Management strategies to minimize the use of synthetic chemical acaricides in the control of the cattle tick Rhipicephalus (Boophilus) microplus (Canestrini, 1888) in an area highly favourable for its development in Argentina.

The aim of this work was to test the efficacy of winter-spring control strategies against Rhipicephalus (Boophilus) microplus (Canestrini, 1888) (Ixodida: Ixodidae) in an area highly favourable for its development in Argentina. Control schemes using three or four annual applications of synthetic acaricides were evaluated. Furthermore, the dynamics of the non-parasitic phases of R. microplus were analysed to provide a framework for the application of pasture spelling as a tool for tick control. The treatment schemes provided appropriate levels of efficacy against R. microplus and also prevented the occurrence of the major peak in abundance of this tick in autumn. A significant overall effect against R. microplus can be achieved when the control strategies tested in this study are applied within the area most ecologically favourable for this tick in Argentina. Analysis of the dynamics of the non-parasitic phase of R. microplus indicates that the spelling period required to achieve a significant reduction of larvae in pastures fluctuates between 12 and 17 weeks if spelling is initiated in spring or early summer, but between 20 and 28 weeks if spelling is started in late summer, autumn or winter.

Efficacy of winter-spring strategic control against Rhipicephalus (Boophilus) microplus infestations on cattle in an area with ecological conditions highly favourable for the tick in northeast Argentina.

This work was performed to test the efficacy of winter-spring control strategies against Rhipicephalus (Boophilus) microplus (Ixodida: Ixodidae) infestations on cattle in the area ecologically most favourable for the development of this tick in Argentina. Two control schemes using three and four annual applications of acaricides, respectively, were evaluated. Animals in Group 1 were treated with ivermectin 3.15% on day 0, fluazuron on day 34, and fipronil on day 85. Animals in Group 2 were treated with ivermectin 3.15% on day 0, fluazuron on day 34, flumethrin on day 85, and fipronil on day 114. Animals in Group 3 represented the control group. Both treatment schemes provided appropriate levels of efficacy against R. microplus and also prevented the occurrence of the major peak in the frequency of this tick in autumn. The two treatment schemes were similar in terms of efficacy and thus the addition of a fourth treatment does not seem to confer any further advantage. The results of this work indicate that these strategic control methods provide appropriate levels of control against R. microplus.

Ecological characterization of a tick community across a landscape gradient exhibiting differential anthropogenic disturbance in the Atlantic Forest ecoregion in Argentina.

An ecological analysis of a tick (Ixodida: Ixodidae) community across a landscape gradient presenting differential anthropogenic disturbance in the Atlantic Forest ecoregion in Argentina was performed. Ticks were collected from vegetation and hosts between September 2014 and August 2016. A total of 12 697 free-living ticks and 3347 specimens from hosts were collected, including 317 ticks infesting humans. The values obtained show considerable species diversity in the forest environment accompanied by low equitability. The similarity index derived from a comparison of forest and agricultural environments was higher than that calculated by comparing forest and urban environments. The data suggest that although a cycle of one generation per year is apparent in some species, more than one cohort may co-exist within the populations of some of these species. Well-marked patterns of the seasonal distribution of free-living tick species emerged in environments with no anthropic modification. The results indicate that forest environments are more suitable habitats than agricultural and urban environments for many species of native tick, but are unsuitable for exotic species that have successfully established in environments that have been modified by man.

Population dynamics of the cattle tick Rhipicephalus (Boophilus) microplus in a subtropical subhumid region of Argentina for use in the design of control strategies.

The population dynamics of Rhipicephalus microplus (Ixodida: Ixodidae) in northwest Argentina was analysed to support the design of strategic methods for its control. Both parasitic and non-parasitic phases were studied. The seasonal activity of R. microplus in its parasitic phase was characterized by three peaks in abundance: the first in mid-late spring; the second in summer, and the third in autumn. The non-parasitic phase of R. microplus was characterized by a long total non-parasitic period observed after exposures of females from mid-summer to early autumn, a short total non-parasitic period observed after exposures of females from late winter to late spring, a short period of larval longevity in early and mid-summer, and no hatch of the eggs produced by females exposed in mid- and late autumn and winter. Treatments of cattle administered during the period from late winter to late spring will act on small cohorts of R. microplus, preventing the emergence of larger generations in summer and autumn. A 17-week spelling period starting in late spring and early summer will be necessary to achieve optimal control of R. microplus free-living larvae. If spelling begins in mid- or late summer or in autumn, the required period will be 26-27 weeks.

Ecology and genetic variation of Amblyomma tonelliae in Argentina.

The ecology of Amblyomma tonelliae (Ixodida: Ixodidae), including its seasonal distribution and the development periods of each stage, was investigated during a study carried out over two consecutive years in northwestern Argentina. In addition, the genetic variation of this tick was studied through analyses of 16S rDNA sequences. Amblyomma tonelliae has a 1-year lifecycle characterized by a long pre-moult period in larvae with no development of morphogenetic diapause. Larvae peak in abundance during late autumn and early winter; nymphs peak in abundance in spring, and adults do so from late spring to early summer. Amblyomma tonelliae shows a marked ecological preference for the driest areas of the Chaco ecoregion. In analyses of 16S rDNA sequences in genes from different populations of A. tonelliae, values for nucleotide diversity and the average number of nucleotide differences showed genetic diversity within this species to be low. No significant differences were found in comparisons among populations.

Sarcoidosis cutánea / Cutaneous sarcoidosis

Presentamos el caso de una paciente de sexo femenino, de 50 años de edad, quien desarrolló sarcoidosis cutánea pura, sin hallazgos hasta la fecha de compromiso sistémico, demostrando buena respuesta al tratamiento con córticoesteroides sistémicos.

We report the case of a female patient, aged 50, who developed cutaneous sarcoidosis pure, without finding so far, systemic involvement, demonstrating good response to treatment with systemic corticosteroids.

Sarcoidosis cutánea / Cutaneous sarcoidosis

Presentamos el caso de una paciente de sexo femenino, de 50 años de edad, quien desarrolló sarcoidosis cutánea pura, sin hallazgos hasta la fecha de compromiso sistémico, demostrando buena respuesta al tratamiento con córticoesteroides sistémicos.(AU)

We report the case of a female patient, aged 50, who developed cutaneous sarcoidosis pure, without finding so far, systemic involvement, demonstrating good response to treatment with systemic corticosteroids.(AU)

A meta-analysis of host specificity in Neotropical hard ticks (Acari: Ixodidae).

Host specificity of Neotropical hard ticks (Acari: Ixodidae) was analyzed by using the number of hosts species for each tick species and the index of host specificity S(TD)*, which integrates phylogenetic and ecological information. The analyses were based on 4172 records of hard ticks collected from wild and domestic tetrapods. Most tick species included in this study were associated with three to 20 host species. No tick species has been associated either with a single species or with a single genus of host. It was found that the number of host species is sensitive to sampling effort, but not the S(TD)*. The most frequent values of S(TD)* were between 2.5 and 3.5, which shows that the host species more frequently used by Neotropical hard tick species belong to different families or different orders. Immature stages tend to use a broader taxonomic range of hosts than adults, and the interpretation of both measures of host specificity used in this study led to the conclusion that the impact of non-endemic hosts does not alter the patterns of host specificity in Neotropical hard ticks. The index S(TD)* showed that a high proportion of tick species has phylogenetically unrelated species as principal hosts. The conclusion reached in this work indicates that strict host specificity is not common among Neotropical hard ticks and suggests that the influence of tick ecology and evolution of habitat specificity, tick generation time, phenology, time spent off the host and the type of life-cycle could be more important than hosts species.

Ornithodoros peruvianus Kohls, Clifford & Jones (Ixodoidea: Argasidae) in Chile: a tentative diagnosis.

Three argasid tick larvae were collected on April 2, 2010, from a common vampire bat, Desmodus rotundus, captured in the Parque Nacional Pan de Azúcar (26°09' S, 70°41' W), Region of Atacama, Chile. The larvae were diagnosed as Ornithodoros, and further comparative analysis showed them to be Ornithodoros peruvianus Kohls, Clifford & Jones or a species close to it. Phylogenetic analysis based on 16S mitochondrial rRNA gene sequences of Ornithodoros species plus four Argas species was carried out to clarify the taxonomic position of the larvae. This is the first finding of ticks parasitizing D. rotundus in Chile.

Developmental changes in salivary glands of nymphs and adults of the spinose ear tick Otobius megnini.

Otobius megnini has an autogenous 1 host life cycle, where larvae and nymphs stay attached inside the ear canal for long periods, but the adult tick is free living and can lay several egg batches without feeding. In order to obtain information about anatomical structures involved in this particular life cycle, nymphs and adults of O. megnini were dissected and salivary gland images were obtained in situ with the use of scanning electronic microscopy. Measurements of salivary alveoli were obtained with the use of ImageJ 1.40 g software. In the nymphs, the Type I alveoli are relatively small (mean diameter: 19.6 µm) compared with those of the adults (mean: 43.4 µm) and other soft ticks in the literature. Type II alveoli in nymphs are similar (mean: 82.6 µm) to previously described alveoli in adult soft ticks. In contrast, the adults of O. megnini Type II alveoli are smaller (mean: 36.8 µm) and have a wrinkled surface. These findings provide more evidence that Type I alveoli take part in absorption of moisture during the free-living tick stages.

Occurrence of Ornithodoros brasiliensis Aragão (Acari: Argasidae) in São Francisco de Paula, RS, Southern Brazil.

There have been no reports of the endemic Ornithodoros brasiliensis (Aragão) in Rio Grande do Sul, southern Brazil, since the 1950s. In January 2007, 21 O. brasiliensis ticks were collected in a rural area named "Cruzinha" in the municipality of São Francisco de Paula, RS, and another population was sampled later that year (October) in Vargem do Cedro, another rural area of São Francisco de Paula, following reports of human parasitism by ticks. The reappearance of this tick is a reason for concern in terms of public health.

Finding of an ixodid tick inside a late Holocene owl pellet from northwestern Argentina.

In the present study, we report the earliest record of Ixodes sigelos from the late Holocene in Argentina. The tick was recovered from an owl pellet collected within a small mammal sequence in Las Máscaras Cave, Catamarca, Argentina (27 degrees 01'12S'', 66 degrees 44'37''W) and dated at 990 + or - 35 cal yr. Based on bones also present in the pellet, the tick most-likely parasitized a rodent, identified as an Eligmodontia sp., which had been ingested by the owl.

Seasonal distribution of larvae and nymphs of Amblyomma tigrinum Koch, 1844 (Acari: Ixodidae).

The seasonality of immature stages of Amblyomma tigrinum was studied in an area of the Chaco phytogeographical province in Córdoba, Argentina by monthly collection of larvae from ground feeding birds and Sigmodontinae rodents, and nymphs from Caviidae rodents from May 2005 to April 2007. An apparent peak of abundance was found from December to May but differences with other months of the year were not significant (P>0.05). These and previous results suggest that the parasitic stages of A. trigrinum are active throughout the year and has more than one generation per year at the study site. Its life cycle appears to be regulated by temperature with no occurrence of diapause.

Difficulties to control natural infestation with Otobius megnini (Acari: Argasidae) nymphs in cattle with systemic biocides.

A study was carried out to determine the efficacy of topical eprinomectin against nymphal infestation of Otobius megnini in cattle, where a group of 14 individuals were treated with a dose of 0.5mg/per kg of body weight applied on the dorsal midline, and a group of 14 individuals remained as control. Tick burdens between treated and control groups showed no statistically significant differences (P>0.05), and the mortality of the nymphs was similar in both groups (P: 0.828). All females obtained from nymphs of both groups were able to copulate with males from the corresponding group and laid eggs that produced visually normal larvae. The failure of eprinomectin and other biocides applied per os or by injection to control nymphs of O. megnini in cattle indicate that sanitary measures and applications of biocides into the ears would represent the most reasonable approach to control of this tick on cattle.

Field and laboratory studies in a Neotropical population of the spinose ear tick, Otobius megnini.

One ear of each of five cows on a property close to Dean Funes, province of Córdoba, Argentina, was inspected monthly from December 2004 to November 2006 to determine the presence of Otobius megnini (Dugès) and to ascertain its seasonality. Ticks were collected to study the biological parameters of larvae, nymphs and adult ticks. Groups of nymphs were also maintained at three different photoperiods at 25 degrees C. The abundance of immature stages was greatest during January-April and August-October in the first and second years of the study, respectively. No larvae successfully moulted. Nymphs weighing < 17 mg also failed to moult, but 89% of heavier nymphs moulted into adults. Nymphs moulting to males weighed less (49.5 +/- 16.09 mg) than nymphs moulting to females (98.1 +/- 34.08 mg). The pre-moult period was similar for nymphs moulting to either sex and significantly longer (P < 0.01) for female nymphs maintained at 25 degrees C compared with nymphs kept at 27 degrees C. No effect of photoperiod on the pre-moult periods of nymphs was detected. Female ticks produced a mean of 7.0 +/- 1.94 egg batches after a preoviposition period of 16.4 +/- 8.41 days for the first batch. The mean oviposition period was 61 +/- 20.8 days and the duration of oviposition for each batch varied from 1 to 6 days. The mean number of eggs per batch was 93.1 +/- 87.53. The minimum incubation period for the first egg batch was 13.6 +/- 2.77 days. The total number of eggs laid by each female was 651.6 +/- 288.90. Parthenogenesis was not observed. The reproductive efficiency index (REI) (number of eggs laid/weight of female in mg) was 5.5 +/- 1.26. Pearson's correlations showed a significant direct relationship between the weight of the female and number of eggs laid (P < 0.01) and REI (P < 0.05). Several of the biological values presented above for the tick population from the Neotropical zoogeographic region showed marked differences to equivalent values for O. megnini populations from the U.S.A. (Nearctic) and India (Oriental). Nevertheless, the only two sequences of 16S rDNA deposited in GenBank from ticks originating in Argentina and allegedly in the U.S.A. indicate that they are conspecific (99.8% agreement). We tentatively consider the biological differences among populations of this tick species to represent adaptations for survival at different conditions.

Pustulosis exantemática aguda generalizada asociada a Epstein Barr: A propósito de un caso / Acute generalized exanthematous pustulosis associated to Epstein Barr: A propose of a case

Acute generalized exanthematous pustulosis (AGEP) is a rare skin eruption most commonly caused by medications. It is characterized by an acute eruption of sterile pustules and it is accompanied by an episode of fever, which regresses a few days after discontinuation of the drug that caused the condition. We report a case 23 year-old woman without history of psoriasis, that consults for fever and an acute generalized pustular eruption after amoxicillin, with clavulanic acid administration in a mononucleosis infection context, which resolved spontaneously. The microbiologic culture was negative for pathogenic germens.

La pustulosis exantemática aguda generalizada (PEAG) es una rara afección de hipersensibilidad, inducida principalmente por drogas y se manifiesta por una erupción aguda de pústulas estériles, acompañada de fiebre, que regresa en pocos días luego de discontinuar el fármaco causante. Se comunica el caso de una paciente de 23 años de edad, sin antecedentes de psoriasis que consulta por fiebre y una erupción pustulosa generalizada, asociada a la ingesta previa de amoxicilina y ácido clavulánico en el contexto de una mononucleosis infecciosa, con resolución espontánea del cuadro. El cultivo microbiológico no objetivó gérmenes patógenos.

The ornithodoros (Alectorobius) talaje species group (Acari: Ixodida: Argasidae): description of Ornithodoros (Alectorobius) rioplatensis n. sp. from southern South America.

A new species of argasid tick, Ornithodoros (Alectorobius) rioplatensis Venzal, Estrada-Peña, & Mangold, is described from larval and adult specimens collected in Uruguay. Further specimens from Argentina, Paraguay, and Chile are ascribed to the new species. Key distinguishing characters of larvae of the species are the number of pairs of dorsal setae (19-20 but typically 20 in O. rioplatensis, compared with 16-17 but typically 17 in O. puertoricensis and O. talaje), and the length of the hypostome, which is clearly longer in O. rioplatensis than in O. talaje. Morphological details of the adults of these species are inadequate for taxonomic purposes. The genetic distance between O. puertoricensis and O. rioplatensis, based on 16S rDNA sequencing, is approximately 12.7%. Variability in some morphological features, using multivariate morphometric discrimination to assess congruence between populations, was examined among larval specimens of O. talaje and O. puertoricensis collected from the United States, and Central and South America. Larval specimens of O. talaje from Guatemala (near the type locality of the species) were morphologically different from Mexican and southern U.S. populations originally described as O. talaje. In the absence of DNA data for these populations, and because of inadequate statistical discrimination among body characters, we prefer to refer to the Mexican and U.S. material as O. nr. talaje until further analysis of population variability is conducted using an adequate sample size.

Progresión a necrólisis epidérmica tóxica por uso de lamotrigina: A propósito de un caso / Progression to toxic epidermal necrolysis by using lamotrigina: In connection of a case

El Síndrome de Stevens Johnson (SSJ), el Síndrome de Superposición (SSJ/ NET) y la Necrólisis Epidérmica Tóxica (NET) son formas clínicas cutáneo-mucosas graves, desencadenadas por fármacos y muy frecuentemente por anticonvulsivantes. Comunicamos el caso de una paciente medicada por su epilepsia, quién presentó un cuadro incipiente de SSJ empeorando rápidamente hasta derivar en la NET. A pesar de la gravedad, la paciente respondió satisfactoriamente a altas dosis de corticoides sistémicos desde el comienzo y por las medidas de soporte del equipo médico multidisciplinario del hospital.

The Stevens Johnson Syndrome, the Overlape Syndrome (SSJ / NET), and the Toxic Epidermal Necrolysis are clinical cutaneous mucouse forms due to drugs administration and most frequently due caused by antiepileptic. We communicate the case of a patient treated with lamotrigina for epilepsy, who presented an incipient case of Stevens Johnson Syndrome, worsened rapidly causing a Toxic Epidermal Necrolysis. Nevertheless, the patient gained a satisfactory answer due to high doses of corticoids, which were given from the beginning as well as the measures and the support of the whole medical team of the hospital.

Failure of ivermectin and eprinomectin to control Amblyomma parvum in goats: characterization of acaricidal activity and drug pharmacokinetic disposition.

The therapeutic efficacies of ivermectin (subcutaneous injection) and eprinomectin (topical treatment) given at two different dosage levels to goats naturally infested with Amblyomma parvum were assessed. Treatments included subcutaneous injection of ivermectin at 0.2 and 0.4mg/kg and extra-label pour-on administration of eprinomectin at 0.5 and 1mg/kgb.w. Ivermectin and eprinomectin failed to control Amblyomma parvum on goats. Treatment with ivermectin resulted in a low number of engorged female ticks in relation to untreated control goats and, at the highest dose rate (0.4mg/kg), the female engorgement weights were significantly lower and the pre-oviposition period significantly longer than those observed in ticks recovered from untreated control goats. The tick efficacy assessment was complemented in a separate group of tick-free goats with a pharmacokinetic characterization of eprinomectin (topically administered at 0.5, 1.0 and 1.5mg/kg) and ivermectin (subcutaneous treatment given at (0.2 and 0.4mg/kg) in goats. Heparinized blood samples were taken between 0 and 21 days post-treatment. Higher and more persistent drug plasma concentrations were recovered after the subcutaneous treatment with ivermectin compared to those obtained for eprinomectin topically administered. The understanding of the relationship among the pattern of drug absorption, the kinetic disposition and the resultant clinical efficacy is relevant to improve the poor performance observed for ivermectin and eprinomectin against A. parvum on goats.