Fleaborne typhus (FBT) is reemerging as a major cause of febrile illness in California, USA. We performed enhanced testing on low-titer Rickettsia typhi antibody-positive specimens from patients with FBT-compatible illness reported in Los Angeles County, California, during 2022-2024. We tested 114 specimens by repeat serology and 113 by real-time PCR; 81 (71%) were PCR-positive, and 95 (83%) had higher antibody titers by repeat serology. Most PCR-positive specimens were collected 8-10 days after illness onset, but some were collected up to 15 days after illness onset. All PCR-positive specimens were R. typhi-specific. After additional testing, 113 (99%) suspected cases were reclassified as probable or confirmed FBT cases. Our findings indicate that many low-titer seropositive results represent true infections and that use of minimum serology thresholds for public health investigation underestimates surveillance case counts. Expanding commercial molecular testing capacity will improve clinical FBT diagnosis and enhance surveillance accuracy.

Vector-borne pathogens (VBPs) comprise a diverse range of pathogens, including viruses, bacteria, protozoa, and helminths, that are transmitted to vertebrate hosts by various species of arthropod vectors. The present study aimed to report the first data on the prevalence of VBPs in domestic cats in Kosovo and investigate associations with potential risk factors. Blood samples were collected from 107 domestic cats between April and October 2024 and preserved on filter papers. Samples were screened for VBPs, including Anaplasma spp., Ehrlichia spp., Babesia spp., Hepatozoon spp., Cytauxzoon spp., Bartonella spp., Filarioidea, Mycoplasma spp., Rickettsia spp., and Trypanosoma spp., using polymerase chain reaction (PCR), followed by sequence analysis. Haemotropic mycoplasma DNA was detected in 9 cats (8.4%, 95% CI: 4.2-15.8). Of the sequences obtained, three were identified as Mycoplasma haemofelis and six as Candidatus Mycoplasma haematominutum. The samples resulted negative for the presence of DNA from other VBPs. Significant variations in infection prevalence were associated with age, sex, outdoor access, and health status. This study provides the first molecular detection of Mycoplasma spp. infection in domestic cats from the capital region, Prishtina, and contributes to a better understanding of the epidemiology of this pathogen in the local feline population, which is essential for the development of effective preventive and control strategies.

Bacterial zoonoses constitute a significant proportion of emerging infectious diseases. Yet, the diversity and transmission cycles of many zoonotic bacteria remain poorly characterized, particularly in tropical, biodiverse regions where host and vector diversity are high, and the burden of zoonotic disease in human populations is substantial. In this study, we investigated the presence of five pathogenic bacterial genera-Rickettsia, Borrelia, Orientia, Leptospira, and Coxiella-in rodents from southern India. We detected low circulation of Rickettsia (7.26%), Borrelia (6.45%), and Leptospira (0.8%), with limited coinfections, whereas Orientia and Coxiella were not detected in the rodents sampled. Notably, we observed contrasting patterns of tissue association, with rickettsiae detected exclusively in pooled organ tissues and borreliae detected only in blood, suggesting the influence of pathogen biology in detection probabilities. Our phylogenetic analyses further confirmed that the detected Rickettsia and Borrelia belonged to the spotted fever group rickettsiae and relapsing fever group borreliae, respectively, in both synanthropic and forest-associated rats, highlighting a potential transmission risk to people and livestock in the region. By revealing the circulation of zoonotic bacteria in new host species, this study underscores the need for systematic surveillance of wildlife to better characterize bacterial diversity and its public health implications.

Acute disseminated encephalomyelitis (ADEM) is a rare, immune-mediated demyelinating disorder of the central nervous system that typically follows viral or bacterial infections. There are only two known case reports that describe an association with ADEM post rickettsial infection. A female in her 80s presented with progressive neurological decline, including dysarthria, dysphagia and hemiparesis, following recent treatment in Hong Kong for rickettsial infection. Initial CT brain imaging showed a right subcortical infarct. She deteriorated with encephalopathy and respiratory failure, requiring intubation. MRI revealed extensive brain and spinal demyelination. Infectious, autoimmune and paraneoplastic investigations were negative, while serology revealed markedly elevated spotted fever group antibodies. Treatment with high-dose corticosteroids and plasma exchange therapy resulted in significant neurological recovery. She was discharged after rehabilitation with a good recovery at 70%-80% of pre-morbid function. This case supports a possible post-infectious immune-mediated mechanism linking rickettsia and ADEM and underscores the importance of early recognition and treatment of ADEM.

Anthropogenic changes associated with urbanization can bring wildlife species into closer contact with livestock and humans, thereby increasing the risk of pathogen spillover. Recently, urban-adapted (synanthropic) hedgehog species, including Hemiechinus auritus (long-eared) and Paraechinus hypomelas (Brandt's), have been suggested as potential sources of zoonotic pathogens. The increasing number of tick-infested hedgehogs in urban areas and confirmed cases of human rickettsial infections in south-eastern Iran motivated this investigation to identify rickettsial species in ticks collected from hedgehogs to help assess their potential role in spreading tick-borne diseases. So, this study aimed to screen tick pools collected from synanthropic hedgehogs in southeastern Iran for Rickettsia spp. DNA and to perform presumptive species identification using partial gltA sequencing. Among 60 hedgehogs live-trapped and sampled in two cities (Zabol, Kerman), forty of the long-eared and five of Brandt's were tick-infested. We collected 68 ticks from 18 hedgehogs trapped in Zabol and 70 ticks from 27 hedgehogs trapped in Kerman. All collected ticks were adults and were morphologically identified as Rhipicephalus sanguineus s.l. or Rhipicephalus turanicus. Ticks collected from each individual hedgehog were pooled together and each pool consisted of ticks belonging to a single species collected from one individual hedgehog. Tick-pool DNA extracts were screened for Rickettsia spp. using a genus-level SYBR Green real-time PCR targeting the gltA gene. Screening-positive pools were confirmed by a TaqMan real-time PCR targeting the 16 S rRNA gene, and samples with Ct values < 31 were subjected to conventional PCR for amplification of an 834-bp gltA fragment. Species-level identification was performed based on partial gltA sequencing, BLAST analysis, and phylogenetic comparison. A total of 5 of 45 tick pools (11.1%) were positive for Rickettsia spp. DNA, including four Rhipicephalus sanguineus s.l. pools and one Rhipicephalus turanicus pool. Based on partial gltA sequencing, two positive pools were assigned as presumptive Rickettsia sibirica, two as presumptive Rickettsia rhipicephali, and one Rh. turanicus pool showed mixed detection of both species.The presence of Rickettsia spp. DNA in ticks collected from hedgehogs underscores the need for understanding of the potential involvement of synanthropic animals as reservoirs for tick-borne and other pathogens in different parts of Iran and surrounding areas.

Vector-borne diseases in dogs are an emerging problem worldwide due to their frequency, morbidity, and zoonotic relevance. Since there are no previous studies determining the frequency of Ehrlichia canis and Rickettsia rickettsii infection in three neighborhoods of the city of Chihuahua, Mexico, using molecular detection techniques, the objective of the present study was to detect, by nested polymerase chain reaction (PCR), a fragment of the gp36 gene of E. canis and the ompA gene of R. rickettsii in tick-infested dogs captured at the canine control center of the city of Chihuahua, and to phylogenetically analyze the genotypes present. Blood samples were collected from 123 tick-infested dogs. DNA was extracted from peripheral blood leukocytes and used in nested PCR protocols. The results showed a positivity frequency of 16.2% (20/123) for E. canis and 3.2% (4/123) for R. rickettsii. Six sequenced samples corresponded to E. canis and four to R. rickettsii. Phylogenetic analysis showed a close relationship with sequences previously described in the United States. This is the first molecular identification confirming E. canis and R. rickettsii infection in tick-infested dogs from some neighborhoods of the Chihuahua city, Mexico.

Zoonotic neglected tropical diseases (NTDs) remain a substantial but under-recognised source of human morbidity and economic concern in the Greater Mekong Subregion, particularly in settings characterised by close human-animal interaction. This article represents a narrative synthesis of zoonotic disease research conducted in Laos and Cambodia between 2000 and 2025. The review integrates published literature with findings from long-term surveillance programmes conducted by the authors and collaborating institutions in Laos, with comparative insights from Cambodia, to examine the presence, distribution, diversity, and drivers of zoonotic pathogens at the human-animal interface. Evidence demonstrates the endemic presence of a wide range of parasitic, bacterial, and viral zoonoses, including Taenia solium, Trichinella spp., Streptococcus suis, rickettsial infections, melioidosis, hepatitis E virus, and Japanese encephalitis virus. Some of these pathogens are sustained within smallholder livestock systems, informal slaughter, farming practises, food networks, and wet market environments, where limited diagnostic capacity and fragmented surveillance obscure true disease presence. Surveillance innovations, including abattoir-based sampling, cross-sectoral serological studies, environmental surveillance approaches, and molecular diagnostic tools, have improved pathogen detection but have also highlighted persistent structural and behavioural barriers to control. Socio-cultural practices, occupational exposure, wildlife trade, and economic dependencies reinforce transmission dynamics, indicating that biomedical interventions alone are insufficient. Instead, zoonotic disease persistence reflects the interaction of livestock production systems, environmental conditions, diagnostic limitations, and entrenched human behaviours. This review emphasises the need for integrated One Health approaches that combine strengthened surveillance, improved diagnostics, behavioural interventions, and regional collaboration. Addressing zoonotic NTDs in Laos and Cambodia requires coordinated strategies that account for both biological complexity and socio-economic context to achieve sustainable disease control and improved public health outcomes.

Zoonotic diseases are a primary threat to military readiness during deployments in the Asia-Pacific region. To characterize these risks, we conducted a multi-site, multi-year 'One Health' biosurveillance study during the Balikatan (BK) 2024 and 2025 exercises in the Philippines, sampling rodents, ectoparasites, and the environment at four key training locations on Luzon Island. A comprehensive biosurveillance study at four BK training sites revealed distinct, evolving, and site-specific zoonotic disease risks that require tailored health protection strategies. The risk is most acute at Clark Air Base, a critical dual-threat hotspot with an active circulation of several pathogenic strains of Leptospira in environment and rodents near the animal support facility and a direct threat from Rickettsia-positive chiggers. Other sites show escalating vector-borne disease threats including Fort Magsaysay Military Reservation transforming into a high-risk area for rickettsial diseases and Camp Aquino showing an emerging scrub typhus risk on top of its persistent Leptospira circulation. Even limited surveillance at Naval Operating Base Subic confirmed a mixed-threat environment where both Leptospira and rickettsial pathogens are co-circulating. Crucially, the detection of environmental Leptospira during the dry season is a key predictive indicator for a probable surge in transmission risk during the subsequent wet season, demanding proactive mitigation efforts.

We report the temporal and geographic distribution of ticks and tickborne Borrelia, Ehrlichia, and Rickettsia spp. bacteria in Texas, USA, 2014-2021, updating the previous 2008-2014 passive surveillance report. We identified 9 tick species and an overall prevalence of tested bacterial species of 26.0%, predominantly Rickettsia amblyommatis.

Rickettsia helvetica is a spotted fever group rickettsia associated mainly with Ixodes ricinus and increasingly detected in European ticks. We describe two tick-bite-associated human cases in Serbia in May 2025. A 65-year-old woman (Case 1) developed pruritic erythematous lesions after two adult female I. ricinus attachments acquired in the Valjevo area. Rickettsia spp. DNA was detected in capillary blood from both lesions, and sequencing of the PCR amplicons identified R. helvetica, while whole blood was PCR-negative and serology did not show reproducible seroconversion. An 8-year-old girl (Case 2) developed a pruritic scalp papule/crust and occipital/cervical lymphadenopathy after an adult female Haemaphysalis punctata attachment in Petrovaradin forest. Rickettsia spp. DNA was detected in lesion capillary blood and whole blood; sequencing identified both as R. helvetica. Clinical signs resolved after doxycycline. These observations support lesion-focused molecular testing and integrated human-tick-environment surveillance for underdiagnosed spotted fever group rickettsioses in Serbia.

Murine typhus, caused by Rickettsia typhi, is a flea-borne zoonosis that typically presents with fever, headache, myalgias, and rash. Central nervous system involvement is uncommon, and neuroimaging findings that mimic posterior reversible encephalopathy syndrome (PRES) are rarely reported. This case highlights a rare neuroinfectious presentation of murine typhus with PRES-like imaging findings in a young woman. A previously healthy woman in her 30s presented with persistent retro-orbital headaches, intermittent fevers, tremors, dysarthria, photophobia, myalgias, progressive weakness, and recurrent syncopal episodes. Initial computed tomography of the head demonstrated age-advanced microvascular ischemic changes versus possible PRES. Brain magnetic resonance imaging later revealed bilateral parietal-predominant fluid-attenuated inversion recovery (FLAIR) hyperintensities in the white matter, concerning for PRES. Cerebrospinal fluid (CSF) analysis was unremarkable, and extensive infectious and autoimmune evaluation was unrevealing. Despite nondiagnostic testing, persistent fevers and neurologic symptoms prompted empiric doxycycline therapy for suspected atypical infection. Within 48 hours, the patient experienced marked clinical improvement with resolution of fever, dysarthria, tremors, photophobia, and severe headache. Post-discharge serology showed a positive Rickettsia typhi IgM with a negative IgG. While these findings were consistent with possible early murine typhus, the absence of convalescent serologic testing limited definitive confirmation. Murine typhus is increasingly recognized as a cause of severe neurologic disease due to endothelial injury and systemic vasculitis. This case is notable for PRES-like neuroimaging abnormalities, normal CSF studies, and severe neurologic manifestations occurring in an otherwise healthy host without traditional risk factors for severe disease. The patient's rapid clinical improvement following doxycycline therapy was consistent with a rickettsial infection but was not diagnostic of murine typhus. This case highlights the importance of early empiric treatment when rickettsial disease is suspected while awaiting confirmatory testing. This case expands the recognized neurologic spectrum of murine typhus and emphasizes the importance of considering rickettsial infections in patients presenting with unexplained febrile neurologic syndromes and nonspecific MRI abnormalities, particularly in endemic regions.