraal 1985). It is also of considerable veterinary importance as parasites of poultry are known to cause weakness, anemia, reduction in egg production and growth, and finally death (Quilez et al 2005). Heavy infestation with this tick may also lead to fowl paralysis (Uspensky 2008).…”

Efficacy of abamectin against the fowl tick, Argas (Persicargas) persicus (Oken, 1818) (Ixodoidea: Argasidae)

“…The fowl tick, Argas persicus, is of considerable veterinary importance as a parasite of poultry and wild birds causing weakness and anemia (Wall and Shearer 1997), reduction in egg production and growth, in addition to their death (Quilez et al 2005). This tick is the vector of fowl spirochaetosis (Wall and Shearer 1997;Shah et al 2006).…”

Efficacy of Dry Mist of Hydrogen Peroxide (DMHP) against Mycobacterium tuberculosis and use of DMHP for Routine Decontamination of Biosafety Level 3 Laboratories

“…It has been recommended in France since September 2006 that this substance not be used for room decontamination, and its production was definitively stopped in January 2007. Thus, research laboratories and hospitals must find other solutions for decontamination; H 2 O 2 provides an alternative to formaldehyde fumigation because of its biological efficacy against various microorganisms (7,8,11,13,17) and its safety (hydrogen peroxide readily decomposes to form water and oxygen).Hydrogen peroxide has already been recommended for the disinfection of a large variety of materials, including dental instruments (18) and bronchoscopes (2). The use of H 2 O 2 vapor (VHP) for the biodecontamination of biological safety cabinets (BSCs), rooms in health care facilities (8), ambulances (1), pharmaceutical facilities, and laboratories (10, 14, 15, 16) has been increasing.…”

“…It has been recommended in France since September 2006 that this substance not be used for room decontamination, and its production was definitively stopped in January 2007. Thus, research laboratories and hospitals must find other solutions for decontamination; H 2 O 2 provides an alternative to formaldehyde fumigation because of its biological efficacy against various microorganisms (7,8,11,13,17) and its safety (hydrogen peroxide readily decomposes to form water and oxygen).…”