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The exposure of a research team to chigger mites in southern Chile allowed the first identification of a trombiculid species as vector and reservoir of scrub typhus outside the tsutsugamushi triangle, providing unique insights into the ecology and transmission of this recently discovered rickettsial infection in South America.

Three species of chigger mites are recorded in our collections from four species of cricetid rodents on Chiloé Island (southern Chile, Los Lagos Region), an area endemic to scrub typhus (Orientia sp.). Two species are described as new—Herpetacarus (Abonnencia) eloisae sp. nov. and Quadraseta chiloensis sp. nov. One species, Paratrombicula goffiStekolnikov and González-Acuña 2012, is for the first time recorded on a mammal host (one species of cricetid rodent), and its distribution is extended to the Los Lagos Region of Chile. The genus ProschoengastiaVercammen-Grandjean, 1967 is synonymized with the subgenus Herpetacarus (Abonnencia)Vercammen-Grandjean, 1960, and four new combinations are established: Herpetacarus (Abonnencia) herniosa (Brennan and Jones, 1961), comb. nov., Herpetacarus (Abonnencia) insolita (Brennan and Jones, 1961), comb. nov., Herpetacarus (Abonnencia) macrochaeta (Brennan and Jones, 1961), comb. nov., and Herpetacarus (Abonnencia) antarctica (Stekolnikov and Gonzalez-Acuña, 2015), comb. nov.

Androlaelaps fahrenholzi is a mite with a large distribution and associated with a wide range of hosts. To assess morphometric variation of A. fahrenholzi associated with different host species (Phyllotis xanthopygus and Akodon albiventer, both from Putre, Chile) and localities (Las Chinchillas National Reserve, Fray Jorge National Park, and Llanos de Challe National Park, all in Chile and all from the host Phyllotis darwini), 41 morphological characters of each specimen were measured, and principal component analysis and discriminant analysis were used. Both analyses showed two groups separated for species of rodents. Mites associated with P. xanthopygus are smaller than those of A. albiventer. The analysis by location indicates two groups: group 1 comprises all mites collected from Fray Jorge National Park and Las Chinchillas National Reserve, and group 2 comprises only mites from Llanos de Challe National Park. These results indicate that A. fahrenholzi population can vary between hosts and geographical areas. Molecular analysis would be necessary to validate these results and determine whether they are subspecies or different species., Facultad de Ciencias Naturales y Museo, Centro de Estudios Parasitológicos y de Vectores

More than ever, there is a need to understand how pathogens, vectors and hosts occur temporally and spatially to predict the occurrence of zoonotic outbreaks. Related to this, mites of the Mesostigmata and Trombidiformes orders have the potential to transmit several diseases, yet their information of occurrence, distribution and zoonotic accompanying agents have not been systematically organized. We conducted a systematic review using a combination of words through the Sysrev platform, as well as literature searches in specialised databases to identify global patterns of infections, trends in mite-rodent-pathogen research and existing knowledge gaps. The inclusion criterion was the detection of pathogens in mites, either by molecular or serological techniques or by direct observation under the microscope, which rendered 125 papers. Most works have been carried out in Asia, mainly around the transmission of Orientia tsutsugamushi. Interestingly, co-infections, i.e., the presence of more than one pathogen in an individual, are common in other Acari groups such as ticks. Moreover, this is not the case for Trombidiformes and Mesostigmata as only 4.7 percent of the articles reviewed detected more than one pathogen in these mites. It is important to include a multi-host, multi-vector and multi-pathogen approaches to understand complex systems in disease ecology. A synergy between mite taxonomists, physicians and veterinarians, decision-makers, governmental organisations, and society is needed to address the emergence of mite-borne new or neglected diseases.

Small mammals play an essential role as disseminators of pathogens because they reach high population densities and have ubiquitous distributions. In the Northern Hemisphere rodents are well recognized as reservoirs for tick-borne bacteria of the Anaplasmataceae family and also apicomplexan protozoans. In contrast, South American rodents hosting these microorganisms have been rarely identified. In this study, we collected blood from rodents and marsupials in northern Chile and screened for Anaplasmataceae bacteria and apicomplexan protozoa. Overall, 14.7% of the samples were positive for Babesia, Hepatozoon, and Sarcocystidae using conventional PCR assays targeting the structural 18S rRNA locus (18S). Phylogenetic analyses performed with amplicons derived from 18S and cytochrome c oxidase (COI) gene provided evidence of a Babesia sp. belonging to the Babesia microti group in Phyllotis darwini, and a novel Babesia genotype in P. darwini and Abrothrix jelskii. Furthermore, four novel genotypes of Hepatozoon retrieved from Abrothrix olivacea, P. darwini, and Oligoryzomys longicaudatus, formed independent lineages within a clade that includes additional Hepatozoon spp. detected in South American rodents. Moreover, an incidental finding of a previously detected apicomplexan, herein designated as Sarcocystidae sp., was recorded in Thylamys opossums with a high prevalence, indicating a possible specific association with these mammals. Phylogenetic analysis of Sarcoystidae sp. clearly demonstrated its relatedness to apicomplexans detected in Australian marsupials. Our results expand the range of mammals hosting tick-borne apicomplexans in South America, highlight a novel clade consisting of South American babesias, and report for the first time the B. microti group infecting rodents in the region.

Background Trichinellosis is a zoonotic disease with a worldwide distribution. It is caused by several species of nematodes in the genus Trichinella. Trichinella spp. are transmitted through predation or carrion consumption and occur in domestic and sylvatic cycles. In humans trichinellosis occurs due to the consumption of raw or undercooked, infected meat and is mainly associated with the household slaughter of pigs or the consumption of game animals without veterinary inspection, a cultural practice that is difficult to resolve. Therefore, knowledge of this parasite’s reservoir is relevant for better implementing public health strategies. The aim of this study was to assess the presence of Trichinella sp. in several carnivore and omnivore vertebrates in central-southern Chile. Methods We collected muscle tissue from a total of 53 animals from 15 species and were digested to detect Trichinella larvae which were further identified to species level using molecular techniques. Results We detected Trichinella larvae in Leopardus guigna (Felidae) and Galictis cuja (Mustelidae). We identified the larvae collected from L. guigna as Trichinella spiralis, but we were unable to molecularly characterize the larvae from G. cuja. This is the first record of Trichinella in a native mustelid of South America and the first record of T. spiralis in L. guigna. This study identified two novel hosts; however, further work is needed to identify the role that these and other hosts play in the cycle of Trichinella in Chile.

Myiopsitta monachus is an invasive psittacine with wide distribution due to the pet trade. Its large communal nests and synanthropic nature contribute to its successful colonization of cities, from where it seems to be expanding in range and numbers. This is relevant with regard to pathogens that invasive species may harbor, especially when host populations thrive. We aimed to identify an abundant mite found in invasive monk parakeet chicks that had been collected in Santiago during 2017 and 2018. Through morphological and molecular identification of the 18S ribosomal RNA gene, we confirmed the presence of Ornithonyssus bursa. This was the first report of this mite in Chile. This mite is common in native and invasive monk parakeet populations and may affect other birds, including domestic fowl. Further, this mite bites people and can be a potential vector of pathogens such as bacteria or viruses. We conclude that this parasite was likely introduced with the parakeet and discuss possible ecological, health and economic consequences of this new potential pest. Resumo Myiopsitta monachus é um psitacídeo invasor amplamente distribuído devido ao tráfico de animais selvagens. Os grandes ninhos comunitários construídos e sua condição de espécies sinantrópicas contribuem para a colonização bem-sucedida das cidades, onde parece estar expandindo sua distribuição e número de indivíduos. Isso é relevante, quando se trata de patógenos que os invasores podem abrigar, especialmente quando as populações hospedeiras prosperam. O objetivo deste trabalho foi identificar um ácaro abundante, encontrado em filhotes de periquitos-monge introduzidos em Santiago, Chile, coletados durante 2017 e 2018. Por meio da identificação morfológica e molecular do gene do RNA ribossômico 18S, foi confirmada a presença de Ornithonyssus bursa, sendo o primeiro registro para o Chile. Esse ácaro é comum em populações nativas e introduzidas de periquitos-monge e pode afetar outras aves, incluindo aves domésticas. Além disso, esse ácaro pode picar pessoas e pode ser um potencial vetor de patógenos, como bactérias ou vírus. Conclui-se que esse parasita provavelmente foi introduzido com o periquito e foram discutidas as possíveis consequências ecológicas de saúde e econômicas dessa nova praga em potencial.

Trichinellosis is a zoonosis with worldwide distribution. Several hosts have been recognized around the world; however, there is a lack of knowledge of the role of feral mammals in Chile in its transmission. Herein, we tested muscle samples from 555 individuals among American minks (Neovison vison Schreber, 1777. n = 100) and several myomorph rodent species (Muridae and Cricetidae. n = 455) from southern Chile by artificial digestion to detect Trichinella larvae and identified the larvae at the species level through molecular analyses. Rodents were captured in agricultural and wild protected areas of several administrative regions (hereafter: region), while minks were captured in agricultural areas of the Los Rios region. Trichinella spiralis larvae were detected in a synanthropic black rat (0.24%) of the Nuble region and in seven minks (7%) trapped in agricultural areas of the Los Rios region. The present results suggest that T. spiralis circulation is restricted to synanthropic rodents and minks living in agricultural areas where the parasite circulates among domesticated pigs. This study represents the first record of T. spiralis in a mustelid mammal in South America, increasing the number of feral species that could participate in the reservoir.

Invasive populations are a threat to biodiversity, resulting in the loss of species, and also a threat to human health, participating in the reservoir of diseases. Rodents are among the most important invasive species worldwide. Chile is a country that features island conditions in terms of geography and has been widely invaded by allochthonous rodents. In this mini-review, we updated the literature on macro-parasites infecting both native and invasive rodents and of vector-borne pathogens in continental Chile in order to assess the relative importance of invasive rodents from both ecological and public health points of view. A total of 174 parasite species were found, with Siphonaptera representing the most diverse group. When examining how parasites are shared between native and introduced rodents, the analysis suggests that parasites circulate freely within recipient populations, and are not significantly transmitted from source populations. Further, generalist parasites are typically more prone to being shared between native and introduced rodents. Most zoonotic parasites were reported in invasive rodents, suggesting that these rodents must represent a public health concern. Although several vector-borne pathogens have been reported in rodents or ectoparasites, most of the recently emerging research has illustrated that there is a lack of evidence on rodent–vector-borne zoonoses in most pathogens.

BackgroundFleas are important vectors of pathogenic bacteria that pose public health concerns worldwide, including Rickettsia. Micromammals, and especially rodents, are the main flea hosts, therefore they play a fundamental role in the spread of flea-borne diseases and various species of rodent fleas can also parasitize humans. In addition to this, many rodent species are capable of inhabiting wild environments and adapting to rural and urban environments, which could favor a continuous gradient of transmission between domestic and wild species. The aim of this study was to detect, characterize, and compare Rickettsia spp. from the fleas of micromammals in areas with different human population densities in Chile.MethodsTo determine Rickettsia in fleas of micromammals, we analyzed 1,315 fleas obtained from 1,512 micromammals, which were captured in 29 locations with different human population densities in Chile. We used polymerase chain reaction (PCR) amplification of the gltA, rpoB, and ompB genes to detect Rickettsia in fleas.ResultsThe prevalence of Rickettsia among flea species ranged from 0%–35.1%. Fifteen flea species were found to be Rickettsia-positive. Areas of lower human density have the highest prevalence of Rickettsia. The phylogenetic tree shows two well-differentiated clades. Rickettsia belli is positioned as basal in a clade. Another clade is subdivided into two subclades, and are related to Rickettsia of typhus group.ConclusionsConsidering that fleas are generalist parasites, and that they are frequently found and abundant in rodents, which are closely related to humans, the detection of potential emerging zoonotic pathogens in rodent fleas highlights the risk of infection to humans.

Small mammals play an essential role in the transmission and maintenance cycles of Borrelia spirochetes. In Chile, recent studies have characterized novel Borrelia genotypes in ticks collected from small mammals, a fact that suggests these vertebrates are hosts for spirochetes from this genus. Considering this evidence, the goal of this study was to determine the presence of Borrelia DNA in small mammals inhabiting northern Chile. In winter of 2018, 58 small mammals were captured in five localities. Blood samples were collected from rodents and DNA was extracted to determine the presence of Borrelia DNA by PCR targeting the flaB gene and rrs–rrlA intergenic spacer (IGS). From three individuals (5%), belonging to two rodent species of Cricetidae family (Phyllotis xanthopygus and Oligoryzomys longicaudatus), we retrieved three flaB and two IGS Borrelia genotypes. Phylogenetic analyses performed with both Maximum Likelihood and Bayesian inferences showed that our sequences grouped with homologous genotypes from the relapsing fever and Lyme borreliosis groups. Our findings suggest that P. xanthopygus and O. longicaudatus rodents may play a role as reservoirs for borrelial spirochetes in Chile. Resumo Pequenos mamíferos possuem um papel essencial na transmissão e manutenção de espiroquetas do gênero Borrelia. No Chile, estudos recentes têm descrito novos genótipos de Borrelia em carrapatos, parasitando pequenos mamíferos. Isso sugere que esses vertebrados podem atuar como possíveis reservatórios dessas espiroquetas. Considerando-se essa evidência, o objetivo deste estudo foi determinar a presença de DNA de Borrelia em pequenos mamíferos da região norte do Chile. Durante o inverno de 2018, 58 pequenos mamíferos foram capturados em cinco localidades. Amostras de sangue obtidas a partir dos indivíduos capturados foram submetidas à extração de DNA e ensaios de PCR, para a detecção de Borrelia spp. baseados no gene flaB e espaçador intergênico rrs–rrlA (IGS). A partir de três espécimes (5%) pertencentes a duas espécies de roedores da família Cricetidae (Phyllotis xanthopygus e Oligoryzomys longicaudatus) obtiveram-se três genótipos de Borrelia para o gene flaB e dois para IGS. Análises filogenéticas inferidas, usando-se os métodos Bayesiano e de Máxima Verossimilhança, indicaram que as sequências geradas neste estudo agrupam-se com borrelias do grupo da Febre Recorrente e Borreliose de Lyme. Os achados deste estudo sugerem que roedores P. xanthopygus e O. longicaudatus poderiam atuar como possíveis reservatórios para Borrelia spp. no Chile.

BackgroundScrub typhus in an emerging vector-borne zoonosis, caused by Orientia spp. and transmitted by larvae of trombiculid mites, called chiggers. It mainly occurs within a certain region of the Asia-Pacific, called tsutsugamushi triangle, where rodents are known as the most relevant hosts for the trombiculid vector. The disease has recently been discovered on Chiloé Island in southern Chile. Still, the reservoir(s) and vector(s) of the scrub typhus outside Asia-Pacific are unknown. The aim of the present work was to study the prevalence of chiggers on different rodent species captured in sites identified as probably hot spots of scrub typhus on Chiloé Island in southern Chile.Methodology/Principal FindingsDuring austral summer 2018, rodents were live-trapped in six sites and examined for chigger infestation. During a total of 4,713 trap-nights, 244 rodents of seven species were captured: the most abundant was Abrothrix olivacea. All study sites were rural areas on Chiloé Island, previously identified as localities of probable human infection with scrub typhus. Chiggers were detected on all seven rodent species with a 55% prevalence rate. Chiggers showed low host specificity and varied according to site specific host abundance. We identified trombiculids of three genera. Colicus was the most abundant chigger (93%), prevalent in five of six sites, followed by Quadraseta (7%) and Paratrombicula (7%), which were in only one site. Infestation rates showed site specific differences, which were statistically different using a GLM model with binomial errors.Conclusions/SignificanceThis study firstly reports the presence of different rodent-associated chigger mites in a region with endemic scrub typhus in southern Chile. Colicus and two other genera of mites were found with high infestation rates in sites previously identified as hot spots of scrub typhus, suggesting their role as vectors and reservoirs of this emerging zoonosis in South America.Author SummaryScrub typhus is a chigger-transmitted zoonotic infection, which is endemic in the tsutsugamushi triangle in Asia-Pacific. Recently, a first focus of scrub typhus in South America has been confirmed on Chiloé Island in southern Chile. Still, the vectors of scrub typhus in this region remain unknown. We undertook a survey to study the prevalence of chiggers on different rodent species in areas identified as probable hot spots of scrub typhus on Chiloé Island. The study showed that 55% of rodents were infested by trombiculids. Three chigger genera were identified, of which Colicus was the most abundant. Chiggers showed low host specificity, but spatial differences. This first demonstration of rodent-associated chigger mites in hot spots of scrub typhus suggests their possible role as vectors of this infection in Chile.

Background Scrub typhus is an emerging vector-borne zoonosis, caused by Orientia spp. and transmitted by larvae of trombiculid mites, called chiggers. It mainly occurs within a region of the Asia-Pacific called the tsutsugamushi triangle, where rodents are known as the most relevant hosts for the trombiculid vector. However, the reservoir(s) and vector(s) of the scrub typhus outside Asia-Pacific are unknown. The disease has recently been discovered on and is considered endemic for Chiloé Island in southern Chile. The aim of the present work was to detect and determine the prevalence of chiggers on different rodent species captured in probable sites for the transmission of orientiae responsible for scrub typhus on Chiloé Island in southern Chile and to molecularly examine collected chiggers for the presence of Orientia DNA. Methodology/Principal findings During the austral summer 2018, rodents were live-trapped in six sites and examined for chigger infestation. All study sites were rural areas on Chiloé Island, previously identified as probable localities where human cases acquired the scrub typhus. During a total of 4,713 trap-nights, 244 rodents of seven species were captured: the most abundant was Abrothrix olivacea. Chiggers were detected on all seven rodent species with a 55% prevalence rate. Chiggers showed low host specificity and varied according to site specific host abundance. Three genera of trombiculids were identified. Herpetacarus was the most abundant genus (93%), prevalent in five of the six sites. Infestation rates showed site specific differences, which were statistically significant using a GLM model with binomial errors. Molecular analyses proved that 21 of 133 (15.8%) mite pools were positive for Orientia species, all of them belonged to the genus Herpetacarus. Conclusions/Significance This study firstly reports the presence of different rodent-associated chigger mites positive for Orientia sp., in a region endemic for scrub typhus in southern Chile. Herpetacarus and two other genera of mites were found with high infestation rates of rodents in sites previously identified as probable exposure of scrub typhus cases. A substantial percentage of mite pools were positive for Orientia DNA, suggesting that chigger mites serve as vectors and reservoirs of this emerging zoonosis in South America., Author summary Scrub typhus is a chigger-transmitted zoonotic infection caused by Orientia species, which is endemic to the tsutsugamushi triangle in Asia-Pacific region. Recently, a focus of scrub typhus in South America has been confirmed on Chiloé Island in southern Chile. However, the vectors of scrub typhus in this region remain unknown. We undertook a survey to study the presence of chiggers on different rodent species in areas identified as probable sites of exposure to scrub typhus on Chiloé Island. The study showed that 55% of rodents were infested by trombiculids. Three mite genera were identified, of which Herpetacarus was the most abundant. Chiggers showed low host specificity, but spatial differences. Using molecular techniques, the trombiculid mites were found to be infected with Orientia species. These findings suggest that chigger mites play a role in the life cycle and transmission of this emerging infectious disease in Chile.

This research aimed to determine the presence of paramphistomids in cattle slaughtered in a slaughterhouse of the Ñuble Region of Chile, to identify flukes and to analyze the frequency of these parasites in the Maule, Ñuble, and Biobío administrative regions of Chile. Between October of 2016 and April of 2017, rumens of 494 cattle were examined for flukes in the forestomachs. Worms were identified morphologically and, in addition, molecular analysis of the internal transcriber spacer region 2 of the fluke’s DNA was done and phylogenetic analyses were performed with Bayesian inference in 14 worms. The frequency was analyzed by locality (low- or highlands) and age. The overall frequency was 11.24%. The district with the highest frequency of presentation was Chillán Viejo (30.8%). Districts in the lowlands had similar frequencies to those in the mountain lands (p=0.1). The frequency of flukes was significantly higher in adult animals than in young ones (p

Rattus rattus is a widely distributed, invasive species that presentsan important role in disease transmission, either directly or through vectorarthropods such as fleas. These black rats can transmit a wide variety of pathogens, including bacteria of the genus Bartonella, which can cause diseases in humans and animals. In Chile, no data are available identifying fleas from synanthropic rodents as Bartonella vectors. The aim of this study was to investigate the prevalence of Bartonella spp. in the fleas of R. rattus in areas with different climate conditions and featuring different human population densities. In all, 174 fleas collected from 261 R. rattus captured from 30 localities with different human densities (cities, villages, and wild areas) across five hydrographic zones of Chile (hyper-arid, arid, semi-arid, sub-humid, and hyper-humid) were examined. Bartonella spp. presence was determined through polymerase chain reaction, using gltA and rpoB genes, which were concatenated to perform a similarity analysis with BLAST and phylogenetic analysis.Results: Overall, 15 fleas species were identified; Bartonella gltA and rpoB fragments were detected in 21.2% (37/174) and 19.5% (34/174) of fleas, respectively. A total of 10 of the 15 fleas species found were positive for Bartonella DNA. Leptopsylla segnis was the most commonly collected flea species (n = 55), and it also presented a high prevalence of Bartonella DNA (P% = 34.5%). The highest numbers of fleas of this species were collected in villages of the arid zone. There were no seasonal differences in the prevalence of Bartonella DNA. The presence of Bartonella DNA in fleas was recorded in all hydrographic areas, and the arid zone presented the highest prevalence of this species. Regarding areas with different human densities, the highest prevalence was noted in the villages (34.8% gltA and 31.8% rpoB), followed by cities (14.8% gltA and 11.1% rpoB) and wild areas (7.4% gltA and 14.8% rpoB). The BLAST analysis showed a high similitude (>96%) with four uncharacterized Bartonella genotypes and with two species with zoonotic potential: B. mastomydisand B. tribocorum. The phylogenetic analysis showed a close relationship withB. elizabethae and B. tribocorum. This is the first study to provide evidence of the presence of Bartonella in fleas of R. rattus in Chile, indicating that the villages and arid zone correspond to areas with higher infection risk. Fil: Moreno Salas, Lucila. Universidad de Concepción. Facultad de Ciencias Naturales y Oceanografía. Departamento de Zoología; Chile Fil: Espinoza Carniglia, Mario Virgilio. Universidad de Concepción. Facultad de Ciencias Naturales y Oceanografía. Departamento de Zoología; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; Argentina Fil: Lizama Schmeisser, Nicol. Universidad de Concepción. Facultad de Ciencias Naturales y Oceanografía. Departamento de Zoología; Chile Fil: Torres, L. Gonzalo. Universidad de Concepción. Facultad de Ciencias Naturales y Oceanografía. Departamento de Zoología; Chile. Universidad Austral de Chile; Chile Fil: Silva de la Fuente, María Carolina. Universidad de Concepción; Chile. Universidad San Sebastian.; Chile Fil: Lareschi, Marcela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; Argentina Fil: González Acuña, Daniel. Universidad de Concepción; Chile

The family Trombiculidae is one of the most diverse and cosmopolitan (Walter et al. 2009). In Chile, the family Trombiculidae is represented by six genera associated with reptiles: Eutrombicula Ewing; Microtrombicula Ewing; Paratrombicula GoffWhitaker; Whartonacarus (BrennanJones); Diaguitacarus StekolnikovGonzález-Acuña and Proschoengastia Vercammen-Grandjean and two genera associated with rodents Chilacarus Webb, BennettLoomis and Poliremotus BrennanGoff (StekolnikovGonzález-Acuña 2015).

A new genus and species Callopistiella atacamensis gen. nov. and sp. nov. (Acariformes: Pterygosomatidae) are described from Callopistes maculatus (Squamata: Teiidae) in Chile. In this species, both sexes are characterized by the hypostome without a velum, the chelicerae proximally globose and very thin distally, ending in a movable digit curved outward, the fixed cheliceral digit reduced to a membranous and sparsely serrate structure, presence of seta 2c, tarsus I with seta ft nude and 2 times longer than solenidion ω2; larvae have solenidion ω1 on tarsus I and tibia I without solenidion φ and moderate hypertrichy present around the genital area. Some biological aspects of this new species are discussed.

The family Trombiculidae is one of the most diverse and cosmopolitan (Walter et al. 2009). In Chile, the family Trombiculidae is represented by six genera associated with reptiles: Eutrombicula Ewing; Microtrombicula Ewing; Paratrombicula Goff & Whitaker; Whartonacarus (Brennan & Jones); Diaguitacarus Stekolnikov & Gonzalez-Acuna and Proschoengastia Vercammen-Grandjean and two genera associated with rodents Chilacarus Webb, Bennett & Loomis and Poliremotus Brennan & Goff (Stekolnikov & Gonzalez-Acuna 2015).

A new genus and species Callopistiella atacamensis gen. nov. and sp. nov. (Acariformes: Pterygosomatidae) are described from Callopistes maculatus (Squamata: Teiidae) in Chile. In this species, both sexes are characterized by the hypostome without a velum, the chelicerae proximally globose and very thin distally, ending in a movable digit curved outward, the fixed cheliceral digit reduced to a membranous and sparsely serrate structure, presence of seta 2c, tarsus I with seta ft nude and 2 times longer than solenidion ω2; larvae have solenidion ω1 on tarsus I and tibia I without solenidion φ and moderate hypertrichy present around the genital area. Some biological aspects of this new species are discussed.

ResumenCon el objetivo de analizar la abundancia y distribución de ácaros en la lagartija Liolaemus pictus y su relación con el tamaño corporal y sexo del hospedador, se extrajeron 835 ácaros de 134 individuos de L. pictus capturados en Chile central —regiones de la Araucanía hasta Los Lagos, incluyendo la isla de Chiloé—. Se calculó la prevalencia y abundancia total de ácaros por hospedador y abundancia por zona corporal. Se analizó la relación entre el tamaño corporal del hospedador y la abundancia de ácaros. El 39% de las lagartijas presentó ácaros, identificándose las especies Eutrombicula araucanensis (prevalencia34.3%) y Pterygosoma sp. (prevalencia 8.2%). No se encontró asociación significativa entre tamaño corporal del hospedador ni el sexo con la abundancia de ácaros. Las zonas corporales del hospedador mayormente parasitadas fueron la femoral y flanco, aunque la zona femoral estuvo parasitada solamente por E. araucanensis. Se plantea que la forma de las escamas puede ser el factor que esté influenciando directamente la distribución corporal de estas especies de ácaros en L. pictus en Chile.AbstractIn order to analyze the abundance and distribution of mites in the lizard Liolaemus pictus and its relationship with the body size and sex of the host, 835 mites from 134 specimens of L. pictus captured in central Chile —Araucanía Region to Los Lagos, including Chiloé Island— were studied. Prevalence, total abundance and abundance for each body region of the host were calculated. The relationship between the host body size and abundance of mites was analyzed. Mites were found in 39% of lizards, identifying 2 species Eutrombicula araucanensis (prevalence 34.3%) and Pterygosoma sp. (prevalence 8.2%). No significant association between host body size, sex and abundance of mites was found. The host body areas that had higher abundance of mites were: femoral and flank, although the femoral area was only parasitized by E. araucanensis. We propose that the shape of the lizard scales could be the factor that is directly influencing the body distribution of these species of mites in L. pictus in Chile.