How to differentiate pediatric enteroviral meningoencephalitis from scrub typhus meningoencephalitis: A single-center retrospective study from Yunnan Province, China.

Infectious encephalitis (IE) is a serious neurological condition that poses a major global health threat. This review summarizes emerging pathogens, particularly arboviruses, updated diagnostic strategies, and evolving treatment approaches, emphasizing ongoing gaps in diagnosis and management. Established arboviruses such as West Nile virus, Japanese encephalitis virus, Powassan virus, and Eastern Equine virus have regained attention due to their geographic expansion and the appearance of distinct genotypes. In parallel, increasing reports of encephalitis by newly emerging pathogens such as Oropouche virus and scrub typhus speak to the evolving nature of the epidemiology of IE. Advances in diagnostics, including multiplex PCR and metagenomic next-generation sequencing, have enhanced the breadth and accuracy of pathogen identification. As treatment options remain scarce, the role of immunomodulatory agents and novel antiviral molecules in the management of IE is actively being investigated. The emergence of novel and reemerging pathogens highlights the need for rapid, accurate diagnostics. Advanced molecular techniques and the identification of novel therapeutic targets have the potential to change the landscape of IE. However, strengthening surveillance and vaccination strategies, along with ongoing efforts in vaccine development, remain crucial for optimizing patient outcomes, increasing public health preparedness, and mitigating future outbreaks.

Host ecology shapes chigger mite parasitism on wild, captive, and domestic birds across Malaysia and Thailand

Scrub typhus, though common, gives rise rarely to severe complications such as infection-associated haemophagocytic lymphohistiocytosis (HLH) in children.

Tsutsugamushi fever is an infection caused by Orientia tsutsugamushi that is rarely diagnosed in Europe but endemic in several Asian countries and in Chile. Its clinical presentation is often nonspecific, ranging from fever, myalgia, lymphadenopathy, and amaculopapular rash to severe disease with multiorgan involvement. A34-year-old man presented with fever, myalgia, lymphadenopathy, and amaculopapular rash after returning from Thailand. Despite empiric antimicrobial therapy, his condition deteriorated rapidly, with respiratory failure, decreased vigilance, and hypotension. PCR testing from peripheral blood confirmed Orientia tsutsugamushi. Treatment with doxycycline, along with meropenem for hospital-acquired pneumonia, resulted in rapid clinical improvement. This case highlights the importance of considering tsutsugamushi fever in febrile travellers returning from endemic regions. Early presumptive or PCR-based diagnostics and initiation of effective therapy are crucial to prevent severe disease with multiorgan involvement and secondary complications.

Scrub typhus, an acute disease caused by Orientia tsutsugamushi and transmitted by larval chigger mites, is a representative autumn febrile illness in the Republic of Korea. We examined epidemiological characteristics underlying spatial heterogeneity in Busan Metropolitan City to inform region-specific prevention and control policies. We analyzed 1,645 confirmed and suspected scrub typhus cases reported in Busan from 2019 to 2023. Crude incidence rates and age-standardized incidence rates (ASIRs) per 100,000 population were calculated using the 2021 mid-year population. The chi-square test assessed associations between disease occurrence and exposure activities within the preceding 30 days. Correlation analyses examined the relationships of ASIR with environmental indicators, including per capita urban forest area, and epidemiological indicators, including prior infectious disease education. The overall mean ASIR in Busan was 8.35 per 100,000 population, below the national average. However, incidence was higher in peri-urban districts, including Gijang-gun (26.12/100,000) and Gangseo-gu (15.02/100,000), than in central urban districts such as Jung-gu (2.20/100,000). Higher incidence was observed among women and older adults (≥60 years). ASIR correlated strongly with per capita urban forest area (r=0.92; 95% confidence interval, 0.79-0.97; p<0.001). Regional differences were significant for agriculture/forestry, gardening, and general outdoor activities (p<0.001). Districts with higher incidence also displayed higher rates of infectious disease education, although this may reflect reverse causation. In Busan, scrub typhus incidence was concentrated in peri-urban districts. These findings support region-specific prevention strategies, evaluation of infectious disease education, enhanced mite surveillance, and practical protective measures during fieldwork.

Background and objectives Sepsis remains a leading cause of mortality among children worldwide. This study aimed to describe clinical profile, intensive care needs, outcome, and predictors of mortality among children with severe sepsis. Methods This secondary analysis of FerriPedS study was conducted in a tertiary pediatric intensive care units (PICU) in North India involving 115 children (3 months-12 yr) with severe sepsis. Data were collected regarding clinical details, laboratory investigations, organ dysfunction, intensive care needs, and outcome. Univariate and multinomial logistic regression analyses were used to determine predictors of mortality among severity score, organ dysfunction, serum ferritin, and PICU needs. Results The median (IQR) age was 3 (1-7) years, and common diagnoses were community acquired pneumonia (CAP) (n=45 39.1%), scrub typhus (n=16, 13.9%), and CNS infections (n=12,10.4%). Mortality was 27.8% (n=32). Non-survivors had significantly higher Pediatric Risk of Mortality-III (PRISM III) score, serum ferritin, and daily Pediatric logistic organ dysfunction-2 (PeLOD-2) score. Higher proportion of non-survivors had positive blood culture at admission, coagulopathy, hepatic dysfunction, shock, acute respiratory distress (ARDS), acute kidney injury (AKI), and multiple organ dysfunction score (MODS); and required invasive mechanical ventilation, vasoactive drugs, blood products, and RRT. On multinomial logistic regression analysis, PRISM-III, ARDS, and AKI were independent predictors of mortality. Interpretation and conclusions In children with severe sepsis, the common etiologies included CAP, scrub typhus, and CNS infections, and characterised by high mortality (27.8%). PRISM-III score, ARDS, and AKI were independent predictors of mortality.

Scrub typhus (ST) is an acute febrile illness caused by Orientia tsutsugamushi (Hayashi, 1920) that is transmitted to humans through the bite of infected chiggers. In recent years, ST has re-emerged as a public health concern in Malaysia. In 2024, more than 50 laboratory-confirmed human cases of ST were reported in Pahang. A collaborative investigation was undertaken on a subset of 26 cases to identify potential vector sources and animal hosts associated with O. tsutsugamushi transmission. Chigger-based sampling was conducted by trapping small mammals in suspected infection hotspots, including residential surroundings, frequently visited locations, and work areas of confirmed cases. A total of 95 small mammals were captured, of which 65.3% infested with chiggers (Chigger index, CI = 40.3). Overall, 3,831 on-host chiggers were collected and identified morphologically, with Leptotrombidium deliense (Walch, 1922) being the most frequently collected species (46.7%), followed by Ascoschoengastia indica (Hirst, 1915) (33.9%), Leptotrombidium spp. (18.4%), and Helenicula mutabilis (Gater, 1932) (1.0%). DNA was extracted from 188 pooled chigger samples (N = 3,450) as well as from blood and spleen tissues of captured animals, and screened for O. tsutsugamushi using nested PCR targeting the 56-kDa TSA gene. Notably, O. tsutsugamushi was detected in 13 (6.9%) chigger pools solely of L. deliense, and in 11 spleens and six blood samples. Phylogenetic analysis showed high nucleotide similarity (97-100%), with the Karp genotype predominating, followed by Gilliam, Kato, and TA763 genotypes. These findings confirm the presence of O. tsutsugamushi in vectors and animal hosts in Pahang, highlighting the region as a potential ST hotspot, and underscoring the need for continued monitoring and control efforts.

Zoonotic diseases are occurring more frequently in different parts of the world. In India, most outbreaks are reported by the Integrated Diseases Surveillance Programme (IDSP). The objective of this study was to find the trend of zoonotic diseases reported in the IDSP portal. Data were collected from the IDSP portal from January 2010 to December 2023. Data were collected regarding each outbreak's start date, the number of cases and the number of deaths. A total of 10 diseases were included in the study. From all reported outbreaks, a total of 1158 were reported for the selected zoonotic diseases. Japanese Encephalitis/Acute Encephalitis Syndrome (AES) was the most commonly reported outbreak. For anthrax, JE/AES, Crimean-Congo haemorrhagic fever, leptospirosis and scrub typhus, outbreaks and cases were reported throughout the year. However, most diseases were only reported during the rainy season (July-September). Although an increasing trend of the selected zoonotic diseases is reported in the current study, these data must be interpreted cautiously, considering the limitations of reporting. Activities should be planned based on burden estimation to prevent the morbidity and mortality associated with these diseases.

BackgroundScrub typhus and spotted fever are the two most common rickettsial infections in India. Both conditions differ, however, in terms of epidemiological risk, clinical presentation, and prognosis. We aimed to compare the clinical and laboratory characteristics of patients diagnosed with scrub typhus or spotted fever to identify disease indicators that are useful in low-resource endemic settings.MethodsWe conducted a retrospective cohort study among adults admitted with undifferentiated fever lasting 5–15 days at a tertiary care hospital in coastal Karnataka, India, between January 2017 and December 2023. Probable spotted fever and probable scrub typhus were diagnosed by single positive serology, using the Weil–Felix test and IgM ELISA, respectively. Patients with coinfection between the two study conditions or with any other confirmed pathogen were excluded from the analysis. Binary logistic regression was performed with spotted fever as the dependent variable and scrub typhus as the referent category.ResultsOf 1045 patients with undifferentiated fever, 94 met the study criteria for probable spotted fever and 643 for probable scrub typhus. Probable spotted fever was observed throughout the year, whereas probable scrub typhus showed a marked monsoon and post-monsoon predominance, from June to November. Rash (39.4% vs 11.0%, P < .001) and leucocytosis (46.8% vs 26.6%, P < .001) were significantly more frequent in probable spotted fever than in probable scrub typhus. In contrast, splenomegaly (21.3% vs 37.5%, P = .002), lymphadenopathy (2.1% vs 11.8%, P = .004), lung involvement (34.0% vs 62.2%, P < .001), and hypoalbuminemia (55.6% vs 75.7%, P < .001) were less frequent in probable spotted fever than in probable scrub typhus. In multivariable analysis with spotted fever as the outcome, rash (adjusted odds ratio [aOR], 5.69, P < .001) and leucocytosis (aOR, 3.67, P < .001) were independently associated with higher odds of probable spotted fever. In contrast, monsoon or post-monsoon presentation (aOR, 0.48, P = .006), splenomegaly (aOR, 0.45, P = .008), lymphadenopathy (aOR, 0.09, P = .002), lung involvement (aOR, 0.29, P < .001), and hypoalbuminemia (aOR, 0.45, P = .003) were associated with lower odds of probable spotted fever relative to probable scrub typhus. There was no significant difference in day-7 mortality between the two groups.ConclusionsProbable scrub typhus and probable spotted fever can be differentiated by a set of epidemiological, clinical, and first-line laboratory variables. These findings should improve the bedside diagnostic approach while awaiting further multicenter prospective validation.

Scrub typhus is a mite-borne rickettsial infection endemic in many parts of India and typically causes small-vessel vasculitis; large-vessel involvement is rare. We report a 52-year-old immunosuppressed man on long-term tofacitinib who presented with prolonged fever, weight loss, and systemic inflammation, and was found to have multiple pseudoaneurysms involving the abdominal aorta, carotid, and popliteal arteries, along with pulmonary nodules and necrotic lymphadenopathy. Extensive evaluation for tuberculosis, fungal infections, and bacterial endocarditis was negative, with no response to broad-spectrum antimicrobials or antitubercular therapy. Serology for scrub typhus was positive following identification of travel to an endemic area, and doxycycline led to rapid clinical and biochemical improvement. Selected pseudoaneurysms were managed surgically and endovascularly with good outcomes. This case highlights scrub typhus as a rare cause of large-vessel pseudoaneurysms in immunosuppressed patients in endemic regions.

Ectoparasite diversity and Orientia tsutsugamushi infection in rodent hosts from scrub typhus-endemic areas of the Western Himalayas, India.

Tsutsugamushi disease is an infectious disease caused by Orientia tsutsugamushi and transmitted by chiggers. The ancient classical form (summer onset) has almost disappeared, but the new form (spring and autumn onset) occurs in 300-500 cases annually. Symptoms include fever, rash, and bites. If the disease worsens, it can lead to meningoencephalitis, disseminated intravascular coagulation, and become fatal. Diagnosis involves confirming an increase in specific serum antibodies or detecting the gene in crusts. Prompt tetracycline treatment is important.

Scrub Typhus is a vector-borne infectious disease caused by Orientia tsutsugamushi, transmitted through infected chigger mite bites, and is widely prevalent in tropical and subtropical regions, particularly in the Asia-Pacific zone. Early and accurate diagnosis is critical, yet challenging due to overlapping symptoms with other febrile illnesses such as dengue, malaria, and typhoid. Traditional diagnostic methods relying on clinical observation and laboratory tests are often time-consuming and prone to misdiagnosis. This paper proposes a multimodal machine learning framework that combines clinical symptom data with skin lesion image analysis for scrub typhus classification. Clinical features including fever, headache, myalgia, eschar, chills, sweating, and vomiting are analyzed using Support Vector Classifier (SVC) and Random Forest algorithms. Concurrently, a Convolutional Neural Network (CNN) based on the ResNet-18 architecture is applied to detect eschar patterns in skin lesion images. Explainable AI techniques, specifically SHAP (SHapley Additive Explanations) for clinical feature importance and Grad-CAM++ for image region visualization, are incorporated to improve model interpretability. The multimodal fusion of both data modalities achieves an overall accuracy of 0.75, precision of 0.74, recall of 0.73, F1-score of 0.73, and ROC-AUC of 0.78, outperforming unimodal approaches and existing comparative methods. The proposed system demonstrates the effectiveness of combining heterogeneous data modalities with explainable AI for early and reliable Scrub Typhus detection.

Scrub typhus, caused by Orientia tsutsugamushi, is a re-emerging zoonotic infection endemic to the Asia-Pacific region including India. It presents with diverse and often nonspecific clinical manifestations, making diagnosis a challenge . We present three serologically (IgM ELISA) confirmed cases of scrub typhus from rural Tamil Nadu, India, that exhibited distinct neurological symptoms. Case 1: A 56-year-old male farmer with meningoencephalitis characterised by altered sensorium, neck rigidity, and papilloedema, who achieved complete recovery with doxycycline. Case 2: A 45-year-old woman with acute inflammatory myopathy, severe proximal muscle weakness, and elevated muscle enzymes, requiring combined doxycycline and steroid therapy for full recovery. Case 3: a 39-year-old female rice mill worker who developed bilateral moderately severe sensorineural hearing loss with vestibular symptoms, partially improving with doxycycline. These cases highlight the diverse neurological manifestations of scrub typhus beyond classical presentations, advocating for heightened clinical awareness to reduce morbidity from this re-emerging tropical disease.

Kawasaki disease (KD) is an acute medium‑vessel vasculitis and a leading cause of acquired heart disease in children. Scrub typhus may mimic KD or coexist, requiring prompt antibiotic therapy, while KD necessitates immunomodulatory treatment. Careful clinical evaluation, laboratory assessment, and echocardiography are essential for differentiation. A systematic, multidisciplinary approach improves diagnostic accuracy, optimizes management, and reduces cardiovascular complications. We report a 2‑year‑10‑month‑old boy who presented with high‑grade fever, generalized maculopapular rash, and bilateral non‑purulent conjunctival congestion. Based on clinical features consistent with KD, he was promptly treated with intravenous immunoglobulin and aspirin to reduce the risk of coronary artery complications, resulting in initial defervescence and clinical improvement. However, recurrence of fever during hospitalization necessitated further evaluation for alternative or concomitant etiologies. Subsequent laboratory investigations revealed positive serology for scrub typhus. Doxycycline therapy was initiated, leading to sustained defervescence and complete recovery. This case emphasizes the importance of early diagnosis and timely management of KD to prevent cardiac sequelae. It also highlights the need to consider coexisting tropical infections, particularly in an endemic region, in children with persistent or recrudescent fever despite appropriate initial immunomodulatory therapy.

Scrub typhus, caused by Orientia tsutsugamushi, affects over one million people annually in the Asia-Pacific region, with an in-hospital mortality rate of more than 30% among patients with severe disease. Early identification of patients at high risk of progression to multi-organ failure remains a major clinical challenge. Timely risk stratification to identify high-risk patients is essential to prevent poor clinical outcomes. This study identifies soluble programmed death-ligand 1 as a potential early biomarker that distinguishes patients at risk of developing severe disease within the first week of hospitalization.

Background: Thrombocytopenia, which raises the risk of bleeding and indicates the severity of the illness, frequently complicates acute febrile illness (AFI), a leading cause of paediatric admissions. Infections including dengue, malaria, typhoid, and scrub typhus frequently produce this dual presentation, although autoimmune diseases, hematological abnormalities, or drug-induced reasons can also cause it. Management is difficult because to overlapping symptoms and poor diagnostics, particularly in endemic areas. For the purpose of directing treatment and averting complications, early detection of thrombocytopenia in children with fever is essential. To enhance diagnostic techniques, treatment plans, and medical responses in high-burden environments, targeted study on clinical profiles and outcomes is required. Aim and Objectives: This study aims to evaluate the clinical profile and outcomes of children aged 1 month to 18 years admitted with acute febrile illness and thrombocytopenia at a tertiary care center in Puducherry. The objectives are to describe clinical presentations, identify infectious and non-infectious etiologies, and correlate the severity of thrombocytopenia with disease outcomes. Materials and Methods: In this cross-sectional study, 266 children with acute febrile illness and thrombocytopenia, ages 1 month to 18 years, were enrolled in the paediatrics department of a tertiary care hospital in Puducherry between June 2023 and June 2024. A thorough history, clinical examination, and pertinent tests (CBC, peripheral smear, renal/liver function tests, malaria RDT, dengue serology, scrub typhus IgM, Widal, blood cultures, chest X-ray, MRI for probable encephalitis) were carried out following informed consent and assent. Transfusions were administered for severe thrombocytopenia or bleeding, and platelet counts were tracked until they returned to normal. Malaria, dengue, scrub typhus, enteric fever, leukemia/ITP, septicemia, viral encephalitis, and undetected fever were among the diagnoses. Results and Discussion: The clinical profile and results of paediatric patients with acute fever and thrombocytopenia are highlighted in this study. The most common causes were scrub typhus and dengue fever, highlighting the significance of regional epidemiology in directing diagnosis. The majority of patients had minor thrombocytopenia, a good prognosis, a high rate of recovery, and little need for transfusions. Severe thrombocytopenia, however, was linked to extended hospital admissions and sporadic organ malfunction, highlighting the necessity of continuous observation and critical treatment in these situations. In endemic areas, serological tests—specifically, dengue IgM and scrub typhus IgM— proved useful in making diagnoses. The significance of a thorough organ function assessment was highlighted by anomalies in severe instances, even when liver and renal functions were generally conserved. Overall, from the results it is clear that it is difficult to treat paediatric febrile thrombocytopenia and emphasize the need for immediate therapies, systematic diagnostic techniques, and additional research into risk stratification models and new biomarkers to enhance outcomes.

Congenital scrub typhus is a rare form of Orientia tsutsugamushi infection in neonates. Typical neonatal manifestations include fever, thrombocytopenia and hepatosplenomegaly; however, presentation in the form of non-immune hydrops fetalis (NIHF) is uncommon and has not been reported previously in literature. We report a case of vertically transmitted scrub typhus in a preterm neonate who presented with hydrops fetalis at birth. The diagnosis was established using molecular testing, and timely initiation of appropriate antimicrobial therapy resulted in complete recovery. This case and the accompanying literature review expand the clinical spectrum of congenital scrub typhus and highlight the importance of considering it as a treatable infectious cause of NIHF in endemic regions.

Orientia tsutsugamushi, the causative agent of scrub typhus, can be isolated in Vero or L929 cells and has a small genome (2-2.5 Mb). However, genome assembly is challenging due to the presence of host DNA contamination and a high proportion of repeat regions (up to 51%). Current global data includes 11 fully annotated genomes, with none from India. Here, we present the first whole-genome sequences of O. tsutsugamushi strains circulating within India. Five O. tsutsugamushi strains were cultured in Vero cells and confirmed by 47 kDa real-time PCR. Genomic DNA was extracted after removal of host DNA and sequencing libraries were prepared. Whole-genome sequencing was performed using the PacBio Sequel II system in CCS/HiFi mode. The raw reads were assembled using Flye, and genome completeness was assessed with QUAST and BUSCO. Annotation was performed using the NCBI PGAP pipeline and comparative genome analysis by Roary. Phylogenetic analyses were performed using both the complete 56-kDa gene and whole-genome sequences to assess genetic relationships among O. tsutsugamushi strains. We report five complete (circular) genomes of O. tsutsugamushi. Genome sizes range from 2.1 to 2.4 Mb. The total number of predicted genes falls between 2,379 and 2,715, with an average of 1,824 coding genes and 613 pseudogenes. Repeat regions ranged from 55% to 59%, corresponding to total lengths of approximately 1.2-1.44 Mb. All five genomes have been submitted to NCBI GenBank (Accession Numbers: CP166954-58). Phylogenetic analysis based on the full-length 56 kDa gene revealed that two strains belong to the Karp genogroup, two to Kato, and one to TA763. This study presents the first whole-genome sequencing data of O. tsutsugamushi from India. Comprehensive phylogenomic studies, particularly to elucidate evolutionary dynamics and potential recombination events, will provide further information.