Investigation of japanese encephalitis virus as a cause of acute encephalitis in southern Pakistan, april 2015-january 2018

Authors

Tazeen Fatima, Aga Khan University
Abida Rais, Aga Khan UniversityFollow
Erum Khan, Aga Khan UniversityFollow
Susan L. Hills, Centers for Disease Control and Prevention, United States of America
Trudy V. Chambers, Centers for Disease Control and Prevention, United States of America
Aneeta Hotwani, Aga Khan UniversityFollow
Shahida Qureshi, Aga Khan UniversityFollow
Saad Shafqat, Aga Khan UniversityFollow
Saima Malik, Aga Khan University
Farah Qamar, Aga Khan UniversityFollow
Fatima Mir, Aga Khan UniversityFollow
Anthony A. Marfin, Center for Vaccine Innovation and Access, United States of America
Anita K. M. Zaidi, Aga Khan UniversityFollow
Asif Raza Khowaja, University of British Columbia, Vancouver, Canada
Sadia Shakoor, Aga Khan UniversityFollow

Document Type

Article

Department

Medicine; Neurology; Paediatrics and Child Health; Pathology and Laboratory Medicine

Abstract

Background: Japanese encephalitis (JE) occurs in fewer than 1% of JE virus (JEV) infections, often with catastrophic sequelae including death and neuropsychiatric disability. JEV transmission in Pakistan was documented in 1980s and 1990s, but recent evidence is lacking. Our objective was to investigate JEV as a cause of acute encephalitis in Pakistan.
Methods: Persons aged ≥1 month with possible JE admitted to two acute care hospitals in Karachi, Pakistan from April 2015 to January 2018 were enrolled. Cerebrospinal fluid (CSF) or serum samples were tested for JEV immunoglobulin M (IgM) using the InBios JE DetectTM assay. Positive or equivocal samples had confirmatory testing using plaque reduction neutralization tests.
Results: Among 227 patients, testing was performed on CSF in 174 (77%) and on serum in 53 (23%) patients. Six of eight patient samples positive or equivocal for JEV IgM had sufficient volume for confirmatory testing. One patient had evidence of recent West Nile virus (WNV) neurologic infection based on CSF testing. One patient each had recent dengue virus (DENV) infection and WNV infection based on serum results. Recent flavivirus infections were identified in two persons, one each based on CSF and serum results. Specific flaviviruses could not be identified due to serologic cross-reactivity. For the sixth person, JEV neutralizing antibodies were confirmed in CSF but there was insufficient volume for further testing.
Conclusions: Hospital-based JE surveillance in Karachi, Pakistan could not confirm or exclude local JEV transmission. Nonetheless, Pakistan remains at risk for JE due to presence of the mosquito vector, amplifying hosts, and rice irrigation. Laboratory surveillance for JE should continue among persons with acute encephalitis. However, in view of serological cross-reactivity, confirmatory testing of JE IgM positive samples at a reference laboratory is essential.

Comments

Pagination are not provided by the author/publisher

Publication (Name of Journal)

PLoS One

Recommended Citation

Fatima, T., Rais, A., Khan, E., Hills, S. L., Chambers, T. V., Hotwani, A., Qureshi, S., Shafqat, S., Malik, S., Qamar, F., Mir, F., Marfin, A. A., Zaidi, A., Khowaja, A. R., Shakoor, S. (2020). Investigation of japanese encephalitis virus as a cause of acute encephalitis in southern Pakistan, april 2015-january 2018. PLoS One, 15(6), e0234584.
Available at: https://ecommons.aku.edu/pakistan_fhs_mc_pathol_microbiol/1249

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