Geographical distribution of Amblyomma cajennense (sensu lato) ticks (Parasitiformes: Ixodidae) in Brazil, with description of the nymph of A. cajennense (sensu stricto)

First Evidence of Ehrlichia minasensis Infection in Horses from Brazil

The genus Ehrlichia includes tick-borne bacterial pathogens affecting humans, domestic and wild mammals. Ehrlichia minasensis has been identified in different animal species and geographical locations, suggesting that this is a widely distributed and generalist Ehrlichia. In the present study, we evaluated Ehrlichial infection in 148 Equidae presented to the Medical Clinic Department of a Veterinary Hospital from a midwestern region of Brazil. Blood samples and ticks collected from the animals were tested by Polymerase Chain Reaction (PCR) for the presence of Ehrlichia spp. A multigenic approach including Anaplasmataceae-specific (i.e., 16S rRNA, groEL, gltA) and Ehrlichia-specific (i.e., dsb and trp36) genes was used for accurate bacteria identification. Sera samples were also collected and evaluated for the detection of anti-Ehrlichia antibodies by indirect fluorescent antibody test (IFA). Possible associations between molecular and serological diagnostics and clinical and hematological manifestations were tested using chi-squared or Fisher’s exact tests. Sequence analysis of the dsb fragment revealed that three horses (2.03%) were exposed to E. minasensis. Sixty-one (41.2%) Equidae (58 equines and three mules), were seropositive for Ehrlichia spp., with antibody titers ranging between 40 and 2560. Seropositivity to ehrlichial antigens was statistically associated with tick infestation, rural origin, hypoalbuminemia and hyperproteinemia (p ≤ 0.05). The present study reports the first evidence of natural infection by E. minasensis in horses from Brazil.

Detection of Ehrlichia sp. in Amblyomma sculptum parasitizing horses from Brazilian Pantanal wetland

Bacteria of the genus Ehrlichia are transmitted by ticks and also are an important cause of infection in wild and domestic mammals. Infection with Ehrlichia spp. has been reported in horses, especially in the USA, Nicaragua and Brazil. In this study, we report the parasitism by Amblyomma sculptum, Rhipicephalus microplus and Dermacentor nitens ticks in horses from a ranch located in south Pantanal wetland. Molecular and serological analyzes to determine infection by Ehrlichia spp. in horses and their respective ticks were carried out. A total of 12 horses were submitted to blood collection to investigate antibodies by indirect immunofluorescence assay (IFA) using Ehrlichia canis crude antigens and to be tested by polymerase chain reaction (PCR) in order to amplify fragments of the 16S rRNA, dsb, groEL and sodB gene of Ehrlichia spp. A total of 164 tick specimens were removed from horses, stored in isopropanol and later identified as D. nitens, A. sculptum and R. microplus. DNA from ticks were extracted and subjected to the same PCR assays to detect Ehrlichia spp. Anti-Ehrlichia spp. antibodies were detected in five/12 (41.7 %) horses by IFA, with antibody titers ranging from 40 to 160. All horse DNA samples were negative for the 16S rRNA, dsb, groEL and sodB of Ehrlichia spp. One A. sculptum female was positive to all target genes of Ehrlichia. This tick was parasitizing an Ehrlichia-seropositive horse with antibody titer of 80. Nucleotide sequences of 16S rRNA, dsb, groEL and sodB genes showed close relationship with different strains of Ehrlichia detected in wild mammals, Amblyomma ticks and horses from Brazil and Argentina. Detection of anti-Ehrlichia sp. antibodies suggests that horses have been exposed to an ehrlichial agent in the Pantanal. Future studies on Ehrlichia infection should be carried out to better elucidate and to bring new information about equine ehrlichiosis, since these animals are important hosts of ticks in the Brazilian Pantanal wetlands.

Ticks and rickettsial exposure in lowland tapirs (Tapirus terrestris) of three Brazilian biomes

This study evaluated ticks and rickettsial exposure in 220 free-ranging lowland tapirs, Tapirus terrestris, from 2006 to 2018 in selected areas of three major biomes of Brazil - Atlantic Forest, Pantanal, and Cerrado. Overall, a total of 5970 tick specimens representing the following nine species were collected from tapirs: Amblyomma brasiliense, Amblyomma coelebs, Amblyomma dubitatum, Amblyomma ovale, Amblyomma parvum, Amblyomma sculptum, Amblyomma triste, Haemaphysalis juxtakochi, and Rhipicephalus microplus. Amblyomma sculptum was the most prevalent and abundant tick species in all three biomes; however, mean intensity values for A. sculptum were significantly lower in Atlantic Forest than in the Pantanal or Cerrado, and at the same time, statistically similar among tapirs from Pantanal and Cerrado. Contrastingly, mean intensity values for A. coelebs were significantly higher in the Atlantic Forest than in the other biomes. The remaining tick species were collected in lower numbers, or were exclusive for one biome, e.g., A. brasiliense and H. juxtakochi only in the Atlantic Forest. A total of 177 blood sera (123 individuals plus 54 recaptures) were collected from tapirs and tested for the presence of reactive antibodies to six Rickettsia species by immunofluorescence assay. Overall, 69% (9/13), 49% (62/126), and 66% (25/38) tapir sera from Atlantic Forest, Pantanal and Cerrado, respectively, were seroreactive to at least one Rickettsia species, with no significant difference between the three areas. Although many tapir sera reacted simultaneously to ≥2 Rickettsia species, Rickettsia parkeri elicited highest % seroprevalence and endpoint titers, and was incriminated as the possible agent involved in a homologous reaction in tapirs from the three biomes, where A. ovale was previously found infected by R. parkeri. In fact, seroconversion to R. parkeri was demonstrated in five tapirs that were captured at least twice during the study. This study demonstrated that tapirs were found to be constantly infested by several tick species in the Atlantic Forest, Pantanal and Cerrado biomes; however, the richness of tick infestations was concordant to the tick species known to be established in each biome. Under natural conditions, lowland tapirs were shown to be exposed to tick-borne spotted fever group rickettsiae.

Survey of ticks and tick-borne agents in maned wolves (Chrysocyon brachyurus) from a natural landscape in Brazil

This study evaluated ticks and tick-borne agents in 104 captures of the maned wolf Chrysocyon brachyurus (50 different individuals and 54 recaptures) in the Serra da Canastra National Park (SCNP), a Cerrado preserved area in southeastern Brazil, from 2005 to 2012. From the 104 capture events, a total of 1,206 ticks were collected on 94 occasions (90.4 %), and identified into five species: Amblyomma tigrinum (77.3 % of all collected ticks), Amblyomma sculptum (16.6 %), Amblyomma ovale (0.1 %), Amblyomma brasiliense (0.1 %), Rhipicephalus microplus (0.1 %), and Amblyomma spp. larvae (5.8 %). Molecular analyses of A. tigrinum adult ticks revealed the presence of 'Candidatus Rickettsia andeanae', Rickettsia parkeri sensu stricto, two different haplotypes of 'Ca. Midichloria sp.', and a Hepatozoon canis haplotype. Molecular analyses of maned wolf blood samples revealed two distinct haplotypes of Hepatozoon spp., one identical to the H. canis genotype that was detected in the A. tigrinum ticks, and a Hepatozoon americanum-like haplotype. None tick or blood samples yielded amplicons through PCR assays targeting the genera Ehrlichia, Anaplasma, Babesia, Rangelia, Cytauxzoon, and Theileria. Maned wolf serum samples were tested by immunofluorescence assay against antigens of five Rickettsia species (R. parkeri, R. rickettsii, R. amblyommatis, R. rhipicephali, and R. bellii) and Ehrlichia canis. Among 78 serum samples (45 captures plus 33 recaptures), 74 (95 %) were reactive to at least one Rickettsia species, with R. parkeri eliciting the highest endpoint titers. Some maned wolves that were recaptured during the study were shown to seroconvert to R. parkeri. Serum-reactiveness to E. canis was detected in 36 % (16/45) maned wolves. During the study, general clinical signs of tick-borne diseases were not found in any of the captured animals, indicating that they were under a good health status in the SCNP, despite of been exposed to ticks (mostly A. tigrinum) and some tick-borne agents (Rickettsia, Hepatozoon, Ehrlichia). The results of the present study might represent baseline data for the conservation of the maned wolf in its natural habitat, which should be used to interpret further studies about ticks and tick-borne diseases in maned wolves within human-modified landscapes.

Bats used as hosts by Amblyomma sculptum (Acari: Ixodidae) in Northeastern Brazil and its implications on tick-borne diseases

Amblyomma Koch, 1844 is distributed worldwide, with ca. 130 species currently recognized. These ticks are vectors of pathogens to animals and humans, including the causative agent of the New World Rocky Mountain spotted fever. Species of the Amblyomma parasitize a wide range of organisms, especially medium and large terrestrial mammals. Here we report for the first time the association of Myotis lavali Moratelli, Peracchi, Dias & Oliveira, 2011, Noctilio albiventris Desmarest, 1818 and Noctilio leporinus (Linnaeus, 1758) as hosts for Amblyomma sculptum Berlese, 1888. The ticks were originally identified as Amblyomma cajennense (Fabricius, 1787), in 2011. However, a later taxonomic review indicated that the species of the A. cajennense complex occurring in the Caatinga is A. sculptum. We also discuss the ecoepidemiological implications of this association.

The Unexpected Holiday Souvenir: The Public Health Risk to UK Travellers from Ticks Acquired Overseas

Overseas travel to regions where ticks are found can increase travellers' exposure to ticks and pathogens that may be unfamiliar to medical professionals in their home countries. Previous studies have detailed non-native tick species removed from recently returned travellers, occasionally leading to travel-associated human cases of exotic tick-borne disease. There are 20 species of tick endemic to the UK, yet UK travellers can be exposed to many other non-native species whilst overseas. Here, we report ticks received by Public Health England's Tick Surveillance Scheme from humans with recent travel history between January 2006 and December 2018. Altogether, 16 tick species were received from people who had recently travelled overseas. Confirmed imports (acquired outside of the UK) were received from people who recently travelled to 22 countries. Possible imports (acquired abroad or within the UK) were received from people who had recently travelled to eight European countries. Species-specific literature reviews highlighted nine of the sixteen tick species are known to vector at least one tick-borne pathogen to humans in the country of acquisition, suggesting travellers exposed to ticks may be at risk of being bitten by a species that is a known vector, with implications for novel tick-borne disease transmission to travellers.

Morphological and molecular characterization supporting Amblyomma mixtum presence in Cuba

Amblyomma cajennense Fabricius, 1787 (Acari: Ixodidae) is a widely distributed tick taxon. Recent studies have reassessed this taxon as a complex of six species. Amblyomma mixtum Koch, 1844 has been suggested by some authors as the only species of this complex that is present in Cuba. Other authors have pointed a niche overlapping for A. mixtum and A. cajennense s.s. in the country. Detailed taxonomic studies on the Cuban species belonging to this complex are needed in order to evaluate their current distribution according to the recent classification. This study aimed to characterize Cuban populations from the A. cajennense complex by using tick samples obtained from 3 occidental provinces and 1 central province of the country. Morphological identification and measurements of the main relevant taxonomic structures were conducted by using Scanning Electron Microscopy. Phylogenetic analyzes were carried out with 16S ribosomal RNA, internal transcribed spacer 2 and the subunit I of mitochondrial cytochrome c oxidase gene sequences. The results of these studies demonstrated that all samples belonged to the species A. mixtum (Koch, 1844). This study constitutes the first molecular characterization of this Amblyomma species in Cuba. Further studies will be necessary in order to corroborate if A. cajennense s.s. is also present in the island.

Molecular epidemiology of leprosy: An update

Molecular epidemiology investigations are notoriously challenging in the leprosy field mainly because the inherent characteristics of the disease as well as its yet uncultivated causative agents, Mycobacterium leprae and M. lepromatosis. Despite significant developments in understanding the biology of leprosy bacilli through genomic approaches, the exact mechanisms of transmission is still unclear and the factors underlying pathological variation of the disease in different patients remain as major gaps in our knowledge about leprosy. Despite these difficulties, the last two decades have seen the development of genotyping procedures based on PCR-sequencing of target loci as well as by the genome-wide analysis of an increasing number of geographically diverse isolates of leprosy bacilli. This has provided a foundation for molecular epidemiology studies that are bringing a better understanding of strain evolution associated with ancient human migrations, and phylogeographical insights about the spread of disease globally. This review discusses the advantages and drawbacks of the main tools available for molecular epidemiological investigations of leprosy and summarizes various methods ranging from PCR-based genotyping to genome-typing techniques. We also describe their main applications in analyzing the short-range and long-range transmission of the disease. Finally, we summarise the current gaps and challenges that remain in the field of molecular epidemiology of leprosy.

Locomotion activity and its effects on the survival of Amblyomma sculptum (Acari: Ixodidae) nymphs under laboratory conditions

The active locomotion of ticks is directly associated with the epidemiology of tick-borne diseases, as it has important implications for the interaction of ticks with their hosts and their dispersion in the environment. In an attempt to elucidate the factors involved in the dispersion of Amblyomma sculptum, the present work aimed to characterize different aspects of the active locomotion of A. sculptum nymphs under laboratory conditions. To this end, nymphs were placed on a string at a 70° inclination and their walking activity was recorded daily along with their survival period. During their lifetime, ticks walked an average of 110 m. Their locomotion was not in a straight line and nymphs changed direction 142 times throughout their lifetimes. The mean distance walked per experimental day was 1.8 m, while the average walking distance before changing direction was 52 cm. The distance walked per experimental day reduced over time. The survival of ticks was affected by walking; resting nymphs survived for over 6 months, while the survival of those that walked daily was reduced to approximately 62 days. The results showed that A. sculptum nymphs were able to cover distances of over 100 m throughout their lifetimes, but they walked short distances at a time and constantly changed direction. This behavior indicates that ticks are not able to disperse over long distances by means of active locomotion.

Maintenance of the infection by Rickettsia amblyommatis in Amblyomma cajennense sensu stricto ticks and evaluation of vector competence

Rickettsia amblyommatis has been reported infecting various tick species throughout the western hemisphere, including Amblyomma cajennense sensu stricto (s.s.). The present study aimed to evaluate whether R. amblyommatis can be maintained by transovarial transmission and transstadial passage in A. cajennense s.s. ticks, and whether these ticks are competent vectors of this rickettsial agent. We selected engorged females that were naturally infected or uninfected by R. amblyommatis, and reared their offspring (infected and control groups, respectively). Immature ticks were allowed to feed on guinea pigs, whereas adults fed on rabbits. All stages and individuals of each generation of the infected group yielded rickettsial DNA, which was not detected in any tick from the control group. No host from the control group seroconverted to R. amblyommatis. Among 16 guinea pigs and eight rabbits infested with R. amblyommatis-infected ticks, only one guinea pig seroconverted to R. amblyommatis. Some unfed adult ticks of the infected group were dissected, and DNA was extracted from their salivary glands and from their carcasses. DNA of R. amblyommatis was detected in all carcasses, but not in the salivary glands. Results of this study indicate very low vector competence of A. cajennense s.s. for R. amblyommatis. Previous studies reported domestic animals with high titers to R. amblyommatis in areas where these animals are naturally infested chiefly by A. cajennense s.s. ticks. One may consider that the vector competence of A. cajennense s.s. for R. amblyommatis could vary among tick populations and/or rickettsial strains.

Characterization of the complete mitochondrial genome of Amblyomma ovale, comparative analyses and phylogenetic considerations

In this study, we sequenced two complete mitochondrial genomes of Amblyomma ovale, a tick of public health importance. Sequencing two distinct individuals, the resulting mitochondrial genomes were 14,756 and 14,760 bp in length and maintained the same gene order previously reported in Amblyomma. These were combined with RNA-seq derived mitochondrial sequences from three additional species, Amblyomma aureolatum, Amblyomma maculatum, and Amblyomma moreliae, to carry out mitogenome comparative and evolutionary analyses against all previously published tick mitochondrial genomes. We described a derivative genome rearrangement that isolates Ixodes from the remaining Ixodidae and consists of both a reverse translocation as well as an event of Tandem Duplication Random Loss. Genetic distance analyses indicated that cox2, nd1, nd5, and 16S are good candidates for future population studies in A. ovale. The phylogenetic analyses corroborated the utility of complete mitochondrial genomes as phylogenetic markers within the group. This study further supplements the genome information available for Amblyomma and facilitates future evolutionary and population genetic studies within the genus.

Mapping Brazilian spotted fever: Linking etiological agent, vectors, and hosts

Brazilian spotted fever (BSF) is a highly lethal disease in southeastern Brazil. BSF is caused by the bacterium Rickettsia rickettsii and is transmitted by the bites of the tick of the genus Amblyomma. The spatial distribution of BSF risk areas is not well known in the country given the complexity of the transmission cycle. This study used the ecological niche modeling (ENM) approach to anticipate the potential distribution of the etiological agent (Rickettsia rickettsii), vectors (Amblyomma sculptum and A. dubitatum), and hosts (Hydrochoerus hydrochaeris, Didelphis aurita, and D. marsupialis) of BSF in Brazil. We compiled occurrence records for all vectors, hosts, and BSF from our own field surveillance, online repositories, and literature. ENM identified BSF risk areas in southeastern and southern Brazil, and anticipated other dispersed suitable areas in the western, central, and northeastern coast regions of Brazil. Tick vectors and mammalian hosts were confined to these same areas; however, host species showed broader suitability in northern Brazil. All species ENMs performed significantly better than random expectations. We also tested the BSF prediction based on 253 additional independent cases identified in our surveillance; the model anticipated 251 out of 253 of these independent cases. Background similarity tests comparing the ENMs of R. rickettsii, tick vectors, and mammalian hosts were unable to reject null hypotheses of niche similarity. Finally, we observed close coincidence between independent BSF cases, and areas suitable for combinations of vectors and hosts, reflecting the ability of these model pairs to anticipate the distribution of BSF cases across Brazil.

Serosurvey on rickettsiae of the spotted fever group and Rickettsia bellii among dogs in the state of Goiás, Brazil

The purpose of this study was to do a serological survey on three rickettsial species: Rickettsia rickettsii and Rickettsia parkeri, two species of the spotted fever group (SFG) that are considered to be great importance for public health; and Rickettsia bellii, a species of unknown pathogenicity that infects a variety of human-biting ticks. Serum samples from 273 dogs were tested using the indirect immunofluorescence assay (IFA). A total of 52 samples (19.04%) were seropositive for at least one of the three Rickettsia spp. antigens. Thirty-eight (73.07%), twelve (23.07%) and one (1.92%) of these dogs showed homologous reactions to R. bellii, R. rickettsii and R. parkeri, respectively. Our results showed that the seroprevalence of Rickettsia spp. was relatively low. However, the positive serological tests indicated that these dogs had become infected by these agents at some point in their lives. Lastly, our study adds to the previous knowledge on the epidemiology of rickettsiosis in the state of Goiás by doing the first record of detection of anti-R. rickettsii, R. parkeri and R. bellii antibodies by IFA among dogs, thus indicating that these agents may be circulating in the dog population analyzed.

Detection of Amblyomma mixtum (Acari: Ixodidae) in Germany on a Human Traveler Returning From Cuba

The importation of exotic ticks to Germany on infested humans is rarely reported. Here we describe the detection of an Amblyomma mixtum nymph harboring Rickettsia amblyommatis by a tourist returning from a holiday trip to Cuba. Tick infestation may be neglected by tourists. Therefore, careful anamnesis and diagnosis should be carried out when tourists return from tropical and subtropical countries suffering from nonspecific symptoms, such as fever and malaise.

Ectoparasites of small mammals in a fragmented area of the southern Amazonia: interaction networks and correlations with seasonality and host sex

The present work aimed to analyze the ectoparasite-host interaction network and possible differences of this interaction related to two seasonal periods and host sex. During November 2016 and July 2017, non-flying small mammals were captured in 17 forest fragments located in the southern portion of the Amazon biome. We captured 96 individuals belonging to 10 host species that were parasitized with a total of 3668 ectoparasites. Overall, we identified 24 ectoparasite taxa belonging to the mite and insect groups Ixodida (ticks), Mesostigmata, Sarcoptiformes, Trombidiformes (mites), Phthiraptera (lice), and Siphonaptera (fleas). The interaction network between all ectoparasites and hosts showed significant deviation from random, with moderately high specialization index (H2' = 0.80). There was seasonal difference in prevalence for Amblyomma cajennense (Fabricius) sensu stricto (s.s), Amblyomma coelebs Neumann and larvae of Amblyomma. This difference was also found in the mean intensity of infestation of Amblyomma larvae and the mite Tur aragaoi (Fonseca). Only mean intensity of infestation differed in relation to host sex for the species Marmosa constantiae Thomas. Our results demonstrate that specificity between ectoparasites and small mammals in this region is moderately high and that the pattern of aggregation of some ectoparasite taxa differed between two seasons, as well as between sexes in M. constantiae.

Wild carnivores, domestic dogs and ticks: shared parasitism in the Brazilian Cerrado

The increase of contact between natural and rural areas is prominent in Brazil, due to agricultural activities and concern with the environmental conservation. In this context, domestic animals, wild fauna and humans are exposed to mutual exchange of parasites, microorganisms and diseases. We studied tick parasitism of wild carnivores and domestic dogs, and the environmental of questing ticks, in extensive cattle ranch areas intermingled with natural vegetation, and in a natural reserve, both in a region of Cerrado biome, Midwestern Brazil. From 2008 to 2015, we inspected 119 wild carnivores from nine species, and collected six tick species (Amblyomma sculptum, Amblyomma ovale, Amblyomma dubitatum, Amblyomma tigrinum, Dermacentor nitens and Rhipicephalus microplus). The most numerous and infested hosts were Cerdocyon thous, Lycalopex vetulus, Chrysocyon brachyurus, Puma concolor and Conepatus amazonicus. From 139 domestic dogs, we collected A. sculptum, Rhipicephalus sanguineus and R. microplus. From vegetation, samplings resulted in A. sculptum, A. dubitatum, A. ovale, Amblyomma rotundatum and R. microplus, with dominance of A. sculptum. Domestics and wild animals presented high overlapping of infestations by A. sculptum, a generalist and anthropophilic tick species. This tick is the most important vector of the Brazilian spotted fever, a lethal human disease. This fact elicits attention and requires efforts to monitor the presence of pathogens vectored by ticks circulating in this type of agroecosystem, including in other regions of the Brazil, because the most of the natural vegetation remaining have been increasingly immersed in pastures and agricultural matrix.

Rickettsia rickettsii (Rickettsiales: Rickettsiaceae) Infecting Amblyomma sculptum (Acari: Ixodidae) Ticks and Capybaras in a Brazilian Spotted Fever-Endemic Area of Brazil

The bacterium Rickettsia rickettsii is the agent of Brazilian spotted fever (BSF), a highly fatal disease that is transmitted in Brazil mainly by the tick Amblyomma sculptum Berlese, which uses capybaras (Hydrochoerus hydrochaeris Linnaeus) as major hosts. In 2015, we captured nine capybaras in a BSF-endemic area of southeastern Brazil. From each capybara, we collected blood sera that were tested through the immunofluorescence assay using Rickettsia spp. antigens, and A. sculptum ticks, processed for isolation of R. rickettsii through guinea pig inoculation. All capybaras (100%) were seroreactive to Rickettsia spp., with highest titers to R. rickettsii. A total of 166 A. sculptum ticks were macerated and inoculated into nine guinea pigs, from which only one presented high fever and seroconverted to R. rickettsii. Blood from this febrile animal was inoculated into additional guinea pigs (guinea pig passages), which also became febrile and seroconverted, or when euthanized during the fever period, their internal organs (spleen, lung) were shown to contain R. rickettsii DNA. The present rickettsial isolate has been maintained cryopreserved as infected guinea pig organs. There was at least one R. rickettsii-infected tick among the 166 macerated ticks, giving a minimal infection rate of 0.6% (1/166). This infection rate is within the range of previous studies, which reported that only 0.05% to at most 1.28% A. sculptum ticks were infected by R. rickettsii in other BSF-endemic areas. These low infection rates support the low incidence of BSF, despite of A. sculptum being the most frequent human-biting tick in southeastern Brazil.

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.

Epidemiological aspects of Rickettsia parkeri in the Atlantic forest biome of Espírito Santo state, Brazil

Since 2010, a new rickettsiosis caused by Rickettsia parkeri, a species included in the spotted fever group (SFG) and transmitted by the tick Amblyomma ovale, has been described in Brazil. Considering that A. ovale does occur in the Espírito Santo state (ES), the present study aimed at preliminarily describing the epidemiology of R. parkeri in the Atlantic forest of this state. Between June 2016 and September 2018, 33 villages from nine municipalities of the ES were included in a study for the molecular detection and isolation of SFG rickettsiae from adult Amblyomma ticks collected on dogs with free access to the forest. Serologic screenings against SFG rickettsiae in these animals and their owners (humans) were performed through immunofluorescence assay (IFA) using antigens of Rickettsia rickettsii and R. parkeri. Additionally, local health secretariats were informed on clinical manifestations of R. parkeri infection and told to communicate any suspected case. A total of 280 adult ticks were collected and taxonomically classified as A. ovale (n = 152), Amblyomma aureolatum (n = 127) and Amblyomma sculptum (n = 1). Overall, Rickettsia DNA was detected in 12/266 ticks. The sequencing of PCR products revealed that 0.7% (1/144) and 0.8% (1/121) of the analyzed A. ovale and A. aureolatum ticks were infected by R. parkeri strain Atlantic rainforest, respectively, and 8.3% (10/121) of the A. aureolatum ticks infected by Rickettsia bellii. Among the above PCR-positive ticks, only one isolate from one A. aureolatum tick was successfully established in the laboratory. DNA extracted from the third passage of this isolate was designated as strain M9A and molecularly characterized using primers targeting the Rickettsia gltA gene, whose sequence matched 100% the corresponding sequences of R. bellii. Seroprevalence against SFG rickettsiae in sampled dogs (n = 83) was 41% or 57%, depending on the rickettsial antigen (R. rickettsii strain Taiaçu or R. parkeri strain Atlantic rainforest, respectively). A total of 37 (45%) canine sera showed titers to R. parkeri at least fourfold higher than to R. rickettsii antigen. Among humans, 10% (4/41) of the samples reacted to at least one rickettsial antigen, with the highest endpoint titer varying from 64 to 128 for R. rickettsii and R. parkeri; no human serum showed ≥4-fold difference between the highest endpoint titers. Finally, during the study period, suspicions on cases of R. parkeri-rickettsiosis were not informed by the health secretariats. Our results confirm the presence and exposure to R. parkeri strain Atlantic rainforest, associated with two anthropophilic tick species (A. ovale and A. aureolatum) parasitizing domestic dogs with unrestrained access to forest areas. Consequently, the occurrence of R. parkeri infection in humans inhabiting the Atlantic forests of ES should not be discarded.

Epidemiology of capybara-associated Brazilian spotted fever

Background

Brazilian spotted fever (BSF), caused by the bacterium Rickettsia rickettsii, has been associated with the transmission by the tick Amblyomma sculptum, and one of its main hosts, the capybara (Hydrochoerus hydrochaeris).

Methods

During 2015–2019, we captured capybaras and ticks in seven highly anthropic areas of São Paulo state (three endemic and four nonendemic for BSF) and in two natural areas of the Pantanal biome, all with established populations of capybaras.

Results

The BSF-endemic areas were characterized by much higher tick burdens on both capybaras and in the environment, when compared to the BSF-nonendemic areas. Only two tick species (A. sculptum and Amblyomma dubitatum) were found in the anthropic areas; however, with a great predominance of A. sculptum (≈90% of all ticks) in the endemic areas, in contrast to a slight predominance of A. dubitatum (≈60%) in the nonendemic areas. Tick species richness was higher in the natural areas, where six species were found, albeit with a predominance of A. sculptum (≈95% of all ticks) and environmental tick burdens much lower than in the anthropic areas. The BSF-endemic areas were characterized by overgrowth populations of A. sculptum that were sustained chiefly by capybaras, and decreased populations of A. dubitatum. In contrast, the BSF-nonendemic areas with landscape similar to the endemic areas differed by having lower tick burdens and a slight predominance of A. dubitatum over A.sculptum, both sustained chiefly by capybaras. While multiple medium- to large-sized mammals have been incriminated as important hosts for A. sculptum in the natural areas, the capybara was the only important host for this tick in the anthropic areas.

Conclusions

The uneven distribution of R. rickettsii infection among A. sculptum populations in highly anthropic areas of São Paulo state could be related to the tick population size and its proportion to sympatric A. dubitatum populations.

Brazilian spotted fever (BSF), caused by the bacterium Rickettsia rickettsii, is the deadliest tick-borne disease of the New World. In southeastern Brazil, where 489 patients succumbed to the disease from 2001 to 2018, R. rickettsii is transmitted to humans mainly by the tick Amblyomma sculptum, which uses the capybara (Hydrochoerus hydrochaeris) as its main host. During 2015–2019, we captured capybaras and ticks in seven highly anthropic areas of São Paulo state (three endemic and four nonendemic for BSF) and in two natural areas of the Pantanal biome. The BSF-endemic areas were characterized by much higher tick burdens on both capybaras and in the environment, with a predominance of Amblyomma sculptum. In the BSF-nonendemic areas, another tick species, Amblyomma dubitatum, outnumbered A. sculptum. In the natural areas, six tick species were found; however, with much lower numbers than in the anthropic areas. The BSF-endemic areas were characterized by overgrowth populations of A. sculptum that were sustained chiefly by capybaras, and decreased populations of A. dubitatum. Results of this study support the idea that any intervention resulting in a drastic reduction of the A. sculptum population shall eliminate the R. rickettsii infection from the tick population, and consequently, prevent new BSF cases.

Tick-borne pathogens in carthorses from Foz do Iguaçu City, Paraná State, southern Brazil: A tri-border area of Brazil, Paraguay and Argentina

Tick-borne diseases (TBD) constitute an important group of illness affecting animals and humans worldwide. In Brazil, carthorses are frequently exposed to ticks and tick-borne pathogens, leading to impairment of horse performance and imposing restrictions by the international veterinary authorities for the importation of horses. Accordingly, this study has aimed to i) determine the prevalence of the TBD agents Theileria equi, Babesia caballi, Ehrlichia spp., and hemotropic mycoplasmas in carthorses, ii) identify the tick species parasitizing the animals, and iii) determine factors associated with exposure/infection in Foz do Iguaçu City, Parana state, southern Brazil. A total of 103 carthorses were screened for anti-T. equi and anti-Ehrlichia spp. antibodies by indirect fluorescent antibody assays (IFA). Samples were also tested by PCR assays targeting the 18S rRNA gene of T. equi and B. caballi, and 16S rRNA gene of hemoplasmas. Additionally, PCR assays targeting the 16S rRNA, disulfide bond formation protein (dsb) and tandem repeat proteins 36 (trp36) genes of Ehrlichia spp. were also performed. Antibodies to T. equi and Ehrlichia spp. were detected in 43/103 (41.75%; 95% CI: 32.10-51.88%) and 5/103 (4.85%; 95% CI: 1.59-10.97%) horses by IFA, respectively. DNA of T. equi and B. caballi were found in 25/103 (24.27%; 95% CI: 16.36-33.71%) and 10/103 (9.71%; 95% CI: 4.75-17.13%) carthorses, respectively, and all tested negative for Ehrlichia spp. and hemoplasmas. All sequences showed ≥99% identity with multiple T. equi and B. caballi 18S rRNA gene sequences deposited in GenBank. Overall, 191 Dermacentor nitens ticks were collected from 25/103 (24.27%) animals. Carthorses older than 5 years were more likely to be positive for T. equi (p < 0.05). In conclusion, equine piroplasmosis agents are highly prevalent in carthorses from Foz do Iguaçu City. The low prevalence of Ehrlichia spp. found may be due to the absence of Amblyomma ticks infesting animals, which should be further investigated.

Phenology of Amblyomma sculptum in a degraded area of Atlantic rainforest in north-eastern Brazil

Amblyomma sculptum is the principal vector of Rickettsia rickettsii, the main agent of spotted fever rickettsiosis in Brazil. Little information is available regarding the population dynamics of this tick in some regions, including north-eastern Brazil, where cases of spotted fever rickettsioses are increasingly reported. Herein, we studied the phenology of A. sculptum in a rural area in north-eastern Brazil. Ticks were collected from the environment, using dry ice-baited traps, monthly for two consecutive years. In total, 1500 ticks were collected: 94 females (6.3%), 74 males (4.9%), 468 nymphs (31.2%), and 864 larvae (57.6%). All nymphs and females were identified as A. sculptum. Males were tentatively identified as A. sculptum and larvae as Amblyomma spp. Ticks were more numerous during spring and summer, followed by autumn and winter. Peaks of larvae and nymphs were recorded during summer and spring, respectively, whereas adults were more frequently collected in spring. A total of 380 ticks were tested by PCR for the gltA gene of Rickettsia spp., but none of them were positive. While our results revealed a seasonal pattern for A. sculptum in north-eastern Brazil that is distinct from the seasonal pattern in south-eastern Brazil, we caution that the observed pattern could have been biased by the relatively low number of ticks collected. Finally, the absence of Rickettsia-infected ticks does not rule out the possibility that rickettsial organisms are circulating in the study area and further long-term studies are warranted.

Modeling Potential Habitat for Amblyomma Tick Species in California

The Amblyomma genus of ticks comprises species that are aggressive human biters and vectors of pathogens. Numerous species in the genus are undergoing rapid range expansion. Amblyomma ticks have occasionally been introduced into California, but as yet, no established populations have been reported in the state. Because California has high ecological diversity and is a transport hub for potentially parasitized humans and animals, the risk of future Amblyomma establishment may be high. We used ecological niche modeling to predict areas in California suitable for four tick species that pose high risk to humans: Amblyomma americanum, Amblyomma maculatum, Amblyomma cajennense and Amblyomma mixtum. We collected presence data in the Americas for each species from the published literature and online databases. Twenty-three climatic and ecological variables were used in a MaxEnt algorithm to predict the distribution of each species. The minimum temperature of the coldest month was an important predictor for all four species due to high mortality of Amblyomma at low temperatures. Areas in California appear to be ecologically suitable for A. americanum, A. maculatum, and A. cajennense, but not A. mixtum. These findings could inform targeted surveillance prior to an invasion event, to allow mitigation actions to be quickly implemented.

Amblyomma scalpturatum Neumann, 1906 (Acari: Ixodidae): confirmation in Acre State, Brazil, and description of parasitism in a human

Abstract Amblyomma scalpturatum is a tick species that is unique to South America. It is commonly associated with the Amazon biome and has been reported in some Brazilian states. This tick species exhibits host specificity: it parasitizes tapirs and suidae. Its role in transmitting pathogens to humans is still unknown. Amblyomma scalpturatum is known to be a human-biting tick; however, there is only one report showing that humans make suitable hosts for this species. The knowledge of tick fauna is lacking in the Acre State. This study collected free-living ticks with the aim of finding new records in Acre State. Collections were carried out in Amazon forest fragments in Rio Branco municipality. An A. scalpturatum specimen was identified and submitted sequencing of the ITS-2 gene. This study presents the first molecular confirmation of A. scalpturatum collected in situ in Acre State, North Region, Brazil. This study also presents the first record of a successfully completed feeding by an A. scalpturatum nymph on a human host in the North region of Brazil. Further investigation is needed to ascertain the complete life cycle of this tick species, its seasonality in the environment, and its relationship to pathogens and competence to transmit them.

Serologic and molecular survey of Rickettsia spp. in dogs, horses and ticks from the Atlantic rainforest of the state of Bahia, Brazil

Tick-borne spotted fever in Brazil is known to be caused by two agents, Rickettsia rickettsii and Rickettsia parkeri. Nothing was known about these agents in one area of the Atlantic rainforest biome of Bahia state, where during March to June 2016, 356 rural dogs and 69 horses were sampled and their sera were processed through indirect immunofluorescence assay against antigens of R. rickettsii, R. parkeri, Rickettsia amblyommatis and Rickettsia bellii. Ticks collected from these dogs and horses were molecularly tested for the presence of rickettsial DNA. Overall, 16.4% (58/356) dogs and 24.6% (17/69) horses were seroreactive to Rickettsia spp. Five tick species, Rhipicephalus sanguineus sensu lato (s.l.), Amblyomma ovale, A. sculptum, R. microplus, and A. naponense, were collected from dogs, whereas horses were infested by A. sculptum and Dermacentor nitens. A total of 242 ticks from dogs and 62 from horses were analyzed by PCR targeting rickettsiae, which were detected in only 4/27 (14.8%) A. ovale. Fragments of the rickettsial gltA and ompA genes from these four ticks were 100% identical to the Atlantic rainforest strain of R. parkeri. The presence of A. ovale on dogs was positively associated with local canine seroreactivity to R. parkeri. Our results provide evidence for the transmission of R. parkeri strain Atlantic rainforest from A. ovale to domestic dogs within the rural area of Ilhéus, similarly to other areas of the Atlantic rainforest biome of Brazil, where human cases of R. parkeri-caused spotted fever have been reported.

Ticks (Ixodida: Argasidae, Ixodidae) of Brazil: Updated species checklist and taxonomic keys

Ticks are ectoparasites of great medical and veterinary significance in the neotropical region. In Brazil, they are responsible for enormous economic losses to the livestock industry and also for considerable morbidity and mortality in companion animals and humans. Therefore, recognizing the identity of a given species is important, not only from a biodiversity perspective, but also from the medical and veterinary standpoints. The Brazilian tick fauna is one of the most diverse and well-studied in the neotropical region. In the past few years, several new species were discovered and/or recorded for the first time in this country. The main objectives of this study were to provide an updated list of tick species occurring in Brazil and taxonomic keys for their identification. The updated list of Brazilian ticks includes 70 species, 47 in the family Ixodidae and 23 in the family Argasidae. The genera Amblyomma (32 spp.) and Ornithodoros (18 spp.) are the most representative. Updated taxonomic keys for the identification of ticks of Brazil are provided. Finally, the medico-veterinary significance of ticks occurring in this country is briefly discussed.

Epidemiological study of ticks collected from the northern tamandua (Tamandua mexicana) and a literature review of ticks of Myrmecophagidae anteaters

The family Myrmecophagidae contains three anteater species: Tamandua mexicana (Saussure, 1860), Tamandua tetradactyla (Linnaeus, 1758) and Myrmecophaga tridactyla (Linnaeus, 1758). These American anteater species currently face many conservation threats, among which road traffic accidents stand out. Parasitic studies on this family are scarce, and some of them include records of ectoparasites. Specifically for northern tamandua (T. mexicana), there is a lack of studies at population level. The objectives of the present research were to carry out an epidemiological study of tick species and its abundance on road-killed northern anteater specimens and, moreover, to perform a literature review of ticks collected from anteaters of Myrmecophagidae family. Five tick species were identified, including four Amblyomma spp. and Rhipicephalus sanguineus sensu lato, on 23 road-killed anteaters. Tick infestation prevalence was 43% (10/23), with a median tick infestation intensity of 3.5 per anteater (interquartile range 1-13.7). The bibliographic review highlighted the existence of twenty-nine ixodid species recorded on the three anteater species from 14 countries, mainly Brazil. The most common tick species on the Myrmecophagidae family are Amblyomma nodosum, A. calcaratum, A. cajennense sensu lato and A. auricularium. Some of these ixodids were also described as vectors of pathogens. Further studies are needed to evaluate the impact of ticks on anteater fitness, and to assess the role of these mammals as reservoirs of vector-borne diseases.

Comparative Susceptibility of Different Populations of Amblyomma sculptum to Rickettsia rickettsii

The bacterium Rickettsia rickettsii is the etiological agent of Brazilian spotted fever (BSF), which is transmitted in Brazil mainly by the tick Amblyomma sculptum. Herein, larvae and nymphs of six populations of A. sculptum were exposed to R. rickettsii by feeding on needle-inoculated guinea pigs, and thereafter reared on uninfected guinea pigs or rabbits. Two tick populations were exposed to autochthone R. rickettsii strains, whereas four tick populations were exposed to non-autochthone strains. The six geographically different populations of A. sculptum showed different susceptibilities to R. rickettsii, higher among the two tick populations that were exposed to their autochthone R. rickettsii strain. In addition, higher rates of transovarial transmission of R. rickettsii and vector competence success also included the two tick populations that were exposed to autochthone R. rickettsii strains. These results indicate that the susceptibility of A. sculptum to R. rickettsii varies among different tick populations, with a clear bias for higher susceptibility to an autochthone R. rickettsii strain that has already coevolved with a tick population for some time. Our results demonstrated that the R. rickettsii infection induces higher mortality of engorged larvae and nymphs, and tend to reduce the reproductive fitness of engorged females. All together, these results might explain the low R. rickettsii-infection rates of A. sculptum under natural conditions (usually <1%), and indicate that an A. sculptum population should not be able to sustain a R. rickettsii infection for successive tick generations without the creation of new cohorts of infected ticks via horizontal transmission on vertebrate rickettsemic hosts (amplifying hosts). Finally, despite of the ubiquitous distribution of A. sculptum in southeastern and central-western Brazil, most of the populations of this tick species are devoid of R. rickettsii infection. This scenario might be related to two major factors: (i) insufficient numbers of susceptible amplifying hosts; and (ii) lower susceptibilities of many tick populations. While the first factor has been demonstrated by mathematical models in previous studies, the second is highlighted by the results observed in the present study.

The Dynamics of Ticks and Capybaras in a Residential Park Area in Southeastern Brazil: Implications for the Risk of Rickettsia rickettsii Infection

The bacterium Rickettsia rickettsii causes Brazilian spotted fever (BSF), a highly lethal disease that is transmitted by Amblyomma sculptum ticks in areas where capybaras (Hydrochoerus hydrochaeris) are the tick's major hosts. In this study, we evaluated the expansion of a capybara population in a residential park in São Paulo state, and the implications of such expansion to the occurrence of ticks and BSF. The capybara population was quantified during 2004-2013. In 2012, there was a BSF human case in the area, culminating in the complete fencing of the residential park and the official culling of all capybaras. Quantification of ticks in the environment was performed by dry ice traps from 2005 to 2018. Domestic dogs in 2006-2011 and capybaras in 2012 were serologically tested for the presence of anti-R. rickettsii antibodies. Our results show that capybara numbers increased ≈5 times from 2004 (41 capybaras) to 2012 (230 capybaras). Dry ice traps collected A. sculptum and Amblyomma dubitatum. The number of A. dubitatum adult ticks was generally higher than A. sculptum adults during 2005-2006; however, during 2012-2013, A. sculptum outnumbered A. dubitatum by a large difference. During 2016-2018 (after capybara culling), the number of both species fell close to zero. The low numbers of A. sculptum adult ticks during 2005-2006 coincided with relatively low capybara numbers (<80). Thereafter, in 2012, we counted the highest numbers of both A. sculptum ticks and capybaras (230 animals). All 40 canine blood samples were seronegative to R. rickettsii, in contrast to the 48.3% seropositivity (83/172) among capybaras. Our results support that the emergence of BSF in the residential park was a consequence of the increase of the local capybara population, which in turn, provided the increment of the A. sculptum population. Culling the entire capybara population eliminated the risks of new BSF cases.

dos Santos A, Labruna MB, Biondo AW. Ticks and serosurvey of anti-Rickettsia spp. antibodies in wild boars (Sus scrofa), hunting dogs and hunters of Brazil

BACKGROUND

Rickettsia bacteria are responsible for diseases in humans and animals around the world, however few details are available regarding its ecology and circulation among wild animals and human populations at high transmission risk in Brazil. The aim of this study was to investigate the occurrence of ticks and Rickettsia spp. in wild boars, corresponding hunting dogs and hunters.

METHODS

Serum samples and ticks were collected from 80 free-range wild boars, 170 hunting dogs and 34 hunters from southern and central-western Brazil, from the Atlantic Forest and Cerrado biomes, respectively, between 2016 and 2018. Serum samples were tested by indirect immunofluorescent-antibody assay (IFA) to detect IgG antibodies against Rickettsia rickettsii, Rickettsia parkeri, Rickettsia bellii, Rickettsia rhipicephali and Rickettsia amblyommatis. Tick species were identified by morphological taxonomic keys, as previously described. A total of 164 ticks including A. sculptum, A. brasiliense and A. aureolatum were tested in PCR assays for Spotted Fever Group (SFG) Rickettsia spp.

RESULTS

A total of 58/80 (72.5%) wild boars, 24/170 (14.1%) hunting dogs and 5/34 (14.7%) hunters were positive (titers ≥ 64) to at least one Rickettsia species. A total of 669/1,584 (42.2%) ticks from wild boars were identified as Amblyomma sculptum, 910/1,584 (57.4%) as Amblyomma brasiliense, 4/1,584(0.24%) larvae of Amblyomma spp. and 1/1,584 (0.06%) nymph as Amblyolmma dubitatum. All 9 ticks found on hunting dogs were identified as Amblyomma aureolatum and all 22 ticks on hunters as A. sculptum. No tested tick was positive by standard PCR to SFG Rickettsia spp.

CONCLUSIONS

The present study was the concomitant report of wild boar, hunting dog and hunter exposure to SFG rickettsiae agents, performed in two different Brazilian biomes. Wild boar hunting may increase the risk of human exposure and consequently tick-borne disease Wild boars may be carrying and spreading capybara ticks from their original habitats to other ecosystems. Further studies can be required to explore the ability of wild boars to infecting ticks and be part of transmission cycle of Rickettsia spp.

Hosts mobility and spatial spread of Rickettsia rickettsii

There are a huge number of pathogens with multi-component transmission cycles, involving amplifier hosts, vectors or complex pathogen life cycles. These complex systems present challenges in terms of modeling and policy development. A lethal tick-borne infectious disease, the Brazilian Spotted Fever (BSF), is a relevant example of that. The current increase of human cases of BSF has been associated with the presence and expansion of the capybara Hydrochoerus hydrochaeris, amplifier host for the agent Rickettsia rickettsii and primary host for the tick vector Amblyomma sculptum. We introduce a stochastic dynamical model that captures the spatial distribution of capybaras and ticks to gain a better understanding of the spatial spread of the R. rickettsii and potentially predict future epidemic outcomes. We implemented a reaction-diffusion process in which individuals were divided into classes denoting their state with respect to the disease. The model considered bidirectional movements between base and destination locations limited by the carrying capacity of the environment. We performed systematic stochastic simulations and numerical analysis of the model and investigate the impact of potential interventions to mitigate the spatial spread of the disease. The mobility of capybaras and their attached ticks was significantly influenced by the birth rate of capybaras and therefore, disease propagation velocity was higher in places with higher carrying capacity. Some geographical barriers, generated for example by riparian reforesting, can impede the spatial spread of BSF. The results of this work will allow the formulation of public actions focused on the prevention of BSF human cases.

Complex systems as the Brazilian Spotted Fever (BSF), present challenges in terms of modeling and policy development. BSF human cases have been associated with the presence and expansion of the capybara Hydrochoerus hydrochaeris, amplifier host for the agent Rickettsia rickettsii and primary host for the tick vector Amblyomma sculptum. We developed a reaction-diffusion system for the spread of BSF by considering the spatial structure and migration of amplifier hosts to gain a better understanding of the spatial spread of the R. rickettsii and potentially predict future epidemic outcomes. We performed stochastic simulations and numerical analysis to investigate the impact of potential interventions to mitigate the spatial spread of the disease. Our results indicate that as we vary the amount of capybaras’ food sources, the velocity at which the disease advances is roughly proportional to the carrying capacity, hence proportional to the local risk of zoonotic infection. Some geographical barriers, generated for example by riparian reforesting, can generate positive ecological impacts and can impede the spread of BSF to humans.

Diversity of rickettsiae and potential vectors of spotted fever in an area of epidemiological interest in the Cerrado biome, midwestern Brazil

The Brazilian state of Goiás, untouched by spotted fever (SF) until 2012, has subsequently reported cases of the disease in several regions. This study aimed to survey the diversity of potential vectors and rickettsia in areas of Goiás under environmental surveillance or case investigation for SF. Collected specimens were assayed with molecular biology technology using DNA extraction, amplification and sequencing of fragments of the genes gltA, ompA, ompB and sca4 to detect rickettsia in ticks and fleas. Amplification of cytochrome oxidase subunit II and 16S rRNA was performed to assist tick identification. Rickettsia felis (Rickettsiales: Rickettsiaceae) was found in Ctenocephalides felis (Bouché, 1835) (Siphonaptera: Pulicidae). Rickettsia bellii was found in Amblyomma rotundatum Koch, 1844 (Ixodida: Ixodidae) and in Amblyomma cajennense sensu lato. Rickettsia sp. strain NOD was found in Amblyomma nodosum Neumann, 1899. Of the Amblyomma cajennense complex, Amblyomma sculptum Berlese, 1888 was confirmed in the northern, northeast, midwest and southeast regions of Goiás, whereas Amblyomma cajennense sensu stricto (Fabricius, 1787) was found only in the northern region of the state. Amblyomma dubitatum Neumann, 1899 associated with a species of the A. cajennense complex was the most common epidemiological finding, although Rickettsia rickettsii was not detected. This is the first report of Rickettsia sp. strain NOD in Goiás.

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.

Diferenciação morfométrica entre larvas de Amblyomma sculptum Berlese, 1888 e Amblyomma dubitatum Neumann, 1899

RESUMO Os carrapatos estão envolvidos em processos biológicos de uma grande variedade de organismos patogênicos. O gênero Amblyomma é o de maior importância médica, com a espécie Amblyomma sculptum Berlese, 1888 envolvida no ciclo de transmissão da febre maculosa brasileira (FMB). Neste estudo, objetivou-se a validação molecular para uma diferenciação na característica morfométrica e no tamanho de idiossoma de larvas de duas espécies de carrapatos, Amblyomma dubitatum Neumann, 1899 e A. sculptum. Larvas não alimentadas foram coletadas em duas áreas de transmissão para FMB, por meio da técnica de armadilha atrativa de CO2. Foram identificadas em nível de espécie por morfometria comparativa, análise molecular por PCR e sequenciamento genômico, com validação pela análise de concordância pelo teste Kappa. As larvas de A. dubitatum apresentaram um comprimento significativamente maior que as larvas de A. sculptum. Embora nenhuma outra espécie do gênero Amblyomma tenha sido testada neste estudo, essa técnica poderá ser utilizada nos locais onde levantamentos acarológicos prévios, baseados nos estádios de ninfa e adultos, indicaram a presença de apenas A. sculptum e A. dubitatum, geralmente mantidos por capivaras. Digno de nota, essa condição é muito comum ao longo das áreas endêmicas para FMB na região Sudeste do Brasil.

Survey of ticks in French Guiana

In this study, we examine the current pattern of tick diversity and host use in French Guiana, South America, from 97 sampling localities encompassing peri-urban, rural and natural habitats. We collected 3395 ticks, including 1485 specimens from 45 vertebrate species (humans, domestic and wild animals) and 1910 questing specimens from vegetation. Morphological examinations identified 22 species belonging to six genera: Amblyomma (16 species), Rhipicephalus (two species), Ixodes (one species), Dermacentor (one species), Haemaphysalis (one species), Ornithodoros (one species). To facilitate future identification, we produced a bank of pictures of different stages for all these species. Taxonomic identification was then confirmed by molecular characterization of two mitochondrial genes, cytochrome c oxidase CO1 and 16S rDNA. Eleven of the 22 reported species were collected on humans, six on domestic animals and 12 on wild animals. The most widespread tick species collected were A. cajennense sensu stricto and, to a lesser extent, A. oblongoguttatum; both of these species were frequently found on humans. We used these results to discuss the tick-associated risks for human and animal health in French Guiana.

Genetic Diversity of Bartonella spp. in Wild Mammals and Ectoparasites in Brazilian Pantanal

The present work aimed to investigate the genetic diversity of Bartonella in mammals and ectoparasites in Pantanal wetland, Brazil. For this purpose, 31 Nasua nasua, 78 Cerdocyon thous, 7 Leopardus pardalis, 110 wild rodents, 30 marsupials, and 42 dogs were sampled. DNA samples were submitted to a quantitative real-time PCR assay (qPCR). Positive samples in qPCR were submitted to conventional PCR assays targeting other five protein-coding genes. Thirty-five wild rodents and three Polygenis (P.) bohlsi bohlsi flea pools showed positive results in qPCR for Bartonella spp. Thirty-seven out of 38 positive samples in qPCR were also positive in cPCR assays based on ftsZ gene, nine in nuoG-cPCR, and six in gltA-cPCR. Concatenated phylogenetic analyses showed that two main genotypes circulate in rodents and ectoparasites in the studied region. While one of them was closely related to Bartonella spp. previously detected in Cricetidae rodents from North America and Brazil, the other one was related to Bartonella alsatica, Bartonella pachyuromydis, Bartonella birtlesii, Bartonella acomydis, Bartonella silvatica, and Bartonella callosciuri. These results showed that at least two Bartonella genotypes circulate among wild rodents. Additionally, the present study suggests that Polygenis (P.) bohlsi bohlsi fleas could act as possible Bartonella vectors among rodents in Pantanal wetland, Brazil.

Wildlife species, Ixodid fauna and new host records for ticks in an Amazon forest area, Rondônia, Brazil

The objective of this work was to evaluate the diversity of ticks associated with free-living animals and to investigate new host records for ticks. Ticks were collected from animals rescued during the flood of the Jamari River in the municipality of Ariquemes, state of Rondônia, North Region of Brazil. A total of 39 animals were captured, out of which 10 were amphibians, 19 were reptiles and 10 were mammals. A total of 127 ticks of the Amblyomma genus were collected from these animals, distributed among seven species: Amblyomma dissimile, Amblyomma geayi, Amblyomma humerale , Amblyomma longirostre, Amblyomma nodosum , Amblyomma rotundatum and Amblyomma varium. In addition, one specimen of Rhipicephalus (Boophilus) microplus was collected. Among these specimens, 85 were adults and 42 were nymphs, with A. rotundatum being the most prevalent species. An Amblyomma spp. larvae was also collected from a lizard (Uranoscodon superciliosus), and one Amblyomma calcaratum and one Amblyomma dubitatum were recovered from the environment, thus totaling 130 ticks. Among the Ixodidae collected from different hosts, we provide the first report for the species A. rotundatum parasitizing Rhinella major, U. superciliosus, Leptophis ahaetulla, Chironius multiventris, and Mastigodryas boddaerti, as well as of A. humerale parasitizing U. superciliosus, A. geayi parasitizing Choloepus didactylus, and Rhipicephalus (B.) microplus parasitizing Alouatta puruensis.

Modelos potenciales de distribución geográfica y climática del complejo Amblyomma cajennense (Acari: Ixodidae), potencial vector de Rickettsia rickettsii en Colombia

Introducción. Especies del complejo A. cajennense, potenciales vectores implicados en la transmisión de Rickettsia rickettsii en Centro y Suramérica, presentan una amplia distribución geográfica en el Neotrópico. En Colombia el conocimiento sobre las especies de este complejo, su distribución y aspectos de su ecología es incipiente.Objetivo. Explorar la ecología del complejo A. cajennense en Colombia a partir del estudio de su selección de hábitat y la generación de modelos potenciales de distribución geográfica y climática.Materiales y métodos. Registros únicos de presencia de estas garrapatas fueron utilizados en el estudio de patrones de selección del hábitat mediante ENFA y se construyeron modelos de distribución potencial con las metodologías MaxEnt y GARP.Resultados. El complejo A. cajennense se encontró en las cinco regiones naturales de Colombia con 64,71% de los registros procedentes de los departamentos de Antioquia, Cundinamarca y Huila. La selección del hábitat muestra que estas garrapatas seleccionan fuertemente las áreas geográficas (ENFA: 96,03%) de acuerdo con condiciones de isotermalidad y precipitación del trimestre más seco del año. Los modelos de distribución potencial indican idoneidad de hábitat en 31-51% del área del país, dependiendo del algoritmo empleado.Conclusiones. El complejo A. cajennense en Colombia presenta una distribución altamente influenciada por comportamiento de selección del hábitat climático; esta característica facilitó la creación de modelos de distribución. Estudios de campo permitirán validar los modelos presentados y otros estudios genéticos son requeridos en el país para la identificación de especies del complejo y el abordaje de potenciales zonas de hibridación de estas especies.

New records of tick-associated spotted fever group Rickettsia in an Amazon-Savannah ecotone, Brazil

Human rickettsiosis has been recorded in the Amazon Biome. However, the epidemiological cycle of causative rickettsiae has not been fully accounted for in the Amazon region. This study investigates the presence of spotted fever group (SFG) Rickettsia spp. in free-living unfed ticks of the Amblyomma genus. The study was conducted in seven municipalities in Rondonia State, Brazil, where the main biomes are Amazon forest, Brazilian Savannah and their ecotones (areas of ecological tension between open ombrophilous forest and savannah). The following tick species were collected: Amblyomma cajennense (sensu lato) s.l., A. cajennense (sensu stricto) s.s., A. coelebs, A. naponense, A. oblongoguttatum, A. romitii, A. scalpturatum and A. sculptum. A total of 167 adults, 248 nymphs and 1004 larvae were subjected to DNA extraction and polymerase chain reaction (PCR) to determine the presence of SFG Rickettsia spp. PCR-positive samples included: one A. cajennense s.s. female and one A. cajennense s.l. male from a rural area in Vilhena Municipality; 10 nymphs and a sample of larvae of A. cajennense s.l. from a peri-urban area in Cacoal Municipality; and an A. oblongoguttatum adult male from a rural area of Pimenta Bueno Municipality. All sequences obtained exhibited 100% identity with Rickettsia amblyommatis sequences. This is the first confirmation of SFG Rickettsia in an A. oblongoguttatum tick. Furthermore, this is the first record of SFG Rickettsia in the municipalities targeted by this study. These results warn that SFG Rickettsia circulation poses a threat in Rondonia State (among Amazon-Savannah ecotones), and that this threat is increased by the fact that SFG Rickettsia infect a human-biting tick species hitherto unconfirmed as a vector.

Ticks (Acari: Ixodidae) of the state of Amazonas, Brazil

The tick fauna of Brazil is currently composed by 72 species. The state of Amazonas is the largest of Brazil, with an area of ≈ 19% of the Brazilian land. Besides its vast geographic area, only 19 tick species have been reported for Amazonas. Herein, lots containing ticks from the state of Amazonas were examined in three major tick collections from Brazil. A total of 5933 tick specimens were examined and recorded, comprising 2693 males, 1247 females, 1509 nymphs, and 484 larvae. These ticks were identified into the following 22 species: Amblyomma cajennense sensu lato, Amblyomma calcaratum, Amblyomma coelebs, Amblyomma dissimile, Amblyomma dubitatum, Amblyomma geayi, Amblyomma goeldii, Amblyomma humerale, Amblyomma latepunctatun, Amblyomma longirostre, Amblyomma naponense, Amblyomma oblongoguttatum, Amblyomma ovale, Amblyomma rotundatum, Amblyomma scalpturatum, Amblyomma varium, Dermacentor nitens, Haemaphysalis juxtakochi, Ixodes cf. Ixodes fuscipes, Ixodes luciae, Rhipicephalus microplus, Rhipicephalus sanguineus sensu lato. Ticks were collected from 17 (27.4%) out of the 62 municipalities that currently compose the state of Amazonas. The following four species are reported for the first time in the state of Amazonas: A. coelebs, A. dubitatum, H. juxtakochi, and Ixodes cf. I. fuscipes. The only tick species previously reported for Amazonas and not found in the present study is Amblyomma parvum. This study provides a great expansion of geographical and host records of ticks for the state of Amazonas, which is now considered to have a tick fauna composed by 23 species. It is noteworthy that we report 1391 Amblyomma nymphs that were identified to 13 different species.