This presentation is prepared as part of the Course assignment of “Epidemiology of Diseases and Health Problems” for the Master's Degree of Public Health (MPH), Pokhara University and can be used as reference materials. The content and facts included in the presentation are as of information available till December 2022 and no conflict of interest is associated with the presentation. The presentation is prepared by Sagar Parajuli.
💚 Punjabi Call Girls In Chandigarh 💯Lucky 🔝8868886958🔝Call Girl In Chandigarh
Epidemiology of Malaria & Dengue_Sagar Parajuli.pptx
1. Epidemiological Perspective of Malaria and Dengue
& Review of National programs and activities
Sagar Parajuli
MPH Second Semester 2022
School of Health & Allied Sciences
Pokhara University
2. 2/7/2023 2
Presentation Outlines
• Introduction (Malaria & Dengue)
• Epidemiological Determinants (Agent, Host and Environment)
• Distribution (Global, Regional, National)
• Prevention, Control and Treatment Activities
• Response towards Malaria and Dengue (WHO & Government of Nepal);
National policies and programs review
Presentation followed by discussion
3. 2/7/2023 3
Introduction to Malaria (ICD 11, 1F40-1F4Z)
• Etymologically, the term malaria derived as Italian word as mala-bad, aria- air
is a protozoan infection, dominantly in tropics and sub-tropics
• Acute febrile illness, caused by Plasmodium parasites spread by bite of an
infected female Anopheles mosquito
• Plasmodium 5 species- P. falciparum, P. ovale, P. vivax, P. malariae, P.
knowlesi-zoonotic malaria
• P. falciparum known as deadliest malaria parasite (malignant tertian) and P.
vivax as dominant malaria parasite poses the greatest threat of malaria
(benign tertian)
4. 2/7/2023 4
Epidemiological Determinants
• Agent: Plasmodium parasites, 5 species
• Vector: Female Anopheles Mosquito ‘invertebrate definite host’
• Host Factors: Human as ‘intermediate host’ and ‘reservoir’ as well
1. Genetic Factors: Biological advantage for people having sickle cell trait,
thalassemia, G6PD deficiency to P. falciparum, people with duffy blood
type to P. vivax
2. Immunological Factors: Newborn of mother infected with malaria
developing acquired immunity for first few months of birth
3. Behavioral factors
Risk population: living in endemic and slum areas, pregnant women, traveler,
children
5. 2/7/2023 5
Epidemiological Determinants
• Environmental Factors: vital for vector and parasite growth and
development, as well as for creating contact environment between agent, host
and vector
1. Climate-based factors: rainfall
2. Temperature- 16-34 Degree Celsius with optimal transmission at 25
3. Precipitation; frequency, duration and intensity
4. Waste water management, breeding places like damp and waterlogged
Peak season and months: May-July, September-December following end of dry and
wet season, dominant during rainy season due to waterlogged and damp places
suitable for mosquito breeding
6. 2/7/2023 6
Transmission Dynamics
• Mode of transmission: ‘Bite, Blood, Birth’
Through bite of an infected female Anopheles mosquito (during dusk, early
night hours, early morning hours), Blood Transfusion & share of needles,
vertical transmission to lesser extent ‘congenital malaria’
• Incubation Period: 7-14 days for P. falciparum, 8-14 days for P. vivax and P.
ovale, 7-30 days for P. malariae
• Period of Communicability: as long as infective gametocytes present in
blood; not more than a year for P. falciparum, 1-2 years for P. vivax and P.
ovale, 7 months-3 years for P. malariae (EWARS Guideline)
8. • Mosquito stage
(Sporogonic cycle)
• Human Liver stage
(Exo-erythrocytic
cycle)
• Human Blood stage
(Erythrocytic cycle)
2/7/2023 8
Plasmodium Life Cycle
9. • Intermittent Periodic fever; a
characteristic paroxysmal malarial
fever with ‘cold, hot, and wet’
phases, usually after 10-15 days
of mosquito bite
• Headache, Vomiting, Chills
• Anemia, Splenomegaly
• Dry (Nonproductive cough)
Symptoms repeat 48-72 hrs in a cyclic manner.
Based on symptoms and complications, malaria
categorized as uncomplicated and complicated
(severe) malaria.
2/7/2023 9
Clinical presentations
11. 2/7/2023 11
Global Status- Malaria
• Globally, estimated 247 million cases in 2021 from 84 malaria endemic
countries, increased from 245 million cases in 2020
• Malaria case incidence globally- 59 cases per 1000 population at risk
• 29 countries accounted for 95% malaria cases globally; Nigeria (27%),
Democratic Republic of Congo (12%)
• South East Asia accounted for 2% burden of malaria globally, with 76%
case reduction and 82% reduction in case incidence, case incidence reported in
2021- 3 cases per 1000 population at risk
Source: Global Malaria Report, WHO 2020
12. Malaria Microstratification
2021, Annual Report-
DoHS 078/79
• 22 High Risk Wards
• 69 Moderate Risk
Wards
• Malaria risk shift to
upper hilly river valley
• 82% high risk burden
and 94% of moderate
risk burden
concentrated in Karnali
and Sudurpaschim
2/7/2023 12
National Status- Malaria
Source: DoHS Annual Report 077/78
15. 2/7/2023 15
National Status- Malaria
0
200
400
600
800
1000
1200
2075/76 2076/77 2077/78
1069
619
377
440
102 66
625
517
311
Indigenous and Imported Malaria Cases
Total Positive cases Indigenous cases Imported cases
• 90 % reduction in
Indigenous Malaria Cases in
FY 077/78 compared to FY
71/72
• Annual Blood Examination
Rate (ABER) decreased to
1.32 %
• Annual parasite incidence
rate-0.03 per 1000 population,
slide positivity rate- 0.24%
• 86.47 % P. vivax cases
• 13.52 % P. falciparum cases
• High malaria cases reported in
Kailali, Kanchanpur, Banke,
Achham, Surket and Baitadi
Source: DoHS Annual Report 077/78
16. 2/7/2023 16
Global Malaria Control Activities
•Era
• Period
• Major achievement
Era Period Major achievement
Eradication 1955-1969 Malaria control by Insecticide Spray
Resurgence 1969-mid 1980 Establishment of microscopic center
and treated by sign and symptoms
Control 1980 onwards Research activities, IRS, Medical
Recording
Roll back 1998 onwards Epidemic control, surveillance
strengthening, Elimination strategy
17. 1950
• 2 Million cases (40% of total population) and 10-15 % Deaths
1954
• IBDCP; started malaria control activities, with support of USAID (USOM)
1958
• Malaria Eradication Program; first national public health program
1978
• Redefined and revised as ‘Malaria Control Program’
1993
• Adopted WHO supported Global Malaria Eradication Strategy (GMCS)
1998
• Roll back malaria (RBM) launched, initially in 12 endemic districts
17
Chronological Activities: Malaria Eradication to Control, Nepal
18. • National Malaria Laboratory
Technical Steering Committee &
TWG- EDCD, NPHL, VBDRTC
• Health Office as focal point at
district level
• Malaria Microscopy Center Testing
service at HP, PHCCs, Primary
Hospital
• PACD, RACD & Community-based
testing as per necessity
2/7/2023 18
Institutional Framework
Source: National Malaria Laboratory Plan
19. • Case Notification, Surveillance and Information System: Reporting
through DHIS 2, MDIS, EWARS (Immediate reporting of single case of
severe and complicated malaria), within 24 hrs and 74 hrs action
1. Case-based surveillance
2. Integrated Entomological Surveillance
3. Vector survey
• Case Identification and Detection: Case investigation, Foci investigation,
PACD, RACD & Community-based testing as per necessity
• Risk mapping: Micro-stratification
• Prevention & Promotion activities: Distribution of LLIN, ITN,
Development of IEC and SBCC materials, celebration of Malaria Day
2/7/2023 19
National programs and activities
20. • Capacity building of HSPs and stakeholders: Palika level, district
level, women group focused, FCHVs focused
• Research: Operational research on malaria, vectors and parasites
• Interventions: Vector control interventions
• System strengthening: Supportive supervision
• Specific activity for imported malaria: Testing at PoEs/GC (Point of
Entry and Ground Crossing)
2/7/2023 20
National programs and activities
21. • Malaria Disease Information System (MDIS); developed by Ekbana for
EDCD for Malaria Control Program
• In operation, for case notification and analysis through two systems;
mobile application and CMS system
2/7/2023 21
MDIS- A short brief
24. Vision: Malaria Elimination in Nepal by 2025
Mission: Ensure universal access to quality
assured malaria services for prevention,
diagnosis, treatment and prompt response in
outbreak.
Goal: Reduce the indigenous malaria cases to
zero by 2022 and sustain thereafter.
Objectives: To ensure proportional and
equitable access to quality assured diagnosis and
treatment in health facilities as per federal
structure and implement effective preventive
measures to achieve malaria elimination
2/7/2023 24
National Malaria Strategic Plan (2014-2025)
Surveillance &
Information System
Vector Control
Intervention
Early Diagnosis
and treatment
Leadership &
Community
engagement
Strengthening
technical and
managerial
capacities
25. 2/7/2023 25
WHO Response towards Malaria
• WHO Committee: MPAG, VCAG, TAG-MEC
• Development of ‘Global Technical Strategy for Malaria (2016-2030)’-
technical framework for all malaria endemic districts
Target: Reduce case incidence and malaria mortality by 90% in 2030
Eliminate malaria in at least 35 endemic countries by 2030
• Global Malaria Programme; providing technical support and assistance to
country programs
• SDG Target 3.3: “By 2030, end the epidemics of AIDS, tuberculosis, malaria
and neglected tropical diseases and combat hepatitis, water-borne diseases and
other communicable diseases.”
26. • ABCD strategy; Awareness, Bite prevention,
Chemoprophylaxis, Diagnosis
• Surveillance; Identification, detection and
treatment
• Preventive chemotherapies: PMC, SMC,
IPTp, IPTsc, PDMC, MDA
• Interventions: Vector-control, IVM, IRS
• Health Promotion; Use of LLIN, ITNs
• Health Education
• Specific Protection: Vaccine (recommended
from October 2021) RTS,S/AS01 malaria
vaccine
2/7/2023 26
Prevention, Control and Management
27. Sagar Parajuli
MPH Second Semester 2022
School of Health & Allied Sciences
Pokhara University
Epidemiological Perspective of Dengue & Review
of National programs and activities
28. 2/7/2023 28
Introduction to Dengue (ICD 11, 1D20-1D2Z)
• An acute mosquito-borne arboviral disease caused by dengue virus
(DENV), dominantly found in tropical and sub-tropical regions
• Transmitted through bite of an infected Aedes mosquito, mainly by
Ae. aegypti and to lesser extent by Ae. albopictus
• Dengue virus (DENV) are of 4 serotypes; DEN-1, DEN-2, DEN-3, DEN-4
• Infection with one serotype gives lifelong immunity to that serotype but only
short-term immunity to other serotypes (cross-immunity is partial and
temporary)
• Subsequent infection increases risk of severe dengue fever. Severe Dengue
first time reported in 1950 during epidemic in Philippines and Thailand
29. 2/7/2023 29
Epidemiological Determinants
• Agent: Dengue Virus; DEN-1, DEN-2, DEN-3, DEN-4, RNA virus of
Flaviviridae
• Vector: Female Aedes aegypti Mosquito ‘invertebrate primary vector’
anthropophilic nervous feeder and Aedes albopictus as ‘secondary vector’
aggressive feeder
• Host Factors: Human as ‘intermediate host’ and ‘reservoir’ as well, can occur
at any age irrespective of sex, in endemic areas
• Environmental Factors: Climatic factors (rainy, summer and spring), rainfall,
temperature and humidity. 16 ͦ C - 30 ͦ C temperature and the relative humidity of 60-
80%.
Risk population: living in endemic areas, pregnant women, traveler, children
30. 2/7/2023 30
Transmission Dynamics
• Mode of transmission: ‘Bite, Blood, Birth’
1. Through bite of an infected female Aedes mosquito (daytime feeder; early
in the morning 2hrs after sunrise, evening before sunset),
2. Blood Transfusion & share of needles,
3. Vertical transmission to lesser extent (perinatal transmission and
peripartum maternal infection)
4. Transovarial transmission reported among vectors as well
• Incubation Period: ranges from 3-14 days, typically 5-7 days
• Period of communicability: No person to person transmission, 3-5 days
before end of febrile period and 8-12 days mosquito after viremic blood
meal
33. • Dengue cases ranges from asymptomatic to mild
to severe. An estimated 1 in 4 dengue virus
infections are symptomatic.(CDC)
• Undifferentiated dengue fever
• Classic dengue fever ‘breakbone fever’ (Fever,
headache, muscle and join pain, nausea,
vomiting, rash after 4-5 days of fever,
hemorrhagic manifestations)
• Dengue Hemorrhagic Fever (DHF); bruises,
epistaxis, gum and GI bleeding
• Dengue Shock Syndrome; Hypotension
Approximately 1 in 20 patients with dengue virus
disease progress to develop severe dengue. (CDC)
2/7/2023 33
Clinical presentations
36. 2/7/2023 36
Clinical presentations; phases
Febrile phase (2-7 days, can be biphagic): Sudden onset of fever accompanied
by headache, retro-orbital pain, generalized myalgia and arthralgia, flushing of the
face, anorexia, abdominal pain and nausea, Rash on the trunk, on the medial aspect
of the arms and thighs, and on plantar and palmar surfaces
Critical phase (24-48 hrs): Begins with defervescence, Persistent vomiting and
severe abdominal pain , Increasingly lethargic, weakness, dizziness or postural
hypotension occur during the shock state, spontaneous mucosal bleeding
Increasing liver size and a tender liver is frequently observed, rapid and
progressive decrease in platelet count, plasma leakage
Convalescent phase: Plasma leakage subsides and begins to reabsorb extravasated
intravenous fluids, hemodynamic status stabilizes
38. 2/7/2023 38
Global Status- Dengue
• Globally estimated 100-400
million infections occurs per
year
• 80% mild and asymptomatic
• Dengue cases increased by 8
fold in last two decades
• Dengue Epidemic in more
than 100 countries (before
1970 only in 9)
• Highest cases in 2019
Source: WHO Factsheet 2022
39. 2/7/2023 39
Global Status- Dengue
• In 2020/21, Dengue
reported from Asia,
Africa, America,
Caribbean, and
Pacific region.
• Five countries with
highest cases
1. Brazil
2. Paraguay
3. Mexico
4. Vietnam
5. Malaysia
Source: WHO Factsheet 2022
40. 2/7/2023 40
South East Asia Status- Dengue
Categories A
Bangladesh, India, Indonesia,
Maldives, Myanmar, Sri Lanka,
Thailand, Timor-Laste
1. Major Public Health
Problem
2. Leading cause of
hospitalization and death
among children
3. Hyperendemicity with all 4
Serotypes circulating in
urban areas
4. Spreading to rural areas
Categories B
Bhutan, Nepal
1. Endemicity Uncertain
2. First reported case in
Bhutan and Nepal
Categories C
DPR Korea
1. No evidence of
endemicity
• South East Asia accounts for more than
half burden of dengue in the world.
• From 2015 to 2019, dengue cases in
SEA region increased by 46% whereas
deaths decreased by 2% (WHO)
41. Trend of Dengue cases in
Nepal (2004-2022)
• Dengue first reported in
2004 in Nepal
• DENV1 and DENV2
contributing to
Dengue Outbreak in
Nepal (EDCD 2019)
• Outbreak reported
mostly during
September
• January-September
2022, CFR 0.13%
2/7/2023 41
National Status- Dengue Trend
Source: Dengue situation Report 2022, EDCD
42. 2/7/2023 42
National Status- Dengue 2022
#Situation Report Dengue, EDCD
2022
• Total National cases: 54232
• Highest no of cases reported from
Bagmati, Lumbini and Province 1
• Bagmati cases -78.2% and 68.4 % deaths
(WHO 2022)
Source: Dengue situation Report 2022, EDCD
44. 2/7/2023 44
National Status- Dengue 2022
Number of Dengue
cases reported from
districts of Nepal from
1 January- 28
September 2022.
45. Goal: To reduce the morbidity and mortality due to dengue fever, dengue
hemorrhagic fever (DHF) and dengue shock syndrome (DSS)
Objectives
• To develop an integrated vector management (IVM) approach for prevention
and control
• To develop capacity on diagnosis and case management of dengue fever,
DHF and DSS
• To intensify health education and IEC activities
• To strengthen the surveillance system for prediction, early detection,
preparedness and early response to dengue outbreaks
2/7/2023 45
National Dengue Control Program
46. • Case Notification, Surveillance and Information System: Reporting
through DHIS 2, EWARS (Immediate reporting of single case of clinical
dengue), within 24 hrs
1. Case-based surveillance
2. Entomological Surveillance (A. aegypti identified in 5 peri-urban areas of
terai; Kalilali, Chitwan, Parsa, Dang and Jhapa)
• Case Identification and Detection: Dengue testing at Health Facilities &
Community-based testing as per necessity, Mobilization of RRT
• Risk mapping and identification of population at risk
• Prevention & Promotion activities: Development of IEC and SBCC
materials, Distribution of LLIN and IBN
2/7/2023 46
National programs and activities
47. • Capacity building of HSPs and
stakeholders: Palika level, district
level, women group focused,
FCHVs focused
• Research: Operational research on
dengue, vectors and parasites
• Interventions: Vector control
interventions (search and destroy)
• System strengthening: Supportive
supervision
2/7/2023 47
National programs and activities
48. • Case Definition; Dengue without warning signs, with warning signs, severe
dengue (WHO classification)
• Case Definition; suspected, probable, confirmed
• Surveillance categories
1. Passive Disease surveillance
2. Enhanced Disease surveillance
3. Syndromic surveillance
4. Sentinel surveillance and active case finding
5. Vector surveillance
2/7/2023 48
Surveillance for Dengue
50. 2/7/2023 50
WHO Response towards Dengue
• supports countries in the confirmation of outbreaks
• provides technical support and guidance to countries for the effective
management of dengue outbreaks
• provides training on clinical management, diagnosis and vector control
• formulates evidence-based strategies and policies
• support countries in the development of dengue prevention and control
strategies and adopting the Global Vector Control Response (2017-2030)
• publishes guidelines and handbooks for surveillance, case management,
diagnosis, dengue prevention and control for Member States.
51. Level of actions recommended as per National Guideline on Prevention,
Management and Control of Dengue in Nepal
• Household level; Use of personal protection measures, mosquito repellants and
tight fitting mesh/screens on windows and doors, elimination of mosquito
breeding in and around the house
• Community level; Community awareness program, basic sanitation measures,
eliminating outdoor breeding sites, promoting use of insecticide treated nets to
• Institutional level; Early case detection and treatment, source elimination
activities, notification of fever case (suspected/confirmed), entomological
surveillance
2/7/2023 51
Prevention, Control and Management
52. • Chemical Control
• Biological control
• Environmental
management;
modification,
manipulation, change in
human habitation or
behavior
2/7/2023 52
Prevention, Control and Management
A vaccine to prevent dengue (CYD-TDV, Dengvaxia®) is licensed and available in 20 countries
for people ages 9–45 years old. The World Health Organization recommends that the vaccine only
be given to persons with confirmed prior dengue virus infection. (CDC)
54. • National Malaria Strategic Plan (2014-2025)
• Malaria Laboratory Manual 2021
• Microstratification of Malaria in Nepal
• National Malaria Laboratory plan (2020-2025)
• National Malaria Surveillance Guideline 2019
• National Malaria Treatment Protocol 2019
• Interim guidance for continuing malaria services during COVID19 pandemic
in response to 40% mean reduction in malaria testing (Source: Interim guidance for
Malaria services in COVID19)
• National Guideline on Prevention, Management and Control of Dengue in
Nepal, 2019
• Global strategy for Dengue prevention and control 2021- 2030
2/7/2023 54
Guiding Documents
55. 1. Castro, M. C. (2017). Malaria Transmission and Prospects for Malaria Eradication: The Role of the Environment. Cold Spring
Harbor Perspectives in Medicine, 7(10), a025601. https://doi.org/10.1101/cshperspect.a025601
2. CDC. (2021, September 13). Dengue Clinical Presentation | CDC. Centers for Disease Control and Prevention.
https://www.cdc.gov/dengue/healthcare-providers/clinical-presentation.html
3. Huang, H.-W., Tseng, H.-C., Lee, C.-H., Chuang, H.-Y., & Lin, S.-H. (2016). Clinical significance of skin rash in dengue fever:
A focus on discomfort, complications, and disease outcome. Asian Pacific Journal of Tropical Medicine, 9(7), 713–718.
https://doi.org/10.1016/j.apjtm.2016.05.013
4. Midekisa, A., Beyene, B., Mihretie, A., Bayabil, E., & Wimberly, M. C. (2015). Seasonal associations of climatic drivers and
malaria in the highlands of Ethiopia. Parasites & Vectors, 8, 339. https://doi.org/10.1186/s13071-015-0954-7
5. Nguyen, N. M., Kien, D. T. H., Tuan, T. V., Quyen, N. T. H., Tran, C. N. B., Thi, L. V., Thi, D. L., Nguyen, H. L., Farrar, J. J.,
Holmes, E. C., Rabaa, M. A., Bryant, J. E., Nguyen, T. T., Nguyen, H. T. C., Nguyen, L. T. H., Pham, M. P., Nguyen, H. T.,
Luong, T. T. H., Wills, B., … Simmons, C. P. (2013). Host and viral features of human dengue cases shape the population of
infected and infectious Aedes aegypti mosquitoes. Proceedings of the National Academy of Sciences of the United States of
America, 110(22), 9072. https://doi.org/10.1073/pnas.1303395110
•
2/7/2023 55
References
56. 6. Nishiura, H., & Halstead, S. B. (2007). Natural History of Dengue Virus (DENV)—1 and DENV—4 Infections: Reanalysis of
Classic Studies. The Journal of Infectious Diseases, 195(7), 1007–1013. https://doi.org/10.1086/511825
7. Prevention, C.-C. for D. C. and. (2020, July 16). CDC - Malaria—About Malaria—Biology.
https://www.cdc.gov/malaria/about/biology/index.html
8. Rijal, K. R., Adhikari, B., Adhikari, N., Dumre, S. P., Banjara, M. S., Shrestha, U. T., Banjara, M. R., Singh, N., Ortegea, L., Lal,
B. K., Thakur, G. D., & Ghimire, P. (2019). Micro-stratification of malaria risk in Nepal: Implications for malaria control and
elimination. Tropical Medicine and Health, 47(1), 21. https://doi.org/10.1186/s41182-019-0148-7
2/7/2023 56
References
For more: Falciparum malaria is potentially life-threatening. Patients with severe falciparum malaria may develop liver and kidney failure, convulsions, and coma. Although occasionally severe, infections with P. vivax and P. ovale generally cause less serious illness, but the parasites can remain dormant in the liver for many months, causing a reappearance of symptoms months or even years later.
A certain species of malaria called P. knowlesi has recently been recognized to be a cause of significant numbers of human infections. P. knowlesi is a species that naturally infects macaques living in Southeast Asia. Humans living in close proximity to populations of these macaques may be at risk of infection with this zoonotic parasite.
P. vivax and P. ovale have stages (“hypnozoites”) that can remain dormant in the liver cells for extended periods of time (months to years) before reactivating and invading the blood. Such relapses can result in resumption of transmission after apparently successful control efforts, or can introduce malaria in an area that was malaria-free
Vector: Anopheles masculatus, An. Annularis, An. Minimus,
For more information: The parasites have a tougher time developing when mosquitoes are too warm. But if a mosquito picks up the parasites from blood at around dusk, those parasites have more hours of cooler nighttime temps to complete their development.
Source: Annual Report, Department of Health Services
For information: MPAG: Malaria Policy Advisory Group, VCAG: Vector Control Advisory Group
PMC- Perennial Malaria Chemoprevention, SMC- Seasonal Malaria Chemoprevention, Intermittent preventive treatment of malaria in pregnancy (IPTp) and school-aged children (IPTsc), post-discharge malaria chemoprevention (PDMC) and mass drug administration (MDA)
