When is the peak of encephalitic ticks? - briefly
The period of greatest activity for ticks that transmit encephalitis falls in late spring through early summer, generally May – June in temperate zones. Regional climate and latitude can shift this window one to two months later in cooler areas.
When is the peak of encephalitic ticks? - in detail
Encephalitic‑carrying ticks reach their greatest abundance during late spring and early summer. In most of Central and Northern Europe, the activity curve peaks between May and June, coinciding with rising temperatures above 10 °C and increasing humidity that favor questing behaviour. In southern regions, where warmer conditions arrive earlier, the maximum density often occurs in April, while in higher‑latitude areas the peak can shift to July.
Key factors influencing the seasonal surge include:
- Temperature: sustained daytime values of 12–18 °C stimulate metabolism and movement.
- Relative humidity: values above 70 % reduce desiccation risk during host seeking.
- Photoperiod: longer daylight hours trigger developmental transitions in larvae and nymphs.
- Host availability: peak activity of small mammals such as rodents aligns with the tick’s questing period.
Life‑stage distribution varies within the peak window. Nymphs, responsible for the majority of human infections, dominate the early part of the season, whereas adult ticks become more prevalent later, typically in June‑July. Larval activity is generally lower and confined to the earliest warm days.
Regional variations reflect local climate patterns:
- Western Europe (e.g., United Kingdom, France): peak in May–June.
- Central Europe (e.g., Germany, Czech Republic): peak in late May.
- Baltic states and Scandinavia: peak delayed to June–July.
- Mediterranean zones (e.g., Italy, Greece): earlier peak in April–May, sometimes a secondary increase in September.
Monitoring data from public health agencies consistently show that the highest incidence of tick‑borne encephalitis cases follows these activity peaks by 2–4 weeks, reflecting the incubation period after a bite. Preventive measures, such as repellents and clothing protection, are therefore most effective when applied throughout the identified high‑risk months.