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).

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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.