Malaria

MalariaMalaria

Lyndon L. Lee Suy, MD, Lyndon L. Lee Suy, MD, MPHMPH

EpidemiologyEpidemiology

A science that is concerned with:A science that is concerned with:– Describing the pattern of occurrence of Describing the pattern of occurrence of

disease in a populationdisease in a population– Determining the factors that influence Determining the factors that influence

disease distributiondisease distribution– Ultimate objective of providing the basis Ultimate objective of providing the basis

for prevention & controlfor prevention & control

EpidemiologyEpidemiology

AGENT (Plasmodium sp.)

HOST (man)

VECTOR(Anopheles sp.)

ENVIRONMENT

Basic Factors In Malaria TransmissionBasic Factors In Malaria Transmission

Components of the Malaria Life CycleComponents of the Malaria Life Cycle

Mosquito Vector

Human Host

Sporogonic cycle

Infective Period

Mosquito bitesgametocytemic person

Mosquito bitesuninfected person

PrepatentPeriod

Incubation PeriodClinical Illness

Parasites visible

RecoverySymptom onset

Adapted from:CDC

HostHost Factors Inherent in ManFactors Inherent in Man

RaceRace ImmunityImmunity AgeAge SexSex

More susceptible populationMore susceptible population Young childrenYoung children Pregnant womenPregnant women Non-immunesNon-immunes

AgentAgent

Plasmodium falciparumPlasmodium falciparum Plasmodium vivaxPlasmodium vivax Plasmodium malariaePlasmodium malariae Plasmodium ovalePlasmodium ovale

VectorVector

Anopheles flavirostrisAnopheles flavirostris Anopheles litoralisAnopheles litoralis Anopheles maculatusAnopheles maculatus Anopheles mangyanusAnopheles mangyanus Anopheles balabacensisAnopheles balabacensis

Anopheles

Environmental Factors Affecting TransmissionEnvironmental Factors Affecting Transmission

Physical, chemical, biological & socio-economic Physical, chemical, biological & socio-economic environmentsenvironments

Prevailing climatic conditionsPrevailing climatic conditions In general, transmission is higher during the rainy season In general, transmission is higher during the rainy season

than during the dry seasonthan during the dry season Peaks of transmission is usually two months after the Peaks of transmission is usually two months after the

start of the rainy months & towards the end of the rainy start of the rainy months & towards the end of the rainy seasonseason

More than 90% of all malaria cases are in More than 90% of all malaria cases are in sub-Saharan Africa. sub-Saharan Africa.

Current Global PictureCurrent Global Picture

Mortality is estimated to be over 1 million Mortality is estimated to be over 1 million deaths each year. deaths each year.

The vast majority of deaths occur among The vast majority of deaths occur among young children in Africa, especially in young children in Africa, especially in remote rural areas with poor access to remote rural areas with poor access to health services. health services.

Modified from CDC Website,2001

National SituationNational Situation

Control of malaria in the Philippines in the Control of malaria in the Philippines in the 1990s had significantly reduced cases by 1990s had significantly reduced cases by 60% (from 89,047 in 1990 to 34,787 in 60% (from 89,047 in 1990 to 34,787 in 2001)2001)

Malaria remains endemic in 65 of the 78 Malaria remains endemic in 65 of the 78 provinces, 760 of the 1,600 municipalities & provinces, 760 of the 1,600 municipalities & 9,345 of the 42,979 barangays nationwide9,345 of the 42,979 barangays nationwide

At risk of malaria nationwide are 11 million At risk of malaria nationwide are 11 million Filipinos mainly living in the remote hard to Filipinos mainly living in the remote hard to reach areas reach areas

National SituationNational Situation

Endemicity is now generally moderate to Endemicity is now generally moderate to low with pockets of high endemicity low with pockets of high endemicity persisting along the provincial/regional persisting along the provincial/regional borders, in frontier areas, places populated borders, in frontier areas, places populated by indigenous cultural groups & areas with by indigenous cultural groups & areas with socio-political conflictssocio-political conflicts

It continues to be a major impediment to It continues to be a major impediment to human & economic development in areas human & economic development in areas where it persistswhere it persists

It still costs the economy over 100 million It still costs the economy over 100 million pesos to sustain control effortspesos to sustain control efforts

Category A ProvincesCategory A Provinces• 9 provinces (from 26 provinces)9 provinces (from 26 provinces)

Category B ProvincesCategory B Provinces• 23 provinces (from 22 provinces)23 provinces (from 22 provinces)

Category C ProvincesCategory C Provinces• 31 provinces (from 18 provinces)31 provinces (from 18 provinces)

Category D ProvincesCategory D Provinces• 16 provinces (from 13 provinces)16 provinces (from 13 provinces)• 13 provinces remain malaria-free 13 provinces remain malaria-free statusstatus

GEOGRAPHICAL DISTRIBUTION OF MALARIA, PHILIPPINES GEOGRAPHICAL DISTRIBUTION OF MALARIA, PHILIPPINES (Based on 5-year Ave, 2001 – 2005)(Based on 5-year Ave, 2001 – 2005)

Source: Malaria Control Program, 2006

Extent of the ProblemExtent of the Problem

Around 10.5 million population live in areas Around 10.5 million population live in areas endemic for malariaendemic for malaria

Commonly affected:Commonly affected:– Upland subsistence farmersUpland subsistence farmers– Indigenous cultural groupsIndigenous cultural groups– Forest product gatherersForest product gatherers– Settlers in frontier areasSettlers in frontier areas– Migrant agricultural workersMigrant agricultural workers– Charcoal makersCharcoal makers– Miners Miners

Malaria is not just a health Malaria is not just a health problem… problem…

it is also a socio-economic it is also a socio-economic problem that affects the well-problem that affects the well-being of the people as well as being of the people as well as

the country.the country.

Factors in the Persistence or Re-Factors in the Persistence or Re-emergence of Malariaemergence of Malaria

Inadequate program integration in health Inadequate program integration in health servicesservices

Lack of quality assurance & control in Lack of quality assurance & control in diagnosisdiagnosis

Poor public awarenessPoor public awareness Uncoordinated control effortsUncoordinated control efforts Inadequate technical expertiseInadequate technical expertise Inadequate researchesInadequate researches

Other Inter-related Socio-economic, Other Inter-related Socio-economic, Biological & Environmental Factors Biological & Environmental Factors include:include: PovertyPoverty Drug & insecticide resistanceDrug & insecticide resistance Socio-political conflictSocio-political conflict Population movementPopulation movement Climatic changeClimatic change

Current ConcernsCurrent Concerns

Delivery of treatment that gives clinical Delivery of treatment that gives clinical & parasitological cure to drug resistant & parasitological cure to drug resistant malariamalaria

Protection of current drugs in the face Protection of current drugs in the face of emerging drug resistanceof emerging drug resistance

Vector ControlVector Control

Use of insecticide treated mosquito netsUse of insecticide treated mosquito nets– Main vector control strategy in malarious areasMain vector control strategy in malarious areas– Help prevent mosquito bites & kills mosquitoesHelp prevent mosquito bites & kills mosquitoes– Target:Target:

At least 1 treated mosquito net per householdAt least 1 treated mosquito net per household Re-treatment at least once a yearRe-treatment at least once a year Coverage should be no less than 85-90%Coverage should be no less than 85-90%


Environmental management by stream Environmental management by stream clearingclearing– To increase streamflow to make it To increase streamflow to make it

unsuitable for vector breedingunsuitable for vector breeding


Seeding of streams with larvivorous Seeding of streams with larvivorous fishesfishes– To reduce mosquito density by predation To reduce mosquito density by predation

of mosquito-eating fishesof mosquito-eating fishes


Indoor residual spraying of houses Indoor residual spraying of houses with insecticideswith insecticides– To kill the adult mosquitoes that rest on To kill the adult mosquitoes that rest on

walls thereby reducing their populationwalls thereby reducing their population– Vector control in case of outbreaksVector control in case of outbreaks


Personal Protection MeasuresPersonal Protection Measures– Use of mosquito netsUse of mosquito nets– ChemoprophylaxisChemoprophylaxis– Use of mosquito repellentsUse of mosquito repellents– Screening of housesScreening of houses– Use of protective clothingUse of protective clothing

Malaria DiagnosisMalaria Diagnosis

Clinical DiagnosisClinical Diagnosis– Based on signs & symptoms & history of Based on signs & symptoms & history of

travel to a malaria endemic areatravel to a malaria endemic area– Done by all trained health workers Done by all trained health workers

especially in areas where microscopic especially in areas where microscopic diagnosis is not available within 24 hoursdiagnosis is not available within 24 hours


Microscopic DiagnosisMicroscopic Diagnosis– Gold standardGold standard– Definitive diagnosis of infection is based Definitive diagnosis of infection is based

on demonstration of malaria parasites in on demonstration of malaria parasites in blood filmsblood films


Rapid Diagnostic TestsRapid Diagnostic Tests– Uses immunochromatographic methods Uses immunochromatographic methods

to detect to detect Plasmodium Plasmodium specific antigensspecific antigens

Community Health EducationCommunity Health Education

Aims to strengthen the knowledge, Aims to strengthen the knowledge, attitude & practices of the people in attitude & practices of the people in the community in the prevention & the community in the prevention & control of malariacontrol of malaria

Drug ResistanceDrug Resistance

MortalityMortality MorbidityMorbidity Transmission in areas Transmission in areas

of low level malariaof low level malaria

Major ChallengesMajor Challenges Improving the managerial & technical capacities in Improving the managerial & technical capacities in

MCPMCP Working beyond the health sector to reach out to Working beyond the health sector to reach out to

remote communitiesremote communities Empowering the communities at risk, including the Empowering the communities at risk, including the

indigenous people, to become active partners & not indigenous people, to become active partners & not just passive recipients of health servicesjust passive recipients of health services

Detecting & responding early to control outbreaks & Detecting & responding early to control outbreaks & preventing its occurrencepreventing its occurrence

Combating drug resistanceCombating drug resistance

Guiding PrinciplesGuiding Principles Focus on the disadvantaged groups to Focus on the disadvantaged groups to

help address inequityhelp address inequity Positioning MCP to improve its Positioning MCP to improve its

performanceperformance Ensure sustainability through Ensure sustainability through

community & multi-sectoral community & multi-sectoral involvementinvolvement

Evidence based approachesEvidence based approaches

Malaria

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