Tortoise tick Hyalomma aegyptium as long term carrier of Q fever agent Coxiella burnetii—evidence from experimental infection

Abstract

The experimental study investigated the ability of tortoise tick Hyalomma aegyptium to play a role in forming and maintaining natural foci of Q fever. We tested the competence of H. aegyptium larvae to acquire Coxiella burnetii infection from mammals, serve as a C. burnetii vector between mammalian hosts, and be a long-term carrier of C. burnetii, including interstadial transmission. H. aegyptium larvae were allowed to feed on guinea pigs experimentally infected with C. burnetii. Engorged larvae molted to nymphs, some of which were preserved in 96% ethanol and later examined by polymerase chain reaction (PCR) using C. burnetii-specific primers (CBCOS, CBCOE). Prevalence of C. burnetii among these nymphs was 5.6% (n=235). Remaining nymphs then fed on other, C. burnetii-negative guinea pigs; and according to results of both, micro-agglutination reaction, and ELISA, they successfully transmitted C. burnetii to those new hosts. Detached engorged nymphs molted to adults, which were kept alive long term and then placed in 96% ethanol 383 days post-infection. Thereafter, they were examined by PCR in the same manner as were the nymphs. Prevalence of C. burnetii among adult H. aegyptium was 28.9% (n=90). According to our results, tortoise-specific ticks have indisputable potential in the epidemiology of Q fever natural foci.

Zoonotic pathogens associated with Hyalomma aegyptium in endangered tortoises: evidence for host-switching behaviour in ticks?

“…Experimental trials are usually long and difficult to perform, hence the need for a preliminary assessment of the carrier status in natural populations. Until now, experimental proof of the vectorial capacity of H. aegyptium was shown for several pathogens: Hemolivia mauritanica [15], Hepatozoon kisrae [16], Rickettsia aeschlimannii [17] and Coxiella burnetii [18]. …”

Life cycle of tortoise tick Hyalomma aegyptium under laboratory conditions

“…Particularly long-living tortoises could have potential in long-term maintenance of natural foci of infectious diseases and their ticks can serve as vectors (Burridge and Simmons 2003;Peter et al 2000). Ticks of tortoises (including H. aegyptium) as blood sucking arthropods have indisputable potential to play a role in transmission of pathogenic agents (Blanc 1961;Š iroký et al 2010). Therefore, knowledge of biology of such host-specific ticks should not be overlooked.…”

Gefahren der Übertragung von Krankheitserregern durch Schildzecken in Deutschland

“…[25]. Hierzu gehört auch der internationale Referenzstamm "Nine Mile", der ebenfalls aus einer Zecke isoliert wurde [26].…”

“…Hierzu gehört auch der internationale Referenzstamm "Nine Mile", der ebenfalls aus einer Zecke isoliert wurde [26]. Die höchste Erregerkonzentration findet sich im ZeckenKot [25], wodurch besonders bei der Schafschur eine Gefährdung von Personen ausgeht. Bei den einheimischen Zecken scheinen nur die beiden Dermacentorarten eine Rolle zu spielen [27].…”