Scrub typhus in Southern India: are we doing enough?

Scrub Typhus in Paediatric Age Group at a Tertiary Care Centre of Eastern India: Clinical, Biochemical Profile and Complications

Background

Scrub typhus is a reemerging zoonosis, which presents as acute febrile illness. Very few paediatric prospective studies on this disease are reported from Eastern India. This prospective observational study was carried out to study the clinical presentation, diagnosis, complications and immediate outcome of Scrub typhus in paediatric population in a tertiary care hospital from Eastern India.

Material and Methods

Totally 209 cases between 1 month and 18 years of age were included. Clinical manifestations, laboratory parameters and immediate outcome of all patients were recorded. All the data were collected and plotted in Microsoft Excel master chart. Continuous data were presented as mean ± standard deviation (SD) and categorical data as frequency and percentage. All the data analysis was performed using statistical software IBM Statistical Package for the Social Sciences (SPSS) version 20.0.

Results

Highest number of cases (41.1%) were found between 1 year and 5 years age group. Fever was the presenting complaint in all cases. Other common symptoms were cough (34%), pain abdomen (23.4%), vomiting (23%), seizure (11.5%) and altered sensorium (9.6%). Hepatomegaly was found in 56.5% and splenomegaly in 39.7% cases. Eschar was found in 27.3% cases. C-reactive protein was elevated (>10 mg/L) in 93.3% children. Other complications were pneumonitis (20.6%), meningoencephalitis (12.4%), septic shock (8.6%), acute respiratory distress syndrome (5.7%), myocarditis (4.8%) and acute kidney injury (4.3%). Mortality was low (1%).

Conclusion

Scrub typhus is not uncommon in paediatric population and it must be considered as a close differential diagnosis of any acute febrile illness even when classical clinical presentations are not found. Early treatment results in favourable outcome.

Predictors of Severity of Scrub Typhus in Children Requiring Pediatric Intensive Care Admission

Objective of our study was to determine the clinical characteristics and laboratory profile of scrub typhus patients requiring pediatric intensive care admission and to find out risk factors for the severity of illness. This was a cross-sectional observational study conducted on 1-month to 12-year-old children admitted with scrub typhus in a tertiary care pediatric intensive care unit (PICU). Relevant demographic, clinical, laboratory, treatment, and outcome-related data were documented. The severity of the disease was measured in the form of multiple organ dysfunction syndrome (MODS). With further correlation, and univariate and multivariate analyses, factors associated with severe disease were identified. During the study period, out of 586 PICU admission, 62 patients (10.6%) were diagnosed with scrub typhus. The mean age was 63.85 ± 52.78 months, where infants constituted 32.3% of the total population. Fever was present in 100% of the cases. Common indications of PICU admission were: respiratory distress 42 (67.7%), altered sensorium 41 (66.1%), convulsion 37 (59.7%), and shock 31 (50%). Total number of patients with MODS was 40 (64.5%). The case fatality rate was 8%. On multivariate analysis, infant age group (p = 0.02), altered sensorium (p = 0.001), reduced urine output (p = 0.02), thrombocytopenia (p = 0.001), raised C-reactive protein (p = 0.004), hyponatremia (p = 0.005), hypoalbuminemia (p = 0.01), deranged international normalized ratio (p = 0.02), and hyperferritinemia (p = 0.02) came out to be independent factors in predictability for development of MODS. Multiorgan dysfunction is a life-threatening manifestation of scrub typus in children, which necessitates PICU admission. Infant age group, presence of altered sensorium, reduced urine output, thrombocytopenia, elevated inflammatory markers, coagulopathy, hypoalbuminemia, and hyponatremia predict risk for MODS.

Non-linear effect of different humidity types on scrub typhus occurrence in endemic provinces, Thailand

Background

Reported monthly scrub typhus (ST) cases in Thailand has an increase in the number of cases during 2009–2014. Humidity is a crucial climatic factor for the survival of chiggers, which is the disease vectors. The present study was to determine the role of humidity in ST occurrence in Thailand and its delayed effect.

Methods

We obtained the climate data from the Department of Meteorology, the disease data from Ministry of Public Health. Negative binomial regression combined with a distributed lag non-linear model (NB-DLNM) was employed to determine the non-linear effects of different types of humidity on the disease. This model controlled overdispersion and confounder, including seasonality, minimum temperature, and cumulative total rainwater.

Results

The occurrence of the disease in the 6-year period showed the number of cases gradually increased summer season (Mid-February – Mid-May) and then reached a plateau during the rainy season (Mid-May – Mid-October) and then steep fall after the cold season (Mid-October – Mid-February). The high level (at 70%) of minimum relative humidity (RHmin) was associated with a 33% (RR 1.33, 95% CI 1.13–1.57) significant increase in the number of the disease; a high level (at 14 g/m³) of minimum absolute humidity (AHmin) was associated with a 30% (RR 1.30, 95% CI 1.14–1.48); a high level (at 1.4 g/kg) of minimum specific humidity (SHmin) was associated with a 28% (RR 1.28, 95% CI 1.04–1.57). The significant effects of these types of humidity occurred within the past month.

Conclusion

Humidity played a significant role in enhancing ST cases in Thailand, particularly at a high level and usually occurred within the past month. NB-DLNM had good controlled for the overdispersion and provided the precise estimated relative risk of non-linear associations. Results from this study contributed the evidence to support the Ministry of Public Health on warning system which might be useful for public health intervention and preparation in Thailand.

Diagnostic tools used in the evaluation of acute febrile illness in South India: a scoping review

BACKGROUND

Acute febrile illness (AFI) is characterized by malaise, myalgia and a raised temperature that is a nonspecific manifestation of infectious diseases in the tropics. The lack of appropriate diagnostics for the evaluation of AFI leads to increased morbidity and mortality in resource-limited settings, specifically low-income countries like India. The review aimed to identify the number, type and quality of diagnostics used for AFI evaluation during passive case detection at health care centres in South India.

METHODS

A scoping review of peer-reviewed English language original research articles published between 1946-July 2018 from four databases was undertaken to assess the type and number of diagnostics used in AFI evaluation in South India. Results were stratified according to types of pathogen-specific tests used in AFI management.

RESULTS

The review included a total of 40 studies, all conducted in tertiary care centres (80% in private settings). The studies demonstrated the use of 5-22 tests per patient for the evaluation of AFI. Among 25 studies evaluating possible causes of AFI, 96% tested for malaria followed by 80% for dengue, 72% for scrub typhus, 68% for typhoid and 60% for leptospirosis identifying these as commonly suspected causes of AFI. 54% studies diagnosed malaria with smear microscopy while others diagnosed dengue, scrub typhus, typhoid and leptospirosis using antibody or antigen detection assays. 39% studies used the Weil-Felix test (WFT) for scrub typhus diagnosis and 82% studies used the Widal test for diagnosing typhoid.

CONCLUSIONS

The review demonstrated the use of five or more pathogen-specific tests in evaluating AFI as well as described the widespread use of suboptimal tests like the WFT and Widal in fever evaluation. It identified the need for the development of better-quality tests for aetiological diagnosis and improved standardised testing guidelines for AFI.

Under-diagnosis of rickettsial disease in clinical practice: A systematic review

BACKGROUND

Rickettsial diseases present as acute febrile illnesses, sometimes with inoculation eschars.

METHODS

We performed a systematic review of studies published between 1997 and 2017 to assess the underestimation of non-eschar rickettsial disease (NERD) relative to eschar rickettsial disease (ERD), as a cause of acute fever in patients with rickettsial diseases that commonly present with eschar(s): scrub typhus (ST), Mediterranean spotted fever (MSF), and African tick-bite fever. We compared ERD/NERD ratios according to study design: 'complete approach' studies, with testing performed in all patients with 'unspecified febrile illness'; versus 'clinical judgement' studies, with testing performed if patients presented with specific symptoms.

RESULTS

In 'complete approach' studies, ERD/NERD ratios were significantly lower, suggesting a considerable under-diagnosis of NERD in 'clinical judgement' studies. Based on these results, we estimate that the diagnosis of rickettsial disease was missed in 66.5% of patients with ST, and in 57.9% of patients with MSF.

CONCLUSIONS

Study design influences the reported eschar rates in ST and MSF significantly. NERD is likely to be a vastly underdiagnosed entity, and clinicians should consider and test for the disease more often.

PROSPERO REGISTRATION NUMBER

CRD 42016053348.

Clinico - Laboratory Profile of Scrub Typhus - An Emerging Rickettsiosis in India

OBJECTIVE

To study the clinical and laboratory profile of pediatric scrub typhus in rural south India.

METHODS

This is a descriptive study of the clinical and laboratory features of 117 children with IgM ELISA proven scrub typhus out of 448 children, who were admitted in the Pediatric ward of a tertiary care hospital, during the study period of November 2014 through March 2015.

RESULTS

Fever was present in all 117 children, with mean duration of fever at admission as 9 d. Gastrointestinal tract was the most commonly affected system, seen in 51 % of children. Cough (82 %), myalgia (70 %), vomiting (68 %), headache (45 %) and pain abdomen (42 %) were the most common symptoms of scrub typhus. Hepatomegaly (70), splenomegaly (53 %), pallor (50 %) and eschar (41 %) were the common clinical findings in children with scrub typhus. Out of 49 children with eschar, 32 were associated with regional lymphadenopathy, which was commonly seen in axillary, neck and groin regions. Leucocytosis (50 %), anemia (56 %), increased SGOT / SGPT (47 %), thrombocytopenia (41 %), hypoalbuminemia (40 %) and hyponatremia (40 %) were the common lab features. Shock (46 %), myocarditis (24 %) and pneumonia (16 %) were the common complications seen in these children. This study showed that early treatment for scrub typhus results in a good outcome in terms of early recovery and nil mortality.

CONCLUSIONS

Regional lymphadenopathy is a marker of hidden or developing eschar. Total count and differential count should be interpreted on the background of the duration of fever. Since IgM ELISA, which is diagnostic of scrub typhus may not be widely available, any febrile child coming from rural area with hepatosplenomegaly, pallor, eschar, generalised / regional lymphadenopathy, anemia, leucocytosis, thrombocytopenia and increased Aspartate transaminase (AST) /Alanine aminotransferase (ALT) should be started on empirical Doxycycline or Azithromycin in order to prevent life threatening complications secondary to delay in therapy.

Scrub Typhus: A Clinico-Laboratory Differentiation of Children with and without Meningitis

Neurological involvement in the form of meningitis or meningoencephalitis, although well documented in scrub typhus, has not been extensively studied in the pediatric population. We report the clinical and laboratory profile of 96 children with scrub typhus and compared those with and without meningitis. Twenty seven (28%) children had clinical and laboratory evidence of meningitis. The most frequent presenting features were fever (100%), meningeal signs (66.6%), nausea and vomiting (56.3%), seizures (55.5%) and altered sensorium (51.8%). The children with meningitis presented early and had significantly lower respiratory and renal impairments when compared with the non-meningitis group. Cerebrospinal fluid (CSF) analysis revealed elevated total leukocyte count (86.73 ± 94.50 cells/mm(3)), mononuclear pleocytosis (lymphocyte percentage of 76.85 ± 15.86), elevated proteins (108.33 ± 52.63 mg%) and normal CSF glucose (64.18 ± 15.92 mg%). We conclude that meningitis is a common and early complication of childhood scrub typhus. The CSF reveals a lymphocytic pleocytosis, raised proteins and a normal glucose level. These children respond promptly to appropriate antibiotics as do children without meningitis.

Burden of disease measured by disability-adjusted life years and a disease forecasting time series model of scrub typhus in Laiwu, China

Background

Laiwu District is recognized as a hyper-endemic region for scrub typhus in Shandong Province, but the seriousness of this problem has been neglected in public health circles.

Methodology/Principal Findings

A disability-adjusted life years (DALYs) approach was adopted to measure the burden of scrub typhus in Laiwu, China during the period 2006 to 2012. A multiple seasonal autoregressive integrated moving average model (SARIMA) was used to identify the most suitable forecasting model for scrub typhus in Laiwu. Results showed that the disease burden of scrub typhus is increasing yearly in Laiwu, and which is higher in females than males. For both females and males, DALY rates were highest for the 60–69 age group. Of all the SARIMA models tested, the SARIMA(2,1,0)(0,1,0)₁₂ model was the best fit for scrub typhus cases in Laiwu. Human infections occurred mainly in autumn with peaks in October.

Conclusions/Significance

Females, especially those of 60 to 69 years of age, were at highest risk of developing scrub typhus in Laiwu, China. The SARIMA (2,1,0)(0,1,0)₁₂ model was the best fit forecasting model for scrub typhus in Laiwu, China. These data are useful for developing public health education and intervention programs to reduce disease.

Scrub typhus, also known as tsutsugamushi disease, is a zoonosis transmitted by chigger bites (larval trombiculid mites) and the pathogen Orientia tsutsugamushi (O. tsutsugamushi), a Gram-negative obligate intracellular bacterium. It is distributed widely in the Pacific regions of Asia, and the islands of the western Pacific and Indian Oceans. People with outdoor activities that involve contact with grasses or shrubs are at highest risk. Scrub typhus has existed in Southern China for thousands of years, but it has been noted to spread from the South to the North of China in recent decades. Though this research we studied the disease burden of scrub typhus with disability-adjusted life years (DALYs), and developed a forecasting time series model for human clinical disease in Laiwu, China. Results demonstrated that the disease burden of scrub typhus was increasing year by year in Laiwu, and it was higher in females than males. Moreover, DALY rates in females and males were highest for persons in the 60–69 years age group. Of all the seasonal autoregressive integrated moving average (SARIMA) models tested, the SARIMA(2,1,0)(0,1,0)₁₂ model was the best fit for scrub typhus cases in Laiwu. The disease occurred mainly in autumn, with a peak in October.

A prospective study on distribution of eschar in patients suspected of scrub typhus

Scrub typhus is an acute febrile illness caused by a tick bite infected with the bacteria Orientia tsutsugamushi. The clinical diagnosis is difficult as the symptoms are similar to other febrile illnesses such as dengue, typhoid, leptospirosis and so on. An eschar, if present, will narrow down the provisional diagnosis towards scrub typhus. There are no data on the preferential sites of tick bites in an Indian population. We present here the preferential sites of tick bites in a South Indian population of 123 cases positive for eschar. Geographically, clothing styles vary leading to the differences in the areas of skin exposed to the bite and thus the formation of eschars. Scrub typhus, if not treated, may lead to fatal complications. As scrub typhus is one of the most under-reported illnesses in the world, clinicians should look for the presence of an eschar in the preferential sites at least to narrow down the diagnosis and treatment.

Effects of meteorological factors on scrub typhus in a temperate region of China

Scrub typhus is emerging and re-emerging in many areas: climate change may affect its spread. To explore the effects of meteorological factors on scrub typhus, monthly cases of scrub typhus from January 2006 to December 2012 in the Laiwu district of temperate northern China were analysed. We examined the correlations between scrub typhus and meteorological factors (and their delayed effects). We built a time-series adjusted negative binomial model to reflect the relationships between climate variables and scrub typhus cases. The key determinants of scrub typhus transmission were temperature, relative humidity and precipitation. Each 1°C increase in monthly average temperature in the previous 3 months, each 1% increase in monthly relative humidity in the previous 2 months and each 1 mm increase in monthly precipitation in the previous 3 months induced 15·4%, 12·6% and 0·7% increases in the monthly number of cases, respectively. In conclusion, scrub typhus is affected by climate change in temperate regions.

Pure cerebellitis due to scrub typhus: a unique case report

We report the case of a 24-year old Indian man who presented with: high fever; drowsiness; an eschar and gross cerebellar dysfunction with horizontal gaze nystagmus; ataxic speech; and truncal ataxia. Scrub typhus was diagnosed by serological tests. This is the first case of a pure cerebellar involvement as the only manifestation of scrub typhus in the published literature.

Scrub typhus associated acute kidney injury--a study from a tertiary care hospital from western Himalayan State of India

OBJECTIVE

To report the clinical profile of acute kidney injury (AKI) associated with scrub typhus.

METHODS

Retrospective study of hospitalized patients of acute febrile illness who were diagnosed scrub typhus and had AKI.

RESULTS

174 (35%) patients (75.9% female), mean age (41.4 ± 15.9 years) were studied. The laboratory abnormalities were: anemia (63.2%), leukocytosis (44.3%), thrombocytopenia (61.5%), hyponatremia (35.6%), hypernatremia (2.9%), and hypokalemia (12.1%), hyperkalemia (11.5%), hypoalbuminemia (56.9%), hepatic dysfunction (70%) and metabolic acidosis (28.7%). The complications of hypotension (5.7%), septic shock (3.4%), pneumonia (10.9%), acute respiratory distress syndrome (ARDS) (11.5%), meningoencephalitis (6.9%), encephalopathy (5.2%), gastrointestinal bleed (1.3%), myocarditis (3.4%), disseminated intravascular coagulation (2.9%) and multi organ failure (MOF) (10.3%) developed during course of hospitalization in these patients. Twenty-five (14.4%) patients required intensive care support (ICU) support and seven (4%) patients were dialyzed. 146 (83.9%) patients survived. Twenty-eight (16.1%) patients died. There was a significant difference in the age, various hematological & biochemical abnormalities, complications and need for ICU support in the non-survival group as compared the survival group.

CONCLUSION

This study shows that AKI in scrub typhus is common and a severe disease. Age, a shorter hospital stay, severities of leukocytosis, thrombocytopenia, azotemia, hypoalbuminemia, hepatic dysfunction and the complications of ARDS, encephalopathy, MOF and need for ICU support are the factors associated with mortality.

First case of scrub typhus with meningoencephalitis from Kerala: An emerging infectious threat

Scrub typhus is a rickettsial disease caused by Orientia tsutsugamushi, one of the most common infectious diseases in the Asia-Pacific region. It has been reported from northern, eastern, and southern India, and its presence has been documented in at least 11 Indian states. However, scrub typhus meningoencephalitis has not been well documented in Kerala. We report two cases of scrub typhus meningoencephalitis from northern Kerala. The diagnosis was made based on the clinical pictures, presence of eschar, and a positive Weil–Felix test with a titer of > 1:320. The first patient succumbed to illness due to respiratory failure and the second patient improved well.

Imported scrub typhus in The Netherlands

Two cases of travel-acquired scrub typhus imported in the Netherlands are described. The characteristic eschar was absent in both cases. One case acquired scrub typhus in non-rural surroundings in India, highlighting that scrub typhus must also be considered a (sub) urban zoonosis.

Meta-analysis of drug treatment for scrub typhus in Asia

OBJECTIVE

Scrub typhus is an important febrile disease in Asia, and antibiotics have been used to treat this disease. The purpose of this study was to generate large-scale evidence of the efficacy of different antibiotic regimens for treating scrub typhus using a meta-analysis.

METHODS

PubMed, Elsevier ScienceDirect, Chinese Biomedical Literature Database (CBM), China National Knowledge Infrastructure (CNKI), and Wanfang (Chinese) were searched to identify relevant articles. The data from eligible citations were extracted by two reviewers. All analyses were performed using the Cochrane Collaboration Review Manager 4.2 and Stata 10.0 software programs.

RESULTS

We conducted a meta-analysis of 17 separate studies that evaluated the efficacy of treatment with the different antibiotic regimens for scrub typhus. The median time (h) to clearance of fever in the azithromycin-treated group was longer than that in the chloramphenicol-treated group (weighted mean difference [WMD] = 12.66, 95% confidence interval [CI]: 2.26,23.06). Adverse events were 2.95 (95%CI: 1.32, 6.61) times more likely to occur in the azithromycin-treated group than in the chloramphenicol-treated group. The clearance time (days) for the main symptoms (including fever, headache, rash and lymphadenectasis) in the doxycycline-treated group was shorter than that in the chloramphenicol-treated group (WMD = -0.4, 95%CI: -0.53, -0.26) in five trials. Adverse drug events occurred significantly less frequently in the azithromycin-treated group than in the doxycycline-treated group (relative risk [RR] = 0.47, 95%CI: 0.31,0.71).

CONCLUSION

Doxycycline was found to act more quickly, but more adverse drug events occur when using this regimen compared to azithromycin and chloramphenicol.