Water-Borne Outbreak of Oropharyngeal and Glandular Tularemia in Georgia: Investigation and Follow-up

Background: In November 2006, an outbreak of water-borne tularemia occurred in an eastern region in the Republic of Georgia. Outbreak investigation revealed 26 cases: 21 oropharyngeal and 5 glandular tularemia cases. Methods: The presentation of the index case triggered an outbreak investigation involving the collection of clinical/epidemiological data, application of tularine skin test, and laboratory confirmation of the possible cases using the tube agglutination test and polymerase chain reaction (PCR) testing. Serology results were verified by enzyme-Linked immunosorbent assay (ELISA) and Western blot. A case-control study along with follow-up was conducted 4 months after the index case presentation. Results: Exudative pharyngitis, predominantly laterocervical adenitis, fever, and headache were the most prevalent clinical signs/symptoms observed. Depressed mood, concentration difficulties, and steep disturbance were also detected. Bubo aspirates tested by PCR were positive in 4/4 cases and pharyngeal swabs also tested by PCR were positive in 2/3 cases. Francisella tularensis was isolated from the water samples. Comparison of the cases and controls did not reveal any statistically significant risk factors. A follow-up investigation revealed cases with protracted symptoms of fatigue, headache, and steep disturbance. Additionally, 8/26 cases still had cervical adenopathy of prominent size. A delay in diagnosis was associated with persistent lymphadenopathy on follow-up examination (p = 0.05). Conclusion: We observed unique features of persistent neuropsychiatric symptoms and lymphadenopathy 5 months after tularemia infection which were associated with delayed diagnosis and the tack of prompt response to therapy. This outbreak of oropharyngeal tularemia emphasizes the importance of a rapid diagnostic and investigative response to tularemia. This type of response can prevent ongoing exposure, as welt as provide expeditious treatment to mitigate persistent symptoms.