New Delhi, Aug. 18: Poor surveillance, incomplete diagnosis and unsubstantiated scientific claims have stymied India’s efforts to control the mystery encephalitis that has killed 3,000 children in eastern India over the past three years, health researchers have said.
A new study has warned that low-quality surveillance appears to be obstructing attempts to understand the cause of the acute encephalitis syndrome (AES) observed mainly in Assam, Bengal, Bihar and Uttar Pradesh with sporadic cases in other states.
The Union health ministry documented more than 21,600 patients with AES, including 3,171 deaths, most of them in the eastern states, between 2010 and 2012. A central government programme that tracks encephalitis, or brain inflammation, has claimed that waterborne enteroviruses have replaced the Japanese encephalitis virus as the main cause of encephalitis. But many scientists believe the identity of the viruses still remains hazy.
“In this time and age, there can be no excuse for failing to identify an unknown virus,” said a senior government scientist who requested not to be named. “Technology exists today to sequence a virus in less than six hours,” the scientist told The Telegraph.
The study on the quality of surveillance and diagnosis examined the case records of patients from Kushinagar district in Uttar Pradesh and suggested that assertions that waterborne enteroviruses are the dominant cause of encephalitis are not backed by adequate scientific evidence.
“Without reliable scientific evidence, it is very easy to shift the hypothesis (of the cause of the encephalitis),” said Manish Kakkar, a microbiologist and faculty member at the Public Health Foundation of India, New Delhi, a research and training institution.
Kushinagar has been among hubs of encephalitis in eastern India where the Japanese encephalitis virus picked up through mosquito bites had been considered the primary cause of encephalitis from the 1970s until about 2010.
The Union health ministry had introduced a mass vaccination campaign against the Japanese encephalitis virus in the affected states in eastern India in 2006 with a fresh campaign in 2010, but both Japanese encephalitis and AES have persisted.
Health ministry figures suggest that AES has outnumbered Japanese encephalitis (JE) over the past three years. During 2012, for instance, India had 745 cases of JE and 8,344 cases of AES, with 140 deaths from JE and 1,256 deaths from AES.
Kakkar and his colleagues have found that the results of diagnostic tests on samples or blood or cerebrospinal fluid from 590 (82 per cent) out of 721 encephalitis patients registered at a district hospital during 2011 were still awaited in July 2012 — after virtually all the children had been discharged or died. In 80 per cent of the cases, health authorities had no idea whether patients had been vaccinated.
“These findings are shocking — with such gaps in information, it’s hard to estimate the effect of the vaccination or to determine what might be causing the illness,” said Kakkar, lead author of the study published in the journal Emerging Infectious Diseases.
The National Institute of Virology (NIV), Pune, under the Indian Council of Medical Research has set up a surveillance centre in eastern Uttar Pradesh to help analyse samples from patients and try to identify the cause of the AES.
The NIV has said it has detected in samples of cerebrospinal fluid of patients with encephalitis genetic material resembling that of enterovirus 89 and enterovirus 76 and throat swabs of patients have turned up signatures of the coxsackie virus and two types of echovirus. “Enteroviruses are known to cause encephalitis and our evidence is strong,” a senior NIV scientist said.
But Kakkar and his colleagues say the focus of health authorities has shifted to enteroviruses even though the studies that found enteroviruses in patient samples have not demonstrated that waterborne pathogens are the main cause of the encephalitis.
“What Kushinagar shows is India’s failure to establish a reliable public health surveillance network,” said T. Jacob John, a senior virologist formerly with the Christian Medical College, Vellore.
“We don’t need pinpoint the cause to treat children with encephalitis, for the medical management of the illness,” John said. “But to prevent new infections, we have to understand what’s causing them.”