Effectiveness of Four Disinfectants against Ebola Virus on Different Materials

Abstract

The West Africa Ebola virus (EBOV) outbreak has highlighted the need for effective disinfectants capable of reducing viral load in a range of sample types, equipment and settings. Although chlorine-based products are widely used, they can also be damaging to equipment or apparatus that needs continuous use such as aircraft use for transportation of infected people. Two aircraft cleaning solutions were assessed alongside two common laboratory disinfectants in a contact kill assay with EBOV on two aircraft relevant materials representative of a porous and non-porous surface. A decimal log reduction of viral titre of 4 is required for a disinfectant to be deemed effective and two of the disinfectants fulfilled this criteria under the conditions tested. One product, Ardrox 6092, was found to perform similarly to sodium hypochlorite, but as it does not have the corrosive properties of sodium hypochlorite, it could be an alternative disinfectant solution to be used for decontamination of EBOV on sensitive apparatus.

Keywords: Ebola virus; decontamination; disinfection; inactivation; safety; sodium hypochlorite.

Figure 1

Recovery of Ebola virus (EBOV)-Ecran from different test surfaces. EBOV-Ecran or tissue culture media (TCM) was deposited onto 2 different coupon types, or directly onto a sterile 6-well cell culture plate (no coupon), before being recovered into 2 mL TCM by vortexing for 10 s. Samples were washed up to three times prior to enumeration. The titre of EBOV-Ecran (in TCID₅₀/mL) recovered from 3 replicate tests is shown (±SEM). All TCM samples were negative for viable EBOV-Ecran. TCID₅₀: 50% tissue culture infectious dose.

Figure 2

Reduction in EBOV-Ecran titre on different test surfaces after contact with four different disinfectants. EBOV-Ecran was deposited onto three surfaces and an equal volume of disinfectant or TCM was added for a contact time of 10 min (n = 3). When TCM was added to virus in place of disinfectant, high titres of EBOV-Ecran were recovered (Table 2; 1.5 × 10⁵ TCID₅₀/mL from aluminium; 2.2 × 10³ TCID₅₀/mL from strapping and 1.1 × 10⁵ TCID₅₀/mL from no coupon) and these values served as the positive control against which disinfectants were assessed. The reduction in log₁₀ titre was determined as the difference between the mean log₁₀-titre with no disinfection (TCM only) and the mean log₁₀-titre for each disinfectant on aluminium coupons (grey bars), strapping coupons (black bars) or directly onto a sterile 6-well cell culture plate (no coupon, white bars). The British standard minimum requirement is a 4-log₁₀ reduction (dashed line).