Myanmar Health Sciences Research Journal
Original Articles :
Myanamr Health Research Registration 2020; 32(2): 95-104.
DOI: https://doi.org/10.34299/mhsrj.00988

Improving Awareness and Transmission Risk Reduction Related to Japanese Encephalitis in Endemic Region of Myanmar

Maung Maung Mya, Aung Ye Naung Win, Sein Thaung, Zar Ni Min Hein, Pwint Mon Oo, Zaw Lin, Tin Oo, Khin Thet Wai & Kyaw Zin Thant

Myanmar Health Sciences Research Journal, 2020; 32(2):95-104

ABSTRACT

Japanese encephalitic (JE) is one of the public health problems in Myanmar. It is a zoonotic disease caused by JE virus spreading to human through the bite of Culex mosquitoes. Improving awareness and transmission risk reduction related to Japanese encephalitis study was conducted from October 2017 to March 2018 in Kyow Pin Sakan and Chaung Khawa villages in Hmaw Inn RHC, and Ye Kyi and Yun Thwe villages in Taw Kalut RHC, Letpadan Township, Bago Region where JE cases were reported. For entomological surveys, breeding sites and vector density were sought in all four selected villages. The sociodemo- graphic characteristics, KAP of the study population were described using percentage. The result revealed that main JE vector Culex tritaeniorhynchus adults were found to be highest in Ye Kyi village (59%) followed by Yun Thwe village (44.68%) and its larvae were abundantly collected in all selected villages in water pools and rice fields water. Highest number of Cx. vishnui (33.53%) was found in Chaung Khawa village. A total of 204 households were recruited and 85.5% lived in bamboo and wooden house. About 80% of households had unsatisfactory water drainage. Only 64.8% of respondents heard about JE by health staff. Highly susceptible age was 5-15 years. For the JE prevention, they reported that sleeping in mosquito nets (54%) and vaccination to human (56.8%), transmission of JE occurred from the bite of infected mosquitoes at night time (51.1%) and they bred in polluted water (61.6%). Attitude of one-third of respondents was satisfactory for all items asked. Practices were relatively good. Therefore, the study recommended that VBDC needs to give LLIN nets and health education to all family members as well as community participation in villages are encouraged to prevent JE transmission through mosquito control
in villages.


RESULT
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Result revealed that the number of main JE vector, Culextritaeniorhynchusadults was found to behighest 236(37.94%) in Ye Kyi village followed by 189(30.38%) in Yun Thwe villages and lowest 21(3.38%fgb) in Kyout Pin Sakan village. The number of secondary JE vector of Cx. vishnui was found to be 172(42.89%) in ChaungKhawavillage followed by 105(26.19%) in Kyout Pin Sakan village and lowest 46(11.47%)was observed in Ye Kyi village (Table 1).

 

Table 1.Prevalence of JE vector and secondary  vectors in selected areas of Letpadan Township, Bago Region

Species

Letpadan Township, Bago Region

Hmaw Inn RHC

Taw Kalut RHC

Total

n(%)

Kyout Pin Sakan

n(%)

ChaungKhawa

n(%)

Ye
Kyi

n(%)

Yun
Thwe

n(%)

Cx.tritaen
iorhynchus*

21

(3.38)

176

(28.30)

236

(37.94)

189

(30.38)

622

(100)

Cx. vishnui**

105

(26.19)

172

(42.89)

46

(11.47)

78

(19.45)

401

(100)

Total

126

(12.32)

348

(34.10)

282

(27.57)

267

(26.10)

1023

(100)

*Primary vector, **Secondary vector

 

Table 2. Prevalence of other mosquito species in selected areas of Letpadan Township,Bago Region

Species

Letpadan Township, Bago Region

Hmaw Inn RHC

Taw Kalut RHC

Kyout
Pin Sakan

n(%)

ChaungKhawa

n(%)

Ye
Kyi

n(%)

Yun Thwe

n(%)

Mansonia

21
(9.09)

26
(15.76)

14
(11.86)

72
(46.15)

Cx. quinquefasciatus

39
(16.88)

6
(3.64)

2
(1.69)

0
(0.00)

Cx .gelidus

0
(0.00)

24
(14.55)

0
(0.00)

15
(9.62)

Cx. fuscocephala

0
(0.00)

28
(16.97)

0
(0.00)

0
(0.00)

An. barbirostris

51
(22.08)

24
(14.55)

24
(20.34)

18
(11.54)

Armigeris

96
(41.56)

35
(21.21)

0
(0.00)

9
(5.77)

An. vagus

12
(5.19)

6
(3.64)

72
(61.02)

42
(26.92)

An. culicifacies

12
(5.19)

0
(0.00)

6
(5.08)

0
(0.00)

An. tessellatus

0
(0.00)

16
(9.70)

0
(0.00)

0
(0.00)

Total

231
(100)

513
(100)

400
(100)

423
(100)

Table 2 shows that percentage ranges of collected species were Cx. quinquefasciatus0.00-16.88%, Cx. gelidus0.00-14.55%, Cx. fuscocepla0.00-16.97%,Mansonia 9.09-46.15% and Anophelesspeciesas
An. vagus3.64-61.02%,An. culicifacies0.00-5.19%, An.tessellatus0.00-9.70%, and An.Barbirostris 11.54-22.08%.

Table 3.Breeding sites and collection of primary and secondary vectors of JE in 4 villages in Letpadan    Township, Bago Region

Type of water    holding place

Kyout Pin Sakan

ChaungKhawa

Ye
Kyi

Yun Thwe

Total No.
of lar-vae

Den-
sity

%

No. of larvae

Tri

Vis

Tri

Vis

Tri

Vis

Tri

Vis

Brick kilns

0

0

0

0

4

3

0

0

7

1.25

Ponds

5

3

2

3

2

2

3

1

21

3.74

Paddy

fields

38

15

21

18

23

12

32

28

187

33.33

Stream

0

0

5

5

6

6

7

3

32

5.71

Creeks

0

0

5

3

3

3

2

1

17

3.03

Irrigation

ditches

7

5

4

3

9

6

8

6

48

8.56

Hyacinth

vegetation

3

2

8

6

5

7

8

6

45

8.02

Water pools

18

9

32

21

28

23

38

35

204

36.36

Total larvae

71

34

77

59

80

62

98

80

561

100

Table 3 shows that highest number of larvae (Cx. tritaeniorhynchus n=98 and Cx. vishnui n=80) were collected in Yun Thwe followed by Ye Kyi (Cx. tritaeniorhynchus n=80 and Cx. vishnui n=62) and lowest was observed in Kyout Pin Sakan (Cx. tritaeniorhynchus n=71 and Cx. vishnui n=34). When com-pared between breeding sources, highest number of primary and secondary JE vector mosquito larvae were collected from polluted water pools (n=204) followed by paddy fields (n=187) and lowest was collected in brick kilns (n=7). Culextritaeniorhynchus and Cx. vishnuilarvae were observed in all type of water holding places except water storage containers. An. barbirostris and An. vagus larvae were collected from ponds, paddy fields, stream and creeks of the Irrawaddy River, marshes around irrigation ditches, hyacinth vegetation and non-polluted water pools.

Table 4 shows that insecticide susceptibility status of JE vector Culextritaeniorhynchus and secondary vector Cx. vishnui collected from four villages were found to be susceptible to WHO recommended insecticides.

Table 4.    Insecticide susceptibility status of JE vector and secondary vector collected from four villages

Village

Species

No.
of mos-que-toes/

test

Tested insec-
ticides (WHO insecticide impregnatedpapers) %

Re-marks

Kyout
Pin Sakan

Culextritaenior- hynchus

Cx. vishnui

7

 

25

Deltamethrin 0.05, Permethrin 0.75

Cyfluthrin  0.15

Susce-ptible

ChaungKhawa

Culextritaenior-hynchus

Cx. vishnui

25

 

25

Deltamethrin 0.05, Permethrin 0.75 Cyfluthrin   0.15

Susce-ptible

Ye Kyi

Culextritaenior-

hynchus

Cx. vishnui

25

 

25

Deltamethrin 0.05, Permethrin 0.75 Cyfluthrin  0.15

Susce-ptible

Yun Thwe

Culextritaenior-

hynchus

Cx. vishnui

25

 

25

Deltamethrin 0.05, Permethrin 0.75

Cyfluthrin  0.15

Susce-ptible

The highest number of Cx. tritaeniorhynchus and Cx. vishnuibiteon cattle (61±3.21 and 95±4.51) bite/cattle/night were followed by pig (56±4.04 and 45±2.00) bite/pig/night and lowest was observed (16±1.15 and 21±1) bite/man/night on human respectability.According to biting behavior of both mosquitoes,Cx.tritaeniorhynchus and Cx.vishnuilike to bite more on cattle and pig than human. The biting rates of Cx. tritaeniorhynchus and Cx. Vishnui were found to be 3.81 and 4.52 fold higher on cattle and 3.5 fold and 2.1 fold higher on pig than on human. Biting rates of both Cx. tritaeniorhynchus and Cx. vishnuiwere observed 2.67 bites/hour and 3.5 bite/hour on human, 10.17 bite/hour and 15.83 bite/hour on cattle and 9.33bite/hour and 7.5 bite/hour on pig, respectively. Cx. tritaeniorhynchus and Cx. vishnuiwere observed as anthrophophilic mosquitoes.

Table 5 shows that morning resting collection was found to be higher in indoor resting (103±7.78) than in outdoor resting density (27±2.12) i.e. 3.82:1 ratio.According to resting behavior, both Culex mosquitoes were endophagic and morning resting behavior revealed that bothmosquitoes were found more endophagic and endophilic than exophagic and exophilic. Indoor resting density was observed as 103 mosquitoes/house or 0.61mosquito/man/hour and out-door resting density was found to be 27mosquitoes/house or 0.16 mosquito/man/hour.

Table 5. Indoor and outdoor resting behavior ofCx.tritaeniorhynchus and Cx. vishnui

Population
in 5house-holds
(n)

Species

Mean
indoor
 resting
mos-
quito/
house
(n)

Mos-
quito
bite/

man/
hour
(n)

Mean
outdoor
resting
mos-
quito/
house
(n)

Mos-
quito
bite/
man/
hour
(n)

14

Cx.
tritaenior-
hynchus

46±3.51

0.27

15±1

0.09

14

Cx. vishnui

57±2.65

0.34

12±1.00

0.07

14

Total
mosquitoes

103±7.78

0.61

27±2.12

0.16

 

IEC source materials that community members got JE information Some 83(47.2%) of this community menbers got JE information from health education session, 70(39.8%) from school-based health education and 23(13.1%) from health talk at RHC/sub-centers.

Of total 204 household members inter-viewed, 176 members answered all questions in this study, comprising 62(35.2%) male and 114(64.8%) female. Concerning their education level, 87(49.4%) were at primary schoollevel 52(29.5%) were middle school, 19(10.8%) were high school, 6(3.4%) were graduates and 12(6.8%) were illiterates.The primary source of hearing the news of JE was television 72(40.9%), radio 38(21.6%), poster 10(5.7%) and health staff 114(64.8%).

For the transmission of JE, the community members answered that the transmission occurred from the pigs 102(58%), water birds 10(5.7%) and cows 10(5.7%),The most susceptible hosts for the transmission of JE were under five years old children (101, 57.4%), 5-15 years old children (101, 57.4%) and pig farmers (31, 17.6%).For the transmission of JE, household members mentioned that it was from the bite of infected mosquitoes at night time (90, 51.1%), day time (48, 27.3%), close contact with pigs (51, 29%).Knowledge about breeding site of Culex mosquito was high; 61.6% said breeding site was polluted water pools and some said the clear water.For the symptoms of JE, 74 members 42% said severe headache 69(39.2%) high fever 55(31.3%) fits and 43(24.4%) loss of consciousness.

For the JE prevention, 145(82.4%) members answered and found different prevention methods, as 95 members (54%) answered sleeping in mosquito nets, 68(38.6%) burning mosquito coil, 43(24.4%) using insecticide spray and 100(56.8%) vaccination to human, respectively, were observed. For the removal of JE vectors, 106 respondents (60.2%)answered spray or fumigation, 23(13.1%) removal of garbage dump and 89(50.6%) larvicides.

 

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INTRODUCTION
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Japanese encephalitis (JE) is a zoonotic disease caused by JE virus (JEV) which is a mosquito-borne flavivirusspreading to human through the bite of Culex mosquitoes. Culextritaeniorhynchusis the primary vector. The virus cycles among amplifier hosts such as pigs, wading birds and human.1Most of JE virus infection in human is asymptomatic and less than 1% of infected people develop symptoms and the incubation period is 5-15 days. Case fatality rate is approximately 20-30% and among survivors, 30-50% has serious neurologic or psychiatric sequanlae.2To date, threats of JE outbreaks are mostly found in 27 countries in Asia and the Pacific Regions including Myanmar. In 1974, Myanmarreported itsfirst outbreak of JE and in 2014, there was an outbreak in 46 villages of nine townships of Rakhine State coupled with lack of awareness of JE transmission and prevention among the villagers.3, 4 As JE is endemic in many parts of Myanmar, the existence of source, vectors and seed virus outbreak can occur at any time. Cases reported were slightly higher in rural population than in urban population. Simultaneously, VBDC implements awareness raising activities to improve alertness but there are limitations. Department of Public Health indicated a total of 491 JE cases occurred in the whole country especially in Yangon, Bago, Taninthayi and Ayeyarwady Regions and Kayin, Rakhine and Shan States.5

In Dawbon Township, Yangon Region JE virus infection was detected in 52.1% of pigs. The known JEV vector mosquito species, especially Culextritaeniorhynchus, were found in the study area but no concurrent human JEV infections were elicited.6 In Myanmar, isolates of virus from pigs in Dike U pig farm were identified as genotype III by PCR7 and isolates from pig blood sample from Thakayta Township were found to be Genotype 1 by DNA sequencer.8

An investigation on JEV infection in Bogalay Township was done in 1999. Findings showed that JEV antibodies were detected in 33% of the pigs. They also found the Culex vector mosquitoes especially Culexvishnui and Culextritaeniorhynchus. JE virus antibodies were not detected among the villagers during the study.9There were 116 deaths reported in Odisha's backward Malkangiri district of India in 2016.
The most important vector is Culextritaeniorhynchus, which feeds on cattle in preference to humans and avariety of mosquito species such as Culextritaeniorhynchus, Culexvishnui and Culex pseudovishnui are the chief vectors of JE in different parts of India.10

Out of four major strategies for JE prevention and control (health education, vector control, immunization of people and pigs and epidemic preparedness and response) guided by World Health Organization, Southeast Asia Regional Office (WHO/SEARO), Myanmar is going to add JE vaccination in national immunezation program for children starting from September 2017. However, community has poor understanding about the interplay of human health, animal health, changing agricultural practices, environment and socio-economic factors, and health care infrastructure. There is a need to focus disease prevention by mitigating the transmission risk through improvement of the awareness raising programs and risk reduction actions by incorporating health concept in rural areas of vulnerable sites in Myanmar. Therefore, the study planned to determine the vector bionomics of Culex species, responsible for Japanese encephalitis transmission and knowledge of JE in household members in 4 villages of Letpadan Township, Bago Region.

 


SUPPLEMENTARY MATERIAL
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Study design

A cross-sectional descriptive study design was used.

Study population

Mosquitoes, pig farmers, household members of villages, village authority persons and health staff from rural health centers were included in the study.

Study area and study period

Four villages of Letpadan Township, Bago Region were selected. The selection is based on the 2012-2016 data of JE cases reported. The study was done from October 2017 to March 2018.

Sample size determination and sampling procedure

Assuming that the prevalence of community awareness of JE in each township being 10% with 6% precision at 95% CI, the sample size was 97 » 102 per township considering for 5% non-response rate. A multistage sampling procedure was used. Total 2 RHCs were selected. Two villages were selected from each RHC, one village that reported JE cases was selected purposively and one was by random selection. From each village,
51 persons who keep pigs in their house compounds (pig farmers) were randomly recruited. Therefore, this study covered two RHC areas, four villages and 204 pig farmers. Purposive sampling was done to recruit the villagers for one focus group discussion (FGD) per village amounting to four FGDs. For each FGD, 7-10 participants were selected. For key informant interviews (KII), one BHS, one health volunteer and one village authority were selected per village, totaling 12 respondents. For entomological surveys, breeding sites and vector density were sought in all selected villages.

The occurrence of JE vectors and its breeding sites and density were measured in four villages. From Hmaw Inn RHC, Kyow Pin Sakan and Chaung Khawa villages and from Taw Kalut RHC, Ye Kyi and Yun Thwe village were selected to do entomological surveys. Ye Kyi and Kyow Pin Sakan villages had high density of pig farms ie. 80-90% of households had pig farms (61/76 house in Ye Kyi village and 83/92 houses in Kyow Pin Sakan villages) and Chaung Khawa and Yun Thwe villages had low density of pig farms ie. 30-40% of households had pig farms (24/78 houses in Ye Kyi village and 36/89 houses in Chaung Khawa village). Therefore, this study covered two RHC, four villages and 204 pig farmers.

Data collection methods

Mosquitoes were collected from fixed mosquito catching stations between pig farms and human dwellings of both field areas of Hmaw Inn and Taw Kalut RHCs using kanda big mosquito nets (330 x 330 x 180 cm) (K-net) for animal bait. CDC light traps method was used for indoor and outdoor mosquito collection and cow shed collection in the selected areas of four villages. Light traps mosquito catching in cow sheds using big animal bait mosquito nets and WHO sucking tubes was conducted from 18:00 to 06:00 hours of the next day and morning resting collection was done in 5 houses/village at 06:00-07:00 hours for 5 days. Mosquito resting behavior and feeding behavior were recorded.

Larva collection

For identification of breeding sites, larval surveys were conducted in polluted water sources such as brick kilns, ponds, paddy fields domestic wells, stream/creeks and all different types of water holding places, marshes around the irrigation ditches in paddy fields, hyacinth vegetation and water pools in and around three kilometers radius from the study site, by 3 dips/water holding place with WHO dipper.11

Susceptibility test: susceptibility test of Culex adult mosquitoes was done with deltamethrin 0.05%, permethrin 0.75% and cyfluthrin 0.15% using WHO test kit.12

Resting place: resting mosquitoes were searched in indoor and outdoor places of the household and cowshed. The captured larvae and pupae were put in labeled plastic bags and brought back to the laboratory for species identification and colonization.

Identification of mosquitoes: Collected adult mosquitoes and adults emerged from larva survey were identified by species according to different identification keys.13-15

Data analysis

Data from various sources were triangulated for meaningful interpretation. Larval density was calculated by larvae/dip and percentages were computed for adult mosquito density per village by Excel software. Map of the study areas was drawn by GPS device (GPSMap16 Garman, 18x-5HZ software interface application method by an expert).




DISCUSSION
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Japanese encephalitis virus is transmitted to humans through bites from infected mosquitoes of the Culexspecies (mainly Cx. tritaeniorhynchus). Humans, once infected, do not develop sufficient viraemia to infect feeding mosquitoes.16 In the present study of JE vectors surveillance in Letpadan Township, Bago Region, high numbers of pig farms were available in Kyow Pin Sakan and Ye Kyi villages and high density of JE vector Cx. tritaeniorhynchutare available in all study areas, i.e. 5.88%, 34.31%, 59.00%
and 44.68% in Kyout Pin Sakan, Chaung-Khawa, Ye Kyi, and Yun Thwe villages, respectively. Most Cx. tritaeniorhynchusmosquitoes were found in morning resting collection in pig farms and higher bite in night time when pigs were sleeping.

Culextritaeniorhynchuslarvaewere abundantly collected in polluted water pools and paddy fields in all selected villages. Other researchers revealed that main JE vector Culextritaeniorhynchus breeds predominantly in paddyfields and open sunlit temporary and permanent habitats with vegetation and they have average flight range of 1.5 kilo meters.17, 18  Secondary vectors Cx. vishnui were found in high density in adult collection. Other species Cx. quinquefasciatus, Cx. gelidus,Mansonia species and some Anopheles species suchas An. vagus,An. culicifacies, An. tesellatusand An. barbirostris were collected by different collection methods. The natural hosts of the Japanese ence-phalitis virus are birds, not humans, and many people, therefore,believe the virus will never be completely eliminated.18In a study inSouth Korea, the Japanese encephalitis virus was presented in Cx. bitaeniorhynchus mosquitoes.19 Many species of Culexmosquitoes can transmit JE. For Southern Asia, Eastern Asia, and Southeastern Asia, the main vector of JE is Cx. tritaeniorhynchus. For Northern Australia, the main vector is Cx. annulirostris. However, various other secondary vectors may be important.20Vectors observation study in India revealed thatCulicine mosquitoes, mainlyCx. vishnui group (Cx. tritaeniorhynchus, Cx. vishnuiandCx. seudovishnui),are the major vectors of JE in different parts of India. In Anopheles groupsuch as An. Barbirostris, An. Paedi-taeniatus andAn. subpictus isolates and Mansonia group such as Ma. Annulifera,Ma. indiana and Ma. uniformis isolates were found to be JE virus positive.21 Culexvishnui groups are present in many countries of South-East Asia,22and usually found in rural rice-growing and pig-farming regions of Asia as well as at the outskirts of cities in close proximity to human populations.23 Biting rates of both Cx. tritaeniorhynchus and Cx. vishnuiwere observed highest on cattle followed by pig and lowest on human. Culextritaeniorhynchus and Cx. vishnui were observed anthrophophilic mosquitoes. Other researchers revealed that Cx. vishnui subgroup is very common and widespread and are primarily outdoor resting in vegetation and other shaded places but they may also rest indoors summer.24 In the present study, morning resting collection was higher in indoor than in outdoor i.e. 3.82:1 ratio which means both mosquitoes were more endophagic and endophilic than exophagic and exophilic and mostly rested under the hanging clothes on the wall, under the baskets, in opening bags and moist dark places.

Both Culex mosquitoes are principally cattle feeders, though pigs and human feeding were also recorded. Pig farms were very close to human dwelling and some pig farms were situated beside, back and under the houses.
It is a high risk to transmit JE infection to children and adult. Pigs are considered to be the most important amplifying host, providing a link to humans through their nearness to housing.25

A researcher from India revealed that an 87% reduction in mosquito density could be achieved for a per capita cost using community education for vector control.26 In another observation in Assam, India, a sharp reduction in JE zero-conversion rates in people and pigs was achieved when insecticide-treated nets were used in both people and pigs.27

In the present study, primary JE vector Cx. tritaeniorhynchus and secondary vector Cx. vishnui mosquitoes were found to be susceptible to deltamethrin 0.05, permethrin0.75% and cyfluthrin 0.15%. It means that JE vectors can be controlled by LLINs nets.
A population-based case-control study in China found that use of insecticide treated nets was associated with significant reduction in JE cases.28

The knowledge about mosquitoes was found in high percentage (61.6%) of respondents who knew about breeding site of Culex mosquitoes, (i.e. polluted water pools). A study from India observed that knowledge about breeding site of mosquito was poor (36.9%) in their study.29Although Shresthaet al.,30 observed higher awareness level about breeding place (50%), it was agreed with the present study. But not agreed with another study from Karnataka that was observed low level of knowledge about breeding site of mosquitoes.31

Researcher had physically verified the water drainage condition of dwelling in the present study. Most of the houses were in unsatisfactory condition due to polluted water pools behind the house. These were the potential breeding site for mosquitoes and they never removed this polluted water pools although they knew stagnant water could be a potential breeding site for mosquitoes. They prefer to breed in rice fields, and outbreaks of Japanese encephalitis are commonly associated with intensive rice cultivation.32Service33 mentioned that main vector of JE breeds in water with luxuriant vegetation mainly in paddy fields and the abundance is related to rice cultivation, shallow ditches and pools.

Japanese encephalitic risk factors were common across pig farms and farm families in all four villages but there were differences in levels of knowledge and practices of villagers related to JE risk reduction. The findings of the study showed that there were relatively good attitude and practices regarding about JE in local population, 64.8% of respondents heard about JE from health staff followed by from television. Earlier studies reported that radio,34TV,35,36 and newspapers36 as most important sources of knowledge. Similar finding (54%) was reported in Nepal in 2012 at Rupandehi district.37

A KAP study from Malwa district on mosquito-borne disease among students revealed that only 6.5% were aware that JE is a mosquito-borne disease.35 In the present study, the community members well knew that JE transmission occurred by the biting of mosquitoes and 51.1% of the respondents mentioned that JE was infected by mosquitoes bite at night time and some said as close contact with pigs. The community members thought that the transmission of JE was mainly from the pigs and small number of members said as birds and cows.

Most of the people answered the most susceptible host to the transmission of JE was under five years old children and 5-15years children. Most of the respondents could not correctly identify the typical sign and symptoms of JE, most members said as severe headache and high fever and these results agreed with those of Yadav and Ahmad.29 For the prevention of JE transmission in human being, 82.4% of the participants said as sleeping under the mosquito nets and some mentioned burning coil and spraying insecticide although 56.8% of the members believed JE vaccination to human was the effective control method.

Most of the members mentioned that spraying or fumigation with larvicides were most suitable for removing JE vectors and some people said removal of garbage dump. Panditet al.37 showed that people were using one or more methods of personal protective measures against mosquito bite. Most common was repellent followed by mosquito net. Our study contradict these findings because the use of mosquito net was most common (54%) followed by insecticide sprays and mosquito coil which are agreed with the results of JE study in rural areas of Uttar Pradesh, India.29In the present study, Culex mosquito’s larvae were abundantly present in stagnant water pools and in rice field water and also knowledge of respondents about breeding site of Culex mosquito was high (61.6%). Yadav and Ahmad29 revealed that only 36.3% of households agreed that stagnant water can be a potential breeding site for mosquitoes.
A similar study from Pondicherry reported that 70% of households had stagnant wate.38 This type of community favors mosquito breeding in their areas.39 Risk factor: Pig farms, mosquito breeding sources as rice fields and water pools are situated very close to human dwelling (5-15 meters). In each village, 20 to 50% of the households have 1-15 pigs in one to two pig farms and 90% of the pig farms are open type. Main JE vector breeding sites such as polluted water creeks, pools, gutters and rice fields are situated in and beside the villages and also Culexlarvae were abundantly present. Most of the villagers and their family members have not used mosquitoes net when they go to sleep. All he human Dwelling are situated within the flight rangeof JE vector (1.5 kilometer).

Conclusion

Japanese encephalitis is rising throughout Asia, because epidemics are typically noticed only after outbreaks. This study help not only to improve the awareness of JE in the community but also to reduce the transmission risk and to fill the knowledge gaps of stakeholders and community members to implement an integrated one health approach at village level in high risk endemic regions.

Pigs are main host for JE virus, Cx. tritaeniorhynchus adult and larvae were abundantly collected in polluted water pools and rice fields in all selected villages. Old and new JE history was available in these villages. Implementation of a vaccination program for young children, as well as modified agricultural practices, pig vaccination, rigorous monitoring, vector control, and improved living standards can reduce the number of JE cases. This study provides further information on risk of JE transmission in study areas. Environmental and ecological factors are responsible for the spread of JE virus. Therefore, the study recommended that VBDC need to give LLIN nets and health education to all family members to prevent JE transmission in villages.


ACKNOWLEDGMENT
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The authors are thankful to the Ministry of Health and Sports for supporting the IR grant to do this research. We would like to thank Dr. KyawZin Thant, Director-General, Department of Medical Research for permission to do research.  We also thank the staff of Medical Entomology Research Division, Department of Medical Research for providing financial support over the many fruitful years of entomological research.


CONFLICT OF INTEREST
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Competing interests

The authors declare that they have no competing interests.


REFERENCES
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