Journal of Applied Hematology

: 2020  |  Volume : 11  |  Issue : 4  |  Page : 180--183

Clinicohematological, treatment, and outcome profile for scrub typhus: Observations from a tertiary care center

Thomas George1, Ramakrishna Pai Jakribettu2, Soniya Abraham1, Michael L J. Pais1, Mohammed Adnan1, Manjeshwar Shrinath Baliga1,  
1 Father Muller Research Centre, Mangalore, Karnataka, India
2 Department of Microbiology, Father Muller Medical College Hospital, Mangalore, Karnataka, India

Correspondence Address:
Dr. Ramakrishna Pai Jakribettu
MES Medical College, Perinthalmanna - 679 338 Kerala


BACKGROUND: Scrub typhus, an acute febrile illness, is one of the emerging and re-emerging infectious diseases in India. This study was undertaken to assess the clinicohematological, treatment, and outcome profile of the patients diagnosed with scrub typhus at the clinical microbiology department of a tertiary care teaching hospital in Coastal Karnataka, India. MATERIALS AND METHODS: This was a retrospective study conducted with patients diagnosed as scrub typhus between January 2014 and December 2017. The demographic, clinical, laboratory, treatment, and outcome profile of these patients were noted and analyzed by Student's t-test. A P < 0.5 was considered statistically significant. RESULTS: A total of 146 patients were included in the study. The males were more infected than females, and people in the age group of 51–60 years were affected the most. Fever (139, 95.2%) was the most common symptom. Eschar was seen in only 52 (34.89%) patients. Anemia, leukocytosis, neutrophilia, lymphocytopenia, eosinophilia, monocytosis, thrombocytopenia, and raised erythrocyte sedimentation rate were statistically significant in scrub patients. The hepatic and renal indicators were also deranged. All patients were treated with doxycycline, and platelet was transfused in 7 (4.8%) patients. Among the seven dead patients, there were significant eosinopenia and deranged renal parameters compared to the survived patients. CONCLUSION: In endemic area, when a middle-aged individual presents with fever and leukocytosis with thrombocytopenia with or without eschar, scrub typhus should be considered as a differential diagnosis and empirical therapy started.

How to cite this article:
George T, Jakribettu RP, Abraham S, J. Pais ML, Adnan M, Baliga MS. Clinicohematological, treatment, and outcome profile for scrub typhus: Observations from a tertiary care center.J Appl Hematol 2020;11:180-183

How to cite this URL:
George T, Jakribettu RP, Abraham S, J. Pais ML, Adnan M, Baliga MS. Clinicohematological, treatment, and outcome profile for scrub typhus: Observations from a tertiary care center. J Appl Hematol [serial online] 2020 [cited 2021 Mar 3 ];11:180-183
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Scrub typhus or chiggerosis is one of the emerging and re-emerging rickettsial infections in the Indian Subcontinent.[1] Reports suggest that annually, around one billion people living in the endemic area are at risk of the infection and among which one million get infected.[2] Scrub typhus, being a differential diagnosis for acute febrile illness, is usually under diagnosed, due to nonspecific symptoms, less suspicious by clinicians, and limited diagnostic facilities, especially in the primary healthcare facilities, where most of the treatment is given in India.

From an epidemiological perspective, scrub typhus is endemic in the global map known as “tsutsugamushi triangle,” which is densely populated, extending from Afghanistan and Pakistan in the West, Northern Japan and Eastern Russia in the North, and up to New Guinea and Northern Australia in the South.[3] This area provides all the prerequisites for the maintenance of Orientia in nature, i.e., the vector trombiculid mites, reservoir small rodents, and scrub vegetation.[4] The vector mites circulate the pathogens among the small rodents[5] and man is accidentally exposed to the infested rodents at residence, farming, or trekking in the the endemic areas.[6] On inoculation, during the blood meal by the mites, these pathogens get carried into vascular system by the macrophages infecting the endothelial cells. They survive in the cytoplasm of the endothelium releasing cytokines, which causes fluid leakage into interstitium.[4]

In India, cases have been reports mainly from Rajasthan, Jammu and Kashmir, Nagaland, Manipur, Sikkim, Puducherry, Tamil Nadu, and recently from Karnataka and Kerala.[2] India, being endemic to other tropical diseases such as dengue, malaria, leptospirosis, typhoid, and chikungunya, scrub typhus needs to be differentiated. The incubation period may vary from 5 to 20 days (median 10–12 days). The site of inoculation, i.e., the bite of chigger, is usually unnoticed; however, due to localized itching, it gets noticed, seen mainly in the neck, axilla, abdomen, and chest. It is usually presented as a triad of eschar, regional lymphadenopathy, and maculopapular rash, which is seen in around 50% of the cases.[4],[7] If not diagnosed and treated appropriately, the patient may have fatal complications such as hemorrhage due to thrombocytopenia and multi-organ involvement, especially acute renal failure. The case fatality rate has been reported to be 30%–45% in untreated cases.[8]

In the initial phase of the disease, the laboratory parameters will be normal but get deranged later. Most of the studies have noticed neutrophilia and lymphocytopenia.[9],[10] The hepatic and renal biochemical parameters may also get deranged in severe cases.[9],[10] In this study, we have attempted at understanding the complete profile (clinical symptoms, laboratory details, treatment, and outcome) in people affected with scrub typhus and compared the details with age-matched healthy individuals.

 Materials and Methods

This was a retrospective study conducted at the Department of Clinical Microbiology at a tertiary care teaching hospital in Coastal Karnataka, India. The study was undertaken following approval by the institutional ethics committee (FMIEC/345/2018). All patients above the age of 18 years, who got admitted with a history of fever and suspicion of scrub typhus, from January 2014 to December 2017, were included in the study. Probable case was defined as the patient presenting with acute febrile illness with or without eschar, headache, lymphadenopathy, and multi-organ involvement (liver, lung, and kidney) with titers of ≥ 1:80 in OX-K antigen by Weil-Felix test. Patients with positive result for antibodies were included in patients group. All the clinical and laboratory profile and treatment details during the study time period were collected. The demographic details were categorized into frequency, while the hematological and biochemical data were calculated to obtain mean ± standard deviation (SD). In addition to the scrub-positive cases, we also collected the hematological and biochemical data of age-matched healthy individuals coming for a routine health check-up and used as control. All these details are represented in the tables. For overall comparison, the results were compared as healthy individuals and scrub typhus patients and subjected to unpaired Student's t-test. A P = 0.05 was considered statistically significant.


A total of 146 people diagnosed with scrub typhus patients, and 58 healthy individuals who had come for health check-up during the study period were included in the study. Among the scrub typhus patients, 95 (65.07%) were male and 51 (34.93%) female, and most patients (36, 24.6%) were in the age group of 51–60 years [Figure 1]. Among the patients studied, fever (139, 95.2%) was the most common symptom, followed by eschar (52, 34.89%) and headache (38, 26%) [Table 1].{Figure 1}{Table 1}

The hematological parameters showed that scrub typhus patients had anemia, leukocytosis, neutrophilia, lymphocytopenia, eosinophilia, monocytosis, thrombocytopenia, and raised erythrocyte sedimentation rate (ESR), which was statistically significant [Table 2]. Among the hepatic biochemical parameters, total bilirubin and the liver enzymes were significantly elevated [Table 2]. The blood urea and serum creatinine were also significantly raised among the patients compared to healthy individuals [Table 2]. All patients were treated with doxycycline for a duration for 7–10 days and other supportive therapies such as intravenous fluid, antipyretics, and analgesics, accordingly, of which seven succumbed to disease. When all the laboratory parameters were compared among the dead and alive scrub typhus patients and the deceased patients, there was significantly raised blood urea and serum creatinine with eosinopenia. Among the seven dead patients, complications which lead to mortality are Acute respiratory distress syndrome (ARDS) (3), sepsis (2), acute kidney injury (1), and encephalitis (1).{Table 2}


Scrub typhus is one the under-diagnosed diseases and is reported as emerging infectious disease in India.[11] It is one of the diseases to be considered for a differential diagnosis for the acute febrile illness as patients may present with varying clinical features from fever to complicated meningoencephalitis and bleeding tendency. Studies have also shown that PCR-based assays have shown that scrub typhus accounts for nearly 20% of all cases of pyrexia of intermediate duration in endemic areas.[12]

A systemic review involving 89 (1910–2014) patient series, from various countries, mainly in tsutsugamushi triangle studied 19,644 patients; fever was the most common symptom, followed by headache, conjunctival congestion, myalgia, and cough.[10] Similarly, in our study, the most common symptom was fever (95%), followed by headache (26%), cough (24.6%), vomiting (18.5%), and body ache (17.8%), and around 3.5% of the patients have presented with altered sensorium also. Even though eschar is pathognomonic, we observed it in 11 patients (7.53%), but it has been reported in 13.1%–86.5% of cases.[13],[14],[15]

The laboratory parameter was deranged mainly the leukocytosis and hyperuremia in various studies,[10] similar to our study. In various Indian studies, leukocytosis and thrombocytopenia have been reported;[9],[13],[16] in addition, we have also observed anemia, neutrophilia, lymphocytopenia, eosinophilia, monocytosis, and raised ESR. Similarly, the liver enzymes were also significantly deranged in our study.[9],[13],[16]

The sequence of the pathogenesis by Scrub is as follows; the pathogen infects the host, enters the endothelial cells and proliferates. Concomitantly, the infected endothelial cells will trigger the release various pro-inflamatory cytokines and initiate damage to the endothelial lining and lead to fluid leak. The histopathological examination of the lesions has demonstrated vasculitis and perivascular inflammation, i.e., focal occlusive end-angitis, leading decreased blood supply mainly to end organs, especially lungs, kidneys, and brain.[17] Being a bacterial infection, leukocytosis and neutrophilia are explained and monocyte activation and proliferation as pathogen is phagocytosed and escapes killing due to phospholipase A in these cells.

Mortality of 10.7% was observed in patients below 30 years compared to 21.3% in patients above 30;[10] similarly, we had six of seven patients above 30 years. Higher mortality rate was seen in patients presenting with myocarditis, pulmonary symptoms, hemorrhage, and delirium,[10] whereas in our study, mortality was associated with ARDS, AKI, and encephalitis, possibly due to delayed presentation to the medical facility.


Scrub typhus is one of the important differential diagnoses among the patients with acute febrile illness in the Coastal Karnataka. It is suggested that when a patient from the endemic area, for Scrub typhus, presents with fever, eschar, headache along with anemia, leukocytosis, thrombocytopenia, raised renal (blood urea and serum creatinine) and hepatic (total bilirubin and liver enzymes) parameters, empirical therapy may be initiated to reduce morbidity and possible death.

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Conflicts of interest

There are no conflicts of interest.


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