The animal’s behaviour may change especially toward the end, they become lethargic and more approachable. The virus appears to be endemic amongst the UK grey squirrel population and its effects, if any, on this species are unclear.
Nearly all grey squirrels with pox antibodies do not display any outward symptoms. Pox-type viruses are fairly resilient and will survive outside the host for a considerable time if the conditions are favourable.
Dry weather may mean the virus remains viable for over a month. Wet conditions will reduce its viable period considerably.
Outside the host the virus can be killed by good hygiene procedures using anti-viral veterinary disinfectants. Once in a population of squirrels the virus spreads very quickly, isolated woodlands can quickly lose all their red squirrels.
The Northern Ireland Squirrel Forum has developed a Standard Operating Procedure (SOP) document that explains the best procedures for cleaning and disinfecting traps and squirrel feeders.
There is no known risk to humans from squirrel pox but washing your hands after handling any animal is advisable as other pathogens may potentially cause you harm.
Red squirrels seem particularly susceptible to a range of other diseases, this is probably due to the fact they are in relatively isolated populations, geographically separated from neighbouring populations, which in turn probably restricts the local genetic diversity.
There is certainly a risk that should an infection get into a isolated population that those squirrels can be severely reduced in number and there are not enough new squirrels from satellite populations to back fill the losses.
The spread of most of these diseases rely on close contact between animals, therefore where squirrels are attracted to artificial feeding sites there is an increased risk of pathogens coming into contact the visiting animals. Where feeders are used by squirrels frequent disinfection as detailed above can reduce disease spread.