Scrub Typhus IgM ELISA Research Articles

STUDY OF PREVALENCE OF SCRUB TYPHUS IN ACUTE FEBRILE ILLNESS IN A TERTIARY CARE HOSPITAL, VISAKHAPATNAM

Objective: Re-emergent cases of rickettsial disease, the scrub typhus is seen prevalent in cases of acute febrile illness. The objective of this study was to study the magnitude and prevalence of scrub typhus in a tertiary care hospital. Methods: This prospective study was carried on for a period of one year from February 2023 to February 2024. Inpatients between the age group of 16 to 25 y with a triad of fever for more than 5 d of onset with or without an eschar, headache, myalgia and abnormal haematological and biochemical parameters were included in the study. IgM ELISA for scrub typhus was performed. Results: Prevalence of scrub typhus in this study was 9.4% with higher male preponderance of 69.4% in 18 y age group 28.6%. Positive cases were recorded higher during post monsoon season of September 18.9%. Co-infection with dengue and malaria observed in 2 cases and ARDS was the complication in 3 cases. No mortality in this study. Conclusion: It is important to get familiar with the clinical and diagnostic laboratory findings of scrub typhus so as to differentiate it from other aetiologies of acute febrile illness.

Scrub typhus among patients with acute febrile illness in a tertiary health care centre

Scrub typhus, caused by Orientia tsutsugamushi and transmitted by bite of larval trombiculid mite of the Leptotrombidium genus and is a vector borne zoonotic disease. It has been predominantly reported from Southeast Asia, the Asian Pacific Rim, and Australia. The incidence of this disease is increased in India. These patients show an acute undifferentiated febrile illness and laboratory confirmation is essential. Delay in diagnosis may be fatal. : To assess the Scrub typhus burden among acute febrile illness patients. This Cross-sectional study, conducted in Dept. of Microbiology, Basaveshwara Medical College & Hospital, Chitradurga, Karnataka, India. Study duration was from August 2020 to January 2021. In this study, a total of 100 febrile illness patients were involved. Among them, 66 were males and 34 females. Under aseptic conditions, venous blood samples were collected from all subjects. Serum was separated by centrifugation, aliquoted, and stored at −20°C for further testing. The serum sample was tested for scrub typhus IgM ELISA using the INBIOS kit. Samples were also checked for dengue fever, typhoid fever, leptospirosis, and malaria. The serum samples that tested positive for any other infectious disease mentioned above (with or without detectable rickettsial antibodies) were excluded from the study. Data was represented in numbers and percentages. : In this study, out of 100 samples 30 were seropositive. Of the 30 seropositive scrub typhus cases, women were 11 (37%) and men were 19 (63%), suggesting that seropositivity was more in men than women. Among the seropositive cases, maximum number of the cases were in 16-30 years (33%) of age, followed by 31–45 years (23%). In this study, more number of positive cases 17 (56.6%) were found during the post-monsoon season i.e., October and November 2020. Fever, the most common symptom (100%). Headache, reported in (70 %) of cases, myalgia (40%), abdominal pain (37%), cough (23%), vomiting (20%), lymphadenopathy (17%), rashes (13%), hepato-spleenomegaly (10%), eschar (3%). The study results may conclude that Scrub typhus seropositivity rate was higher in males than females and also to be included in differential diagnosis of fever of unknown origin.

SEROPREVALENCE OF SCRUB TYPHUS AND LEPTOSPIROSIS IN PATIENTS WITH ACUTE FEBRILE ILLNESS IN A TERTIARY CARE HOSPITAL, VIJAYAWADA, A.P

Two significant causes of acute febrile illness are Scrub typhus and Leptospirosis, these zoonotic illnesses are primarily transmitted by rodents. Both illnesses present with similar and non-specific clinical symptoms, have a similar seasonal trend and can be identified by IgM ELISA. This study aims at identifying the presence of antibodies to scrub typhus and leptospirosis and their co-infection in patients of all age groups by IgM ELISA. Data was collected retrospectively over a period of four years, from January 2019 to September 2023 and analysis was done. A total number of 320 samples were received at the laboratory during the study period and IgM ELISA was performed for both scrub typhus and leptospirosis for all the samples received.Of the 320 samples tested, IgM ELISA for Scrub typhus was positive in 72(22.5%), Leptospirosis in 23(7.18%) and 6(1.87%) for both Scrub typhus and Leptospirosis were seen. Seroprevalence of Scrub typhus was more in Male population whereas Female predominance was observed in Leptospirosis. Age group in our study ranged from 0-60 years and most of the infected individuals are from Rural areas.As both leptospirosis and scrub typhus present with similar clinical features, co-infection of these two diseases may occur and require early diagnosis which helps the physician in treating the cases. IgM is a cost effective method of diagnosis of these zoonotic infections and plays a major role in early diagnosis therby reducing the morbidity and mortality in health care settings.

Molecular Diagnosis of Scrub Typhus: Sample and Timing Matter

Objective: Scrub typhus (ST) is an acute febrile illness caused by Orientia tsutsugamushi. Laboratory tests are needed to confirm the diagnosis when the characteristic eschar is absent. This study aimed to evaluate the performance of 47 kDa qPCR using clotted and EDTA-treated blood among patients with suspected ST Methods: Clotted blood samples from 284 inpatients (IPs) and EDTA-treated blood samples from 194 outpatients (OPs) with suspected scrub typhus were collected from patients who were blood culture- and malaria-negative. ST IgM ELISA and 47 kDa qPCR were performed for detection of ST infections. Results: Among the IPs (n=284) and OPs (n=194), 41% and 63% were confirmed to have ST based on the case definition, respectively; the mortality rate was 1%. The 47 kDa qPCR sensitivity of the buffy coat (65.6%) was greater compared to clotted blood (37.1%). PCR was more likely to be positive in the 1st week of the illness; IgM ELISA positivity increased after the 5th day of the illness. Conclusion: The type of sample and the time of sample collection have a role in the diagnosis of ST. These preliminary results need to be confirmed by prospective multicentric studies.

Application of Nested PCR and Loop-Mediated Isothermal Amplification (LAMP) to Target 56kDa gene in Scrub Typhus Patients and Phylogenetic Analysis to Identify Orientia tsutsugamushi Strains Circulating In and Around Puducherry

Scrub typhus (ST) is a re-emerging zoonotic disease caused by Orientia tsutsugamushi and is transmitted by chiggers. Serological tests targeting IgM and/or IgG antibodies play a major role in the detection of ST cases. Orientia 56kDa genome is common target for the molecular diagosis of ST to identify the prevalence of specific serotypes of O. tsutsugamushi in and around Puducherry by targeting 56kDa gene with the application of phylogenetic analysis. This prospective laboratory-based study was conducted in a tertiary care teaching hospital, from November 2105 to March 2018. Blood samples were collected from out-patients/in-patients, and those tested positive for ST IgM ELISA (n=140) and an equal number of negative samples were archived and anonymized. Genomic DNA was extracted and analyzed by using Nested PCR and LAMP assay. The positive products were purified and sequenced. Phylogenetic tree was constructed based on the sequences. Among 280 samples, 45 (16.1%) N-PCR and 102 LAMP (36.43%) positivity was observed for 56kDa gene. Forty-one N-PCR positive products were sequenced and accession numbers were obtained (MG601875 to MG601917) for the isolates. Phylogenetic analysis was done by Maximum Likelihood methods and this study has showed that 32.3% are similar to the Karp isolates. Molecular diagnosis of Scrub typhus has become essential in case of doubtful serology and early acute phase of illness. Gene sequencing result indicates that most of them were different from the existing ones, which may belong to the newer strains. The identification of newer strains will be helpful in future for development of scrub typhus vaccine.

A study on clinical spectrum, complications and outcome of scrub typhus infection in children admitted in pediatric department of a tertiary care hospital in West Bengal, India

Background: Scrub typhus is an important emerging etiology of febrile illnesses. Most of the studies of scrub typhus in literature have been carried out in adult population. The objective of the study is to obtain data on clinical spectrum, complications and outcome of scrub typhus infection in pediatric patients.Methods: This is a descriptive observational study, that includes 487 scrub typhus IgM ELISA positive children, conducted over a period of 36 months at Bankura Sammilani medical college & hospital, Bankura- a tertiary care government hospital in southern part of West Bengal. Data were collected in predesigned case record proforma and then analysed.Results: Highest number of cases were found among 2 to 6 years age group with male predominance, mostly from rural area & during the monsoon season. Fever, rash, headache, vomiting, cough-cold, myalgia, diarrhoea & body swelling were main presenting complaints. Hepatomegaly, lymphadenopathy, splenomegaly, eschar, pallor, edema were main examination findings. Anaemia, thrombocytopenia, leucocytosis, transaminitis were the important laboratory findings. Important complications were- hepatitis, bronchopneumonia, meningoencephalitis, pleural effusion, shock, myocarditis, acute kidney injury, respiratory failure, ARDS, MODS etc. Both azithromycin & doxycycline were effective for treatment of scrub typhus infection. Overall mortality was noted in 7.80%.Conclusions: Scrub typhus is an important re-emerging etiology of febrile illnesses in children. So, it should be kept in differentials of acute undifferentiated febrile illness in children. If diagnosed early, it is easy to treat with azithromycin and/or doxycycline and complications and mortality can be minimized significantly.

Viral Etiology in Acute Encephalitis Syndrome in North Indian Children

Background and Objective: Acute Encephalitis Syndrome (AES) leads to significant mortality and morbidity in children. This study was undertaken to identify the viral causes of AES and its correlation with clinicodemographic profile. Methods: This cross-sectional study included 100 children aged 1 to 12 years presenting with fever of <14 days duration and a change in mental status (including symptoms such as confusion, disorientation, coma, or inability to talk) and/or new onset of seizures (excluding simple febrile seizures) [1]. Cerebrospinal Fluid (CSF) was collected aseptically by lumbar puncture for biochemical and cytological analysis, and for bacteriological culture. Multiplex PCR for the viruses HSV1, HSV2, Varicella zoster virus, Enterovirus, Mumps and Parecho virus was carried out. Serology for Japanese Encephalitis (JE) was done in blood and CSF by ELISA method. Dengue NS1 antigen and IgM ELISA was carried out in both blood and CSF samples. Serum IgM antibody for scrub typhus was done by ELISA method. Results: Out of 100 children viral cause was detected in 21 patients (Japanese encephalitis -16, Dengue – 4, Varicella zoster virus, Enterovirus and Mumps virus – 1 each). Serum IgM ELISA for scrub typhus was positive in 6 patients. Multiple viral etiology was seen in 2 patients. Mortality was significantly more in females (p=0.021), GCS <8 (p <0.001). Mortality was significantly more with higher CSF neutrophils and higher proteins (p<0.05). Interpretation and Conclusion: This study concludes that viral causes specially JE contributed in AES in North India. Hence viral pathogens including JE needs to be considered as one of major causative agents while treating patients of AES and further emphasis has to be given for JE vaccination in this region.

ACUTE DISSEMINATED ENCEPHALOMYELITIS AS A COMPLICATION OF SCRUB TYPHUS

Scrub typhus is an acute febrile illness usually characterized by eschar, lymphadenopathy, multisystem involvement caused by Orientia tsutsugamushi. Scrub typhus as a cause of acute disseminated encephalomyelitis (ADEM) is extremely rare. This is a case report of a 40 years old female presenting with sudden onset altered sensorium, bilateral lower limb weakness with difculty in walking, irrelevant speech, urinary and bowel retention since two days, high grade intermittent fever associated with headache and multiple episodes of vomiting for past one week. Cerebro spinal uid study showed lymphocytic pleocytosis with mildly increased protein. MRI brain showed multifocal encephalitis & MRI spine revealed demyelination at spinal cord suggestive of ADEM. Paired CSF & serum scrub typhus IgM ELISA was found to be positive. She was ultimately diagnosed as a case of scrub typhus complicated with ADEM. After treatment with doxycycline and methylprednisolone patient improved dramatically without any residual neurological decit during discharge. This case report highlights that scrub typhus should be included in the differentials in patients presenting withADEM for early diagnosis and treatment in order to reduce mortality and morbidity.

Serological Evidence of Scrub Typhus in Mizoram, North Eastern Region of India.

Differentiating scrub typhus from other acute febrile illnesses is difficult due to non-specificity of clinical symptoms and relative absence of eschar in Indian population. Antibody based serological tests are mainstay of scrub typhus diagnosis. To order to determine the performance of immunochromatography and IgM ELISA, immunochromatography and scrub typhus IgM ELISA were performed to detect the presence of antibodies against Orientia tsutsugamushi in acute serum of patients with acute febrile illness. A cross-sectional study was carried out in the Department of Microbiology, Civil Hospital Aizawl and Department of Microbiology, Civil Hospital Lunglei, Mizoram over a period of one year from October 1, 2018 to September 31, 2019. Serum samples from patients with acute febrile illness were processed for the detection of scrub typhus. A total of 253 samples were subjected to immunochromatography and IgM ELISA. Using scrub typhus IgM ELISA as gold standard, the sensitivity, specificity and negative predictive value were calculated. Of the 253 serum samples tested, 36 were positive by both scrub typhus rapid test and IgM ELISA. 27 samples which were negative by scrub typhus rapid test reacted positive by IgM ELISA. 66 samples which were positive by scrub typhus rapid test were negative by IgM ELISA. Owing to the limitations of scrub typhus rapid test and immunfluorescence assay (IFA), commercially available recombinant IgM ELISA which has a good sensitivity and specificity may be an alternative in laboratories with moderate set up.

A study on serodiagnosis of scrub typhus in a Teaching Hospital of South India

Background: crub typhus is caused by Orientia tsutsugamushi (rickettsial disease) commonly transmitted by the bite of larval chiggers of trombiculid mites. It has been one of the important causes of febrile illness, especially in south India. The clinical diagnosis is difficult owing to the non-specific presentation. We in the current study tried to evaluate the serodiagnosis of scrub typhus with the Weil Felix test and IgM ELISA. Methods: This study was conducted in the Department of Microbiology, Prathima Institute of Medical Sciences, Naganoor, Karimnagar. All the sera samples were subjected to the Weil Felix test using Proteus OX2, OX19, OX-K strain agglutination test, and subsequently, Scrub typhus IgM ELISA test. Results: All the samples were subjected to the Weil Felix test n=4(6.06%) were positive for scrub typhus (OXK antigen) n=11(16.67%) were positive for the spotted group of fever (OX2 antigen) and n=10 (15.15%) were positive of typhus group (OX19 antigen). N=5 sera samples were positive for more than one type of antigens. All the n=66 serum samples were subjected to IgM ELISA for scrub typhus. Out of n=66, only two serum samples (3.03%) were positive by IgM ELISA. Conclusion: Scrub typhus is emerging as an important public health issue. It is one of the important causes of acute febrile illness. Although it is difficult to distinguish scrub typhus based on the clinical symptoms alone a simple test such as Weil Felix was found to be promising in the diagnosis of scrub typhus. ELISA IgM test may be performed additionally in laboratories with adequate facilities. Hence for clinicians, any case with a fever of unknown origin should arouse suspicion of scrub typhus

Spectrum of Multiorgan Dysfunction in Scrub Typhus Infection.

We planned this study to determine the clinical spectrum and compare incidence of multiorgan dysfunction in children hospitalized with scrub typhus with other etiologies of tropical fever. Prospective cohort study. Pediatric emergency and PICU services of a university teaching hospital situated in the sub-Himalayan region. Children aged 2 months to 14 years with acute undifferentiated fever of more than 5 days. Detailed fever workup was performed in all children. We compared scrub typhus IgM positive children (cases) with remaining febrile children who were negative for scrub IgM assay (controls) for mortality and morbidity. We enrolled 224 febrile children; 76 children (34%) were positive for scrub typhus IgM ELISA. Scrub typhus group had a significantly higher incidence of multiorgan dysfunction [OR 3.5 (95% CI 2.0-6.3); p < 0.001] as compared to non-scrub typhus group requiring supportive care. The incidence of altered sensorium [OR 8.8 (95% CI 3.1-24.9)], seizures [OR 3.0 (95% CI 1.1-8.3)], acute respiratory distress syndrome [OR 17.1 (95% CI 2.1-140.1)], acute renal failure (5% vs. 0%), meningitis [OR 6.2 (95% CI 1.2-31.6)], thrombocytopenia [OR 2.8 (95% CI 1.5-5.1)], transaminitis [OR 2.7 (95% CI 1.6-4.8)], requirement of oxygen [OR 17.8 (95% CI 4.0-80.3)], positive pressure support [OR 3.7 (95% CI 1.2-10.5)] and shock requiring inotropes [OR 3.0 (95% CI 1.3-6.7)] was significantly higher in scrub typhus group as compared to the non-scrub typhus group (Table 1). Pediatric scrub typhus who were hospitalized had severe systemic manifestations when compared to other causes of fever.

Serological Detection and Epidemiological Factors Associated with Scrub Typhus among Undifferentiated Febrile Illness Patients in a Tertiary Care Hospital

Scrub typhus is an arthropod-borne zoonotic bacterial infection caused by Orientia tsutsugamushi. It presents clinically as a non-specific febrile illness that needs a high index of clinical suspicion for diagnosis. The mortality rate can be as high as 30% if not treated appropriately. Laboratory diagnosis is therefore important for confirming the cause of illness prior to initiating appropriate therapy. Hence we aimed to detect scrub typhus in serum samples of undifferentiated febrile illness patients and to correlate with the socioeconomic status of these individuals. We also aimed to study the seasonal variation associated with the disease. Serum samples from 143 febrile patients who were negative for other febrile illnesses were subjected to scrub typhus IgM ELISA. Scrub typhus IgM antibodies were found in 14 (9.8%) individuals of which 41-60 years being the most affected age group. Scrub typhus positivity was high during the months of October to December (P value 0.0056) with the individuals from the rural areas being the most affected (P value 0.027). To conclude, this study emphasises the importance of serological tests to detect scrub typhus and to include it as a differential diagnosis among undifferentiated febrile illnesses.

Clinico-pathological profile of scrub typhus in children: a cross sectional study from Eastern India

Background: Scrub typhus is a vector-borne zoonosis, endemic in Asia and it may present as an undifferentiated fever or with multisystem involvement. This study was carried out to understand the varied presentation of scrub typhus in children and the response to treatment in a tertiary care hospital in Eastern India.Methods: All children between 1 month and 12 year of age admitted with fever for more than 5 days and positive IgM ELISA for scrub typhus were included in the study and their course in hospital was documented. They were randomly divided into 2 groups of 41 patients each, into doxycycline and azithromycin group and were then evaluated for therapeutic response.Results: In this study, pallor (89%) was the commonest finding followed by hepato-splenomegaly (73.2%), pneumonia (65.9%) and rash was found in 43.9%. Eschar was found in 32.9% whereas serious complications like shock and meningoencephalitis was found in 9.8%. Pericardial effusion was detected in 23.2% cases, coronary artery dilatation in 11% cases and both effusion as well as coronary artery dilation was found in 2.4%. In azithromycin group, 73.2% patients had drug response whereas in doxycycline group, 92.7% patients had drug response and this association was statistically significant (p=0.0188). Two patients who presented late with shock expired but all others responded to treatment and were doing well on follow up.Conclusions: Scrub typhus may present with multisystem involvement including cardiac manifestation which needs to be identified early by echocardiography. Doxyclycine is still the best modality of treatment and if used early, outcome is favourable.

Etiological Trends and Epidemiological Profile of Tropical Fever in Children Presenting with Acute Undifferentiated Fever at a Tertiary Care Centre in North India

&#x0D; &#x0D; &#x0D; &#x0D; Introduction: The objective of this study was to determine the etiology of acute undifferentiated fevers (AUF) in hospitalised children with in a tertiary care centre in North India. The various causes of acute undifferentiated fevers included dengue, malaria, scrub typhus, enteric fever, leptospirosis and Chikungunya. The clinical spectrum and therapeutic outcome of these cases was also studied.&#x0D; Methods: This retrospective study was conducted over a period of 6 months from June 2019 to December 2019. The clinical information of 126 children who tested positive for any of the causes of AUF namely dengue, malaria, scrub typhus, enteric fever, chikungunya and leptospirosis was obtained from the Paediatrics Department. The information was recorded in a predesigned proforma. Various tests performed for the diagnosis of these illnesses were noted. They included dengue NS1 antigen ELISA and IgM ELISA, peripheral blood smear (PBS) for malarial parasite and rapid malarial antigen detection test (RMAT), scrub typhus IgM ELISA, leptospira IgM ELISA, and Chikungunya IgM ELISA.&#x0D; Results: The diagnosis of AUF were dengue (55.5%; 70/126), malaria (19%; 24/126) and scrub typhus (19%; 24/126), enteric fever (4.7%;6/126) and Chikungunya (1.5%; 2/126). The most common presenting symptom was fever or pyrexia followed by myalgia, generalised aches and pains in the body and vomiting. Commonly observed complications included thrombocytopenia, hepatitis and shock.&#x0D; Conclusions: Dengue, malaria and scrub typhus are the major causes of AUF in the hospitalised children with dengue being the most prevalent infection. The study further emphasises the need to develop a systematic approach to the diagnosis of AUFs. This should be using a combination of clinical, epidemiological and laboratory parameters, which will be very useful for developing a relevant action plan for treatment and prevention of such fevers in any hospital setup.&#x0D; &#x0D; &#x0D; &#x0D;

Eschar and IgM ELISA in the Diagnosis of Scrub Typhus

AbstractScrub typhus is one of the leading causes of acute febrile illness in India. This study aimed to determine the best diagnostic tool for the identification of scrub typhus and study the possible association between diagnostics and clinical characteristics. Patients with fever of ≤15 days admitted to the hospital satisfying the case definition of 47 kDa quantitative polymerase chain reaction (qPCR) positivity OR scrub typhus IgM ELISA positivity along with the presence of eschar OR Scrub typhus IgM ELISA positivity along with defervescence of fever within 72 h of initiation of specific therapy were recruited. Of the 116 patients satisfying the case definition, 47 kDa qPCR was positive in 43 (37%) patients, whereas IgM ELISA was positive in 104 (90%) patients and eschar was seen in 59 (51%) patients. The median duration of fever was 7.5 days (interquartile range 6–10 days). Multiorgan dysfunction syndrome (MODS) was described in 44 (37.9%) patients. Two patients (1.8%) succumbed to the illness. Presence of eschar and IgM ELISA positivity were detected in 106 (91%) cases. Scrub typhus, even with MODS, has low mortality because of immediate institution of specific therapy due to physician awareness. The presence of eschar and IgM ELISA positivity can be used to detect a majority of cases of scrub typhus.

Analysis of 262 Children with Scrub Typhus Infection: A Single-Center Experience.

Scrub typhus, a vector-borne rickettsiosis, is the leading treatable cause of non-malarial febrile illness in Asia. The myriad of typical and atypical features poses a clinical conundrum. We aimed to study the clinical and laboratory profile of children with scrub typhus infection diagnosed by IgM ELISA. Data of children < 12 years presenting with undifferentiated fever to the pediatric services of a tertiary teaching institute between January 2012 and December 2018 were retrieved. Children with seropositive IgM ELISA (InBios International Kit, Seattle, WA) for scrub typhus were enrolled in the study. Clinical features, laboratory investigations, treatment received, and the outcome recorded were obtained. Objective evidence of organ dysfunction was taken as severe scrub typhus. In total, 262 children were diagnosed with scrub typhus. The mean age was 5 years, with male preponderance (65%). And, 13 children presented during infancy. Fever was universal, and generalized lymphadenopathy (93.5%) and hepatomegaly (70%) were the common clinical signs. Eschar was identified in 31%, with greater predilection for groin and axilla. Thrombocytopenia was striking in one-third of children. Also, 25 children (9.5%) had severe scrub typhus and 18 required intensive care stay. Elevated aspartate aminotransferase enzyme levels was a predictor of severity ([OR 3.9], P value 0.005) by multivariate analysis. Lymphadenopathy was found significantly associated with eschar (P < 0.005). No mortality was recorded. This 6-year study underscores the varied spectrum of pediatric scrub typhus infection. Zero mortality in our cohort signifies the excellent outcome with judicious first-line antibiotics.

Clinical Characteristics and Predictors of Severity of Pediatric Scrub Typhus in a Tertiary Level Hospital in South India

BackgroundScrub typhus, a zoonosis caused by bacteria Orientia tsutsugamushi is associated with varying clinical features and significant mortality due to complication in view of ineffective treatment.ObjectivesThis study was undertaken to identify the factors for predicting severity in scrub typhus.MethodsThis retrospective study was conducted at a tertiary care teaching hospital between January 2015 to October 2016. All children younger than 18 years of age admitted with a history of fever for more than seven days and positive IgM ELISA for scrub typhus were included in the study. Cases of “severe scrub typhus” were identified based on criteria from published pediatric studies. A total of 235 patients tested positive for scrub typhus, out of which 39 patients were in the severe scrub group and 196 in the non-severe group. Reports were analyzed for the predictors of severity of scrub typhus in both groups.ResultsUsing multivariate analysis, the factors for predicting severity in scrub typhus were hemoglobin 5 fold rise (OR = 49.7, CI = 13.49 to 183.17), prolongation of PT (P value = 0.03), and altered sensorium (P value = 0.016) were correlated with severe disease.ConclusionsWe conclude that altered sensorium, anemia, thrombocytopenia, elevated transaminases, hypoalbuminemia, and prolongation of prothrombin time to be predictors of severity of illness in scrub typhus.

A single-centre experience of scrub typhus in a tertiary care centre - a re-emerging infection

Background: Scrub typhus is a documented disease in Himachal Pradesh, but there have been few clinico-epidemiological studies in this area. The present study is done with IgM ELISA as a diagnostic test which has higher sensitivity and specificity as most of the previous studies had used Weil Felix test as a diagnostic test. Methodology: This was a prospective observational study. All the patients more than 18 years of age with positive IgM ELISA for scrub typhus with/without eschar were included. The clinical profile was observed. IgM scrub typhus was done by ELISA. Results: Total of 39 patients were observed between July 2016 to Dec 2016. Maximum patients were observed in August, September, and October. Fever with Headache was the most common presenting complaint. Eschar was present in 10 % patients. Complications were seen in 76.92 %. The mortality rate was 0 %. Conclusion: The varied presentations and high rate of complications require a high index of suspicion for Scrub Typhus. The general physicians should be sensitized for the early diagnosis and treatment to reduce morbidity and mortality.

Assessment of Two Immunoassays for Detection of IgM Antibodies to Scrub Typhus Using a Serum Panel

AbstractLaboratory tests are necessary for diagnosis of scrub typhus (ST) especially in the absence of the distinctive eschar. Performance of an ELISA and ICT (immunochromatography) to detect IgM antibodies to scrub typhus was assessed using a panel of 346 sera chosen from healthy individuals, those with scrub typhus and scrub-typhus like illness. A sensitivity of 98.7% for ST IgM ICT and 97.4% for ST IgM ELISA was observed while specificity was 96.3% for ICT and 95.9% for ELISA. As excellent concordance (98.8%) was noted between the two assays, IgM ICT can be used for rapid diagnosis of scrub typhus.

Determination of Optimal Diagnostic Cut-Offs for the Naval Medical Research Center Scrub Typhus IgM ELISA in Chiang Rai, Thailand.

.In this diagnostic accuracy study, we evaluated data from 135 febrile patients from Chiang Rai, to determine the optimal optical density (OD) cutoffs for an in-house scrub typhus IgM ELISA. Receiver operating characteristic curves were generated using a panel of reference assays, including an IgM immunofluorescence assay (IFA), PCR, in vitro isolation, presence of an eschar, or a combination of these. Altogether, 33 patients (24.4%) were diagnosed as having scrub typhus. Correlation between positivity by IFA and increasing OD values peaked at a cutoff of 2.0, whereas there was little association between positivity by culture or eschar with increasing ELISA cutoffs—cutoffs of 3.0 and 4.0 were demonstrated to be optimal for the total absorbance of the OD at dilutions 1:100, 1:400, 1:1,600, and 1:6,400, for admission and convalescent samples, respectively. The optimal cutoff at a 1:100 dilution was found to be between 1.85 and 2.22 for admission samples and convalescent-phase samples, respectively. Sensitivities for the cutoffs varied from 57.1% to 90.0% depending on the reference test and sample timing, whereas specificities ranged from 85.2% to 99.0%. We therefore recommend a cutoff of around 2.0, depending on the sensitivity and specificity desired in clinical or epidemiological settings. The results demonstrate the ELISA to be a valuable diagnostic tool, suitable for use in resource-limited endemic regions, especially when used in combination with other diagnostic modalities such as the presence of an eschar.