Clinical features and risk factors for death in acute undifferentiated fever: A prospective observational study in rural community hospitals in six states of India

BACKGROUND

Acute undifferentiated fever (AUF) ranges from self-limiting illness to life-threatening infections, such as sepsis, malaria, dengue, leptospirosis and rickettsioses. Similar clinical presentation challenges the clinical management. This study describes risk factors for death in patients hospitalized with AUF in India.

METHODS

Patients aged ≥5 y admitted with fever for 2-14 d without localizing signs were included in a prospective observational study at seven hospitals in India during 2011-2012. Predictors identified by univariate analysis were analyzed by multivariate logistic regression for survival analysis.

RESULTS

Mortality was 2.4% (37/1521) and 46.9% (15/32) died within 2 d. History of heart disease (p=0.013), steroid use (p=0.011), altered consciousness (p<0.0001), bleeding (p<0.0001), oliguria (p=0.020) and breathlessness (p=0.015) were predictors of death, as were reduced Glasgow coma score (p=0.005), low urinary output (p=0.004), abnormal breathing (p=0.006), abdominal tenderness (p=0.023), leucocytosis (p<0.0001) and thrombocytopenia (p=0.001) at admission. Etiology was identified in 48.6% (18/37) of fatal cases.

CONCLUSIONS

Bleeding, cerebral dysfunction, respiratory failure and oliguria at admission, suggestive of severe organ failure secondary to systemic infection, were predictors of death. Almost half of the patients who died, died shortly after admission, which, together with organ failure, suggests that delay in hospitalization and, consequently, delayed treatment, contribute to death from AUF.

Molecular Detection of Candidatus Orientia chuto in Wildlife, Saudi Arabia

Scrub typhus is a zoonosis caused by 3 species of Orientia bacteria, including Candidatus Orientia chuto. This species is known only from a human case in Dubai and infections in wildlife in Kenya. We report molecular detection of Candidatus O. chuto in 2 wild rodent species from Saudi Arabia.

Acute Onset Postpartum Pleural Effusion: A Near-Miss Maternal Case Due to Scrub Typhus Infection

A 32-year-old puerperal patient developed acute onset breathlessness and fever on the third postoperative day. On evaluation, the patient was diagnosed to have scrub typhus pneumonia without any characteristic eschar. The condition was associated with pleural effusion, and it was drained. Azithromycin was used as the drug of choice due to the peripartum status of this patient. The patient improved due to early detection and multidisciplinary timely care. The safe outcome of this near-miss case suggests that fever profile workup, especially in scrub typhus endemic areas, should include scrub typhus testing even if classical signs are absent in the peripartum period.

Serologic Evidence of Orientia Infection among Rural Population, Cauca Department, Colombia

We assessed serum samples collected in Cauca Department, Colombia, from 486 persons for Orientia seroreactivity. Overall, 13.8% showed reactive IgG by indirect immunofluorescence antibody assay and ELISA. Of those samples, 30% (20/67) were confirmed to be positive by Western blot, showing >1 reactive band to Orientia 56-kD or 47-kD antigens.

Concurrent Infection with SARS-CoV-2 and Orientia tsutsugamushi during the COVID-19 Pandemic in the Maldives

The COVID-19 pandemic was the worst public-health crisis in recent history. The impact of the pandemic in tropical regions was further complicated by other endemic tropical diseases, which can cause concurrent infections along with COVID-19. Here, we describe the clinical course of a patient with concurrent COVID-19 and scrub typhus infection. The patient's de-identified clinical data were retrieved retrospectively. The patient had progressive breathlessness at the time of presentation and was hospitalized for COVID-19. Respiratory examination revealed dyspnea, tachypnea, and coarse crepitations bilaterally over the entire lung field. Oxygenation was impaired, and a PaO2/FiO2 ratio of 229 suggested acute respiratory distress syndrome. Laboratory tests indicated leukocytosis, thrombocytopenia, ferritinemia, hypoalbuminemia, and transaminitis. Upon revaluation for persistent fever, physical examination revealed an eschar in the right antecubital fossa. Serology further confirmed scrub typhus, with IgM and IgG antibody positivity. A remarkable clinical recovery was achieved with doxycycline. The COVID-19 pandemic might have masked endemic tropical diseases. Clinicians working in endemic regions must always consider common tropical diseases that may present as a co-infection, as in our case. Travel and exposure history are critical guides for narrowing down a differential diagnosis. Early diagnosis and treatment can prevent complications.

Seroprevalence of scrub typhus and other rickettsial diseases among the household rodents of Mizoram, North-East India

In the last decade, scrub typhus, a zoonotic disease has emerged as a major health concern in Mizoram, a North-East Indian state that shares international borders with Myanmar and Bangladesh. Mizoram is a biodiversity hotspot and >85% of the state is under forest cover, which provides an ideal ecological niche for the rodents and mites to transmit scrub typhus and other rickettsial infections. Using the Weil-Felix test, a serosurvey of household rodents from 41 villages spread across all the 11 districts in Mizoram was undertaken to gather important insights on their role in disease transmission. Furthermore, the chigger and flea indexes were calculated from the captured rodents. The 163 rodents captured belonged to five species; the highest numbers were from Rattus tanezumi (87), followed by Rattus rattus (41), Mus musculus (17), Suncus murinus (16), and Bandicota bengalensis (2). The rickettsial seropositivity of the captured rodents was 66.26% (108 out of 163 were positive). Among the 163 rodents, sera of 75 (46.01%), 61 (37.42%), and 73 (44.78%) were reactive to OXK, OX19, and OX2 antigens, respectively. The chigger and flea index were 17.92 and 0.16, respectively. Overall, the study has given important insights into the risk of multiple rickettsial infections that household rodents could transmit in Mizoram. These findings indicate the need for the urgent implementation of effective rodent control strategies in Mizoram.

Scrub typhus seroprevalence from an eastern state of India: findings from the state-wide serosurvey

BACKGROUND

Scrub typhus is a mite-borne infectious disease caused primarily by the obligate intracellular bacteria Orientia tsutsugamushi, which is transmitted by chigger mites. The objective of this study was to determine the prevalence of scrub typhus among adults in Odisha, an eastern state of India.

METHODS

A descriptive cross-sectional study was conducted to analyse 1840 serum samples from five districts (Khordha, Cuttack, Ganjam, Malkangiri and Sundargarh) of Odisha collected during 2020-2021. Both immunoglobulin G (IgG) and IgM antibodies against scrub typhus were tested using commercial enzyme-linked immunosorbent assay kits. Point estimates of the 95% confidence interval and adjusted odds ratio were calculated.

RESULTS

Of 1840 participants, the prevalence of IgG positivity was 1034 (56.19%) and that of IgM was 523 (28.42%). The majority of participants were in the 18-45 y age group (53.7%). Cuttack had the highest IgG positivity (64.54%) and Malkangiri had the lowest (29.32%). The highest and lowest positivity for IgM were found in Malkangiri (40.84%) and Cuttack (25.30%), respectively.

CONCLUSIONS

With an increasing number of infections detected in the state, scrub typhus is emerging as a public health threat. Increasing awareness among the general public and healthcare professionals through health education campaigns regarding scrub typhus is essential. Early detection of the disease through the establishment of a laboratory surveillance system is required to control the transmission of scrub typhus.

Monitoring Weil-Felix test in epidemic retinitis

Purpose

The objective was to study the positivity of the Weil-Felix test (WFT) in epidemic retinitis (ER) during the course of the disease.

Methods

This is a retrospective, observational case series of patients diagnosed with ER and presented to a tertiary eye care hospital in south India. Patients with positive WFT at the presentation, and who underwent a follow-up WFT during or after the resolution of ER were studied from September 2019 to March 2022. Patient's demographics, timings of clinical presentation and resolution, and investigation details with a special focus on WFT positivity and its duration were noted.

Results

Sixteen patients were studied. Patients presented after 5 weeks of the fever (range: 2-12 weeks, median: 4). After 1-2 months, WFT was still positive in eight patients (50%). Only in one patient titers increased after 1 month, while in others, the titers decreased (n = 11) or remained the same (n = 4). Repeated tests in those patients (n = 6) after 3-4 months turned negative. Resolution of ER was seen at 1.35 months (range: 1-3 months) after the presentation. The mean duration for WFT to turn negative was 2 months from the presentation (range: 1-4 months) or 3.2 months of the fever (range: 1.5-6 months).

Conclusion

In contrast to the reported physician's observation of increasing titers of WFT after rickettsial fever, ophthalmologists may observe decreasing WFT titers in ER. The clinical resolution of ER may precede the normalization of WFT. Follow-up WFT titers should be studied in larger series in confirmed cases of rickettsial-ER to validate the affordable and readily available WFT in India.

Evaluation of Scrub Typhus Surveillance, Alwar District, Rajasthan, India, July-August 2020

Introduction

Scrub typhus is one of the most underreported and fatal illnesses accounting for 23% of all febrile illness. Rajasthan reported cases during 2018-2019 in state reporting system but did not report any case to central Integrated Disease Surveillance Programme (IDSP) unit. We evaluated the Scrub typhus surveillance system in Alwar district, Rajasthan, with the objective of describing and evaluating the system and providing evidence-based recommendations to identify gaps.

Material and Methods

In cross-sectional study, we reviewed records and conducted key informant interviews at district- and block-level health facilities. Using US Centers for Disease Control guidelines, we evaluated the system by framing indicators for selected attributes for a defined reference period. Overall performance was ranked as outstanding (90-100%), excellent (80-89%), very good (70-79%), good (60-69%), and poor (<60%).

Results

Line list of confirmed cases was sent from district to block level for additional active case search (ACS) to implement control measures. We conducted 26 key informant interviews and reviewed records and calculated simplicity as 79%, flexibility 100%, data quality 46%, acceptability 92%, representativeness 48%, timeliness 43%, and stability 79%.

Conclusions

Epidemiological surveillance (active and passive) is a core intervention under scrub typhus surveillance system. Lab reports were incompletely uploaded on IDSP portal. Surveillance reports should be updated after each ACS. Reporting format under IDSP should be uploaded timely, and lab reports from state should be sent within 48 hours of diagnosis so that case investigation is not delayed.

Impacts of meteorological factors on the risk of scrub typhus in China, from 2006 to 2020: A multicenter retrospective study

Scrub typhus is emerging as a global public health threat owing to its increased prevalence and remarkable geographic expansion. However, it remains a neglected disease, and possible influences of meteorological factors on its risk are poorly understood. We conducted the largest-scale research to assess the impact of meteorological factors on scrub typhus in China. Weekly data on scrub typhus cases and meteorological factors were collected across 59 prefecture-level administrative regions from 2006 to 2020. First, we divided these regions into 3 regions and analyzed the epidemiological characteristics of scrub typhus. We then applied the distributed lag nonlinear model, combined with multivariate meta-analysis, to examine the associations between meteorological factors and scrub typhus incidence at the total and regional levels. Subsequently, we identified the critical meteorological predictors of scrub typhus incidence and extracted climate risk windows. We observed distinct epidemiological characteristics across regions, featuring obvious clustering in the East and Southwest with more even distribution and longer epidemic duration in the South. The mean temperature and relative humidity had profound effects on scrub typhus with initial-elevated-descendent patterns. Weather conditions of weekly mean temperatures of 25-33°C and weekly relative humidity of 60-95% were risk windows for scrub typhus. Additionally, the heavy rainfall was associated with sharp increase in scrub typhus incidence. We identified specific climatic signals to detect the epidemic of scrub typhus, which were easily monitored to generalize. Regional heterogeneity should be considered for targeted monitoring and disease control strategies.

A Use of 56-kDa Recombinant Protein of Orientia tsutsugamushi Karp Serotype in Serodiagnosis of Scrub Typhus by Enzyme-Linked Immunosorbent Assay in Thais

Scrub typhus is a mite-borne disease caused by a Gram-negative obligately intracellular bacillus, Orientia tsutsugamushi. The disease is endemic in the Asia-Australia-Pacific region, including Thailand. Scrub typhus generally manifests as acute undifferentiated febrile fever along with myalgia, rash, and lymphadenopathy. An eschar can be a valuable diagnostic clue, but this skin lesion may be missed in some patients. The disease symptoms resemble those of other febrile illnesses such as leptospirosis, typhoid, murine typhus, malaria, and dengue fever, making a laboratory diagnosis necessary for the definitive diagnosis. In this study, we expressed a recombinant protein derived from 56-kDa type-specific antigen of O. tsutsugamushi Karp serotype and tested its ability to detect and differentiate scrub typhus infection. IgM and IgG antibodies were determined in sera from scrub typhus (n = 92) and other febrile illness patients (murine typhus (n = 25), melioidosis (n = 36), leptospirosis (n = 42), and dengue (n = 35)) from Thailand. Sensitivities of 87.0% and 59.8% with a specified assay cut-off were obtained for IgM and IgG indirect ELISAs, respectively, with a specificity of 100% in both tests. The sensitivity was increased to 95.7% when a combination of IgM and IgG ELISAs results was considered. Our study suggested a potential of the 56-kDa recombinant protein for further development and evaluation for use in scrub typhus serodiagnosis.

Orientia tsutsugamushi OtDUB Is Expressed and Interacts with Adaptor Protein Complexes during Infection

Orientia tsutsugamushi is an etiologic agent of scrub typhus, a globally emerging rickettsiosis that can be fatal. The bacterium's obligate intracellular lifestyle requires its interaction with host eukaryotic cellular pathways. The proteins it employs to do so and their functions during infection are understudied. Recombinant versions of the recently characterized O. tsutsugamushi deubiquitylase (OtDUB) exhibit high-affinity ubiquitin binding, mediate guanine nucleotide exchange to activate Rho GTPases, bind clathrin adaptor protein complexes 1 and 2, and bind the phospholipid phosphatidylserine. Whether OtDUB is expressed and its function during O. tsutsugamushi infection have yet to be explored. Here, OtDUB expression, location, and interactome during infection were examined. O. tsutsugamushi transcriptionally and translationally expresses OtDUB throughout infection of epithelial, monocytic, and endothelial cells. Results from structured illumination microscopy, surface trypsinization of intact bacteria, and acetic acid extraction of non-integral membrane proteins indicate that OtDUB peripherally associates with the O. tsutsugamushi cell wall and is at least partially present on the bacterial surface. Analyses of the proteins with which OtDUB associates during infection revealed several known O. tsutsugamushi cell wall proteins and others. It also forms an interactome with adapter protein complex 2 and other endosomal membrane traffic regulators. This study documents the first interactors of OtDUB during O. tsutsugamushi infection and establishes a strong link between OtDUB and the host endocytic pathway.

Two possible etiologies of Guillain-Barré syndrome: mRNA-1273 (Moderna) vaccination and scrub typhus: A case report

RATIONALE

Guillain-Barré syndrome (GBS) is an acute inflammatory polyneuropathy related to infection with bacteria or virus and vaccination. Cases of GBS after coronavirus infection-19 (COVID-19) vaccination have been reported. However, cases of GBS after inoculation with mRNA-based COVID-19 vaccines, especially mRNA-1273, have rarely been reported compared to after inoculation with adenovirus vector-based COVID-19 vaccines. On 1 hand, GBS occurring after scrub typhus is often reported, but the exact pathological mechanism has not been elucidated. We report the case of a patient with GBS after inoculation with mRNA-1273 COVID-19 vaccine and scrub typhus.

PATIENT CONCERNS

A 47-year-old man received COVID-19 vaccination 4 weeks before admission. He had a fever, rash and general weakness 1 day after vaccination. After 3 weeks, the muscle strength of the extremities deteriorated to the extent that walking was impossible.

DIAGNOSIS, INTERVENTIONS, AND OUTCOMES

The patient developed quadriplegia with areflexia, axonal-type sensorimotor polyneuropathy was confirmed by nerve conduction study. The patient was diagnosed as GBS. Scrub typhus was also diagnosed as eschar was observed in the chest area and the serologic test of anti-R-tsutsugamushi antibody showed a strongly positive result. The patient received treatment with intravenous immunoglobulin at 0.4 g/kg daily for 5 days. Mechanical ventilation was applied during the intensive care unit. He was treated for scrub typhus simultaneously. Six months after the onset of the disease, the patient showed improvement to the point where he could work and exercise alone.

LESSONS

When GBS is suspected, early evaluation and treatment can lead to favorable outcomes. Considering that cases of GBS after COVID-19 vaccination have been reported, it is important to conduct early evaluation and management of patients with muscle weakness after COVID-19 vaccination to ensure early detection of GBS. And even if fever and rash are side effects that can occur frequently after vaccination, it is necessary to consider other diseases in addition to the side effects of the vaccine. This is to prevent delay in diagnosis and treatment of other diseases.

Disseminated Intravascular Coagulation Manifesting as Diffuse Alveolar Hemorrhage in a Scrub Typhus Patient: A Rarely Thought of Complication

Scrub typhus is a common cause of an acute, unexplained febrile illness. Without proper treatment, it can lead to life-threatening complications and even death. We present the case of a 16-year-old girl who presented with complaints of fever with reddish spots all over her body for 10 days and breathing difficulty for three days. She had an episode of gum bleeding just prior to admission and two episodes of hemoptysis after admission. She had severe thrombocytopenia, a low serum fibrinogen level, raised D-dimer levels, a raised activated partial thromboplastin time as well as a raised prothrombin time, and an international normalized ratio. Her chest radiograph showed diffuse bilateral interstitial infiltrates. A diagnosis of disseminated intravascular coagulation and diffuse alveolar hemorrhage secondary to possible hematological malignancy or vector-borne infectious disease was made. She was treated with intravenous doxycycline and broad-spectrum antibiotics, along with other supportive measures. Bone marrow aspiration and biopsy showed normal trilineage differentiation, normal erythropoiesis, myelopoiesis, and megakaryopoiesis. Finally, a positive immunoglobulin M (IgM) antibody for scrub typhus clinched the diagnosis. Her condition improved over the next week, and she was discharged with the advice to continue oral doxycycline for a week. This case highlights one of the rare complications of scrub typhus, disseminated intravascular coagulation, and the importance of timely initiation of treatment in such patients.

Hemophagocytic Lymphohistiocytosis secondary to Rickettsial infection: A case report

Hemophagocytic Lymphohistiocytosis (HLH) is a rare life-threatening condition characterized by widespread activation of the immune system leading to tissue damage all over the body. It is divided into primary HLH due to inborn error in lymphocytes, T cells, and macrophages and secondary HLH which is mostly due to infections, systemic connective tissue diseases, and lymphoid malignancies. Here, we report a 34-year-old man with a history of high-grade fever, chills, and rigor, eschar, splenomegaly with the laboratory findings of thrombocytopenia, hypochromic RBCs with anisocytosis and basophilic stippling, elevated transaminases, and a positive Weil Felix test along with positive PCR results for Orientia tsutsugamushi and the presence of IgG and IgM antibodies. A detailed workup was done to rule out other etiology for fever. Diagnosis of HLH secondary to Rickettsia infection was made with a thorough history, clinical evaluation, and a variety of investigations. The patient was treated with Doxycycline, Ciprofloxacin, Etoposide, and Dexamethasone but unfortunately, the patient died during treatment due to multiorgan failure. Patients with scrub typhus typically respond well to therapy; therefore, early detection and antibiotic treatment can help avoid serious complications. Scrub typhus with the hemophagocytic syndrome can result in DIC and multiorgan failure. Despite its rarity, scrub typhus may be lethal; as a result, practitioners must be aware of the necessity of detecting and treating suspected cases as soon as possible. We learned that a systematic diagnostic approach, use of diagnostic criteria, and prompt treatment are very crucial in this disease.

A potential tool for predicting epidemic trends and outbreaks of scrub typhus based on Internet search big data analysis in Yunnan Province, China

Introduction

Scrub typhus, caused by Orientia tsutsugamushi, is a neglected tropical disease. The southern part of China is considered an important epidemic and conserved area of scrub typhus. Although a surveillance system has been established, the surveillance of scrub typhus is typically delayed or incomplete and cannot predict trends in morbidity. Internet search data intuitively expose the public's attention to certain diseases when used in the public health area, thus reflecting the prevalence of the diseases.

Methods

In this study, based on the Internet search big data and historical scrub typhus incidence data in Yunnan Province of China, the autoregressive integrated moving average (ARIMA) model and ARIMA with external variables (ARIMAX) model were constructed and compared to predict the scrub typhus incidence.

Results

The results showed that the ARIMAX model produced a better outcome than the ARIMA model evaluated by various indexes and comparisons with the actual data.

Conclusions

The study demonstrates that Internet search big data can enhance the traditional surveillance system in monitoring and predicting the prevalence of scrub typhus and provides a potential tool for monitoring epidemic trends of scrub typhus and early warning of its outbreaks.

Climate drives the spatiotemporal dynamics of scrub typhus in China

Scrub typhus is a climate-sensitive and life-threatening vector-borne disease that poses a growing public health threat. Although the climate-epidemic associations of many vector-borne diseases have been studied for decades, the impacts of climate on scrub typhus remain poorly understood, especially in the context of global warming. Here we incorporate Chinese national surveillance data on scrub typhus from 2010 to 2019 into a climate-driven generalized additive mixed model to explain the spatiotemporal dynamics of this disease and predict how it may be affected by climate change under various representative concentration pathways (RCPs) for three future time periods (the 2030s, 2050s, and 2080s). Our results demonstrate that temperature, precipitation, and relative humidity play key roles in driving the seasonal epidemic of scrub typhus in mainland China with a 2-month lag. Our findings show that the change of projected spatiotemporal dynamics of scrub typhus will be heterogeneous and will depend on specific combinations of regional climate conditions in future climate scenarios. Our results contribute to a better understanding of spatiotemporal dynamics of scrub typhus, which can help public health authorities refine their prevention and control measures to reduce the risks resulting from climate change.

How meteorological factors impacting on scrub typhus incidences in the main epidemic areas of 10 provinces, China, 2006-2018

Scrub typhus, caused by Orientia tsutsugamushi, is a serious public health problem in the Asia-Pacific region, threatening the health of more than one billion people. China is one of the countries with the most serious disease burden of scrub typhus. Previous epidemiological evidence indicated that meteorological factors may affect the incidence of scrub typhus, but there was limited evidence for the correlation between local natural environment factors dominated by meteorological factors and scrub typhus. This study aimed to evaluate the correlation between monthly scrub typhus incidence and meteorological factors in areas with high scrub typhus prevalence using a distributed lag non-linear model (DLNM). The monthly data on scrub typhus cases in ten provinces from 2006 to 2018 and meteorological parameters were obtained from the Public Health Science Data Center and the National Meteorological Data Sharing Center. The results of the single-variable and multiple-variable models showed a non-linear relationship between incidence and meteorological factors of mean temperature (Tmean), rainfall (RF), sunshine hours (SH), and relative humidity (RH). Taking the median of meteorological factors as the reference value, the relative risks (RRs) of monthly Tmean at 0°C, RH at 46%, and RF at 800 mm were most significant, with RRs of 2.28 (95% CI: 0.95-5.43), 1.71 (95% CI: 1.39-2.09), and 3.33 (95% CI: 1.89-5.86). In conclusion, relatively high temperature, high humidity, and favorable rainfall were associated with an increased risk of scrub typhus.

Cerebral Venous Sinus Thrombosis Following Scrub Typhus Infection: A Case Report and a Review of the Literature

Neurological manifestations of scrub typhus, a re-emerging infectious disease of tropic/subtropics caused by Orientia tsutsugamushi infection, have been ever-evolving. Several central nervous system infections have been acknowledged for the development of cerebral venous sinus thrombosis (CVT). Nevertheless, CVT has been a rarely described addendum to the ever-evolving "neuro-scrub" spectrum. Proposed pathogenesis for the development of CVT is disseminated endotheliitis resulting in the triad of venous stasis (due to raised intracranial pressure), cerebral vasculopathy (endothelial damage), and capillary perivasculitis (endothelial damage and resultant hypercoagulable state generated by inflammatory mediators). We herein report a case of a previously healthy young female from the Indian subcontinent who was diagnosed with CVT, following scrub typhus. She responded well to conventional therapy with antibiotics and anticoagulants. CVT is amid the few completely reversible neurological catastrophes if diagnosed and treated early. Again, scrub typhus infection is treated with commonly available and extremely "affordable" antibiotics therapy. Hence, the authors propose that all cases of acute febrile illness with neurological manifestations from scrub-typhus endemic zones (like several parts of India) should be tested for the presence of Orientia tsutsugamushi infection and treated accordingly.

Orientia tsutsugamushi in Chiggers and Small Mammals in Laos

Background: Scrub typhus is a leading cause of febrile illness in Laos and accounts for a high burden of disease. There have been no previous studies on the causative agent, Orientia tsutsugamushi, in vector mites ("chiggers") or their small mammal hosts in Laos. Materials and Methods: Small mammals and free-living chiggers were trapped in districts of Vientiane Province and Capital. Tissues were tested for O. tsutsugamushi by PCR and serum for IgG to O. tsutsugamushi by immunofluorescence assays (IFAs). Chiggers removed from small mammals and collected in their free-living stage using black plates were identified and tested for O. tsutsugamushi by PCR. Results: Over an 18-month period, 131 small mammals of 14 species were collected in 5 districts. Seventy-eight of 131 small mammals were infested with chiggers, but all tissues were O. tsutsugamushi PCR negative. Eighteen species of chigger were identified and 1,609 were tested by PCR. A single pool of chiggers tested O. tsutsugamushi positive. Sera from 52 small mammals were tested by IFA, with 16 testing positive. Conclusions: These are the first molecular and serological data on O. tsutsugamushi in chiggers and small mammals in Laos. Further studies are needed to better understand the key vector species and ecology of scrub typhus in areas with high disease incidence in Laos.

Rapid Recovery of Acute Respiratory Distress Syndrome in Scrub Typhus, With Pulse Methylprednisolone and Therapeutic Plasma Exchange

Acute respiratory distress syndrome (ARDS) is an atypical presentation of scrub typhus infection with associated high morbidity and mortality compared to uncomplicated scrub typhus infection. Here we report an otherwise healthy 41-year-old female patient admitted with moderate ARDS secondary to scrub typhus infection who gained comparatively rapid recovery within 72 hours following intravenous methylprednisolone pulse (MPP) therapy with therapeutic plasma exchange (TPE), suggesting a beneficial role of MPP and TPE in the treatment of ARDS secondary to scrub typhus infection. To our knowledge, this is the first case report regarding the use of MPP therapy and TPE in a patient with ARDS due to scrub typhus infection.

Recent Threat of Scrub Typhus in India: A Narrative Review

Scrub typhus is an endemic illness transmitted by vectors and induced by bacteria. It is the most common and severe rickettsial disease. There are many more cases every year with a significant case fatality rate. Despite being a serious public health threat in India, it is uncertain how widespread and burdensome scrub typhus is. The scarcity of statistical information and pertinent health records on scrub typhus in the outbreak region demonstrates that there is still a significant knowledge gap about this neglected illness. Clinical manifestations of this illness include kidney failure, disability, and severe kidney failure. Undifferentiated symptoms, late diagnosis, and treatment failure are all responsible for deaths. Knowing about this disease is important from a public health point of view due to difficulties in specific diagnosis and a shortage of laboratory services in so many places. India is known to have scrub typhus cases, and doctors should be aware of this potentially dangerous but easily curable illness. The disease is highly difficult to identify clinically from other acute afebrile infections due to common symptoms and a paucity of the lesion in the Indian population. The mainstay of diagnosis is antibody-based serological testing. Within the first week of symptoms, scrub typhus can be diagnosed using molecular and serological tests. Our objective is to identify how severe scrub typhus is in India and to investigate the current epidemiology, etiology, complications, management, and treatment of the disease in both long-established endemic regions and new infection foci.

Habitat and Season Drive Chigger Mite Diversity and Abundance on Small Mammals in Peninsular Malaysia

Chigger mites are vectors of the bacterial disease scrub typhus, caused by Orientia spp. The bacterium is vertically transmitted in the vector and horizontally transmitted to terrestrial vertebrates (primarily wild small mammals), with humans as incidental hosts. Previous studies have shown that the size of the chigger populations is correlated with the density of small mammals in scrub typhus-endemic regions. Here, we explore interactions between the small mammals and chiggers in two oil palm plantations located in the Perak and Johor states of Peninsular Malaysia. The location in Perak also contained an aboriginal (Orang Asli) settlement. A ~5% sub-sample from 40,736 chigger specimens was identified from five species of small mammals (n = 217), revealing 14 chigger species, including two new records for Malaysia. The abundance and species richness of chiggers were significantly affected by habitat type (highest in forest border), state (highest in Perak), and season (highest in dry). The overall prevalence of Orientia tsutsugamushi DNA in small-mammal tissues was 11.7% and was not significantly affected by host or habitat characteristics, but in Johor, was positively associated with infestation by Leptotrombidium arenicola. These findings highlight the risk of contracting scrub typhus in oil palm plantations and associated human settlements.

Scrub typhus in urban areas of Wardha district in central India

Background & objectives

Scrub typhus caused by Orientia tsutsugamushi presents as acute undifferentiated fever and can be confused with other infectious causes of fever. We studied scrub typhus as part of a study on hospital-based surveillance of zoonotic and vector-borne zoonotic diseases at a tertiary care hospital located in the Wardha district, Maharashtra, India. We report here descriptive epidemiology and climatic factors affecting scrub typhus.

Methods

Patients of any age and sex with fever of ≥5 days were enrolled for this study. Data on sociodemographic variables were collected by personal interviews. Blood samples were tested by IgM ELISA to diagnose scrub typhus. Confirmation of scrub typhus was done by indirect immunofluorescence assay for IgM (IgM IFA). The climatic determinants were determined using time-series Poisson regression analysis.

Results

It was found that 15.9 per cent of the study participants were positive for scrub typhus by IgM ELISA and IgM IFA, both. Positivity was maximum (23.0%) in 41-60 yr of age and more females were affected than males (16.6 vs. 15.5%). Farmworkers were affected more (23.6%) than non-farm workers (12.9%). The disease positivity was found to be high in monsoon and post-monsoon seasons (22.9 and 19.4%) than in summer and winter.

Interpretation & conclusions

There were three hot spots of scrub typhus in urban areas of Wardha district. Rainfall and relative humidity in the previous month were the significant determinants of the disease.

Scrub typhus presenting as cryptogenic organizing pneumonia in a young female: A first case report

We report the case of a young female suffering from fever and generalized weakness on presentation and was diagnosed to be a case of cryptogenic organizing pneumonia (COP). She developed breathlessness on rest and required oxygen support and on further evaluation diagnosed with Scrub typhus IgM positive status. This case report highlights the importance of a rare presentation of Scrub typhus in a young female presenting with clinically silent chest changes initially and preventable worse outcomes if detected and managed for scrub typhus infection early in the course of disease.