| ETERNAL EPISODE OF JAPANESE ENCEPHALITIS IN INDIA |
Situation
Japanese encephalitis is taking new dimensions in making its endemic footprints in our country especially in northern India. Uttar Pradesh, being the main candidate had been recorded with maximum number of cases, this year also with some unusual epidemic highlights. The demography of this region is conducive for the spread of JE due to plenty of rice fields and a bowl- shaped landscape that allows water to collect in pools. The Japanese encephalitis virus has a complex life cycle involving domestic pigs and a specific type of mosquito, Culex tritaeniorhynchus (and other closely related Culex species) that lives in such rice-growing and pig-farming regions. |
Pathology
The JE virus is transmitted to humans via the bite of an infected mosquito. The mosquitoes usually get infected when feeding on domestic pigs that already carry the virus. The Culex tritaeniorhynchus group of mosquitoes is the primary transmitter of JE virus to humans.
If a mosquito bites an infected animal and then bites a human, the person can become infected with the JE virus. After a person is bitten, the JE virus invades the central nervous system, damaging the brain and spinal cord. Immunization is the most effective approach to prevent the disease.
Highlight of the epidemic
The nation has started to record even a complete age shift in those infected by the disease. Age of patients suffering from this disease ranged mostly from 3 months to 15 years and the male to female ratio was normally 1.4 to 1. However, a present outbreak in Assam has made the Union health ministry perplexed. Almost 74% of the cases reported till now in the state have been in the above-15 age group, with the eldest in this affected group being a 58-year-old. |
Carrying vehicle of JE virus
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Vaccine coverage
India has so far failed to develop an effective vaccination programme. Vaccine coverage with the imported vaccines from china had not been satisfactory this year. Though the epidemiology of this disease is complex, necessity is there to investigate the new facet of this endemic JE and this article depicts in this way not only the impacts behind but also signalizes the measures to be taken at this instant.
Till now, India vaccinated only the under-15 age group with the JE vaccine. However, this age shift trend has now made the Assam government decide to vaccinate the entire population in the 7 worst affected districts viz., Sibsagar, Dibrugarh, Tinsukia, Jorhat, Kolaghat, Dimaji, and Lakhimpur.
The government has estimated that 8 million doses of the vaccine will be required to vaccinate the entire population in these districts. The vaccine and operational hurdles will in total cost the state INR 15 crore. There is a major query that whether the vaccine be safe for adults, and it is. The vaccine will have to be given in the same dose as for kids and is as effective on adults. Nepal used the same strategy in 4 of its worst affected districts in 2007.
The vaccine will have to be imported from China, which Path is facilitating. It will, however, take 6 months for the vaccines to arrive. India has been completely dependent on China for its supply of the SA14-14-2 anti-JE (virus) vaccine from China National Biotech Group's Chengdu Institute. India first imported the Chinese vaccine in February 2006 after a sudden outbreak of JE the previous year killed over 1800 people.
The single shot vaccine made from a live attenuated virus (live cells like bacteria grown in laboratory, infected with the JE virus and then
purified to make the vaccine) has 90 percent efficacy and costs around INR 10 per dose [USD 0.21]. |
Children being admitted to hospitals in Uttar Pradesh State |
Reasons for age-shift:
According to vector experts at NICD [National Institute of Communicable Diseases], the age shift in Assam could have happened because the adults didn't have immunity against the virus. In known endemic belts of Karnataka, Tamil Nadu, Andhra Pradesh, and Uttar Pradesh, transmission usually occurred in children because adults have some immunity against it due to repeated exposure. Maybe the virus is spreading to new uninfected areas of Assam where lack of an earlier outbreak has made even adults vulnerable, as per the persuasions of officials.
Swine flu influence
By mid of August, more than 200 cases and 40 deaths have taken place in eastern UP due to encephalitis, the disease which had a mortality rate between 30 to 40 percent. By the same time, only 20 cases of mild flu have been reported. 8-10 patients are being admitted daily at BDR Medical College. However, while all government attention is focused on swine flu [influenza (H1N1) 2009], few seem to be bothered about encephalitis. For swine flu, all hospitals have been put on alert, whereas there is no such alert for encephalitis. Tests for detection of swine flu, each of which is 3 times costlier, are being done daily, while encephalitis-detection tests are being conducted at a maximum of thrice a week.
North-eastern footprints:
Most of the cases reported till now are from various areas in Dimapur including Purana Bazar, Thlixu village, Diphupar, Notun Basti, Supply Colony and Ao Kashiram. One isolated case from Tenning under Peren district and around 2 from Tuli have been reported so far. |
Favouring habitats
Japanese Encephalitis (JE) has posed a serious threat in Nagaland, particularly with unmonitored rearing of pigs in residential areas. And with the late onset of monsoon this year, it would only mean more density of mosquitoes and so chances of more cases of JE disease. Even in developed towns like Dimapur, pigsties can be found in backyards of many homes, in close proximity to living quarters of people. The enforcement of laws like “ the pigs should normally be reared 5 kilometers away from human inhabitation, is practically impossible in Nagaland. Added to that, the town and municipal councils are yet to wake up from their slumber, to monitor rearing of pigs in residential areas.
Officially, 34 people have died of encephalitis in Upper Assam in July [2009], according to newspaper reports, while the unofficial number has been pegged beyond 50. More than 100 people are now battling the disease in hospitals across Upper Assam. |
Children surviving around breeding grounds
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Control measures
Assam
Efforts are being made to identify the outbreak areas of the disease so that fogging and impregnation of bed-nets would be carried out along with sensitization.
Nagaland
Though, National Vector Borne Disease Control Programme, Nagaland under malaria department has been making efforts to take preventive measures, awareness of the viral disease is found to be still lacking among the citizens, with many confusing it for malaria or typhoid.
Uttar Pradesh
These JE reports indicate the need for a well organized and integrated prevention, control and treatment approach to JE in areas where the virus is endemic. Sentinel pig and Culex mosquito monitoring would provide an indication of the time and places where transmission is becoming active. This requires rapid laboratory support. Ongoing public education reduce mosquito breeding and avoid mosquito bites would reduce human cases. Public education is also important for timely visits to health centers and hospitals to improve early provision of treatment of JE virus infected patients and reduce case fatality rates.
India has an active JE virus vaccination program, and it would be of interest to know its extent in Nagaland and Upper Assam. All of these measures require considerable financial support, and would compete with other important public health programs.
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