Comparative analyses of mitochondrial and nuclear genetic markers for the molecular identification of Rhipicephalus spp.

The genus Rhipicephalus (Acari: Ixodidae) comprises a large number of vectors of pathogens of substantial medical and veterinary concern; however, species identification based solely on morphological features is often challenging. In the present study, genetic distance within selected Rhipicephalus species (i.e., Rhipicephalus bursa, Rhipicephalus guilhoni, Rhipicephalus muhsamae, Rhipicephalus sanguineus sensu lato and Rhipicephalus turanicus), were investigated based on molecular and phylogenetic analyses of fragments of the mitochondrial 16S, 12S and cytochrome c oxidase subunit 1 (cox1) genes, as well as of the whole sequences of the ribosomal internal transcribed spacer-2 (ITS-2) region. Mean values of inter-specific genetic distance (e.g., up to 12.6%, 11.1% and 15.2%), as well as of intra-specific genetic distance (e.g., 0.9%, 0.9% and 1%), calculated using the Kimura-2 parameter substitution model with uniform rates among sites for 16S, 12S and cox1 genes, respectively, confirmed the differentiation of the rhipicephaline species herein examined. The molecular identification was also supported by the distinct separation of species-specific clades inferred from the phylogenetic analyses of all mitochondrial sequences. Conversely, little interspecific divergence was detected amongst ribosomal ITS-2 sequences (i.e., up to 2.8%) for species belonging to the R. sanguineus complex, which resulted in the ambiguous placement of selected R. sanguineus s.l. and R. turanicus sequences in the corresponding phylogenetic tree. Results from this study confirm the suitability of mtDNA markers for the reliable identification of ticks within the Rhipicephalus genus and provide a framework for future studies of taxonomy, speciation history and evolution of this group of ticks

Thelaziosis in Humans, a Zoonotic Infection, Spain, 2011

After Thelazia callipaeda infection in dogs and cats were reported in Spain, a human case of thelaziosis in this country was reported, suggesting zoonotic transmission. The active reproductive status of this nematode in situ indicates that humans are competent hosts for this parasite

Evidence of increasing risk of dorofilarioses in Southen Italy

Given the spread of Aedes albopictus from northern to southern Italy, and the lack of updated data on Dirofilaria infections, this study was carried out to assess the infection risk for dogs and cats in Apulia region. During a 2-year study, 175 A. albopictus female specimens and samples of blood from 427 dogs (309 privately owned dogs and 118 shelter dogs) and 12 cats were collected. All blood samples were subjected to a modified Knott method, to a test for the detection of circulating Dirofilaria immitis antigen, and to a Dirofilaria species-specific real-time PCR for the simultaneous detection of D. immitis and Dirofilaria repens, targeting on partial cytochrome oxidase subunit 1 and internal transcribed spacer-2, respectively. Two abdomen and one thorax pools from A. albopictus were positive for D. immitis, with minimum infection rates of 1.14 and 0.51, respectively, and a probability of a single positive specimen to be infected of P\u2009=\u20090.6 % (95 % confidence interval (CI)\u2009=\u20090.12-1.73). Out of 439 examined subjects, 22 (5.0 %) tested positive for Dirofilaria spp. in at least one diagnostic test. A specific D. immitis infestation rate of 3.5 % was found among the privately owned dogs, while shelter dogs tested positive only for D. repens with a prevalence of 3.4 %; one cat tested molecularly positive for D. immitis. There was a significantly higher rate of positivity among guard dogs for D. immitis (odds ratio, 6.24, 95 % CI, 1.26-25.28; P\u2009<\u20090.05). The increasing risk of D. immitis infection in southern Italy is supported by the noteworthy positivity of A. albopictus populations and the cat. Our data highlight the usefulness to include filarioid infestation in routine diagnosis

A multiplex PCR for the simultaneoous detection of species of filarioids infesting dogs.

The present study reports the applicability of a multiplex PCR for the simultaneous detection and differentiation of common filarioids infecting dogs, i.e., Dirofilaria immitis, Dirofilaria repens, Acanthocheilonema reconditum and Cercopithifilaria sp. Amplicons of different sizes (i.e., 170 bp, 480 bp, 590 bp and 300 bp, respectively) of regions within the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene were amplified on a single-step multiplex PCR using a mix of species-specific forward primers coupled with a single reverse primer. Experiments were carried out by amplifying genomic DNA extracted from blood or skin samples test-positive for microfilariae (mff). The number of mff present in each blood sample was quantified (from 800 to 25,000 mff/ml for A. reconditum and D. repens, respectively) and mixed blood samples were tested for the simultaneous detection of DNA from these mff. Specific amplicons for blood-circulating mff of A. reconditum, D. immitis and D. repens and for those whose adults are localized in skin (i.e., A. reconditum and Cercopithifilaria sp.) were simultaneously detected on agarose gel up to a dilution of 250 mff/ml for D. repens. The specific identity of the amplicons was confirmed by sequencing. The multiplex PCR assay reported herein represents a new tool for the molecular detection and differentiation of canine filarioids in blood and skin samples

Species diversity of dermal microfilariae of the genus Cercopithifilaria infesting dogs in the Mediterranean region

Following the recent description of microfilariae of a Cercopithifilaria sp. in a dog from Sicily, Italy, (herein after referred to as Cercopithifilaria sp. I), numerous skin samples were collected from dogs in the Mediterranean region. In addition to Cercopithifilaria sp. I (185·7±7·2 μm long), microfilariae of 2 other species were identified, namely Cercopithifilaria grassii (651·7±23·6 μm long) and a yet undescribed microfilaria, Cercopithifilaria sp. II (264·4±20·2 μm long, with evident lateral alae). The morphological differentiation among the 3 species of dermal microfilariae was confirmed by differences in cytochrome c oxidase subunit 1 and ribosomal 12S sequences examined (mean level of interspecific pairwise distance of 11·4%, and 17·7%, respectively). Phylogenetic analyses were concordant in clustering these with other sequences of Cercopithifilaria spp. to the exclusion of Dirofilaria spp., Onchocerca spp. and Acanthocheilonema spp. Dermal microfilariae collected (n=132) were morphologically identified as Cercopithifilaria sp. I (n=108, 81·8%), Cercopithifilaria sp. II (n=17, 12·9%), whereas only 7 (5·3%) were identified as C. grassii. Mixed infestations were detected in all sites examined. The great diversity of these neglected filarioids in dogs is of biological interest, considering the complex interactions occurring among hosts, ticks and Cercopithifilaria spp. in different environments

Zoonotic Onchocerca lupi Infection in Dogs, Greece and Portugal, 2011-2012.

Onchocerca lupi infection is reported primarily in symptomatic dogs. We aimed to determine the infection in dogs from areas of Greece and Portugal with reported cases. Of 107 dogs, 9 (8%) were skin snip–positive for the parasite. DNA sequences of parasites in specimens from distinct dog populations differed genetically from those in GenBank