Background: In November 2015, our Infection Control Department was notified of flea infestation in neonatal and pediatric intensive care units (N&PICU) and flea bites among the units healthcare workers (HCWs).
Methods: We conducted an investigation in N&PICU. All sites, equipment, furniture, and unit and personal belongings were thoroughly inspected for fleas. The caught fleas were sent to the Division of Parasitology for further identification. Sources of flea transmission including host animals were searched for. The flea-bitten HCWs were examined for skin lesions and followed-up for development of systemic illnesses, such as severe allergic reactions and typhus.
Results: The flea infestation was found in multiple sites of N&PICU including surfaces of unit belongings, non-medical equipment and walls. We found a couple kittens lying in the space for ventilator and air-conditioner pipes above the ceilings of N&PICU. Given the construction to build a new hospital building near N&PICU, parts of the pipe space were opened up and connected to the outside. This was most-likely the way the cats could get into the area and transmit the fleas. The caught fleas were identified under microscopic examination as Ctenocephalides felis (cat flea) (Figure 1). There were 4 patients and 41 HCWs bitten by the fleas. Single or multiple monomorphic erythematous papules sized 0.5-0.8 cm were found mainly over ankles, lower legs, forearms, neck, and upper back. The interventions to control the fleas included removal of the cats from the area, management of stray cats, closing the opening parts of the pipe space above the unit ceilings, mechanical removal of fleas, washing bedding, blankets and linens in hot water, and 2-hour steam fumigation throughout the units by portable machines (Figure 2) every 8 hours for 4 weeks. The attack rates were 44%, 3% and 0% before and after the 1st and 2nd week of the interventions, respectively (P<0.001). During 1-year follow-up, there had been no reports of additional flea infestation or any flea related systemic illnesses among the bitten patients and HCWs.
Conclusion: Source control and intensive eradication of adult fleas and their eggs by steam fumigation were effective in control of cat flea infestation in the hospital units.
S. Auimsirinukul, None
P. Saichua, None
P. Bunjoungmanee, None