Evaluation of poultry house heat treatment as an alternative to post outbreak wet cleaning and disinfection
Date
2020
Authors
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Publisher
University of Delaware
Abstract
Management and control of fast-moving poultry diseases such as highly pathogenic avian influenza virus (HPAIV) infections require a combination of steps including biosecurity, surveillance, quarantine, depopulation, disposal, and cleaning and disinfection. The latter are applied at multiple stages of the process to clean and disinfect personnel, equipment and facilities. Traditionally, post-outbreak cleaning and disinfection of poultry facilities has required a combination of wet and dry cleaning, including pressure washing, rinsing and chemical disinfection treatment. Because of the difficulties associated with cleaning and disinfection, a heat treatment program was used during the 2014 – 2015 HPAI outbreak. To obtain data on the efficiency of such a treatment for a surrogate virus and a bacterial pathogen, poultry litter was placed in modified large colony houses. Steel coupons were inoculated with a lentogenic strain, LaSota, of Newcastle disease virus (NDV) and Salmonella enterica subspecies enterica serovar Enteritidis to test persistence at time points (TP) over 10 days and at different chicken litter depths: surface or 0 cm, 0.6 cm, 2.5 cm, and 10 cm at temperatures between 38 °C to 48 °C. In total, three trials were carried out. Despite solid recovery of control samples for both the treatment and control houses, virus was recovered only from the treatment house at TP-2 and TP-9 in the first trial, at TP-2 in the second trial, and no recovery in the third trial. Viral recovery from the control house occurred at TP-1 for the first trial, TP-1 and TP-4 for the second trial, and TP-1 during the third trial. When compared to the number of overall samples, recovered samples in the treatment house, resulted in 0.07% positive; recovered control samples resulted in 0.12% positive. In the first trial, the Salmonella strain was completely inactivated after four days, likely due to a combination of the heat treatment and ammonia that was emitted by the litter (>100 ppm). In subsequent trials, ammonia concentrations in the treatment house were lower (beginning value for trial 2 was 82 ppm; ending value for trial 3 was 5 ppm). Salmonella inactivation was 2.23 log units after 10 days for trial 2 and 1.49 log units after 10 days for trial 3. Results with respect to litter depth for both biological agents were inconclusive as there was no clear-cut depth effect on each. More studies should be conducted to further evaluate the persistence of each organism at prescribed depths of material, temperature, humidity and time during heat treatment programs.
Description
Keywords
Avian influenza virus, Cleaning and disinfection, Heat treatment, Newcastle disease virus, Poultry diseases, Salmonella spp.