25/04/2017
WORLD MALARIA DAY
25 April 2017
World Malaria Day is an occasion to highlight the
need for continued investment and sustained
political commitment for malaria prevention and
control.
A push for prevention
This year’s global theme for World Malaria Day
is END MALARIA FOR GOOD.
WHO is shining a spotlight on prevention, a
critical strategy for reducing the toll of a
disease that continues to kill more than 400 000
people annually.
Fact sheet
Updated April 2017
Key facts
Malaria is a life-threatening disease caused
by parasites that are transmitted to people
through the bites of infected female
Anopheles mosquitoes.
In 2015, 91 countries and areas had ongoing
malaria transmission.
Malaria is preventable and curable, and
increased efforts are dramatically reducing
the malaria burden in many places.
Between 2010 and 2015, malaria incidence
among populations at risk (the rate of new
cases) fell by 21% globally. In that same
period, malaria mortality rates among
populations at risk fell by 29% globally among
all age groups, and by 35% among children
under 5.
The WHO African Region carries a
disproportionately high share of the global
malaria burden. In 2015, the region was home
to 90% of malaria cases and 92% of malaria
deaths.
Malaria is caused by Plasmodium parasites. The
parasites are spread to people through the bites
of infected female Anopheles mosquitoes, called
"malaria vectors." There are 5 parasite species
that cause malaria in humans, and 2 of these
species – P. falciparum and P. vivax – pose the
greatest threat.
P. falciparum is the most prevalent malaria
parasite on the African continent. It is
responsible for most malaria-related deaths
globally.
P. vivax is the dominant malaria parasite in
most countries outside of sub-Saharan Africa.
Symptoms
Malaria is an acute febrile illness. In a non-
immune individual, symptoms usually appear 10–
15 days after the infective mosquito bite. The
first symptoms – fever, headache, and chills–
may be mild and difficult to recognize as
malaria. If not treated within 24 hours, P.
falciparum malaria can progress to severe
illness, often leading to death.
Children with severe malaria frequently develop
one or more of the following symptoms: severe
anaemia, respiratory distress in relation to
metabolic acidosis, or cerebral malaria. In adults,
multi-organ involvement is also frequent. In
malaria endemic areas, people may develop
partial immunity, allowing asymptomatic
infections to occur.
Who is at risk?
In 2015, nearly half of the world's population
was at risk of malaria. Most malaria cases and
deaths occur in sub-Saharan Africa. However,
South-East Asia, Latin America and the Middle
East are also at risk. In 2015, 91 countries and
areas had ongoing malaria transmission.
Some population groups are at considerably
higher risk of contracting malaria, and
developing severe disease, than others. These
include infants, children under 5 years of age,
pregnant women and patients with HIV/AIDS, as
well as non-immune migrants, mobile populations
and travellers. National malaria control
programmes need to take special measures to
protect these population groups from malaria
infection, taking into consideration their specific
circumstances.
Disease burden
According to the latest WHO estimates, released
in December 2016, there were 212 million cases
of malaria in 2015 and 429 000 deaths.
Between 2010 and 2015, malaria incidence among
populations at risk fell by 21% globally; during
the same period, malaria mortality rates among
populations at risk decreased by 29%. An
estimated 6.8 million malaria deaths have been
averted globally since 2001.
The WHO African Region continues to carry a
disproportionately high share of the global
malaria burden. In 2015, the region was home to
90% of malaria cases and 92% of malaria
deaths. Some 13 countries – mainly in sub-
Saharan Africa – account for 76% of malaria
cases and 75% deaths globally.
In areas with high transmission of malaria,
children under 5 are particularly susceptible to
infection, illness and death; more than two
thirds (70%) of all malaria deaths occur in this
age group. Between 2010 and 2015, the under-5
malaria death rate fell by 29% globally.
However malaria remains a major killer of
children under five years old, taking the life of
a child every two minutes.
Transmission
In most cases, malaria is transmitted through
the bites of female Anopheles mosquitoes. There
are more than 400 different species of
Anopheles mosquito; around 30 are malaria
vectors of major importance. All of the
important vector species bite between dusk and
dawn. The intensity of transmission depends on
factors related to the parasite, the vector, the
human host, and the environment.
Anopheles mosquitoes lay their eggs in water,
which hatch into larvae, eventually emerging as
adult mosquitoes. The female mosquitoes seek a
blood meal to nurture their eggs. Each species
of Anopheles mosquito has its own preferred
aquatic habitat; for example, some prefer small,
shallow collections of fresh water, such as
puddles and hoof prints, which are abundant
during the rainy season in tropical countries.
Transmission is more intense in places where the
mosquito lifespan is longer (so that the parasite
has time to complete its development inside the
mosquito) and where it prefers to bite humans
rather than other animals. The long lifespan and
strong human-biting habit of the African vector
species is the main reason why nearly 90% of
the world's malaria cases are in Africa.
Transmission also depends on climatic conditions
that may affect the number and survival of
mosquitoes, such as rainfall patterns,
temperature and humidity. In many places,
transmission is seasonal, with the peak during
and just after the rainy season. Malaria
epidemics can occur when climate and other
conditions suddenly favour transmission in areas
where people have little or no immunity to
malaria. They can also occur when people with
low immunity move into areas with intense
malaria transmission, for instance to find work,
or as refugees.
Human immunity is another important factor,
especially among adults in areas of moderate or
intense transmission conditions. Partial immunity
is developed over years of exposure, and while it
never provides complete protection, it does
reduce the risk that malaria infection will cause
severe disease. For this reason, most malaria
deaths in Africa occur in young children,
whereas in areas with less transmission and low
immunity, all age groups are at risk.
Prevention
Vector control is the main way to prevent and
reduce malaria transmission. If coverage of
vector control interventions within a specific
area is high enough, then a measure of
protection will be conferred across the
community.
WHO recommends protection for all people at
risk of malaria with effective malaria vector
control. Two forms of vector control –
insecticide-treated mosquito nets and indoor
residual spraying – are effective in a wide
range of circumstances.
Insecticide-treated mosquito nets
Long-lasting insecticidal nets (LLINs) are the
preferred form of insecticide-treated mosquito
nets (ITNs) for public health programmes. In
most settings, WHO recommends LLIN coverage
for all people at risk of malaria. The most cost-
effective way to achieve this is by providing
LLINs free of charge, to ensure equal access
for all. In parallel, effective behaviour change
communication strategies are required to ensure
that all people at risk of malaria sleep under a
LLIN every night, and that the net is properly
maintained.
Indoor spraying with residual insecticides
Indoor residual spraying (IRS) with insecticides
is a powerful way to rapidly reduce malaria
transmission. Its potential is realized when at
least 80% of houses in targeted areas are
sprayed. Indoor spraying is effective for 3–6
months, depending on the insecticide formulation
used and the type of surface on which it is
sprayed. In some settings, multiple spray rounds
are needed to protect the population for the
entire malaria season.
Antimalarial drugs
Antimalarial medicines can also be used to
prevent malaria. For travellers, malaria can be
prevented through chemoprophylaxis, which
suppresses the blood stage of malaria infections,
thereby preventing malaria disease. For
pregnant women living in moderate-to-high
transmission areas, WHO recommends
intermittent preventive treatment with
sulfadoxine-pyrimethamine, at each scheduled
antenatal visit after the first trimester.
Similarly, for infants living in high-transmission
areas of Africa, 3 doses of intermittent
preventive treatment with sulfadoxine-
pyrimethamine are recommended, delivered
alongside routine vaccinations.
In 2012, WHO recommended Seasonal Malaria
Chemoprevention as an additional malaria
prevention strategy for areas of the Sahel sub-
region of Africa. The strategy involves the
administration of monthly courses of
amodiaquine plus sulfadoxine-pyrimethamine to
all children under 5 years of age during the
high transmission season.
Insecticide resistance
Much of the success in controlling malaria is due
to vector control. Vector control is highly
dependent on the use of pyrethroids, which are
the only class of insecticides currently
recommended for ITNs or LLINs.
In recent years, mosquito resistance to
pyrethroids has emerged in many countries. In
some areas, resistance to all 4 classes of
insecticides used for public health has been
detected. Fortunately, this resistance has only
rarely been associated with decreased efficacy
of LLINs, which continue to provide a substantial
level of protection in most settings. Rotational
use of different classes of insecticides for IRS
is recommended as one approach to manage
insecticide resistance.
However, malaria-endemic areas of sub-Saharan
Africa and India are causing significant concern
due to high levels of malaria transmission and
widespread reports of insecticide resistance. The
use of 2 different insecticides in a mosquito net
offers an opportunity to mitigate the risk of
the development and spread of insecticide
resistance; developing these new nets is a
priority. Several promising products for both IRS
and nets are in the pipeline.
Detection of insecticide resistance should be an
essential component of all national malaria
control efforts to ensure that the most
effective vector control methods are being
used. The choice of insecticide for IRS should
always be informed by recent, local data on the
susceptibility of target vectors.
To ensure a timely and coordinated global
response to the threat of insecticide resistance,
WHO worked with a wide range of stakeholders
to develop the " Global Plan for Insecticide
Resistance Management in Malaria Vectors
(GPIRM) ", which was released in May 2012.
Diagnosis and treatment
Early diagnosis and treatment of malaria
reduces disease and prevents deaths. It also
contributes to reducing malaria transmission.
The best available treatment, particularly for P.
falciparum malaria, is artemisinin-based
combination therapy (ACT).
WHO recommends that all cases of suspected
malaria be confirmed using parasite-based
diagnostic testing (either microscopy or rapid
diagnostic test) before administering
treatment. Results of parasitological
confirmation can be available in 30 minutes or
less. Treatment, solely on the basis of symptoms
should only be considered when a parasitological
diagnosis is not possible. More detailed
recommendations are available in the "WHO
Guidelines for the treatment of malaria" , third
edition, published in April 2015.
Antimalarial drug resistance
Resistance to antimalarial medicines is a
recurring problem. Resistance of P. falciparum
to previous generations of medicines, such as
chloroquine and sulfadoxine-pyrimethamine (SP),
became widespread in the 1950s and 1960s,
undermining malaria control efforts and
reversing gains in child survival.
WHO recommends the routine monitoring of
antimalarial drug resistance, and supports
countries to strengthen their efforts in this
important area of work.
An ACT contains both the drug artemisinin and a
partner drug. In recent years, parasite
resistance to artemisinin has been detected in 5
countries of the Greater Mekong subregion:
Cambodia, Lao People’s Democratic Republic,
Myanmar, Thailand and Viet Nam. Studies have
confirmed that artemisinin resistance has
emerged independently in many areas of this
subregion.
In 2013, WHO launched the Emergency response
to artemisinin resistance (ERAR) in the Greater
Mekong Subregion, a high-level plan of attack to
contain the spread of drug-resistant parasites
and to provide life-saving tools for all
populations at risk of malaria. But even as this
work was under way, additional pockets of
resistance emerged independently in new
geographic areas of the subregion. In parallel,
there were reports of increased resistance to
ACT partner drugs in some settings. A new
approach was needed to keep pace with the
changing malaria landscape.
Consequently, WHO’s Malaria Policy Advisory
Committee in September 2014 recommended
adopting the goal of eliminating P. falciparum
malaria in this subregion by 2030. WHO launched
the Strategy for Malaria Elimination in the
Greater Mekong Subregion (2015–2030) at the
World Health Assembly in May 2015, which was
endorsed by all the countries in the subregion.
With technical guidance from WHO, all GMS
countries have developed national malaria
elimination plans. Together with partners, WHO
will provide ongoing support for country
elimination efforts through a new malaria
elimination initiative that will replace the
former ERAR hub.
Surveillance
Surveillance entails tracking of the disease and
programmatic responses, and taking action based
on the data received. Currently many countries
with a high burden of malaria have weak
surveillance systems and are not in a position to
assess disease distribution and trends, making it
difficult to optimize responses and respond to
outbreaks.
Effective surveillance is required at all points
on the path to malaria elimination and the
Global Technical Strategy for Malaria 2016-2030
(GTS) recommends that countries transform
surveillance into a core intervention. Strong
malaria surveillance enables programmes to
optimize their operations, by empowering
programmes to:
advocate for investment from domestic and
international sources, commensurate with the
malaria disease burden in a country or
subnational area;
allocate resources to populations most in need
and to interventions that are most effective,
in order to achieve the greatest possible public
health impact;
assess regularly whether plans are progressing
as expected or whether adjustments in the
scale or combination of interventions are
required;
account for the impact of funding received
and enable the public, their elected
representatives and donors to determine if
they are obtaining value for money; and
evaluate whether programme objectives have
been met and learn what works so that more
efficient and effective programmes can be
designed.
Stronger malaria surveillance systems are
urgently needed to enable a timely and
effective malaria response in endemic regions,
to prevent outbreaks and resurgences, to track
progress, and to hold governments and the
global malaria community accountable.
Elimination
Malaria elimination is defined as the
interruption of local transmission of a specified
malaria parasite species in a defined
geographical area as a result of deliberate
activities. Continued measures are required to
prevent re-establishment of transmission. (The
certification of malaria elimination in a country
will require that local transmission is interrupted
for all human malaria parasites.)
Malaria eradication is defined as the permanent
reduction to zero of the worldwide incidence of
malaria infection caused by human malaria
parasites as a result of deliberate activities.
Interventions are no longer required once
eradication has been achieved.
The rate of progress in a particular country will
depend on the strength of its national health
system, the level of investment in malaria
control, and a number of other factors,
including: biological determinants, the
environment, and the social, demographic,
political, and economic realities of a particular
country.
In countries with high or moderate rates of
malaria transmission, national malaria control
programmes aim to maximize the reduction of
malaria cases and deaths.
As countries approach elimination, enhanced
surveillance systems can help ensure that every
infection is detected, treated and reported to a
national malaria registry. Patients diagnosed
with malaria should be treated promptly with
effective antimalarial medicines for their own
health and to prevent onward transmission of
the disease in the community.
Countries that have achieved at least 3
consecutive years of 0 local cases of malaria are
eligible to apply for the WHO certification of
malaria elimination. In recent years, 7 countries
have been certified by the WHO Director-
General as having eliminated malaria: United
Arab Emirates (2007), Morocco (2010),
Turkmenistan (2010), Armenia (2011), Maldives
(2015), Sri Lanka (2016) and Kyrgyzstan (2016).
The WHO Framework for Malaria Elimination
(2017) provides a detailed set of tools and
strategies for achieving and maintaining
elimination.
Vaccines against malaria
RTS,S/AS01 (RTS,S) – also known as Mosquirix –
is an injectable vaccine that provides partial
protection against malaria in young children. The
vaccine is being evaluated in sub-Saharan Africa
as a complementary malaria control tool that
potentially could be added to (and not replace)
the core package of WHO-recommended
preventive, diagnostic and treatment measures.
In July 2015, the vaccine received a positive
opinion by the European Medicines Agency, a
stringent medicines regulatory authority. In
October 2015, two WHO advisory groups
recommended pilot implementation of RTS, S/
AS01 in a limited number of African countries.
WHO adopted these recommendations and is
strongly supportive of the need to proceed with
the pilot programme as the next step for the
world’s first malaria vaccine.
In November 2016, WHO announced that the
RTS,S vaccine would be rolled out in pilot
projects in 3 countries in sub-Saharan Africa.
Funding is now secured for the initial phase of
the programme and vaccinations are due to
begin in 2018. These pilot projects could pave
the way for wider deployment of the vaccine if
safety and effectiveness are considered
acceptable.
WHO response
The WHO Global Technical Strategy for Malaria
2016-2030 – adopted by the World Health
Assembly in May 2015 – provides a technical
framework for all malaria-endemic countries. It
is intended to guide and support regional and
country programmes as they work towards
malaria control and elimination.
The Strategy sets ambitious but achievable
global targets, including:
Reducing malaria case incidence by at least
90% by 2030.
Reducing malaria mortality rates by at least
90% by 2030.
Eliminating malaria in at least 35 countries by
2030.
Preventing a resurgence of malaria in all
countries that are malaria-free.
This Strategy was the result of an extensive
consultative process that spanned 2 years and
involved the participation of more than 400
technical experts from 70 Member States. It is
based on 3 key pillars:
1. ensuring universal access to malaria
prevention, diagnosis and treatment;
2. accelerating efforts towards elimination and
attainment of malaria-free status; and
3. transforming malaria surveillance into a core
intervention.
The WHO Global Malaria Programme (GMP)
coordinates WHO's global efforts to control and
eliminate malaria by:
setting, communicating and promoting the
adoption of evidence-based norms, standards,
policies, technical strategies, and guidelines;
keeping independent score of global progress;
developing approaches for capacity building,
systems strengthening, and surveillance; and
identifying threats to malaria control and
elimination as well as new areas for action.
GMP is supported and advised by the Malaria
Policy Advisory Committee (MPAC), a group of
15 global malaria experts appointed following an
open nomination process. The MPAC, which meets
twice yearly, provides independent advice to
WHO to develop policy recommendations for the
control and elimination of malaria. The mandate
of MPAC is to provide strategic advice and
technical input, and extends to all aspects of
malaria control and elimination, as part of a
transparent, responsive and credible policy
setting process.
