more than half the world's population at the risk of vector-borne diseases such
as malaria, dengue,
leishmaniasis and yellow fever, the World Health Organization (WHO) has chosen
the same as the theme for this year's World Health Day with the slogan, "Small
bite, big threat". April 7th is celebrated every year as the World
Health Day, and it marks the anniversary of the founding of WHO in 1948.
What are Vectors?
are organisms that carry diseases from person to person and from one place to
another. These include agents such as mosquitoes, flies, ticks and bugs. The
important diseases caused include malaria
leishmaniasis and yellow fever. These diseases impose heavy health and economic
burdens. The most important aspect of vector-borne diseases is that they are
The poorest people in the world remain as the
ones mostly affected with vector-borne diseases. Poor housing, unsafe water,
contaminated environment are factors that serve as breeding grounds for
Which are the
Important Vector-borne Diseases?
Malaria is the biggest killer among
vector-borne diseases. It kills an estimated 627 000 people every year. Sadly
most of the new cases, i.e. about 200 million ones every year, are never tested
Forty percent of the world's population is at
risk from dengue, another mosquito-borne viral infection. Early detection and
proper medical access can bring down its fatality rates below 1%. Mosquitoes
are also notorious for causing yellow fever that tend to erupt in large
outbreaks and paralyze health systems.
Repeated bites of infected blackflies of the
results in Onchocerciasis or "river
causes severe joint
pain; the term is from the Makonde language and means "that which
bends up". Japanese encephalitis is a fatal infection that can permanently
damage the central nervous system. Schistosomiasis is responsible for poor
nutritional status and poor school performance.
The bite of infected female phlebotomine sandfly causes Leishmaniasis
. The visceral form
of the disease kills over 20,000 deaths annually. Lymphatic filariasis is another widely rampant
ailment that affects around 120 million people currently. Chagas disease,
affects nearly 10 million people worldwide and damages the muscles of the heart
in the long run.
Is there a
is the single and most powerful weapon that can be used
against the killer disease. Sadly, it has never been used to its full
potential. The 1940s and 1950s saw the advent of insecticides whose massive
usage served a strong blow to the prevailing diseases. However, the impulse
never lasted. Control programmes lost their vigour; policy formulation lapses,
poor administration, and vanished infrastructure brought back the diseases.
Vectors gained resistance to the common insecticides.
One of the key messages for this year's World
Health Day is: "countries and their development partners must appreciate the
urgent need to act before an alarming situation deteriorates any further"
The available effective interventions include:
• Long lasting insecticide-treated bednets
- these are highly cost effective and
efficient. They offer protection against mosquito-borne
, particularly malaria. WHO recommends that these nets are
checked regularly for holes and replaced every 2-3 years.
• Indoor residual spraying with insecticides
-this is the most widely used method to control mosquitoes. It
is also effective against sandflies and bugs. Apt choice of insecticides
considering factors such as safety for humans and the environment can offer
protection for up to 12 months. However, at least 80 % of houses in a targeted
area need to be sprayed so that we get the maximum impact.
• Outdoor spraying-
Spraying outer surfaces of domestic animal
shelters, outdoor latrines and other damp places, aerial spraying of larvae
breeding sites are effective measures.
• Addition of certain approved insecticides
to drinking water storage containers is
effective against mosquito larvae, taking extreme measures that the doses are
not toxic for humans. Insect
in the form of coils, vaporizing mats, aerosols and
insecticide-impregnated curtains are also available.
Apart from the above mentioned steps WHO also
recommends: proper management of the environment so as to reduce breeding habitats,
biological control (for example, Larvivorous fish are effective in controlling
the larvae of Aedes mosquito), genetic control (the introduction of
genetically-engineering mosquitoes is a fine example), adequate waste
Timely medications, the introduction of effective
, ensuring blood and body
fluid safety, food safety add up to our ammunition.
can save millions and this calls out for a global
A global brief on vector-borne diseases- WHO