Clinical illness with laboratory confirmation of infection:
- Isolation of Francisella tularensis in an appropriate clinical specimen OR
- Fourfold or greater change in serum antibody titre to F. tularensis antigen OR
- Detection of F. tularensis nucleic acid by polymerase chain reaction (PCR) or sequence-based analysis
Clinical illness with laboratory evidence:
- Detection of F. tularensis in a clinical specimen by fluorescent assay OR
- >1:128 microagglutination titre or >1:160 tube agglutination in a single serum specimen
Definition of clinical illness
Clinical illness is characterized by several distinct forms, including the following:
- ulceroglandular – cutaneous ulcer with regional lymphadenopathy;
- glandular – regional lymphadenopathy with no ulcer;
- oculoglandular – conjunctivitis with preauricular lymphadenopathy;
- oropharyngeal – stomatitis or pharyngitis, or tonsillitis and cervical lymphadenopathy;
- intestinal – intestinal pain, vomiting, and diarrhea;
- pneumonic – primary pleuropulmonary disease; typhoidal – febrile illness without early localizing signs and symptoms.
Clinical diagnosis is supported by evidence or history of a tick or deerfly bite, exposure to the tissues of a mammalian host of Francisella tularensis, or exposure to potentially contaminated water.