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.

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.

Duplex Reverse-Transcription Real-Time Polymerase Chain Reaction Assay Targeting 23S rRNA Single Nucleotide Polymorphisms for the Detection of Flea-Borne Rickettsioses.

Flea-borne spotted fever and flea-borne (murine) typhus are rickettsioses caused by Rickettsia felis and Rickettsia typhi, respectively, and typically present as undifferentiated febrile illnesses. The relative contribution of these agents to flea-borne rickettsioses in California is unclear. We have developed a duplex reverse transcription real-time polymerase chain reaction (RT-rtPCR) assay targeting R. felis- and R. typhi-specific 23S ribosomal RNA single nucleotide polymorphisms to better understand the respective roles of these agents in causing flea-borne rickettsioses in California. This assay was compared with an established duplex R. felis- and R. typhi-ompB rt-PCR assay and was shown to have 1,000-fold and 10-fold greater analytical sensitivity for the detection of R. felis and R. typhi, respectively. Retrospective testing of clinical specimens with both assays established R. typhi as the major etiologic agent of flea-borne rickettsioses in California.

[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.

Knowledge, attitudes, and practices (KAPs) regarding tick-borne rickettsial disease among medical staff in endemic areas of China.

Tick-borne rickettsial disease (TBRD) is a perilous acute infection that often eludes diagnosis in its early stages. The triad of knowledge, attitudes, and practices (KAPs) among medical professionals is key to reducing missed diagnosis rates. Therefore, a meticulous evaluation of KAPs is imperative. This study aimed to delve into the understanding of TBRD and explore the beliefs and practices related to personal prevention methods among individuals in Lu'an, a hotspot for TBRD. During the summer months of 2023, convenience sampling was employed by circulating a confidential questionnaire to 1,206 participants in the endemic regions of China. This questionnaire painted a comprehensive picture of the participants' sociodemographic profiles and their KAPs levels vis-à-vis TBRD. The findings revealed that participants scored a mere 55.78% in knowledge, while their attitudes and practices garnered impressive scores of 90.09% and 90.83%, respectively. Upon further analysis using multiple linear regression, several intriguing patterns emerged. Male participants, employed in the Infectious Disease Department, held vice-senior or higher titles, or had prior medical training demonstrated superior knowledge scores. On the other hand, medical personnel who were younger than 30, possessed graduate degrees or higher qualifications, and had training excelled in attitudes and practices. Notably, when employing the Boston Consulting Group (BCG) matrix, a significant distribution of medical personnel was observed across the four quadrants. Specifically, 37.43%, 13.19%, 19.61%, and 29.77% fell into the first, second, third, and fourth quadrants. This survey underscores the commendable attitudes and practices of medical staff towards TBRD in endemic regions of China. However, their knowledge level remains wanting and demands urgent improvement.

Leptospira spp. and Rickettsia spp. as pathogens with zoonotic potential causing acute undifferentiated febrile illness in a central-eastern region of Peru.

OBJETIVE: this study was to determine the relationship between acute febrile illness and bacterial pathogens with zoonotic potential that cause emerging and re-emerging diseases in a central-eastern region of Peru. RESULTS: Out of the 279 samples analyzed, 23 (8.2%) tested positive for infection by Rickettsia spp., while a total of 15 (5.4%) tested positive for Leptospira spp. Women had a higher frequency of infection by Rickettsia spp., with 13 cases (53.3%), while men had a higher frequency of infection by Leptospira spp., with 10 cases (66.7%). The most frequently reported general symptom was headache, with 100.0% (n = 23) of patients with Rickettsia (+) and 86.7% (n = 13) of patients with Leptospira (+) experiencing it. Arthralgia was the second most frequent symptom, reported by 95.6% (n = 22) and 60% (n = 9) of patients with Rickettsia (+) and Leptospira (+), respectively. Myalgia was reported by 91.3% (n = 21) and 66.7% (n = 10) of patients with Rickettsia (+) and Leptospira (+), respectively. Retroocular pain, low back pain, and skin rash were also present, but less frequently. Among the positives, no manifestation of bleeding was recorded, although only one positive case for Leptospira spp. presented a decrease in the number of platelets.

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.

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.

Rickettsia africae infections in sub-Saharan Africa: A systematic literature review of epidemiological studies and summary of case reports.

Rickettsia africae is a tick-borne bacteria known to cause African tick bite fever (ATBF). While the disease was first described more than 100 years ago, knowledge of transmission risk factors and disease burden remain poorly described. To better understand the burden of R. africae, this article reviewed and summarized the published literature related to ATBF epidemiology and clinical management. Using a systematic approach, consistent with the PRISMA guidelines, we identified more than 100 eligible articles, including 65 epidemiological studies and 41 case reports. Most reports described R. africae in ticks and livestock, while human studies were less common. Human disease case reports were exclusively among returning travellers from non-endemic areas, which limits our disease knowledge among at-risk populations: people living in endemic regions. Substantial efforts to elucidate the ATBF risk factors and clinical manifestations among local populations are needed to develop effective preventative strategies and facilitate appropriate and timely diagnosis.

First detection of Rickettsia felis and Ehrlichia canis in the common bed bug Cimex lectularius.

Bed bugs, common blood-feeding pests, have received limited attention regarding their potential involvement in emerging pathogen transmission. This study aimed to investigate the main vector-borne bacteria within bed bugs collected from Tunisian governorates and to genetically characterize the identified species. Molecular screening was conducted on field-collected bed bug samples, targeting zoonotic vector-borne bacteria from the Anaplasmataceae family, as well as the genera Rickettsia, Ehrlichia, Bartonella, and Borrelia. A total of 119 Cimex lectularius specimens were collected and grouped into 14 pools based on sampling Tunisian sites. Using genus-specific PCR assays, DNA of Rickettsia and Ehrlichia spp. was detected in a single pool. Sequencing and BLAST analysis of the obtained partial ompB and dsb sequences from positive samples revealed 100% similarity with those of Ehrlichia canis and Rickettsia felis available in GenBank. Obtained partial sequences showed phylogenetic similarity to R. felis and E. canis isolates found in dogs and ticks from American and European countries. To the best of our knowledge, this study is the first to investigate bed bugs in Tunisia and to report the worldwide identification of R. felis and E. canis DNA in the common bed bug, C. lectularius. These findings highlight the need for further research to explore the potential role of bed bugs in the epidemiology of these vector-borne bacteria.

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.

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.

Identification of Bacteria and Viruses Associated with Patients with Acute Febrile Illness in Khon Kaen Province, Thailand.

The majority of cases of undifferentiated acute febrile illness (AFI) in the tropics have an undefined etiology. In Thailand, AFI accounts for two-thirds of illnesses reported to the Ministry of Public Health. To characterize the bacterial and viral causes of these AFIs, we conducted molecular pathogen screening and serological analyses in patients who sought treatment in Chum Phae Hospital, Khon Kaen province, during the period from 2015 to 2016. Through integrated approaches, we successfully identified the etiology in 25.5% of cases, with dengue virus infection being the most common cause, noted in 17% of the study population, followed by scrub typhus in 3.8% and rickettsioses in 6.8%. Further investigations targeting viruses in patients revealed the presence of Guadeloupe mosquito virus (GMV) in four patients without other pathogen co-infections. The characterization of four complete genome sequences of GMV amplified from AFI patients showed a 93-97% nucleotide sequence identity with GMV previously reported in mosquitoes. Nucleotide substitutions resulted in amino acid differences between GMV amplified from AFI patients and mosquitoes, observed in 37 positions. However, these changes had undergone purifying selection pressure and potentially had a minimal impact on protein function. Our study suggests that the GMV strains identified in the AFI patients are relatively similar to those previously reported in mosquitoes, highlighting their potential role associated with febrile illness.

Emergent spotted fever group Rickettsiae infections among hard ticks in Islamic Republic of Iran.

Background: Tick-borne rickettsioses have become a health concern worldwide following the increasing incidence in recent decades. However, there is limited information about these diseases in Islamic Republic of Iran. Aim: This cross-sectional study was conducted to estimate the Rickettsia infection among ixodid ticks collected from cattle, sheep and goats in Islamic Republic of Iran. Methods: The DNA of ixodid ticks collected from cattle, sheep and goats in 54 villages of Zanjan Province, Islamic Republic of Iran, were collected and analysed using a spectrophotometer. Rickettsial-positive samples were screened by targeting the htrA gene and fragments of gltA gene were analysed. The variables were analysed using descriptive statistics and the χ2 test was used to compare the variables. Results: A total of 528 ticks were tested. Overall, Rickettsia infection rate was 6.44%. Nine of the 12 tick species were infected. Rickettsial positive rates in Hyalomma marginatum and Dermacentor marginatus were 21.33% and 12.77%, respectively. R. aeschlimannii, the predominant rickettsia, was detected only in Hy. marginatum. R. raoultii, R. sibirica and R. slovaca comprised about half of the positive ticks and were recovered from more than one tick species. Conclusion: Considering the discovery of infected ticks in the Islamic Republic of Iran, there is a need to establish a tick control programme in the country, paying attention to populations at high-risk.

Prevalence and risk factors for Q fever, spotted fever group rickettsioses, and typhus group rickettsioses in a pastoralist community of northern Tanzania, 2016-2017.

BACKGROUND: In northern Tanzania, Q fever, spotted fever group (SFG) rickettsioses, and typhus group (TG) rickettsioses are common causes of febrile illness. We sought to describe the prevalence and risk factors for these zoonoses in a pastoralist community. METHODS: Febrile patients ≥2 years old presenting to Endulen Hospital in the Ngorongoro Conservation Area were enrolled from August 2016 through October 2017. Acute and convalescent blood samples were collected, and a questionnaire was administered. Sera were tested by immunofluorescent antibody (IFA) IgG assays using Coxiella burnetii (Phase II), Rickettsia africae, and Rickettsia typhi antigens. Serologic evidence of exposure was defined by an IFA titre ≥1:64; probable cases by an acute IFA titre ≥1:128; and confirmed cases by a ≥4-fold rise in titre between samples. Risk factors for exposure and acute case status were evaluated. RESULTS: Of 228 participants, 99 (43.4%) were male and the median (interquartile range) age was 27 (16-41) years. Among these, 117 (51.3%) had C. burnetii exposure, 74 (32.5%) had probable Q fever, 176 (77.2%) had SFG Rickettsia exposure, 134 (58.8%) had probable SFG rickettsioses, 11 (4.8%) had TG Rickettsia exposure, and 4 (1.8%) had probable TG rickettsioses. Of 146 participants with paired sera, 1 (0.5%) had confirmed Q fever, 8 (5.5%) had confirmed SFG rickettsioses, and none had confirmed TG rickettsioses. Livestock slaughter was associated with acute Q fever (adjusted odds ratio [OR] 2.54, 95% confidence interval [CI] 1.38-4.76) and sheep slaughter with SFG rickettsioses case (OR 4.63, 95% CI 1.08-23.50). DISCUSSION: Acute Q fever and SFG rickettsioses were detected in participants with febrile illness. Exposures to C. burnetii and to SFG Rickettsia were highly prevalent, and interactions with livestock were associated with increased odds of illness with both pathogens. Further characterisation of the burden and risks for these diseases is warranted.

Changes in the Seroprevalence of Tick-Borne Rickettsia and Ehrlichia Among Soldiers-Fort Liberty, North Carolina, 1991-2019.

We obtained samples from the Department of Defense Serum Repository from soldiers who were stationed at Fort Liberty, North Carolina, between 1991 and 2019 to assess temporal trends in tick-borne rickettsiosis and ehrlichiosis. Serological evidence of infection was common, with nearly 1 in 5 (18.9%) demonstrating antibodies. We observed significant decreases in Rickettsia seroprevalence (adjusted odds ratio [aOR], 0.42 [95% CI, .27-.65], P = .0001) while over the same period Ehrlichia seroprevalence, albeit less common, nearly doubled (aOR, 3.61 [95% CI, 1.10-13.99], P = .048). The increase in Ehrlichia seroprevalence likely reflects increased transmission resulting from the expanding geographic range of the lone star tick.

Distribution of different Rickettsia species in countries of the WHO Eastern Mediterranean (WHO-EMRO) region: An overview.

SUBJECT: Rickettsia is a zoonotic bacterial pathogen transmitted by vectors and has extensive reservoirs in animal and human populations. Rickettsiosis is a public health problem all over the world. However, comprehensive information on the geographical distribution of different Rickettsia species, infection status of reservoirs, vectors, and human cases is lacking in most parts of the world. Therefore, this study aimed to investigate the geographical distribution of different Rickettsia species and their vectors in countries of the WHO-EMRO region. METHODS: In this review study, a search was conducted for reports and published studies on Rickettsia species from WHO-EMRO region countries in various databases from 1995 to 2022. Finally, the reported status of human cases, reservoirs, and vectors associated with each species in different countries was documented. RESULTS: Reports of infections related to the detection of Rickettsia species were only available for 15 out of 22 WHO-EMRO member countries. A total of twenty-four Rickettsia species, including R. sibrica, R. lusitaniae, R. africae, R. prowazekii, R. felis, R. typhi, R. rickettsii, R. aeschlimannii, R. conorii, R. massiliae, R. helvetica, R. monacensis, R. rhipicephali, R. bellii, R. asembonensis, R. hoogstraalii, R. andeanae, R. raoultii, R. asiatica, R. slovaca, R. australis, R. barbariae, Candidatus R. amblyommii, and Candidatus R. goldwasserii, were reported from WHO-EMRO member countries. Furthermore, human cases infected with six different Rickettsia species, including R. sibrica, R. prowazekii, R. felis, R. typhi, R. rickettsii, R. aeschlimannii, R. conorii, R. massiliae, and R. helvetica, were reported from these countries. CONCLUSION: The vast diversity of Rickettsia vectors has contributed to the ongoing discovery of new Rickettsia species. Therefore, further research on the reservoir hosts of Rickettsia infections in the understudied WHO-EMRO region is crucial. This research sheds light on Rickettsia disease's epidemiology and transmission dynamics in this region.

Prevalence of Anaplasma, Ehrlichia and Rickettsia infections in dogs in Iran: A meta-analysis study.

The current study aims to assess the prevalence of different genera of Rickettsiales, intracellular bacteria, in dogs across various regions of Iran. Rickettsiales, as zoonotic pathogens, can have various manifestations in different species, including immunosuppression, anaemia and neuropathy. Due to their close interactions with people and livestock, dogs can serve as reservoirs and transmit these pathogens to humans and other animals. The data from this research can be valuable for managing and controlling related diseases and complications in Iran and possibly neighbouring countries. Pertinent data for this study was gathered without time limitations until 1 March 2022, from different databases. Of all the inspected studies, 26 were eligible based on the inclusion criteria. The Egger test result and asymmetry in the funnel plot revealed significant publication bias; therefore, the meta-analysis model was corrected with the trim-and-fill method. After correction, the prevalence of rickettsial infections among dogs varies by genus - 20.1% for Anaplasma spp. and 10% for Ehrlichia spp. - with an overall prevalence estimated at 18.3% by random-effects analysis. The highest and lowest estimated pooled prevalences were associated with the southwestern (38.5%) and southern (0.3%) provinces of Iran, respectively. The pooled prevalence of rickettsial infection was higher in female dogs (OR = 1.198; p < 0.978; 95% CI, 0.842-1.705) and in dogs ≤2 years (OR = 1.014; p < 0.312; 95% CI, 0.598-1.72), but the difference was not statistically significant. Ultimately, the pooled prevalence of rickettsial infections among dogs is relatively low compared to other countries like Qatar, Iraq, Saudi Arabia and Turkey, which are nearby Iran. Given the significant clinical outcomes of this disease, necessary measures for prevention should be taken.

Changing epidemiologic patterns of typhus group rickettsiosis and scrub typhus in China, 1950-2022.

OBJECTIVES: We conducted a systematic analysis of the notifiable rickettsial diseases in humans in China during 1950-2022. METHODS: We utilized descriptive statistics to analyze the epidemiological characteristics, clinical manifestations, and diagnostic characteristics of typhus group rickettsiosis (TGR) and scrub typhus (ST) cases. RESULTS: Since the 1950s, there have been variations in the incidence rate of TGR and ST in China, with a downtrend for TGR and an uptrend for ST. The South became a high-incidence area of TGR, whereas the North was previously the high-incidence area. ST cases were concentrated in the South and the geographic area of ST spread northward and westward. The seasonality of TGR and ST were similar in the South but distinct in the North. Most TGR and ST cases were reported by county-level medical institutions, whereas primary institutions reported the least. Delayed diagnosis was associated with fatal outcomes of TGR and ST. Cases in low-incidence provinces, confirmed by laboratory tests and reported from county/municipal-level institutions had higher odds of delayed diagnoses. CONCLUSIONS: Our study revealed significant changes in the epidemiological characteristics of TGR and ST in China, which can provide useful information to enhance the control and prevention strategies of rickettsial diseases in China.