Dr R.N.RoyAssociate Professor

Department of Community Medicine

MalariaA febrile illness caused by asexual plasmodium

parasite transmitted by infected female anopheles

mosquito

Plasmodium genus of parasite infect RBC in human

Occasional infections of monkey with P. knowlesi,

Magnitude of problems

About half the world’s population (3.3 billion) in live in

areas(109 countries & territories) endemic for malaria

Estimated 247 million malaria cases in 2006, of which

91% were due to Pf

Around 40% of the global population at risk

of malaria resides in SEA Region

AFRO: African Region AMRO: Region of the Americas SEARO: South-East Asia Region WPRO: Western Pacific region EMRO: Eastern Mediterranean

Malaria Burden in India During Pre- control era(1953) Annual Incidence was

75 mil / (22% of population) and 0.8mil death/ yrDuring 2008 incidence was 1.53 million & half of

these were Pf & 1055 deaths reportedAbout 88% of malaria cases & 97% of deaths

reported fromNortheastern (NE) States, Chhattisgarh, Jharkhand,

MP, Orissa, AP Maharashtra

Gujarat Rajasthan, W B Karnataka

Problem in India

Major epidemiological types in India

1.Tribal malaria

2.Urban malaria

3.Malaria in project area

4.Border malaria

Serious problem in NE statesPerennial malaria transmissionPredominance of falciparumDrug resistance

EPIDEMIOLOGY OF MALARIA :Agent factors

Four species :

(1)P. Vivax – causes BTM

(2) P.Falciparum-causes MTM

(3) P.Malariae-causes quartan malaria

(4) P.Ovale (not in India)

Host factorsAge: Parasitemia is low during infancy due

to maternal antibodyDuring first few weeks show resistance to Pf

infection due to fetal Hb Pregnancy: increase risk in

pregnancy :anemia , LBW delivery.

EpidemiologyReservoir of infection: Human

(Exception- chimpanzee in Africa may carry P. malariae)

Conditions for a successful reservoir:Must harbor viable & mature gametocyte of

both sexes in sufficient density

Route of transmissionBy bite of infected female anopheles

mosquito

Blood transfusion, needle stick injury,

sharing needles, organ transplantation

Congenital malaria- mother to foetus

Genetic factors

HbF and Thalassaemia protect against

malaria

Sickle cell trait (AS Hb) have higher

immunity against P. falciparum

Person with ‘Duffy negative ‘ RBC are

resistant to vivax infection

Environmental conditionsUrbanization,Industrialization and construction projectsConsequent migration, Deficient water and solid waste managementIndiscriminate disposal of articles (tyres,

containers, junk materials, cups, etc

LIFE CYCLE OF PLASMODIUM MOSQUITO Mosquito is definitive host (sexual

multiplication takes place)Mosquito picks up gametocytes from

infected person in gut converted into gamete, zygote, ookinets, oocist, sporozoites finally sporozoites reach the salivary gland (takes about 8- 25 days)

Other factors: Poor socioeconomic and housing conditions, population mobility some human habits like

sleeping out of doorNomadism refusal of spray activities etc contribute to

causation of malaria .

LIFE CYCLE OF PLASMODIUM IN HUMAN Man -intermediate host (undergo asexual reprodn.)Hepatic phase : Mosquito bite inoculate sporozoites -

reaches hepatocyte by 30mts multiply to form hepatic schizonts mature to daughter merozoites and released in sinusoids

Erythrocytic phase: Merozoites reach blood stream invade RBC in RBC multiply & develops schzoints RBC ruptures 48 or 72 hourly releasing cytokinin, TNF pirogens

Some merozoites convert & develop into gametocyte

PathophysiologyIncubation period: infective mosquito bite to onset of

sign and symptoms = 9-30 daysIP depend upon species of parasite, host immune status,

infecting doses and use of antimalarial treatmentOnly erythrocytic parasitic stage causes clinical disease Relapse: after primary attack with out subsequent

mosquito bite. Recrudescence: Reappearance of clinical malaria or

M.P in blood, which remain dormant in RBC.

VECTOR

Only female Anopheles mosquito carry parasite and infect human

Vector factors for transmissionVector densityMan biting rate & frequency of blood

mealTime and place of man - mosquito

contactMan - cattle ratioFlight rangeVector’s susceptibility to infection

IMPORTANT VECTORS OF MALARIA IN INDIASpecies Distribution Breeding

An. culicifacies Commonest, particularly in rural

Fresh water, in rice field etc

An. stephensi Urban & industrial areas

domestic a & peri-domestic artificial water collection ( e.g tanks, wells, cisterns etc.)

An. dirus N.E region Forest pools and fringes.

An. fluviatilis Foot heal region Moving water, irrigation channels, rice fields, shallow wells etc

An. minimus N.E Region, and adjacent WB

Shaded slow flowing streams with grassy margins

An. sundaicus Costal region Brackish water

Secondary vectors

Annularis ,Varuna , Philippinensis

Critical density for transmission

Critical density (Catch PMH)

A culicifacies/ Stephensi 3.3

A. Fluviatilis 0.4

A. Sundicus / philippinensis 1.3

ENTOMOLOGICAL INDICES Vector density (Man Hour Hand Captures ): Nos

anopheles collected per man hr. catchMosquito infection rateMan biting rateHuman Blood Index-indicate anthrophilismAv. nos of larva per dip

ENTOMOLOGICAL INDICES …. PER MAN HOUR DENSITY:

No. of mosquitoes collected =--- ---------------------------------------X100

No. of man hours spent in search High vector density indicates high potential for transmission

SPOROZOITE RATE (%): No. of females positive for sporozoites

= --------------------------------------------------x 100 Nos. dissected

Suspected case of malaria A patient with fever but without any other obvious cause of fever

Cough and other signs of respiratory infectionRunning nose and other signs of coldPelvic inflammation indicated by severe low

backache, vaginal discharge , urinary symptomsSkin rash suggestive of eruptive illnessBurning micturitionSkin infections e.g. boils, abscess, infected woundsPainful swelling of jointsDiarrhoeaEar discharge

Lab diagnosis:

All suspected fever cases be investigated

1. Blood smear examination/Microscopy

2. Rapid diagnostic test (RDT)

How & when to use RDT / Smear Exam

Where microscopy result is available

within 24 hrs.

(Only microscopy done)

Treatment based on

slide-result

Where microscopy result is not available within 24hrs

(Pf RDT + Slide taken)

RDT –Ve

Slide microscopy

Treatment

RDT +Ve

Treat Pf

Discard slide

EPIDEMIOLOGICAL SURVEILLANCE

ASSESSMENT OF PROBLEM (MALARIOMETRIC MEASUREMENT)

 EPIDEMIOLOGICAL SURVEY 1.Proportional case rate2.Spleen rate 3. Infant parasite rate4.Children parasite rate-(% of 2-10 yr children ē MP

in blood)5.Annual Parasite Incidence (API)6.Annual Blood Examination Rate (ABER)7.Slide Positivity Rate (SPR)8.Slide falciparum Rate (SFR)9.Annual falciparum rate (AFR)

Child Spleen Rate(CSR)

% of 2-10 yr children ē enlarged spleen

Significance :25-40%= Endemic

>40%=Hyper endemic

Infant parasite rate(IPR)

Most sensitive index for recent transmission of malaria.

# Positive for MP IPR= -----------------------------------------X100 # Blood slide examined from

infants

Annual Blood Examination Rate (ABER)

Nos of smears examined & (RDTs +Ve) in a Yr.ABER = ----------------------------------------------------------X100

Total Population under surveillance

Index of operational efficiency of surveillanceABER should be equal to fever rate in the localityABER should be > 10% of populationMonthly Blood Examination Rate should be >1% of

population during the transmission season

Annual Parasite Incidence (API) # of +Ve smears & +Ve RDTs in a yearAPI=------------------------------------------------ X

1000 # Population under surveillance

Used to stratify malarious areas Disease burden in community

Slide Positivity Rate : % of slide positive for parasite

Slide Falciparum Rate : % of slide positive for Pf

SFR pinpoints areas of Pf preponderance for prioritizing control measures

P.falciparum percentage (Pf %)

Surveillance in malaria

Passive Case Detection- Collection of blood slides in Clinic/ institution & treatment.

Active Case Detection- system of detecting malaria cases (blood slide collection ) by HW through domiciliary visits

Mass blood survey- Examination of blood from all persons in a community (during epidemiological investigation around positive cases)

DRUG SCHEDULE FOR MALARIA Diagnosis TreatmentP.Vivax

Chloroquine: 10mg/kg on D1, 10mg/kg on D2 & 5mg/kg on D3)

Primaquine: 0.25 mg/kg daily for 14 days.

Uncomplicated Pf

Artemisinin based Combination Therapy (ACT)

Artesunate 4 mg/kg daily for 3 days plus

Sulfadoxine (25 mg/kg) & Pyrimethamine (1.25 mg/kg) on Day 1 single dose

Primaquine(0.75mg/Kg) preferably on day 2Pregnant & uncomplicated Pf

1st Trimester: Quinine salt 10mg/kg 3 TDS X 7 days

2nd & 3rd Trimester: ACT as per dosage given above.

(Pv + Pf) Full course ACT + Primaquine 0.25 mg / kg daily for 14 daysClinical malaria

Suspected malaria cases :Full course of chloroquine

When parasitological diagnosis available -specific treatment

Age-specific drug schedulesAge

(years)

Chloroquine (150mg base)

Day 1 Day 2 Day 3

< 1 ½ ½ ¼1-4 1 1 ½5-8 2 2 19-14 3 3 1½15+ 4 4 2

ChemoprophylaxisShort term chemoprophylaxis (up to 6 wks)

(e.g. travelers from non-malarious areas) Doxycycline 100 mg daily in adults or (1.5mg / kg

OD)above in children , started 2 days before reaching endemic area continued for 4 weeks after leaving

Contraindication : Pregnancy & children < 8 years.Chemoprophylaxis for longer stay (> 6 wks) (e.g Military & paramilitary troops in malarious areas

duty ) Mefloquine 250 mg weekly for adults Mefloquine 5 mg/kg for children Contraindication of Mefloquine : H/O convulsions, &

neuropsychiatric problems

MALARIA CONTROL ACTIVITIES & PROGRAMME IN INDIA Problem status

& initiativeSalient features

Before 1953 there was 75 mil cases and 0.8 million deaths → Introduced NMCP (1953)

‘National Malaria Control Programme’ Objectives: ↓ malaria transmission, cease to be a public health problem Strategies: 1) Anti-malarial treatment( institutional cases) 2) Residual insecticide spray with DDT

Encouraged by success of NMCP (2 million cases per year in 1958) eradication programme was take-up in 1958

National Malaria Eradication Programme’ To stop transmission by destroying entire vectors & elimination of reservoir Strategies: 1) Two round of DDT spray in all area 2) Active & passive surveillance 3) Presumptive & Radical treatment

Contd….

NMEP↓cases to 0.1 mil. in 1966, but set back resulted due to technical, operational administrative failures →Resurgence of malaria cases & deaths →Eradication attempt discarded & introduced MPO in 1997.

‘Modified Plan of Operation’ Vertical approach was replaced by horizontal approach. Objectives: Elimination of deaths, reduction of morbidity & maintenance of achievement

Strategies: 1) Stratification of rural area based on API and differential vector control measures 2) Active & passive surveillance 3) Presumptive & radical treatment

Intervention in area with API ≥ 2

1. Residual spray with 2 round DDT/3 round Malathion

2. Surveillance/ Treatment of cases

3. Entomological assessment

Intervention in area with API<2

1.Focal spray around house with Falciparum

2. Surveillance/ Treatment of cases

3. Epidemiological investigation

4.Follow up

Continued..

Implementation of MPO, UMS(‘71) & Pf containment progm. (’77) incidence & death ↓but resurgence in some area →MAP

Malaria Action Programme (MAP) 1995:■ Areas divided in High risk & Low risk area based on certain epidemiological criteria ■ Priority spray operation and differential treatment for high-risk area

Area with adverse epidemiological parameter→EMCP1997

‘Enhanced Malaria Control Project’ Strategies: Case detection, prompt treatment, vector control and community participation

1999 National Anti Malarial Programme :Objectives and strategies same as MAP &MPO

Continued …

Continued ..

NAMP ↓ national API but some areas register high API →IMCP 2005

Intensified Malaria Control Project: Special inputs RDTs, ACT, Insecticide Treated Bed nets (ITNs) and Health Systems Strengthening (HSS) were provided.

2003-04

NVBDCP

Convergence of numbers of vector borne programmes:Malaria, Filaria, JE and Dengue under National Vector Born Disease Control Programme

Strategies: Integrated vector control and promotion of insecticide treated bed net

2006 ACT introduced in areas showing Chloroquine resistant falciparum malaria.

Continued ..

NATIONAL ANTI-MALARIA PROGRAMME1999

Under NVBDCP Objectives: Prevention of deaths due to malariaPrevention of morbidity due to malariaMaintenance of ongoing socioeconomic

development

Strategies

1. Surveillance and case management Case detection (passive and active) Early diagnosis and treatment

2. Integrated Vector Management (IVM)3. Environmental Management4. Stratification of the problem

Area with API<2 Area with API ≥2

5. Community Participation & BCC6. Monitoring and Evaluation of the

programme

Integrated Vector Management (IVM)

Use of a range of biological, chemical and

physical interventions of proven efficacy,

separately or in combination, in order to

implement cost-effective control and reduce

reliance on any single intervention

IVM Includes:

Rotation and & safe use of insecticides including management of resistance

Indoor Residual Spray (IRS)

Insecticide Treated bed Nets (Tins) / Long

Lasting Insecticidal Nets (LLINs)

Antilarval measures including source reduction

Vector control methods Methods of reducing human-vector contact:

Mosquito nets & insecticide treated nets (Synthetic pyrethroid) House protection with screening of windows, doors etc.Use of repellents

Anti adult measures: Indoor residual spraying with DDT/Space spraying of insecticides

Anti larval measures:LarvicidingBiological ControlSource reduction by environmental management

Anti adult measuresIndoor residual spraying with

-Organo chlorine compound : DDT

- OP-compounds : Malathion, Fenitrothion

-Carbamate :Propoxur

-Synthetic pyrethroids: Deltamethrin Space spray: Pyrithrum Out door space spray :Malathion, Pyrethrum

Anti larval measures Larviciding with MLO, Temephos ( abate), Fenthion etc.Biological Control

Use of larvivorous fish (Gambusia affinis & Poecilia reticulata)

Use of biocides: bacillus thuringiensis

Source reduction by environmental management Drainage /Filling /flushing/change of salinity

Community Perticipation & BCC Process of learning that empowers people to take rational

and informed decisions through appropriate knowledge Clear messages, communicated through different, credible

channels are most likely to bring about change. Ignorance, prejudices must be replaced by knowledge Awareness campaign programme-observe malaria week

Legislative measures:Model civic bye-laws:

‘High risk areas’Recorded deaths due to malariaDoubling of SPR during last 3 yrs provided

the SPR in 2nd / 3rd yr reaches ≥ 4%Average SPR of the last 3 yrs ≥ 5%P.falciparum proportion ≥ 30% provided

SPR is ≥ 3% during any of the last 3 yrsAny area with focus of CQ resistant P.f.

casesAggregation of labour in project area & new

settlements in endemic/receptive & vulnerable areas

Thank you