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The aim of this study was to examine the presence of tick-borne rickettsial bacteria in Rhipicephalus sanguineus sensu stricto ticks collected from dogs in the Patagonian region of Argentina. Fourteen stray dogs from Valcheta, Río Negro province, Argentina were examined for the presence of R. sanguineus s.s. ticks. Ninety ticks were collected and identified to species level. DNA was extracted and analysed by conventional PCR assays for the presence of tick-borne bacteria belonging to the genera Anaplasma , Ehrlichia and Rickettsia. Thirty-three tick pools were tested by different PCR assays of which 3 were positive for Anaplasmataceae bacteria. From the 3 Anaplasmataceae positive samples, 2 partial 16S rDNA sequences were generated and belonging to Anaplasma platys , the causative agent of canine cyclic thrombocytopenia. Two tick samples were positive in Rickettsia specific PCR assays and were identified by phylogenetic analysis as Rickettsia massiliae , a member of the spotted fever group rickettsiae. The results of this study demonstrate the molecular detection of 2 rickettsial bacteria in R. sanguineus s.s. in a region of Argentina where no data were available so far. [ABSTRACT FROM AUTHOR]

The aim of this work was to generate knowledge on ecological aspects of Amblyomma sculptumin Argentina, such as seasonal dynamics, geographical range size, hosts, genetic diversity and phylogeography. Adult and immature A. sculptumticks were collected in different localities of Argentina to know the geographical range size and hosts. The genetic diversity of this tick was studied through analyses of 16S rDNA sequences. To describe the seasonal dynamics, free-living ticks were monthly collected from October 2013 to October 2015. A. sculptumshows a marked ecological preference for Chaco Húmedo eco-region and “Albardones” forest of the great rivers in the wetlands in the Chaco Biogeographical Province, and for Selvas Pedemontanas and Selva Montana in the Yungas Biogeographical Province. This species has low host specificity, and it has large wild and domestic mammals as principal hosts to both immature and adult stages. Amblyomma sculptumis characterized by a one-year life cycle. Larvae peak in early winter, nymphs peaked during mid-spring, and adults during late summer and mid-summer. The genetic divergence was low and the total genetic variability was attributable to differences among populations. This fact could be associated to stochastics process linked to micro-habitat variations that could produce a partial restriction to gene flow among populations. The geographic regions do not contribute much to explain the A. sculptumpopulation genetic structure, with an ancestral haplotype present in most populations, which gives rise to the rest of the haplotypes denoting a rapid population expansion.

This work was performed to evaluate the presence of Borreliain different populations of Ixodes pararicinusfrom northwestern Argentina (Jujuy, Salta and Tucumán provinces). Questing adults and nymphs of I. pararicinuswere collected from vegetation, and I. pararicinusnymphs were also collected on birds. Eighty-two ticks were tested for Borreliapresence by PCR targeting the gene flagellin and the rrfA-rrlBintergenic spacer region. Pools of ticks positive to Borreliawere formed by two nymphs collected on Turdus rufiventrisin Tucumán, one nymph collected on Syndactyla rufosuperciliatain Jujuy, one nymph collected on Turdus nigricepsin Tucumán, three nymphs collected on T. nigricepsin Tucumán, and two females collected from vegetation in Salta. Two haplotypes of Borreliasp. belonging to the Borrelia burgdorferisensu lato complex were found. One of them is closely related to the haplotypes of Borreliagenospecies previously reported in I. aragaoifrom Uruguay (haplotypes D and E) and in I. pararicinusfrom Jujuy Province in Argentina. The second haplotype (detected in the sample of Salta) is closely related to the haplotypes A, B and C associated with I. aragaoifrom Uruguay. All these results suggest that the presence of B. burgdorferis.l. genospecies in I. pararicinusticks is widespread along the entire distribution of this tick species in northwestern Argentina. However, the Borreliapresence in I. pararicinuscannot be directly assumed as a phenomenon of medical relevance, because Ixodesticks are not relevant as human parasites in South America, and none of the two Borreliagenospecies detected in this work is related to any of the Borreliagenospecies currently known to be pathogenic to humans.

The aim of this study is to determine if there is circulation of microorganisms of the genus Ehrlichiain opossums Didelphis albiventrisand their ticks from the Humid Chaco in Argentina. Blood samples of 15 specimens of the opossum D. albiventriswere analysed. Immature stages of the ticks Amblyomma ovale(Larvae=26; Nymphs=10), Amblyomma sculptum(Larvae=86; Nymphs=6) and Ornithodorossp. cf. O. mimon(Larvae=90) were also analyzed. DNA was extracted individually from blood samples and ticks. Molecular detection of Ehrlichiaagents was performed targeting two different loci: 16S rRNA and dsb gen. The phylogenetic analyses showed that the Ehrlichiasp. detected in D. albiventrisin this study is identical to Ehrlichiasp. strain Natal previously detected in two marsupials from Brazil. Furthermore, a new Ehrlichia strain was amplified from an A. ovalenymph (named as Ehrlichiasp. strain El Bagual) which is phylogenetically closely related to a strain of Ehrlichiasp. detected in Bradypus tridactylusin Brazil. The findings of the current study represent the first report of these two strains of Ehrlichiafor Argentina, showing that the diversity of Ehrlichiaspp. is greater than previously assumed. Further studies should determine the epidemiological relevance of these findings.

Rhipicephalus secundusis reestablished as a valid tick name within the Rhipicephalus sanguineusgroup and removed from the synonymy list of Rhipicephalus turanicus.Morphological re-description of both male and female of R. secundusand the analysis of its phylogenetic position based on mitochondrial DNA sequences are presented. The morphological re-description was made with tick specimens collected on goat in Israel. The phylogenetic analyses showed that R. secundusbelong to a different clade from those formed by R. turanicussensu stricto (s.s.) and R sanguineuss.s., and by other taxa from the R. sanguineusgroup. Rhipicephalus secundusis morphologically related to R. turanicus, but the scutal punctation pattern of both male and female allows the morphological differentiation between R. secundusand R. turanicus, punctations being clearly more numerous and larger in the latter. Both male and female of R. secunduscan be differentiated from those of R. sanguineuss.s. by the shape of the spiracular plate. In males, the dorsal prolongation of the spiracular plate is equal to the breadth of the adjacent festoon in R. secundus, while it is narrower than the breadth of the adjacent festoon in R. sanguineuss.s. The dorsal prolongation of the spiracular plate in the female of R. secundusis wider than in the female of R. sanguineuss.s. The genital apertures of the females of R. secundusand R. sanguineusare both U-shaped, but in R. sanguineuss.s. it is broader than in R. secundus.Considering the results obtained in this study, it can be stated that R. secundusis present at least in Israel, Palestinian Territories, Turkey, Albania and southern Italy, but it is necessary to carry out additional studies to determine the geographical range and host usage of this species.

•Forty-two horses (Equus caballus) from Corrientes City, Argentina were sampled.•Eighty-one percent of the horses (34 animales) were tested positive to the presence of Theileria equi.•Phylogenetic analysis of an obtained 18S rDNA complete sequence from one strain resulted in the identification of this sample as T. equisensu stricto.•This study presents the first molecular detection and characterization of T. equiby the complete 18S rDNA sequence in Argentina.

The aim of this work was to evaluate the presence of Borreliainfection in Ixodessp. cf. Ixodes affinisticks from Argentina. Specimens of Ixodessp. cf. I. affiniswere collected on vegetation and birds in five locations belonging the most humid part of the Chaco Biogeographic Province. Specimens were tested for Borreliainfection by nested-PCR targeting the flaB gene and the rrfA-rrlBintergenic spacer region (IGS), sequenced and phylogenetically analyzed. A total of 48 Ixodessp. cf. I. affinis(12 questing adults from vegetation and 20 nymphs and 16 larvae on nine bird species: Arremon flavirostris, Basileuterus culicivorus, Campylorhamphus trochilirostris, Myiothlypis leucoblephara, Tachyphonus rufus, Thlypopsis sordida, Turdus amaurochalinus, Turdus rufiventrisand Troglodytes aedon) were collected. Twelve adults, 14 nymphs and 11 larvae (3 individually and 8 in 3 pools) were analyzed. Partial sequences were detected in 6 adults, 11 nymphs and 4 larvae (2 individual and 2 pools). Phylogenetically, the Borreliafound in Ixodessp. cf. I. affinisbelongs to the B. burgdorferisensu lato (s. l.) complex. The partial sequences obtained from the borrelian gene flaB and IGS were associated to two groups formed by sequences previously detected in Ixodes fuscipes, Ixodes longiscutatusand Ixodes pararicinusfrom the Southern Cone of America in northern Argentina, southern Brazil and Uruguay. The results of this work suggest that the haplotypes of B. burgdorferis. l. complex detected in the three species of the I. ricinuscomplex distributed in the Southern Cone of America are related and widely distributed.