Download Japanese Encephalitis in Nepal, Shiflet

Jennifer Shiflet
Japanese Encephalitis in Nepal
From: Secretary of Health, Nepal
To: Minister of Finance, Nepal
Introduction:
Nepal has the second highest prevalence of Japanese encephalitis (JE) in South East
Asia1. One in five cases of JE results in death and those who survive frequently suffer from
residual neuropsychiatric disorders2. Most cases occur in children ages 5-15 years living in rural
plain areas of the western, mid-western, and far-western regions of Nepal that border India1. JE
has recently been confirmed in 54 of the 75 districts in Nepal2. Those not using insecticide
treated bed nets (ITNs), living amongst animal reservoirs of the disease and practicing poor
agricultural practices in JE-endemic areas are most at risk3. Most JE cases are asymptomatic and
therefore undetected4. No effective drug treatment for JE exists and few are aware of the JE
vaccine2. JE contributes to high levels of malnutrition, lack of education, and poverty3.
Integration of JE immunization on National Immunization Days and increased ITN use are the
most effective means to decrease JE incidence rates4. Despite efforts from Government and nongovernment organizations, JE constitutes a major cause of morbidity and mortality in our country
and remains a priority for public health intervention.
Nature and Magnitude of the Problem:
Japanese encephalitis has manifested as a major burden for our people in the last three
decades. Between 1978 and 2003, 26,667 cases and 5,381 deaths have been reported with case
fatality rates ranging from 9.8 percent to 46.3 percent during that time4. Since 2005, 1,802 cases
and 283 deaths have been reported, yielding a case fatality rate of 16 percent1. Of those who
survive, about 30 percent develop some form of permanent neurological debility6. Only about 10
percent will recover to their pre-infective health status6.
One in five JE cases will rapidly progress to severe encephalitis and progressive coma2.
Acute encephalitis syndrome (AES) manifests as an acute onset of fever and a change in mental
status (e.g., confusion, disorientation, coma, or inability to talk) or an onset of seizures5.
Surveillance of JE is mainly documented based on the number of AES cases that are laboratoryconfirmed within the first 4-7 days after infection2. However, JE has an incubation period of 414 days and rarely causes clinical symptoms2. More accurate surveillance of JE must be
ensured, as only 1 case is reported for every 300 asymptomatic cases6.
JE immunization and use of ITNs are the most effective known control measures. Only
about 32 percent of Nepalese people are aware of JE7. In households surveyed for JE, 52 percent
had at least one family member not protected by an ITN7. Only 14 percent of those aware of JE
are aware of the JE vaccination7. Increased socioeconomic status is associated with knowledge
and awareness of JE and reduced risk behavior7.
Affected Populations:
Children that are male and under the age of 15, living in rural areas, are most affected by
Japanese encephalitis. About half of all JE cases are reported in children under the age of 15 and
the incidence rate is the highest amongst children age 5-15 years6. Of those infected, about 60
percent are male6. The most fatalities and residual neurological and psychiatric disorders are
seen in children under the age of 102.
1
JE is seasonally endemic in the Terai region and in villages along the river banks between
hills . Recently, JE has also been reported and is now endemic in the Kathmandu valley in the
hill region5. From 2004 through 2006, laboratory-confirmed JE cases have also been reported in
the hill and mountain regions where JE was previously not suspected to be endemic5.
3,5
Risk Factors:
Our entire population is at risk for JE, but those most at risk are uneducated people living
in rural parts of endemic areas without access to ITNs and JE vaccines. A higher level of
educational attainment directly relates to better awareness of JE and influences bed net use7. The
use of ITNs directly reduces the risk of JE transmission and serves as an effective preventative
measure7. Incorrect or lack of use of ITNs leaves our people at high risk for infection4. Those
living on pig farms are also more at risk because pigs serve as reservoirs for JE3. Risk is also
increased during exposure to areas with mosquito breeding grounds after the monsoon season,
between the months of July to September6. Poor agricultural practices increase the amount of
available breeding grounds for the mosquito vectors and therefore also contribute to increased
risk6.
Social and Economic Consequences:
Japanese encephalitis contributes to malnutrition, lack of education, and poverty.
Children infected with JE often suffer from gastrointestinal dysfunction that leads to
malnourishment2. Malnutrition from JE and other infectious diseases is associated with high
rates of child stunting3. JE contributes to our high under-five mortality rate of 91 deaths per
1,000 live births3. Residual neuropsychiatric disabilities from JE infection restrict learning
ability and school performance, contributing to our country’s 52 percent literacy rate3. Such
disabilities also inhibit physical performance and can lead to unemployment for those living in
regions economically dependent on agriculture6. A poor workforce offers little attraction for
potential economic investment in JE-endemic areas. JE not only affects our poor, but it also
perpetuates more poverty by restricting our citizens’ opportunities to increase socioeconomic
status.
Priority Action Steps:
In order to control the outbreaks of JE, awareness of the disease must be spread and
vector control measures, surveillance practices, and immunization efforts must be intensified1.
Community participation should be encouraged to educate citizens about the transmission and
prevention of JE3. Community education campaigns are critical to decreasing risk behaviors and
improving preventative behaviors for JE7. Educating people about the use of ITNs and
distribution of more ITNs to affected areas helps to decrease the number of humans bitten by
mosquitoes carrying the virus from infected animal reservoirs3. Training of health workers on
case recognition and intervention strategies must be implemented to enhance JE surveillance7.
Improving agricultural practices to prevent flooding of rice fields where mosquito vectors breed
will also contribute to decreased levels of JE infection2.
Mass immunization campaigns in known JE-endemic areas will most effectively assuage
the incidence and mortality of JE5. Large-scale JE vaccination has already been proven effective
in significantly decreasing the incidence of JE in regions of China, Japan, and Thailand2. Of the
three types of JE vaccines that exist, two are commercially available internationally and are safe
to administer to children2. The costs of the vaccines are relatively low and only two doses at 1-2
2
week intervals are required for immunity2. More government funding must be directed towards
the purchase and distribution of JE vaccines if there is any hope to extinguish JE from our
country.
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References:
“Immunization and Vaccine Development: Japanese Encephalitis.” World Health
Organization. 3 December 2010. http://www.searo.who.int/EN/Section1226/Section2073.asp
1
“Japanese Encephalitis Vaccines: WHO Position Paper.” Weekly Epidemiological Record. 6
December 2010. http://www.who.int/docstore/wer/pdf/1998/wer7344.pdf
2
3
Shiba, K., Kazuko, H., Ayako, A. & Yoshimi, O. (2002). Infectious diseases and malnutrition
status in Nepal: An overview. Journal of Malnutrition 8(2). 191-200.
http://nutriweb.org.my/publications/mjn008_2/mjn8n2_art6.pdf
“Country Health System Profile: Nepal.” World Health Organization. 3 December 2010.
http://www.searo.who.int/EN/Section313/Section1523_6867.htm
4
“Japanese Encephalitis in Hill and Mountain Districts, Nepal.” Centers for Disease Control. 6
December 2010. http://www.cdc.gov/EID/content/15/10/1691.htm
5
“Epidemiology of Japanese Encephalitis in Nepal.” World Health Organization. 3 December
2010. http://www.nepjol.info/index.php/JNPS/article/download/1600/1533
6
“The Nepal Survey on Malaria, Japanese Encephalitis and Kala-azar.” USAID. 6 December
2010. http://pdf.usaid.gov/pdf_docs/PNADB076.pdf
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