If you know your bugs you know that Blattella germanica and Periplaneta americana are cockroaches. They aren't the only cockroach species. In fact there are an estimated 4000 different kinds of cockroach, many of them living in fields, forests or jungles. Unless they are living in your hospital's Intensive Care Unit:
Ectobius vittiventris (Costa) is a field-dwelling cockroach and 1 of 4,000 species worldwide. We describe a cockroach infestation of an intensive care unit (ICU).[snip]
The University of Geneva Hospitals are a 2,200-bed tertiary healthcare center. The 18-bed medical ICU is located on the ground floor next to an outdoor recreational area and admits ≈1,400 patients/year. Smoking inside hospital buildings by patients and healthcare workers (HCWs) is strictly prohibited. On August 25, 2006, ≈30 cockroaches were observed in the ICU hiding inside oxygen masks, moving around on the light panels below the ceilings, or dropping onto intubated patients during the night. (Uçkay I et al. "Cockroaches (Ectobius vittiventris) in an intensive care unit, Switzerland" [letter]. Emerg Infect Dis. 2009 Mar; [Epub ahead of print, cites omitted]
Yikes. E. vittiventris looks a lot like Blattella germanica, the German cockroach most people think of when the word cockroach is uttered (Periplaneta americana is much larger and often called a "waterbug" or "Palmetto bug"). Looks like it but isn't the same. For one thing the German cockroach is nocturnal (you see them sucrry for cover when you turn on the kitchen light). E. vittiventris is up and about by daylight. The German cockroach lives with people, and breeds in their domiciles. E. vittiventris lives and breeds outside. The German cockroach can't fly, but E. vittiventris can. So what was E. vittiventris doing in the ICU and how did they get there? An outbreak investigation was undertaken:
The investigation showed that despite verbal recommendations and being repeatedly forbidden to do so, HCWs had opened the windows secretly with screwdrivers so that they could smoke during night shifts. The infestation was halted within 3 days after information regarding the infestation was provided to HCWs and all windows were bolted shut. In contrast to measures required to deal with a reported infestation in a neonatal ICU, no other measures such as use of insecticides, review of the air circulation system, or changes in architectural structures were necessary to stop the infestation reported here.
It's clear that you don't want cockroaches of any species scurrying around your ICU. But a scan of the literature turns up very little in the way of documented disease outbreaks traced definitively to cockroaches. Cockroaches aren't especially clean and you can find lots of pathogens in them. When I first started teaching environmental health 30 years ago I had a microbiologist in my class. One week we were touring the cafeteria of a large inner city hospital and we saw a number of cockroaches. We captured them and my student ground them up in a blender and plated out the resulting homogenate. As expected, there were a lot of microbes, including enteric pathogens like E. coli and Salmonella. But do they cause disease? That's much harder to prove.
E. vittiventris also can carry pathogens but has never been implicated in disease transmission. But then the usual commensal cockroaches haven't either, except on rare occasions. What's interesting about this case is that complete control was achieved without any insecticides. Understanding the ecology of the species enabled eradication by the simple expedient of bolting the windows closed.
Mrs. R., on the other hand, had a different response when she found a water bug in our lodgings when we were vacationing down South. It involved a shotgun and a nuclear weapon.
Medicine & Health
Comments
Cockroaches not implicated in disease? Brr! They give me the heebie-jeebies every time I see them.
Why don't they just put screens on the windows? Fresh air is nice. And maybe relax the smoking policy a bit - let them go outside for a light the way we do here?
Posted by: george.w | April 4, 2009 9:02 AM
First year of grad school, we had a lot of contamination in the tissue culture lab. The TC lab was in a decrepit part of the basement of the building, and early-morning students regularly had to shoo cockroaches away. Except you couldn't squash them, because then the pregnant females' eggs would be squooshed all over your shoes and you'd track the eggs all over the building to hatch. You had to scoop them up in Petri dishes and chuck them outside. We attributed the contamination to nocturnal insect visits, and asked if we could possibly move the TC lab. To, you know, anywhere but the dungeon.
My adviser, who didn't come in till 9am, and whose office was on the third floor, believed none of it. He shouted at all of us for having poor aseptic technique and failing to take responsibility for our stupidity.
Next morning, I came in at 7am to find him perched over a floor drain with a giant bottle of bleach, and a dead cockroach smashed on the lab bench. Seems he had come in early to try to catch us in the act of bad technique, and instead was unpleasantly surprised to find cockroaches all over the benches and tissue culture hoods.
Still, I pity Gregor Samsa.
Posted by: Lora | April 4, 2009 5:25 PM
It's weird. I'm terribly squirmy and grossed out by crawling bugs (ants, spiders, cockroaches), but the flying insects (flies, mosquitoes, fleas, moths) don't really bother me. I've often thought that it should be the opposite, given how much devastation flying insects and the pathogens they carry have wreaked on humanity. I'm not a biologist, but as far as I know, crawling insects don't have even close to the same disease risk as the flying ones.
Posted by: samantha | April 5, 2009 3:51 AM
In the 70s, when the residents and interns in NYC's hospitals went on strike, a few of the demands had to do with better housekeeping. I asked one of the residents about them. He said he'd lost a patient because she'd had a roach in her oxygen tube.
Posted by: Molly, NYC | April 5, 2009 4:39 AM
Lora, too bad he found out that way. It would have been more gratifying to capture a whole bunch of them and release them in HIS office.
Posted by: Gindy | April 5, 2009 9:35 AM
Any comments on this story in the NYTimes on roaches being a significant cause of childhood asthma in inner cities?
Posted by: Stagyar zil Doggo | April 9, 2009 6:21 PM
Doggo: No comments other than the fact that cockroach frass is a well known cause of asthma. The work you refer to, if it is what I saw, involves trying to figure out exactly what it is in cockroach frass that is doing it and involves a good animal model for it.
Posted by: revere
| April 9, 2009 9:20 PM
Another NYtimes article about asthma:
http://www.nytimes.com/2009/01/27/health/27brod.html?scp=1&sq=Baby%20eats%20a%20little%20dirt&st=cse
Its hypothesis about asthma is that immunity system had not been programmed well due to when a person in baby stage had not been challenged enough by worm. The author- Jane's advice is to let the child to have a dog to play with.
Posted by: paiwan | April 9, 2009 9:51 PM