Spread of ticks and tick-borne diseases in Germany due to global warming

Abstract

Tick-transmitted diseases like tick-borne encephalitis and Lyme Borreliosis have been well known in Germany for decades. Global climate changes may influence the emergence and reemergence of diseases. Ongoing research now gives an additional focus on other tick-borne pathogens such as Coxiella burnetii, Rickettsia conorii, Anaplasma phagocytophilum and Babesia spp., the causative agents of Q-fever, Mediterranean spotted fever, Anaplasmosis and Babesiosis, respectively. The epidemiology of these pathogens was investigated on ticks as well as on rodents, the main hosts. Therefore adults of Dermacentor spp. (n = 862) and rodents (n = 119) were collected and examined for the existence of C. burnetii and Rickettsia spp. by polymerase chain reaction (PCR). In none of the ticks and rodents C. burnetii could be detected, in contrast to Rickettsia spp. where the infection rate in ticks was about 20%. Over and above that, nymphs and adults of Ixodes ricinus were also collected and investigated by PCR for A. phagocytophilum (n = 5,424), Rickettsia helvetica (n = 1,187) and Babesia spp. (n = 3,113). Thereby infection rates of 1%, 8.9% and 1%, respectively, could be determined. The prevalence in rodents was 5.3% for A. phagocytophilum and 0.8% for Babesia microti. None of the rodents was R. helvetica positive.

Distinct Host Species Correlate with Anaplasma phagocytophilum ankA Gene Clusters

“…However, the presence of A. phagocytophilum in I. ricinus ticks (5, 21) and rodents (26) as potential reservoir hosts has been demonstrated. As part of the present study, we showed for the first time that in Germany sheep, roe deer, and red deer were also infected with A. phagocytophilum.…”

Update on tick-borne bacterial diseases in Europe

“…C. burnetii has been detected in 140 species of ticks in 12 genera throughout the word (absent in New Zealand), but the role of ticks in Q fever transmission to humans is very small (Parola & Raoult, 2001b;Tissot-Dupont & Raoult, 2008). Recently, none of 862 Dermacentor ticks tested positive for C. burnetii in Germany, and one specimen of Haemaphysalis punctata from 691 questing adult ixodid ticks was positive in Spain (Hartelt et al, 2008;Barandika et al, 2008). Q fever is usually acquired by the ingestion or inhalation of virulent organisms from infected mammals and their products, most frequently goats, sheep, and cats.…”

Diversity of Babesia and Rickettsia Species in Questing Ixodes ricinus: A Longitudinal Study in Urban, Pasture, and Natural Habitats

“…B. microti has been detected in Europe, for example, in the bank vole (Myodes glareolus) (Duh et al 2003, Beck et al 2011, Tadin et al 2012, the common shrew (Sorex araneus) (Bown et al 2011), and the field vole (Microtus agrestis) (Bown et al 2011), which are suggested as reservoir hosts, but also in the yellow-necked mouse (Apodemus flavicollis) (Duh et al 2003, Sinski et al 2006, Beck et al 2011, Tadin et al 2012). In Germany, B. microti has been detected previously in a striped field mouse (Apodemus agrarius) (Silaghi et al 2012) and with a prevalence of 1.6% in rodents of the family Arviculidae (Hartelt et al 2008). Bank voles are most abundant in woodlands, whereas field vole and the common shrew achieve highest density in long grass and scrub (Dickman and Doncaster 1987).…”