Prevalence of tick-borne bacterial pathogens in Germany-has the situation changed after a decade?

Introduction: Tick-borne pathogens, such as Borreliella spp., Rickettsia spp., and Anaplasma spp., are frequently detected in Germany. They circulate between animals and tick vectors and can cause mild to severe diseases in humans. Knowledge about distribution and prevalence of these pathogens over time is important for risk assessment of human and animal health. Methods: Ixodes ricinus nymphs were collected at different locations in 2009/2010 and 2019 in Germany and analyzed for tick-borne pathogens by real-time PCR and sequencing. Results: Borreliella spp. were detected with a prevalence of 11.96% in 2009/2010 and 13.10% in 2019 with B. afzelii and B. garinii as dominant species. Borrelia miyamotoi was detected in seven ticks and in coinfection with B. afzelii or B. garinii. Rickettsia spp. showed a prevalence of 8.82% in 2009/2010 and 1.68% in 2019 with the exclusive detection of R. helvetica. The prevalence of Anaplasma spp. was 1.00% in 2009/2010 and 7.01% in 2019. A. phagocytophilum was detected in seven tick samples. None of the nymphs were positive for C. burnetii. Discussion: Here, observed changes in prevalence were not significant after a decade but require longitudinal observations including parameters like host species and density, climatic factors to improve our understanding of tick-borne diseases.

Stomach as the target organ of Rickettsia heilongjiangensis infection in C57BL/6 mice identified by click chemistry.

Spotted fever group rickettsiae (SFGR) are obligate intracellular bacteria that cause spotted fever. The limitations of gene manipulation pose great challenges to studying the infection mechanisms of Rickettsia. By combining bioorthogonal metabolism and click chemistry, we developed a method to label R. heilongjiangensis via azide moieties and achieved rapid pathogen localization without complex procedures. Moreover, we constructed a C57BL/6 mice infection model by simulating tick bites and discovered that the stomach is the target organ of R. heilongjiangensis infection through in vivo imaging systems, which explained the occurrence of gastrointestinal symptoms following R. heilongjiangensis infection in some cases. This study offers a unique perspective for subsequent investigations into the pathogenic mechanisms of SFGR and identifies a potential target organ for R. heilongjiangensis.

Genetic diversity and prevalence of emerging Rickettsiales in Yunnan Province: a large-scale study.

BACKGROUND: Rickettsia and related diseases have been identified as significant global public health threats. This study involved comprehensive field and systematic investigations of various rickettsial organisms in Yunnan Province. METHODS: Between May 18, 2011 and November 23, 2020, field investigations were conducted across 42 counties in Yunnan Province, China, encompassing small mammals, livestock, and ticks. Preliminary screenings for Rickettsiales involved amplifying the 16S rRNA genes, along with additional genus- or species-specific genes, which were subsequently confirmed through sequencing results. Sequence comparisons were carried out using the Basic Local Alignment Search Tool (BLAST). Phylogenetic relationships were analyzed using the default parameters in the Molecular Evolutionary Genetics Analysis (MEGA) program. The chi-squared test was used to assess the diversities and component ratios of rickettsial agents across various parameters. RESULTS: A total of 7964 samples were collected from small mammals, livestock, and ticks through Yunnan Province and submitted for screening for rickettsial organisms. Sixteen rickettsial species from the genera Rickettsia, Anaplasma, Ehrlichia, Neoehrlichia, and Wolbachia were detected, with an overall prevalence of 14.72%. Among these, 11 species were identified as pathogens or potential pathogens to humans and livestock. Specifically, 10 rickettsial organisms were widely found in 42.11% (24 out of 57) of small mammal species. High prevalence was observed in Dremomys samples at 5.60%, in samples from regions with latitudes above 4000 m or alpine meadows, and in those obtained from Yuanmou County. Anaplasma phagocytophilum and Candidatus Neoehrlichia mikurensis were broadly infecting multiple genera of animal hosts. In contrast, the small mammal genera Neodon, Dremomys, Ochotona, Anourosorex, and Mus were carrying individually specific rickettsial agents, indicating host tropism. There were 13 rickettsial species detected in 57.14% (8 out of 14) of tick species, with the highest prevalence (37.07%) observed in the genus Rhipicephalus. Eight rickettsial species were identified in 2375 livestock samples. Notably, six new Rickettsiales variants/strains were discovered, and Candidatus Rickettsia longicornii was unambiguously identified. CONCLUSIONS: This large-scale survey provided further insight into the high genetic diversity and overall prevalence of emerging Rickettsiales within endemic hotspots in Yunnan Province. The potential threats posed by these emerging tick-borne Rickettsiales to public health warrant attention, underscoring the need for effective strategies to guide the prevention and control of emerging zoonotic diseases in China.

Development of an all-in-one real-time PCR assay for simultaneous detection of spotted fever group rickettsiae, severe fever with thrombocytopenia syndrome virus and hantaan virus prevalent in central China.

Central China has been reported to be one of the most important endemic areas of zoonotic infection by spotted fever group rickettsiae (SFGR), severe fever with thrombocytopenia syndrome virus (SFTSV) and hantaan virus (HTNV). Due to similar clinical symptoms, it is challenging to make a definite diagnosis rapidly and accurately in the absence of microbiological tests. In the present study, an all-in-one real-time PCR assay was developed for the simultaneous detection of nucleic acids from SFGR, SFTSV and HTNV. Three linear standard curves for determining SFGR-ompA, SFTSV-L and HTNV-L were obtained within the range of 101-106 copies/µL, with the PCR amplification efficiencies ranging from 93.46% to 96.88% and the regression coefficients R2 of >0.99. The detection limit was 1.108 copies/µL for SFGR-ompA, 1.075 copies/µL for SFTSV-L and 1.006 copies/µL for HTNV-L, respectively. Both the within-run and within-laboratory coefficients of variation on the cycle threshold (Ct) values were within the range of 0.53%-2.15%. It was also found there was no statistical difference in the Ct values between single template and multiple templates (PSFGR-ompA = 0.186, PSFTSV-L = 0.612, PHTNV-L = 0.298). The sensitivity, specificity, positive and negative predictive value were all 100% for determining SFGR-ompA and SFTSV-L, 97%, 100%, 100% and 99.6% for HTNV-L, respectively. Therefore, the all-in-one real-time PCR assay appears to be a reliable, sensitive, rapid, high-throughput and low cost-effective method to diagnose the zoonotic infection by SFGR, SFTSV and HTNV.

First report of unusual case of parasitism by Amblyomma nodosum (Neumann, 1889) in a yellow cururu toad (Rhinella icterica) in the Northeastern Brazilian Caatinga.

The Amblyomma genus (Arachnida: Ixodidae) is widely distributed in South America, with 34 species occurring in Brazil. Amblyomma nodosum Neumann 1889 is a species that predominantly feeds on Passeriformes during immature stages (larvae and nymphs) and anteaters (Myrmecophagidae) during adult stages. The aim of the present study is to report, for the first time, an unusual case of parasitism by adults of A. nodosum on a yellow cururu toad (Rhinella icterica) captured in the city of Nossa Senhora da Glória, Sergipe state (Northeastern Brazil) in the Caatinga biome, and also investigate the presence of DNA of Rickettsia in the collected material. DNA was extracted from all specimens collected (N=8) and subjected to PCR assays based on the tick 16S rRNA endogenous gene and gltA gene for Rickettsia sp. All samples (8/8; 100%) were positive for the 16S rRNA endogenous gene and two amplicons (obtained from one male and one female) were purified and sequenced. The BLASTn analysis of the sequences revealed a high degree of similarity (95-100%) with A. nodosum sequences previously deposited on GenBank, while the phylogenetic analysis clustered the sequences obtained in the same clade as A. nodosum sequences from Brazil.

Cell-selective proteomics reveal novel effectors secreted by an obligate intracellular bacterial pathogen.

Pathogenic bacteria secrete protein effectors to hijack host machinery and remodel their infectious niche. Rickettsia spp. are obligate intracellular bacteria that can cause life-threatening disease, but their absolute dependence on the host cell has impeded discovery of rickettsial effectors and their host targets. We implemented bioorthogonal non-canonical amino acid tagging (BONCAT) during R. parkeri infection to selectively label, isolate, and identify effectors delivered into the host cell. As the first use of BONCAT in an obligate intracellular bacterium, our screen more than doubles the number of experimentally validated effectors for the genus. The seven novel secreted rickettsial factors (Srfs) we identified include Rickettsia-specific proteins of unknown function that localize to the host cytoplasm, mitochondria, and ER. We further show that one such effector, SrfD, interacts with the host Sec61 translocon. Altogether, our work uncovers a diverse set of previously uncharacterized rickettsial effectors and lays the foundation for a deeper exploration of the host-pathogen interface.

Rickettsia induces strong cytoplasmic incompatibility in a predatory insect.

Rickettsia, a group of intracellular bacteria found in eukaryotes, exhibits diverse lifestyles, with some acting as vertebrate pathogens transmitted by arthropod vectors and others serving as maternally transmitted arthropod endosymbionts, some of which manipulate host reproduction for their own benefit. Two phenotypes, namely male-killing and parthenogenesis induction are known as Rickettsia-induced host reproductive manipulations, but it remains unknown whether Rickettsia can induce other types of host manipulation. In this study, we discovered that Rickettsia induced strong cytoplasmic incompatibility (CI), in which uninfected females produce no offspring when mated with infected males, in the predatory insect Nesidiocoris tenuis (Hemiptera: Miridae). Molecular phylogenetic analysis revealed that the Rickettsia strain was related to Rickettsia bellii, a common insect endosymbiont. Notably, this strain carried plasmid-encoded homologues of the CI-inducing factors (namely cifA-like and cifB-like genes), typically found in Wolbachia, which are well-known CI-inducing endosymbionts. Protein domain prediction revealed that the cifB-like gene encodes PD-(D/E)XK nuclease and deubiquitinase domains, which are responsible for Wolbachia-induced CI, as well as ovarian tumour-like (OTU-like) cysteine protease and ankyrin repeat domains. These findings suggest that Rickettsia and Wolbachia endosymbionts share underlying mechanisms of CI and that CI-inducing ability was acquired by microbes through horizontal plasmid transfer.

Molecular Detection of Tick-Borne Pathogens in Kumasi: With a First Report of Zoonotic Pathogens in Abattoir Workers.

Tick-borne pathogens continue to infect humans and animals worldwide. By adapting to the movement of livestock, ticks facilitate the spread of these infectious pathogens. Humans in close contact with animals that could be amplifying hosts are especially at risk of being infected with tick-borne pathogens. This study involved the collection of dry blood spots (DBSs) to determine tick-borne pathogens occurring in slaughtered livestock and abattoir workers in Kumasi. This study employed the use of conventional PCR, RT-PCR, and Sanger sequencing to detect and identify the tick-borne pathogens. The resulting data was analysed using Stata version 13. A total of 175 DBSs were collected from goats (76), cattle (54), and sheep (45) in the Kumasi abattoir (130, 74.29%) and Akwatia Line slaughter slab (45, 25.71%). The pathogens identified were mostly bacterial including Anaplasma capra (9.71%), Anaplasma phagocytophilum (1.14%), and Rickettsia aeschlimannii (0.57.%). The only parasite identified was Theileria ovis (9.14%). A significant association was seen between A. capra (p < 0.001) infection and female sheep sampled from the Akwatia Line slaughter slab. Again, there was a significant association between T. ovis (p < 0.001) infections and female sheep from the Kumasi abattoir. From the human DBS (63) screened, the pathogens identified were all bacterial including Coxiella burnetii (1.89%), Rickettsia africae (1.89%), and R. aeschlimannii (1.89%). This study reports the first detection of R. aeschlimannii in livestock as well as the occurrence of the above-mentioned pathogens in humans in Ghana. Animals can serve as amplifying hosts for infectious pathogens; hence, there is an increased risk of infections among the abattoir workers. Continuous surveillance effort is essential, and abattoir workers need to protect themselves from tick bites and infectious tick-borne pathogens.

Spatial patterns of Hyalomma marginatum-borne pathogens in the Occitanie region (France), a focus on the intriguing dynamics of Rickettsia aeschlimannii.

Hyalomma marginatum is an invasive tick species recently established in mainland southern France. This tick is known to host a diverse range of human and animal pathogens. While information about the dynamics of these pathogens is crucial to assess disease risk and develop effective monitoring strategies, few data on the spatial dynamics of these pathogens are currently available. We collected ticks in 27 sites in the Occitanie region to characterize spatial patterns of H. marginatum-borne pathogens. Several pathogens have been detected: Theileria equi (9.2%), Theileria orientalis (0.2%), Anaplasma phagocytophilum (1.6%), Anaplasma marginale (0.8%), and Rickettsia aeschlimannii (87.3%). Interestingly, we found a spatial clustered distribution for the pathogen R. aeschlimannii between two geographically isolated areas with infection rates and bacterial loads significantly lower in Hérault/Gard departments (infection rate 78.6% in average) compared to Aude/Pyrénées-Orientales departments (infection rate 92.3% in average). At a smaller scale, R. aeschlimannii infection rates varied from one site to another, ranging from 29% to 100%. Overall, such high infection rates (87.3% on average) and the effective maternal transmission of R. aeschlimannii might suggest a role as a tick symbiont in H. marginatum. Further studies are thus needed to understand both the status and the role of R. aeschlimannii in H. marginatum ticks.IMPORTANCETicks are obligatory hematophagous arthropods that transmit pathogens of medical and veterinary importance. Pathogen infections cause serious health issues in humans and considerable economic loss in domestic animals. Information about the presence of pathogens in ticks and their dynamics is crucial to assess disease risk for public and animal health. Analyzing tick-borne pathogens in ticks collected in 27 sites in the Occitanie region, our results highlight clear spatial patterns in the Hyalomma marginatum-borne pathogen distribution and strengthen the postulate that it is essential to develop effective monitoring strategies and consider the spatial scale to better characterize the circulation of tick-borne pathogens.

Reassessment of the genetic basis of natural rifampin resistance in the genus Rickettsia.

Rickettsia, a genus of obligate intracellular bacteria, includes species that cause significant human diseases. This study challenges previous claims that the Leucine-973 residue in the RNA polymerase beta subunit is the primary determinant of rifampin resistance in Rickettsia. We investigated a previously untested Rickettsia species, R. lusitaniae, from the Transitional group and found it susceptible to rifampin, despite possessing the Leu-973 residue. Interestingly, we observed the conservation of this residue in several rifampin-susceptible species across most Rickettsia phylogenetic groups. Comparative genomics revealed potential alternative resistance mechanisms, including additional amino acid variants that could hinder rifampin binding and genes that could facilitate rifampin detoxification through efflux pumps. Importantly, the evolutionary history of Rickettsia genomes indicates that the emergence of natural rifampin resistance is phylogenetically constrained within the genus, originating from ancient genetic features shared among a unique set of closely related Rickettsia species. Phylogenetic patterns appear to be the most reliable predictors of natural rifampin resistance, which is confined to a distinct monophyletic subclade known as Massiliae. The distinctive features of the RNA polymerase beta subunit in certain untested Rickettsia species suggest that R. raoultii, R. amblyommatis, R. gravesii, and R. kotlanii may also be naturally rifampin-resistant species.

Island hitchhikers: pathogen agents of Madeira and Azores ticks.

Ticks are blood-sucking arthropods that can transmit pathogens to their host. As insular ecosystems can enhance tick-host interactions, this study aimed to understand tick diversity, pathogen presence, and their respective associations in the Azores and Madeira archipelagos. Unfed or partially engorged ticks (n = 120) were collected from 58 cats and dogs in the Azores (n = 41 specimens) and Madeira (n = 79 specimens) from November 2018 to March 2019. Vector identification was based on morphology and molecular criteria. For pathogen sequencing, 18S gene fragment for Babesia/Hepatozoon and gltA for Rickettsia were performed. Sequence data was explored using BLAST and BLAST and phylogenetic inference tools. In the Azores, Ixodes hexagonus, I. ventalloi, and Rhipicephalus sanguineus (n = 6; 14.6%, n = 6; 14.6%, and n = 29; 70.7% respectively) were found and in Madeira I. ricinus and R. sanguineus (n = 78, 98.7%; and n = 1, 1.3%; respectively) were identified. Tick COI markers confirmed species highlighting confirmation of R. sanguineus s.s. and genotype A of I. ventalloi. In the Azores Islands, the detected Rickettsia massiliae was linked to R. sanguineus (dogs and cats) and I. hexagonus (dogs), and in Madeira Island, R. monacensis (dogs) and Hepatozoon silvestris (cats) were found associated with I. ricinus. Further, I. ventalloi presence in the Azores expands west its known range, and Hepatozoon silvestris in Madeira may suggest that I. ricinus could have a role as a potential vector. Finally, as R. massiliae and R. monacensis presence underlines public health risks, surveillance by health authorities is crucial as pathogen-tick interactions may drive disease spread, therefore monitoring remains pivotal for disease prevention.

Japanese spotted fever complicated with pleural effusion in Zhejiang province, China: a case report and literature review.

INTRODUCTION: Japanese spotted fever (JSF) mainly occurs in Japan; however, it has been increasingly reported in China. JSF is typically characterized by fever, rash, and eschar, in addition to non-specific symptoms. Yet, reports on the pulmonary indicators in JSF are limited. Herein, we report an unusual case of JSF associated with pleural effusion and pneumonia, in which the pathogen was identified via blood next-generation sequencing (NGS). CASE PRESENTATION: We report a case of a 33-year-old woman who presented with fever for five days, rash for two days, and myalgia, fatigue, and edema for one day. She had recently been on vacation when an unknown insect bit her. The doctors at the local primary hospital considered a bacterial infection and administered dexamethasone, ceftriaxone, indomethacin, and anti-allergy agents, but the symptoms persisted. A rash without pruritus or pain developed gradually over the entire body and face. We considered rickettsial infection and administered doxycycline and levofloxacin. Metagenomic NGS from blood confirmed the presence of Rickettsia japonica (R. japonica). Abdominal computed tomography revealed bilateral pleural effusion with two atelectasis; patchy shadows with blurred edges, and uniform enhancement in both lower lungs. After several days of treatment, the symptoms and laboratory results improved. A literature review of the epidemiology of R. japonica and JSF in China, characteristics of JSF, and related pulmonary changes, and technology to diagnose JSF is provided. CONCLUSIONS: JSF has a variety of symptoms and is becoming increasingly popular in China. Clinical doctors need to identify it carefully.

Evaluating the circulation of Ehrlichia canis and Rickettsia spp. in domestic dogs from a semiarid region in Brazil.

Tick-borne diseases are important for animal and human health, because they can cause death if not diagnosed and treated early. Canine monocytic ehrlichiosis (CME) can cause high morbidity in dog populations. Rocky Mountain Spotted Fever (RMSF) is among the most virulent infectious in humans; dogs are also susceptible to infection. The aims of this study were to evaluate the presence of Ehrlichia canis and Rickettsia spp. infections in domestic dogs, and to identify tick species parasitizing dogs among urban areas of two municipalities (Sobral and Alcântaras) in the Ceará State, Northeastern Brazil. A total of 208 domiciled dogs was sampled. After clinical evaluation, blood samples and ticks were collected and submitted to Real-Time Polymerase Chain Reaction (RT-PCR) targeting E. canis DNA. Serum samples were screened by Indirect Immunofluorescence Assays (IFA) for antibodies against different strains of Rickettsia spp. previously recognized in Brazil. The results of this study indicate the molecular detection of E. canis in the state of Ceará, Brazil, where the proportion of canine infection in Sobral (9.9%) was higher than in Alcântaras (5.6%). Rhipicephalus sanguineus sensu lato was the prevalent tick species infesting the dogs in both municipalities (43.5 and 53.3%, respectively). Our serological results indicate that dogs of the study area were at low risk of exposure to these tick-borne Rickettsia spp. of the spotted fever group. Our study offers epidemiological data of these diseases to better understanding Rickettsiales epidemic and enzootic cycles in the Brazilian semiarid region, improving prevention and control measures.

Infestation prevalence, spatio-temporal distribution, phylogenetic positioning, and pathogen investigation of Argas persicus ticks in domestic hens (Gallus gallus domesticus) from Pakistan.

Soft ticks pose significant health risks as vectors of various pathogens. This study explored the spatio-temporal distribution and genetic relationships of the soft tick species Argas persicus infesting domestic hens (Gallus gallus domesticus) across different districts in Pakistan. An examination of 778 hens revealed a notable tick infestation prevalence of 70.82%, with a total of 1299 ticks collected from 551 hens. The overall mean intensity was 2.19 soft ticks per infested chicken, and the overall mean abundance was 1.61 soft ticks per examined hen. Morphological identification confirmed all collected ticks (n = 1210) as A. persicus, comprising 719 males, 333 females, 121 nymphs, and 38 larvae. The Haveli, Muzaffarabad, and Kotli districts had the highest infestation rates, while Bagh had the lowest. Molecular analyses of tick DNA, focusing on 16S rDNA and 12S rDNA sequences, revealed genetic similarities among A. persicus soft ticks from Pakistan and other regions, providing insights into their evolutionary history. Importantly, no Babesia, Rickettsia, or Anaplasma infections were detected in the examined samples. These findings enhance the understanding of soft tick infestation patterns and the genetic diversity of A. persicus in the studied region.

[Investigation of tick - borne Rickettsia in selected areas of Liupanshui City, Guizhou Province in 2023].

OBJECTIVE: To investigate the prevalence of tick-borne rickettsial infections in selected areas of Liupanshui City, Guizhou Province, 2023, so as to provide insights into the management of tick-borne rickettsioses in the city. METHODS: Ticks were captured from the body surface of bovines and sheep in Gaoxing Village, Dashan Township, Liupanshui City, Guizhou Province during the period between April and June, 2023, and tick species were identified using morphological and molecular biological techniques. In addition, tick-borne Rickettsia was identified using a nested PCR assay, including spotted fever group rickettsiae (SFGR), Coxiella spp., Anaplasma spp., Ehrlichia spp., and Orientia spp., and positive amplified fragments were sequenced and aligned with known sequences accessed in the GenBank database. RESULTS: A total of 200 ticks were collected and all tick species were identified as Rhipicephalus microplus. Nestle PCR assay combined with sequencing identified ticks carrying Candidatus Rickettsia jingxinensis (40.50%), Coxiella burnetii (1.50%), and Coxiella-like endosymbionts (27.00%), and Anaplasma spp., Ehrlichia spp. or Orientsia spp. was not detected. CONCLUSIONS: R. microplus carried Candidatus R. jingxinensis, C. burnetii, and Coxiella-like endosymbionts in selected areas of Liupanshui City, Guizhou Province. Intensified monitoring of tickborne rickettsial infections is needed in livestock and humans to reduce the damages caused by rickettsioses.

Bacterial pathogens in Ixodes ricinus collected from lizards Lacerta agilis and Zootoca vivipara in urban areas of Wroclaw, SW Poland- preliminary study.

The aim of this study was to determine the level of infection of Ixodes ricinus ticks with pathogens (Borrelia spp., Rickettsia spp., and Anaplasma spp.) collected from Lacerta agilis and Zootoca vivipara lizards in the urban areas of Wroclaw (SW Poland). The study was carried out in July-August 2020. Lizards were caught by a noose attached to a pole or by bare hands, identified by species, and examined for the presence of ticks. Each lizard was then released at the site of capture. Ticks were removed with tweezers, identified by species using keys, and molecular tests were performed for the presence of pathogens. From 28 lizards (17 specimens of Z. vivipara and 11 specimens of L. agilis) a total of 445 ticks, including 321 larvae and 124 nymphs, identified as I. ricinus were collected. A larger number of ticks were obtained from L. agilis compared to Z. vivipara. Molecular tests for the presence of pathogens were performed on 445 specimens of I. ricinus. The nested PCR method for the fla gene allowed the detection of Borrelia spp. in 9.4% of ticks, and it was higher in ticks from L. agilis (12.0%) than from Z. vivipara (1.0%). The RFLP method showed the presence of three species, including two belonging to the B. burgdorferi s.l. complex (B. lusitaniae and B. afzelii), and B. miyamotoi. The overall level of infection of Rickettsia spp. was 19.3%, including 27.2% in ticks collected from Z. vivipara and 17.0% from L. agilis. Sequencing of randomly selected samples confirmed the presence of R. helvetica. DNA of Anaplasma spp. was detected only in one pool of larvae collected from L. agilis, and sample sequencing confirmed the presence of (A) phagocytophilum. The research results indicate the important role of lizards as hosts of ticks and their role in maintaining pathogens in the environment including urban agglomeration as evidenced by the first recorded presence of (B) miyamotoi and (A) phagocytophilum in I. ricinus ticks collected from L. agilis. However, confirmation of the role of sand lizards in maintaining (B) miyamotoi and A. phagocytophilum requires more studies and sampling of lizard tissue.

Rickettsia parkeri Rickettsiosis in Kidney Transplant Recipient, North Carolina, USA, 2023.

Spotted fever rickettsiosis is rarely observed in solid organ transplant recipients, and all previously reported cases have been associated with tick bite months to years after transplantation. We describe a kidney transplant recipient in North Carolina, USA, who had a moderately severe Rickettsia parkeri infection develop during the immediate posttransplant period.

Diversity of Rickettsia species in collected ticks from Southeast Iran.

Rickettsia occurs worldwide and rickettsiosis is recognized as an emerging infection in several parts of the world. Ticks are reservoir hosts for pathogenic Rickettsia species in humans and domestic animals. Most pathogenic Rickettsia species belong to the spotted Fever Group (SFG). This study aimed to identify and diagnose tick fauna and investigate the prevalence of Rickettsia spp. in ticks collected from domestic animals and dogs in the rural regions of Kerman Province, Southeast Iran. In this study, tick species (fauna) were identified and 2100 ticks (350 pooled samples) from two genera and species including Rhipicephalus linnaei (1128) and Hyalomma deteritum (972) were tested to detect Rickettsia genus using Real-time PCR. The presence of the Rickettsia genus was observed in 24.9% (95%CI 20.28-29.52) of the pooled samples. Sequencing and phylogenetic analyses revealed the presence of Rickettsia aeschlimannii (48.98%), Rickettsia conorii israelensis (28.57%), Rickettsia sibirica (20.41%), and Rickettsia helvetica (2.04%) in the positive samples. The results showed a significant association between county variables and the following variables: tick spp. (p < 0.001), Rickettsia genus infection in ticks (p < 0.001) and Rickettsia spp. (p < 0.001). In addition, there was a significant association between tick species and host animals (dogs and domestic animals) (p < 0.001), Rickettsia spp infection in ticks (p < 0.001), and Rickettsia spp. (p < 0.001). This study indicates a high prevalence of Rickettsia spp. (SFG) in ticks of domestic animals and dogs in rural areas of Kerman Province. The health system should be informed of the possibility of rickettsiosis and the circulating species of Rickettsia in these areas.

Rickettsia symbionts spread via mixed mode transmission, increasing female fecundity and sex ratio shift by host hormone modulating.

Heritable symbionts are common among animals in nature, but the molecular mechanisms underpinning symbiont invasions of host populations have been elusive. In this study, we demonstrate the spread of Rickettsia in an invasive agricultural pest, the whitefly Bemisia tabaci Mediterranean (MED), across northeastern China from 2018 to 2023. Here, we show that the beneficial symbiont Rickettsia spreads by manipulating host hormone signals. Our analyses suggest that Rickettsia have been horizontally acquired by B. tabaci MED from another invasive whitefly B. tabaci Middle East-Asia Minor 1 during periods of coexistence. Rickettsia is transmitted maternally and horizontally from female B. tabaci MED individuals. Rickettsia infection enhances fecundity and results in female bias among whiteflies. Our findings reveal that Rickettsia infection stimulates juvenile hormone (JH) synthesis, in turn enhancing fecundity, copulation events, and the female ratio of the offspring. Consequently, Rickettsia infection results in increased whitefly fecundity and female bias by modulating the JH pathway. More female progeny facilitates the transmission of Rickettsia. This study illustrates that the spread of Rickettsia among invasive whiteflies in northeastern China is propelled by host hormone regulation. Such symbiont invasions lead to rapid physiological and molecular evolution in the host, influencing the biology and ecology of an invasive species.