Most cited article - PubMed ID 17237970
Hyalomma aegyptium as dominant tick in tortoises of the genus Testudo in Balkan countries, with notes on its host preferences
Crimean-Congo haemorrhagic fever virus (CCHFV) poses a significant public health threat due to its potential for causing severe disease in humans and its wide geographic distribution. The virus, primarily transmitted by Hyalomma ticks, is prevalent across Africa, Asia, Europe, and the Middle East. Understanding the virus's spread among tick populations is crucial for assessing its transmission dynamics. Vertebrates play a key role in CCHF epidemiology by supporting tick populations and acting as virus carriers during viremia. Livestock, such as cattle, sheep, and goats, amplify the virus and increase tick numbers, posing zoonotic risks. Wildlife, while asymptomatic, can serve as reservoirs. Birds generally do not show signs of the virus but can introduce infected ticks to new regions. This review compiles information on CCHFV's tick vectors and vertebrate hosts, emphasizing their roles in the virus's transmission dynamics. Understanding these dynamics is essential for developing effective control and prevention strategies.
- Keywords
- Crimean-Congo haemorrhagic fever virus, livestock, ticks, wildlife, zoonotic disease,
- Publication type
- Journal Article MeSH
- Review MeSH
Wild birds are common hosts of ticks and can transport them for long distances, contributing to the spreading of tick-borne pathogens. The information about ticks on birds and tick-borne pathogens in Greece is limited. The present study aimed to evaluate the prevalence and species of ticks infesting wild resident birds (mostly small passerines) in Greece, and to assess Borrelia and Rickettsia infection in the collected ticks. Detection of Borrelia burgdorferi s.l. was performed by nested PCR targeting the flaB gene. Rickettsia spp. were detected by PCR targeting the gltA and ompA genes. Seven (2 %) out of 403 birds examined in northern Greece in 2013 were infested with 15 ticks, identified as Ixodes frontalis, Ixodes acuminatus, Hyalomma marginatum, Hyalomma aegyptium and Hyalomma sp. All ticks were negative for Borrelia spp. while four of them were positive for rickettsiae (Rickettsia aeschlimannii in H. aegyptium and Rickettsia sp. in I. frontalis, H. aegyptium and H. marginatum). Ixodes acuminatus is reported for the first time in Greece and Sylvia borin is reported as a new host record for I. acuminatus.
- Keywords
- Birds, Borrelia, Greece, Rickettsia, Tick-borne pathogens, Ticks,
- MeSH
- Borrelia isolation & purification MeSH
- Animals, Wild * MeSH
- Tick Infestations epidemiology parasitology veterinary MeSH
- Ixodidae microbiology MeSH
- Bird Diseases epidemiology microbiology parasitology MeSH
- Passeriformes MeSH
- Birds MeSH
- Rickettsia isolation & purification MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Greece epidemiology MeSH
It is the first time that Crimean-Congo haemorrhagic fever virus (CCHFV), causing potentially lethal disease of humans, has been reported from the Middle East region and from the tortoise tick Hyalomma aegyptium from a tortoise host, whose epidemiological significance may have remained almost completely overlooked so far. We used RT-PCR to screen for 245 ticks collected from 38 Testudo graeca tortoise individuals. Results of our genetic screening provide unambiguous evidence of occurrence of CCHFV in this region and host, suggesting a potentially important role of H. aegyptium in CCHF epidemiology.
- MeSH
- Phylogeny MeSH
- Haplotypes MeSH
- Tick Infestations epidemiology microbiology veterinary MeSH
- Ticks virology MeSH
- Hemorrhagic Fever Virus, Crimean-Congo genetics isolation & purification MeSH
- Turtles parasitology MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Letter MeSH
- Research Support, Non-U.S. Gov't MeSH
- Geographicals
- Syria epidemiology MeSH
- Turkey epidemiology MeSH
The tortoise tick Hyalomma aegyptium has a typical three-host life-cycle. Whereas its larvae and nymphs are less host-specific feeding on a variety of tetrapods, tortoises of the genus Testudo are principal hosts of adults. Ticks retained this trait also in our study under laboratory conditions, while adults were reluctant to feed on mammalian hosts. Combination of feeding larvae and nymphs on guinea pigs and feeding of adults on Testudo marginata tortoises provided the best results. Feeding period of females was on average 25 days (range 17-44), whereas males remain after female engorgement on tortoise host. Female pre-oviposition period was 14 days (3-31), followed by 24 days of oviposition (18-29). Pre-eclosion and eclosion, both together, takes 31 days (21-43). Larvae fed 5 days (3-9), then molted to nymphs after 17 days (12-23). Feeding period of nymphs lasted 7 days (5-10), engorged nymphs molted to adults after 24 days (19-26). Sex ratio of laboratory hatched H. aegyptium was nearly equal (1:1.09). The average weight of engorged female was 0.95 (0.72-1.12) g. The average number of laid eggs was 6,900 (6,524-7,532) per female, it was significantly correlated with weight of engorged female. Only 2.8% of engorged larvae and 1.8% of engorged nymphs remained un-molted and died. Despite the use of natural host species, feeding success of females reached only 45%. The whole life-cycle was completed within 147 days (98-215).
- MeSH
- Longevity MeSH
- Ixodidae growth & development physiology MeSH
- Oviposition MeSH
- Larva growth & development physiology MeSH
- Nymph growth & development physiology MeSH
- Sex Ratio MeSH
- Molting MeSH
- Feeding Behavior MeSH
- Turtles parasitology MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
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.
