Vector Borne Diseases.pptx

MBBS.USMLE, DPH, Dip-Card, M.Phil, FCPS,PhD
Professor Community Medicine
Gujranwala Medical College Gujranwala.
Ex- Professor Community and Family
Medicine UmulQurrah University Makka
Saudi Arabia

1
10/11/2023 2/53
Prof Muhammad Tauseef Jawaid

Introduction to
vector-borne disease
(VBD)
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What is vector-borne disease?
Diseases that are spread by arthropod or
small animal vectors.
Vectors act as the main mode of
transmission of infection from one host to
another, & as such form an essential stage
in the transmission cycle.
10/11/2023 Prof Muhammad Tauseef Jawaid

Types of VBD transmission
5
Human-vector-human
(Anthroponotic Infections)
Vector
Humans
Humans
Vector
Examples:
Malaria
Dengue
Yellow fever
Animal-vector-human
(Zoonotic Infections)
Vector Vector
Animals
Animals
Humans
Examples:
Lyme disease
Hantaviral disease
Most arboviral diseases (e.g. WNV)

Vector-borne disease dynamics
Susceptibl
e
population
• Migration (forced)
• Vector environment
Vector
• Survival, lifespan
• Reproduction/breeding patterns
• Biting behavior
Pathogen
• Survival
• Transmission
• Replication in host
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Outline of Presentation
• Common Vector Borne Diseases in India
• Malaria
• Dengue
• Chikungunya
• Filaria
• Japanese Encephalitis Kala azar
• Prevention from the Vector Borne Diseases
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Common Vector Borne
Diseases in India
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Small Bite - Big Threat
• Malaria
• Dengue
• Chikungunya
Mosquito
• Filaria
• Japanese
Encephalitis
• Kala azar - Sandfly
Mosquito
Sandfly

Malaria
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Malaria
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• Mal’aria means “bad air”
(Originally thought to be caused by foul air)
• A life-threatening protozoan disease
• 40% of the world’s population is at risk of getting the disease
• 80% of population in India lives in low malaria endemic
region
• 80% of malaria burden in India is confined to 20% of
population that live in malaria endemic region in India

Trend of Malaria indices in
India, 2001-13
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Source - http://nvbdcp.gov.in/malaria3.html

Mosquito
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• Female anopheles mosquito is
the vector
o P. vivax
o P. Falciparum
• The mosquito breeds in polluted
water bodies, brackish water,
wells, cisterns, fountains,
overhead tanks etc.
• Mosquito bites during
night time

Transmission Cycle
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of humans
humans
healthy humans
Mosquito

Common Symptoms
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Symptoms:
o Fever (High grade)
Chills & rigors
o Headache
o Body ache
o Non specific symptoms

Severe Malaria - consequences
• Jaundice
• Seizure
• Bleeding problems
• Liver failure
• Kidney failure
• Multi organ failure
• “Death” also as a possible outcome
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Diagnosis
Rapid Diagnostic Kit Test Traditional slide test for parasite 10/53
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Treatment
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• Rest and fever control (Tab.Paracetamol)
• Cold Sponging
• Chloroquine for three days
• Plasmodium vivax – Primaquine for 14 days (in addition to
chloroquine)
• Plasmodium falciparum – Artesunate Based Combination therapy
• Severe malaria may require
o Artesunate based combination therapy
o Quinine
• Infants and pregnant women for giving special attention

“Require immediate attention”
with danger signs
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• Patient becomes unconscious
• Severe headache
• Seizures
• Bleeding from any site
• Development of jaundice
• Unable to pass urine

Facilities available at AIIMS
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• Management of malaria
and its complications
o Treatment of malaria
o Blood transfusion
• Diagnosis of Malaria and
its complications
o Kit test
Slide test
o Fluorescent microscopy
o PCR
• Available at:
o Dept of Microbiology
o Dept of Pathology
• Available at:
o Dept of Medicine/Pediatrics
o Blood bank

Dengue
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• Dengue fever is caused by Dengue virus
• It is pronounced as “Dengee”
• Occurs in epidemic form from time to time
• Common name of the disease is ‘break-bone fever’
(Haddi Tod Bukhar)
Dengue
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Reported Dengue Cases in Delhi,
2002 – 2013
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4000
5000
6000
7000
6259
5574
1000
2000
2882
3000
606
1023
3366
548
1312 1153 1131
2093
Numbers
45
0
2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013
No. of Dengue cases in Delhi Years
Source - http://nvbdcp.gov.in/malaria3.html

• Common disease in tropical
and subtropical countries
• Causative agent is a virus
The vector is mainly a
mosquito called Aedes
aegypti commonly known as
Tiger Mosquito
• Environment Helps
transmission
What is Dengue ?
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Know Your Enemy !!
Presence of black and white patches
over the legs (Tiger Mosquito)
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Environmental Factors
• Season: July – December
• Biting time mostly during day
• Ideal Temperature- 20-28
degree Celsius.
• Humidity - high
• Tiger mosquito breeds in fresh
water pools
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• All age groups & both sex are
vulnerable
• Those previously infected by
dengue are more likely to
experience severe form of
disease, if re-infected
Vulnerability to Dengue
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Infected mosquito
Transmission Cycle
Man-Mosquito-Man
Uninfected
human
Uninfected mosquito 22/53
Infected
human
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Symptoms
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• Fever
• Rash
• Headache
• Muscle pain
• Joint pain
• Pain behind the eyes

Dengue Hemorrhagic fever
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• Decrease in Platelet count
(a component of blood) leads
to bleeding
o Bleeding from gums
o Bleeding into joints
o Bleeding under the skin causing its
discolouration
o Petecheal hemorrhages
o In gut causing black colored stools or even
frank blood

Treatment
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• Fluids
• Rest
• No injections are required
• Paracetamol for pain and fever
• Monitor platelet count and
Blood pressure
• In severe cases, platelet
transfusion /blood transfusion

with danger signs
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•Bleeding from any site
•Severe abdominal pain
•Prolonged frequent vomiting
•Unconsciousness
•Raise in the temperature

Facilities Available at AIIMS
• Diagnosis
o Kit test
o Virus culture
o Reverse Transcriptase
Polymerase Chain Reaction
(RT-PCR) test
o Arterial Blood Gas (ABG)
analysis
• Available at:
o Dept of Microbiology
o Dept of Pathology
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• Treatment
o In-door admission
o IV infusion
o Blood transfusion
• Available at:
o Dept of Medicine/Pediatrics
o Blood bank

Japanese Encephalitis
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Japanese Encephalitis (JE)
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• JE is mostly present in in Southern India, Uttar
Pradesh, North Eastern states, Haryana
• Agent - Group B arbovirus (Flavivirus)
• Transmitted by Culex mosquitoes

Symptoms
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• Starts with
o Fever
o Headache
o Weakness
•High grade fever
•Neck pain
•Vomiting
•Seizure
•Inability to speak
•Paralysis
Rapidly progress to

Treatment
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• Consists of symptomatic management .
• May include
o Sponging for fever
o Paracetamol
o Drugs for Seizure
o Oxygen therapy
o Patient may need referral to higher level of health
care facility

Danger signs
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•Unconsciousness
•Seizure
•Poor respiration
•Paralysis

Chikunguny
a
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Epidemiology
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• Viral disease
• Transmitted by tiger mosquito (Aedes Aegyptus)
• Out break of chikungunya in India occurred in 2006,
affecting 14 lakh people

Symptoms
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• Fever
• Chills
• Headache
• Generalized body ache
• Skin rash
• Small joint pains

Treatment
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• Analgesics
o Paracetamol
o Diclofenac
• Plenty of fluid
• Avoid aspirin
• Normal food intake

Filari
a
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Epidemiology
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• Caused by : Microfilaria
• Transmitted by : Culex
mosquito
• Mainly prevalent in costal
areas due to hot and humid
conditions
Culex mosquito

Clinical features
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• Majority remains
asymptomatic
• Fever
• Swelling and pain in limbs
• Permanent disfigurement of
limbs
• Some people may develop
allergic reactions

Diagnosis &
Treatment
• DIAGNOSIS
o Blood examination for
microfilaria
o Antibody test
• TREATMENT
o Di-Ethyl Carbamazine
with Albendazole
o Ivermectin with
Albendazole
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with danger signs
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Generally filariasis do not lead to any life threatening
complication
Medication cause larval death in body which could
sometimes lead to allergic reactions like swelling of
body, itching etc.
Any reactions after taking medication should be reported
to the doctor

Kala-
Azar
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Epidemiology
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• Caused by parasite
Leishmania donovani
• Transmitted by sandfly
• The organism may remain in
the body for a long time in
liver, spleen and bone
• In India found in
Bihar, Jharkhand, West Bengal
and pockets of Uttar Pradesh

Clinical features
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• Intermittent fever
• Weakness
• Fullness of abdomen due
to increase in size of liver
and spleen
• Grey discoloration of skin
with loss of hair
• Decrease in hemoglobin

Management
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Diagnosis
• Blood test for antibody
• Dipstick test
• ELISA
• Biopsy
Management
• Sodium stibogluconate
• Pentamidine
• Amphotericin-B
• Miltefosine
• Available at:
• Dept of Microbiology
• Dept of Pathology
• Available at:
• Dept of Medicine/Pediatrics

Prevention from the Vector Borne Diseases
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• Don’t allow water to remain
stagnant in and around your
house.
• Clean the blocked drains.
1. Reducing the source
where the mosquito
can breed . . . 1
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• Empty - room air coolers and
flower vases completely at least
once in seven days and then refill
them
• Tray below the fridge also to be
cleaned

1. Reducing the source
where the mosquito
can breed . . . 2
•Dispose off old containers, tins, and
tyre etc.
•Keep the water tanks and water containers
tightly covered so that the mosquitoes can
not enter them and start breeding
•Fill the ditches
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• Introduction of some types
of small fish (Gambusia,
Lebister) which eat
mosquito larva into water
bodies
• Pouring oil over the water
sources
2.Killing the mosquito and
larvae . . . 1
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• Don’t turn away spray
workers whenever they
come to spray your house
• Spraying of
DDT, Malathion and
Pyrethrum etc.
• Spraying over all the walls
of the house
2. Killing the mosquito and
Larvae . . . 2
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• Don’t forget to spray
oBehind the photo-frames
oCurtains
oCalendars
oCorners of house
oStores
•Use insecticidal sprays in all
areas within the house at-
least once a week
2. Killing the mosquito and
Larvae . . . 3
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• Wear clothes which cover
the body as much as
possible
• Mosquito net
• Mosquito nets treated
with insecticides
• Mosquito repellent
o Sprays
o Creams
o Coils
o Mats
o Liquids
3. Personal protection
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Direct effects of climate
change on vector-borne
disease
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Temperature effects on vectors &
pathogens
Vector
• Survival decrease/increase depending on the
species
• Changes in the susceptibility of vectors to
some pathogens
• Changes in rate of vector population growth
• Changes in feeding rate & host contact
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Temperature effects on vectors &
pathogens
Pathogen
• Decreased extrinsic incubation period of pathogen in
vector at higher temperatures
• Changes in the transmission season
• Changes in geographical distribution
• Decreased viral replication
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Precipitation effects on vectors
Vector
• 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 malaria)
• Decreased rain can increase container-breeding
mosquitoes by forcing increased water storage
• Heavy rainfall events can synchronize vector
host-seeking & virus transmission
• Increased humidity increases vector
survival & vice-versa
Source: Gubler et al. (2022)
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Precipitation effects on pathogens
Pathogen
• Few direct effects but some data on humidity
effects on malarial parasite development
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• Increased relative humidity increases activity,
heavy rainfall decreases activity
• Increased activity increases transmission rates
Photo: National Geographic Photo: Ranger DJ
Vector activity
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Vector & host seasonality
• Vector-borne zoonoses mostly maintained by
wildlife
• Vectors & their hosts are subject to seasonal
variations that are climate related (e.g.
temperature) & climate independent (e.g.
day-length)
• Seasonal variations affect abundance &
demographic processes of both vectors &
hosts
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• Vector seasonality due to temperature affects
development & activity → transmission
• Host demographic processes (reproduction,
birth & mortality rates), affected directly by
weather & indirectly by resource availability →
VBD epidemiology
Vector & host seasonality
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Association between weather &
climate on VBDs
66
Source: IPCC (2013)
10/11/2023

Vector Borne Diseases
can be Easily Prevented!
It is
Your, Mine and …
Our RESPONSIBILITY
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Vector Borne Diseases.pptx

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Vector Borne Diseases.pptx