The survival of Amblyomma sculptum ticks upon blood-feeding depends on the expression of an inhibitor of apoptosis protein.

BACKGROUND: The tick Amblyomma sculptum is the major vector of Rickettsia rickettsii, the causative agent of the highly lethal Brazilian spotted fever. It has been shown that R. rickettsii inhibits apoptosis in both human endothelial cells and tick cells. Apoptosis is regulated by different factors, among which inhibitors of apoptosis proteins (IAPs) play a central role. In the study reported here, we selected an IAP of A. sculptum that has not yet been characterized to assess its role in cell death and to determine the effects of its gene silencing on tick fitness and R. rickettsii infection. METHODS: An A. sculptum cell line (IBU/ASE-16) was treated with specific double-stranded RNA (dsRNA) for either IAP (dsIAP) or green fluorescent protein (dsGFP; as a control). The activity of caspase-3 and the exposure of phosphatidylserine were determined in both groups. In addition, unfed adult ticks, infected or not infected with R. rickettsii, were treated with either dsIAP or dsGFP and allowed to feed on noninfected rabbits. In parallel, noninfected ticks were allowed to feed on an R. rickettsii-infected rabbit. Ticks (infected or not with R. rickettsii) that remained unfed were used as a control. RESULTS: Caspase-3 activity and the externalization of phosphatidylserine were significantly higher in IBU/ASE-16 cells treated with dsIAP than in those treated with dsGFP. The mortality rates of ticks in the dsIAP group were much higher than those in the dsGFP group when they were allowed to feed on rabbits, independent of the presence of R. rickettsii. Conversely, lower mortality rates were recorded in unfed ticks. CONCLUSIONS: Our results show that IAP negatively regulates apoptosis in A. sculptum cells. Moreover, IAP-silenced ticks experienced higher mortality rates following the acquisition of a blood meal, suggesting that feeding may trigger the activation of apoptosis in the absence of this physiological regulator. These findings indicate that IAP is a potential antigen for an anti-tick vaccine.

Do parapatric populations of the ticks Amblyomma tonelliae Nava, Beati & Labruna, 2014 and Amblyomma sculptum Berlese, 1888 (Acari: Ixodidae) hybridize?

This work aimed to determine if the tick species, Amblyomma sculptum and Amblyomma tonelliae, hybridize along their contact zones in Argentina. Free-living adults and nymphs of A. sculptum and A. tonelliae were collected in seven sampling locations of northern Argentina. In four of them, the two species occur in parapatry (possible hybrid zone) whereas in the other three sites, only one species is known to occur. A total of 65 A. sculptum and 65 A. tonelliae from both, allopatric and parapatric populations, were analysed. The nuclear (ITS2) and mitochondrial (COI and 12SrDNA) gene sequences of each tick were amplified and analysed to verify whether or not they could reveal the presence of hybrids among the parapatric samples. No morphological and molecular evidence was found to support the hypothesis of ongoing natural hybridization. Intrinsic postzygotic barriers may be the cause of lack of gene flow between the two species in areas of co-ocurrence. The results can be explained by the length of time the two lineages spent in allopatry since the middle of the Miocene and before their respective distribution range expanded again reaching a narrow secondary contact zone.

Amblyomma ticks in animal carcasses hunted in Mapinguari National Park, Western Amazon, Brazil: New records on species and host-parasite relationships.

Ticks are obligatory parasites and transmit several pathogens to animals and humans. This study aimed to report the parasitism of ticks on carcasses of animals hunted by hunters from communities near Mapinguari National Park, at the shared border of Amazonas and Rondonia states, northern Brazil. The ticks were collected from heads of carcasses of the following animals: South American tapir (Tapirus terrestris), collared peccary (Pecari tajacu) and long-nosed armadillo (Dasypus beniensis). Six Amblyomma tick species were identified: Amblyomma coelebs, Amblyomma naponense, Amblyomma latepunctatum, Amblyomma oblongoguttatum, Amblyomma scalpturatum, Amblyomma triste and Amblyomma spp. The most abundant tick species were A. oblongoguttatum and A. scalpturatum. DNA extraction and polymerase chain reaction (PCR) were performed on all ticks to test for the presence of rickettsial gltA gene fragments, but no amplification was observed. This study reports, for the first time, the parasitism of A. coelebs in the armadillo D. beniensis and the presence of A. triste in the states of Amazonas and Rondonia, updating the tick fauna to 24 and 39 species for these states, respectively.

Ticks (Acari: Ixodoidea) associated with mammals in Colombia: a historical review, molecular species confirmation, and establishment of new relationships.

Ticks are considered the second most important vectors of pathogens worldwide, after mosquitoes. This study provides a systematic review of vector-host relationships between ticks and mammals (domestic and wild) and consolidates information from studies conducted in Colombia between 1911 and 2020. Using the PRISMA method, 71 scientific articles containing records for 51 tick species (Argasidae and Ixodidae) associated with mammals are reported. The existing information on tick-mammal associations in Colombia is scarce, fragmented, or very old. Moreover, 213 specimens were assessed based on morphological and molecular analyses, which allowed confirming eight tick species associated with mammals: Amblyomma calcaratum, Amblyomma dissimile, Amblyomma mixtum, Amblyomma nodosum, Amblyomma ovale, Amblyomma varium, Ixodes luciae, and Ixodes tropicalis. Several tick species are molecularly confirmed for Colombia and nine new relationships between ticks and mammals are reported. This research compiles and confirms important records of tick-mammal associations in Colombia.

Enduring Challenge of Invasive Ticks: Introduction of Amblyomma oblongoguttatum (Acari: Ixodidae) into the United States on a Human Traveler Returning from Central America.

Introduction of exotic tick vectors of bacteria, protozoa, viruses, and filarial parasites into the United States has accelerated in recent years, primarily because of globalization, increased frequency of travel, and a rise in legal and illegal animal trades. We herein report introduction of a live specimen of Amblyomma oblongoguttatum on a human into the United States from Central America, and we review 4 previous similar incidents. This tick species occurs widely in the neotropics, from western and southern Mexico, southwards through Central America, to the northern half of South America. It is a potential vector of bacterial agents of spotted fever group rickettsioses, raising concern that if A. oblongoguttatum ticks become established in this country, they might also be able to carry pathogens of human and veterinary concern. Given the potential for exotic ticks as vectors of numerous pathogens, proper surveillance, interception, and identification of these ticks are vital to protecting human and veterinary health. Rigorous governmental inspections of imported livestock and pet animals at ports of entry and educating human travelers and medical practitioners about the risks should be part of an overall national tick program.

New records of Haemaphysalis leporispalustris in the Transmexican Volcanic Belt province of Mexico with detection of rickettsial infection.

Haemaphysalis leporispalustris is a hard tick species that have been recorded mainly parasitizing rabbits and birds across the Nearctic and Neotropical regions. Particularly in Mexico, most of the records come from historical collection journeys from before the 1960s. In this paper, we bring new geographical records for this species in Mexico to provide the first genetic data in the country through the amplification of the 16S, COI, and 18S genes, and the detection of a rickettsial agent as well.

First Report of the Introduction of an Exotic Tick, Amblyomma coelebs (Acari: Ixodidae), Feeding on a Human Traveler Returning to the United States from Central America.

Introduction of ticks into the United States that can carry disease-causing pathogens to humans, companion animals, and wildlife has accelerated in recent years, mostly due to globalization, frequency of travel, and a rise in legal and illegal animal trades. We hereby report for the first time introduction of a live fully engorged Amblyomma coelebs feeding on a human into the United States from Central America. Amblyomma coelebs is geographically distributed in the Neotropical region and reaches the southern states of Mexico. This species is capable of transmitting a number of pathogens of public health and veterinary importance including spotted fever group rickettsiae, raising concern that A. coelebs, if it became established in the United States, might also be able to carry these pathogens. Considering the risks of exotic ticks as vectors of numerous pathogens and their potential to establish new populations under conducive climatic and habitat conditions, rigorous inspection practices of imported livestock and pet animals at ports of entry are vital. It is also important for travelers and practitioners to develop a heightened awareness of the public health risks associated with the unintended importation of exotic ticks and the potential such parasites have for breaching United States biosecurity defenses.

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

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.

Amblyomma scalpturatum Neumann, 1906 (Acari: Ixodidae): confirmation in Acre State, Brazil, and description of parasitism in a human / Amblyomma scalpturatum Neumann, 1906 (Acari: Ixodidae): confirmação no Estado do Acre, Brasil, e descrição de parasitismo em um humano

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.

Resumo Amblyomma scalpturatum é uma espécie de carrapato que ocorre apenas na América do Sul. Está comumente associada ao bioma da Amazônia e tem sido relatada em alguns estados brasileiros. Esta espécie de carrapato apresenta especificidade a hospedeiros: parasita antas e suídeos. Sua competência em transmitir agentes patogênicos a seres humanos é ainda desconhecida. Amblyomma scalpturatum é também conhecido por picar seres humanos; entretanto, há apenas um relato que evidencie que seres humanos sejam capazes de serem hospedeiros adequados. Ainda existem lacunas no conhecimento sobre a ixodofauna no estado do Acre. Neste estudo foram coletados carrapatos de vida livre com o objetivo de encontrar novos registros para o estado do Acre. Coletas de carrapatos foram realizadas em fragmentos de floresta Amazônica no município de Rio Branco. Um exemplar de A. scalpturatum foi identificado e submetido a sequenciamento do gene ITS-2. Este estudo apresenta a primeira confirmação molecular de A. scalpturatum coletado in situ no estado do Acre, região Norte, Brasil. Este estudo também apresenta o primeiro relato de parasitismo completo de uma ninfa de A. scalpturatum em um hospedeiro humano na região Norte do Brasil. Mais investigações são necessárias para elucidar o ciclo de vida completo dessa espécie de carrapato, a sazonalidade de seus estádios no meio ambiente, sua relação a agentes patogênicos e competência em transmiti-los.

A high gene flow in populations of Amblyomma ovale ticks found in distinct fragments of Brazilian Atlantic rainforest.

The genetic structure of populations of the tick Amblyomma ovale from five distinct areas of the Brazilian Atlantic rainforest was evaluated via DNA sequencing and associated with the presence of domestic dogs acting as hosts at the edge of forest fragments. Ticks were collected from domestic dogs and from the environment between 2015 and 2017. Four collection areas were located in the surroundings and within the Serra do Mar State Park, São Paulo State (23°37'21"S, 45°24'43"W), where dogs were bimonthly monitored along 2 years using camera traps and GSM trackers. To determine the spatial limits of genetic structure, ticks collected upon dogs living near the Serra do Baturié, Ceará State (4°15'40"S, 38°55'54"W) were included as well. A total of 39 haplotypes of 16S rRNA and Cox 1 mitochondrial genes sequences were observed, with 27 of them coming from areas within the Serra do Mar State Park. No haplotype was shared between the Serra do Mar and the Serra do Baturié indicating isolation of tick populations at the scale of 2000 km. Although three different haplotype lineages of A. ovale occurred within the Serra do Mar State Park, no genetic structure was found across the study sites within this park, suggesting high tick gene flow across a range of 45 km. Monitoring data from domestic dogs and wild carnivores showed that these species share the same habitats at the forest edge, with dogs playing a likely limited role in tick dispersal. Our findings have important implications for understanding the genetic structure of wide spread A. ovale along Brazilian rainforest remnants, which can further be associated to tick-borne infectious agents, such as Rickettsia parkeri, and used for predicting future patterns of tick diversity in the Brazilian Atlantic rainforest.

Genetic diversity, population structure and rickettsias in Amblyomma ovale in areas of epidemiological interest for spotted fever in Brazil.

Amblyomma ovale (Ixodida: Ixodidae) Koch, 1844 is widely-reported in the neotropical region and is the main vector in the epidemic cycle of Rickettsia parkeri strain Atlantic rainforest, a bioagent of a milder variety of spotted fever (SF). Because species with wide geographical distributions are known to exhibit variations that influence their vectorial capacity, the present study aimed to analyze genetic diversity and rickettsia infection of A. ovale collected during the investigation and surveillance of SF cases in the Cerrado and Atlantic rainforest (ARF) Brazilian biomes. Samples had their DNA extracted, amplified and sequenced for 16S rDNA, 12S rDNA, cytochrome oxidase subunit II and D-loop markers for tick analyses, as well as the gltA, htrA, ompA and ompB genes for rickettsia detection. Between 11 and 33 A. ovale haplotypes were identified, all of them exclusive to areas within individual analyzed biome areas. The A. ovale populations appeared to be structured, with Cluster I restricted to Cerrado + ARF isolated in Caatinga and Cluster II to ARF continuous area. Rickettsia bellii, R. parkeri strain Atlantic rainforest (first report for Goiás state, Cerrado), Rickettsia asemboensis (first record in A. ovale for Brazil) and Rickettsia felis (first detection in this ixodid) were identified. A. ovale clusters were not associated with rickettsia types.

Genetic structure analysis of Amblyomma mixtum populations in Veracruz State, Mexico.

Amblyomma mixtum Koch, 1844 parasitizes livestock, humans, and wildlife in Mexico. However, information on population genetics for this tick species in the country is missing. Tick samples were collected from livestock in ten regions across the state of Veracruz (22°28'N, 17°09'S, 93°36'E, 98°39'W) to analyze the genetic structure of A. mixtum populations. Ticks were morphologically identified using taxonomic keys. In order to test the intra-specific variability of A. mixtum fragments of the mitochondrial gene 16S-rRNA and cytochrome oxidase subunit 1 (COI) were amplified. Ninety-six sequences were amplified from the 50 specimens' analyzed (96% amplification success). Eleven haplotypes were detected in 16S-rRNA gene and 10 more for COI. Neutrality tests showed negative results in most of the locations analyzed, which is indicative of an excess of recently derived haplotypes. However, these results were not statistically significant. Minimal union network analysis revealed that there is no separation of populations by geography, and that there is an overlap of several haplotypes among diverse populations. Significant genetic differentiation was not detected in the A. mixtum populations sampled in the state of Veracruz, Mexico, this may be due to the frequent movement of livestock hosts. This is the first report on the genetic structure of A. mixtum populations in Mexico.

The Amblyomma maculatum Koch, 1844 (Acari: Ixodidae) group of ticks: phenotypic plasticity or incipient speciation?

BACKGROUND: The goal of this study was to reassess the taxonomic status of A. maculatum, A. triste and A. tigrinum by phylogenetic analysis of five molecular markers [four mitochondrial: 12S rDNA, 16S rDNA, the control region (DL) and cytochrome c oxidase 1 (cox1), and one nuclear: ribosomal intergenic transcribed spacer 2 (ITS2)]. In addition, the phenotypic diversity of adult ticks identified as A. maculatum and A. triste from geographically distinct populations was thoroughly re-examined. RESULTS: Microscopic examination identified four putative morphotypes distinguishable by disjunct geographical ranges, but very scant fixed characters. Analysis of the separated mitochondrial datasets mostly resulted in conflicting tree topologies. Nuclear gene sequences were almost identical throughout the geographical ranges of the two species, suggesting a very recent, almost explosive radiation of the terminal operational taxonomic units. Analysis of concatenated molecular datasets was more informative and indicated that, although genetically very close to the A. maculatum - A. triste lineage, A. tigrinum was a monophyletic separate entity. Within the A. maculatum - A. triste cluster, three main clades were supported. The two morphotypes, corresponding to the western North American and eastern North American populations, consistently grouped in a single monophyletic clade with many shared mitochondrial sequences among ticks of the two areas. Ticks from the two remaining morphotypes, south-eastern South America and Peruvian, corresponded to two distinct clades. CONCLUSIONS: Given the paucity of morphological characters, the minimal genetic distance separating morphotypes, and more importantly the fact that two morphotypes are genetically indistinguishable, our data suggest that A. maculatum and A. triste should be synonymized and that morphological differences merely reflect very recent local adaptation to distinct environments in taxa that might be undergoing the first steps of speciation but have yet to complete lineage sorting. Nonetheless, future investigations using more sensitive nuclear markers and/or crossbreeding experiments might reveal the occurrence of very rapid speciation events in this group of taxa. Tentative node dating revealed that the A. tigrinum and A. maculatum - A. triste clades split about 2 Mya, while the A. maculatum - A.triste cluster radiated no earlier than 700,000 years ago.

Morphological, molecular and phylogenetic characterization of Borrelia theileri in Rhipicephalus microplus / Caracterização morfológica, molecular e filogenética de Borrelia theileri em Rhipicephalus microplus

This study aimed to perform a morphological, molecular and phylogenetic characterization of Borrelia theileri obtained from infected Rhipicephalus microplus in Brazil. Fifty engorged R. microplus females from cattle in the municipality of Seropédica, Rio de Janeiro, were analyzed for spirochetes by hemolymph smear. Macerated eggs and positive ticks, as well as blood from the bovine infested by these ticks, were analyzed the glpQ, flaB and hpt genes by PCR. The PCR products were purified and sequenced for analysis and construction of a phylogenetic tree. Only 2% (1/50) of the ticks generated a positive result by both smear and PCR. The spiral forms (n = 50) had (media ± SD) a mean length of 19.17 ± 4.12 µm, diameter of 0.2935 ± 0.0469 and number of turns 8.44 ± 2.59. Sequence alignments of the three evaluated genes exhibited 98% similarity to B. theileri isolates, occurring in a clade highly related to B. theileri strain KAT. Egg maceration samples were positive for the three evaluated genes, whereas bovine blood was negative by PCR. This is the most detailed characterization of B. theileri in the Americas to-date, presenting morphological, molecular and phylogenetic data, including the transovarial transmission of the spirochete in the host tick.(AU)

O estudo teve como objetivo realizar a caracterização morfológica, molecular e filogenética de Borrelia theileri obtida de Rhipicephalus microplus naturalmente infectado em bovino no estado do Rio de Janeiro, Brasil. Um total de 50 fêmeas de R. microplus ingurgitadas foram analisadas para espiroquetas por meio de esfregaço de hemolinfa. Ovos macerados e carrapatos, assim como sangue de bovinos infectados por esses carrapatos, foram analisados os genes glpQ, flaB e hpt por PCR. Os produtos de PCR foram purificados e sequenciados para análise e construção de uma árvore filogenética. Apenas 2% (1/50) dos carrapatos geraram um resultado positivo tanto pelo esfregaço como pela PCR. As formas espirais (n = 50) apresentaram (média ± DP) comprimento médio de 19,17 ± 4,12, diâmetro de 0,2935 ± 0,0469 e número de voltas de 8,44 ± 2,59. Os alinhamentos das sequências dos três genes avaliados exibiram 98% de similaridade aos isolados de B. theileri, ocorrendo em um clado altamente relacionado à linhagem de B. theileri KAT. As amostras de maceração de ovos foram positivas para os três genes avaliados, enquanto o sangue bovino foi negativo pela PCR. Esta é a mais completa caracterização de B. theileri nas Américas, apresentando dados morfológicos, moleculares e filogenéticos, incluindo a transmissão transovarial da espiroqueta no carrapato hospedeiro.(AU)

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.

Prevalence and risk factors associated with ectoparasite infestation of buffaloes in an Amazonian ecosystem.

BACKGROUND: The water buffalo (Bubalus bubalis) is well adapted in some regions of the Amazon. Of all Brazilian states, Pará contains the largest number of this species, with 510,000 animals, approximately 38% of the Brazilian buffaloes. Despite the socioeconomic importance of bubaline farming in the northern region, little is known about the prevalence of ectoparasites that affect buffalo herds. This study aimed to identify the species of buffalo ectoparasites in the municipality of Santarém, Pará, and to determine possible risk factors related to ectoparasitic infestation. A cross-sectional study was conducted by sampling 60 rural properties and 621 buffaloes for ectoparasites. When present, ectoparasites were collected for subsequent identification. RESULTS: Of all the animals sampled, 18.5% (115/621) had ectoparasites, 7.8% (49/621) had ticks from the species Rhipicephalus (Boophilus) microplus and Amblyomma cajennense (sensu stricto), and 11.5% (72/621) had lice from the Haematopinus tuberculatus species. Six animals presented mixed infestations of ticks and lice. Among the sampled farms, 51.6% (31/60) had at least one animal infested with ectoparasites. The prevalence of ticks and lice on buffaloes was associated with the farm site, with higher prevalence (11.5% ticks, 15.4% lice) in animals at dry land (OR: 16.7 and 5.7 for ticks and lice, respectively) when compared with floodplains (0.5% ticks, 3.4% lice). Buffaloes aged 1 to 12 months had more ticks whereas buffaloes aged 13 to 24 months had more lice (P < 0.05). CONCLUSIONS: Buffaloes bred in the municipality of Santarém present different levels of tick and lice infestation according to the direct influence of Amazon ecosystem characteristics. The floodplain environment, widely used for buffalo farming, contributes toward minor ectoparasite infestations in these animals.

Seasonal dynamics, geographical range size, hosts, genetic diversity and phylogeography of Amblyomma sculptum in Argentina.

The aim of this work was to generate knowledge on ecological aspects of Amblyomma sculptum in Argentina, such as seasonal dynamics, geographical range size, hosts, genetic diversity and phylogeography. Adult and immature A. sculptum ticks were collected in different localities of Argentina to know the geographical range size and hosts. The genetic diversity of this tick was studied through analyses of 16S rDNA sequences. To describe the seasonal dynamics, free-living ticks were monthly collected from October 2013 to October 2015. A. sculptum shows a marked ecological preference for Chaco Húmedo eco-region and "Albardones" forest of the great rivers in the wetlands in the Chaco Biogeographical Province, and for Selvas Pedemontanas and Selva Montana in the Yungas Biogeographical Province. This species has low host specificity, and it has large wild and domestic mammals as principal hosts to both immature and adult stages. Amblyomma sculptum is characterized by a one-year life cycle. Larvae peak in early winter, nymphs peaked during mid-spring, and adults during late summer and mid-summer. The genetic divergence was low and the total genetic variability was attributable to differences among populations. This fact could be associated to stochastics process linked to micro-habitat variations that could produce a partial restriction to gene flow among populations. The geographic regions do not contribute much to explain the A. sculptum population genetic structure, with an ancestral haplotype present in most populations, which gives rise to the rest of the haplotypes denoting a rapid population expansion.

Rickettsial infection in ticks (Acari: Ixodidae) from reptiles in the Colombian Caribbean.

Although more reptiles are illegally traded in Colombia than any other group of animals, for both local and international markets, little is known about ticks associated with reptiles or pathogens associated with these ticks. In this study, ticks were collected from reptiles in Magdalena, Cesar and La Guajira regions in northern Colombia, and identified morphologically using taxonomic keys and molecularly by sequencing of the COI gene. In addition, Rickettsia spp. were detected by PCR amplifying the gltA, 16S rRNA, and sca1 genes. Ticks were identified as Amblyomma dissimile, representing the first record for this species in 17 of the 26 species of reptiles sampled. Additionally, our data expand the distribution range for this tick in Colombia. Rickettsia spp. DNA was detected in 18 ticks (3.6%) from 16 reptiles. Sequence analyses indicated that most of the Rickettsia were members of the R. monacensis clade, most closely related to Rickettsia sp. strain Colombianensi. We detected one tick infected with a Rickettsia with 99% identity to R. bellii.

Contributions to the knowledge of hard ticks (Acari: Ixodidae) in Colombia.

The known tick fauna of Colombia includes 58 species (15 Argasidae and 43 Ixodidae). To add to the knowledge of the biology of ticks in Colombia, hard ticks (Ixodidae) were collected from domestic animals or vegetation during 2014-2016 in 10 of Colombia's Departments. Ticks were identified to species through morphological examinations. Taxonomic identification was confirmed for some specimens by molecular methods, including phylogenetic analyses inferred from three tick genes (cytochrome c oxidase, 16S rDNA, second internal transcribed spacer). A total of 1745 tick specimens encompassing 8 species were collected. Overall, 5 tick species were recorded on cattle [Amblyomma dissimile, Amblyomma mixtum, Dermacentor nitens, Rhipicephalus microplus, Rhipicephalus sanguineus sensu lato (s.l.)], 5 on dogs (Amblyomma maculatum, Amblyomma ovale, Amblyomma varium, R. microplus, R. sanguineus s.l.), 3 on horses (A. mixtum, D. nitens, R. sanguineus s.l.), 3 on donkeys (A. mixtum, D. nitens, R. microplus), 1 on pig (D. nitens), and 2 from vegetation (A. mixtum, A. dissimile). This included the first records of A. mixtum from two Colombian Departments, indicating that the distribution of this tick in Colombia may be broader than currently known. Phylogenetic analyses confirmed that R. sanguineus s.l. specimens from 8 Departments belong to the "tropical species". Moreover, Colombian specimens of A. maculatum formed a large clade with GenBank sequences of A. maculatum and A. triste, although some Colombian specimens grouped with A. maculatum from the United States while others grouped with A. triste from Brazil. Significant polymorphisms were observed between specimens of A. ovale or D. nitens; for the former species, it is noteworthy that two distinct clades were observed. Our study provides new records for 8 tick species parasitizing domestic animals in Colombia, including species with veterinary and medical importance in the Neotropical region, such as R. microplus, R. sanguineus, D. nitens, A. mixtum, and A. maculatum. Noteworthy, we provide the first record of A. varium infesting a domestic mammal.