Cluster of Pneumonic Tularemia Following a Community Clean-up Event

BACKGROUND: June 10, 2014, the North Dakota Department of Health was notified that four individuals from Benson County were hospitalized with an unknown respiratory illness, a few days after working together providing community clean-up.

METHODS:   A public health investigation was launched to determine the etiologic agent, activities preceding infection and if others were similarly sick within the community. No additional cases were identified except one suspect fifth case that took part in some of the clean-up activities. This case had illness onset two weeks after the initial cases and did not develop similar respiratory illness so it is unclear if the individual was related to the outbreak cluster.

RESULTS:   Patients initially presented with gastrointestinal illness and progressed to include fever, cough, chills, shortness of breath, fatigue and malaise. They developed pneumonia and three had pleural effusions. Bacterial, viral and mycotic pathogen testing was performed. Three of the four patients were serologically-confirmed tularemia infections of which one also had pleural fluid positive for F. tularensis via PCR. Convalescent specimens were unable to be obtained for the fourth patient and suspect fifth case. The cases collected items left at the curb from residential areas during a city clean-up event. They reported removing items such as furniture, clothing, appliances, wet newspaper, old food, and items soaked in cat urine, dog feces and mouse droppings. None of the cases reported tick bites, contact with sick or dead animals, hunting, or ingesting untreated water.

CONCLUSIONS:   Patients were interviewed multiple times but due to a variety of circumstances complete exposure histories were not able to be collected. These cases were all independent contractors that had no PPE, no professional training and no additional links to each other beyond the community clean-up work. It is theorized that exposure may have occurred through inhalation of contaminated dust or other material, vectors such as deer or horseflies, or environmental contamination such as dead rodents, rabbits or cats during the community clean-up.