| | In a press release dated July 11th, USPOULTRY presented the results of a series of experiments conducted by Dr. Haroldo Toro of Auburn University (Project number BRU 004). The study was conducted using funds approved for emergency research related to the outbreak of highly pathogenic Avian Influenza in the spring of last year. The study to inactivate Avian Influenza virus in feed is the first of a series of projects completed using fast-track funding. | | |
The series of four trials was conducted to evaluate the effectiveness of Termin-8® on inactivation of an H5 strain of LPAI virus added to feed under controlled experimental conditions. The secondary objective was to demonstrate the residual effect of Termin-8® on inactivation of AIV in feed.
The model used by Dr. Toro comprised contamination of a layer feed with a low- pathogenic AIV, strain H5N9 isolated from turkeys in Wisconsin in 1968. The presence of virus in feed was identified by an extraction process followed by treatment with antibiotic to destroy bacteria and then centrifugation and filtration. The presence of influenza virus was identified by inoculating processed supernatant into embryonated specific pathogen-free eggs with subsequent demonstration of viral RNA in allantoic fluid using RT-PCR.
In the first experiment to determine effectiveness of Termin-8® it was demonstrated that the concentration of virus was reduced after 4 hours following inoculation of feed previously treated with Termin-8® at the rate of 2 pounds per ton. In a second trial to evaluate survival of AIV in either feed or corn, it was demonstrated that relatively high levels of virus were maintained following inoculation for 24 hours with a decline to undetectable levels after 48 hours.
Termin-8® effectively reduced the concentration of AIV in feed within one hour by a level of 6 LOG10 compared to untreated feed. After six hours there was a significant difference in concentration of AIV between the treatment and control with the feed devoid of Termin-8® showing levels ranging from 4 to 8 LOG10 per gram of feed.
The residual effect of Termin-8® was evaluated by adding the compound to feed seven days before inoculation with AIV. Control and treated feed were assayed for the presence of AIV after six hours. Concentration of virus in the untreated control feed ranged from 2 to 8 LOG10 program compared to undetectable level in the feed treated with Termin-8®.
The series of trials conducted by Dr. Toro demonstrated the effectiveness of Termin-8® in suppressing AIV in feed. In addition the compound was effective for at least seven days after being added to feed.
Although feed is not regarded as a primary route of introducing AIV onto farms, a coordinated program of protection should include suppression of possible transmission associated with delivering contaminated feed to susceptible flocks.