Why is tick-borne encephalitis increasing? A review of the key factors causing the increasing incidence of human TBE in Sweden

Table 1 Infestation of mammals by larvae, nymphs and adult females of Ixodes ricinus

	Larvae	Nymphs	Females	L:N:F ratio	Range (all tick stages)	Number of hosts examined
Myodes glareolus*	34	0.9	0	38:1:0	1-219	106
*Apodemus* spp.*	60	1.5	0	40:1:0	4–451	50
Capreolus capreolus*	265	93	30	2.8:1:0.3	428–2072	37
*Lepus timidus* *	630	255	13	2.5:1.0:0.05	458–1725	8
Lepus timidus**	412	53	6	7.8:1:0.1	87-2374	15

Larvae, Mean no. larvae; Nymphs, Mean no. nymphs; Females, Mean no. adult I. ricinus females; L:N:F, Larvae : Nymphs : Females; *, from provinces of Uppland and Södermanland on the Swedish mainland; **, from Gotska Sandön, which is an isolated island in the Baltic Sea.
Data from Tälleklint & Jaenson [22].

ISSN: 1756-3305