ABSTRACT
Present study was performed to determine the effects of physical and chemical agents on infective potential of highly pathogenic avian influenza (HPAI) H5N1 (local strain) virus recently isolated in Pakistan during 2006 outbreak. H5N1 virus having titer 10(8.3) ELD(50)/ml was mixed with sterilized peptone water to get final dilution of 4HA units and then exposed to physical (temperature, pH and ultraviolet light) and chemical (formalin, phenol crystals, iodine crystals, CID 20, virkon-S, zeptin 10%, KEPCIDE 300, KEPCIDE 400, lifebuoy, surf excel and caustic soda) agents. Harvested amnio-allantoic fluid (AAF) from embryonated chicken eggs inoculated with H5N1 treated virus (0.2 ml/egg) was subjected to haemagglutination (HA) and haemagglutination inhibition (HI) tests. H5N1 virus lost infectivity after 30 min at 56 degrees C, after 1 day at 28 degrees C but remained viable for more than 100 days at 4 degrees C. Acidic pH (1, 3) and basic pH (11, 13) were virucidal after 6 h contact time; however virus retained infectivity at pH 5 (18 h), 7 and 9 (more than 24 h). UV light was proved ineffectual in inactivating virus completely even after 60 min. Soap (lifebuoy), detergent (surf excel) and alkali (caustic soda) destroyed infectivity after 5 min at 0.1, 0.2 and 0.3% dilution. All commercially available disinfectants inactivated virus at recommended concentrations. Results of present study would be helpful in implementing bio-security measures at farms/hatcheries levels in the wake of avian influenza virus (AIV) outbreak.
Subject(s)
Chickens/virology , Disease Outbreaks , Disinfectants , Influenza A Virus, H5N1 Subtype , Influenza in Birds , Animals , Chick Embryo , Disinfectants/chemistry , Disinfectants/pharmacology , Hydrogen-Ion Concentration , Influenza A Virus, H5N1 Subtype/drug effects , Influenza A Virus, H5N1 Subtype/pathogenicity , Influenza A Virus, H5N1 Subtype/physiology , Influenza A Virus, H5N1 Subtype/radiation effects , Influenza in Birds/epidemiology , Influenza in Birds/virology , Iodine/chemistry , Iodine/pharmacology , Pakistan/epidemiology , Peroxides , Phenol/chemistry , Phenol/pharmacology , Poultry Diseases/epidemiology , Poultry Diseases/virology , Sulfuric Acids , Temperature , Ultraviolet Rays , Virulence , Virus ReplicationABSTRACT
Normal chicken fecal manure (pH 8.23 and 13.7% moisture) was investigated for infectivity of the avian influenza virus (AIV; H5N1). The manure was divided into three groups; each group was inoculated with AIV at 2.38 x 10(5.25) ELD50. After viral inoculation, the first group was incubated at 25 degrees C. The second group was kept at 40 degrees C, and the last group was exposed to ultraviolet light at 4-5 microw/cm2 at room temperature. After incubation, a 20% suspension of manure was filtered and the filtrates were inoculated into 9-11 day-old embryonated chicken eggs per WHO protocol (2002). The results showed that at 25 degrees C the virus lost its infectivity within 24 hours, and at 40 degrees C within 15 minutes. UV light, however, could not destroy the infectivity of the virus even after exposure for 4 hours.
Subject(s)
Hot Temperature , Influenza A Virus, H5N1 Subtype/pathogenicity , Influenza in Birds/virology , Ultraviolet Rays , Animals , Chick Embryo , Chickens , Influenza A Virus, H5N1 Subtype/radiation effects , Influenza in Birds/transmission , Manure/virologyABSTRACT
In theory, influenza viruses can be transmitted through aerosols, large droplets, or direct contact with secretions (or fomites). These 3 modes are not mutually exclusive. Published findings that support the occurrence of aerosol transmission were reviewed to assess the importance of this mode of transmission. Published evidence indicates that aerosol transmission of influenza can be an important mode of transmission, which has obvious implications for pandemic influenza planning and in particular for recommendations about the use of N95 respirators as part of personal protective equipment.
