Principles of Communicable Diseases Epidemiology

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Infectious Diseases
CHP400 COMMUNITY HEALTH PROGRAM-II
Emerging and Re-emergingInfectious Diseases
Malaria Epidemiology Control
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Mohamed M. B. Alnoor
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Malaria
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• Importance of malaria
• Mode of Transmission
• Factors Influencing Transmission
• Stable and unstable malaria
• Control and prevention of malaria

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Malaria
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Importance
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• 1/2 world pop live in malarious areas
• 219 million infections(154 289 million),
• Kills a child every minute
• 660,00 deaths( mostly African children)
• 90 deaths in Africa(1/6 childhood deaths)
• Untreated P. falicparum lt 25
• Anaemia among children
• pregnancy anaemia low birth weight

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Malaria
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Importance
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• Serious economic impacts in Africa.
• A disease of poverty the poor in malaria-prone
  rural areas live in poorly-constructed dwellings
  offering no barriers against mosquitoes.

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• Malaria is both preventable and treatable,

• Resistance of parasite to drugs
• Resistance of mosquito to insecticdes

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Malaria
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Mode of Transmission
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Agent Plasmodium sp. P.
falciparum P. vivax P. ovale P.
malariae Vector Anopheline Reservoir Man
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Malaria
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Mode of Transmission
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Mosquito Man
Man
Mosquito
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1-3 yrs P. vivax 1 yr P.
falciparum
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Malaria
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Mode of Transmission
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Malaria
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Mode of Transmission
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Factors Influencing Transmission
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• Host factors
• Parasite factors
• The vector
• The environment

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Malaria
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Immunity
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Unstable malaria Low endemicity
spleen rate 50 Stable malaria High
endemicity spleen rate 50
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Malaria
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Immunity
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Unstable malaria All population
groups Stable malaria Newborn3-6/12(immune
mothers) childhood Clinical malaria
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• Intermittent absence of parasitaemia.
• Lower parasite density.
• Premunition.
• Splenomegaly.

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Malaria
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Immunity
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Stable malaria
Adolescents and adults Parasitaemia
sometimes Clinical symptoms
occasional Pregnant especially primigravidae
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Immunity
Use of prophylaxis
Delays the process of immunity
Serious disease on re-exposure
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Malaria
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Malaria
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Control (and Prevention)
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• Vector Reduction
• Vector-host contact reduction
• Parasite reduction
• Research

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Malaria
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Control (and Prevention)
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• Vector Reduction

• Breeding sites
• Destruction of larvae
• Adult anophelines

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Malaria
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Control (and Prevention)
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• Vector-host contact reduction

• Well screened areas.
• Mosquito nets (ITN).
• Cover most of the body.
• Use repellent on exposed skin.
• Insecticide spray.
• Antisporozoite vaccine?

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Malaria
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Control (and Prevention)
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• Parasite reduction

• Chemotherapy
• Chemoprophylaxis
• Antimerozoite vaccine?
• Antigamitocyte vaccine?

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• Research

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Malaria
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Control (and Prevention)
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(RBM)
Roll Back Malaria
WHO, UNICEF, UNDP and the World Bank,

• - ITN
• Treatment
• Anemia
• IPT

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IPTi 3,69- 59 IPTc IPTsc anemia IPTp twice
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Malaria
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Malaria
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Resurgence
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The problem is increasing Vector Breeding
site Cost and resistance Changing
habits Parasite Resistance and cost
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Malaria
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Resurgence
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Chloroquine 16 years
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1940
1950
1960
1970
1980
1990
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Malaria
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Resurgence
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• Population
• Movement.
• In-cooperation.
• Neighboring countries
• Inadequate Control
• Political and economic.
• Technical.

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Malaria
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