Japanese Encephalitis: A common menace

Jeevitha Sivakumar, Akila V.Krishnan, Suresh Chelliah*

Department of Paediatrics Kauvery Hospital, Trichy Cantonment, India

Abstract

Japanese encephalitis is a vaccine-preventable disease, which kills about 13690 to 20400 of about 68000 clinical cases worldwide [1]. We present two cases, one clinical and another with positive serology and wish to stress the importance of vaccination.

Keywords: Japanese Encephalitis; Vaccination

Background

Japanese encephalitis is a leading cause of vaccine-preventable encephalitis in Asia. More than 99% of the infections are subclinical and cumulative exposure with age leads to a seroprevalence of 80% in adults [1].

We present two cases of Japanese encephalitis in our area.

Case Presentation

Case 1

A 13-years-age boy presented with complaints of vomiting, fever, headache for 3 days, and altered sensorium and tonic posturing of limbs for 1 day.

On examination, he was drowsy and had a low GCS (7/15), hypertonia and brisk deep tendon reflexes. Even after multiple anti-epileptic drugs, he had persistent posturing of limbs. He was intubated and ventilated. Investigations revealed normal blood counts with mildly elevated CRP. ABG analysis showed respiratory alkalosis. CSF analysis was done after anticerebral oedema measures showed lymphocyte predominant cell count and elevated CSF protein. Blood and urine culture and sensitivity were sterile.

MRI Brain showed T2/FLAIR hyperintensities involving bilateral thalamus, medial temporal lobe and bilateral parietal cortex with patchy areas of diffusion restriction, without contrast enhancement and diffuse cerebral edema, suggestive of viral encephalitis (Fig. 1). CSF for JE – IgM ELISA was positive and CBNAAT was negative. CSF culture was sterile. His sensorium and power improved with neuroprotective supportive care and he was weaned off from ventilator on day 4 of admission. He started tolerating oral feeds. He improved well and was discharged with oral antiepileptics.

Fig. 1. Symmetrical T2/FLAIR hyperintense signal noted in b/l thalami and left parietal cortex which are showing variable diffusion restriction on DWI images.

Case 2

A 12-years-old girl was brought with complaints of headache, high-grade fever, vomiting, sleep disturbance with loss of weight and loss of appetite for 15 days.

On examination, she was conscious, oriented with bilateral inguinal lymphadenopathy and had normal tone and power. She was treated with IV antibiotics and antiviral drugs for 9 days prior to admission. Investigations did before admission showed normal WBC count, and lymphocyte predominance with elevated ESR, SGOT and SGPT. MRI Brain done was normal.

Investigations done in our centre showed normal CSF analysis with hyponatremia, hypochloremia, normal liver transaminases. Blood and urine culture and sensitivity were sterile. During this time, serum JE IgM sent before admission was reported to be positive. CSF JE IgM sent was negative. Repeat serum JE IgM after 7 days of 1st report was also positive. Her symptoms improved with supportive care and she was discharged in stable status.

Discussion

Though the second child was found to be seropositive for JE virus, her clinical course was not conclusive of encephalitis. Documentation of vaccination was not available.

Japanese encephalitis is the largest worldwide cause of epidemic viral encephalitis [2]. It is a mosquito-borne disease belonging to genus Flavivirus and family Flaviviridae that affects equines, pigs and humans [3]. It is more common in areas where children are not routinely vaccinated, and with a slight preponderance in boys [2].

Attack rates in children (3-15-year age groups) are 5-10 times higher than in adults. Case fatality rate is 30% in those with disease symptoms. 20-30% of patients who survive suffer permanent intellectual, behavioural or neurological sequelae such as paralysis, recurrent seizures or the inability to speak [4].

The ability to clinically and serologically diagnose the disease depends on the quality of health care. Early diagnosis and prompt treatment of JE can reduce the mortality and morbidity (serious long-term neuropsychiatric sequelae) [5].

Conclusion

Effective Vaccination has brought down the incidence in this part of the country. However, eradication is not possible as with most ARBO viral illnesses. Vaccination should be considered where there is a suitable environment for the transmission.

Acknowledgements: The authors thank the ICU staff and colleagues for their assistance in management of the cases.

Author contribution: All the authors were involved in the management of the two children. Jeevitha S drafted the manuscript. Suresh C edited the manuscript and will stand as guarantor.

References

www.who.int/news-room/fact-sheets/detail/japanese-encephalitis
Feigin and Cherry’s textbook of paediatric infectious diseases.
Gulati BR, Singha H, Singh BK, et al. Serosurveillance for Japanese encephalitis virus infection among equines in India. J Veter Sci. 2011;12(4):341-5.
Saxena V, Dhole TN. Preventive strategies for frequent outbreaks of Japanese encephalitis in Northern India. J Biosci. 2008;33(4):505-14.
Erlanger TE, Weiss S, Keiser J, et al. Past, present, and future of Japanese encephalitis. Emerg Infect Dis. 2009;15(1):1.

Dr. Suresh Chelliah

Senior Consultant Paediatrician (Head – Academics)

Japanese Encephalitis: A common menace