Japanese encephalitis - India (08): (UP, AS)
Date: Sat 29 Aug 2009
Source: The Times of India (TOI), Times News Network (TNN) [edited]
<http://timesofindia.indiatimes.com/news/india/In-Assam-Japanese-Encephalitis-records-an-age-shift/articleshow/4946281.cms>
India has started to record a complete age shift in those infected by
the Japanese encephalitis (JE) [virus] -- the vector borne viral
killer. Till now, scientists believed that in most JE endemic states,
the virus infected only the under-15 age group. However, a present
outbreak in Assam has the Union health ministry perplexed. Almost 74
percent of the cases reported till now in the state have been in the
above-15 age group.
Till now this year [2009], Assam has recorded 164 cases of acute
encephalitis syndrome (AES) -- a severe neurological condition
associated with significant morbidity and mortality. Of these, 91 have
now been lab confirmed to be caused by JE [virus]. AED has also killed
78 people since April [2009].
"Around 67 of these 91 JE cases (74 percent) are above 15 years of
age, with the eldest in this affected group being a 58-year-old. This
is highly unusual and we have no idea why it has happened. This is a
new trend," JE expert from international NGO Path Dr Pritu Dhalaria
told TOI.
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 -- 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 [approx. USD 3.1 million. A crore is a unit in the Indian
numbering system equal to 10 million. - Mod.TY] "The state had just
one query -- will 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," Dr Dhalaria said.
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].
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," officials said.
The JE virus is transmitted to humans via the bite of an infected
mosquito. The mosquitoes usually get infected when feeding on domestic
pigs [or wild birds. - Mod.TY] 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.
[Byline: Kounteya Sinha]
Source: The Times of India (TOI), Times News Network (TNN) [edited]
<http://timesofindia.indiatimes.com/news/india/In-Assam-Japanese-Encephalitis-records-an-age-shift/articleshow/4946281.cms>
India has started to record a complete age shift in those infected by
the Japanese encephalitis (JE) [virus] -- the vector borne viral
killer. Till now, scientists believed that in most JE endemic states,
the virus infected only the under-15 age group. However, a present
outbreak in Assam has the Union health ministry perplexed. Almost 74
percent of the cases reported till now in the state have been in the
above-15 age group.
Till now this year [2009], Assam has recorded 164 cases of acute
encephalitis syndrome (AES) -- a severe neurological condition
associated with significant morbidity and mortality. Of these, 91 have
now been lab confirmed to be caused by JE [virus]. AED has also killed
78 people since April [2009].
"Around 67 of these 91 JE cases (74 percent) are above 15 years of
age, with the eldest in this affected group being a 58-year-old. This
is highly unusual and we have no idea why it has happened. This is a
new trend," JE expert from international NGO Path Dr Pritu Dhalaria
told TOI.
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 -- 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 [approx. USD 3.1 million. A crore is a unit in the Indian
numbering system equal to 10 million. - Mod.TY] "The state had just
one query -- will 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," Dr Dhalaria said.
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].
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," officials said.
The JE virus is transmitted to humans via the bite of an infected
mosquito. The mosquitoes usually get infected when feeding on domestic
pigs [or wild birds. - Mod.TY] 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.
[Byline: Kounteya Sinha]
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