Md. Kabiul Akhter AliVBD Consultant, PH Wing

World Health Day is celebrated

on 7 April every year to mark the

anniversary of the founding of

WHO in 1948 We are all one on

“WORLD HEALTH DA Y”

Each year a theme is selected that

highlights a priority area of public

health.

MD. K. A. ALI

Vector-borne disease (VBD): an illness caused by aninfectious microorganism (pathogen) that is transmitted topeople by a vector, usually arthropods

Arthropod: an invertebrate animal having an exoskeleton(e.g. insects or arachnids)

Definitions

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Common Vector Borne Diseases (VBD-s)

Dengue

Chikungunya

Yellow fever

Malaria

Japanese encephalitis

Kala-azar

Lymphatic filariasis

Scrub typhus

Plague

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Impact of Vector Borne Diseases

Causes High Burden….

Illness

Death

Worsening of poverty

Negative impact on economy

High health cost

Overloading of Health System

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VBD problem : global magnitude

50% population is at risk from Vector Borne Disease.

17% of infectious diseases due to VBDs.

40% population is at risk from Dengue.

1.3 Million new cases of Kala azar every year

Kill one million people every year out of which 660,000 die due to Malaria.

Dengue has increased 30 folds during last 50 years

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Types of VBD transmission

Vector VectorVector Vector

Humans

HumansAnimals

HumansAnimals

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Vectors spread diseases

Mosquitoes, flies, ticks, bugsand freshwater snails canspread diseases that causeserious illness and death

50% of world population

is at risk

Increased travel, trade andmigration make even morepeople vulnerable

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VBD & climate change

A.Temperature

B. Precipitation

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TemperatureExample– Summer: more days with higher temperature

effects

•

•

•

LongerLonger

Longer

lifespanreproduction period

activity period

– Winter: less days with low

temperature• Benefits overwintering

• Shorter overwinteringDr.T.V.Rao MD

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Temperature effectsPathogen

Decreased extrinsic incubation period of pathogen in vector at higher temperature

Changes in the transmission season

Changes in geographical distribution

Decreased viral replication

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Precipitation effectsVector•Survival: increased rain may increase larval habitat

•Excess rain can eliminate habitat by flooding

•Low rainfall can create habitat as rivers dry into pools (dry season mosquitoes)

•Decreased rain can increase container-breeding mosquitoes by forcing increased water storage

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Precipitation effectsVector

Heavy rainfall events can synchronize vector host-seeking and virus transmission

Increased humidity increases vector survival and vice-versa

PathogenFew direct effects but some data on humidity effects on parasite development

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Summary effects climate change

Climate change has the potential to

•Increase range or abundance of animal reservoirs and/or arthropod vectors

•Enhance transmission

•Increase importation of vectors or pathogens

•Every Human at Risk

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Diseases are Preventable

Malaria, dengue,leishmaniasis, JE andfilariasis arepreventable, yet theyhave the biggestimpact on some of theworld’s poorest people.

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Treatment of VBD-sMalaria :

• The current protocol is to

- treat vivax cases with chloroquine for 3 days, and

primaquine for 14 days to prevent relapse;

- treat all falciparum cases with artemisinin combination

therapy (ACT) and primaquine single dose for gametocyte

clearance.

Kala-azar :

• First line regimen is miltefosine orally x 4 weeks (for VL) and x

12 weeks (for PKDL).

• Shorter regimen with miltefosine & inj paromomycin or inj

lyposomal amphotericin-B in pilot districts.

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Limitation of treatment

• No specific drug so far available for cure of

Dengue, JE or Chikungunya.

- Supportive care is the mainstay of treatment.

- In Dengue, there is risk of haemorrhage/shock,

particularly if a new serotype takes entry.

• Specific drug available for Malaria & Kala-azar,

but evolution of drug resistance is common.

- Even resistance to artemisinin has started.

• No effective vaccine as yet against Malaria or

Dengue.

So the vector issues should be

further highlighted.

The importance of vector control and reduction of man-

vector contact need to be impressed upon the public.

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Changes in the vector ecology

• With worldwide changes in the climate and environment of villages & cities, vector breeding is on the rise.

• Deforestation tilts the man-vector balance.

• Because of mutations, certain mosquito species are becoming more efficient as vectors.

• Mosquitoes are adapting their behaviour. - As example, we found aedes

breeding in spots well exposed to sunlight.

• Vectors developing resistance to insecticides.

The threat is big !

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Protect yourself

You can protect yourself

and your family by taking

simple measures that

include sleeping under a

bed net, wearing a long-

sleeved shirt and trousers

and using insect repellent.

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Keep the Environment Clean

and Save many Lives

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SAVE THE PLANET

SAVE FROM VECTOR BORN DISEASES

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Challenges in prevention & control –(1/2)

Though there is no dearth of technical knowledge, some of the

challenges are :

• Reaching health service to 100% population, both rural and urban.

• Making services affordable to the population.

• Quality assurance of health care, both in public and private systems – for

diagnostics as well as treatment.

• Adequate surveillance of disease, vectors and the determinants for

diseases.

• Involving people in vector control and bringing about behavioural change

to make this possible.

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Important components of Health system

to meet the challenge (1)• Finance

o Adequate budgetary allocation

o Control over drug & diagnostic kit pricing

o Health insurance

o Provision of reimbursement to private sector

• Health manpower (both public and private)

o Adequate in number

o Adequate skill through initial and periodic training

• Health facilities

o Geographical distribution

o PPP model for hard to reach areas

o Adequately equipped facilities

• Standardised diagnostic and treatment protocol

o Binding for both public and private settings

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Challenges in prevention & control –(2/2)

• Sustaining & managing the human resource of the programme.

• Problems with vector control :

- Non-availability of effective measures e.g. in JE.

- Difficulty of access in disturbed/ hard to reach areas.

• Changing social and environmental determinants to effectiveness of

standard intervention in some high risk population.

• Lack of inter-sectoral coordination and convergence of action.

• Rehabilitation of survivors following JE.

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More informationwww.climatetrap.eu

www.ecdc.eu

www.who.int/globalchange/en/

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Thank You

MD. K. A. ALI