Submitted to: Avian Diseases
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/4/2002
Publication Date: 9/1/2003
Citation: Suarez, D.L., Spackman, E., Senne, D., Bulaga, L., Welsch, A.C., Froberg, K. 2003. The effect of various disinfectants on detection of avian influenza virus by real time rt-pcr. Avian Diseases. 47:1091-1095, 2003. Interpretive Summary: Avian influenza virus can cause serious disease in chickens and turkeys. The virus comes in many different subtypes from H1 to H15, but infections with the H5 and H7 influenza subtypes are potentially the worst, and outbreaks of these two subtypes often results in trade embargoes from other countries. Therefore eradication of influenza viruses is critical to limit the economic damage. As part of any control effort, disinfectants are used to kill the virus to limit its spread. For influenza, many types of disinfectants are effective at killing the virus. Recently a new rapid diagnostic test was developed for the detection of avian influenza called real time RT-PCR. This test detects the genetic material of the virus, and potentially can identify both live and dead virus. It was therefore important to know how if different commonly used disinfectants would kill the influenza virus, but not affect the viral genetic material so that it could still be detected by this new test. This paper describes the comparison of different commonly used disinfectants to kill influenza and also block viral detection by the real-time RT-PCR test. Five different disinfectants were used and it was demonstrated that three of the disinfectants did kill the virus, but the dead virus was still detected by the real-time RT-PCR test. Two of the disinfectants, at high doses, not only killed the virus, but blocked its detection by real-time RT-PCR. The real-time RT-PCR test is a valuable new tool, but caution needs to be used for testing samples from the environment where disinfectants have been used.
Technical Abstract: An avian influenza real time RT-PCR (RRT-PCR) test was previously shown to be a rapid and sensitive method to identify avian influenza virus-infected birds in live bird markets (LBMs). The test can also be used to identify avian influenza virus (AIV) from environmental samples. Consequently, the use of RRT-PCR was being considered as a component of the influenza eradication program in the LBMs to assure that each market was properly cleaned and disinfected before allowing the markets to be restocked. However, the RRT-PCR test can't differentiate between live and inactivated virus, particularly in environmental samples where the RRT-PCR test potentially could amplify virus that had been inactivated by commonly used disinfectants, resulting in a false positive test result. To determine if this was a valid concern, a study was conducted in three New Jersey LBMs that were previously shown to be positive for the H7N2 AIV. Environmental samples were collected from all three markets following thorough cleaning and disinfection with a phenolic disinfectant. Influenza virus RNA was detected in at least one environmental sample from two of the three markets when tested by RRT-PCR, however all samples were negative by virus isolation using the standard egg inoculation procedure. As a result of these findings, laboratory experiments were designed to evaluate several commonly used disinfectants for their ability to inactivate influenza as well as disrupt the RNA so that it could not be detected by the RRT-PCR test. Five disinfectants were tested: Tek-trol and One-Stroke Environ, phenolic disinfectants; Lysol No-rinse Sanitizer, a quaternary ammonia compound; Virkon-S, a peroxygen compound; and household bleach, a chlorine compound. All five disinfectants were effective at inactivating AIV at the recommended concentrations, but AIV RNA in samples inactivated with phenolic and quaternary ammonia compounds could still be detected by RRT-PCR. The peroxygen and chlorine compounds were effective at some concentrations for both inactivating virus and preventing amplification by RRT-PCR. Therefore, the RRT-PCR test can potentially be used to assure proper cleaning and disinfection when certain disinfectants are used.