Japanese Encephalitis (JE), a mosquito borne disease, is the leading cause of viral encephalitis in 14 Asian countries due to its epidemic potential, high case fatality rate and increased possibility of lifelong disability in patients who recover from this dreadful disease. In spite of seriousness of the disease, still only few books are available for ready reference. Hence, this book will be useful for students, entomologists, paramedical staff and vector control managers in public health.
Of the thousand suspected JE deaths in India annually, more than 75% is contributed by Northern India wherein disease transmission failed to be explained based on entomological evidence due to inadequate mosquito surveillance tool used in determining JE vector density. In order to overcome the above problem, Dr Bina Pani Das, the author of this book, developed BPD hop cage method , a simple, cost effective, and operationally feasible surveillance tool specially designed to capture predominantly day resting adult Cx. tritaeniorhynchus mosquitoes, the principal JE vector species in the country from land and aquatic vegetation.

xvii
Contents
1 Japanese Encephalitis and Problem in Vector Surveillance:
An Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Global Scenario . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 Emergence of JE in India. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.4 Magnitude of JE Problem in India. . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.4.1 Trend of JE Occurrence. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4.2 Contribution of JE Cases by States . . . . . . . . . . . . . . . . . . . . 5
1.4.3 Concept of Endemic and Epidemic Districts in India . . . . . . 6
1.5 JE Outbreaks in India. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.6 Clinical Presentation and Diagnosis. . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.6.1 Laboratory Diagnosis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
1.7 Epidemiology of Japanese Encephalitis. . . . . . . . . . . . . . . . . . . . . . . 9
1.7.1 Natural History. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.7.2 Seasonality. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1.8 Vectors of Japanese Encephalitis. . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1.9 Problem Faced While Investigating AES/JE Outbreak in
Northern India . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.10 Research Problem Addressed by the Author and Included in
this Book . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.10.1 Developed a New Sampling Technique for JE Vector
Surveillance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.10.2 Pictorial Key to Common Species of Culex (Culex)
Mosquitoes Associated with JEV in India. . . . . . . . . . . . . 12
1.10.3 Ecological Studies on JE Vectors in Northern India . . . . . 13
1.10.4 Discovery of a New Bio-Control Agent. . . . . . . . . . . . . . . 13
1.10.5 Situation Specific Vector Control Measures. . . . . . . . . . . . 13
1.11 JE Control Programme in India. . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.11.1 Vaccination. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.11.2 JE Vector Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
xviii Contents
2 Mosquito Surveillance Tools Used and Methodology Followed
in Ecological Study on JE Vectors in Northern India . . . . . . . . . . . . . . 17
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.2 Study Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.2.1 Phase 1: Non-Endemic Area In and Around Delhi
(1998 2002). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.2.2 Phase 2: Endemic Area I Karnal District, Haryana
State of India (2002 2004). . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.2.3 Phase 3: JE Endemic Area II Saharanpur District,
Uttar Pradesh State of India (2005 2006). . . . . . . . . . . . . . . 18
2.3 Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.3.1 Metrological Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.3.2 Epidemiological Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.3.3 Sampling of Adult Mosquitoes. . . . . . . . . . . . . . . . . . . . . . . . 19
2.3.4 Sampling of Mosquito Larvae. . . . . . . . . . . . . . . . . . . . . . . . 22
2.3.5 Mosquito Blood Meal Identification . . . . . . . . . . . . . . . . . . . 22
2.3.6 JE Virus Detection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
2.4 Pictorial Key for Identification of Common Species of Culex
(Culex) Mosquitoes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3 Pictorial Key to Common Species of Culex (Culex) Mosquitoes
Associated with Japanese Encephalitis Virus in India. . . . . . . . . . . . . . 25
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.2 Pictorial Key to Commonly Encountered Species of Culex (Culex)
Mosquitoes Associated with Japanese Encephalitis in India. . . . . . . 32
References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
4 BPD Hop Cage Method for Effective JE Vector Surveillance. . . . . . . . 43
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
4.2 Standardisation of BPD Hop Cage Method for Sampling
JE Vectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
4.3 Identification of Various Natural Day Resting Places of
Cx. tritaeniorhynchus in and Around Delhi. . . . . . . . . . . . . . . . . . . . 48
4.4 Comparative Efficacy of Drop Net, Hand Catch and BPD
Hop Cage Method for Monitoring JE Vector Abundance . . . . . . . . . 50
4.5 Use of BPD Hop Cage Method in JE Vector Surveillance and
Outbreak Investigation of JE/AES. . . . . . . . . . . . . . . . . . . . . . . . . . . 53
4.5.1 JE Vector Surveillance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
4.5.2 Outbreak Investigation of AES/JE. . . . . . . . . . . . . . . . . . . . . 56
References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
5 Ecology of Culex tritaeniorhynchus in and Adjoining Areas
of Delhi, Non endemic Area in Northern India, with Special
Reference to Chilodonella uncinata as a Bio-control Agent. . . . . . . . . . 61
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Contents xix
5.2 Seasonal Abundance of Culex tritaeniorhynchus in and
Around Delhi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
5.3 Resting Preference of Culex tritaeniorhynchus in and
Around Delhi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
5.4 First Time Detection of Overwintering Phenomenon in Culex
tritaeniorhynchus in India . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
5.5 Breeding Habit of Culex tritaeniorhynchus in and Around Delhi. . . 67
5.6 Natural Microbial Organisms Found Infecting JE Vector Larvae
in and Around Delhi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
5.6.1 Discovery of a New Microbial Control Agent for Mosquito
Vectors of Human Diseases. . . . . . . . . . . . . . . . . . . . . . . . . . 68
5.6.2 Events that Lead to the Invention. . . . . . . . . . . . . . . . . . . . . . 69
5.6.3 Problems Encountered in Detection, Isolation and
Identification of the Causative Organism. . . . . . . . . . . . . . . . 69
5.6.4 Biological Characteristics of Chilodonella uncinata. . . . . . . 70
5.6.5 Role of Ch. uncinata on the Population Dynamics of
Cx. tritaeniorhynchus Mosquito in Nature. . . . . . . . . . . . . . . 73
5.6.6 Colonization of Ch. uncinata Under Laboratory Condition. . . 76
5.6.7 Formulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
5.6.8 Mode of Entry of Ch. uncinata Inside the Host Body
and Subsequent Histopathology. . . . . . . . . . . . . . . . . . . . . . . 78
5.6.9 Filling of National and International Patents. . . . . . . . . . . . . 79
5.7 Situation Specific Vector Control Measures in and Around Delhi. . . 79
5.7.1 Control Strategies in Delhi. . . . . . . . . . . . . . . . . . . . . . . . . . . 80
5.7.2 Control Strategies in Paddy Growing Areas of Sonipat
District (Haryana). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
6 Ecology of Culex tritaeniorhynchus in Karnal District
(JE Endemic Area), Haryana State in Northern India. . . . . . . . . . . . . 85
6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
6.2 JE in Haryana State/Karnal District. . . . . . . . . . . . . . . . . . . . . . . . . . 87
6.3 Ecological Study of JE Vectors in Karnal District. . . . . . . . . . . . . . . 87
6.3.1 Prevalence of Cx. tritaeniorhynchus, the Principal
JE Vector Species in the Karnal District. . . . . . . . . . . . . . . . . 88
6.3.2 Seasonal Abundance of Cx. tritaeniorhynchus in Study
Sites in Karnal District. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
6.3.3 Resting Habit of Vector Species Study in Areas
of the District. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
6.3.4 Seasonal Abundance of Larval Stages of
Cx. tritaeniorhynchus in Karnal District . . . . . . . . . . . . . . . . 92
6.3.5 First Time Detection of JE Virus in Vector Species from
Haryana State. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
6.4 Spread of JE to New Areas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
6.5 JE Control Options. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
6.5.1 Mosquito Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
xx Contents
6.5.2 Control of Pigs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
6.5.3 Vaccination. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
7 Ecology of Mosquito Vectors of Japanese Encephalitis Virus in
Saharanpur District (JE Endemic Area), Uttar Pradesh State in
Northern India. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
7.1.1 Mosquito Control Strategy Adopted by Saharanpur District. . . 104
7.1.2 Need for Ecological Study of JE Vectors in
Saharanpur District. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
7.2 Epidemiological Profile of Japanese Encephalitis in Uttar Pradesh
State/Saharanpur District. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
7.2.1 Magnitude of JE Problem in Uttar Pradesh State. . . . . . . . . . 105
7.2.2 Japanese Encephalitis Problem in Saharanpur District . . . . . 106
7.3 Mosquito Fauna of Saharanpur District Including Notes on
their Medical Importance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
7.3.1 Topography of Saharanpur District . . . . . . . . . . . . . . . . . . . . 108
7.3.2 Study Sites. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
7.3.3 Features of Affected and Unaffected Study Sites. . . . . . . . . . 112
7.3.4 Adult Mosquito Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
7.3.5 Medical Importance of Mosquitoes of Saharanpur
District. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
7.4 Comparative Seasonal Abundance of Culex tritaeniorhynchus
from Affected and Unaffected Study Areas of Saharanpur
District. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
7.4.1 Proportion of Members of Culex vishnui Subgroup
Taken in Affected and Unaffected Villages . . . . . . . . . . . . . . 122
7.4.2 Comparative Seasonal Abundance of Cx. tritaeniorhynchus,
Primary JE Vector Species in Saharanpur District. . . . . . . . . 122
7.5 Shifting Pattern in the Resting Habit of Cx. tritaeniorhynchus
in Saharanpur District. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
7.6 Feeding Behaviour of Cx. tritaeniorhynchus in
Saharanpur District. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
7.7 Brick Kiln Industry and Its Role in JE Vector Breeding Potential
in Saharanpur District. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
7.8 Detection of Natural Vertical Transmission of JE Virus in
Vector Mosquitoes of Saharanpur District. . . . . . . . . . . . . . . . . . . . . 134
7.9 Seasonal Variations in Minimum Infection Rates of JE Virus in
Vector Mosquitoes in Relation to Seasonal Abundance of
Cx. tritaeniorhynchus in Saharanpur District. . . . . . . . . . . . . . . . . . . 136
7.10 JE Vector/Virus Surveillance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
7.10.1 JE Vector Surveillance. . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
7.10.2 JE Virus Surveillance in Mosquitoes. . . . . . . . . . . . . . . . . 138
7.11 JE Vector Control/Management Strategies for
Saharanpur District. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
7.11.1 Protection of Human . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
7.11.2 Reduction of Adult Vector Population. . . . . . . . . . . . . . . . 139
7.11.3 Measures to Protect Pigs . . . . . . . . . . . . . . . . . . . . . . . . . . 139
7.12 JE Vaccination Programme in Saharanpur District . . . . . . . . . . . . . 140
References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Index. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
Contents xxi
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