Utilization of Standard Method Performance Requirements for the Detection of Coxiella burnetii in Environmental Samples.

BACKGROUND: Coxiella burnetii, the causative agent of Q fever, is a long-standing public health problem. Infected animals shed the organism, resulting in aerosol transmission to humans. This organism can potentially be used as a bioterrorism weapon and is on the Department of Health and Human Service Select Agent List. Assay development for detecting C. burnetii in environmental samples has been limited. OBJECTIVE: We describe the use of Standard Method Performance Requirements (SMPR®) 2015.011 to detect Coxiella in air filters and liquids to validate additional environmental samples. METHOD: SMPR 2015.011 was used to validate a real-time polymerase chain reaction (rtPCR) assay developed to detect C. burnetii DNA in powder samples submitted to the public health laboratory for biothreat analysis. RESULTS: Our laboratory developed an assay to detect the icd gene of C. burnetii. The LOD for the assay was 33 gene copies per rtPCR reaction in buffer and 260 in each of the three separate powdered samples. CONCLUSIONS: The SMPR 2015.011 allowed validation of an assay to detect Coxiella nucleic acid in an environmental sample. The assay was sensitive, robust, specific, and able to detect this select agent in powders. HIGHLIGHTS: Development of detection assays for agents that are difficult to culture and have limited validation material available can be problematic for manufacturers. Using the SMPR 2015.011 developed for the detection of Coxiella as well as the SMPR 2016.012 for the detection of Variola, we demonstrated that assays can be appropriately validated using alternative approaches.

Sylvatic typhus associated with flying squirrels (Glaucomys volans) in New York State, United States.

Sylvatic typhus is an infrequent, potentially life-threatening emerging zoonotic disease. In January of 2009, the New York State Department of Health was notified of a familial cluster of two suspected cases. Due to the paucity of typhus cases in New York, epidemiologic and environmental investigations were conducted to establish rickettsial etiology and determine potential sources of infection. Patients presented with symptoms consistent with typhus, and serologic testing of each patient confirmed infection with typhus group rickettsiae. Serologic analysis of blood obtained from southern flying squirrels (Glaucomys volans) captured from the attic crawlspace above an enclosed front porch of the cases' residence indicated evidence of infection with Rickettsia prowazekii, with 100% seroprevalence (n=11). Both patients reported spending significant time on the porch and hearing animal activity above the ceiling prior to onset of illness, implicating these flying squirrels as the likely source of infection.