Amblyomma Species Research Articles

A Third Amblyomma Species and the First Tick-Borne Rickettsia in Chile

During November 2010, three ticks were collected from three dogs living in the rural area of Arica, northern Chile. Morphological analyses of the ticks in the laboratory revealed that they were most similar to Amblyomma maculatum Koch and Amblyomma triste Koch. However, because of unique metatarsal spurs, neither of the Chilean specimens could be assigned with certainty to A. maculatum or A. triste, based on external morphology. The mitochondrial 16S rRNA gene partial sequences obtained from two Chilean specimens were 99.5% identical to A. triste from Uruguay, and 99.0% identical to A. maculatum from the United States. Through phylogenetic analysis inferred from partial 16S rRNA sequences, the Chilean specimens were classified as A. triste. Molecular analyses also showed that one of the three Chilean ticks was infected by Candidatus 'Rickettsia andeanae'. These findings extend the geographical distribution of A. triste to Chile, where no tick-associated rickettsia had been reported previously.

Ticks on free-living wild mammals in Emas National Park, Goias State, central Brazil

This paper reports the occurrence of ticks on different species of free-ranging wild mammals in Emas National Park, Goias State, Brazil. Between November 1999 and July 2008, ticks were collected from free-ranging wild mammals during 330 capture events. The tick species Amblyomma cajennense (Fabricius, 1787), Amblyomma coelebs Neumann, 1899, Amblyomma naponense (Packard, 1869), Amblyomma ovale Koch, 1844, Amblyomma parvum Aragao, 1908, Amblyomma tigrinum Koch, 1844, Amblyomma triste Koch, 1844, and Rhipicephalus microplus (Canestrini, 1888) were identified on hosts of the order Carnivora. Among other host orders (Xenarthra, Artiodactyla, Perissodactyla, Rodentia, Didelphimorphia, Primates), specimens of A. cajennense, A. coelebs, A. ovale, A. triste, Amblyomma pseudoconcolor Aragao, 1908, A. naponense and Amblyomma nodosum Neumann, 1899 were identified. Although most of the tick-host associations found in this study have been previously reported, this is the first report of adults of A. tigrinum parasitizing a pampas cat, Leopardus colocolo (Molina, 1782), nymphs of Amblyomma parvum and Amblyomma ovale on Cerdocyon thous (Linnaeus, 1766), nymphs of Amblyomma naponense on C. thous and Tayassu tajacu (Linnaeus, 1758), nymphs of Amblyomma triste on C. thous and L. colocolo, nymphs of Amblyomma coelebs on Puma yagouaroundi (Geoffroy, 1803) and Dasyprocta azarae Lichtenstein, 1823, and nymphs of Amblyomma cajennense on L. colocolo, Conepatus semistriatus (Boddaert, 1785), Galictis cuja (Molina, 1782) and Nasua nasua (Linnaeus, 1766). This study is therefore a significant contribution to our knowledge of the ectoparasites associated with free-ranging Brazilian wild mammals.

New tick-host records (Acari: Ixodidae) from Mississippi, U.S.A

Thirty-five specimens of at least five tick species—Amblyomma americanum, Dermacentor variabilis, Haemaphysalis leporispalustris, Ixodes cookei and Ixodes scapularis—were collected from eight mammal species in Rankin County, Mississippi, U.S.A. All are new county records. Three collections of D. variabilis from the eastern mole, Scalopus aquaticus, constitute the first report of tick collections anywhere in Mississippi from a mole.

The Amblyomma (Acari: Ixodida: Ixodidae) of Mexico: Identification Keys, Distribution and Hosts CARMEN GUZMÁN-CORNEJO (Mexico), RICHARD G. ROBBINS (USA), ALBERTO A. GUGLIELMONE (Argentina), GRISELDA MONTIEL-PARRA (Mexico) & TILA MARÍA PÉREZ (Mexico)

Taxonomic keys, distributional data and hosts are provided for the 26 Amblyomma species known from Mexico. Members of this genus have been collected in 30 of Mexico’s 32 states and are associated with 43 nominal vertebrate taxa, of which 40 have been identified to species and four (Python sp., Myrmecophaga tridactyla, Tamandua tetradactyla, Tupinambis teguixin) are non-native. Mammals are the principal class of vertebrates parasitized by Mexican Amblyomma species, followed by reptiles, birds and amphibians. Our knowledge of Mexican Amblyomma is still far from complete because many potential hosts have not yet been examined and vast areas of the country remain unexplored.

Coxiella Symbionts in the Cayenne Tick Amblyomma cajennense

Members of the Coxiella genus are intracellular bacteria that can infect a variety of animals including humans. A symbiotic Coxiella was recently described in Amblyomma americanum ticks in the Northern Hemisphere with no further investigations of other Amblyomma species in other geographic regions. These ixodid ticks represent a group of important vectors for human infectious agents. In the present work, we have demonstrated that symbiotic Coxiella (SCox) are widespread, occurring in South America and infecting 100% of all life stages and eggs of the Cayenne ticks Amblyomma cajennense from Brazil and the USA. Using light microscopy, in situ hybridization, and PCR, we demonstrated SCox in salivary glands, ovaries, and the intestines of A. cajennense. These symbionts are vertically and transtadially transmitted in laboratory reared A. cajennense, and quantitative PCR analyses indicate that SCox are more abundant in adult female ticks, reaching values corresponding to an 11×, 38×, and 200× increase in SCox 16S rRNA gene copy number in unfed females, compared to unfed nymphs, larvae, and eggs, respectively. Phylogenetic analyses showed distinct SCox subpopulations in the USA and Brazil and demonstrated that SCox bacteria do not group with pathogenic Coxiella burnetii.

Tick-Borne Bacteria in Free-Living Jaguars (Panthera onca) in Pantanal, Brazil

Tick-borne bacteria were investigated in 10 free-living jaguars and their ticks in the Pantanal biome, Brazil. Jaguar sera were tested by indirect fluorescent antibody assays using Rickettsia rickettsii, Rickettsia parkeri, Rickettsia amblyommii, Rickettsia rhipicephali, Rickettsia felis, Rickettsia bellii, Ehrlichia canis, and Coxiella burnetii as crude antigens. All 10 jaguar sera reacted (titer ≥ 64) to at least one Rickettsia species; 4 and 3 sera reacted with E. canis and C. burnetii, respectively. One jaguar presented antibody titer to R. parkeri at least fourfold higher than those to any of the other five Rickettsia antigens, suggesting that this animal was infected by R. parkeri. Ticks collected from jaguars included the species Amblyomma cajennense, Amblyomma triste, and Rhipicephalus (Boophilus) microplus. No Rickettsia DNA was detected in jaguar blood samples, but an A. triste specimen collected on a jaguar was shown by PCR to be infected by R. parkeri. The blood of two jaguars and samples of A. triste, A. cajennense, and Amblyomma sp. yielded Ehrlichia DNA by PCR targeting the ehrlichial genes 16S rRNA and dsb. Partial DNA sequences obtained from PCR products resulted in a new ehrlichial strain, here designated as Ehrlichia sp. strain Jaguar. A partial DNA sequence of the 16S rRNA gene of this novel strain showed to be closest (99.0%) to uncultured strains of Ehrlichia sp. from Japan and Russia and 98.7% identical to different strains of Ehrlichia ruminantium. The ehrlichial dsb partial sequence of strain jaguar showed to be at most 80.7% identical to any Ehrlichia species or genotype available in GenBank. Through phylogenetic analysis, Ehrlichia sp. strain jaguar grouped in a cluster, albeit distantly, with different genotypes of E. ruminantium. Results highlight risks for human and animal health, considering that cattle ranching and ecotourism are major economic activities in the Pantanal region of Brazil.

Tick Surveillance in Great Britain

The ability for public/veterinary health agencies to assess the risks posed by tick-borne pathogens is reliant on an understanding of the main tick vector species. Crucially, the status, distribution, and changing trends in tick distribution and abundance are implicit requirements of any risk assessment; however, this is contingent on the quality of tick distribution data. Since 2005 the Health Protection Agency has promoted an enhanced tick surveillance program. Through engagement with a variety of public and veterinary health agencies and practitioners (e.g., clinicians and veterinarians), wildlife groups (deer society, zoos, animal refuge centers, and academics), and amateur entomologists, >4000 ticks from 900 separate records across Great Britain have been submitted, representing 14 tick species (Ixodes ricinus, Ixodes hexagonus, Ixodes acuminatus, Ixodes arboricola, Ixodes canisuga, Ixodes frontalis, Ixodes lividus, Ixodes trianguliceps, Ixodes ventalloi, Carios vespertilionis, Dermacentor reticulatus, Haemaphysalis punctata, Hyalomma marginatum, and Amblyomma species). The majority of ticks submitted were I. ricinus (81%), followed by I. hexagonus (10%) and I. frontalis (2.5%). Predominant host groups include companion animals (411 records), humans (198 records), wild birds (111 records), and large wild mammals (88 records), with records also from small/medium wild mammals, livestock, the environment and domestic/aviary birds. The scheme has elucidated the detection of two nonnative tick species, the expansion of previously geographically restricted D. reticulatus and produced ground data on the spread of I. ricinus in southwest England. It has also provided a forum for submission of ticks from the concerned public and particularly those infected with Lyme borreliosis, thus raising awareness among public health agencies of the increased peri-urban tick problem in Britain. Our results demonstrate that it is possible to run a cost-effective nationwide surveillance program to successfully monitor endemic tick species, identify subtle changes in their distribution, and detect the arrival and presence of exotic species.

Comparison of two methods for collecting free-living ticks in the Amazonian forest

In the present study, we compared 2 methods for collecting ixodid ticks on the verges of animal trails in a primary Amazon forest area in northern Brazil. (i) Dragging: This method was based on passing a 1-m 2 white flannel over the vegetation and checking the flannel for the presence of caught ticks every 5–10 m. (ii) Visual search: This method consisted of looking for questing ticks on the tips of leaves of the vegetation bordering animal trails in the forest. A total of 103 adult ticks belonging to 4 Amblyomma species were collected by the visual search method on 5 collecting dates, while only 44 adult ticks belonging to 3 Amblyomma species were collected by dragging on 5 other collecting dates. These values were statistically different (Mann–Whitney Test, P = 0.0472). On the other hand, dragging was more efficient for subadult ticks, since no larva or nymph was collected by visual search, whereas 18 nymphs and 7 larvae were collected by dragging. The visual search method proved to be suitable for collecting adult ticks in the Amazon forest; however, field studies should include a second method, such as dragging in order to maximize the collection of subadult ticks. Indeed, these 2 methods can be performed by a single investigator at the same time, while he/she walks on an animal trail in the forest.

Ticks of the genus Amblyomma (Acari: Ixodidae) infesting tapirs (Tapirus terrestris) and peccaries (Tayassu pecari) in Peru

Abstract During 2008–2009, ticks were opportunistically collected from free-living lowland tapirs (Tapirus terrestris) and white-lipped peccaries (Tayassu pecari) during two studies of the ecology of Amazonian ungulates near or within two conservation areas in Madre de Dios, Peru. From tapirs, adults of the following tick species were collected: Amblyomma coelebs, Amblyomma incisum, Amblyomma latepunctatum, Amblyomma oblongoguttatum, Amblyomma ovale, and Amblyomma scalpturatum. Ticks collected from peccaries included adults of Amblyomma naponense and A. oblongoguttatum, nymphs of A. coelebs and A. latepunctatum, and larvae of Amblyomma sp. The 7 Amblyomma species collected in the present study have been previously reported in Peru. Although it is a common parasite of tapirs and/or peccaries in the Neotropical Region, we provide the first report of A. oblongoguttatum on tapirs in Peru. In addition, we provide the first report of A. coelebs and A. latepunctatum nymphs on peccaries. For nymphs of the latter ...

Nymphs of the genus Amblyomma (Acari: Ixodidae) of Brazil: descriptions, redescriptions, and identification key

Together with the larval stage, the nymphal stage of ticks of the genus Amblyomma are the most aggressive ticks for humans entering areas inhabited by wildlife and some domestic animals in Brazil. However, due to the absence of morphological descriptions of the nymphal stage of most Brazilian Amblyomma species, plus the lack of an identification key, little or nothing is known about the life history of Amblyomma spp. nymphs in the country. In the present study, morphological description of the nymphal stage, illustrating important external characters through scanning electron microscopy, is provided for nymphs of 15 Amblyomma species that occur in Brazil, for which the nymphal stage had never been described: A. aureolatum, A. auricularium, A. calcaratum, A. coelebs, A. fuscum, A. humerale, A. incisum, A. latepunctatum, A. naponense, A. nodosum, A. ovale, A. pacae, A. pseudoconcolor, A. scalpturatum, A. varium. In addition, the nymphal stage of 12 Amblyomma species, which had been previously described, are redescribed: A. brasiliense, A. cajennense, A. dissimile, A. dubitatum, A. longirostre, A. oblongoguttatum, A. parkeri, A. parvum, A. romitii, A. rotundatum, A. tigrinum, A. triste. The descriptions and redescriptions totalized 27 species. Only 2 species ( A. geayi, A. goeldii) out of the 29 Amblyomma species established in Brazil are not included in the present study. A dichotomous identification key is included to support taxonomic identification of the nymphal stage of 27 Amblyomma species established in Brazil.

Ticks (Acari: Ixodidae) Parasitizing Canines and Deer in Arkansas

Increased occurrence of tick-borne diseases requires the surveillance of tick species associated with humans and the animals they contact. Tick species were collected from canines and deer throughout Arkansas by veterinarians during December 2006 to October 2007, while personnel with the Arkansas Game and Fish Commission collected ticks from hunter-killed deer throughout the 2007 hunting season (Oct-Dec). Five tick species were collected: Ixodes scapularis Say (51%), Amblyomma americanum (L.) (22%), Rhipicephalus sanguineus (Latreille) (12%), A. maculatum (Koch) (7%), Dermacentor variabilis (Say) (6%), and unidentified Amblyomma species (2%). Tick collections from canines were A. americanum (45%), whereas 89% of ticks collected from deer were I. scapularis. These 2 tick species also were found simultaneously infesting the same canine and deer hosts. Our data identify 5 tick species and update the current distribution of each species that may be involved in the Arkansas tick-borne disease cycle.

Population Genetics ofAmblyomma americanum(Acari: Ixodidae) Collected From Arkansas

Lone star ticks, Amblyomma americanum L. (Acari: Ixodidae), infest multiple hosts such as birds, and mammals of various sizes (rodents to white-tailed deer) and can harbor human pathogens such as Borrelia lonestari and Ehrlichiosis chaffeensis. The population structure of 251 A. americanum ticks, collected from canines and two white-tailed deer in six Arkansas ecoregions, was examined using DNA sequences of a 247-bp region of the mitochondrial DNA ribosomal RNA 16S gene. Of the 247 nucleotide characters, 26 were variable. Thirty-three haplotypes were identified of which 25 haplotypes occurred once (10%). The most common haplotype was Aa25, occurring in 60% of the samples and found in all six ecoregions. The excess of low frequency haplotypes combined with the overall negative Tajima’s D and Fu and Li statistics suggests population expansion. Phylogenetic relationships of the 33 A. americanum haplotypes were constructed with other Amblyomma species and identified A. americanum as a monophyletic species with two groups. The patterns of high nucleotide and haplotype diversity found in this study suggests that the A. americanum population is expanding perhaps due to its ability to survive in a variety of habitats and feed on multiple hosts. Given the gene flow in Arkansas, the spread of acaricide resistance and pathogens may be rapid.

Population Genetics of <I>Amblyomma americanum</I> (Acari: Ixodidae) Collected From Arkansas

Lone star ticks, Amblyomma americanum L. (Acari: Ixodidae),infest multiple hosts such as birds, and mammals of various sizes (rodents to white-tailed deer) and can harbor human pathogens such as Borrelia lonestari and Ehrlichiosis chaffeensis. The population structure of 251 A. americanum ticks, collected from canines and two white-tailed deer in six Arkansas ecoregions, was examined using DNA sequences of a 247-bp region of the mitochondrial DNA ribosomal RNA 16S gene. Of the 247 nucleotide characters, 26 were variable. Thirty-three haplotypes were identified of which 25 haplotypes occurred once (10%). The most common haplotype was Aa25, occurring in 60% of the samples and found in all six ecoregions. The excess of low frequency haplotypes combined with the overall negative Tajima's D and Fu and Li statistics suggests population expansion. Phylogenetic relationships of the 33 A. americanum haplotypes were constructed with other Amblyomma species and identified A. americanum as a monophyletic species with two groups. The patterns of high nucleotide and haplotype diversity found in this study suggests that the A. americanum population is expanding perhaps due to its ability to survive in a variety of habitats and feed on multiple hosts. Given the gene flow in Arkansas, the spread of acaricide resistance and pathogens may be rapid.

Hosts, distribution and genetic divergence (16S rDNA) of Amblyomma dubitatum (Acari: Ixodidae)

We supply information about hosts and distribution of Amblyomma dubitatum. In addition, we carry out an analysis of genetic divergence among specimens of A. dubitatum from different localities and with respect to other Neotropical Amblyomma species, using sequences of 16S rDNA gene. Although specimens of A. dubitatum were collected on several mammal species as cattle horse, Tapirus terrestris, Mazama gouazoubira, Tayassu pecari, Sus scrofa, Cerdocyon thous, Myocastor coypus, Allouata caraya, Glossophaga soricina and man, most records of immature and adult stages of A. dubitatum were made on Hydrochoerus hydrochaeris, making this rodent the principal host for all parasitic stages of this ticks. Cricetidae rodents (Lundomys molitor, Scapteromys tumidus), opossums (Didelphis albiventris) and vizcacha (Lagostomus maximus) also were recorded as hosts for immature stages. All findings of A. dubitatum correspond to localities of Argentina, Brazil, Paraguay and Uruguay, and they were concentrated in the Biogeographical provinces of Pampa, Chaco, Cerrado, Brazilian Atlantic Forest, Parana Forest and Araucaria angustifolia Forest. The distribution of A. dubitatum is narrower than that of its principal host, therefore environmental variables rather than hosts determine the distributional ranges of this tick. The intraspecific genetic divergence among 16S rDNA sequences of A. dubitatum ticks collected in different localities from Argentina, Brazil and Uruguay was in all cases lower than 0.8%, whereas the differences with the remaining Amblyomma species included in the analysis were always bigger than 6.8%. Thus, the taxonomic status of A. dubitatum along its distribution appears to be certain at the specific level.

Epidemiological survey of canine babesiosis in Makurdi, Nigeria

The prevalence of Babesia canis and their tck vectors was investgated in Makurd 108 dogs were screened for Babesia canis and 208 dogs were examined for tick ectoparasites. 10.2 % o the dogswere positive for Babesia canis infecton. Chi square analysis showed no significant difference in infection rates in male and female dogs (X2 = 2.579, df = 1, P > 005). 75.9 % of dogs examined for ticks were infested with either Rhipicephalus, Boophilus and Amblyomma species or combination ofthe three. The paws were the most preferred site of attachmentfor the tcks. 126 (79.6 %) of the 158 inested dogs had ticks on the paw (X2 = 10.388, df = 4, P > 005). The publc health implications of these findings especially as relates to the increasing incidence and prevalence of dog borne zoonotic infections are discussed.Keywords: Babesia canis, Ticks, Public health risk

Rickettsia africaeInfection in Man after Travel to Ethiopia

To the Editor: The first human case of African tick-bite fever was described in 1992 as occurring in Zimbabwe. The causative agent was identified as a new serotype of the spotted fever group (SFG) rickettsiae and named Rickettsia africae (1). These findings confirmed observations made by Pijper in the 1930s, which suggested that there were 2 different kinds of human SFG rickettsioses in sub-Saharan Africa: Mediterranean spotted fever caused by R. conorii and transmitted by Rhipicephalus species, ticks of dogs, and African tick-bite fever caused by R. africae and transmitted by Amblyomma species, ticks of cattle and wild ungulates. African tick-bite fever has subsequently been diagnosed in patients from several other sub-Saharan countries and also from the West Indies (2,3). In a recent analysis of the spectrum of diseases among returning travelers, tick-borne spotted fever was (after malaria) the second most frequent cause of systemic febrile illness among those returning from sub-Saharan Africa. It occurred more frequently than typhoid fever and dengue fever (4). The following case description reports an infection with R. africae in a man in France who recently returned from Ethiopia. On November 4, 2005, a 62-year-old French man sought care at the Medical Center of the Institut Pasteur in Paris for fever, along with chills, headache, neck and shoulder pain, and fatigue over the previous 4 days. At the onset of these symptoms he had noticed dark nodular lesions on his neck and his left groin followed 2 days later by a slightly painful eruption on his arms and his trunk. He had spent a month in southwest Ethiopia, north of Kelem near the Sudanese border, and returned to France on October 26, 2005. While in Ethiopia, he had assisted with a production of a documentary film about an Ethiopian tribe and had been in contact with cattle in the villages. He had not noticed any tick bites. On physical examination he had a fever of 38°C, a nodular lesion with a central dark crust on his neck, a second lesion on his left inguinal fold (Figure, panel A), and a vesicular eruption on his arms and his trunk (Figure, panel B). Leukocyte count was 3,200, including 1,869 neutrophils and 867 lymphocytes. The platelet level was 174,000/mm3. The C-reactive protein level was 28.3 mg/L. The aspartate aminotransferase level was slightly elevated. The patient was treated with doxycycline 200 mg/day for 1 week for suspected African tick-bite fever. Follow-up showed a quick recovery from his symptoms except for fatigue that persisted for ≈1 month. Figure Inoculation eschar on left inguinal fold (A) and vesicular skin lesion (B) in a traveler recently returned to France from Ethiopia. A commercial immunofluorescence assay for R. conorii and R. typhi immunoglobulin G performed both on an initial blood sample and a second sample taken 1 week later were negative. A blood sample and a biopsy specimen of the inguinal eschar were sent to the National Reference Center of Rickettsiae in Marseille, France. Although cellular culture of both specimens and molecular testing of the blood sample were negative, PCR for the sequences of citrate synthase (GenBank accession no. {type:entrez-nucleotide,attrs:{text:RAU59733,term_id:1389980}}RAU59733, 93.1% homology) and rickettsial OmpA (GenBank accession no. {type:entrez-nucleotide,attrs:{text:RAU83436,term_id:62861416}}RAU83436, 99.3% homology) applied on the skin biopsy detected R. africae and confirmed the diagnosis of African tick-bite fever. From 1969 to 1971, SFG rickettsiae were isolated from Amblyomma spp. ticks collected in Ethiopia. They were regarded as R. conorii or as closely related bacteria (5). Later, more specific tests using western immunoblots with monoclonal antibodies showed that these rickettsiae differed from R. conorii (6). In 1992 SFG rickettsiae isolated from Amblyomma ticks collected in Zimbabwe and from the blood of a patient in Zimbabwe were compared to R. conorii, to other pathogenic SFG rickettsiae, and to a SFG rickettsia isolated from an Amblyomma spp. tick in Ethiopia 20 years before. The SFG rickettsia isolates from Ethiopia were identical to isolates obtained in Zimbabwe from the Amblyomma ticks and the patient’s blood and were different from R. conorii and other pathogenic SFG rickettsiae. This new serotype of SFG rickettsiae was named R. africae (1,7). A recent study confirmed the presence of R. africae in ticks collected in Ethiopia, as well as R. aeschlimanii (8). Thus, evidence of R. africae in Ethiopia has been known for a long time. The geographic distribution of African tick-bite fever is related to the presence of Amblyomma spp. ticks, vectors and reservoirs of R. africae. Consequently African tick-bite fever should also be considered as a possible diagnosis in patients with febrile illness returning from countries where R. africae has been detected in Amblyomma ticks, even if a human infection has not yet been reported (9,10).

PATTERN OF TICK SPATIAL DISTRIBUTION OF A FRAGMENT OF FOREST IN AN URBAN AREA, THROUGH A SURVEY BY CO2 TRAP

ABSTRACT The study of the ixodofauna in fragments of woods in an urban area is important to the knowledge of species of tick and the dynamic among wild and domestic hosts, allowing to subsidize proposals for the conservation of the fauna and the control of zoonoses such as Brazilian spotted fever. To accomplish the survey, CO2 traps were built up in six different sites of the forest, during a oneyear period, totalizing 12 collections. The ixodids were collected by monitoring the traps and the adjacent vegetation during two hours and put in ethanol 70° GL. At the laboratory they were identified under the stereoscopic optics. At the end of a one-year period of study 2.122 ixodids were colleted, being 793 larvae (37,3%) and 1.277 nymphs (57,8%) of the genus Amblyomma and 102 were adults (4,9%) of the Amblyomma species. The most constant species was Amblyomma cajennense, present in 83,33% of the collections (71 specimen) followed by Amblyomma dubitatum, present in 50% (30 specimen), and Amblyomma calcaratum, 8,33% (one specimen). The observations showed that in the observed environment the populations of Ixodidae have an aggregate distribution, possibly because of the aggregate distribution of the resource, in the case wild hosts.

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.

Babesia spp. infection in dogs from rural areas of São Paulo State, Brazil

The status of Babesia spp. infection in dogs from rural areas of São Paulo State, Brazil was studied. For this, 150 animals were examined by blood smears and by PCR; the presence of tick infestation was also investigated. By the blood smear examination, 3 animals (2%) were detected positive and by PCR for Babesia spp. 12 (8%) were positive, with bands visualized in 450 bp. Rhipicephalus sanguineus or Amblyomma spp. were found on 36 (24%) of the 150 dogs. Amblyomma species found were A. cajennense (9/36-25%) and A. ovale (9/36-25%). It was not possible to correlate the presence of R. sanguineus and the infection with Babesia spp. The sequencing of four positive samples demonstrated close identity with B. canis vogeli already characterized in Brazil.

Distribution, hosts, 16S rDNA sequences and phylogenetic position of the Neotropical tickAmblyomma parvum(Acari: Ixodidae)

The hosts, distribution, intraspecific genetic variation and phylogenetic position of Amblyomma parvum (Acari: Ixodidae) have recently been re-assessed. Data on this tick's hosts and distribution were obtained not only from existing literature but also from unpublished records. Sequences of the ticks' mitochondrial 16S ribosomal DNA (rDNA) were used to evaluate genetic variation among specimens of A. parvum from different localities in Argentina and Brazil, and to explore the phylogenetic relationships between this tick and other Amblyomma species. Although several species of domestic and wild mammal act as hosts for adult A. parvum, most collected adults of this species have come from cattle and goats. Caviid rodents of the subfamily Caviinae appear to be the hosts for the immature stages. So far, A. parvum has been detected in 12 Neotropical biogeographical provinces (Chaco, Cerrado, Eastern Central America, Venezuelan Coast, Pantanal, Parana Forest, Caatinga, Chiapas, Venezuelan Llanos, Monte, Western Panamanian Isthmus, and Roraima) but the Chaco province has provided significantly more specimens than any other (P<0.0001). The 16S rDNA sequences showed just 0.0%-1.1% divergence among the Argentinean A. parvum investigated and no more than 0.2% divergence among the Brazilian specimens. The observed divergence between the Argentinean and Brazilian specimens was, however, greater (3.0%-3.7%). Although there is now molecular and morphological evidence to indicate that A. parvum, A. pseudoparvum, A. auricularium and A. pseudoconcolor are members of a natural group, previous subgeneric classifications do not reflect this grouping. The subgeneric status of these tick species therefore needs to be re-evaluated. The 16S-rDNA-based evaluation of divergence indicates that the gene flow between Argentinean and Brazilian 'A. parvum' is very limited and that the Argentinean 'A. parvum' may be a different species to the Brazilian.