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.

Ticks biting humans in the Brazilian savannah: Attachment sites and exposure risk in relation to species, life stage and season.

Information about human tick bites in Brazil is mostly anecdotal. Published information is typically restricted to single tick infestation episodes and does not address human exposure occurring on a daily basis in natural, rural, or green urban areas. We present a comprehensive 2-yr study on human parasitism during a broad survey on ticks within a Brazilian savannah reserve. Overall, 439 tick bites were recorded from the following species: Amblyomma sculptum (n = 331 bites), Amblyomma parvum (n = 64), Amblyomma auricularium (n = 3), Rhipicephalus microplus (n = 2), Dermacentor nitens (n = 1) and 38 Amblyomma spp. ticks. Nymphs accounted for most tick bites (n = 292, 66.5 % of all bites) and these were overwhelmingly A. sculptum (92.8 % of nymphal bites). The main adult tick biting humans was A. parvum (n = 61, 50 % of all adult tick bites) followed closely by A. sculptum (n = 58, 47.5 % of all adult tick bites). Winter was the season with the highest percentage of tick bites (39.7 % of all bites), followed by spring (32.4 %); summer (18.9 %) and autumn (9 %). Amblyomma sculptum adult bites peaked in summer whereas nymphal bites occurred primarily in winter and spring. Amblyomma parvum adult bites peaked in spring and summer. The most common tick attachment sites included the waist, legs and belly, but A. parvum adults were recorded from the head of humans as well. A noteworthy observation was the lack of human parasitism by Amblyomma triste, the third most prevalent species in the environment. This tick species is a frequent human biter in both Uruguay and Argentina where it transmits a pathogen, Rickettsia parkeri, to humans.

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.

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.

Ambush behavior of the tick Amblyomma sculptum (Amblyomma cajennense complex) (Acari: Ixodidae) in the Brazilian Pantanal.

We herein describe the ambush behavior of Amblyomma sculptum (Berlese 1888), a widespread and epidemiologically important tick in Brazil. Along two years of sampling by visual search in the Brazilian Pantanal, A. sculptum ticks were observed on the vegetation and in the leaf litter. Most of the ticks were observed between 10 and 50cm above ground level and less than five percent of the total were positioned below 10cm, indicating that they are seeking for middle or large-sized hosts. In both seasons, vapor saturation deficit was low during the morning. No significant relationship was found between questing ticks and daytime interval of observation or saturation deficit. However, questing tick numbers seem be higher in the end of the morning, when saturation deficit reaches its peak. Behavioral patterns of A. sculptum ticks observed in Pantanal underscore the occurrence of this tick and human contact at green anthropogenic sites. Considering A. sculptum questing behavior, inferences on human behavioral patterns that enhance or avoid contact with ticks are discussed.

Efficacy of Tagetes minuta (Asteraceae) essential oil against Rhipicephalus sanguineus (Acari: Ixodidae) on infested dogs and in vitro.

Ticks from Rhipicephalus sanguineus complex are widely distributed in the world and one species from this complex is the most common tick on dogs in Brazil, notably in urban areas. This tick is a vector of several diseases. Among others it transmits the agent of canine Ehrlichiosis, a major dog infectious disease and the agent of Rocky Mountain spotted fever. This tick can spread rapidly and develop intolerable infestations within no time. Currently tick control is done with acaricides and demand for such drugs has grown fast. However, R. sanguineus has already developed resistance to the main active compounds and the development of new acaricides is necessary. Many essential oils of plants have acaricidal effect and may be an important source of molecules for the synthesis of new acaricide products. In this study, we evaluated the effectiveness of a new herbal phytotherapic, consisting of the essential oil of Tagetes minuta L., against R. sanguineus in vitro and on dogs undergoing experimental infestations. The product displayed 100% efficacy against larvae, nymphs and adults of the tick on all tested conditions.

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.

Occurrence of antibodies against Neospora caninum in wild pigs (Sus scrofa) in the Pantanal, Mato Grosso do Sul, Brazil / Ocorrência de anticorpos contra Neospora caninum em porcos-monteiro (Sus scrofa) do Pantanal, Mato Grosso do Sul, Brasil

Serum samples from 83 free living wild pigs (Sus scrofa) from the Nhecolândia region, Pantanal do Mato Grosso, Brazil, were examined for the presence of antibodies against Neospora caninum by means of the indirect fluorescence antibody test (IFAT) with a cut off of 50. Antibodies were present in 10.8%, with titers of: 1:200 in one animal, 1:400 in four and 1:800 in four. Analysis using the χ2 test showed an association between sex and presence of antibodies, with females showing occurrence of 20.5% and males 2.3% (p = 0.017). No association was found between age and occurrences of antibodies against this parasite. This was the first observation of N. caninum antibodies in Brazilian wild pigs from Pantanal...

Amostras de soro de 83 porcos-monteiro (Sus scrofa) selvagens, oriundos da região de Nhecolândia, Pantanal do Mato Grosso, Brasil, foram examinadas para a presença de anticorpos contra Neospora caninum pela reação de imunofluorescência indireta (RIFI) com ponto de corte de 50. A ocorrência de anticorpos foi de 10,8%, com um animal apresentando título de 1:200, quatro com 1:400 e quatro com 1:800. Quando analisados pelo teste do X2, foi observada a existência de associação entre sexo e presença de anticorpos, com as fêmeas apresentando ocorrência de 20,5% e os machos 2,3% (p = 0,017). Não houve associação entre idade e ocorrência de anticorpos contra este parasito. Esta é a primeira observação de porcos-monteiro da região do Pantanal, apresentando anticorpos contra N. caninum...

Complementary data on four methods for sampling free-living ticks in the Brazilian Pantanal.

In this study, four methods for sampling free-living ticks that are used in ecological and human tick-bite risk studies were evaluated. Cloth dragging, carbon dioxide traps and visual searches and inspection of plant litter on the ground were used in field and forest areas within the Brazilian Pantanal. Among the three tick species collected, Amblyomma sculptum predominated, followed by Amblyomma parvum and Amblyomma ovale. Dragging, a cheap and simple technique, yielded the highest numbers of ticks, particularly nymphs. The visual search detected a high number of adult ticks and provided information on tick questing height. Even though laborious, plant litter examination showed that large numbers of ticks may use this stratum. Carbon dioxide (CO2) traps are expensive and difficult to handle, but they are highly efficient for adult ticks, especially A. parvum. These data indicate that one method alone is incapable of providing a representative sample of the tick fauna in a particular area and that multiple techniques should be used for tick population studies.

Complementary data on four methods for sampling free-living ticks in the Brazilian Pantanal / Dados complementares de quatro métodos para amostragem de carrapatos em vida livre no Pantanal brasileiro

In this study, four methods for sampling free-living ticks that are used in ecological and human tick-bite risk studies were evaluated. Cloth dragging, carbon dioxide traps and visual searches and inspection of plant litter on the ground were used in field and forest areas within the Brazilian Pantanal. Among the three tick species collected, Amblyomma sculptum predominated, followed by Amblyomma parvum and Amblyomma ovale. Dragging, a cheap and simple technique, yielded the highest numbers of ticks, particularly nymphs. The visual search detected a high number of adult ticks and provided information on tick questing height. Even though laborious, plant litter examination showed that large numbers of ticks may use this stratum. Carbon dioxide (CO2) traps are expensive and difficult to handle, but they are highly efficient for adult ticks, especially A. parvum. These data indicate that one method alone is incapable of providing a representative sample of the tick fauna in a particular area and that multiple techniques should be used for tick population studies.

Neste estudo, foram avaliados quatro métodos de amostragem de carrapatos em vida livre, usados em estudos ecológicos e avaliação do risco de picadas em humanos. Arraste de flanela, armadilhas de gás carbônico (CO2), busca visual e inspeção de serrapilheira foram aplicados em áreas campestres e florestais no Pantanal brasileiro. Dentre três espécies coletadas, a predominância foi de Amblyomma sculptum, seguida por Amblyomma parvum e Amblyomma ovale. O arraste, técnica simples e de baixo custo, resultou em maior número de carrapatos, particularmente de ninfas. A busca visual detectou alto número de carrapatos adultos e forneceu informações sobre altura de espera por hospedeiros. Apesar de trabalhoso, o exame da serrapilheira demonstrou que grande número de carrapatos pode utilizar esse estrato. Armadilhas de CO2 têm custo elevado e são difíceis de manusear, entretanto, são altamente eficientes para carrapatos adultos, em especial para A. parvum. Esses dados indicam que somente um método é incapaz de fornecer amostra representativa da ixodofauna em uma área particular e que, para estudos populacionais, técnicas múltiplas devem ser usadas.

Feral pigs as hosts for Amblyomma sculptum (Acari: Ixodidae) populations in the Pantanal, Mato Grosso do Sul, Brazil.

The Pantanal in Brazil is the largest floodplain of the world. This ecosystem, rich in wildlife, has a large feral pig population. Such a large host biomass must have a strong influence on the parasite fauna. In this work, we evaluated the role of feral pigs in the maintenance of Amblyomma sculptum (formerly Amblyomma cajennense), the most prevalent tick species in the Pantanal. Tick infestations were evaluated on 243 feral pigs and their environment. The suitability of domestic pigs, representing their feral relatives, to A. sculptum adults and nymphs was assessed experimentally. Tick infestation of feral pigs was strongly associated with that of the environment: 96 and 97 % of the ticks, respectively, were A. sculptum. The infestation prevalence on this host species was close to 90 % in the dry season and 100 % in the wet season and mean infestation intensity was above 30 ticks in both seasons. Suitability of pigs as hosts for A. sculptum was shown by the high proportion of nymphs and female ticks found engorging on captured feral pigs and adequate biological parameters displayed by ticks from experimental infestations of domestic pigs. Other tick species on feral pigs, albeit in much lower numbers, were Amblyomma parvum and Ornithodorus rostratus. Results show that feral pigs feed a high proportion of the A. sculptum adults and nymphs in their territories and should be a target for tick-borne diseases studies. This is particularly relevant to public health because all the main tick species found on feral pigs are aggressive to humans as well.

Ocorrência de anticorpos anti-leptospira spp. em diferentes sistemas de criação de suínos / Occurrence of leptospira spp. antibodies in pigs from different housing systems

A leptospirose é uma zoonose de grande importância sócio-econômica para a suinocultura. Neste estudo, objetivou-se determinar a ocorrência de anticorpos anti-Leptospira em 132 amostras de soro sangüíneo de suínos procedentes de três diferentes sistemas de produção: granja não tecnificada, granja tecnificada e granja que utiliza o sistema intensivo de suínos criados ao ar livre (SISCAL). As amostras foram processadas através da técnica de Soroaglutinação Microscópica (SAM) em campo escuro, utilizando os seguintes sorovares: Bratislava, Canicola, Grippotyphosa, Hardjo, Icterohaemorrhagiae e Wolffi. A ocorrência de anticorpos anti-Leptospira nas três granjas foi de 47,1%, sendo que identificou-se 20%, 56% e 44,4% nas granjas não tecnificada, tecnificada e o SISCAL, respectivamente. Sessenta e duas amostras foram positivas para um ou mais sorovar, sendo mais freqüentes o Icterohaemorrhagiae, Hardjo e Wolffi com ocorrência de 67,1%, 55,7% e 24%, respectivamente.

Leptospirosis is a zoonosis and an important social-economic aspect to the pig farming. In this study, aiming at the objective to determinate the occurrence of antibodies anti-Leptospira from 132 swine serum sample preceded from three differents housing systems: intensive swine farm (high technology), intensive swine farm (low technology) and free range conditions. The samples were processed through the Microscopic Aglutination Test (MAT) in dark field, using differents serovars: Bratislava, Canicola, Grippotyphosa, Hardjo, Icterohaemorrhagiae and Wolffi. The occurrence of antibodies anti-Leptospira from three differents housing systems was 47,1%, being identified 20%, 56% e 44,4% in the intensive swine farm (high technology), intensive swine farm (low technology) and free range conditions, respectively. Sixty-two serum samples were positive for one or more serovar, being more frequent Icterohaemorrhagiae, Hardjo and Wolffi, with occurrence of 67,1%, 55,7% e 24%, respectively.