JCDR - Register at Journal of Clinical and Diagnostic Research
Journal of Clinical and Diagnostic Research, ISSN - 0973 - 709X
Internal Medicine Section DOI : 10.7860/JCDR/2020/43000.13408
Year : 2020 | Month : Jan | Volume : 14 | Issue : 01 Full Version Page : OC01 - OC05

Presenting Features and Clinical Profile of Scrub Typhus Fever Cases in Adult Patients Admitted in a Tertiary Care Hospital in Puducherry, India

A Tumbanatham1, K Jayasingh2, S Lokesh3, Selvaraj Stephen4

1 Associate Professor, Department of General Medicine, Mahatma Gandhi Medical College and Research Institute, Sri Balaji Vidyapeeth (Deemed To be University), Puducherry, India.
2 Former Professor and Head, Department of Medicine, Mahatma Gandhi Medical College and Research Institute, Sri Balaji Vidyapeeth (Deemed To be University), Puducherry, India.
3 Head, Department of Medicine, Mahatma Gandhi Medical College and Research Institute, Sri Balaji Vidyapeeth (Deemed To be University), Puducherry, India.
4 Professor, Department of Microbiology, Mahatma Gandhi Medical College and Research Institute, Sri Balaji Vidyapeeth (Deemed To be University), Puducherry, India.

NAME, ADDRESS, E-MAIL ID OF THE CORRESPONDING AUTHOR: Dr. A Tumbanatham, Associate Professor, Department of General Medicine, Mahatma Gandhi Medical College and Research Institute, Sri Balaji Vidyapeeth (Deemed To be University), Puducherry, India.
E-mail: tumbanatham@gmail.com


The infection of scrub typhus is caused by the bite of infected chiggers and the clinical manifestation of scrub typhus is characterised by the presence of fever, headache and body pain and rarely can causes rashes. There is paucity of information regarding the clinical presentation and the pathophysiological manifestation of scrub typhus infection, especially in tropical regions in Southern India.


To determine the clinical profile and manifestation of scrub typhus infection among adults in Puducherry, India.

Materials and Methods

This retrospective study was conducted on data of 79 IgM Immunochromatography (ICT) positive for scrub typhus patients, who were admitted and treated in 2015 in the study institution. Particulars regarding the clinical presentation, laboratory parameters and course in the hospital were documented from the medical records. Chi-square test was carried out to look for statistical significance between clinical and demographic parameters.


Fever was the predominant symptom (49.4%) followed by headache (38%) and cough (19%). Eschar was present in 16.4% of the participants, and it was predominantly located in hypochondrium, anterior abdominal wall and sacral region (15.4%). About 17.7% of the participants had abnormal respiratory signs, of which bilateral crackles with ronchi was the most common sign (64.4%). While most common complication was gastrointestinal (18.1%); multi-organ involvement was present in 11.4% of the participants. Participants >40 years of age increasingly presented with symptoms of Central Nervous System compared to younger age group (p<0.05).


The features of febrile illness with low total count and thrombocytopenia with high index of suspicion for scrub typhus may prevent mortality due to multiorgan failure by early institution of treatment.



Scrub typhus is a bacterial infection caused by Orientia tsutsugamushi. The infection of scrub typhus is caused by the bite of infected chiggers and the clinical manifestation of scrub typhus is characterised by the presence of fever, headache and body pain and rarely can cause rashes. Scrub typhus is mite borne rickettsiosis and is an endaemic infection in Asia specific region and is said to affect about 1 billion people [1]. Although this zoonotic infectious disease is more prevalent in mite infested areas, human beings get in contact with these mites as a result of recreational, occupational or agricultural exposure. During the pre-antibiotic era, scrub typhus was considered a lethal disease and after the advent of several antibiotics, especially doxycycline, the infection is largely controlled.

Scrub typhus has been present in Southeast Asia since World War II, however, there has been a resurgence of the infection in India in the last few decades [2]. Although, scrub typhus is prevalent in Indian sub-continent there are very few evidences of its presence in other parts of the country especially in North and East India. There is a very low level of awareness regarding the scrub typhus infection among doctors and therefore the index of suspicion among the clinicians, especially private medical practitioners in rural areas is far lower for scrub typhus infections [3]. There are however many cases reported among the paediatric age group while very few cases are documented in the adult populations. In addition, studies have reported an overall mortality between 7 and 30% for scrub typhus which is fairly higher compared to other infections and zoonotic diseases [4].

Apart from the increased mortality, the scrub typhus infection is also associated with the high risk of complications namely multiorgan dysfunction. There are studies which have documented impairment of the nervous system and renal system but there are few cases which have documented multiorgan dysfunction as a consequence of acquired scrub typhus infection [5].

There is paucity of information regarding the clinical presentation and the pathophysiological manifestation of scrub typhus infection, especially in tropical regions in Southern India. Therefore, this study was carried out in order to substantiate the clinical manifestation of this infection so as to sensitise the primary clinicians regarding the scrub typhus infections. The significance of evaluating scrub typhus in tropical countries like India stems from the fact that the disease is widely distributed in the tsutsugamushi triangle which comprises of various countries in the Asia Pacific region including Japan, China, India, Pakistan, Afghanistan and southern parts of Russia [6]. This study was carried out to determine the clinical profile and manifestation of scrub typhus infection among rural adults in Puducherry, India.

Materials and Methods

This Retrospective study was conducted in the Department of General Medicine in a tertiary care hospital from January 2015 to December 2015. The case records of all the adults who were admitted with scrub typhus infection during the study period were included in the study, after due approval from the institutional ethical board. All the procedure have been followed according to the Deceleration of Helsinki.

Inclusion Criteria

Adult patients who were positive for IgM antibody for scrub by Immunochromatography (ICT).

Exclusion Criteria

Clinical confirmation of any other co-existing febrile illness like malaria, dengue or any other tropical diseases, children <18 years of age, case records with insufficient/incomplete medical data.

Sample Size and Sampling Technique

A total of 94 cases were recorded in the year 2015. Among the 94 cases, immunochromatography for IgM positivity was present in 86 cases. Out of the 86 cases, 7 cases were excluded due to incomplete data. Analysis was carried out on a total of 79 cases.

Data Collection Tools

Data were collected from the medical records departments. The background profile regarding age and sex of the individuals were documented. The clinical presentation, physical examination and laboratory parameters were documented. The course in the hospital in terms of the duration of hospital stay, treatment given and patient outcomes were also documented.

Statistical Analysis

Data were entered and analysed using SPSS version 15.0 software. The clinical presentation was expressed in terms of presentations. Chi-square test was used to analyse the statistical significance of demographic characteristics with clinical manifestations. Independent sample t-test was used to determine the association between the means of the parameters and the clinical manifestation. A p-value <0.05 was considered statistically significant.


This study was carried out among 79 hospital admissions. Majority of the participants were males (60.8%) and were less than 40 years of age (55.7%). Fever was the predominant symptom (49.4%) followed by headache (38%) and cough (19%) [Table/Fig-1].

Clinical symptoms.

CharacteristicsFrequency (N=79)Percentage (%)
Primary symptoms*
Generalised body pain1519.0
Other symptoms*
CNS symptoms1620.3
Swelling of feet11.3
Joint pain22.5
Abdominal symptoms
Type of abdominal symptoms (n=30)
Loose tools723.3
Abdominal distension13.3
Pain abdomen710.1
Epigastric pain13.3

*the figures will not total to 100

Almost all the participants had clinical hyperthermia (98.7%), about 17.7% of the participants had abnormal respiratory signs, splenomegaly was present in 12.7% of the participants [Table/Fig-2].

Clinical findings.

S. No.ParameterFrequencyPercentage
1Vital signs
2General examination
Pedal oedema22.5
2.1Eschar location (n=13)
Left axilla17.7
Right hypchondrial region215.4
Right elbow17.7
Right axilla17.7
Left hypchondrium215.4
Anterior abdominal wall215.4
Sacral region215.4
Left inguinal region17.7
Right iliac fossa17.6
3Systemic examination
Abnormal signs of cardiovascular system00
Abnormal signs of respiratory system (RS)1417.7
3.1Specific respiratory system signs (n=14)
Bilateral crackles and rhonchi964.4
Bilateral wheeze present321.4
Right lower zone pneumonia17.1
Bilateral crepitations and right side pleural effusion17.1
3.2Specific abdomen signs1721.5
3.3Specific signs of Central Nervous System (CNS)67.6
Agitate and restless350.0
Features suggestive of meningo-encephalitis116.6
Auditory hallucination116.7

Among the study participants, low total white blood cell counts were seen in 63.3% and elevated total white blood cell counts were seen in 17.7% of the participants, while thrombocytopenia was present in 49.4%. Abnormal urine analysis was seen in 3.8% of the participants. About 44.3% of the participants have urine albumin in traces. Chest radiograph was largely normal and only one participant showed presence of bilateral nodular shadows [Table/Fig-3].

Laboratory findings.

CharacteristicsFrequency (N=79)Percentage (%)
Total count
Low (<4000 cells/cumm)5063.3
Normal (4000-11000 cells/cumm)1417.7
High (>11000 cells/cumm)1519.0
Platelet count
Thrombocytopenia (<150,000 cells/mcL)3949.4
Normal (100,000-450,000 cells/mcL)4050.6
Urine analysis*
Arterial Blood Gas (ABG)
Chest radiograph
Bilateral nodular shadows11.3

*one or more of abnormal urine analysis including proteinuria, glucosuria, presence of pus cells, red blood cells

The distribution of laboratory parameters are shown in [Table/Fig-4]. The predominant parameters that were elevated were differential white blood cell counts and alkaline phosphatase levels. All the participants received doxycycline either alone (96.2%) or in combination with ceftriaxone or azithromycin. Majority of the participants were discharged within 6 days (48%), with a mean duration of hospitalisation of 5.6 days while 27.9% of the patients had complications. While most common complication was gastrointestinal (18.1%), multiorgan involvement was present in 11.4% of the participants [Table/Fig-5]. The mean values of various laboratory parameters estimated are given in [Table/Fig-6].

Distribution of laboratory parameters.

Course in the hospital.

Antibiotic used
Cephotriaxone and doxycycline11.3
Doxycycline and azithromycin22.5
Duration of hospitalisation (in days)
Types of complications (n=22)
Neuropsychiatric; electrolyte imbalance14.5
Gastrointestinal; haematological29.1
Gastrointestinal; renal14.5
Electrolyte imbalance14.5
Renal; respiratory14.5
Haematological; renal14.5
Multi organ14.5
Hepatic; renal29.1
No of organs affected
Multi organ911.4

Mean values of the parameters.

Pulse (beats/minute)85.39.4
Total count7679.703372.6
Platelet count (lacs/cumm)1.972.3
Haemoglobin (g/dL)10.61.7
Urea (mg/dL)31.026.8
Creatinine (mg/dL)1.00.8
Total bilirubin1.10.9

This study found a significant difference in the presence of CNS symptoms with respect to the age of the participants. Participants aged >40 years were more at risk of CNS symptoms (31.4%) compared to those aged <40 years (11.4%). The observed difference was statistically significant (p<0.05) [Table/Fig-7]. A significant difference in the total whole blood cell count was observed with respect to the sex of the participants. Females had increased risk of abnormal counts compared to males. The observed difference was statistically significant (p<0.05) [Table/Fig-8]. There was also a significant difference in the laboratory parameters pertaining to renal functions, with respect to the presence of multi-organ involvement. The observed difference was statistically significant (p<0.05) [Table/Fig-9]. However, there was no mortality among the study participants due to scrub typhus.

Association between demographic characteristics and significant symptoms.

ParametersCNSN (79)Chi squarep-value
Age (years)
<405 (11.4)39 (88.6)444.80.02
>4011 (31.4)24 (68.6)35

Association between demographic parameters and laboratory findings.

ParametersTotal countN (79)Chi squarep-value
Female23 (74.2)1 (3.2)7 (22.6)317.30.02
Male27 (56.3)13 (27.1)8 (16.7)48

Association between complication with multisystem involvement and clinical parameters.

FactorN=79MeanSDt-value95% CIp-value
Urea9-0.3960.527-2.877-0.670 to -0.1220.005
Creatinine81.3750.517-3.720-0.762 to -0.2300.0001


In this study majority of the participants belonged to less than 40 years of age. Another predominant symptom observed in our study was headache and apart from these symptoms, abdominal symptoms were also present in 38% of the participants. In a study done by Jain D et al., the mean age of the participants was 38 years, similar to this study. Abdominal symptoms were present in 33% of the participants, similar to this study (38%) [5]. In another study done by Narvencar KPS et al., the abdominal symptoms were present in 46.7% of the participants [7]. Eschar was present in 16.4% of the study participants, similar to the study observed by Zhang L et al., [8]. In addition 17.7% of the participants had respiratory signs including bilateral crackles. Moreover, splenomegaly was also present in 12.7% of the participants. Studies have documented that presence of eschar is essential in determining the prognosis of patients with scrub typhus infections. Patients without eschar are proven for increased risk of severe complications. However, this correlation could not be explored in the index study due to paucity of information. Identification of preferences sites of eschar formation is also important in order to detect it early and address at earliest stages [9].

It is essential to document the incubation period and duration between onset of fever and the onset of other symptoms was clinically important. The incubation period is documented from time of bite by infected chiggers to appearance of fever. However, incubation period was not documented in the present study. In a study done by Takhar RP et al., three patients were diagnosed in the second week and had manifestation of fever and other manifestation of scrub typhus two weeks after the onset of fever [3]. However, several studies reported a variation in the presentation of eschar. Some Indian researchers like Vivekanandhan M et al., documented the prevalence of eschar to be around 45% [10]. It is worthwhile noting that the diagnosis made in the above study was using Weil-Felix reaction which does not have established validity. In the index study, we used rapid diagnostic test ICT which although is not a gold standard Test like immunofluorescent or Enzyme-Linked Immunosorbent Assay (ELISA) but is a good tool for rapid diagnosis [11].

Scrub typhus is predominantly said to result in multi organ dysfunction. With more participants having low leucocyte counts and significant prevalence of thrombocytopenia, 27.9% of participants had complications of which majority of the complications were related to gastro intestinal system including hepatomegaly and renal involvement. However, multiple organs were affected in 11.4% of the present study participants. In another study 48.5% of the participants had more than three organ systems involve while 30% of the participants had about five organ dysfunctions during the hospital stay [3]. This difference could be due to the aggressive management and early presentation to the health care facility in index study; however, there is a need for substantial evidence to support the difference. The common complications involve circulatory collapse, Acute Respiratory Distress Syndrome (ARDS), haematological complications and electrolytes imbalances as seen in almost all participants in the study. Some studies have documented other extraneous complications including meningoencephalitis, gastrointestinal bleeding, acute renal failure, hearing impairment, opsoclonus and pancreatitis [3,12,13]. While most of the infections were easily controlled by doxycycline antibiotic, some of the patients required ceftriaxone and azithromycin combinations. Antimicrobial resistance was reported in several Asian countries like Thailand etc., [14]. Moreover, refractory cases have also been reported in other countries, with an emerging threat of drug resistance [15].

In this study, present athours found statistically significant relationship between the age of the participants and presence of CNS symptoms. There was an increase predisposition to CNS symptoms including lethargy etc., among patients who were >40 years of age compared to those <40 years of age. Moreover, there was a variation in total count levels with respect to the gender of the participants. Females were more prone for an increased variation while males were found to have near normal total count levels. There are few studies which have correlated the age and organ specific complications for scrub typhus.

We did not report any mortality from scrub typhus due to the presence of early case management and adequate antibiotic coverage. The mortality rate from scrub typhus has been ranging from 7-30% [16] all over the world with about 30% in Taiwan [17] and 10% in Korea [18]. In India studies done by Takhar RP et al., documented mortality rate of 21.2% [3]. It was higher compared to studies done by Mahajan SK et al., with the mortality of 14.2% and Kumar K et al., with the mortality of 17.2% [4,19]. The comparison with similar published studies is given in the [Table/Fig-10] [3,5,7,10,20-22].

Comparison of clinical and laboratory findings of the present study with published literature [3,5,7,10,20-22].

StudyClinical symptomsClinical signsLaboratory investigation
ParametersPercentage (%)ParametersPercentage (%)ParametersPercentage (%)
Present studyFever49.4Eschar16.4Raised serum creatinine16.5
Abdominal symptoms38Lymphadenopathy8.9Thrombocytopenia49.4
Multiple organs affected11.4
Girija S et al., [20]Fever100Eschar4Elevated transaminases20
Cough40Rash3Raised serum creatinine80
Inamdar S et al., [21]Fever79.5Eschar75.5--
Abdominal pain56Lymphadenopathy52.5
Varghese GM et al., [22]Fever100Eschar55Elevated transaminases72.5
Altered sensorium24.6Raised serum creatinine12.9
Vivekanandan M et al., [10]Fever100Eschar46Elevated transaminases95.9
Cough40Altered sensorium20Raised serum creatinine13
Jain D et al., [5]Abdominal symptoms33Eschar12.82Thrombocytopenia46.2
Narvencar KPS et al., [7]Abdominal symptoms46.7Eschar13.3Raised serum creatinine33.3
Takhar RP et al., [3]Fever100Eschar12.1Mortality rate21.2
Cough48.5Lymphadenopathy18.2Raised creatinine51.5
Multiple organ dysfunction48


Being a retrospective study the active burden of the infection in the population could not be ascertained. A long term follow-up study on large sample is required to analyse the clinical extent of involvement of the disease in order to devise preventive strategies.


Scrub typhus is a common infection of the tropics and is often labelled as pyrexia of unknown origin. This study has documented the presence of significant correlation between age of the participants and clinical presentation of symptoms of central nervous system. This study also elucidated a significant association between age at presentation and symptoms of central nervous system. It is therefore essential to note that the index of suspicion should be high for scrub typhus fever when the patient presents with fever, thrombocytopenia and multi organ involvement in order to prevent mortality.

*the figures will not total to 100*one or more of abnormal urine analysis including proteinuria, glucosuria, presence of pus cells, red blood cells


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