Transcript Magnitude of Malaria

Epidemiology
of Malaria
BY:
Hamad Aldosari
Awn Alqarni
Khalid Alshahrani
Fahad Alotaibi
Abdullah Alenezi
OBJECTIVES:

Magnitude of Malaria; prevalence of the health problem
Globally and in KSA.

To describe the disease pattern and trends. (person, place
and time).

identify the risk factors and high risk groups.

Describe the process of communicable diseases
transmission (Agent, Reservoir, Mode of transmission).

Identify the main methods for prevention and control.

Recognize the specific programs for prevention and control
of Malaria in KSA.
Magnitude of malaria
The current and potential future impact of
climate change on malaria is of major
public health interest. The proposed effects
of rising global temperatures on the future
spread and intensification of the disease,
and on existing malaria morbidity and
mortality rates, substantively influence
global health policy.
Global Prevalence of Malaria
According to the latest estimates, released in December
2013, there were about 207 million cases of malaria in
2012 and an estimated 627 000 deaths.
Malaria mortality rates have fallen by 42% globally since
2000, and by 49% in the WHO African Region.
Most deaths occur among children living in Africa where a
child dies every minute from malaria. Malaria mortality rates
among children in Africa have been reduced by an
estimated 54% since 2000.
Estimated annual expenditure on malaria research and
treatment: US$84million / year.

Malaria kills more people than AIDS

Malaria kills in one year what AIDS kills in 15 years.

For every death due to HIV/AIDS there are about 50 deaths due to
malaria.

To add to the problem is there increasing drug resistance to the
established drug.

Continues to be most important cause of fever and morbidity in
the world.
Global Prevalence of Malaria
Global Prevalence of Malaria
Since 2000, a tremendous expansion in the financing and coverage
of malaria control programs has led to a wide-scale reduction
in malaria incidence and mortality.
Annual malaria mortality rates
per 100,000 population since
1900
World excluding sub-Saharan Africa
sub-Saharan Africa
250
200
150
100
50
0
1900
1930
1950
1970
1990
1997

The General Directorate of Statistics of the Ministry of Health has
revealed the results of a study that reported 1,941 cases of malaria
in Saudi Arabia 3 years ago. The vast majority of cases were
concentrated in the Jizan and Asir regions. Other affected cities
included Madina which had 145 cases, Makkah with 92 cases, and
Jeddah with 66 cases.

The vast majority of malaria cases, 98.5 percent, were reported in
people arriving from abroad, and the remaining 1.5 percent of
cases were locally transmitted. With just under 2,000 reports in the
year 2010, statistically the incidence of malaria in Saudi Arabia is
considered almost non-existent with an occurrence rate of 0.2
cases in every 100,000 individuals in the country.

The highest incidence of malaria reports occurred during the
months of January and February in the year 2010 in the
southwestern regions of the Kingdom. A decline in malaria
incidence was noticed starting from March, followed by an
increase again in October and November. That is a normal pattern
since these months coincide with the rainy season which
contributes to the spread of malaria in these regions(3).
Predicted thermal performance of malaria parasite
development within the mosquito in relation to the temperatures
experienced at each of four study locations in Kenya, Africa(2).
History of one or more episodes of
malaria by age:
History of one or more episodes of
malaria by gender and age bracket:
This map shows the estimated limits
of Plasmodium falciparum malaria
transmission.
• This classification arises because
either health system surveillance
data (annual case incidence)
reported zero cases for three
consecutive years.
• risk of unstable malaria
transmission. These areas are
those where local transmission
cannot be ruled out, but levels of
risk are extremely low, with annual
case incidence reported at less
than 1 per 10,000.
• stable malaria transmission. This is
a very broad classification of risk
including any regions where the
annual case incidence is likely to
exceed 1 per 10,000.
Areas shown in light pink are those at the lowest levels of risk, where
annually averaged infection prevalence in 2-10 year olds (PfPR2-10) is
likely to be lower than 5%. Areas shown in red are those at intermediate
risk, where PfPR2-10 is likely to be higher than 5% but less than 40%. Areas
shown in dark red are those at the highest levels of risk, wherePfPR2-10 is
likely to exceed 40%.
Risk factors for getting
malaria :

Living or traveling in a country or region where
malaria is present.

Traveling in an area where malaria is common
and:

Not taking medicine to prevent malaria before,
during, and after travel, or failing to take the
medicine correctly.

Being outdoors, especially in rural areas, between
dusk and dawn (nighttime), when the mosquitoes
that transmit malaria are most active.

Not taking steps to protect yourself from mosquito
bites.
People at increased risk of
serious disease include:

Young children and infants

Travelers coming from areas with no malaria

Pregnant women and their unborn children

Malaria is more severe in people who have had
their spleen removed (splenectomy).

Poverty, lack of knowledge, and little or no
access to health care also contribute to malaria
deaths worldwide.
overview
MALARIA IS A MOSQUITO-BORNE PARASITIC DISEASE CAUSED
BY GENUS PLASMODIUM,
AFFECTING OVER 100 COUNTRIES OF THE TROPICAL
AND SUBTROPICAL REGIONS OF THE WORLD
Causative Agent

Malaria is caused by species of Plasmodium.

The genus Plasmodium contains over 200 species


at least 11 species infect humans. Most important are:

Plasmodium falciparum

Plasmodium malariae

Plasmodium ovale

Plasmodium vivax

Plasmodium knowlesi
Plasmodium parasites are highly
specific with female Anopheles mosquitoes
Vector

Female mosquitos of genus Anopheles are
primary hosts and transmission vectors.

Over 100 can transmit human malaria

Only 30–40 commonly transmit parasites of the
genus Plasmodium

Anopheles gambiae is one of the best known
which transmits Plasmodium falciparum
Vector

Only female mosquitoes feed on blood while the
males feed on plant nectar and do not transmit
the disease.

The females of Anopheles genus prefer to feed at
night
Life Cycle & Pathogenesis
Life Cycle & Pathogenesis

Inside the vector (sexual reproduction):

Young female mosquitoes ingest the malaria parasite
by taking a blood meal from an infected human carrier

The ingested gametocytes will differentiate into male
and female gametes and then unite to form a zygote
(ookinete) in the mosquito’s gut

The resulting ookinete penetrates the gut lining to form
an oocyst in the gut wall

The oocyst ruptures to release sporozoites that migrate
in the mosquito’s body to the salivary glands and are
ready to infect new human hosts
Life Cycle & Pathogenesis

Inside humans:

Malaria develops via two phases:

Exoerythrocytic: involves infection of liver

Erythrocytic phase: involves infection of RBC
(erythrocytes)
Life Cycle & Pathogenesis

A mosquito infects a person by taking a blood meal.

First, sporozoites enter the bloodstream, and migrate to the liver.
They infect liver cells (hepatocytes), where they multiply into
merozoites, rupture the liver cells, and escape back into the
bloodstream.

Then, the merozoites infect red blood cells, where they develop
into ring forms, trophozoites and schizonts which in turn produce
further merozoites.

Sexual forms (gametocytes) are also produced, which, if taken up
by a mosquito, will infect the insect and continue the life cycle.
Clinical diagnosis

Clinical diagnosis is based on the patient's symptoms
and on physical findings at examination.

The first symptoms of malaria (most often fever, chills,
sweats, headaches, muscle pains, nausea and
vomiting) are often not specific and are also found in
other diseases (such as the "flu" and common viral
infections)

In severe malaria (caused by Plasmodium falciparum),
clinical findings (confusion, coma, neurologic focal
signs, severe anemia, respiratory difficulties) are more
striking and may increase the index of suspicion for
malaria.
Common methods for parasitological
diagnosis of malaria
The two methods common in use :
1: Light microscopy (Gold standard)
Parasite density
Species diagnosis
Monitoring response to treatment
2: Rapid diagnostic tests (RDTs)
detecting circulating malaria
antigens .
Rapid diagnostic tests (RDTs)
Malaria prevention and
control
Control and prevention
elements

The goal of the malaria control and elimination
program is interruption of malaria transmission and
this is can be done via

Malaria is prevalent in tropical and subtropical
regions because rainfall, warm temperatures, and
stagnant waters provide habitats ideal for
mosquito larvae.
Vector control

is the main way to reduce malaria transmission at
the community level. It is the only intervention that
can reduce malaria transmission from very high
levels to close to zero. For individuals, personal
protection against mosquito bites represents the
first line of defense for malaria prevention.
Types of vector control
1-Indoor spraying with residual insecticides:
spraying of insecticides on the walls inside a home. After feeding,
many mosquitoes rest on a nearby surface while digesting the
bloodmeal, so if the walls of houses have been coated with
insecticides, the resting mosquitoes can be killed before they can bite
another person and transfer the malaria parasite
2- mosquito nets
Bed nets are a sensible physical barrier precaution
against malaria-transmitting mosquitoes since the
major malaria vectors bite during the night
It contains many types:
1.
Traditional bed nets
2.
Insecticide-treated nets (ITNs)
3.
Long-lasting insecticidal nets (LLINs)
Long-Lasting Insecticidal Nets
(LLINs)

These are pretreated with insecticides.

They last about 3 to 5 years, and do not need to be retreated.

They are an effective and inexpensive way to prevent malaria.

They are recommended by the World Health Organization
Larval control

Some fish, such as mosquitofish, carps, and Tilapia, eat
mosquito larvae.

Dragonflies, and perhaps also birds, bats, and lizards also
kill larvae.

Larvae can also be killed by surface films or by some
chemicals such as methoprene that are toxic to
mosquitoes.

filling and draining or by increasing the speed of water in
natural or artificial channels.
Personal protection

When travelling in areas with malaria, wear loosefitting long trousers and long sleeves in the
evenings, as the mosquitoes that carry malaria
are most active at this time.
Health education

strategies promoting awareness of malaria and
the importance of control measures have been
successfully used to reduce the incidence of
malaria in some areas of the developing world.
Recognizing the disease in the early stages can
stop the disease from becoming fatal. Education
can also inform people to cover over areas of
stagnant, still water, such as water tanks that are
ideal breeding grounds for the parasite and
mosquito, thus cutting down the risk of the
Prevention

Methods used to prevent malaria include
medications, mosquito elimination and the
prevention of bites. There is no vaccine for
malaria.

Chloroquine-Doxycycline-Mefloquine-PrimaquineAtovaquone
Malaria control in KSA

n 1998, the Kingdom of Saudi Arabia (KSA)
suffered its worst malaria epidemic. A total of
36,139 locally transmitted cases were recorded
and incidence reached as high as 44/1000 in
malarious regions

hese activities had a significant impact, in 2011
only 29 locally transmitted cases were recorded in
the country, reducing incidence to <0.01/1000,
HOW ?

1- health education in endemic area

2- try to early diagnose and treat for malaria

3- establish central labs for diagnosing in endemic
area

4- use all the control and prevention methods of
WHO

1948 ARAMCO

1952 Cooperation between saudi government
and Who
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1970 no more cases in dammad and north saudi
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1978 asir and jizan - Cooperation with yemeni
government

1982 using insecticides in endemic areas
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1983 activation of all the methods of WHO