CiteULike: neteler Materna

Tick-borne encephalitis virus expansion to higher altitudes correlated with climate warming.

Vlasta Danielová — 2008-04-28T15:35:33-00:00

International journal of medical microbiology : IJMM (21 April 2008)

Since 2002, the expansion of Ixodes ricinus ticks and tick-borne infection agents have been studied in the Krkonose Mts., Czech Republic. Tick-borne encephalitis virus was detected by means of RT-PCR. In 2003, it was detected in 2 out of 491 ticks at 620 and 710-720m a.s.l., respectively, and in 3 out of 939 ticks at 600m a.s.l. at the same locality in 2004. In 2005, tick-borne encephalitis virus was detected in 5 out of 295 ticks at 900-1100m a.s.l., which is above the formerly known altitudinal limit of I. ricinus distribution. The reason for that could be found in the changing climate. Based on the meteorological data collected in the Krkonose Mts., 1961-2005, there was a significant increase in the mean annual temperature (1.3-1.4 degrees C) over that period, namely by 2-3.5 degrees C in May through August. Thus, with respect to the average vertical temperature gradient in summer of about 0.6 degrees C/100m, 2 degrees C correspond to 300-350m in altitude, and accordingly 3.5 degrees C correspond to a shift in altitude of approximately 550-600m, that being in accordance with environmental conditions of the former I. ricinus altitudinal limit confirmed in the Krkonose Mts. 20 years ago.

Extension of Ixodes ricinus ticks and agents of tick-borne diseases to mountain areas in the Czech Republic

Vlasta Danielova — 2006-07-23T11:52:25-00:00

International Journal of Medical Microbiology, Vol. 296, No. Supplement 1. (22 May 2006), pp. 48-53.

Along with the shift of the hard tick Ixodes ricinus to higher altitudes observed in the Czech Republic a corresponding shift of tick-borne infections to higher altitudes has been expected. Therefore, I. ricinus ticks, mainly nymphs, were investigated for the presence of tick-borne viruses, tick-borne encephalitis (TBE), Tribec and Eyach, and the spirochaete Borrelia burgdorferi sensu lato in the Sumava and Krkonose Mountains (Czech Republic). The TBE virus and different genospecies of B. burgdorferi s.l. were detected by RT-PCR and PCR, respectively. TBE virus was detected in ticks at 620 and 720 m above sea level (a.s.l.), B. burgdorferi s.l. was detected in ticks up to 1065 m a.s.l. Four genospecies of B. burgdorferi s.l. were identified, B. afzelii, B. garinii, B. burgdorferi sensu stricto, and B. valaisiana. Some nymphs carried multiple Borrelia infections. The conditions of tick-borne agents' distribution and potential epidemiological consequences are discussed.

Altitudinal distribution limit of the tick Ixodes ricinus shifted considerably towards higher altitudes in central Europe: results of three years monitoring in the Krkonose Mts. (Czech Republic).

J Materna — 2005-10-25T07:07:21-00:00

Cent Eur J Public Health, Vol. 13, No. 1. (March 2005), pp. 24-28.

The aim of the study was to monitor present status of the Ixodes ricinus tick vertical distribution in the Krkonose Mts. (Czech Republic) and evaluate its potential changes. Two methods were used: monitoring of tick presence on dogs in 2001-2002 and direct monitoring of host-seeking ticks by flagging on two vertical transects reaching from 620 to 1270 m above sea level (a. s. l.) and from 600 to 1020 m in 2002-2003. Moreover ticks were monitored by flagging at another 13 localities situated in 800-1299 m a. s. l. in 2003. Both monitoring methods revealed an obvious shift in altitudinal distribution limit of the tick I. ricinus in the Krkonose Mts. They both showed that ticks recently penetrate even up to a timberline (approximately 1250 m a. s. l.). The number of recorded host-seeking ticks rapidly decreased with increasing altitude. Whereas the average number of recorded nymphs converted per 60 minutes of flagging reached 15.2-25.7 nymphs in 700-799 m a. s. l. and 3.3-23.3 in 800-899 m, it was 4-9.6 nymphs in 900-999 m, 1.5-1.7 nymphs in 1000-1099 m and only 0.2 nymph in 1100-1299 m a. s. l. The observed shift of the tick altitudinal distribution limit at the same time results in extension of areas with potential risk of tick-borne diseases.