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Emergency Livestock Disposal Home
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Project in Detail
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Mortality Composting
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PRELIMINARY RESULTS
Biosecurity
Virus Survival -Newcastle Disease Virus
The data charted above are exemplary of preliminary virus survival data obtained during cool and warm weather trials in April (trial #3) and June (trial # 4) of 2003.
These data for a vaccine strain of Newcastle Disease (NDV), show that survival times are typically lower for samples contained in dialysis cassettes than for samples in cryogenic vials. These results seem logical, as viruses in the cryogenic vials are exposed only to heat from the composting process, while viruses in the dialysis cassettes are exposed not only to the heat of composting, but to drying, changes in pH, and the effects of gases, such as ammonia, that are released during decomposition of organic matter.
During cool weather (trial #3), the most rapid inactivation occurred in the silage trial, which typically produces high temperatures much more quickly than the drier and more permeable cornstalk and leaf much (used only in trial #3) cover materials.
During warmer weather (trial # 4) virus inactivation within the cornstalk test unit was as rapid, or more so, than in the silage or hay/manure test units.\
Data for the vaccine strain of avian encephalomyelitis are still being assessed and are not available at this time.
Virus
Containment
Preliminary data indicate that windrow composting, using at least 18-inches of cover material over infected surfaces, is reasonably effective at retaining viruses against transport by wind, insects, and other natural processes or vectors.
Of 48 caged pathogen-free birds stationed around trial #'s 1 and 4 (late summer and fall of 2002, and summer of 2003) none have tested positive for NDV antibodies during the 10-12 week blood sampling and testing period.
Of the same 48 birds, one tested positive for avian encephalomyelitis antibodies during trial # 4.
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In Brief
1. Newcastle Disease Virus survival times are much shorter when viruses are exposed to the full range of environmental conditions (not just heat) that are present within composting systems.
2. Vaccine strains of Newcastle Disease Virus contained in dialysis cassettes survived fewer than 8 days during cool (late April) weather, and fewer than 3 days during warm (June) weather.
3. Silage test units offered the shortest virus survival times during cool weather. During warm weather, the type of cover material did not greatly affect virus survival time.
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