How many days after a tick bite should blood be tested for encephalitis and borreliosis? - briefly
Blood should be drawn about 2–3 weeks after the bite to detect Lyme‑disease antibodies, and around 7–14 days after the bite (or symptom onset) to detect tick‑borne encephalitis antibodies. These intervals allow reliable serological results for both infections.
How many days after a tick bite should blood be tested for encephalitis and borreliosis? - in detail
The interval between a tick attachment and serological sampling differs for tick‑borne encephalitis (TBE) and Lyme borreliosis because antibody production follows distinct timelines.
Tick‑borne encephalitis
- The virus incubates for 7–14 days before symptoms appear. Detectable IgM antibodies usually emerge 5–7 days after the onset of fever, which corresponds to roughly 12–21 days post‑bite.
- For a reliable result, draw the first serum sample at least 10 days after the bite, preferably when the patient develops fever or neurological signs.
- A convalescent sample collected 2–4 weeks later confirms seroconversion and distinguishes recent infection from previous exposure.
Lyme disease (Borrelia burgdorferi)
- Spirochetes may disseminate within days, but the humoral response is delayed. IgM antibodies typically become detectable 2–4 weeks after the bite; IgG appears after 4–6 weeks.
- An initial test performed before day 14 is likely to be negative and should be interpreted with caution.
- Recommended practice: obtain a baseline specimen at ≥14 days post‑exposure, and repeat testing at ≥30 days if early results are negative but clinical suspicion persists.
Testing modalities
- Enzyme‑linked immunosorbent assay (ELISA) for IgM/IgG is the standard screening method for both infections. Positive ELISA results must be confirmed with a western‑blot (Lyme) or a virus‑neutralization assay (TBE).
- Polymerase chain reaction (PCR) on blood is useful only during the early viremic phase of TBE (first 5 days) and rarely for Lyme, where skin or cerebrospinal fluid specimens are preferred.
Practical summary
- For TBE, schedule the first blood draw no earlier than 10 days after the bite, with a follow‑up sample 2–4 weeks later.
- For Lyme borreliosis, collect the initial serum at least 14 days after exposure; a second sample at 30 days enhances diagnostic certainty.
Adhering to these intervals maximizes the likelihood of detecting pathogen‑specific antibodies and reduces false‑negative results.