Vector Borne Diseases - PIB
The
tag line of this year's World Health Day 'Small Bite Big Threat', compel to turn
the attention towards the alarming occurrence of vector borne diseases, and it
substantiate and recommends
the governments, local authorities, community groups and individuals to work
together to prevent vector borne diseases. "Mosquitoes, flies, tick and bugs
may be a threat to your health-and that of your family-at home and when
travelling", is the message of this year's World Health Day.
Epidemiology
Vectors are organisms that transmit pathogens and parasites from one infected
person (or animal) to another. Vector borne diseases are illnesses caused by
these pathogens and parasites in human population and account for 17% of the
estimated global burden of all infectious diseases. Although, the disease most
commonly found in tropical areas where 40% of the population is at risk,
globalization, climate change and urbanisation have affected transmission of
vector borne diseases and causing their appearance in countries where they were
previously unknown.
Major
Vector Borne Diseases
Sl.No.
|
Name of the
Disease
|
Vector
|
Causative
agent
|
Certitude
|
1.
|
Dengue
|
Infected Female
Aedes aegypti Mosquito |
Virus
|
More than 2.5 billion
people-over 40% of words population-are now at risk of
dengue.
|
2.
|
Malaria
|
Infected female
Anopheles Mosquito |
Parasite
Plasmodium
|
Around the word,
Malaria transmission occurs in 97 countries, putting about 3.4 billion people at
risk
|
3.
|
Lymphatic filariasis
or Elephantiasis
|
Infected Mosquitos
Culex, Anopheles, Aedes |
Filarial
parasite
|
More than 120 million
currently infected and 40 million disfigured and
incapacitated
|
4.
|
Chikungunya
|
Infected female
Aedes aegypti Mosquito |
Virus
|
There is no specific
treatment for the disease. Treatment is symptomatic.
|
5.
|
Yellow
Fever
|
Infected Mosquito
Aedes and Haemagogus |
Virus
|
Vaccination is the
most important preventive measure against yellow fever. There is no specific
treatment
|
6.
|
Schistosomiasis
|
Infested water. Larva
of the Parasite released by fresh water snails.
|
Parasite
Trematode flat
worms
(Blood flukes)
|
Disease prevalent in
poor communities without safe drinking water and
sanitation.
|
7.
|
Chagas disease
(American Trypano somiasis)
|
Triatomine Bugs
(Kissing bugs) |
Protozoan
Parasite
Trypanosoma
Cruzi
|
Potentially Life
threatening condition. 7-8 million people infected worldwide, mostly in Latin
America. There is no vaccine
|
8.
|
Congo-Crimean
haemonhage fever
|
Tics and livestock
animals
|
Nairo
Virus
|
Case fatality rate up
to 40%. There is no vaccine available for either people or
animals.
|
9.
|
Human African
trypanosomiasis (Sleeping sickness)
|
Infected Tsetse
fly
|
Protozoan
Parasitc
|
Fatal without prompt
diagnosis and treatment
|
10.
|
Leishmaniasis
(Kala-azar)
|
Infected Female sand
flies
|
Protozoan
Leishmania
Parasites
|
Every year there are
1.3 million new cases and 20,000 to 30,000 deaths
|
11.
|
Lyme
|
Infected deer
ticks
|
Borrelia
Bacteria
|
It
is now the most common tick borne disease in northern
hemisphere
|
12.
|
Onchocerciasis
(River Blind
Blindness)
|
Infected black
flies
(Simulium
spp.)
|
Parasitic worm
onchocerca volvulus
|
In
2013 Colombia become the 1st country to be declared onchocerciasis free by
WHO
|
13.
|
Japanese
Encephalitis
|
Culex
mosquito
|
Virus
|
Vaccine is the most
preventive measure. There is no specific
treatment.
|
Prevention
and control
Time
has come to utilize the full potential for vector control for reducing
vector-borne disease. Back in 1940's, the discovery of synthetic insecticides
was a major breakthrough and the massive use of insecticides in 1940's and
1950's successfully brought many important vector-borne diseases under control.
But, with in the past two decades, many important vector-borne diseases have
re-emerged or spread to new parts of the world. Alongside this alarming spread
of vectors there is a serious concern of increasing insecticide resistance. At
the same time, the world is facing an extreme shortage of entomologists and
vector control experts who promote 'integrated vector management' as the best
approach to strengthen vector control. This approach uses a range of
interventions, from indoor residual spraying to the use of natural insect
predators, in combination and in a value added way. Integrated management makes
sense as many vector borne diseases overlap geographically.
Key
elements in the prevention and control of vector borne diseases include the
following:
· Long-lasting
insecticidal nets.
· Indoor
residual spraying
· Outdoor
spraying
· Addition
of chemicals to water
· Insect
repellents like coils, vaporizing mats.
· Reducing
breeding habit of the vector.
· Biological
control of vectors through the introduction of parasites, predators or other
living organisms.
· Genetic
control strategies.
· Waste
management.
· Housing
modification
· Personal
protection against the vector
· Medication
for travelers
· Prophylaxis
and preventive therapies.
· Mass
treatment for lymphatic filariasis, sotistosomiasis, onchocerciasrs.
· Vaccines
for Japanese encephalitis, Tick-borne encephalitis, and yellow fever.
· Blood
and body fluid safety in the case of Chagas disease and crimean-congo haemonhage
fever.
· Food
safety in case of Chagas disease and Tick borne encephalitis.
Key
challenges in the control of vector-borne diseases include.
Ø Emerging
insecticide resistance.
Ø Lack
of expertise in vector control.
Ø Surveillance
of vectors and their diseases.
Ø Sanitation
and access to safe drinking water.
Ø Pesticide
safety and poisoning
Ø Climate
and environmental change.
The poorest segment of of the society and least developed countries are most
affected by vector born diseases. illness and disability prevent people from
working and supporting themselves and their family causing further hardship and
impeding economic development.
World
Health Day is celebrated on 7 April every year to mark the anniversary of the
founding of WHO in 1948. Each year a theme is selected that high lights a
priority area of public health. The Day provides an opportunity for individuals
in every community to get involved in activities that can lead to better
health. In recent years, renewed commitments from ministries of health,
regional and global health initiatives, with the support of NGO's, the private
sector and the scientific community, have helped to lower the incidence and
death rates from some vector-borne diseases.
As vector borne diseases begin to spread beyond their traditional boundaries,
action needs to be expanded beyond the countries where these diseases currently
thrive. WHO resolved to provide communities with information and aims to raise
awareness about the threat posed by vectors and vector-borne disease, and to
stimulate families and communities to take action to protect themselves from the
perennial bane.
*Dhanya Sanal,
(Assistant Director, PIB)
Thiruvananthapuram
PIB
(Feature)
******
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