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Japanese
Encephalitis is a viral zoonotic disease of Public health
importance, because of its epidemic potential and high case mortality rate.
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It
is a mosquito borne zoonotic disease.
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The
virus infects mainly animals through migrating birds. Pig is
the amplifier host. Man is affected incidentally.
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J.E.
is primarily a disease of rural agricultural areas where vector
mosquitoes proliferate in close association with pigs and other
animal reservoirs.
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Its
epidemic have also been reported in peri-urban areas where similar
conditions are also exist Tamilnadu.
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Man
to man transmission is not possible.
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The
detection of cases are difficult due to the disease apparent and in
apparent nature.
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Once
the human is infected with the disease it leads to death in most of
the cases.
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If
survive the patient will be with severed physical and neurological complications.
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In
Tamil Nadu cases are recorded for the last 20 years and the cases
have occurred in a sporadic manner in certain areas.
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The
outbreaks have been limited to 2-3 months duration in a year.
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The
disease is recorded predominantly from rural areas and even there
usually not more than one case is seen per village.
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In
the early 80s cases were reported from Tamilnadu in the following
revenue districts Tiruvannamalai, Dharmapuri, Namakkal,
Trichirapalli, Dindigul, Theni, Madurai,Virdhunagar,
Tirinelveli, and Tuticorin.
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However
for the past 5 years sporadic cases are reported from Villupuram,
Cuddalore,and Perambalur districts only.
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The
incidence during the last 5 years is given below.
INCIDENT IN THE STATE
CONTROL
AND PREVENTIVE MEASURES:
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Vaccination
against J.E. is being carried out in a regular basis in Tamil Nadu
for the past three years.
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Children
1-12 years of age in the selected villages in the district of
Perambalur are covered.
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The
criteria for selection of these areas is based on death of children
due to Japanese Encephalitis occurring every year during the past 3
years. Once a village has been selected for
immunisation children 1-14 years are administered primary
vaccination with 3 doses before 2 years of age and 3 booster doses at
the age of 4, 8 and 11th years of the child.
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The
coverage with Japanese Encephalitis vaccination varied from
82-94%. So far 2,92,327 children were immunized against
Japanese encephalitis vaccination. The total amount spent
towards the purchase of J.E. vaccines are given below in lakhs.
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Anticipatory
spray during premonsoon has been carried out covering affected
villages where J.E. cases were recorded during the last 3 years.
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In
the J.E. endemic districts villages where deaths due to J.E. during
any of the last 3 years have been recorded the anticipatory fogging
followed by residual spray covering animal shelters as well as human
dwellings are being carried out. The amount spent towards the
payment of wages for spray field workers is furnished hereunder.
DIAGNOSTIC
FACILITIES:
Sera
are collected from the J.E. cases and sent to Virology department,
Madurai Medical college (or) King Institute, Guindy, Chennai (or)
Institute of Vector Control and Zoonoses, Hosur for Laboratory
diagnosis of J.E. case.
Vector
mosquitoes collected from the field are sent to CRME, Madurai and
Institute of Vector control and Zoonoses, Hosur for PCR analysis for
detection of virus.
RESEARCH
PROJECT:
In
collaboration with the public health department, the CRME, Madurai
is undertaking the impregnated curtains trials at Sirimangalam and
Nallur Primary Health Centres in Cuddalaore district for control of
J.E. vectors.
PROBLEM
/ CONSTRAINTS:
1.
This disease is related to the agriculture practice of Paddy which
needs water for cultivation. The water collection in the paddy
fields are the profuse breeding source for J.E.vectors. Thus
the vector control becomes very difficult. Antilarval is not possible.
2.
As a source reduction measure, weekly dry day in the paddy fileds
through the Agriculture department is suggested for the control of
larval breeding.
3.
Pig rearing provide a livelihood for rural poor . Pigs are the
Amplifier host in the J.E. disease. Isolation of pigs and
formation of Pig shyes outside the village limits are practically
difficult. Thus it is posing a socio-economic problem.
4.
Periodical migration of birds which establishes local foci in the
area which cannot be controlled.
Despite
the above constraints and problems faced and due to various control
and preventive measures undertaken by the State Public Health
Department the incidence is under control and no case is recorded
during this year in the state. Preventive measures are continued as
cases are being recorded in neighboring states.
