Module 1 - Understanding Dengue Vector and Its Management by Dr. Waseem Akram

7/31/2019 Module 1 - Understanding Dengue Vector and Its Management by Dr. Waseem Akram

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UNDERSTANDING DENGUEVECTOR AND ITS MANAGEMENT

Prof. Dr. Waseem Akram, Head Research andDevelopment Program on Dengue Punjab,

Chief Ministers Secretariat


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Synopsis of Module 1

Insects of Public Health Concern

in Institutions

Vector borne disease

Understanding the Dengue

mosquito and generalmosquitoes

Mosquito breeding places


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INSECTS OF PUBLIC HEALTH

CONCERN IN INSTITUTIONS FLIES MOSQUITOES

BED BUGS

COCKROACHES

FLEAS

DERMESTID BEETLES

LOUSE

SANDFLIES

ROVE BEETLES


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VECTOR BORNE DISEASE YELLOW FEVER

MALARIA

FILARIASIS

JAPANESE ENCEPHALITIS

DENGUE

ASTHAMA

LESHMINIASIS

SKIN ALLERGIES

THYPHOID


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INSECTS OF PUBLIC HEALTH

CONCERN IN INSTITUTIONS


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MOSQUITOES AND THEIR ROLE

Mosquito-borne diseasescause significant humanhealth problems, largely in thesubtropics and tropics

WHO reports three mosquito-borne diseases around theworld:

500 million cases ofmalaria with2.7 million deaths, mainly inchildren.

Lymphatic filariasis with 120million people effected everyyear.

Dengue fever virus, particularlyits hemorrhagic form, is a threat

to >2.5 billion people.


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SOME OF THE VECTOR BORNE

INFECTIONS


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Since the 1960's, dengue has re-emerged throughout the world. Some notable outbreaks in the last two decades:

- 1977, Cuba: mild epidemic of dengue-1.

- 1977, Seychelles (Africa) - first major epidemic

- 1979, Laredo, Texas: two residents developed hemorrhagic fever.

- 1981, Havana, Cuba: A new strain of dengue-2 from Southeast Asia causes its first major epidemic: 350,000

infected; 115,000 hospitalizations; 156 dead.

- 1982, New Delhi, India: 20% of the 5.6 million residents fall ill to dengue-2

- 1982, Keyna - first major epidemic of dengue-2

- 1982-1984, Somalia - dengue-2

- 1985 - Mozambique, first major epidemic (dengue-3)

- 1985-1986, Nicaragua: indigenous population of Managuans

- 1985, Hainan Island, China - first major epidemic of dengue-2

- 1988, U.S.: 124 suspected cases of imported dengue, of which 27 (in 7 states) were definite, and 25 were

uncertain.

- 1990, Venezuela

- 1991, Brazil: epidemic, indigenous population.- 1991-1992, Djibouti (Africa) - first major epidemic

- 1993, Somalia: U.S. troops.

- 1994, Pakistan, first epidemic

- 1994, Nicaragua: dengue-3 reappears (a new strain genetically distinct from previous dengue-3 strains in the

Americas) and causes an epidemic of dengue hemorrhagic fever.

- 1994, Saudi Arabia, first major epidemic of dengue-2

DENGUE SITUATION AT AN ALARMING TONE


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History of Dengue in Pakistan First reported in 1980 and then showed regular turn

outs from 1994 to 1998

Pakistan faced the worst ever reported dengue

epidemic in the world

0.6million suspected cases,

22000 confirmed

375 deaths in a span of 73 days during the year 2011.

10

Year 2006 2007 2008 2009 2010

Cases in

Punjab

S C D S C D S C D S C D S C D

756 448 0 320 288 0 1248 1148 5 170 115 2 7835 6195 4


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Known Vectors

DF and DHF are caused

Aedes aegyptiandAedes

albopictus

These have extended their ranges fromAsian region to other continents

through trade and transportation.

Both the species have the

capacity to vector

Four serotypes (DEN1, DEN2, DEN3 andDEN4)

Transfer the virus to the people after

extrinsic incubation period of 4-6 days

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How has the disease spread

Climatic changes

Unplanned urbanization

Growing environmental

concerns Have led to the expansion

of vectors ranges andfinally the prevalence of thedisease.

Places which have shownsever epidemics haveopened doors to othervector borne issues.

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Ecological Determinants affecting

dengue incidence

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Factors Contributing to the Emergence

of Dengue Fever No effective mosquito control efforts are underway in most countries

with Dengue.

Public health systems to detect and control epidemics are deteriorating

around the world.

Rapid growth of cities has led to overcrowding, urban decay, andsubstandard sanitation, allowing more mosquitoes to live closer to morepeople.

The increase in non-biodegradable plastic packaging and discarded tiresis creating new breeding sites for mosquitoes.

Increased jet air travel is helping people infected with Dengue viruses tomove easily from city to city.


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Aedes

Lands with the head and tip of abdomen

pointing towards the surface

Culex

Anopheles

MalariaLands vertically on the surface

Lands with the head and tip of

abdomen pointing towards the

surface

Dengue Mosquito

and UsualMosquitoes


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Anopheles

Eggs laid singly on the surfaceof water

Eggs laid on raft which has many

eggs that floats on the surface ofwater

Eggs like rice grains very small in size

Laid singly on dry/wet/ or moist

vegetation/ sides of containers or on

the surface of water

Aedes

Culex

Eggs of different Mosquitoes


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Larval Stage of Anopheles

Mosquito

Anopheles spp.

Larva without siphon tube

Rests horizontal with the surface ofwater

Siphon tube ABSENT
http://www.arbovirus.health.nsw.gov.au/areas/arbovirus/mosquit/photos/anopheles_annulipes_larvae.jpg


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Larva of Culex Mosquito

Larva with long thinsiphon tube used forrespiration

Position of larvadependent upon thedepth of water it mayswim vertically

upward or slightlytilted


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Larva of Aedes mosquito

Larva withshort andthick siphon(Respiratorytube)

Moves inwater eithervertically orslightly tilteddepending

upon thedepth ofwater


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Larval Stages of Different Genera of Mosquito

Siphon and its size

Siphon and its size

Siphon absent


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PUPAE OF DIFFERENT GENERA OF MOSQUITOES

Culexspp.

Anopheles spp.

Aedes

Head capsule large

Rest of the body firmly

attached with head capsule Head capsule slightly

smaller than anopheles

Rest of the body partly

away from head capsule

Head small

Rest of the bodydistinctly away from

head capsule
http://www.arbovirus.health.nsw.gov.au/areas/arbovirus/mosquit/photos/culex_annulirostris_pupa.jpg


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MORPHOLOGICAL DIFFERENCES BETWEEN

SEXES

Female Pilose antennaMale Plumose antenna


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Morphological Appearances

Aedes albopictus Aedes aegypti


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TWO WITH A SINGLE MISSION


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Adults ofalbopictus and aegypti


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Adults ofalbopictus and aegypti


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Larvae ofalbopictus and aegypti


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Pupae ofalbopictus and aegypti


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Mosquito breeding places


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This is what we Generally Understand


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What and where do mosquitoes feed

upon

What do they feed

upon

Where do they feed

upon

Mosquitoes

feed upon blood

Anthropophagic

EndophagicExophagic

Endophilic

Exophilic

DIURNAL NOCTURAL


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IS IT CLEAR WATER?

Are tree wholes active

breeding places?

Is small quanity water

enough?

Is blood the only food?

female

Is blood the only food?

male

MOSQUITO BREEDING PLACES


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Behavior Pattern of various Mosquito types

Culexswarms

mostly large and

commonly found

Anopheles swarms large

and commonly found near

water collecting places and

the near sewerage pipes

Aedes swarms very

few and mostly inthe concealed

environment


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Disease Transmission Cycle

Environment

PathogenVector


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Transmission of Dengue Virus


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Replication and Transmission of DengueVirus (Part1)

1. Virus transmitted to

human in mosquito saliva

2. Virus replicates in

target organs3. Virus infects white

blood cells and lymphatictissues

4. Virus released and

circulates in blood


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Replication and Transmission of DengueVirus (Part2)

5.Second mosquito

ingests virus with

blood6.Virus replicates in

mosquito midgut andother organs,infects

salivary glands7.Virus replicates in

salivary glands


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Dengue Infected Patient


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Module 1 - Understanding Dengue Vector and Its Management by Dr. Waseem Akram

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