Ticks (Acari: Ixodidae) and rickettsiae associated with wild boars in a rural area of Minas Gerais, Brazil.

Wild boars or feral pigs are classified by the Brazilian Institute for the Environment and Renewable Resources (IBAMA) in "Category I of invasive exotic species". They cause economic losses, harm the environment, serve as hosts and reservoirs for several zoonotic disease agents, and provide a blood meal for tick species that act as vectors for zoonotic diseases. The objective of this study was to identify tick species on wild boars, assess host-seeking ticks in the related environment, and identify other potential tick hosts coexisting with wild boars on a farm located in the state of Minas Gerais, southeastern Brazil. Additionally, the study aimed to determine the presence of rickettsiae in these arthropods and assess the exposure of wild boars to rickettsiae species from the Spotted Fever Group and Rickettsia bellii through serology. A total of 3585 host-seeking ticks from three species (Amblyomma sculptum - 41.58%; Amblyomma dubitatum - 0.39% and Rhipicephalus microplus - 0.05%) were collected in the environment and A. sculptum was the most abundant species. Thirty-one wild boars were evaluated, resulting in the collection of 415 ticks, all of which were A. sculptum. Rickettsia DNA was not detected in samples of A. sculptum and R. microplus from the environment or in A. sculptum ticks from wild boars. However, all A. dubitatum ticks (n = 14) had Rickettsia bellii DNA confirmed by the species-specific PCR protocol. Out of the 31 serum samples from wild boars, 24 reacted with at least one Rickettsia antigen. Among these, seven individuals exhibited a reaction to a probable homologous antigen (PHA) of three rickettsiae species: R. rickettsii (n = 3), R. amblyommatis (n = 3) and R. rhipicephali (n = 1). Despite the high prevalence of seroreactivity, titers were low, indicating limited exposure to Rickettsia spp. Camera traps generated 874 animal records, capturing a total of 1688 individuals. At least 11 species of birds and 14 species of mammals (12 wild and two domestic) shared the environment with wild boars and potentially shared ticks with them. These findings provide baseline information for understanding the sharing of ticks and tick-borne pathogens between wild boars and other animals within the Cerrado biome. Further studies are necessary to monitor the potential and actual risk of wild boars to harbor infected ticks and their role in the transmission and maintenance cycle of Rickettsia spp.

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.

Solid epithelioid peritoneal mesothelioma with pulmonary metastasis in feline.

Mesothelioma is a rare malignant neoplasm that affects the mesothelial cells lining the thoracic and abdominal cavities, such as the pleura, peritoneum, and pericardium. It is most prevalent in dogs and cattle, but the causes of this disease in animals are uncertain. In felines, it mainly affects the pleura, with an unfavorable prognosis. This paper explores a rare case of metastatic peritoneal mesothelioma in a 2-year-old female mixed breed cat, emphasizing its uniqueness due to the feline's age. The patient, previously treated at a private clinic, presented moderate abdominal distension as the only clinical sign. Abdominal ultrasound and peritoneal fluid cytology led to the provisional diagnosis of mesothelioma/carcinomatosis. One day after exploratory laparotomy, the animal died and was subsequently sent for necropsy. During macroscopic analysis, nodules were observed in the peritoneum, diaphragm, omentum, stomach serosa, and large intestine, and the diagnosis of solid epithelioid peritoneal mesothelioma with lung metastasis was confirmed after microscopic analysis. The diagnosis of mesothelioma is challenging, and the importance of immunohistochemical panels with specific markers such as cytokeratin AE1/AE3 and calretinin is highlighted. Considering that mesothelioma is a pathology with a poor prognosis, it is essential to include this disease in the list of differential diagnoses within veterinary oncology.

O mesotelioma é uma neoplasia maligna rara que afeta as células mesoteliais que revestem as cavidades torácica e abdominal, como a pleura, o peritônio e o pericárdio. É mais prevalente em cães e bovinos, mas as causas desta doença em animais são incertas. Nos felinos acomete principalmente a pleura, com prognóstico desfavorável. Este artigo explora um caso raro de mesotelioma peritoneal metastático em uma gata sem raça definida de 2 anos de idade, enfatizando sua singularidade devido à idade do felino. O paciente, previamente atendido em clínica particular, apresentava distensão abdominal moderado como único sinal clínico. A ultrassonografia abdominal e a citologia do líquido peritoneal levaram ao diagnóstico provisório de mesotelioma/carcinomatose. Um dia após a laparotomia exploratória, o animal veio a óbito e posteriormente encaminhado para necropsia. Durante a análise macroscópica, foram observados nódulos no peritônio, diafragma, omento, serosa estomacal e intestino grosso e o diagnóstico de mesotelioma peritoneal epitelioide sólido com metástase pulmonar foi confirmado após análise microscópica. O diagnóstico do mesotelioma é desafiador, sendo destacada a importância de painéis imunohistoquímicos com marcadores específicos como citoqueratina AE1/AE3 e calretinina. Considerando que o mesotelioma é uma patologia de prognóstico ruim, é fundamental incluir esta doença na lista de diagnósticos diferenciais dentro da oncologia veterinária.

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.

Rickettsia communities and their relationship with tick species within and around the national park of Iguaçu, Brazil.

We report Rickettsia species from 2,334 ticks collected from environment (1,939 ticks) and animals (395 ticks) in the largest inland fragment of the Atlantic rainforest of southern Brazil and its fragments. Additionally, the DNA infection rates of Amblyomma ovale tick populations in the Neotropics with Rickettsia bellii and Rickettsia parkeri strain Atlantic rainforest were calculated using data from scientific publications, and their correlation was evaluated. From 11 tick species Rickettsia DNA was detected in seven (Amblyomma brasiliense, Amblyomma coelebs, Amblyomma incisum, Amblyomma longirostre, A. ovale, Haemaphysalis juxtakochi, Ixodes fuscipes) and was not detected in four species (Amblyomma dubitatum, Ixodes loricatus, Rhipicephalus microplus and Rhipicephalus sanguineus sensu lato). DNA of five Rickettsia species was detected (R. bellii, Rickettsia amblyommatis, Rickettsia rhipicephali, Rickettsia felis and Rickettsia sp. Aragaoi). To determine the prevalence of Rickettsia DNA positivity according to vector species, ticks were processed individually or in pools of 2-10 individuals (samples). The most prevalent Rickettsia species was R. bellii, found in 112 samples, followed by R. amblyommatis, R. rhipicephali, R. felis and Rickettsia sp. Aragaoi, found in 16, five, two and one sample, respectively. Rickettsia bellii DNA was found in five tick species with the highest infection rate in A. ovale and A. brasiliense. Absence of R. parkeri strain Atlantic rainforest in A. ovale ticks was an unexpected result. Furthermore, a negative correlation was identified between the infection rates (DNA) of R. bellii and/or R. parkeri strain Atlantic rainforest within A. ovale tick populations in the Neotropics. Putting together current knowledge, it can be proposed that, within natural settings, the diversity of rickettsiae and ticks creates a buffering effect on the overgrowth of rickettsiae and episodes of bacteremia in the hosts.

Use of selected samples to diagnose a tricky feline viral disease in a cat with uveitis and neurological signs.

This case involved a 2-year-old neutered male domestic mixed-breed cat that was rescued from the street eight months earlier. The animal presented with weakness, hyporexia, progressive weight loss, fatigue, uveitis, pale mucous membranes, dehydration (7%), and pelvic limb paresis. Aqueous humor was collected for molecular analysis for the differential diagnosis of potential etiological agents [Feline coronavirus (FCoV), Feline leukemia virus (FeLV), Feline immunodeficiency virus (FIV), Toxoplasma gondii, Cryptococcus spp., Felid herpesvirus-1 (FHV-1) and Bartonella spp.] of feline uveitis. The sample was positive by real-time reverse transcription-polymerase chain reaction (RT-qPCR) for FCoV and RT-qPCR and real-time polymerase chain reaction (qPCR) for FeLV and qPCR FIV. The cat was euthanized due to poor clinical outcomes and prognosis. A cerebrospinal fluid (CSF) sample was collected and tested, and the same pathogens were found in the aqueous humor. Small-cell follicular multicenter lymphoma and multifocal pyogranulomatous meningoencephalitis were observed upon histopathological analysis. In this study, aqueous humor and cerebrospinal fluid samples were efficient for the detection of coinfection with FIV, FeLV, and FCoV.

O caso refere-se a um gato de dois anos de idade, sem raça definida, resgatado da rua há oito meses. O animal apresentava fraqueza, hiporexia, emagrecimento progressivo, cansaço fácil, uveíte, mucosas pálidas, desidratação (7%) e paresia de membros pélvicos. O humor aquoso foi coletado para o diagnóstico molecular diferencial de potenciais agentes etiológicos [coronavírus felino (FCoV), vírus da leucemia felina (FeLV), vírus da imunodeficiência felina (FIV), Toxoplasma gondii, Cryptococcus spp., herpesvírus felino tipo 1 (FHV-1) and Bartonella spp.] causadores de uveíte felina. A amostra foi positiva na reação em cadeia da polimerase precedida por transcrição reversa em tempo real (RT-qPCR) para FCoV, RT-qPCR e reação em cadeia da polimerase em tempo real (qPCR) para FeLV e qPCR para FIV. O animal foi submetido à eutanásia - devido ao quadro clínico e prognóstico desfavorável. Amostra de líquido cefalorraquidiano (LCR) foi coletada e testada, confirmando a identificação dos mesmos patógenos encontrados no humor aquoso. Linfoma multicêntrico folicular de pequenas células e meningoencefalite piogranulomatosa multifocal foram observados na análise histopatológica. Neste relato, as amostras de humor aquoso e líquido cefalorraquidiano foram eficientes para a detecção de coinfecção por FIV, FeLV e FCoV.

The inoculation eschar of Rickettsia parkeri rickettsiosis in Brazil: Importance and cautions.

Two well characterized tick-borne rickettsioses occur in Brazil. Rickettsia rickettsii caused spotted-fever, transmitted by Amblyomma sculptum and Amblyomma aureolatum, is a severe disease with a high case-fatality rate in the southeastern region of the country. Rickettsia parkeri strain Atlantic rainforest infections transmitted by adult Amblyomma ovale ticks cause a milder non-lethal febrile disease with an eschar (necrosis) at the tick bite site. Clinical diagnosis of rickettsiosis is challenging, particularly during the early stages of the illness when signs and symptoms are non-specific. Since eschar at the tick bite site has emerged as the main clinical feature of mild R. parkeri infections and used to differentiate it from severe R. rickettsii infection, its proper recognition, distinction from other tick bite lesions, and boundaries as a clinical tool must be highlighted. Of importance, eschars induced by Rickettsia must be differentiated from dermatoses caused by other tick-borne skin infections as well from lesions caused by the tick bite itself. We herein highlight information on eschar in rickettsial diseases in Brazil and discuss the need for further research on its clinical relevance and application in the diagnosis of spotted fever caused by R. parkeri strain Atlantic rainforest. In particular, we draw attention to diagnosis of other febrile diseases in the presence of concomitant tick bites.

Seasonal dynamics of Amblyomma sculptum: a review.

BACKGROUND: Amblyomma sculptum is a hard tick that is associated with domestic animals and the transmission of Brazilian spotted fever. This association has motivated several field studies on this ixodid tick within its distribution area in South America. Thorough knowledge of the seasonal dynamics of A. sculptum in different ecological scenarios is required in order to better understand the biological characteristics of this tick and develop techniques for the control and prevention of diseases transmitted by this vector. In this article, we systematically review the seasonal dynamics of A. sculptum and tick collection methodology. METHODS: A systematic search of the Scopus, Web of Science, PubMed and Scielo databases was carried out for articles (including dissertations and theses) on the population dynamics of A. sculptum. The inclusion criterion was the report of seasonal dynamic studies on A. sculptum through surveys carried out for at least 1 year with, as methodology, tick collection in the environment and/or tick count/collection on A. sculptum primary hosts (horses or capybaras). Studies carried out before the reclassification of Amblyomma cajennense sensu lato in 2014, which referred to Amblyomma cajennense in areas where it is currently known that only A. sculptum occurs, were also included. Articles meeting the inclusion criterion, but not available in online databases, were also added based on the authors' experience on the subject. Sixteen articles and one thesis were selected for inclusion in this systematic review. RESULTS: Most of the studies were carried out in the southeastern region of Brazil, with a few also carried out in the northeast, center-west and south of Brazil and northwest of Argentina. Five techniques/methods were applied across these studies: CO2 traps, dragging, flagging, visual searches and tick counting on animals, used alone or in combination. CONCLUSION: Seasonal dynamics of A. sculptum was found to be similar in almost all of the areas studied, with larvae predominating during the autumn, nymphs in the winter and adults in the spring and summer.

Immunophenotypical and pathological changes in dogs experimentally infected with Ehrlichia canis.

Canine monocytic ehrlichiosis (CME) is one of the most important tick-borne diseases worldwide, with multisystemic presentations. Immune dysregulation has been proposed as the primary mechanism involved in its pathogenesis and in tissue injury in dogs with CME. Experimental infection of German Shepherd dogs in the present study demonstrated that CME caused marked pathological changes in their lymph nodes and spleen, and also gave rise to mononuclear infiltration in organs and tissues. Immunophenotyping of cells in lymph nodes, spleen and injured tissues highlighted differences in lymphocyte subsets, local expression of immunoglobulin subclasses and MHCII molecules between infected and control dogs. These findings suggest that the immunophenotypic and immunopathological changes in dogs with acute experimental CME are related to Th1 bias and compartmentalized immune response.

Comparing scapular morphology of Amblyomma sculptum and Amblyomma dubitatum nymphs allows a fast and practical differential diagnosis of ticks in highly infested areas with dominance of these two species.

Rickettsia rickettsii infection causes the highest human fatality rate among all Rickettsia species of the world and is endemic in Southeast Brazil. In this part of the country most human spotted fever cases are related to unnaturally high populations of ticks, usually a mix of two species, Amblyomma dubitatum Neumann and Amblyomma sculptum Berlese and their local host, capybara (Hydrochoerus hydrochaeris). At the same time, an increase in the number of SF notifications as well as its urbanization was observed, and a better characterization of disease epidemiology is mandatory for control measures and to halt its expansion. It was recently noticed in southeast Brazil that SF endemic areas were characterized by overgrowth populations of A. sculptum and decreased populations of A. dubitatum. Hence, characterization of areas with potential to endemicity, eco-epidemiological studies and control measures may rely on the evaluation of A. sculptum/A. dubitatum rate. However, in potentially endemic scenarios, discriminating the two tick species, particularly the nymphs considered the main vector stage, is a challenge in face of several hundreds to thousands of ticks that should be examined for quantitative studies. We herein present additional morphological features to an existing identification key for Amblyomma nymphs that considerably diminishes the labor to distinguish nymphs of these two tick species. Specifically, the oval-shaped scutum of A. dubitatum and a conspicuous scapula of A. sculptum are prominent discriminating features.

Ticks on humans in an Atlantic rainforest preserved ecosystem in Brazil: Species, life stages, attachment sites, and temporal pattern of infestation.

We herein describe exposure and tick attachment to researchers and field staff within the greatest preserved inland Atlantic rainforest, located in Brazil, over a non-consecutive period of five years. Overall, 433 ticks from five species were collected, Amblyomma coelebs (n = 281), Amblyomma brasiliense (n = 79), Amblyomma incisum (n = 43), Amblyomma ovale (n = 4), Haemaphysalis juxtakochi (n = 4). Clusters of larvae belonged to the genus Amblyomma (n = 21) and Haemaphysalis (n = 1). Both Haemaphysalis and Amblyomma species were observed crawling on humans but only ticks from the latter genus were found attached. Most recovered ticks (59%) were found attached and, whereas A. brasiliense was the main host-seeking tick species in the forest, A. coelebs nymphs were the ones that overwhelmingly attached to humans (70% of all attachments). At the same time only 0.4% of human bites were of A. ovale, the Rickettsia parkeri strain Atlantic rainforest vector tick in Brazil. Tick attachment sites were recorded for 132 ticks and lower/upper limbs and the trunk were more parasitized than the head/neck. Tick bites were recorded throughout the year; while larvae did not show an evident seasonal pattern, nymphs attached to humans mainly in autumn and winter and the few adult bites were recorded in spring. Our results highlighted A. coelebs nymphs as major human-biters and evidenced the necessity of studies that discern human tick bites that occur after exposure to host-seeking ticks from those that occur after tick displacement from hosts that carry ticks to human dwellings.

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.

Rhipicephalus microplus and Amblyomma sculptum (Ixodidae) infestation of Nellore cattle (Bos taurus indicus) in a farm of the Brazilian Cerrado: seasonality and infestation patterns.

We herein describe zebuine cattle tick infestation in a farm in southeast Brazil with an examination accurate enough to detect tick immatures and species other than R. microplus. Cattle were inspected monthly for ticks from May 2015 to May 2017 and 7604 ticks were collected along 276 bovine inspections. Rhipicephalus microplus was the dominant species (7197 specimens, 94.5% from the total), but Amblyomma sculptum was also collected (407/5.5%). Horse tick infestations were evaluated for comparison purposes of A. sculptum infestations of a primary host sharing pastures with bovines. Ticks were counted on the left side of 4-12 horses every 3 months from October 2015 to October 2017. Overall, 68 horse inspections were performed and 1702 ticks were collected: Dermacentor nitens (805 specimens/47.3% of the total), A. sculptum (733/43.1%) and R. microplus (164/9.6%). Overall mean tick abundance on bovines was low if compared to that of taurine cattle and counting revealed four annual generations of R. microplus. The interval between infestation peaks was 3 months, irrespective of the season, and an increase in tick counts from spring onward, as described in the south of Brazil, was not seen. Amblyomma sculptum infestation abundance was minor but constant and in high prevalence. Cattle infestation with A. sculptum seems to depend on pasture sharing with other domestic and wild hosts that are its primary hosts and provide engorged females to complete their life cycle. The impact of such tick sharing among several host species on tick-borne pathogen transmission remains to be elucidated.

Diversity of free-living ticks and serological evidence of spotted fever group Rickettsia and ticks associated to dogs, Porto Velho, Western Amazon, Brazil.

Rondônia is the only state in the North Region of Brazil to have registered confirmed cases of Brazilian Spotted Fever (BSF). The present study investigated the epidemiological cycle of Rickettsia spp. by surveying free-living ixodofauna and tick parasitism of dogs in the municipality of Porto Velho, Rondônia State. Ticks and dogs were tested for the presence of Rickettsia spp. DNA and dog serum was tested for reactivity to anti-Rickettsia spp. antibodies. Tick collection and dog blood sampling were performed in peri-urban and rural environments at 11 locations. Eight free-living Amblyomma species and one Haemaphysalis species were collected: A. scalpturatum, A. naponense, A. oblongoguttatum, A. coelebs, A. latepunctatum, A. pacae, A. ovale, Amblyomma sp., and H. juxtakochi. Three tick species were found parasitizing dogs: Rhipicephalus sanguineus sensu lato, A. oblongoguttatum and A. ovale. Molecular analysis did not identify the presence of the gltA gene fragment in any tick specimen. Results from an indirect immunofluorescent assay (IFA) showed that 20.8% of peri-urban and 15.4% of rural dog sera exhibited reactivity to Rickettsia rhipicephali, Rickettsia amblyommatis, Rickettsia bellii and Rickettsia parkeri antigens. Antibody prevalence in dogs was 16.4%. This study is the first to describe the prevalence of Rickettsia spp. infection in dogs from Porto Velho municipality. Our findings enhance current knowledge of Rickettsia spp. circulation in the Western Amazon.

Molecular detection of a Borrelia sp. in nymphs of Amblyomma brasiliense ticks (Acari: Ixodidae) from Iguaçu National Park, Brazil, genetically related to Borrelia from Ethiopia and Côte d'Ivoire.

Gram-negative spirochetes of the genus Borrelia are transmitted to vertebrate hosts through the tick bite during blood intake. Pathogenic Borrelia species may cause relapsing fever or Lyme borreliosis in humans. Our study aimed to molecularly detect and characterize bacteria of this genus in ticks collected in the Iguaçu National Park, located in southern Brazil. Ticks were collected from the environment (free living) and from hosts from May 2015 to July 2017. In total, 829 ticks were tested, being 741 from the environment and 88 from hosts; 128 ticks were larvae, 523 were nymphs, and 178 were adults (80 males and 98 females). The species identified were: Amblyomma brasiliense (42.9 %), Amblyomma coelebs (16.8 %), Amblyomma sp. (15.0 %), Amblyomma incisum (10.3 %), Amblyomma ovale (8.7 %), Haemaphysalis juxtakochi (5.5 %), Rhipicephalus microplus (0.5 %), Amblyomma longirostre (0.2 %), and Rhipicephalus sanguineus sensu lato (0.1 %). DNA extraction was performed with pools of larvae or nymphs, or individually with adults, for a total of 394 samples. The PCR technique used to detect Borrelia DNA was performed with two rounds of amplification reactions targeting a segment of the flagellin B gene (flaB). Amplification occurred in only one DNA sample, which was obtained from nymphs of A. brasiliense collected from the vegetation of a trail. The nucleotide sequence analysis revealed 90.8 % identity to a sequence of Borrelia sp. from Côte d'Ivoire, and 89.1 % identity to a sequence from Ethiopia. Phylogenetic analysis revealed that the Borrelia sequence from A. brasiliense was distinct from the Borrelia species of the groups belonging to Lyme borreliosis, relapsing fever and the one associated with reptile and echidna as hosts. The sequence is likely from a putative new species of Borrelia and was detected for the first time in A. brasiliense ticks.

Free-living ticks (Acari: Ixodidae) in the Iguaçu National Park, Brazil: Temporal dynamics and questing behavior on vegetation.

Basic knowledge of species, ecological preferences and behavior of ticks in preserved rainforests are scanty. We herein describe species richness, seasonal activity, altitude influence and questing height of ticks along 3375 m of animal trails within the largest remain of inland Atlantic rainforest in Brazil, the Iguaçu National Park (INP). Altogether, 2954 ticks from nine tick species were collected; Amblyomma brasiliense Aragão (49.09% of the specimens), Amblyomma coelebs Neumann (29.08%), Amblyomma incisum Neumann (12.49%), Haemaphysalis juxtakochi Cooley (5.21%), Amblyomma ovale Koch (2.64%), Amblyomma longirostre Koch (0.20%), Ixodes fuscipes Fonseca (0.17%), Ixodes loricatus Neumann (0.07%) and Amblyomma dubitatum Neumann (0.03%) (Ixodida: Ixodidae). There was an evident seasonal influence on tick host-questing activity, with each tick stage prevailing in a season before the following one, and a general trend of one tick generation per year. Adult tick questing height mode on vegetation showed a correspondence between tick species and preferred host size and height. Adult ticks quested higher than immatures, but several larval clusters were found high enough to seek for large-sized hosts as well. Nymphal and adult tick questing height increased significantly at higher altitudes within the park. Amblyomma incisum and A. coelebs were more abundant at higher and lower altitudes, respectively. The knowledge on tick species richness, ecological preferences and behavior herein obtained provides baseline information to understand tick-borne disease epidemiology occurring at landscapes under a strong anthropogenic impact.

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.

Microhabitat determines uneven distribution of Amblyomma parvum but not of Amblyomma sculptum ticks within forest patches in the Brazilian Pantanal.

Environmental distribution of the two most abundant ticks in forest areas in the Brazilian Pantanal was evaluated by CO2 traps methodology in the wet season (peak of adult ticks) of 2012 and 2013. Adults of Amblyomma parvum were concentrated inside agglomerates of Bromelia balansae, in the border of forest patches. Adults of Amblyomma sculptum occurred in similar numbers both in bromeliad clumps and in bromeliad-free areas. Differential distribution of ticks in this habitat could be associated to the frequent use of bromeliad clumps by wild animals (potential hosts) and to the microclimate conditions inside this vegetation in the Pantanal. It is important to verify whether larvae and nymphs of A. parvum have a similar pattern of distribution in the same areas, during the dry season. These stages are more susceptible to desiccation and their principal hosts, non-volant small mammals, also use these bromeliad areas.

Immunopathological findings in a cat with auricular chondritis.

At clinical examination, a 5-year-old male domestic short-haired cat exhibited painful swelling and erythema of the pinnae of both ears. Microscopically, the lesions on both pinnae were composed of diffuse granulomatous chondritis with degeneration and necrosis of the pinnal cartilage. Numerous mast cells were also observed within and surrounding the inflammatory lesion. Immunohistochemistry showed a mixed inflammatory infiltrate characterised by the predominance of macrophages (CD68+, MAC 387+ and Lysozyme+), T lymphocytes (CD3+), some B lymphocytes (CD79α+) and neutrophils. Immunopathological characterisation of the lesion showed a granulomatous inflammation profile and suggests that the morphological changes and immunopathogenesis of auricular chondritis in cats presents a similarity with relapsing polychondritis in 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.