Epidemiological Profile of Acute Viral Encephalitis

OBJECTIVE

To study the etiology and clinico-epidemiological profile of acute viral encephalitis in children with acute encephalitis syndrome (AES).

METHODS

An observational study including 100 patients fulfilling the criteria for AES was conducted in children of age group 1 mo - 16 y. Viral isolation was done on RD cells, HEp-2 cells and Vero cells from the cerebrospinal fluid samples of suspected viral encephalitis (VE) cases. An enzyme immunoassay for IgM antibodies was performed for measles, mumps, Varicella zoster virus (VZV), Herpes simplex virus 1 (HSV1) and Japanese encephalitis virus (JEV). Multiplex polymerase chain reaction (PCR) was done for Cytomegalovirus, Epstein Barr virus (EBV), HSV1 & 2, VZV, Enterovirus, Parecho virus, Human Herpes virus (HHV 6, 7) and Parvovirus B19. A micro neutralization test was performed for Enterovirus 71.

RESULTS

Out of enrolled 100 patients, 73 were of probable viral encephalitis. HSV1 (31.50%) was the commonest virus followed by Adenovirus (10.95%), Parvovirus (2.73%), JE virus (1.36%), Enterovirus (1.36%), EBV (1.36%), and mixed infection with HSV & EBV (1.36%). HSV 1 caused significant morbidity in children. The common computed tomography (CT) findings were hypodensities in the fronto- parietal lobe followed by cerebral edema.

CONCLUSIONS

The landscape of AES in India has changed in the previous decade, and both outbreak investigations and surveillance studies have increasingly reported non-JEV etiologies; because of these findings there is a need to explore additional strategies to prevent AES beyond vector control and JEV vaccination.

Using network analysis to explore if professional opinions on Japanese encephalitis risk factors in Nepal reflect a socio-ecological system perspective

Japanese encephalitis (JE) is the leading cause of viral encephalitis in Asia and a significant public health problem in Nepal. Its epidemiology is influenced by factors affecting its amplifying hosts (pigs), vectors (mosquitoes), and dead-end hosts (including people). While most control efforts target reduced susceptibility to infection either by vaccination of people or pigs or by reduced exposure to mosquitoes; the economic reality of Nepal makes it challenging to implement standard JE control measures. An ecohealth approach has been nominated as a way to assist in finding and prioritizing locally relevant strategies for JE control that may be viable, feasible, and acceptable. We sought to understand if Nepalese experts responsible for JE management conceived of its epidemiology in terms of a socio-ecological system to determine if they would consider ecohealth approaches. Network analysis suggested that they did not conceive JE risk as a product of a socio-ecological system. Traditional proximal risk factors of pigs, mosquitoes, and vaccination predominated experts' conception of JE risk. People seeking to encourage an ecohealth approach or social change models to JE management in Nepal may benefit from adopting social marketing concepts to encourage and empower local experts to examine JE from a socio-ecological perspective.

Knowledge and practices of pig farmers regarding Japanese encephalitis in Kathmandu, Nepal

Japanese encephalitis (JE) is the single largest cause of viral encephalitis in the world and has been endemic in Nepal since the early 1980s. Since then, it has spread from its origins in lowland plains to the Kathmandu Valley as well as in hill and mountain districts. Pigs are amplifying hosts for the virus. The Nepal government has been encouraging the development of pig farming as a means of poverty alleviation. Whereas other countries have reduced JE through vaccination programmes and improvements in pig husbandry, these options are not economically possible in Nepal. The objective of this study was to examine the occupational risk of pig farmers in Nepal and to determine their level of knowledge and practice of JE prevention techniques. We surveyed 100 randomly selected pig farmers in the Kathmandu District and found that pig farmers were exposed to many JE risk factors including poverty and close proximity to pigs, rice paddy fields and water birds, which are the definitive hosts for the virus. Forty-two percent of the farmers had heard of JE, 20% associated it with mosquito bites and 7% named pigs as risk factors. Few protective measures were taken. None of the farmers were vaccinated against JE nor were any pigs, despite an ongoing human vaccination campaign. This farming community had little ownership of land and limited education. JE education programmes must consider gender differences in access to public health information as there were an equal number of male and female farmers. We provide findings that can inform future JE education programmes for this vulnerable population.