Ticks (Acari: Ixodidae) on resident and migratory wild birds in Orinoquia region, Colombia

Several species of hard ticks, including those of the genera Ixodes, Haemaphysalis, Amblyomma, and Rhipicephalus, are of medical and veterinary importance and have been reported in association with Neotropical wild birds. Colombia, known for its great bird diversity, has 57 confirmed tick species. However, there are few studies on the association between wild birds and ticks in Colombia. The Orinoquia region, a migratory center in Colombia, provides a unique opportunity to study wild bird-tick associations and their implications for tick-borne disease dynamics. Our study, conducted between October and December 2021, aimed to identify hard ticks infesting resident and migratory wild birds in the department of Arauca and to assess the presence of bacteria from the genera Anaplasma, Borrelia, Ehrlichia, Rickettsia, and piroplasms. A total of 383 birds were examined, of which 21 were infested. We collected 147 ticks, including Amblyomma dissimile (larvae), Amblyomma longirostre (nymphs), Amblyomma mixtum (adults), and Amblyomma nodosum (larvae and nymphs). We did not detect bacterial DNA in the tested ticks; however, piroplasm DNA was detected in ticks from three of the infested birds. Of the 21 bird-tick associations, six are new to the Americas, and interesting documentation of piroplasm DNA in A. longirostre, A. nodosum, and A. dissimile ticks from wild birds in the region. This study provides valuable insights into the ticks associated with wild birds and their role in the dispersal of ticks and pathogens in Colombia, enhancing our understanding of tick life cycles and tick-borne disease dynamics.

Dermacentor (Indocentor) auratus Supino 1897: Potential geographic range, and medical and veterinary significance

Dermacentor (Indocentor) auratus Supino, 1897 occurs in many regions of Southeast Asia and South Asia. In many regions of Southeast Asia and South Asia, targeted tick sampling and subsequent screening of collected D. auratus ticks have detected pathogenic bacteria and viruses in D. auratus. These disease-causing pathogens that have been detected in D. auratus include Anaplasma, Bartonella, Borrelia, Rickettsia (including spotted fever group rickettsiae), African swine fever virus, Lanjan virus, and Kyasanur forest disease virus. Although D. auratus predominantly infests wild pigs, this tick is also an occasional parasite of humans and other animals. Indeed, some 91 % of human otoacariasis cases in Sri Lanka were due to infestation by D. auratus. With the propensity of this tick to feed on multiple species of hosts, including humans, and the detection of pathogenic bacteria and viruses from this tick, D. auratus is a tick of medical, veterinary, and indeed zoonotic concern. The geographic range of this tick, however, is not well known. Therefore, in the present paper, we used the species distribution model, BIOCLIM, to project the potential geographic range of D. auratus, which may aid pathogen and tick-vector surveillance. We showed that the potential geographic range of D. auratus is far wider than the current geographic distribution of this tick, and that regions in Africa, and in North and South America seem to have suitable climates for D. auratus. Interestingly, in Southeast Asia, Borneo and Philippines also have suitable climates for D. auratus, but D. auratus has not been found in these regions yet despite the apparent close proximity of these regions to Mainland Southeast Asia, where D. auratus occurs. We thus hypothesize that the geographic distribution of D. auratus is largely dependent on the movement of wild pigs and whether or not these wild pigs are able to overcome dispersal barriers. We also review the potential pathogens and the diseases that may be associated with D. auratus and provide an updated host index for this tick.

Cervids as Sentinels for Rickettsia spp. in Portugal

Cervids are highly exposed to ticks, however, their role in the life cycle of these rickettsiae has not been fully elucidated. Given the expanding distribution and growing population of deer species in Portugal, coupled with their direct and indirect interactions with humans during hunting, it becomes crucial to explore their role as sentinels and potential reservoirs of Rickettsia. The present investigation aimed to detect and evaluate exposure to Rickettsia in free-living deer from Portugal. Blood samples (n = 77) were collected from hunted game animals (red deer and fallow deer) from different areas throughout Portugal (Idanha-a-Nova, Monte Fidalgo, Montalvão and Arraiolos) and sera were tested by immunofluorescence assay, to detect antibodies. Additionally, blood DNA samples were screened for SFGR by nested-polymerase chain reaction targeting a fragment of the outer membrane protein B (ompB) gene, as well as for Anaplasma and Ehrlichia spp. targeting the 16S rRNA gene. Thirty-five per cent (25 deer and two fallow deer) tested positive (sera with a titer ≥1:64) for IgG antibodies against Rickettsia conorii. No rickettsial DNA was detected by PCR for the ompB gene, and all DNA samples tested negative for Anaplasma and Ehrlichia. As far as we know, this study is the first screening of cervid species in Portugal for Rickettsia antibodies. The findings suggest that these animals serve as useful sentinel indicators for the circulation of rickettsiae, offering a complementary perspective to studies focused on ticks. The increasing numbers of hunted deer in Portugal and the potential zoonotic features of Rickettsia spp. highlight the importance of continued surveillance directed at tick-borne diseases, especially those involving wild animals.

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

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

Italian peninsula as a hybridization zone of Ixodes inopinatus and I. ricinus and the prevalence of tick-borne pathogens in I. inopinatus, I. ricinus, and their hybrids

BACKGROUND

Ixodes inopinatus was described from Spain on the basis of morphology and partial sequencing of 16S ribosomal DNA. However, several studies suggested that morphological differences between I. inopinatus and Ixodes ricinus are minimal and that 16S rDNA lacks the power to distinguish the two species. Furthermore, nuclear and mitochondrial markers indicated evidence of hybridization between I. inopinatus and I. ricinus. In this study, we tested our hypothesis on tick dispersal from North Africa to Southern Europe and determined the prevalence of selected tick-borne pathogens (TBPs) in I. inopinatus, I. ricinus, and their hybrids.

METHODS

Ticks were collected in Italy and Algeria by flagging, identified by sequencing of partial TROSPA and COI genes, and screened for Borrelia burgdorferi s.l., B. miyamotoi, Rickettsia spp., and Anaplasma phagocytophilum by polymerase chain reaction and sequencing of specific markers.

RESULTS

Out of the 380 ticks, in Italy, 92 were I. ricinus, 3 were I. inopinatus, and 136 were hybrids of the two species. All 149 ticks from Algeria were I. inopinatus. Overall, 60% of ticks were positive for at least one TBP. Borrelia burgdorferi s.l. was detected in 19.5% of ticks, and it was significantly more prevalent in Ixodes ticks from Algeria than in ticks from Italy. Prevalence of Rickettsia spotted fever group (SFG) was 51.1%, with significantly greater prevalence in ticks from Algeria than in ticks from Italy. Borrelia miyamotoi and A. phagocytophilum were detected in low prevalence (0.9% and 5.2%, respectively) and only in ticks from Italy.

CONCLUSIONS

This study indicates that I. inopinatus is a dominant species in Algeria, while I. ricinus and hybrids were common in Italy. The higher prevalence of B. burgdorferi s.l. and Rickettsia SFG in I. inopinatus compared with that in I. ricinus might be due to geographical and ecological differences between these two tick species. The role of I. inopinatus in the epidemiology of TBPs needs further investigation in the Mediterranean Basin.

Tissue-specific localization of tick-borne pathogens in ticks collected from camels in Kenya: insights into vector competence

Background

Tick-borne pathogen (TBP) surveillance studies often use whole-tick homogenates when inferring tick-pathogen associations. However, localized TBP infections within tick tissues (saliva, hemolymph, salivary glands, and midgut) can inform pathogen transmission mechanisms and are key to disentangling pathogen detection from vector competence.

Methods

We screened 278 camel blood samples and 504 tick tissue samples derived from 126 camel ticks sampled in two Kenyan counties (Laikipia and Marsabit) for Anaplasma, Ehrlichia, Coxiella, Rickettsia, Theileria, and Babesia by PCR-HRM analysis.

Results

Candidatus Anaplasma camelii infections were common in camels (91%), but absent in all samples from Rhipicephalus pulchellus, Amblyomma gemma, Hyalomma dromedarii, and Hyalomma rufipes ticks. We detected Ehrlichia ruminantium in all tissues of the four tick species, but Rickettsia aeschlimannii was only found in Hy. rufipes (all tissues). Rickettsia africae was highest in Am. gemma (62.5%), mainly in the hemolymph (45%) and less frequently in the midgut (27.5%) and lowest in Rh. pulchellus (29.4%), where midgut and hemolymph detection rates were 17.6% and 11.8%, respectively. Similarly, in Hy. dromedarii, R. africae was mainly detected in the midgut (41.7%) but was absent in the hemolymph. Rickettsia africae was not detected in Hy. rufipes. No Coxiella, Theileria, or Babesia spp. were detected in this study.

Conclusions

The tissue-specific localization of R. africae, found mainly in the hemolymph of Am. gemma, is congruent with the role of this tick species as its transmission vector. Thus, occurrence of TBPs in the hemolymph could serve as a predictor of vector competence of TBP transmission, especially in comparison to detection rates in the midgut, from which they must cross tissue barriers to effectively replicate and disseminate across tick tissues. Further studies should focus on exploring the distribution of TBPs within tick tissues to enhance knowledge of TBP epidemiology and to distinguish competent vectors from dead-end hosts.

Survey of Rickettsia spp. in ticks (Acari: Ixodidae) infesting opossums (Didelphis albiventris) and capybaras (Hydrochoerus hydrochaeris) from an urban park in southeastern Brazil

Ticks are hematophagous arthropods and, during feeding, may transmit pathogens to vertebrate hosts, including humans. This study aimed to investigate the presence of Rickettsia spp. in ticks collected between 2010 and 2013 from free-ranging capybaras (Hydrochoerus hydrochaeris) and opossums (Didelphis albiventris) that inhabit Sabiá Park in Uberlândia, Brazil. Overall, 1,860 ticks were collected: 1,272 (68.4%) from capybaras (487 of the species Amblyomma sculptum, 475 adults and 12 nymphs; 778 Amblyomma dubitatum, 727 adults and 51 nymphs; and seven larva clusters of the genus Amblyomma); and 588 (31.6%) from opossums (21 A. sculptum, one adult and 20 nymphs; 79 A. dubitatum, all nymphs; 15 Ixodes loricatus, 12 adults and three nymphs; 457 Amblyomma sp. larva clusters; 15 Ixodes sp. larva clusters; and one Argasidae larva cluster). Out of 201 DNA samples tested for the presence of Rickettsia spp. DNA using polymerase chain reaction (PCR) 12 showed amplification of a gtlA gene segment that was specific to Rickettsia bellii, a bacterium non-pathogenic to humans. As there has been a report showing serological evidence of infections caused by Rickettsia species of the spotted fever group (SFG) in capybaras and opossums in the park, including Rickettsia rickettsii, the etiological agent of Brazilian spotted fever, and considering the presence of A. sculptum ticks, which are aggressive to humans, as well as these vertebrate hosts, which are amplifiers of R. rickettsii, it is important to monitor the presence of SFG rickettsiae in the Sabiá Park, which is visited daily by thousands of people.

New hard tick (Acari: Ixodidae) reports and detection of Rickettsia in ticks from Sierra Nevada de Santa Marta, Colombia

The Sierra Nevada de Santa Marta (SNSM), located in northern Colombia, is considered a geographical island with high levels of biodiversity and endemism. However, little is known about tick species and their associated microorganisms at the SNSM. In this study we sampled host-seeking ticks in areas of the town of Minca within the SNSM. We collected 47 ticks identified as Amblyomma pacae, Amblyomma longirostre, Amblyomma ovale, Amblyomma mixtum, Haemaphysalis juxtakochi, Ixodes sp. cf. Ixodes affinis and Ixodes sp. Of these ticks, we tested for Rickettsia spp. by amplifying the gltA, SCA1, and 16S rRNA genes via PCR. Rickettsia amblyommatis was detected in one pool of 3 larvae and in a female of A. pacae. Additonally, we isolated Rickettsia sp. belonging to the group of spotted fevers in larvae of A. longirostre. This study reports new findings of six species of ticks and two species of Rickettsia within the SNSM.

Detection of Rickettsia raoultii in Vermipsylla alakurt-Like Fleas of Sheep in Northwestern China

INTRODUCTION

To date, a total of 2574 validated flea species have been discovered. Vermipsyllidae is a family of fleas that comprises at least eight species. Vermipsylla is a genus of the family Vermipsyllidae within the order Siphonaptera of fleas. Here a novel Vermipsylla species was described, and rickettsial agent was also detected in it.

METHODS

A total of 128 fleas were collected directly from 260 pastured sheep in China. Of these, eight representative fleas (four males and four females) were identified by key morphological features. Meanwhile, 120 flea DNAs, including six flea samples for molecular taxonomy, were subjected to Rickettsia spp. DNA detection. The molecular identity of fleas was determined by amplification and sequenmce analysis of four genetic markers (the 28S rDNA genes, the 18S rDNA genes, the mitochondrial cytochrome c oxidase subunit I and subunit II). In addition, five Rickettsia-specific gene fragments were used to identify the species of the rickettsial agents. The amplified products were sequenced and phylogenetically analyzed.

RESULTS

The morphological characteristics of the flea species identified in this study were similar to Vermipsylla alakurt, but presented difference in hair number of the metepimeron, the third tergum, the genitals and the tibiae of hind leg. The 18S rDNA, 28S rDNA and COII genetic markers from fleas showed the highest identity to those of V. alakurt, shared 98.45% (954/969), 95.81% (892/931) and 85.86% (571/665) similarities, respectively. However, the COI sequence showed the highest identity to that of Dorcadia ioffi with 88.48% (576/651) similarity. Rickettsia raoutii tested positive in 14.17% (17/120) flea DNA samples.

CONCLUSION

Our study reports the detection of R. raoultii in V. alakurt-like fleas infesting sheep in China.

Human rickettsial infections in India - A review

Rickettsial infections are emerging and/or re-emerging disease that poses a serious global threat to humans and animals. Transmission to humans and animals is through the bite of the ectoparasites including ticks, fleas and chigger mites. Most of the rickettsial diseases are endemic in India, but underdiagnosed. This review is aimed at analyzing the prevalence of rickettsiosis in India and the advancement of rickettsial diagnosis. We have conducted a systematic review on the prevalence of rickettsial disease in India ranging from 1.3% to 46.6% for spotted fever, 2.4% to 77.8% for scrub typhus and 1% to 46.4% for Q fever, based on the literature published with the evidence of isolation, serological, and molecular diagnostics. Search engines Medline/PubMed, Science Direct, ProQuest, and EBSCO were used to retrieve the articles from electronic databases by using appropriate keywords to track the emergence of these rickettsial diseases in India for the period of 1865 to till date. We retrieved 153 published rickettsial articles on hospital-based studies from India that were purely made on the basis of prevalence and the laboratory parameters viz., Weil-Felix test (WF) and Rapid Immunochromatographic tests (RICT) with reference to the gold standard IFA and ELISA. More epidemiological studies are required for epidemic typhus to know the exact prevalence status of this louse-borne rickettsiosis in India. Currently, there is no confirmed specific inflammatory marker for rickettsial diseases. Moreover, serological cross-reactivity is an important aspect, and it should be investigated in endemic areas, there is also a need to include molecular diagnostic techniques for further confirmation in healthcare settings.

Analyses of Bloodmeal Hosts and Prevalence of Rickettsia parkeri in the Gulf Coast Tick Amblyomma maculatum (Acari: Ixodidae) From a Reconstructed Piedmont Prairie Ecosystem, North Carolina

Host feeding patterns and the prevalence of infection with Rickettsia parkeri were determined for the primary vector, Amblyomma maculatum Koch as well as sympatric tick species A. americanum (Linnaeus) and Dermacentor variabilis (Say) collected from a reconstructed prairie in the Piedmont region of North Carolina during 2011 and 2012. The occurrence of R. parkeri among A. maculatum adults and nymphs was 36.9% (45/122) and 33.3% (2/6), respectively. Rickettsia parkeri was detected in a single male A. americanum 2.3% (1/43). A PCR-reverse line blot hybridization assay of a 12S rDNA fragment amplified from remnant larval and nymphal bloodmeals of host-seeking ticks was used to identify bloodmeal hosts. Of the tick samples tested, bloodmeal host identification was successful for 29.3% (12/41) of adult A. americanum and 39.2% (20/51) of adult D. variabilis. For A. maculatum, bloodmeal host identification was successful for 50% (61/122) of adults collected from vegetation and 100% (4/4) of nymphs removed from cotton rats (Sigmodon hispidus Say and Ord). The cotton rat was the most common bloodmeal host with 59.0% (36/61) identified for adult A. maculatum. No statistically significant association was observed, however, between bloodmeal host and pathogen prevalence for any tick species. While the cotton rat was an important bloodmeal host for A. maculatum nymphs, this vertebrate did not appear to be the primary source of R. parkeri infection for A. maculatum.

Prevalence of tick infestation and molecular characterization of spotted fever Rickettsia massiliae in Rhipicephalus species parasitizing domestic small ruminants in north-central Nigeria

Ticks are of great menace to animal and human health. They serve as vectors to both animals and human pathogens including Rickettsia species. Tick-borne rickettsiosis in West Africa remains incompletely understood. We determined the prevalence of tick infestation among small ruminants and molecularly described a clinically significant spotted fever Rickettsia massiliae from Rhipicephalus ticks collected from North-Central, Nigeria. A total of 352 small ruminants comprising of 152 sheep and 200 goats that were brought for slaughter at the major small ruminant slaughterhouse in Ilorin were examined for the presence of ticks. The collected Rhipicephalus species were subjected to molecular studies to detect and characterize Rickettsia massiliae. Of the small ruminants examined, 21 sheep and 46 goats were infested with ticks representing 13.82% and 23.00% respectively. Eight and nine different species of ticks were detected in sheep and goats respectively, with Rhipicephalus (Boophilus) decoloratus being the most prevalent tick species in both sheep and goats. There was a significant difference (p <0.01) in the prevalence of the different tick species collected in sheep and in goats. Based on the PCR amplification of the 23S-5S intergenic spacer (IGS), only 2 of the 142 Rhipicephalus tick samples screened for R. massiliae were positive (1.41%; 95% CI = 0.39-4.99). Rickettsia massiliae was detected from Rhipicephalus turanicus collected from sheep. Sequences obtained from the PCR carried out by amplifying Rickettsia 23S-5S IGS showed 99-100% close identity with members of the R. massiliae group. This study has for the first time confirmed the presence of spotted fever group Rickettsia massiliae from feeding ticks in Nigerian small ruminants. Further investigations to determine the possible pathogenic role of human R. massiliae infection in Nigeria would be beneficial.

High Prevalence of Rickettsia bellii in Mosquitoes From Eastern China

Mosquitoes are the most important vectors carrying significant numbers of human pathogens. Recent studies implicated that mosquitoes play an important role in circulation and transmission of multiple Rickettsia species. In this study, Rickettsia bellii was identified in four mosquito species (Culex pipiens, C. tritaeniorhynchus, Aedes albopictus, and Anopheles sinensis) collected from three Eastern China provinces during 2019-2020. Rickettsia bellii was detected in 37.50 and 26.32% of the C. pipiens pools from Beijing and Jiangsu province, respectively. In C. tritaeniorhynchus and An. sinensis from Shandong, the infection rate is 20.00 and 6.25%, respectively. Additionally, three Ae. albopictus pools (3/42, 7.14%) from Beijing were also detected positive for R. bellii. Genetic and phylogenetic analysis on 16S, gltA, and groEL genes indicates that sequences from all these strains are highly homologous and closely related to other R. bellii strains. This is the first report that Ae. albopictus and C. tritaeniorhynchus harbor R. bellii. The wide host range and high infection rate in certain areas may dramatically increase the exposure of R. bellii to human and other vertebrates. The role of mosquitoes in transmission of rickettsiosis and its potential risk to public health should be further considered.

Carios kelleyi (Acari: Ixodida: Argasidae) Infected With Rickettsial Agents Documented Infesting Housing in Kansas, United States

During September-December 2018, 25 live ticks were collected on-post at Fort Leavenworth, Kansas, in a home with a history of bat occupancy. Nine ticks were sent to the Army Public Health Center Tick-Borne Disease Laboratory and were identified as Carios kelleyi (Cooley and Kohls, 1941), a species that seldom bites humans but that may search for other sources of blood meals, including humans, when bats are removed from human dwellings. The ticks were tested for numerous agents of human disease. Rickettsia lusitaniae was identified by multilocus sequence typing to be present in two ticks, marking the first detection of this Rickettsia agent in the United States and in this species of tick. Two other Rickettsia spp. were also detected, including an endosymbiont previously associated with C. kelleyi and a possible novel Rickettsia species. The potential roles of C. kelleyi and bats in peridomestic Rickettsia transmission cycles warrant further investigation.

Zoonotic vector-borne bacteria in wild rodents and associated ectoparasites from Tunisia

Wild rodents are considered as potential carriers of several zoonotic vector-borne bacteria but their epidemiology is poorly understood in Tunisia. A total of 305 biological samples (100 spleens, 100 livers, 100 kidneys, and 5 pooled ectoparasites (Xenopsylla cheopis, Laelaps echidninus, Ornithonyssus sp., Hoplopleura sp. and eggs of the rat fleas)) were collected from 100 wild rodents from three Tunisian governorates. Molecular screening was performed to reveal infections with main vector-borne bacteria. Captured rodents belonged to three rodent genera and species including Rattus rattus (n = 51, 51%), Meriones shawi (n = 24, 24%) and Mus musculus (n = 25, 25%). Examined rodents were found to be heavily infested by the rat flea X. cheopis (n = 32, 47%) and the rat mite L. echidninus (n = 22, 32.3%). However, the rat mite Ornithonyssus sp. (n = 13, 19.1%) and the rat lice Hoplopleura sp. (n = 1, 1.5%) were rarely identified. Based on 16S rRNA and msp4 genes, infection with Anaplasmataceae bacteria was detected in six specimens of R. rattus and one M. shawi. Pathogenic A. phagocytophilum (n = 1), A. phagocytophilum-like 1 (Anaplasma sp. Japan) (n = 1), and A. ovis (n = 5) were identified. On the basis of ompB, ompA and gltA genes, infection with Rickettsia spp. was identified in three specimens of R. rattus and one of M. shawi. Five Rickettsia species of the spotted fever group, corresponding to R. monacensis, R. helvetica, R. massiliae, R. africae, and R. aeschlimannii, were detected in mixed infections. Bartonella henselae DNA was also found in two R. rattus, based on rpoB partial sequences. All revealed Anaplasma, Rickettsia and Bartonella bacteria were detected in spleen samples. Ehrlichia, Coxiella and Borrelia spp. were not identified in any of the tested samples. In Tunisia, this is the first report indicating infections with Anaplasma, Rickettsia and Bartonella spp. in wild rodents, particularly present alongside domestic livestock and human. This represents a serious risk of potential bacterial transmission. Thus, controlling rodent population in animal herds, residential areas and sensitizing local people to this risk seem absolutely necessary.

The structure of the cereal leaf beetle (Oulema melanopus) microbiome depends on the insect's developmental stage, host plant, and origin

Cereal leaf beetle (CLB, Oulema melanopus, Coleoptera, Chrysomelidae) is a serious agricultural pest that causes considerable damages to agricultural production. The aim of this study was to characterize the bacterial communities associated with larvae and imagoes of CLB collected from various cereal host species and locations. The bacterial profile was characterized by 16S rRNA gene sequencing at the V3-V4 hypervariable region. Using taxonomy-based analysis, the bacterial community of CLB containing 16 phyla, 26 classes, 49 orders, 78 families, 94 genera, and 63 species of bacteria was identified. The abundance of Wolbachia, Rickettsia, and Lactococcus genus was significantly higher in CLB imagoes than in larvae. Statistical analysis confirmed that the bacterial community of the larvae is more diverse in comparison to imagoes and that insects collected from spring barley and wheat are characterized by a much higher biodiversity level of bacterial genera and species than insects collected from other cereals. Obtained results indicated that the developmental stage, the host plant, and the insect's sampling location affected the CLB's microbiome. Additionally, the CLB core microbiome was determined. It consists of 2 genera (Wolbachia and Rickettsia) shared by at least 90% tested CLB insects, regardless of the variables analysed.

Two parasites in one host: spatiotemporal dynamics and co-occurrence of Microsporidia and Rickettsia in an amphipod host

Biological interactions can greatly influence the abundance of species. This is also true for parasitic species that share the same host. Microsporidia and Rickettsia are widespread intracellular parasites in populations of Paracalliope fluviatilis, the most common freshwater amphipods in New Zealand. Although both parasites coexist in many populations, it is unclear whether they interact with each other. Here, we investigated spatial−temporal dynamics and co-occurrence of the two parasites, Microsporidia and Rickettsia in P. fluviatilis hosts, across one annual cycle and in three different locations. Prevalence of both Microsporidia and Rickettsia changed over time. However, while the prevalence of Rickettsia varied significantly between sampling times, that of Microsporidia did not change significantly and remained relatively low. The two parasites therefore followed different temporal patterns. Also, the prevalence of both parasites differed among locations, though the two species reached their highest prevalence in different locations. Lastly, there was no evidence for positive or negative associations between the two parasite species; the presence of one parasite in an individual host does not appear to influence the probability of infection by the other parasite. Their respective prevalence may follow different patterns among populations on a larger spatial scale due to environmental heterogeneity across locations.

Molecular investigation of tick-borne pathogens in ticks removed from tick-bitten humans in the southwestern region of the Republic of Korea

In this study, we investigated the presence of tick-borne pathogens in ticks removed from tick-bitten humans in the southwestern provinces of the Republic of Korea (ROK). We identified 33 ticks from three tick species, namely Amblyomma testudinarium (60.6%), Haemaphysalis longicornis (27.3%), and Ixodes nipponensis (12.1%) in order of occurrence via morphology and 16S rDNA-targeting polymerase chain reaction (PCR). Tick-borne pathogens were detected in 16 ticks using pathogen-specific PCR. From the results, 12 ticks (36.4%) tested positive for spotted fever group (SFG) Rickettsia: Rickettsia monacensis (1/12), R. tamurae (8/12), and Candidatus Rickettsia jingxinensis (3/12). Three ticks (9.1%) were positive for Anaplasma phagocytophilum. In addition, three ticks (9.1%) tested positive for Babesia gibsoni (1/3) and B. microti (2/3). In conclusion, we identified three tick species; the most common species was A. testudinarium, followed by H. longicornis and I. nipponensis. SFG Rickettsia, A. phagocytophilum, and Babesia spp. were the most frequently detected pathogens in ticks removed from tick-bitten humans. To our knowledge, this is the first report of R. tamurae and Ca. R. jingxinensis detection in Korea. The present results will contribute to the understanding of tick-borne infections in animals and humans in the ROK.

Diversity and genotypic analysis of tick-borne pathogens carried by ticks infesting horses in Korea

Ticks account for an extensive range of health and welfare issues in horses. In addition, tick-borne pathogens (TBPs) limit global animal trading and equine sporting events. Here, we assess the prevalence, co-infectivity and risk factors of TBPs in horse ticks in Korea. A total of 245 hard ticks, including 103 male and 142 female adults, were obtained from horses on Jeju Island during the spring to autumn seasons of 2013-2019. All collected ticks were identified as adult Haemaphysalis longicornis. We screened and analyzed each tick for the presence of several TBPs by polymerase chain reaction (PCR) analysis. Among the 245 ticks, we detected genes for three TBPs, Candidatus Rickettsia longicornii (22.9%), Ehrlichia canis (0.4%) and Theileria luwenshuni (0.4%), while Anaplasma spp. was not detected. TBPs were most prevalent in ticks harvested during the autumn season, and more abundant in the female than male adults. This is the first report of the genera Ehrlichia, Rickettsia and Theileria in horse ticks in Korea. TBPs in horse ticks are likely a reservoir for zoonotic transmission to other animals, including humans. Our findings demonstrate the need for further understanding of the prevalence and epidemiology of TBPs in wild and domestic animals.

Molecular detection and identification of spotted fever group rickettsiae in ticks collected from horses in Cuba

Spotted fever group (SFG) rickettsiae are obligatory intracellular bacteria that cause disease in humans and other animals. Ixodid ticks are the principal vectors of SFG rickettsiae. The present study aimed to determine the prevalence and species identity of SFG rickettsiae in ticks and horses from urban and rural areas of western Cuba using PCR assays. Tick samples, collected from 79 horses, consisted of 14 Amblyomma mixtum adults, 111 Dermacentor nitens adults and 19 pools of D. nitens nymphs (2-5 individuals/pool). The PCR results revealed the presence of Rickettsia spp. in 64% of the A. mixtum adults, 16% of the D. nitens adults, and 11% of the pooled samples of D. nitens nymphs. In contrast, Rickettsia spp. was not detected in any of the 200 horse blood samples included in this study. DNA sequence data of the rickettsial 17 kDa antigen gene showed that Rickettsia amblyommatis was present in A. mixtum; and Rickettsia felis in D. nitens. This is the first report of R. felis in D. nitens in Cuba. The present study extends our knowledge of the potential vector spectrum and distribution of SFG rickettsiae pathogens in western Cuba.

Prevalence and distribution of pathogen infection and permethrin resistance in tropical and temperate populations of Rhipicephalus sanguineus s.l. collected worldwide

The brown dog tick, Rhipicephalus sanguineus sensu lato (s.l.) Latreille (Acari: Ixodidae), is a peridomestic, cosmopolitan parasite of dogs known to vector numerous pathogens of veterinary and medical importance. Recent phylogenetic analyses separate this tick into temperate and tropical lineages. Populations of Rh. sanguineus s.l. have been reported to exhibit sodium channel target site insensitivity to permethrin and etofenprox, which is likely due to the prolonged use of pyrethroids against many pests in and around the home. In this study, populations collected in the Caribbean, Africa, Asia, Europe and North America, were tested to identify the distribution of a known resistance mechanism, pathogen-vector interactions and phylogeny in relation to latitude. Using molecular assays, populations from 29 distinct locations were simultaneously geographically typed and screened for bacterial infection by Rickettsia, Ehrlichia, Babesia and Hepatozoon species, and for the presence of a sodium channel single nucleotide polymorphism known to confer permethrin resistance. Implications of these results on Rh. sanguineus s.l. management in association with geographical distribution will be discussed.

Frequency and factors associated of potential zoonotic pathogens (Borrelia spp., Rickettsia spp., Leishmania spp., and Anaplasma phagocytophilum) in equids in the state of Bahia, Brazil

BACKGROUND

Currently, various zoonotic diseases are classified as emerging or reemerging. Because equids have a direct relationship with various vectors, they are possibly more frequently exposed to zoonotic agents than are humans. The undeniable importance of diseases such as human granulocytic anaplasmosis, spotted fever, and leishmaniasis for both public and animal health, as well as the possibility of equids acting as sources, reservoirs, or even sentinels for these pathogens, justifies the detection of their frequency and factors associated with infection in equids from northeastern Brazil.

METHODS

Blood samples were collected from 569 equids (528 horses, 33 donkeys, and 8 mules), 516 from a rural area and 53 from an urban area. Pathogen detection was carried out as follows: Borrelia spp. and Rickettsia spp., serological analysis; Leishmania spp., serological analysis and polymerase chain reaction (PCR); Anaplasma phagocytophilum, PCR. Determination of associated factors was carried out through generalized linear models.

RESULTS

The frequencies of positivity for the pathogens observed in equids were as follows: Borrelia spp., 13.9% (79/569); Leishmania spp., 3.5% (20/569); Rickettsia spp. 33.4% (190/569). Regarding factors associated with infection, male sex was associated with protection against Borrelia spp.; donkeys and mules were associated with protection against Rickettsia spp., while a younger age was a risk factor. The infection of A. phagocytophilum was not detected in the sampled population. Co-infection was detected in 5.1% (29/569) of the animals.

CONCLUSIONS

Most of the studied pathogenic agents are present in the prospected area, indicating a possible risk for both human and animal health. This demonstrates that equids can be considered important sentinels in the assessment of pathogens with zoonotic potential in the region.

Detection of Rickettsia lusitaniae Among Ornithodoros sawaii Soft Ticks Collected From Japanese Murrelet Seabird Nest Material From Gugul Island, Republic of Korea

In a follow-up to the investigations of soft ticks identified from seabird nest soil and litter collected from coastal islands of the Republic of Korea (ROK), Ornithodoros sawaii and Ornithodoros capensis were assessed for the presence and identification of rickettsiae. Ticks collected from samples of 50-100 g of nest litter and soil from seabird nests were identified individually by morphological techniques, and species confirmed by sequencing of the mt-rrs gene. Subsequently, tick DNA preparations were screened for the presence of rickettsiae using a genus-specific nested PCR (nPCR) assay targeting the 17 kDa antigen gene. The amplicons from the 17 kDa assay and two additional nPCR assays targeting the gltA and ompB gene fragments were sequenced and used to identify the rickettsiae. A total of 134 soft ticks belonging to two species, O. sawaii Kitaoka & Suzuki 1973 (n = 125) and O. capensis Neumann 1901 (n = 9), were collected. Rickettsia lusitaniae DNA was detected and identified among O. sawaii ticks (n = 11, 8.8%) collected from nest litter and soil of the Japanese murrelet (Synthliboramphus wumizusume Temminck 1836) at Gugul Island along the western coastal area of the ROK. This study confirmed for the first time the presence of R. lusitaniae associated with O. sawaii collected from migratory seabird nests in the ROK.

Detection of Novel Spotted Fever Group Rickettsiae (Rickettsiales: Rickettsiaceae) in Ticks (Acari: Ixodidae) in Southwestern China

Spotted fever group rickettsiae, mainly maintained and transmitted by ticks, are important etiological agents of (re)emerging zoonotic diseases worldwide. It is of great significance to investigate spotted fever group rickettsiae in ticks in different areas for the prevention and control of rickettsioses. In this study, a total of 305 ticks were collected from wild and domestic animals in Chongqing, Guizhou, Yunnan, and Guangxi provinces of southwestern China during 2017-2019 and examined for the presence of spotted fever group rickettsiae by PCR with primers targeting the partial gltA, ompA, rrs, and htrA genes. Results showed that two spotted fever group rickettsiae species, including the pathogenic Candidatus Rickettsia jingxinensis (Rickettsiales: Rickettsiaceae) and a potential novel species Rickettsia sp. sw (Rickettsiales: Rickettsiaceae), were identified. The Ca. R. jingxinensis sequences were recovered from Rhipicephalus microplus (Ixodida: Ixodidae) and Haemaphysalis longicornis (Ixodida: Ixodidae) ticks and phylogenetically clustered with previous Ca. R. jingxinensis, Ca. R. longicornii (Rickettsiales: Rickettsiaceae), and Rickettsia sp. XY118 (Rickettsiales: Rickettsiaceae) strains. Rickettsia sp. sw was detected in Amblyomma geoemydae (Ixodida: Ixodidae) and Rh. microplus. Interestingly, as far as we know, this was the first report of Rickettsia (Rickettsiales: Rickettsiaceae) in A. geoemydae. Phylogenetic analyses indicated that this potential novel species was closely related to R. aeschlimannii (Rickettsiales: Rickettsiaceae) with gltA and ompA genes and grouped in a cluster composed of R. montanensis (Rickettsiales: Rickettsiaceae), R. raoultii (Rickettsiales: Rickettsiaceae), R. aeschlimannii, R. massiliae (Rickettsiales: Rickettsiaceae), and R. rhipicephali (Rickettsiales: Rickettsiaceae) with htrA, while formed a separate clade with rrs. The pathogenicity of Rickettsia sp. sw should be further confirmed. These results expand the knowledge of the geographical distribution and vector distribution of spotted fever group rickettsiae in China and are useful for assessing the potential public health risk.

Established Population of the Gulf Coast Tick, Amblyomma maculatum (Acari: Ixodidae), Infected with Rickettsia parkeri (Rickettsiales: Rickettsiaceae), in Connecticut

We identified an established population of the Gulf Coast tick (Amblyomma maculatum Koch) infected with Rickettsia parkeri in Connecticut, representing the northernmost range limit of this medically relevant tick species. Our finding highlights the importance of tick surveillance and public health challenges posed by geographic expansion of tick vectors and their pathogens.

Abundance of Ticks (Acari: Ixodidae) and Presence of Rickettsia and Anaplasma in Ticks Infesting Domestic Animals From Northern India

Rickettsia and Anaplasma are bacteria that can be transmitted by hematophagous arthropods such as ticks infesting animals in close proximity to humans. The main objective of the present study was to investigate abundance of common tick species infesting domestic animals and presence of Rickettsia and Anaplasma in tick populations. Adult ticks were collected from domestic animals in rural areas and screened by molecular detection of bacterial DNA for these two genera of bacteria. A total of 1,778 adult ixodid tick specimens were collected from 200 cattle, 200 buffaloes, 200 goats, and 40 dogs. The collection consisted of four species of ixodid ticks, Rhipicephalus (Boophilus) microplus (Canestrini) (83.8%), Hyalomma kumari (Sharif) (7.1%), Rhipicephalus sanguineus (Latreille) (6.4%), and Dermacentor auratus (Supino) (2.7%) infesting the domestic animals. The prevalence of all the collected tick species was highest in the month of October. Anaplasma spp. was the most frequently identified bacteria (3.3%) in tested ticks. Of 17 positive tick pools for Anaplasma spp., 14 pools were from ticks infesting cattle, 2 pools of ticks collected from buffalo, and the remaining pool were ticks infesting a goat at the time of collection. Although 1.6% tick pools of R. microplus collected from cattle tested positive for Rickettsia spp., present investigation provides evidence of the most prevalent ixodid ticks infesting domestic animals and the presence of obligate intracellular bacteria, Rickettsia and Anaplasma, in these ticks collected in the Gorakhpur division of Northern India.

Win by Quantity: a Striking Rickettsia-Bias Symbiont Community Revealed by Seasonal Tracking in the Whitefly Bemisia tabaci

Maintaining an adaptive seasonality is a basic ecological requisite for cold-blooded organism insects which usually harbor various symbionts. However, how coexisting symbionts coordinate in insects during seasonal progress is still unknown. The whitefly Bemisia tabaci in China harbors the obligate symbiont Portiera that infects each individual, as well as various facultative symbionts. In this study, we investigated whitefly populations in cucumber and cotton fields from May to December 2019, aiming to reveal the fluctuations of symbiont infection frequencies, symbiont coordination in multiple infected individuals, and host plants effects on symbiont infections. The results indicated that the facultative symbionts Hamiltonella (H), Rickettsia (R), and Cardinium (C) exist in field whiteflies, with single (H) and double (HC and HR) infections occurring frequently. Infection frequencies of Hamiltonella (always 100%) and Cardinium (29.50-34.38%) remained steady during seasonal progression. Rickettsia infection frequency in the cucumber whitefly population decreased from 64.47% in summer to 35.29% in winter. Significantly lower Rickettsia infection frequency (15.55%) was identified in cotton whitefly populations and was not subject to seasonal fluctuation. Nevertheless, Rickettsia had a significantly quantitative advantage in the symbiont community of whitefly individuals and populations from both cucumber and cotton field all through the seasons. Moreover, higher Portiera and Hamiltonella densities were found in HC and HR whitefly than in H whitefly, suggesting these symbionts may contribute to producing nutrients for their symbiont partners. These results provide ample cues to further explore the interactions between coexisting symbionts, the coevolutionary relationship between symbionts and host symbiont-induced effects on host plant use.

Rickettsial agents detected in the genus Psathyromyia (Diptera:Phlebotominae) from a Biosphere Reserve of Veracruz, Mexico

Phlebotomine sand flies are considered the main vectors of Leishmania, the causal agents of leishmaniasis, which is a serious emerging public health problem worldwide. The use of biological control alternatives, like endosymbiotic bacteria (Wolbachia and Rickettsia), have been proposed to decrease sand fly populations and reduce Leishmania transmissions, yet only few records on the detection of Wolbachia or Rickettsia in sand flies are available worldwide. The aim of this study was to perform the molecular detection of Rickettsial agents associated with sand flies from the last patch of a rainforest in south-eastern Mexico, where a high prevalence of Leishmania infantum has been reported. Sampling effort of sand flies covered 300 trap-nights between 2011 and 2013, and a total of 925 specimens from twelve species were morphologically identified. Using PCR techniques, we identified a new lineage of the endosymbionts Rickettsia in Psathyromyia aclydifera (prevalence of 19.54%), and Wolbachia in Psathyromyia shannoni and Lutzomyia sp. (prevalence of 25%). The detected Wolbachia lineage was similar to the wWhi strain found in Pa. shannoni from Colombia and Nyssomyia whitmani from Brazil; whereas the identified Rickettsia represents a new lineage worldwide. This is the first record of Rickettsial agents associated to sand flies from this region, yet it remains for analysed if these bacteria possibly play a role as vector control agents, capable of reducing the sand fly populations in Mexico.

Rickettsia parkeri and Candidatus Rickettsia andeanae in Amblyomma maculatum Group Ticks

We determined prevalence of Rickettsia spp. in 172 ticks of the Amblyomma maculatum group collected from 16 urban sites in Oklahoma City, Oklahoma, USA, during 2017 and 2018. Most ticks (59.3%) were collected from 1 site; 4 (2.3%) were infected with Rickettsia parkeri and 118 (68.6%) with Candidatus Rickettsia andeanae.

Molecular detection of Candidatus Rickettsia asembonensis in fleas collected from pets and domestic animals in Puducherry, India

Rickettsia are obligate intracellular pathogens transmitted by arthropod vectors. The re-emergence of several rickettsioses imposes severe global health burden. In addition to the well-established rickettsial pathogens, newer rickettsial species and their pathogenic potentials are being uncovered. There are many reports of spotted and typhus fever caused by rickettsiae in India. Hence, in this study we screened the ectoparasites of pet and domestic animals for the presence of rickettsia using polymerase chain reaction. Nine cat flea samples (Ctenocephalides felis felis), that tested positive for the presence of rickettsia were subjected to Multi Locus Sequence Typing. Nucleotide sequencing and Phylogenetic analysis of gltA, ompB and 16rrs genes revealed that the rickettsiae detected in cat fleas was Rickettsia asembonensis. Further studies are required to assess Rickettsia asembonensis pathogenic potential to human and its enzootic maintenance of in various hosts and vectors.

Behavioral characteristics and endosymbionts of two potential tularemia and Rocky Mountain spotted fever tick vectors

Due to climate change-induced alterations of temperature and humidity, the distribution of pathogen-carrying organisms such as ticks may shift. Tick survival is often limited by environmental factors such as dryness, but a predicted hotter and wetter world may allow the expansion of tick ranges. Dermacentor andersoni and D. variabilis ticks are morphologically similar, co-occur throughout the Inland Northwest of Washington State, U.S.A., and both can be injected with pathogenic Rickettsia and Francisella bacteria. Differences in behavior and the potential role of endosymbiotic Rickettsia and Francisella in these ticks are poorly studied. We wanted to measure behavioral and ecological differences between the two species and determine which, if any, Rickettsia and Francisella bacteria - pathogenic or endosymbiotic - they carried. Additionally, we wanted to determine if either tick species may be selected for if the climate in eastern Washington becomes wetter or dryer. We found that D. andersoni is more resistant to desiccation, but both species share similar questing behaviors such as climbing and attraction to bright light. Both also avoid the odor of eucalyptus and DEET but not permethrin. Although both tick species are capable of transmitting pathogenic species of Francisella and Rickettsia, which cause tularemia and Rocky Mountain Spotted Fever, respectively, we found primarily non-pathogenic endosymbiotic strains of Francisella and Rickettsia, and only one tick infected with F. tularensis subspecies holarctica.

Detection of Bartonella sp. and a novel spotted fever group Rickettsia sp. in Neotropical fleas of wild rodents (Cricetidae) from Southern Brazil

The Neotropical region shows a great diversity of fleas, comprising more than 50 genera. The importance of the study of fleas is linked to their potential role as disease vectors. The aim of this study is to investigate the presence of Rickettsia spp. and Bartonella spp. in Neotropical fleas collected from wild rodents in Southern Brazil. From 350 rodents captured, 30 were parasitized by fleas. A total of 61 fleas belonging to two genera and six different species were collected (Craneopsylla minerva minerva, Polygenis occidentalis occidentalis, Polygenis platensis, Polygenis pradoi, Polygenis rimatus, and Polygenis roberti roberti). In 13 % of fleas of three different species (C. minerva, P. platensis, and P. pradoi) Rickettsia sp. DNA was found. Phylogenetic analysis of concatenated sequences of gltA, htrA, and ompA genes showed that Rickettsia sp. found in rodent fleas (referred as strain Taim) grouped together with Spotted Fever Group Rickettsia. In reference to Bartonella spp., five genotypes were identified in seven fleas of two species (C. minerva and P. platensis) and in five rodent spleens. Also, 207 frozen samples of wild rodents were screened for these pathogens: while none was positive for Rickettsia spp.; five rodent spleens were PCR-positive for Bartonella spp.. Herein, we show the detection of potential novel variants of Bartonella sp. and Rickettsia sp. in fleas collected of wild rodents from Southern Brazil. Further studies are needed to fully characterize these microorganisms, as well as to improve the knowledge on the potential role of Neotropical flea species as diseases vectors.

Distribution and Occurrence of Amblyomma maculatum sensu lato (Acari: Ixodidae) and Rickettsia parkeri (Rickettsiales: Rickettsiaceae), Arizona and New Mexico, 2017-2019

Amblyomma maculatum Koch sensu lato (s.l.) ticks are the vector of Rickettsia parkeri in Arizona, where nine cases of R. parkeri rickettsiosis have been identified since the initial case in 2014. The current study sought to better define the geographic ranges of the vector and pathogen and to assess the potential public health risk posed by R. parkeri in this region of the southwestern United States. A total of 275 A. maculatum s.l. ticks were collected from 34 locations in four counties in Arizona and one county in New Mexico and screened for DNA of Rickettsia species. Rickettsia parkeri was detected in 20.4% of the ticks, including one specimen collected from New Mexico, the first report of R. parkeri in A. maculatum s.l. from this state. This work demonstrates a broader distribution of A. maculatum s.l. ticks and R. parkeri in the southwestern United States than appreciated previously to suggest that R. parkeri rickettsiosis is underrecognized in this region.

Survey of Rickettsia parkeri and Amblyomma maculatum associated with small mammals in southeastern Virginia

Small mammals are often parasitized by the immature stages of hard-bodied ticks (family Ixodidae) and may serve as reservoir hosts of tick-borne pathogens. Amblyomma maculatum, the Gulf Coast tick, is the primary vector of Rickettsia parkeri, the causative agent of R. parkeri rickettsiosis. This hard-bodied tick species is expanding its historical range from the Gulf Coast of the U.S. up the Mid-Atlantic coast. In Mid-Atlantic states, such as Virginia, R. parkeri prevalence is higher in these ticks than those found in its historical range. This high prevalence may be explained in part by small mammal populations. In this study, small mammals were trapped and checked for the presence of immature A. maculatum. The ticks as well as tissue samples from these mammals were tested for the presence of R. parkeri. This study found six rodent species acting as hosts to immature A. maculatum and three species that may play a role in the enzootic cycle of R. parkeri in Virginia.

Rickettsia parkeri (Rickettsiales: Rickettsiaceae) detected in Amblyomma maculatum ticks collected on dogs in Tabasco, Mexico

The present study was carried out to identify Rickettsia species with zoonotic potential in ticks collected from dogs in a rural area in Tabasco, Mexico. In total 197 Amblyomma maculatum ticks were collected from 40 domestic dogs. The collected specimens were pooled and subjected to DNA extraction. A fragment (380 bp) of citrate synthase gene (gltA) was amplified by polymerase chain reaction (PCR) using universal primers for Rickettsia. A second PCR was later performed to amplify a fragment (420 bp) of the outer membrane protein B gene (ompB). The PCR products were purified, sequenced and compared using the basic local alignment search tool (BLAST). Twenty out of 40 (50%) tick pools assayed were positive for rickettsial DNA using both primer pairs. The consensus sequence obtained from the ompB gene fragments showed 99.5-100% of identity with strains of Rickettsia parkeri. This study provides the first molecular evidence of the presence of R. parkeri in A. maculatum ticks infesting domestic dogs from southeastern Mexico. Close contact between dogs and humans should lead to consider the infection caused by this species of Rickettsia among the differential diagnoses for people of Tabasco, Mexico, who show acute febrile syndrome associated to inoculation eschar and have a clinical history of tick exposure.

Molecular detection of rickettsial bacteria in ticks of the genus Ixodes from the Southern Cone of America

To obtain information about rickettsial bacteria in ticks of the genus Ixodes from Argentina and Uruguay, specimens of I. fuscipes (previously named as I. aragaoi), Ixodes pararicinus, Ixodes sp. cf. I. affinis, and Ixodes sp. were tested targeting the rickettsial gltA and ompA genes. Rickettsial bacteria was detected in all of these species. Rickettsia found in Ixodes sp. is closely related to Ca. Rickettsia mendelii, which was previously detected in I. ricinus of the Czech Republic and later in I. brunneus from the USA. Phylogenetic analyses of the Rickettsia strains found in I. fuscipes, I. pararicinus, and Ixodes sp. cf. I. affinis showed that these strains form a clade together with R. buchneri detected in I. scapularis from the USA, which is closely related to R. monacensis from Europe. Rickettsia buchneri, R. cooleyi and the Rickettsia detected in I. fuscipes, I. pararicinus, and Ixodes sp. cf. I. affinis clustered together in a clade well supported, which suggest that they are different strains of R. buchneri. The phylogenetic analysis shows that Ixodes ticks that are closely related in evolutionary terms (i.e. Ixodes species from the I. ricinus complex, I. brunneus-Ixodes sp.) share closely related rickettsial strains. The results of this study show that rickettsial bacteria are present in Ixodes ticks from Argentina and describe the first detection of Ca. R. mendelii in South America.

Rickettsia spp. in Five Tick Species Collected in Central California

Tick-borne disease surveillance in North America has long focused on Lyme disease, though there is currently a significant shift towards comprehensive pathogen surveillance in ticks. Central California has often been overlooked in regular tick-borne pathogen surveillance despite the presence of numerous medically important tick species. The bacterial genus Rickettsia contains tick-borne species that are known pathogens, such as those in the spotted fever group; nonpathogenic endosymbionts; and many species with unknown pathogenic potential. Five common tick species (Ixodes pacificus Cooley and Kohls [Acari: Ixodidae], Dermacentor occidentalis Marx [Acari: Ixodidae], D. variabilis Say, Rhipicephalus sanguineus Latreille [Acari: Ixodidae], and Ornithodoros parkeri Cooley [Acari: Argasidae]) of California were collected by both traditional and modern techniques, and subsequently screened for Rickettsia spp. Many individuals from all five tick species were PCR positive for Rickettsia spp., and a combination of species-specific primers, a restriction fragment length polymorphism assay, and DNA sequencing was used to further characterize the species composition in these ticks. Probable Rickettsia philipii (Rickettsia 364D) was detected in one (1.56%) D. occidentalis collected in Fresno County; R. rhipicephali was detected in 23.4% of D. occidentalis from Fresno Co.; R. bellii was detected in 88.2% of D. variabilis, 7.8% of D. occidentalis, and in one R. rhipicephalus (1.1%) from Fresno Co.; R. monacensis str. Humboldt was detected in three (100%) of I. pacificus collected in both Fresno and Madera Co.; and an uncharacterized Rickettsia was detected in (26.4%) of O. parkeri collected in both Fresno and Madera Co. The findings in this study highlight the need for ongoing surveillance in this region of California.

Rickettsia parkeri (Rickettsiales: Rickettsiaceae) in the Sky Islands of West Texas

Rickettsia parkeri, a tick-borne pathogen distributed throughout several countries of the Americas, causes a mild to moderately severe, eschar-associated spotted fever rickettsiosis. Although most U.S. cases of R. parkeri rickettsiosis are reported from southeastern states, some have been reported recently from remote regions of southern Arizona. These cases are linked to R. parkeri-infected ticks of the Amblyomma maculatum (Acari: Ixodidae) group found in several isolated mountain ranges of southern Arizona and New Mexico, referred to as 'sky islands'. Archival records also document ticks of the A. maculatum group collected from domestic and wild animals in West Texas. We surveyed sites in two sky island chains of Jeff Davis and Brewster counties to document the off-host occurrence of these ticks and identify the presence of R. parkeri in the Trans-Pecos region of Texas. During August 2019, 43 adult A. maculatum group ticks were flagged from vegetation or removed from a road-killed, female mule deer. Of 39 samples evaluated by PCR, eight contained a partial sca0 sequence with complete identity to R. parkeri and two with complete identity to 'Candidatus Rickettsia andeanae', a species of undetermined pathogenicity. Four isolates of R. parkeri were obtained using cell culture. Persons at risk for R. parkeri rickettsiosis include those who work or recreate in these mountains, such as hikers, backpackers, research scientists, foresters, and border enforcement personnel. Additional investigations are needed to define the distribution of these medically important arthropods in other parts of the southwestern United States and northern Mexico.

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.

Rickettsia parkeri in the Pampa biome of southern Brazil: Isolation, molecular characterization, and serological evidence of canine infection

In this work we performed a field study in a spotted fever-endemic area of the Pampa biome in Rio Grande do Sul, the southernmost state of Brazil (Rosário do Sul municipality), with the aim to evaluate the serological status of dogs for spotted fever group (SFG) rickettsiae, to attempt the isolation rickettsiae from A. tigrinum ticks, and to further perform a multi-genic molecular characterization of the rickettsial isolate. For this purpose, we collected blood serum samples and ticks from 18 rural dogs during 2016-2017. By immunofluorescence assay, all 18 dogs (100%) reacted serologically to SFG rickettsiae, with highest endpoint titers to R. parkeri, suggesting that at least part of these dogs have been infected by R. parkeri. Among 23 ticks collected from the dogs (13 A. tigrinum and 10 Rhipicephalus sanguineus sensu stricto), 46% (6/13) A. tigrinum contained DNA of R. parkeri, which was successfully isolated in Vero cell culture from one of these ticks. Partial sequences of five genes (gltA, ompA, virB4, dnaA, dnaK) and 3 intergenic spacers (mppA-purC, rrl-rrf-ITS, rpmE-tRNA^fMet) were generated from this rickettsial isolate, and were all 100% identical to corresponding sequences of R. parkeri s.s. We provide the first report of a viable isolate of R. parkeri from A. tigrinum, confirming that this isolate belongs to the strain R. parkeri s.s., as it has already been demonstrated for other two tick species of the Amblyomma maculatum species complex (A. maculatum and Amblyomma triste).

Molecular detection of Rickettsia species and host associations of Laelaps mites (Acari: Laelapidae) in Taiwan

Various rickettsiae have recently been detected in Laelaps mites (Acari: Laelapidae), which are common ectoparasites of rodents; however, investigations on this topic remain very scarce, particularly in Asia. In the present study, shrews and rodents were trapped from 2006 to 2010 in eight lowland regions of Taiwan (< 500 m in elevation) to collect associated Laelaps mites, from which Rickettsia-a group of emerging pathogens-were detected and identified by assaying the gltA and ompB genes. A total of 853 Laelaps mites of at least four species were collected from a sample of 1004 small mammals that included one shrew and 10 rodent species. Rattus losea was the most common species (44.9% of total hosts) and hosted the highest percentage of mites (76.6% of total mites). Laelaps nuttalli was the most abundant mite species (51.7% of total mites), followed by Laelaps echidninus (24.2%), Laelaps sedlaceki (23.1%), and Laelaps myonyssognathus (0.2%). Notably, Rickettsia species with the highest similarity to spotted fever group (SFG) rickettsiae were identified from seven of the 72 pools of Laelaps mites. The presence of SFG rickettsiae in hematophagous Laelaps mites, particularly including species that are closely associated with commensal rodents in frequent contact with humans, calls for further investigation on the competence of Laelaps mites in transmitting rickettsiae.

Detection of Rickettsia asembonensis in Fleas (Siphonaptera: Pulicidae, Ceratophyllidae) Collected in Five Counties in Georgia, United States

We conducted a molecular survey of Rickettsia in fleas collected from opossums, road-killed and live-trapped in peridomestic and rural settings, state parks, and from pet cats and dogs in Georgia, United States during 1992-2014. The cat flea, Ctenocephalides felis (Bouché) was the predominant species collected from cats and among the archival specimens from opossums found in peridomestic settings. Polygenis gwyni (Fox) was more prevalent on opossums and a single cotton rat trapped in sylvatic settings. Trapped animals were infested infrequently with the squirrel flea, Orchopeas howardi (Baker) and C. felis. TaqMan assays targeting the BioB gene of Rickettsia felis and the OmpB gene of Rickettsia typhi were used to test 291 flea DNAs for Rickettsia. A subset of 53 C. felis collected from a cat in 2011 was tested in 18 pools which were all bioB TaqMan positive (34% minimum infection prevalence). Of 238 fleas tested individually, 140 (58.8%, 95% confidence interval [CI]: 52.5-64.9%) DNAs were bioB positive. Detection of bioB was more prevalent in individual C. felis (91%) compared to P. gwyni (13.4%). Twenty-one (7.2%) were ompB TaqMan positive, including 18 C. felis (9.5%) and 3 P. gwyni (3.2%). Most of these fleas were also positive with bioB TaqMan; however, sequencing of gltA amplicons detected only DNA of Rickettsia asembonensis. Furthermore, only the R. asembonensis genotype was identified based on NlaIV restriction analysis of a larger ompB fragment. These findings contribute to understanding the diversity of Rickettsia associated with fleas in Georgia and emphasize the need for development of more specific molecular tools for detection and field research on rickettsial pathogens.

Tick-borne pathogens in dogs, wild small mammals and their ectoparasites in the semi-arid Caatinga biome, northeastern Brazil

Caatinga is a biome exclusive to the semiarid zone of Brazil, where studies on ticks and tick-borne diseases are scarce. Herein, we investigated the occurrence of Rickettsia, Ehrlichia, and Coxiella in wild mammals, domestic dogs and their ectoparasites using molecular and serological techniques. During 2014-2016, blood samples and ectoparasites were collected from 70 small mammals (51 rodents, 18 marsupials, 1 wild canid) and 147 domestic dogs in three areas of the Caatinga. Through serological analyses of domestic dogs of the three areas, 8 to 11 % were seropositive for Rickettsia rickettsii, 9 to 37 % for Rickettsia amblyommatis, 61 to 75 % for Ehrlichia canis, and 0-5% for Coxiella burnetii. All wild mammals were seronegative for Rickettsia spp. and C. burnetii, except for one rodent (Wiedomys pyrrhorhinos) and one marsupial (Didelphis albiventris) that were seroreactive to C. burnetii, one wild canid (Cerdocyon thous) for R. amblyommatis, and two Rattus rattus for Rickettsia spp. Through PCR targeting DNA of Rickettsia, Ehrlichia or Coxiella, all blood samples were negative, except for the presence of Ehrlichia canis DNA in 8.8 % of the domestic dogs, and a recently reported novel agent, Ehrlichia sp. strain Natal, in one marsupial (Gracilinanus agilis). A total of 222 ticks, 84 fleas, and six lice were collected. Ticks were mostly Rhipicephalus sanguineus sensu lato, some Ixodes loricatus, Ornithodoros rietcorreai, Haemaphysalis sp., and Amblyomma spp.; fleas were Ctenocephalides felis felis, Pulex sp. and Polygenis (Polygenis) bohlsi jordani; and lice were Polyplax sp. and Gyropus sp. Through molecular detection of microorganisms, 9% of C. felis felis contained Rickettsia felis, 20 % of A. auricularium contained R. amblyommatis and 13 % of A. parvum contained 'Candidatus Rickettsia andeanae', whereas Ehrlichia canis DNA was detected in at least 6% of the R. sanguineus s.l. from one area. We report a variety of ectoparasites infesting small mammals and domestic dogs in the Caatinga biome, where these ectoparasites probably act as vectors of rickettsiae, ehrlichial agents (E. canis and Ehrlichia sp. strain Natal) and C. burnetii. Our results highlight to the potential risks of human infection by these tick-borne agents in the Caatinga biome.

Factors affecting the microbiome of Ixodes scapularis and Amblyomma americanum

The microbial community composition of disease vectors can impact pathogen establishment and transmission as well as on vector behavior and fitness. While data on vector microbiota are accumulating quickly, determinants of the variation in disease vector microbial communities are incompletely understood. We explored the microbiome of two human-biting tick species abundant in eastern North America (Amblyomma americanum and Ixodes scapularis) to identify the relative contribution of tick species, tick life stage, tick sex, environmental context and vertical transmission to the richness, diversity, and species composition of the tick microbiome. We sampled 89 adult and nymphal Ixodes scapularis (N = 49) and Amblyomma americanum (N = 40) from two field sites and characterized the microbiome of each individual using the v3-v4 hypervariable region of the 16S rRNA gene. We identified significant variation in microbial community composition due to tick species and life stage with lesser impact of sampling site. Compared to unfed nymphs and males, the microbiome of engorged adult female I. scapularis, as well as the egg masses they produced, were low in bacterial richness and diversity and were dominated by Rickettsia, suggesting strong vertical transmission of this genus. Likewise, microbiota of A. americanum nymphs and males were more diverse than those of adult females. Among bacteria of public health importance, we detected several different Rickettsia sequence types, several of which were distinct from known species. Borrelia was relatively common in I. scapularis but did not show the same level of sequence variation as Rickettsia. Several bacterial genera were significantly over-represented in Borrelia-infected I. scapularis, suggesting a potential interaction of facilitative relationship between these taxa; no OTUs were under-represented in Borrelia-infected ticks. The systematic sampling we conducted for this study allowed us to partition the variation in tick microbial composition as a function of tick- and environmentally-related factors. Upon more complete understanding of the forces that shape the tick microbiome it will be possible to design targeted experimental studies to test the impacts of individual taxa and suites of microbes on vector-borne pathogen transmission and on vector biology.

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.

Surveillance for Amblyomma maculatum (Acari: Ixodidae) and Rickettsia parkeri (Rickettsiales: Rickettsiaceae) in the State of Delaware, and Their Public Health Implications

Amblyomma maculatum Koch is the primary vector of Rickettsia parkeri, the etiologic agent of tidewater spotted fever, and can also carry and transmit a variety of other pathogens. This tick historically has been a costly nuisance to livestock owners in the southeastern United States. Over the past 6 yr, A. maculatum has been collected in numbers sufficient to demonstrate their establishment in Kent County, Delaware, and the presence of R. parkeri has been documented. Our goals were to determine the geographic distribution of A. maculatum and R. parkeri in Delaware, and to equate this to relative risk to the public of encountering R. parkeri-infected ticks. We surveyed for ticks in four locations throughout the state from May to August 2019, and found established A. maculatum populations in all three counties. Laboratory analysis of collected specimens by quantitative polymerase chain reaction detected R. parkeri in A. maculatum populations across the state. These results indicate that A. maculatum could present a health risk to inhabitants of the state, and they also historically have posed a risk to the livestock industry, making them an important consideration in the development and implementation of continued tick surveillance efforts and future policies regarding tick management.

Rickettsia spp. Infecting Lone Star Ticks (Amblyomma americanum) (Acari: Ixodidae) in Monmouth County, New Jersey

Tick-borne rickettsiae are undergoing epidemiological changes in the eastern United States while human encounters with lone star ticks (Amblyomma americanum L.) have increased substantially. We used real-time polymerase chain reaction assays to test for three species of spotted fever group rickettsiae (SFGR) (Rickettsiales: Rickettsiaceae) in 1,858 nymphal A. americanum collected from Monmouth County, New Jersey, a coastal county with endemic Lyme disease and established tick surveillance. Out of the 1,858 tested, 465 (25.0%) were infected with Rickettsia amblyommatis Karpathy, a species of undetermined pathogenicity found frequently in A. americanum, while 1/1,858 (0.05%) contained Rickettsia rickettsii Brumpt, the agent of Rocky Mountain spotted fever. No ticks tested positive for mildly pathogenic Rickettsia parkeri Lackman, and no ticks were co-infected with multiple Rickettsia spp. Our results indicate that A. americanum could be involved in transmission of R. rickettsii to humans in New Jersey, albeit rarely. The much higher rates of R. amblyommatis infection are consistent with hypotheses that human sera reacting to this species could contribute to reports of mild SFGR cases.

Tick-borne pathogens in Ixodes ricinus ticks collected from migratory birds in southern Norway

Birds are important hosts for the first life stages of the Ixodes ricinus tick and they can transport their parasites over long distances. The aim of this study was to investigate the prevalence of Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, Neoehrlichia mikurensis and Rickettsia helvetica in ticks collected from migratory birds in Norway. A total of 815 Ixodes ricinus ticks from 216 birds trapped at Lista Bird Observatory in southern Norway during spring and autumn migration in 2008 were analysed by real-time PCR. B. burgdorferi s. l. was the most prevalent pathogen, detected in 6.1% of the ticks. The prevalence of N. mikurensis, A. phagocytophilum and R. helvetica was 1.2%, 0.9% and 0.4% respectively. In addition, one sample (0.1%) was positive for B. miyamotoi. In total, 8.2% of the ticks were infected with at least one pathogen. Co-infection with B. burgdorferi s. l. and N. mikurensis or A. phagocytophilum was found in 6.0% of the infected ticks. Our results show that all the known major tick-borne bacterial pathogens in Norway are subject to transport by migratory birds, potentially allowing spread to new areas. Our study showed a surprisingly high number of samples with PCR inhibition (57%). These samples had been extracted using standard methodology (phenol-chloroform extraction). This illustrates the need for inhibition controls to determine true prevalence rates.

COYOTES (CANIS LATRANS) IN ARIZONA, USA, EXHIBIT IMMUNE AND GENETIC EVIDENCE OF RICKETTSIAL INFECTIONS

Rocky Mountain spotted fever (RMSF), caused by the bacterium Rickettsia rickettsii, was recognized as endemic in Arizona, US after a 2002 outbreak and has since been a public health concern. The brown dog tick (Rhipicephalus sanguineus sensu lato) is the principal vector of this pathogen in Arizona. Domesticated dogs (Canis lupus familiaris) are the tick's main host, so free-roaming dogs in peridomestic areas have been named the primary risk factor for human cases of RMSF. However, the sudden emergence and long-distance dispersal of the pathogen have not been adequately explained, and one possible mechanism could include wildlife. Coyotes (Canis latrans) are wide ranging in Arizona and closely related to dogs, so it is possible that brown dog ticks parasitize coyotes and infect them. Although R. rickettsii is the most severe spotted fever group (SFG) rickettsial pathogen in humans, others occur in Arizona, and antibodies raised against them are cross-reactive, so we more-broadly hypothesized that coyotes in Arizona are exposed to SFG rickettsiae. We collected coyote tissues in spring 2016 and 2017. We tested sera for antibodies to R. rickettsii and found 9% (8/94) of samples were antibody-positive with titers of ≥256. Subsequent quantitative PCR analyses of skin showed evidence for Rickettsia spp. in 2.9% (4/138) of samples. These data suggest that coyotes have a role in the maintenance of SFG rickettsiae in Arizona. Further investigation is warranted to reveal which specific pathogen-vector complexes act on coyotes in the region and whether they represent a risk to human health.

Molecular evidence of the spotted fever group Rickettsiae in ticks from Yunnan Province, Southwest China

Ixodid ticks transmit many obligate intracellular Rickettsial species. Several previous studies have identified Rickettsia species in the northeastern and southern part of China, but few reports on the prevalence of infection of spotted fever group Rickettsiae (SFGR) in ticks in southwest China are available. Here, we investigated SFGR in 394 adult ticks of five species including Dermacentor nuttalli, Dermacentor silvarum, Haemaphysalis longicornis, Ixodes sinensis and Ixodes persulcatus, collected in the border region between China and Burma in Yunnan Province. PCR was used to detect the presence of the citrate synthase (gltA) gene of Rickettsia species. SFGR was found in 12.1% (15/124) of I. persulcatus ticks, which was significantly higher than the 7.2% (7/97) positive D. nuttalli, 5.4% (3/56) D. silvarum, 5.6% (4/72) H. longicornis and 4.4 (2/45) I. sinensis. A portion of the gltA and ompA gene data subjected to phylogenetic analysis revealed that the detected SFGR clustered into two species, Rickettsia raoultii and the new Rickettsia species Candidatus Rickettsia jingxinensis. Detection of both Rickettsia spp. in this region indicates a potential public health threat posed by SFGR infection in Yunnan Province.