Table 2.

Case definitions for Lyme disease and chronic arthropod-borne neuropathy (CAN)

	Lyme disease	CAN
History of tick or insect bite initiating illness	Two thirds definitely or possibly bitten. One third do not recall bite.	Usually attribute illness to a preceding bite
Borrelia burgdorferi serology by ELISA and immunoblot	Positive	Negative or non-specific immunoblot bands
Routine haematology and biochemistry investigations	Normal	Normal
Inflammatory markers	Rarely raised	Normal
Early presentation <1 month after bite	Rash + occasional non-specific symptoms	Does not usually present early. Diagnosis is a clinical diagnosis of exclusion.
Later presentation	Specific neurology + occasional non-specific symptoms	Non-specific symptoms, Fatigue, myalgia, cognitive impairment, arthralgia, general paraesthesia, neurology not specific
Clinical examination	Rash or specific neurological deficit: CN palsy, radiculopathy, peripheral neuropathy, meningo-encephalitis, myelitis (arthritis in North America)	Usually normal. Tenderness may be elicited on palpation of muscle groups. Cognitive function and language articulation may be suppressed.
Complete response to defined short antibiotic course	Yes. Recurrence or relapse extremely unusual	No. Recurrence or relapse common.