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Rats and Humans
I contributed to an article "Invasion of Rats Sparks Fears for Residents' Health" by Rob Westall (http://www.thisissouthwales.co.uk/) on 04 May 2007. This concerned sightings (one has to say that an awful lot go unsighted) of rats in Brynmill Swansea. I pointed out that current estimates were that there were about 60 million Brown rats (Rattus norvegicus) in the UK (one per person). The article implied that I believed that global warming was a factor in their population increase. This may be the case but, at present, all we can really say with any certainty is that the recent 'crop' of mild winters may have increased the survival of potential breeders in their colonies (and rats are very productive). The increases in rat numbers in such locations are probably more closely associated with available food resources. Brown rats are flexible omnivores and will feed on garbage, bird food, garden waste, mice, young chicks in their nests etc. The article emphasised that the main potential health risk of these rodents to humans is the spirochete that they may release in their urine and can cause Leptospirosis or Weil's disease. The agent may be picked up via lesions in the skin from fresh water, soil or vegetation. Bubonic plague (even if it actually involved rats- this has been debated) is transmitted by the bites of fleas from an entirely different kind of rat (the Black or Ship rat).
I contributed to an article "Invasion of Rats Sparks Fears for Residents' Health" by Rob Westall (http://www.thisissouthwales.co.uk/) on 04 May 2007. This concerned sightings (one has to say that an awful lot go unsighted) of rats in Brynmill Swansea. I pointed out that current estimates were that there were about 60 million Brown rats (Rattus norvegicus) in the UK (one per person). The article implied that I believed that global warming was a factor in their population increase. This may be the case but, at present, all we can really say with any certainty is that the recent 'crop' of mild winters may have increased the survival of potential breeders in their colonies (and rats are very productive). The increases in rat numbers in such locations are probably more closely associated with available food resources. Brown rats are flexible omnivores and will feed on garbage, bird food, garden waste, mice, young chicks in their nests etc. The article emphasised that the main potential health risk of these rodents to humans is the spirochete that they may release in their urine and can cause Leptospirosis or Weil's disease. The agent may be picked up via lesions in the skin from fresh water, soil or vegetation. Bubonic plague (even if it actually involved rats- this has been debated) is transmitted by the bites of fleas from an entirely different kind of rat (the Black or Ship rat).
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