Nasal myiasis in an intensive care unit linked to hospital-wide mouse infestation

A large city hospital experienced an infestation of mice combated in part by broadcasting poisoned baits. Months later there was an invasion of flies into the hospital, and 2 comatose patients in an intensive care unit contracted nasal maggots. Adult flies were trapped and maggots removed from the nares of the second patient. These were identified as the green blowfly (Phaenicia sericata). Recent downsizing of hospital personnel had led to the unintended and unrecognized loss of housekeeping services in the canteen food storage areas. A mouse infestation of the hospital occurred, with the epicenter in the canteen area. This was initially addressed by scattering poisoned bait and using rodent glue boards. The result of such treatment was the presence of numerous mouse carcasses scattered throughout the building attracting the green blowfly. Adult gravid female flies trapped in the new intensive care unit (where mice were not present) laid eggs in the fetid nasal discharge of 2 comatose patients. Live trapping of mice and removal of carcasses led to an abatement of the fly infestation. The cause-and-effect nature of the mouse carcasses and flies was underscored a year later when an outbreak of P sericata occurred in the operating department and was linked to the presence of mouse carcasses on glue boards not removed the previous fall. Hence, the disruption or loss of 1 vital link in hospital organization (in this case, housekeeping support) may lead to an unintended and bizarre outcome.