Investigations of seasonal outbreaks of acute encephalitis syndrome due to Orientia tsutsugamushi in Gorakhpur region, India

Abstract

Gorakhpur division consisting of Gorakhpur and neighboring districts Deoria, Kushinagar and Maharajganj in Uttar Pradesh, India, have been witnessing seasonal outbreaks of acute encephalitis syndrome (AES) among children for the last three decades. Investigations conducted during 2005 identified Japanese encephalitis (JE) virus as an aetiology of AES. With the introduction of JE vaccination and other control strategies, the incidence of JE in the region declined, however, outbreaks of acute febrile illness with neurological manifestations continued to occur. Subsequent investigations identified Orientia tsutsugamushi, as the major aetiology of AES outbreaks in the region. This review details clinical, epidemiological, animal and entomological investigations conducted for AES due to O. tsutsugamushi during 2015 and 2017 in Gorakhpur region. Surveillance of acute febrile illness among children attending peripheral health facilities identified scrub typhus as an important aetiology of febrile illness during monsoon and post-monsoon months. Population-based serosurveys indicated high endemicity of scrub typhus. Entomological studies demonstrated natural infection of O. tsutsugamushi in small animal hosts and vector mites. Children acquired this infection through recent exposure to outdoor environment, while playing, or visiting fields or defecating in open fields. A few of the children with scrub typhus progress to develop CNS manifestations. Hence, early administration of appropriate antibiotics is crucial in preventing progression of AFI due to scrub typhus to AES. The investigations conducted by the multi-disciplinary team helped understand the transmission dynamics of scrub typhus in Gorakhpur division and recommend strategies for its control.

Epidemiology of scrub typhus and other rickettsial infections (2018-22) in the hyper-endemic setting of Mizoram, North-East India

“…In this study, the majority of the rickettsial infections were reported in monsoon and post-monsoon seasons, and is in line with several studies carried out in India [37][38][39]. Similarly, as reported earlier, the majority of the cases were in individuals involved in farming activities [39][40][41].…”

One Health activities to reinforce intersectoral coordination at local levels in India

“…The research studies often feature a multidisciplinary approach, combining social/epidemiological surveys with laboratory-based and/or economic investigations ( Table 1 ). For example, a transdisciplinary team of human and animal health researchers conducted several studies to identify Orientia tsutsugamushi , the causative agent of scrub typhus, as the major etiology of Acute Encephalitis Syndrome (AES) outbreaks in Gorakhpur region, India ( 36 ). These studies led to a better understanding of AES transmission in the region and recommendations for its control.…”

“…Intersectoral interactions at the village/sub-district level have occurred most frequently during disease outbreaks and have been observed across the country ( 22 , 36 , 41 , 42 ). These interactions often involve OH coordination and response between stakeholders at national, state, and district levels, usually with a top-down approach that directs, initiates, and supports response from lower-level stakeholders.…”

“…In a systematic review of studies from 18 states examining antimicrobial-resistant E. coli across India, only 10% (4 out of 38) conducted interdisciplinary samplingdefined as sampling from a combination of human, animal, or 1). For example, a transdisciplinary team of human and animal health researchers conducted several studies to identify Orientia tsutsugamushi, the causative agent of scrub typhus, as the major etiology of Acute Encephalitis Syndrome (AES) outbreaks in Gorakhpur region, India (36). These studies led to a better understanding of AES transmission in the region and recommendations for its control.…”

Association of Scrub Typhus in Children with Acute Encephalitis Syndrome and Meningoencephalitis, Southern India

“…† †Opsoclonus and myoclonus, choreoathetoid movements and hemiballismus, abnormal perioral movements, lip smacking, teeth grinding, and rapid eye blinking occurred in 1 patient each; tremors occurred in 2 patients. ‡ ‡Includes >1 of the following: truncal ataxia, gait abnormality, finger-nose incoordination, nystagmus, dysdiadochokinesis, and dysarthria.detecting IgM in serum samples only, Murhekar et al(6) observed good correlation between OD values for O. tsutsugamushi IgM in serum and CSF. They determined a cutoff OD value of 0.22 after testing CSF samples from 374 children <14 years of age with AES in Gorakhpur, Uttar Pradesh state, India…”