- In what seems to be yet another epidemic outbreak, a number of districts in Bihar are witnessing a surge in the number of Acute Encephalitis Syndrome (AES) cases.
- Districts in North Bihar including Muzaffarpur, Vaishali, Sitamarhi, Samastipur, Sheohar, East and West Champaran are witnessing upsurge in the Acute Encephalitis Syndrome cases.
- According to official estimates, more than 48 cases have been reported since January 2019. However, the number of actual cases are said to much higher.
In focus: Acute Encephalitis Syndrome outbreak in India
- Acute Encephalitis Syndrome is a spectrum of diseases classified based on similar clinical syndromes.
- It is primarily a neurological condition characterized by sudden onset of fever and altered consciousness.
- Symptoms include fever, abdominal pain, repeated vomiting, lethargy, seizures, loss of consciousness and even death.
- Hypoglycemia is a common feature observed in more than 50% of the cases.
- The fatality rate is extremely high. (10-35%)
- Vulnerable group
- Children in the age group 6 months – 15 years.
- Majority of the cases occur in the age group within 10 years.
- This is due to lack of cumulative immunity due to natural infection
- The etiology of disease is still unknown.
- It can be caused by different viruses, bacteria, fungus, parasites, spirochetes, toxins etc.
- It is known to occur between March and June due to high temperature (42 degree C) and more than average humidity which are ideal conditions for the outbreak.
- Depending on the nature of causes it can be divided into 2 groups – JE-causing AES and Non-JE AES.
Japanese Encephalitis Virus causes 11-15% of the acute encephalitis cases.
- About Japanese Encephalitis
- A mosquito borne viral disease.
- It is a zoonotic disease.
- Pigs and birds are the natural hosts.
- It affects humans and horses.
- The virus is transmitted by Culex Mosquitoes. (same in case of West Nile Fever)
- Enterovirus (RNA virus)
- These cases are reported in Gorakhpur in UP and Muzzafarpur in Bihar.
- The enterovirus travels along the course of the River Sarayu (tributary of Gandak) from Gorakhpur to Muzzafarpur.
- A study in 2015 established a relationship between consumption of litchi and AES.
- Exposure to a toxin in litchi (hypoglycin A and methylene cyclopropylglycine (MCPG).
- Scrub typhus
- A bacterial disease has been identified as a leading cause in a number of AES outbreaks in India.
- Other causes
- Fungal disease
- Protozoan disease
Incidence in India
- About 80% of the cases occur in Assam, Bihar, Karnataka, Tamil Nadu and Uttar Pradesh.
- The worst AES outbreaks coincide with the Japanese Encephalitis outbreaks in 1973 (WB), 1978 (UP), Gorakhpur (UP) in 2005.
- North Bihar has witnessed recurrent outbreaks in 2011, 2012, 2014, 2016, 2017 and 2019.
- UP and Bihar has witnessed more than 44000 cases and 6000 deaths between 2008 and 2014 making it a public health challenge in India.
Strategy to arrest AES outbreaks
- India has AES guidelines focusing on
- Since Japanese Encephalitis causes 15% of the AES cases, JE vaccination drive was introduce in 2006 following the 2005-outbreak.
- In 2014 JE vaccine was included under the National immunization programme.
- Improved sanitation
- Improved nutrition
- Water Traps
- Construction of water traps in the course of Sarayu River to prevent spread of pathogens from Gorakhpur in UP to Muzzaffarpur in Bihar.
- Awareness programme
Management of the symptoms
- Administering dextrose to control hypoglycemia.
- Anti-biotics, fever-management etc
- The major challenge is inability to identify a single cayse (aetiology)
- In most of the cases the inability to isolate an infectious aetiological agent is the fundamental challenge to effective prevention and management.
- Lack of research on aetiology, transmission, risk factors and environmental exposures makes the disease surveillance poor.
- Poor levels of sanitation, nutrition, public health facilities etc aggravate the already high Case Fatality Rate of 10-35%.