Prevention and Control of Dengue

1. Dengue- Prevention & Control
Dr Geetha M

2. Synopsis
• Distribution and determinants
• Dynamics of Dengue transmission with
Dengue prevention & control
• Vector- Aedes spp.
• Vector control – Integrated Vector
management
• Recent initiatives & Advances in Dengue
control

3. Dengue occurs throughout much of
the tropical world

4. Dengue: Determinants- A snapshot
Agent
(virus)
Environment
(Abiotic &
biotic)
Host
(Man &
mosquito)

5. Chain of infection
Source or
Reservoir
Modes of
transmission
Susceptible
host

6. Exposure
Infection
Disease
Death Recovery
V
e
c
t
o
r
Dengue
Aedes
aegypti
Reduce human-
vector contact
To control
larval habitats
WHO/CSR
Early diagnosis &
proper management
•Controlling
reservoir
•Interruption of
transmission
•Protection of
susceptible host

7. Prevention & control of Dengue
• To control larval habitats
• To reduce human-vector contact
• To ensure prompt diagnosis of cases of fever &
appropriate treatment
No specific antiviral treatment or vaccine
against Dengue is available
INTEGRATED VECTOR MANAGEMENT

8. Aedes mosquito

9. Aedes mosquitoes
• Tiger mosquitoes
• Day biter
• Breeds inside & around
the house
• Bites repeatedly
• Container mosquitoes
• Eggs can live without
water for more than
one year

10. Aedes mosquitoes
Aedes aegypti
• Highly domesticated
• Strongly anthropophilic
• Nervous feeder
• Discordant species
• Diurnal species
Aedes albopictus
• Has feral moorings
• Feeds on animals &
humans
• Aggressive feeder
• Concordant species

14. Chain of Dengue transmission

15. Risk factors associated with DF/DHF
• Demographic & societal changes
• Water supply
• Solid waste management
• Mosquito control infrastructure
• Consumerism
• Increased travel & globalization of trade
• Microevolution of viruses

19. Disease mostly occurs in the rainy season and
immediately afterwards (July to October) in
India

20. Integrated vector management
• Prevent mosquito breeding
• Prevent mosquito-human contact

21. Integrated Vector Management (IVM)
A rational decision-making process for the
optimal use of resources for vector control
• Improved efficacy
• Cost-effectiveness
• Ecological soundness
• Sustainability

22. IVM Strategy- 5 elements
• Integrated approach
• Evidence-based decision-making
• Intra- and inter-sectoral collaboration
• Advocacy, social mobilization & legislation
• Capacity building

23. Integration in IVM
• Collaboration within health sector and with
other sectors through the optimal use of
resources, planning, monitoring and decision-
making.
• Integration of non-chemical and chemical
vector control methods
• integration with other disease control
measures.

24. ANTILARVAL MEASURES

25. Vector control
• Environmental management
• Chemical control
• Biological control

26. Environmental management
• Aim: to prevent or minimize vector
propagation and human contact with the
vector-pathogen
Environmental modification
Environmental manipulation
Changes to human habitation or behaviour

27. Environmental modification
• Improvement of water supply and water-
storage systems
• Mosquito-proofing of water-storage
containers
• Solid waste management
• Street cleansing
• Building structures

28. Environmental manipulation

31. Changes to human habitation or
behaviour
Actions to reduce
human–vector contact
• Mosquito screens
• Mosquito nets
• Mosquito repellent
sprays, creams, coils,
mats or liquids

32. Biological control
• Larvivorous fish:
Gambusia affinis &
Poecilia reticulata (Guppy
fish) can be obtained
from local administrative
bodies
• Can be used in burrow
pits, sewage oxidation
ponds, ornamental
ponds, cisterns & farm
ponds

33. Biological control
• Endotoxin-producing
bacteria, Bacillus
thuringiensis serotype
H-14 (Bt H-14) &
Bacillus sphaericus
found to be an effective
mosquito control agent.

34. Chemical control
• 1% Temephos (Abate)
sand granules: an
insecticide to kill larvae
in water; about 5 g for
50 litres of water
• Methoprene briquettes:
1 briquette for 284
litres of water

35. Chemical control
• Insect growth regulators
(IGRs)
• Interfere with chitin
synthesis
• 2 compounds
recommended under
programme
– Pyriproxifen
– Diflubenzuron
• Pheremones as ‘Attract &
kill approach’

36. ANTI-ADULT MEASURES

37. Residual spray & space spray
• Destruction of flying
mosquitoes by contact
with insecticides in the
air
• Don’t forget to spray
behind photo-frames,
curtains, calendars,
corners of house
• Supplement larval
source management
during outbreaks

38. Residual spray & space spray
• Limited evidence for
sustained impact
• Not cost-effective for
routine delivery during
outbreaks
• Efficacy variable
• During emergency, every 2–
3 days for 10 days
• Then once or twice/ week
to sustain suppression of
adult vector population
Don’t turn away spray workers

39. DISEASE SURVEILLANCE

40. Disease surveillance
Epidemiological surveillance
• Passive
• Active
• Event-based
Entomological or Vector surveillance
• Larval surveys
• Pupal/ demographic surveys
• Adult surveys

41. Surveillance tools & Indicators

42. Oviposition traps

43. IVM- Other components
• Community participation
• Model development
• Social mobilization
• Health education
• Intersectoral coordination
• Legislative support

44. When to implement? Where to
implement?
• Background interventions in endemic areas
• Scaling up & additional interventions during
outbreaks
• Early warning systems

45. Who will deliver?
• All hospitals, health facilities
• Municipalities, urban centres,
PRI
• Urban VBD scheme
• MoDWSS, Water supply
companies
• MoHUPA
• MoAFW, Plantation owners
• MIB, Mass media
• Municipalities & waste
collection companies
• PWD
• Research Institutions, NGOs
• Schools & workplaces
• IMD
• Tyre manufacturers , sellers
• Fisheries
• Ministry of Road transport
• Ministry of Railways
• Ministry of Environment,
Forests & climate change
• Sea & air ports
• MoHRD
• Local Govt.
• Community

46. Vector control- Routine control
At all settings At certain
settings
Personal
protection
•Container larviciding using
insecticides (temephos) or
microbial larvicides
•Environmental modification
•Environmental manipulation
•Social mobilisation campaigns
•Insecticide treated curtains
•Screening of doors & windows
•Legislation
•LLINs
•IRS
•Perifocal
insecticide
spraying
(tyres with
residual
insecticides)
•Topical
repellants,
protective
clothing,
household
insecticides

47. Vector control (Epidemic control)
Tools recommended Tools recommended at
certain settings
•Indoor space spraying using
pyrethrum
•Fogging or Ultra Low Volume
(ULV) spray using malathion
or cyphenothrin
•Intensified social
mobilisation campaigns
•Epidemic control legislation
•LLINs (for Dengue patients)
•IRS

48. Anti-Dengue month- July

49. India Fights Dengue App

50. Fight Dengue TN app
TN Toll-free no. 1800 425 1868

51. Advances in Dengue control
• One licensed vaccine-
CYD-TDV, Recombinant,
chimeric, tetravalent
dengue vaccine
• Use of Wolbachia
bacteria strains to infect
Ae. aegypti mosquitoes
• GM mosquitoes

52. WHO Global strategy for Dengue
prevention & control, 2012-2020
• To reduce the burden of Dengue
• To reduce mortality from Dengue by 2020 by
atleast 50% (using 2010 as baseline)
• To reduce morbidity from Dengue by 2020 by
atleast 25% (using 2010 as baseline)

53. Dengue fever can be easily
prevented
IT IS A COLLECTIVE
RESPONSIBILITY

54. Three-pronged strategy
Prevention
& Control
of Dengue
Disease
management
IVM
Supportive
interventions
Early diagnosis & tt.
Referral services
Epidemic preparedness
Rapid response
Environmental
Biological
Chemical
BCC, PPP, ISC, HRD, OR,
M&E, GIS

55. Integrated Vector Management

56. References
• GOI, MOHFW, Operational manual for Integrated
Vector Management in India. March 2016.
• Pang T, Mak TK, Gubler DJ. Prevention and control of
dengue- the light at the end of the tunnel. Lancet
Infectious Diseases, 2017; 17:e79-87.
• Comprehensive Guidelines for Prevention & Control of
Dengue & DHF, SEARO, WHO, 2011.
• WHO, Dengue control.
• www.nvbdcp.gov.in
Government of India (2006), National Vector Borne
Disease Control Programme. MOHFW, New Delhi

59. • Abolish or control larval habitats
• Modify human behaviour
• Create awareness
• Be prepared: Early diagnosis & prompt
management
• Notification of cases

60. Thank you….