Density and behavior of capybara (Hydrochoerus hydrochaeris) ticks (Acari: Ixodidae) Amblyomma sculptum and Amblyomma dubitatum with notes on Rickettsia bellii infection: Assessing human exposure risk.

In several urban and peri­urban areas of Brazil, populations of Amblyomma sculptum and Amblyomma dubitatum ticks are maintained by capybaras (Hydrochoerus hydrochaeris). In some of these areas, this host and these tick species are associated with Brazilian spotted fever (BSF), a lethal human disease caused by the bacterium Rickettsia rickettsii. In this work, we evaluated the risk of human exposure to these tick species using four collection techniques to discern host-seeking behavior. The study was carried out in 10 urban sites inhabited by capybaras in Uberlândia, a BSF-free municipality in southeastern Brazil. Ticks were collected in areas of 400 m2 at each site and at three seasons. Within the same municipality, the distance and speed of A. sculptum nymphs moving towards the CO2 traps were evaluated. In a sample of ticks Rickettsia DNA was investigated. During the study period, 52,953 ticks were collected. Among these, 83.4 % were A. sculptum (1,523 adults, 10,545 nymphs and 32,104 larvae) and 16.6 % were A. dubitatum (464 adults, 2,153 nymphs and 6,164 larvae). An average annual questing tick density of 4.4/m² was observed, with the highest density recorded at one site in autumn (31.8/m²) and the lowest in summer at another site (0.03/m²). The visual search yielded the highest proportion of A. sculptum larvae, constituting 47 % of the total and 63.6 % of all A. sculptum larvae. In contrast, CO2 traps collected a greater proportion of nymphs and adults of A. sculptum ticks. In the case of A. dubitatum, the CO2 trap was the most efficient technique with 57.7 % of captures of this species, especially of nymphs (94.5 % of captures) and adults (97.8 % of captures). Ticks' ambush height on vegetation (9 to 77 cm), observed by visual search 30 times, yielded a total of 20,771 ticks. Of these, 28 (93 %) were A. sculptum ticks, with only two (7 %) identified as A. dubitatum ticks. Among A. sculptum ticks, the nymph was the most attracted stage to humans and larva in the case of A. dubitatum. Amblyomma sculptum adults and nymphs were significantly more attracted to humans than those of A. dubitatum, but A. dubitatum larvae were significantly more attracted than the same stage of A. sculptum. The maximum distance and speed of horizontal displacement for A. sculptum nymphs were five meters and 2.0 m/h, respectively. The only species of Rickettsia detected in ticks, exclusively in A. dubitatum, was R. bellii. Importantly, it was observed that the higher the proportion of A. sculptum in the community of ticks, the lower the rate of infection of A. dubitatum by R. bellii. In conclusion, host-seeking behavior differed between the two tick species, as well as between stages of the same species. A greater restriction of A. dubitatum ticks to the soil was observed, while larvae and nymphs of A. sculptum dispersed higher in the vegetation. The behavior presented by A. sculptum provides greater opportunities for contact with the hosts, while A. dubitatum depends more on an active search for a host, the hunter behavior. Taken together, these observations show that a human being crossing an area infested with A. sculptum and A. dubitatum ticks will have almost exclusive contact with A. sculptum larvae and/or nymphs. Humans in a stationary position (sitting, lying or immobile) are exposed to both tick species, but they are more attractive to adults and mainly nymphs of A. sculptum compared to the corresponding stages of the tick A. dubitatum. The negative effect of A. sculptum on A. dubitatum infection by R. bellii deserves further studies.

Survey of Rickettsia spp. in ticks (Acari: Ixodidae) infesting opossums (Didelphis albiventris) and capybaras (Hydrochoerus hydrochaeris) from an urban park in southeastern Brazil.

Ticks are hematophagous arthropods and, during feeding, may transmit pathogens to vertebrate hosts, including humans. This study aimed to investigate the presence of Rickettsia spp. in ticks collected between 2010 and 2013 from free-ranging capybaras (Hydrochoerus hydrochaeris) and opossums (Didelphis albiventris) that inhabit Sabiá Park in Uberlândia, Brazil. Overall, 1,860 ticks were collected: 1,272 (68.4%) from capybaras (487 of the species Amblyomma sculptum, 475 adults and 12 nymphs; 778 Amblyomma dubitatum, 727 adults and 51 nymphs; and seven larva clusters of the genus Amblyomma); and 588 (31.6%) from opossums (21 A. sculptum, one adult and 20 nymphs; 79 A. dubitatum, all nymphs; 15 Ixodes loricatus, 12 adults and three nymphs; 457 Amblyomma sp. larva clusters; 15 Ixodes sp. larva clusters; and one Argasidae larva cluster). Out of 201 DNA samples tested for the presence of Rickettsia spp. DNA using polymerase chain reaction (PCR) 12 showed amplification of a gtlA gene segment that was specific to Rickettsia bellii, a bacterium non-pathogenic to humans. As there has been a report showing serological evidence of infections caused by Rickettsia species of the spotted fever group (SFG) in capybaras and opossums in the park, including Rickettsia rickettsii, the etiological agent of Brazilian spotted fever, and considering the presence of A. sculptum ticks, which are aggressive to humans, as well as these vertebrate hosts, which are amplifiers of R. rickettsii, it is important to monitor the presence of SFG rickettsiae in the Sabiá Park, which is visited daily by thousands of people.

Molecular detection of Borrelia sp. in Ornithodoros cavernicolous (Acari: Argasidae) in midwestern Brazil.

Ticks are obligate hematophagous parasites that can transmit to vertebrate hosts several pathogens, including viruses, bacteria, protozoa and helminths. Among these agents, some Borrelia species some Borrelia species cause disease in humans and other vertebrate hosts; therefore, they have medical and veterinary health importance. To gather additional information on Borrelia species in Brazil, the current study aimed to detect the presence of these species in Ornithodoros cavernicolous ticks collected in September 2019 from cement pipes that are used by bats as shelter in a farm located in the midwestern region of Brazil. DNA samples obtained from 18 specimens of O. cavernicolous were subjected of two polymerase chain reactions, targeting a segment of the Borrelia fla B gene. Of the samples tested, only one (6 %, 1/18) showed amplification. The nucleotide sequence of the amplified DNA showed more than 97 % (293/300) identity with a sequence of a Borrelia sp. detected in blood collected from a bat from Macaregua Cave, Colombia, and more than 97 % (292/300) detected in lungs from vampire bats from northeastern Brazil. The deduced amino acid sequences were identical to each other. Phylogenetic analysis indicated that these sequences formed a group of Borrelia species (putatively associated with bats) that is closely related to sequences of Borrelia species of the Lyme borreliosis group. Further investigations should be carried out in order to determine whether the sequence of the Borrelia sp. we found belongs to a new taxon. It will also be of great importance to determine which vertebrate hosts, besides bats, O. cavernicolous ticks can parasitize in order to investigate whether the Borrelia sp. we found may be transmitted and cause disease to the other vertebrate hosts.

Ticks (Acari: Ixodidae) on marsh deer (Blastocerus dichotomus) at a conservation center: infestation and Rickettsia parkeri infection dynamics along nine years.

The objective of this work was to evaluate the relationship between the populations of the ticks Amblyomma triste Koch, 1844, Rhipicephalus microplus (Canestrini, 1888), Amblyomma sculptum Berlese, 1888, the pathogenic bacteria Rickettsia parkeri and a marsh deer (Blastocerus dichotomus) population after its removal from a pristine environment. For this purpose, ticks were collected from the cervical region of deer at the Marsh Deer Conservation Center in Promissão, São Paulo State, Brazil for nine consecutive years (2000 - 2008). Deer in captivity at the Center were kept in 2,000 m² paddocks surrounded by two-meter-high fences in the Tiete-river marsh. In total, 1,012 ticks of 26 deer were collected. Prevalence of the species A. triste among tick-infested hosts was the highest in the first triennium but decreased to the second and further to the third triennium. In contrast, the R. microplus prevalence amidst infested host population, increased from the first to the third triennium and was the species that attained the highest infestation intensity. Amblyomma sculptum was the tick with the lowest infestation prevalence and intensity throughout the period. The change in the proportion between the two most prevalent species was attributed to the new environment, specifically its restricted size and within it a dry area more suitable for R. microplus. DNA of 424 ticks processed in 276 pools was tested for Rickettsia genetic material by polymerase chain reactions (PCR). Twenty samples of the study were positive for the rickettsial gltA gene. Of these, 18 were from A. triste ticks and revealed the presence of the ompA spotted fever group gene as well. Eleven samples were sequenced and showed 100% identity with R. parkeri sensu stricto. Two samples from R. microplus did not amplify ompA gene neither yielded product in a PCR specific for Rickettsia bellii. Sequencing of the gltA gene in the DNA of these two ticks was also 100% identical with R. parkeri s.s. In conclusion, the changes in the deer environment modified the tick populations but maintained, at least temporary, R. parkeri bacteria in A. triste ticks. Rhipicephalus microplus was refractory to the R. parkeri infection and bacterial DNA in this tick species indicated DNA spill over from other tick species. It was demonstrated that captive marsh deer may sustain cattle tick populations on its own. This would hardly occur under pristine conditions because of the inadequacy the marsh deer´s naturally humid habitat for the cattle tick. However, deer transportations of R. microplus ticks from one farm to another may occur whenever habitat loss pushes this wild animal towards farms.

Relapsing Fever Group Borreliae in Human-Biting Soft Ticks, Brazil.

We conducted a molecular survey for Borrelia spp. in Ornithodoros ticks previously reported as biting humans. We collected specimens in natural ecosystems and inside human dwellings in 6 states in Brazil. Phylogenetic analyses unveiled the occurrence of 4 putatively new species of relapsing fever group borreliae.

Free-living capybaras (Hydrochoerus hydrochaeris) in an urban area in Brazil: biochemical and hematological parameters

Capybaras have found favorable conditions for survival and reproduction in green urban environments. In recent years, the population of these large rodents has been increasingly abundant in several brazilian cities such as Uberlândia, a municipality of the southeastern region with a Cerrado biome. Capybaras are important in the Brazilian Spotted Fever epidemiological chain, by amplifying infection rates of the vector population. However, knowledge of this host's physiology is scarce. Thus, the aim of this work was to describe hematological and biochemical parameters of free-living capybaras groups in urbanized areas in the city of Uberlândia, Minas Gerais State, Brazil. Capybaras were captured in 4 different locations of Uberlândia city, Minas Gerais state, including 1 Condominium (P1), 1 Private Market Garden (P2), 1 Private Club (P3) and 1 Municipal Park (P4). The animals were baited into an octagonal iron corral and chemically contained with anesthetic darts. After sedated, blood was collected from the femoral vein in tubes with and without EDTA. Biochemical evaluation, hematological analysis with differential leukocyte counts and search for Dirofilaria sp. were done. The blood count and biochemistry values obtained from animals of different ages, sex and sectors (P1, P2, P3 and P4) were submitted to the Shapiro-Wilk normality test, considering 95% significance. Values that had a normal distribution were subjected to ANOVA tests followed by Student's t-test. Values that did not follow normality were submitted to the Kruskal-Wallis test, to obtain a P-value, with a significance level of 95%. A total of 19 capybaras were captured: 4 in P1, 6 in P2, 4 in P3 and 5 in P4. From the 19 animals, 13 were females (68.42%) and 6 were males (31.57%), 12 adults (63.15%) and 7 juveniles (36.84%). Apart from occasional skin scars and moderate to intense Ambyomma spp. tick infestations, all captured animals were healthy on a broad examination. From 5 animals captured in P4, despite the use of anticoagulant, blood from 4 animals clotted fast. No microfilariae were found in the thick drop test in any of the 19 animals sampled, and in 2 adult female capybaras captured in P1, Kurloff cells were observed. Hematological and biochemical values presented no major differences when comparing sex and age. Nevertheless, differences in liver and kidney profile were observed between the capybara groups, including ALT, alkaline phosphorus, BUN and creatinine. Blood from 4 animals clotted fast, despite the use of EDTA tubes. Blood clotting of samples with anticoagulant in this work could be associated with some physiological features inherent to capybaras. Many attempts were required to obtain enough blood from each individual due to the rapid hemostasis, what come in accordance with reports in literature. Kurloff cells were observed in 2 adult female capybaras captured in P1, which can be found in peripheral blood of female rodents during follicular phase of estrous cycle. Hematological and biochemical values differences in liver enzymes such as ALT and alkaline phosphorus, and kidney profile enzymes including BUN and creatinine could be associated to capture stress or dietetic variation between groups. Despite statistical relevant, the values were still in accordance with other works, although comparisons should be done with caution since various environments exert a diverse array of stimulus upon the animals such as parasitic, infective, stress, nutritional, social and undoubtedly blood parameters mirror them. In conclusion, this work contributes to the standardization of free-living capybaras' physiological parameters in urban areas.(AU)

Ticks and Rickettsia on anteaters from Southeast and Central-West Brazil.

The giant anteater (Myrmecophaga tridactyla) and the collared anteater (Tamandua tetradactyla) are widespread in Brazil and found in all Brazilian biomes. These hosts frequently use domestic animal environments such as pastures, where tick and related microorganism interchange may occur between hosts. Reports of tick infestations of these animals are scattered and refer to small samples and/or are geographically restricted. We herein present data on a wide geographic distribution of ticks and their Rickettsia collected from 72 giant and 30 collared anteaters, mostly road killed, over a period of 18 years, from Southeast and Central-West Brazil encompassing four States and 46 Municipalities. Overall nine tick species (Amblyomma auricularium, A. calcaratum, A. nodosum, A. ovale, A. parvum, A. sculptum, A. triste, Rhipicephalus microplus and R. sanguineus sensu lato) were collected from anteaters. Amblyomma sculptum, A. nodosum, and A. calcaratum were the most prevalent corresponding to, respectively, 48.8%, 39.3% and 2.7% of all ticks (n = 1775). However, A. nodosum tick numbers on collared anteaters were significantly higher (P < 0.001) than those on giant anteaters. At the same time, an abundance of A. sculptum adults on giant anteaters was significantly higher (Z = 2.875; P = 0.004) than that of A. nodosum and only eight A. sculptum nymphs were found on collared anteaters. DNA samples from 20 ticks from nine different animals yielded a visible amplicon in PCR targeting gltA. The PCR products targeting spotted-fever Rickettsia gene (ompA) from five adults of A. nodosum were sequenced and were shown to be 100% identical to Rickettsia parkeri strain NOD (MF737635.1). The product of one nymph and one adult of A. sculptum yielded a sequence 99% identical to R. parkeri strain NOD. Further, Rickettsia bellii genes were found in three A. nodosum adults. Ecological, behavioral and anatomical traits of anteaters are discussed to explain reported tick infestations and Rickettsia DNA found.

In vitro efficacy of Metarhizium anisopliae sensu lato against unfed Amblyomma parvum (Acari: Ixodidae).

Amblyomma parvum Aragão (Acari: Ixodidae) is a tick species found with wide distribution in the Neotropical region. Even though it is a wildlife-related tick, it is also a frequent parasite of domestic animals, is aggressive to human beings and may harbor pathogenic microorganisms. Therefore, it is a target species for control on domestic animals, particularly those at the rural-wildlife interface. Herein, the efficacy of two isolates (E9 and IBCB 425) of an entomopathogenic fungus, Metarhizium anisopliae sensu lato, already evaluated for ticks that parasitize domestic animals, was tested against unfed A. parvum adults. Both isolates displayed high acaricidal efficacy after immersion in fungal conidial suspensions for 5 min. Isolate E9 killed all ticks by the 7th day post-treatment, and isolate IBCB 425 did so by the 11th day. Tick mortality of 80 and 90% was achieved as early as the 3rd and 4th days, respectively, with both treatments. Thus, if a commercial M. anisopliae s.l. acaricide against domestic animal ticks is developed, it would also be effective against A. parvum.

Ticks (Acari: Ixodidae) in the Serra da Canastra National Park in Minas Gerais, Brazil: species, abundance, ecological and seasonal aspects with notes on rickettsial infection.

The Cerrado Biome is the second largest in Brazil covering roughly 2 million km2, with varying features throughout its area. The Biome is endangered but it is also source of animal species for rural, green urban and degraded rainforest areas. Ticks are among Cerrado species that establish at anthropogenic sites and although information about them is steadily increasing, several features are unknown. We herein report tick species, abundance and some ecological relationships within natural areas of the Cerrado at higher altitudes (800-1500 m) within and around Serra da Canastra National Park, in Minas Gerais State Brazil. In total of 1196 ticks were collected in the environment along 10 campaigns held in 3 years (2007-2009). Amblyomma sculptum was the most numerous species followed by Amblyomma dubitatum and Amblyomma brasiliense. Distribution of these species was very uneven and an established population of A. brasiliense in the Cerrado is reported for the first time. Other tick species (Amblyomma ovale, Amblyomma nodosum, Amblyomma parvum, Ixodes schulzei and Haemaphysalis leporispalustris) were found in lesser numbers. Domestic animals displayed tick infestations of both rural and urban origin as well as from natural areas (Rhipicephalus sanguineus sensu lato, Rhipicephalus microplus, Dermacentor nitens, A. sculptum, A. ovale, Amblyomma tigrinum, Argas miniatus). Amblyomma sculptum had the widest domestic host spectrum among all tick species. DNA of only one Rickettsia species, R. bellii, was found in an A. dubitatum tick. Several biological and ecological features of ticks of the studied areas are discussed.

Successful Infection of Tick Cell Cultures of Rhipicephalus sanguineus (Tropical Lineage) with Ehrlichia canis.

There are two distinct lineages of ticks, Rhipicephalus sanguineus, in South America: tropical and temperate lineages. Only the tropical lineage is recognized as competent vector for Ehrlichia canis. The epidemiological data of canine monocytic ehrlichiosis is congruent with the distribution of the two lineages of R. sanguineus. Herein, we report the infection of R. sanguineus (tropical lineage) cell cultures with E. canis, after cryopreservation. R. sanguineus (tropical lineage) cell identity was confirmed by sequencing using a 16S rDNA gene fragment. Tick cell cultures were prepared in L-15B medium supplemented with 10%, 15%, and 20% Fetal Bovine Serum (FBS), and 10% of Tryptose Phosphate Broth (TPB). Cell cultures developed better at the concentration of 20% of FBS. Cultures in the fifth harvest (approximately 7 months later) were selected for the first infections. Optimal R. sanguineus cell growth and adhesion was observed (5.0 × 106 cells/mL, and the population doubling time every 57 h). Once infected with E. canis, the cultures were maintained in L-15B medium supplemented with 2% and 5% of FBS fortified with iron and 10% TPB. Infected cells were also cryopreserved. DNA was extracted from infected and noninfected cells and analyzed using quantitative real-time PCR targeting the E. canis-dsb gene. Primary culture of the fifth passage was infected by E. canis and it maintained the pathogen for at least 40 days before partial cell destruction. Subcultures of infected cells (fresh and cryopreserved cultures) onto new tick cell cultures were successful. The E. canis infection was confirmed by real-time PCR and light and transmission electron microscopy. The R. sanguineus (tropical lineage) cells infected with E. canis successfully infected new tick cell cultures, showing that these cells could be an alternative substrate for maintenance of this pathogen.

Influence of microhabitat use and behavior of Amblyomma sculptum and Amblyomma dubitatum nymphs (Acari: Ixodidae) on human risk for tick exposure, with notes on Rickettsia infection.

Brazilian spotted fever (BSF) is a potentially lethal human disease caused by Rickettsia rickettsii transmitted by ticks, including Amblyomma sculptum. However, in Southeast Brazil, where most BSF cases occur, capybaras are key hosts for both A. sculptum and Amblyomma dubitatum. We therefore compared the risk of human exposure to these ticks at a non-endemic anthropogenic site in Southeast Brazil where both tick species are maintained by capybaras and occur at high abundance. Cloth dragging, human baits and CO2 traps were used to assess tick abundance and risk for human exposure. The two tick species displayed profound differences in behavior and microhabitat use. Notably, A. sculptum but not A. dubitatum quested for hosts openly from vegetation (ambush behavior) and infested human baits. Furthermore, A. dubitatum was more aggregated at a specific site whereas A. sculptum was more widespread along differing and drier microhabitats. Adults and nymphs of both species were infected with Rickettsia bellii. Overall, the results indicate that even though both species co-existed in the same area, A. sculptum posed a greater risk for biting humans and thus also for transmitting tick-borne pathogens.

Successful infection of tick cell cultures of Rhipicephalus sanguineus (Tropical Lineage) with Ehrlichia canis

There are two distinct lineages of ticks, Rhipicephalus sanguineus, in South America: tropical and temperate lineages. Only the tropical lineage is recognized as competent vector for Ehrlichia canis. The epidemiological data of canine monocytic ehrlichiosis is congruent with the distribution of the two lineages of R. sanguineus. Herein, we report the infection of R. sanguineus (tropical lineage) cell cultures with E. canis, after cryopreservation. R. sanguineus (tropical lineage) cell identity was confirmed by sequencing using a 16S rDNA gene fragment. Tick cell cultures were prepared in L-15B medium supplemented with 10%, 15%, and 20% Fetal Bovine Serum (FBS), and 10% of Tryptose Phosphate Broth (TPB). Cell cultures developed better at the concentration of 20% of FBS. Cultures in the fifth harvest (approximately 7 months later) were selected for the first infections. Optimal R. sanguineus cell growth and adhesion was observed (5.0?×?106 cells/mL, and the population doubling time every 57?h). Once infected with E. canis, the cultures were maintained in L-15B medium supplemented with 2% and 5% of FBS fortified with iron and 10% TPB. Infected cells were also cryopreserved. DNA was extracted from infected and noninfected cells and analyzed using quantitative real-time PCR targeting the E. canis-dsb gene. Primary culture of the fifth passage was infected by E. canis and it maintained the pathogen for at least 40 days before partial cell destruction. Subcultures of infected cells (fresh and cryopreserved cultures) onto new tick cell cultures were successful. The E. canis infection was confirmed by real-time PCR and light and transmission electron microscopy. The R. sanguineus (tropical lineage) cells infected with E. canis successfully infected new tick cell cultures, showing that these cells could be an alternative substrate for maintenance of this pathogen.

Successful Infection of Tick Cell Cultures of Rhipicephalus sanguineus (Tropical Lineage) with Ehrlichia canis

There are two distinct lineages of ticks, Rhipicephalus sanguineus, in South America: tropical and temperate lineages. Only the tropical lineage is recognized as competent vector for Ehrlichia canis. The epidemiological data of canine monocytic ehrlichiosis is congruent with the distribution of the two lineages of R. sanguineus. Herein, we report the infection of R. sanguineus (tropical lineage) cell cultures with E. canis, after cryopreservation. R. sanguineus (tropical lineage) cell identity was confirmed by sequencing using a 16S rDNA gene fragment. Tick cell cultures were prepared in L-15B medium supplemented with 10%, 15%, and 20% Fetal Bovine Serum (FBS), and 10% of Tryptose Phosphate Broth (TPB). Cell cultures developed better at the concentration of 20% of FBS. Cultures in the fifth harvest (approximately 7 months later) were selected for the first infections. Optimal R. sanguineus cell growth and adhesion was observed (5.0?×?106 cells/mL, and the population doubling time every 57?h). Once infected with E. canis, the cultures were maintained in L-15B medium supplemented with 2% and 5% of FBS fortified with iron and 10% TPB. Infected cells were also cryopreserved. DNA was extracted from infected and noninfected cells and analyzed using quantitative real-time PCR targeting the E. canis-dsb gene. Primary culture of the fifth passage was infected by E. canis and it maintained the pathogen for at least 40 days before partial cell destruction. Subcultures of infected cells (fresh and cryopreserved cultures) onto new tick cell cultures were successful. The E. canis infection was confirmed by real-time PCR and light and transmission electron microscopy. The R. sanguineus (tropical lineage) cells infected with E. canis successfully infected new tick cell cultures, showing that these cells could be an alternative substrate for maintenance of this pathogen.

Amblyomma sculptum (Amblyomma cajennense complex) tick population maintained solely by domestic pigs.

In Brazil Amblyomma sculptum from Amblyomma cajennense complex is a tick species with a rather broad distribution encompassing the Cerrado Biome and devastated areas of the Atlantic rainforest. This species is also the major vector to humans of Rickettsia rickettsii, agent of the Brazilian spotted fever. Main primary hosts for the adult stage and frequently associated to high environmental infestation levels are the native capybaras and tapirs and a domestic host, the horse. Recent, however, solely circumstantial evidence, has shown that pigs (Sus scrofa) domestic, feral or exotic (wild boars) as well as wild suidae may maintain A. sculptum populations as well. We herein describe the maintenance of an A. sculptum tick population by domestic pigs for three years when raised in paddocks. Observations herein described occurred in the facilities of an intensive outdoor pig production system within a farm in Uberaba municipality southeast Brazil. Initial evaluation was done upon request due to human tick-bite complains in June 2013. Later tick infestations were evaluated at each of eight consecutive seasons from August 2014 to May 2016. In the first evaluation, 104 nymphs and one female A. sculptum were collected from four pigs and 269 nymphs of A. sculptum and 12 Amblyomma spp larva clusters from the paddocks. Only one A. sculptum nymph was found in each of the surrounding bovine pasture and a nearby riparian forest. Seven Rhipicephalus spp and three Amblyomma spp larva were found in the former as well. Infestations were greatly reduced with elimination of the two most infested paddocks and mowing of vegetation. Still along the inspection of eight consecutive seasons A sculptum ticks were collected overwhelmingly adults from pigs. Thus, observations herein described show that outdoor pig raising may provide both a permissive environment and adequate host allowing for a minimal threshold for the maintenance of A. sculptum populations. Since raising domestic pigs in paddocks to increase animal welfare is an increasing practice, it may indicate a new trend in this parasitism, with yet an unknown effect upon animal and human health.

Microorganisms contaminating ticks collected at natural reserves or wild animals / Microrganismos contaminantes de carrapatos coletados em reservas naturais ou animais selvagens

This work investigated microorganisms responsible for the contamination and death of ticks from natural reserves and wild animals and later kept in the Laboratory of Ixodology in the Veterinary School of the Federal University of Uberlândia. Such investigation aimed prevention of tick death in the laboratory but also search for microorganisms to be used in the biological control of ticks. From four tick samples of Amblyomma genus, the following agents were isolated: Staphylococus sp, Gram positive bacillus, filamentous fungi of the genera Aspergillus and Penicillium, and a yeast identified as Non-albicans Candida and Cryptococcus sp. Even though the source of contamination of these ticks is uncertain, this study displayed the necessity of to better evaluating the spread of pathogens by ticks, as well as those known to be transmitted solely during tick feeding.

Neste trabalho foram investigados microrganismos responsáveis pela colonização e morte de carrapatos provenientes de reservas naturais ou animais selvagens e mantidos posteriormente no Laboratório de Ixodologia da Faculdade de Medicina Veterinária da Universidade Federal de Uberlândia. Esta investigação se fez necessária para tentar prevenir mortalidade de carrapatos no laboratório, mas também para contribuir com a busca por microrganismos que poderiam ser utilizados no controle biológico do ácaro. Foram isolados de cinco amostras de carrapatos do gênero Amblyomma os seguintes microrganismos: Staphylococus sp, bacilos Gram positivos, fungos filamentosos dos gêneros Aspergillus e Penicillium, além de leveduras identificadas como Candida não-albicans e Cryptococcus sp. Mesmo que a origem da contaminação dos carrapatos com estes microrganismos seja incerta este trabalho indica a necessidade de se avaliar melhor a difusão de outros patógenos por carrapatos, além daqueles transmitidos com a hematofagia.

The sialotranscriptome of Amblyomma triste, Amblyomma parvum and Amblyomma cajennense ticks, uncovered by 454-based RNA-seq.

BACKGROUND: Tick salivary constituents antagonize inflammatory, immune and hemostatic host responses, favoring tick blood feeding and the establishment of tick-borne pathogens in hosts during hematophagy. Amblyomma triste, A. cajennense and A. parvum ticks are very important in veterinary and human health because they are vectors of the etiological agents for several diseases. Insights into the tick salivary components involved in blood feeding are essential to understanding vector-pathogen-host interactions, and transcriptional profiling of salivary glands is a powerful tool to do so. Here, we functionally annotated the sialotranscriptomes of these three Amblyomma species, which allowed comparisons between these and other hematophagous arthropod species. METHODS: mRNA from the salivary glands of A. triste, A. cajennense and A. parvum ticks fed on different host species were pyrosequenced on a 454-Roche platform to generate four A. triste (nymphs fed on guinea pigs and females fed on dogs) libraries, one A. cajennense (females fed on rabbits) library and one was A. parvum (females fed on dogs) library. Bioinformatic analyses used in-house programs with a customized pipeline employing standard assembly and alignment algorithms, protein databases and protein servers. RESULTS: Each library yielded an average of 100,000 reads, which were assembled to obtain contigs of coding sequences (CDSs). The sialotranscriptome analyses of A. triste, A. cajennense and A. parvum ticks produced 11,240, 4,604 and 3,796 CDSs, respectively. These CDSs were classified into over 100 distinct protein families with a wide range of putative functions involved in physiological and blood feeding processes and were catalogued in annotated, hyperlinked spreadsheets. We highlighted the putative transcripts encoding saliva components with critical roles during parasitism, such as anticoagulants, immunosuppressants and anti-inflammatory molecules. The salivary content underwent changes in the abundance and repertoire of many transcripts, which depended on the tick and host species. CONCLUSIONS: The annotated sialotranscriptomes described herein richly expand the biological knowledge of these three Amblyomma species. These comprehensive databases will be useful for the characterization of salivary proteins and can be applied to control ticks and tick-borne diseases.

Comparing feeding and reproductive parameters of Amblyomma parvum tick populations (Acari: Ixodidae) from Brazil and Argentina on various host species.

Amblyomma parvum is a Neotropical tick that is widely spread and a potential vector of pathogens, including Rickettsiae. Genetic differences are remarkable between A. parvum populations from Brazil and Argentina. In this work, feeding and reproduction parameters of A. parvum ticks from these two populations were compared on some key host species to evaluate possible differences in host suitability between them. On the whole parameters of these tick populations were similar when fed on the same host and varied similarly on different host species. Still, bovines were more suitable host for Argentinian larvae than for Brazilian cohorts. It was observed that guinea pigs were the best host A. parvum immatures from both origins, as depicted from higher recovery rate of larvae and heavier engorged nymph weights. Canids and bovids were host species most suitable to adults of both tick populations as shown by the highest number of larvae produced by adult females that engorged on these hosts. Taken together, results showed that in spite of the genetic divergence, A. parvum from Argentina and Brazil have similar biological performance on various host species.

Ticks on birds in a savanna (Cerrado) reserve on the outskirts of Uberlândia, Minas Gerais, Brazil.

We report tick infestations on birds, in the environment and on domestic animals in a non-forested phytophysiognomy, the savanna-like Cerrado sensu stricto, in a natural reserve on the outskirts of the urban area of Uberlândia, Minas Gerais, Brazil. Overall, 238 birds within 50 species, 15 families and six orders were caught. Passeriformes were the most numerous, with 216 birds (90.75%), among which 22 had ticks (n = 31). Within this order, the prevalence of tick infestation was 10.2%, and the abundance and mean intensity were 0.14 and 1.41, respectively. Only immature ticks of the species Amblyomma nodosum were found on the birds. The tick species found both on animals (Rhipicephalus sanguineus, Rhipicephalus (Boophilus) microplus, Amblyomma cajennense and Dermacentor nitens) and in the environment (Amblyomma dubitatum, Rhipicephalus (B.) microplus and Amblyomma cajennense) were as expected. This difference in tick species between the environment and birds possibly occurred because the sampling of the environment was limited to the ground. This study also highlights the importance of the diverse microenvironments used by ticks and hosts in the same area and the complex ecology of bird-tick relationships. Ecological and epidemiological aspects of the findings are discussed.

Ticks on birds in a savanna (Cerrado) reserve on the outskirts of Uberlândia, Minas Gerais, Brazil / Carrapatos em aves de uma reserva do Cerrado na periferia de Uberlândia, Minas Gerais, Brasil

We report tick infestations on birds, in the environment and on domestic animals in a non-forested phytophysiognomy, the savanna-like Cerrado sensu stricto, in a natural reserve on the outskirts of the urban area of Uberlândia, Minas Gerais, Brazil. Overall, 238 birds within 50 species, 15 families and six orders were caught. Passeriformes were the most numerous, with 216 birds (90.75%), among which 22 had ticks (n = 31). Within this order, the prevalence of tick infestation was 10.2%, and the abundance and mean intensity were 0.14 and 1.41, respectively. Only immature ticks of the species Amblyomma nodosum were found on the birds. The tick species found both on animals (Rhipicephalus sanguineus, Rhipicephalus (Boophilus) microplus, Amblyomma cajennense and Dermacentor nitens) and in the environment (Amblyomma dubitatum, Rhipicephalus (B.) microplus and Amblyomma cajennense) were as expected. This difference in tick species between the environment and birds possibly occurred because the sampling of the environment was limited to the ground. This study also highlights the importance of the diverse microenvironments used by ticks and hosts in the same area and the complex ecology of bird-tick relationships. Ecological and epidemiological aspects of the findings are discussed.

Nesse trabalho relatam-se infestações de carrapatos em aves, meio ambiente e em animais domésticos em uma fitofisionomia não florestal, o Cerrado stricto sensu, de uma reserva natural na periferia da área urbana de Uberlândia, Minas Gerais, Brasil. Para tal, 238 aves de 50 espécies foram capturadas, pertencentes a 15 famílias e seis ordens. Passeriforme foi a mais numerosa, com 216 indivíduos (90,75%), dos quais 22 estavam parasitados com 31 carrapatos. Nos Passeriformes a prevalência de infestação de carrapatos foi de 10,2%, a abundância e intensidade média foi de 0,14 e 1,41, respectivamente. Apenas carrapatos imaturos da espécie Amblyomma nodosum foram encontrados em aves. As espécies de carrapatos encontradas tanto em animais (Rhipicephalus sanguineus, Rhipicephalus (Boophilus) microplus, Amblyomma cajennense, Dermacentor nitens) como no ambiente (Amblyomma dubitatum, Rhipicephalus (B.) microplus, Amblyomma cajennense) foram aquelas já esperadas. Esta diferença de espécies de carrapatos entre ambiente e de aves possivelmente ocorreu porque a amostragem do ambiente se restringiu ao solo. Esse estudo também destaca a importância dos diversos microambientes usados por carrapatos e hospedeiros em uma mesma área e a complexa ecologia das relações ave-carrapato. Aspectos ecológicos e epidemiológicos dos achados são discutidos.