QUESTION:
What type of fly would be most common in hospitals?
ANSWER:
I would hate to profile just a single kind of fly, since there are several that deserve mention. To pick on just one kind might lead you into a false sense of security that these others can be ignored. Let’s break it down to either large flies or small flies, and the most important “large” fly is going to be the common House Fly – Musca domestica. It has a wide range of breeding habitats and is possibly the most widespread species of fly, so the opportunity for it to find its way into hospitals is the best. While blow flies will also occur regularly, their presence may be more tied to the presence of something actually inside the hospital that they are breeding in – rotting garbage that is not disposed of quickly or a dead rodent or bird in a wall or attic space. Blow flies just seem less likely than houseflies to wander in from the outside just to look around. House flies have no problem coming in at the slightest opportunity.
With the small flies the ones I seem to have seen most often in hospitals is Phorid flies. They too will breed in a variety of unsanitary situations, including filthy drains like drain flies will and fermenting juices and foods like fruit flies will. These last two flies cannot be ignored as possible hospital pests, especially in dining facilities where spills of juices or fruits and vegetables could occur. But, anyplace water settles and creates decaying organic material the phorid fly will take advantage of, and I have seen a couple of occasions where plumbing problems apparently occurred under slabs, leaking nasty water into the soil beneath the slab, and phorid flies found this opportunity and bred by the thousands.
There are other kinds of flies that will show up now and then too, and the use of UV light traps is an excellent monitoring tool for you. These will attract most kinds of flying insects, particularly when placed where other lighting is minimized and the UV light becomes more attractive. You can check the glue board inside the trap on each visit, and remove it to the office to examine under magnification. By identifying exactly what is captured on the glue you can get a forewarning of possible pest infestations. Different flies indicate different kinds of possible breeding sites, so we might even thank the fly for providing us with a hint that some unsanitary condition exists that should be taken care of in such a sensitive setting.
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