Tularemia (Francisella tularensis) 2017 Case Definition

NOTE: A surveillance case definition is a set of uniform criteria used to define a disease for public health surveillance. Surveillance case definitions enable public health officials to classify and count cases consistently across reporting jurisdictions. Surveillance case definitions are not intended to be used by healthcare providers for making a clinical diagnosis or determining how to meet an individual patient’s health needs.

CSTE Position Statement(s)

16-ID-11

Clinical Criteria

An illness 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
Pneumonic: primary pulmonary disease
Typhoidal: febrile illness without localizing signs and symptoms

Laboratory Criteria For Diagnosis

Supportive

Elevated serum antibody titer(s) to F. tularensis antigen (without documented fourfold or greater change) in a patient with no history of tularemia vaccination, OR
Detection of F. tularensis in a clinical or autopsy specimen by fluorescent assay, OR
Detection of F. tularensis in a clinical or autopsy specimen by a polymerase chain reaction (PCR)

Confirmatory

Isolation of F. tularensis in a clinical or autopsy specimen, OR
Fourfold or greater change in serum antibody titer to F. tularensis antigen between acute and convalescent specimens

Epidemiologic Linkage

Clinical diagnosis is supported by evidence or history of a tick or deerfly bite, exposure to tissues of a mammalian host of F. tularensis, including via an animal bite, or exposure to potentially contaminated water.

Criteria to Distinguish a New Case from an Existing Case

Serial or subsequent cases of tularemia experienced by one individual should only be counted if there is an additional epidemiologically compatible exposure and new onset of symptoms. Because the duration of antibodies to F. tularensis is not known, mere presence of antibodies without a clinically-compatible illness AND an epidemiologically compatible exposure within 12 months of onset may not indicate a new infection, especially among persons who live in endemic areas.

Case Classification

Probable

A clinically-compatible case with supportive laboratory evidence.

Confirmed

A clinically-compatible case with confirmatory laboratory evidence.

Related Case Definition(s)

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National Notifiable Diseases Surveillance System (NNDSS)