Biological compatibility between two temperate lineages of brown dog ticks, Rhipicephalus sanguineus (sensu lato).

BACKGROUND: The brown dog tick Rhipicephalus sanguineus (sensu stricto) is reputed to be the most widespread tick of domestic dogs worldwide and has also been implicated in the transmission of many pathogens to dogs and humans. For more than two centuries, Rh. sanguineus (s.s.) was regarded as a single taxon, even considering its poor original description and the inexistence of a type specimen. However, genetic and crossbreeding experiments have indicated the existence of at least two distinct taxa within this name: the so-called "temperate" and "tropical" lineages of Rh. sanguineus (sensu lato). Recent genetic studies have also demonstrated the existence of additional lineages of Rh. sanguineus (s.l.) in Europe and Asia. Herein, we assessed the biological compatibility between two lineages of Rh. sanguineus (s.l.) found in southern Europe, namely Rhipicephalus sp. I (from Italy) and Rhipicephalus sp. II (from Portugal). METHODS: Ticks morphologically identified as Rh. sanguineus (s.l.) were collected in southern Portugal and southern Italy. Tick colonies were established and crossbreeding experiments conducted. Morphological, biological and genetic analyses were conducted. RESULTS: Crossbreeding experiments confirmed that ticks from the two studied lineages were able to mate and generate fertile hybrids. Hybrid adult ticks always presented the same genotype of the mother, confirming maternal inheritance of mtDNA. However, larvae and nymphs originated from Rhipicephalus sp. I females presented mtDNA genotype of either Rhipicephalus sp. I or Rhipicephalus sp. II, suggesting the occurrence of paternal inheritance or mitochondrial heteroplasmy. While biologically compatible, these lineages are distinct genetically and phenotypically. CONCLUSIONS: The temperate lineages of Rh. sanguineus (s.l.) studied herein are biologically compatible and genetic data obtained from both pure and hybrid lines indicate the occurrence of paternal inheritance or mitochondrial heteroplasmy. This study opens new research avenues and raises question regarding the usefulness of genetic data and crossbreeding experiments as criteria for the definition of cryptic species in ticks.

Morphological and genetic diversity of Rhipicephalus sanguineus sensu lato from the New and Old Worlds.

BACKGROUND: The taxonomic status of the brown dog tick (Rhipicephalus sanguineus sensu stricto), which has long been regarded as the most widespread tick worldwide and a vector of many pathogens to dogs and humans, is currently under dispute. METHODS: We conducted a comprehensive morphological and genetic study of 278 representative specimens, which belonged to different species (i.e., Rhipicephalus bursa, R. guilhoni, R. microplus, R. muhsamae, R. pusillus, R. sanguineus sensu lato, and R. turanicus) collected from Europe, Asia, Americas, and Oceania. After detailed morphological examination, ticks were molecularly processed for the analysis of partial mitochondrial (16S rDNA, 12S rDNA, and cox1) gene sequences. RESULTS: In addition to R. sanguineus s.l. and R. turanicus, three different operational taxonomic units (namely, R. sp. I, R. sp. II, and R. sp. III) were found on dogs. These operational taxonomical units were morphologically and genetically different from R. sanguineus s.l. and R. turanicus. Ticks identified as R. sanguineus s.l., which corresponds to the so-called "tropical species" (= northern lineage), were found in all continents and genetically it represents a sister group of R. guilhoni. R. turanicus was found on a wide range of hosts in Italy and also on dogs in Greece. CONCLUSIONS: The tropical species and the temperate species (= southern lineage) are paraphyletic groups. The occurrence of R. turanicus in the Mediterranean region is confirmed. A consensual re-description of R. sanguineus s.s. and R. turanicus will be necessary to solve the taxonomic problems within the so-called R. sanguineus group.

Genetic variability and phospholipase production of Malassezia pachydermatis isolated from dogs with diverse grades of skin lesions.

Little detailed information is available on the association of Malassezia pachydermatis genotypes and the extent of skin damage that they cause. In the present study, isolates of M. pachydermatis, recovered from the skin of healthy dogs and dogs with dermatitis in Brazil, were characterized on the basis of partial sequencing of the large subunit (LSU), first internal transcribed spacer (ITS-1) and chitin synthase 2 gene (chs-2). The determination of phospholipase production was also included in the investigations. The severity of lesions and hyperpigmentation of dogs with skin disease were evaluated. For each locus, two main sequence types were designated as genotypes A and C. Two other minor sequence types (A2(I)-C2(I)) were also recorded and defined for the ITS-1. Genotype A isolates were the most prevalent, being recovered from healthy and diseased animals. No significant difference was detected among genotypes or ITS-1 sequence types and grades of skin damage or hyperpigmentation in the dogs with skin lesions. The number of M. pachydermatis isolates that produced phospholipase was statistically higher for diseased dogs than for strains found in healthy animals. The present study reveals that multiple genetic variants of M. pachydermatis occur in dogs and that the distribution patterns of particular genotypes on the skin of dogs in Brazil might be related to environmental and ecological factors which maintain distinctive genotype assemblages in specific geographical areas.

Estudio epidemiológico de seropositividad al virus HIV en varones de 18 años República Argentina, 1987-1990: informe preliminar 1987 / Epidemiologic study of seropositivity to viruses HIV in 18-year-old males Argentine Republic, 1987-1990: preliminary report

El 50% de todos los jóvenes de 18 años del país se presenta anualmente a un exmen médico para el Servicio Militar (realizado como una obligación con base legal). Este hecho permitió el estudio seroepidemiológico de aquellos que presentaron algún "factor de riesgo" entre las personas presentadas (114.375). El objetivo consistió en estudiar la tasa de prevalencia se seropositividad del HIV, su asociación con ciertos factores como "convivientes", "enfermedades venéreas", "prisión", etc., e iniciar el registro de aquellos que presentaron algún "factor de riesgo", tanto HIV positivos como negativos, para un seguimiento ulterior

Estudio epidemiológico de seropositividad al virus HIV en varones de 18 años República Argentina, 1987-1990: informe preliminar 1987 / Epidemiologic study of seropositivity to viruses HIV in 18-year-old males Argentine Republic, 1987-1990: preliminary report

El 50% de todos los jóvenes de 18 años del país se presenta anualmente a un exmen médico para el Servicio Militar (realizado como una obligación con base legal). Este hecho permitió el estudio seroepidemiológico de aquellos que presentaron algún "factor de riesgo" entre las personas presentadas (114.375). El objetivo consistió en estudiar la tasa de prevalencia se seropositividad del HIV, su asociación con ciertos factores como "convivientes", "enfermedades venéreas", "prisión", etc., e iniciar el registro de aquellos que presentaron algún "factor de riesgo", tanto HIV positivos como negativos, para un seguimiento ulterior (AU)

IgM treponema pallidum hemoaglutinación (IgMTPHA) / IgM treponema pallidum hemagglutination

Considerando la importancia de la detección y cuantificación de la IgM sifilítica, hemos desarrollado en base a referencias mundiales, una técnica de simple ejecución. Las mismas policubetas en U con que se realiza la TPHA (MHATP) son incubadas con anti IgM en PBS. Luego del lavado y secado, se enfrentan los pocillos marcados con anti IgM con diluciones del suero del paciente. Se incuba una hora a 37-C. se elimina por lavados el suero y se realiza sobre la IgM sifilítica absorbida, la clásica reacción de hemoaglutinación. La IgMTPHA fue controlada con diluciones geométricas de sueros previamente reactivos con la TPHA de pacientes con Sífilis temprana, tardía y recién nacidos de madres con serología específica Reactiva. Entendemos que la IgMTPH abre un panorama de aplicación clínica y terapéutica en pacientes con Sífilis tardía (latente o serológica, neuro, oto y cardiolues) y en Sífilis de la embarazada y congénita

IgM treponema pallidum hemoaglutinación (IgMTPHA) / IgM treponema pallidum hemagglutination

Considerando la importancia de la detección y cuantificación de la IgM sifilítica, hemos desarrollado en base a referencias mundiales, una técnica de simple ejecución. Las mismas policubetas en U con que se realiza la TPHA (MHATP) son incubadas con anti IgM en PBS. Luego del lavado y secado, se enfrentan los pocillos marcados con anti IgM con diluciones del suero del paciente. Se incuba una hora a 37-C. se elimina por lavados el suero y se realiza sobre la IgM sifilítica absorbida, la clásica reacción de hemoaglutinación. La IgMTPHA fue controlada con diluciones geométricas de sueros previamente reactivos con la TPHA de pacientes con Sífilis temprana, tardía y recién nacidos de madres con serología específica Reactiva. Entendemos que la IgMTPH abre un panorama de aplicación clínica y terapéutica en pacientes con Sífilis tardía (latente o serológica, neuro, oto y cardiolues) y en Sífilis de la embarazada y congénita (AU)