Early response can
be defined as all actions that would be targeted at rapid and effective
containment of, and then possibly elimination of, an emergency disease
outbreak, with the objective of preventing it from spreading and becoming an
uncontrollable epizootic. There are three broad control options for responding
to emergency disease detection; the option chosen for any particular disease
will depend on many different factors associated with the detection scenario.
Some cases may require testing a combination of these options:
- Eradication. Initial eradication of disease
with eventual total elimination of the pathogen from the country or affected
population, including sub-clinical infections if they occur. This is the
highest level of response but may not always be possible, especially where the
disease was well-established prior to the initial detection (i.e. where early
detection has essentially failed), intermediate or carrier hosts are unknown,
or the source of the infection is unknown (or related to an uncontrollable,
ongoing, unrelated human activity such as recreational water use or commercial
shipping).
- Containment. Containment of the disease and
pathogen within specified zones with controls in place around infected zones to
prevent spread to uninfected populations within the country or straddling
neighbouring borders.
- Mitigation. Reduction of the impacts of the
pathogen by implementing control measures at the farm, or affected population,
level that reduce the occurrence and severity of disease. These measures focus
on stocks within the infected zone, and concentrate on long-term circumvention
of disease losses, either through development of treatments (vaccines,
antibiotics as appropriate) or husbandry techniques (selection of resistant
broodstock, variation of stocking/harvest times). These measures are based on
failed eradication attempts or epidemiological risk assessments indicating that
eradication efforts are unfeasible or impractical.
