Short Report

Outbreak of scrub typhus in North India: a re-emerging epidemic

Tropical Doctor 2014, Vol. 44(3) 156–159 ! The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0049475514523761 tdo.sagepub.com

Sunil Sethi1, Amber Prasad2, Manisha Biswal3, Vinay Kumar Hallur4, Abhishek Mewara4, Navneet Gupta5, Shipra Galhotra4, Gagandeep Singh4 and Kusum Sharma6

Abstract Scrub typhus is re-emerging in India. We describe an outbreak of 45 cases from our tertiary care center in north India. This outbreak included city dwellers who had no history of travel to hilly areas. The classical feature of scrub typhus, the eschar, was also noted rarely in these patients. The changing epidemiology of scrub typhus should be kept in mind while attending patients with acute febrile illness.

Keywords Orientia tsutsugamushi, outbreaks, scrub typhus

Introduction Scrub typhus is an acute febrile syndrome caused by Orientia tsutsugamushi and transmitted by the bite of the chigger of the mite belonging to the family Trombiculidae of genus Leptotrombidium.1 It is distributed mainly in the rural areas of the ‘tsutsugamushi triangle’ limited by northern Japan, eastern Australia, and eastern Russia that includes the Indian subcontinent, western Russia, China, and the Far East.2 People affected are mainly those engaging in agricultural, recreational, or military activities that bring them in contact with mite infested habitats, or travelers returning from endemic regions. Scrub typhus seems to be remerging in India with several states reporting outbreaks in the last few years.3–10 Here, we describe an outbreak from our hospital and summarize the picture of scrub typhus epidemics in India in the past few years.

Short report Acute phase sera of a total of 1,053 patients with acute febrile illness suspected to be suffering from scrub typhus were subjected to Weil Felix agglutination test. A titre of >320 was recorded in 110 patients’ sera, 51 of which were tested by a commercial IgM ELISA kit (InBios International, Seattle, WA, USA). IgM ELISA was found positive in 45 of these patients who were considered positive. A detailed clinical history of these patients was obtained. The majority of the

patients were from the state of Haryana, followed by Himachal Pradesh, Chandigarh, and UP (Figure 1). Around 62.2% (28/45) were male patients and 37.8% (17/45) female patients; 55.5% (25/45) patients were from the pediatric age group. The maximum number of cases presented during the month of September (Figure 1). The commonest complaint was fever present in all the patients (45/45; 100%), followed by vomiting (27/45; 60%), hepatomegaly (22/45; 48.9%), headache (17/45; 37.8%), dyspnea (16/45; 35.5%), chills (5/45; 11.1%), altered sensorium (10/45; 22.2%), and splenomegaly (9/45; 20%). The commonest combinations of symptoms were fever with shortness of breath or 1 Additional Professor, Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Chandigarh, India 2 Senior Resident, Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Chandigarh, India 3 Assistant Professor, Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Chandigarh, India 4 Senior Resident, Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Chandigarh, India 5 Deputy Director, National Center for Disease Control, New Delhi, India 6 Associate Professor, Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Chandigarh, India

Corresponding author: Sunil Sethi, Department of Medical Microbiology, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India. Email: [email protected]

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Figure 1. Trend of scrub typhus outbreak and state wise distribution of cases (y-axis represents number of cases). Tricity: Chandigarh, Mohali and Panchkula.

vomiting or headache. Thrombocytopenia was present in 28.9% (13/45) patients, while eschar was present only in two (4.4%) patients (forearm and abdomen). Twenty-three (51%) patients developed complications, the most common of which was meningoencephalitis (27%), followed by acute respiratory distress syndrome (11%), acute renal failure (9%), and shock (4%). There was mortality in two (4.4%) patients, both in the pediatric age group. Scrub typhus has been described as a resurgent infectious disease in India, with several reports of outbreaks from different parts of the country namely the north east regions, Sikkim, Goa, Tamil Nadu, Puducherry, Haryana and Himalayan regions (Table 1).3–10 This outbreak occurred during the rainy season (June to October) in contrast to the other outbreaks from India where it has been described during winters in south India and autumn in the Himalayas.7,10 However, this is in agreement with other studies where scrub typhus outbreaks have occurred most frequently during the rainy seasons, since rains coincide with maximum propagation of trombiculid mites.6 A recent increase in prevalence of scrub typhus in some Asian countries has been documented and may be attributed to urbanization of rural areas. We found that an unusually large number of patients (64%) were residents of urban areas. Another interesting finding was the occurrence of scrub typhus among residents of cities like Chandigarh, Mohali, and Panchkula, also known as Tricity, and other areas of Punjab and Uttar Pradesh, where scrub typhus has never been reported previously. The reason for the emergence of scrub typhus in these regions is not known, though, climatic changes, agricultural practices conducive for mite

breeding, migration of infected persons from rural to urban areas, and an increased awareness among clinicians may be attributed to this rise. All our patients had fever for duration of more than 1 week which helped to differentiate it from viral fever which is common during the rainy season. Many patients also had non-specific complaints pertaining to the respiratory, gastrointestinal, or central nervous system. The number of patients who presented with altered sensorium and presence of rashes were consistent with other recently reported outbreaks. Symptoms like cough and myalgia were reported in a fewer number of patients as compared to other studies.7 Eschar, once thought to be an important sign of scrub typhus, was present only in two patients. The rarity of presentation with an eschar is increasingly being recognized in Southeast Asian patients. Hence, even in the absence of eschar in a case of undifferentiated fever, physicians should be on an alert for scrub typhus, especially in residents of/or travelers returning from south Asia. The mortality was low with only two deaths reported which could be attributed to prompt institution of doxycycline (azithromycin was used in three pregnant women). Among the gold standard tests for the diagnosis of scrub typhus, ELISA was used in this outbreak. Other confirmatory assays like indirect immunofluorescence antibody test and indirect immunoperoxidase test are not available in our country and isolation of the organisms in animal or cell cultures is limited by lack of containment facility as well as expertise in handling these high-risk group pathogens. The most commonly used diagnostic assay in developing countries is Weil Felix agglutination test, which is a heterophile antibody test.

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52

65

ELISA

2012

NA, not available.

IgM

Weil Felix,

IgM ELISA

PCR

IgM ELISA,

PCR

children

25

20 adults,

Adults

Adults

NA

children

ELISA

IgM ELISA,

27

IgM

to October

Present study; June 45

Jan. 2012

Feb. 2011 to

Puducherry;

to Oct. 2010

Aug. 2009

Vellore, Tamil Nadu; 154

2010-2011

Nagaland;

Pradesh,

Assam, Arunachal

to Dec. 2011

36 adults,

Adults

28:17

33:32

81:73

NA

42:21

5:10

ratio

17.8%

NA

1.3%

NA

22.2%

53.3%

Rashes

4%

20%

55%

11.1%

19%

13.3%

Eschar

60%

NA

53.9%

38.9%

15.9%

100%

vomiting

37.8%

60%

42.9%

27.7%

25.4%

NA

Headache

22.2%

26.1%

24.6%

11.1%

4.7%

6.7%

sensorium

Altered

13.3%

NA

37%

NA

NA

46.7%

Cough

20%

27.7%

32.5%

NA

22.2%

80%

arthalgia

Myalgia/

11.1%

12.3%

NA

NA

NA

13.3%

adenopathy

Lymph

48.9%

41.8%

NA

11.1%

30%

60%

megatly

Hepato

20%

23.1%

NA

16.6%

28.5%

26.7%

megaly

Spleno

4%

20%

26.6%

NA

NA

53%

bilurubin

serum

raised

26%

63%

NA

NA

1.6%

40%

cytopeneia

Thrombo

8.8%

3%

12.9%

44%

17.4%

33%

failure

Renal

4.4%

0%

7.8%

NA

1.6%

33.3%

Mortality

Narvencar

Reference

Sethi et al.

et al., 2013

Vishwanathan

2013

Varghese et al.,

2012

Khan et al.,

2013

et al., 2012

Weil Felix,

IgM ELISA

Age group

Nausea and

Gurung et al.,

63

15

Goa; June 2009

diagnosis

Male:female

Sikkim; Jan. 2011

cases

of study

Method for

Jaundice/

to Oct. 2010

Confirmed

Place; period

Table 1. Demographic, clinical, and laboratory parameters of recent outbreaks of scrub typhus reported from India.

Sethi et al.

159

Though less sensitive and specific, a high titre of 320 in a single sample is considered to be diagnostic. This test is economical and easy to perform hence useful for screening, however, should be used only in conjunction with a confirmatory test. In conclusion, there is an increasing prevalence of scrub typhus in India and it is now occurring in areas where it was not known previously. Of particular importance is the disease occurring in residents of urban areas of the plains who have no history of travel to hilly areas. Physicians should therefore be more aware of this entity and should consider it in the differential diagnosis of acute febrile illness even when the presentation of patients is not classical of scrub typhus. Declaration of conflicting interests None declared.

Funding This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.

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3. Khan SA, Dutta P, Khan AM, Topno R, Chowdhury P and Mahanta J. Re-emergence of scrub typhus in northeast India. Int J Infect Dis 2012; 16: e889–890. 4. Gurung S, Pradhan J and Bhutia PY. Outbreak of scrub typhus in the North East Himalayan region-Sikkim: an emerging threat. Indian J Med Microbiol 2013; 31: 72–74. 5. Narvencar KP, Rodrigues S, Nevrekar RP, Dias L, Dias A, Vaz M, et al. Scrub typhus in patients reporting with acute febrile illness at a tertiary health care institution in Goa. Indian J Med Res 2012; 136: 1020–1024. 6. Varghese GM, Janardhanan J, Trowbridge P, Peter JV, Sathyendra S, Thomas K, et al. Scrub typhus in South India: clinical and laboratory manifestations, genetic variability, and outcome. Int J Infect Dis 2013; 17: e981–987. 7. Prakash JA, Kavitha ML and Mathai E. Nested polymerase chain reaction on blood clots for gene encoding 56 kDa antigen and serology for the diagnosis of scrub typhus. Indian J Med Microbiol 2011; 29: 47–50. 8. Viswanathan S, Muthu V, Iqbal N, Remalayam B and George T. Scrub Typhus Meningitis in South India - a retrospective study. PLos One 2013; 8: e66595. 9. Chaudhry D, Garg A, Singh I, Tandon C and Saini R. Rickettsial diseases in Haryana: Not an uncommon entity. J Assoc Physicians India 2009; 57: 334–337. 10. Sharma A, Mahajan S, Gupta ML, Kanga A and Sharma V. Investigation of an outbreak of scrub typhus in the himalayan region of India. Jap J Infect Dis 2005; 58: 208–210.

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Outbreak of scrub typhus in North India: a re-emerging epidemic.

Scrub typhus is re-emerging in India. We describe an outbreak of 45 cases from our tertiary care center in north India. This outbreak included city dw...
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