New reptilian host for the reptile tick Amblyomma limbatum Neumann (Acari: Ixodidae), from Alice Springs, Northern Territory

Parasites impact on the survival of individual animals and populations, by decreasing health and nutrition and in the longer-term potentially reducing reproductive outcomes (Vilcins et al., 2005). Ticks have been documented to reduce immunological fitness through parasitemia leading to anemia and blood cell abnormalities (Telford, 1984), reduced growth, survivorship and reproductive output (Madsen et al., 2005). They have also been shown to impact behavior through their role as vectors (Bouma et al., 2007)

The impact of ticks and tick-borne diseases on native animal species in Australia

Ectoparasites are a leading cause of arthropod-borne disease in animals, and humans. Defined as arthropods which spend an entire portion of their life cycle on the host, ectoparasites include the ticks and mites (Acarina), and the lice and fleas of the insect family. Their role in human disease transmission has been well documented, as has their importance in agricultural and domestic animals. Little however has been done to comprehensively examine the role these organisms may play in disease transmission and their impact upon native Australian fauna. It is important to consider the effects of such disease agents on the survival of both captive and wild native animal populations, particularly as exposure to a novel pathogen may remove endangered animals that are a vital pool of genetic diversity

Molecular and morphological description of a Hepatozoon species in reptiles and their ticks in the Northern Territory, Australia

Ticks, representing 3 species of Amblyomma, were collected from the water python (Liasis fuscus) and 3 additional reptile species in the Northern Territory, Australia, and tested for the presence of Hepatozoon sp., the most common blood parasites of snakes. In addition, blood smears were collected from 5 reptiles, including the water python, and examined for the presence of the parasite. Hepatozoon sp. DNA was detected in all tick and reptile species, with 57.7% of tick samples (n = 187) and 35.6% of blood smears (n=35) showing evidence of infection. Phylogenetic analysis of the 18S rRNA gene demonstrated that half of the sequences obtained from positive tick samples matched closest with a Hepatozoon species previously identified in the water python population. The remaining sequences were found to be more closely related to mammalian and amphibian Hepatozoon species. This study confirms that species of Amblyomma harbor DNA of the same Hepatozoon species detected in the water pythons. The detection of an additional genotype suggests the ticks may be exposed to 2 Hepatozoon species, providing further opportunity to study multiple host-vector-parasite relationships.9 page(s

Bartonella-Like DNA Detected in Ixodes tasmani Ticks (Acari: Ixodida) Infesting Koalas (Phascolarctos cinereus) in Victoria, Australia

A total of 42 ticks comprising Ixodes tasmani (n = 41) and Ixodes trichosuri (n = 1) were collected from wild koalas (Phascolarctos cinereus) at the Koala Convention Centre, Philip Island, Victoria, Australia and screened for the presence of Bartonella using the target gene gltA. Bartonella-like DNA was detected in 4 of the 19 pooled tick samples (21%). All positive ticks were male. Analysis of partial sequences for the gltA gene indicated the presence of a Bartonella-related species similar to that reported in another Ixodid species. This is the first report of Bartonella-like organisms in a native Australian marsupial.5 page(s

Detection of a Hepatozoon and spotted fever group Rickettsia species in the common marsupial tick (Ixodes tasmani) collected from wild Tasmanian devils (Sarcophilus harrisii), Tasmania

Tasmanian devils are the largest extant marsupial carnivores, confined to the Australian island state of Tasmania. The iconic marsupial has dramatically declined in number since the discovery of devil facial tumor disease in 1996 and efforts are being made to uncover vital information to assist in the long-term survival of the species. Ticks are the main vectors of arthropod-borne disease in animals, raising the question of whether Tasmanian devils may be host to arthropods capable of harboring infectious agents. Partially engorged ticks were collected from 35 wild Tasmanian devils and tested for the presence of a range of tick-borne genera. A spotted fever group Rickettsia was detected in 45.5% of samples of the tick Ixodes tasmani (n = 44), from all trapping locations, sharing close sequence identity to members of the Rickettsia massiliae group. A Hepatozoon species was also identified in 34.1% of the same sample set, sharing sequence similarities to Hepatozoon felis, a known pathogen of felids. Dual detection was identified in 13.6% of tick samples, where prevalence of the two genera overlapped. The existence of two previously undetected species of genera known for containing pathogens identifies additional potential risks to the health of the devil population

Molecular detection of Rickettsia, Coxiella and Rickettsiella DNA in three native Australian tick species

Three Australian native animal species yielded 60 samples composed of three indigenous ticks. Hosts included twelve koalas, two echidnas and one wombat from Victoria, and ticks were of the species Ixodes tasmani (n = 42), Bothriocroton concolor (n = 8) and B. auruginans (n = 10), respectively. PCR screening and sequencing detected a species of Coxiella, sharing closest sequence identity to C. burnetii (>98%), in all B. auruginans, as well as a species of Rickettsia, matching closest to R. massiliae, in 70% of the same samples. A genotype sharing closest similarity to Rickettsia bellii (>99%) was identified in three female B. concolor collected from one of the echidnas. Three samples of I. tasmani, taken from three koalas, yielded different genotypes of Rickettsiella. These results represent the first detection of the three genera in each tick species and identify a high level of previously undetected bacterial diversity in Australian ticks

Molecular and morphological description of a Hepatozoon species in reptiles and their tricks in the Northern Territory, Australia

Ticks, representing 3 species of Amblyomma, were collected from the water python (Liasis fuscus) and 3 additional reptile species in the Northern Territory, Australia, and tested for the presence of Hepatozoon sp., the most common blood parasites of snakes. In addition, blood smears were collected from 5 reptiles, including the water python, and examined for the presence of the parasite. Hepatozoon sp. DNA was detected in all tick and reptile species, with 57.7% of tick samples (n = 187) and 35.6% of blood smears (n = 35) showing evidence of infection. Phylogenetic analysis of the 18S rRNA gene demonstrated that half of the sequences obtained from positive tick samples matched closest with a Hepatozoon species previously identified in the water python population. The remaining sequences were found to be more closely related to mammalian and amphibian Hepatozoon species. This study confirms that species of Amblyomma harbor DNA of the same Hepatozoon species detected in the water pythons. The detection of an additional genotype suggests the ticks may be exposed to 2 Hepatozoon species, providing further opportunity to study multiple host–vector–parasite relationships

Evidence for the presence of Francisella and spotted fever group Rickettsia DNA in the tick Amblyomma fimbriatum (Acari: Ixodidae), Northern Territory, Australia

Ticks (n _ 252) were collected from five wild-caught reptile species during routine trapping in the Djukbinj National Park and Fogg Dam Reserve, Northern Territory, Australia. Pooling of ticks (one to four ticks per pool), according to sex or host animal, resulted in 187 samples used for screening for the presence of Rickettsia species via molecular methods. Rickettsia DNA was detected via the amplification of the gltA, ompA, and ompB genes in 57 (34%) of the 187 tick samples, all of which contained only the tick Amblyomma fimbriatum Koch (Acari: Ixodidae). Further amplification and sequencing of nine of the positive samples (4.8%) for the gltA, ompA, ompB, 17-kDa, and 16S rRNA genes identified a Rickettsia species sharing closest identity to Rickettsia tamurae. In addition, amplification and sequencing of the 16S rRNA gene detected in the same tick samples the presence of a Francisella species closely related to other tick-borne Francisellae identified in ticks from the Northern Hemisphere

Absence of the symbiont Candidatus Midichloria mitochondrii in the mitochondria of the tick Ixodes holocyclus

Candidatus Midichloria mitochondrii (M. mitochondrii) belongs to a novel clade of bacteria within the order Rickettsiales. Recent PCR-based screening studies indicate that it is present in a number of blood-sucking arthropods, as well as the blood of some vertebrates. Its medical and veterinary significance remains to be determined. Electron microscopic examinations of M. mitochondrii have thus far been conducted on two infected tick species. Remarkably, the bacterium was found in abundance within the mitochondria of the ovarian cells of each tick species. This makes it the only characterized bacterium able to invade the mitochondria of any multicellular organism. To examine whether mitochondrial invasion is a consistent characteristic of M. mitochondrii, we examined two tick species found in Eastern Australia. One of these species, Ixodes holocyclus, was infected with two M. mitochondrii strains; however, no bacteria were seen in the mitochondria. Comparative studies involving these strains may shed light on the unique phenomenon of mitochondrial invasion