Malaria

MALARIA

Sriloy Mohanty

2nd sem,BNYS

S-VYASA

Contents…

• Introduction• Problem statement• Epidemiological

determinants• Life cycle• Host factor • Environmental factor

• Vector of malaria• Mode of transmission• Incubation period• Clinical features• Diagnosis• Control• Global policy for diagnosis and

treatment of malaria• Malaria vaccine

Introduction

• It is a protozoal disease

• Infected with parasite of the genus Plasmodium

• Transmits to man mainly by female Anopheline

mosquito

• Attack occurs in three stages

Problem statement (world)

• 109 countries are endemic for malaria• 3.3 billion people were at risk of malaria in 2006• 1.2 billion at higher risk(WHO African and SE Asia)• 247 episodes of malaria in 2006• 8,81,000 deaths in 2006,of this 91% in Africa, among

them 85% were children under 5yrs• Childhood death occurs mainly due to cerebral

malaria and anemia

Cont.…(India)

• It is a major problem in India• Mainly falciparum is prone • About 27% people lives in high transmission area• 53% people live in low transmission area• Most affected states are-Chhatisgrah,Jharkhand,

Madhya Pradesh, Andra Pradesh, Odissa, Maharasta Karnataka, Gujurat And West Bengal

Epidemiological types of malaria• Tribal malaria

– About 44 million population of tribal area contrbute about 50% of cases

– Infants,pregnant women, and young children are at high risk

• Rural malaria– It includes irrigated areas arid and semi-aridplains of

hariyana panjab and plain desert areas and subcostal areas

• Urban malaria– Major 15 cities including 4 metropolitan cities covers about

80% of malaria cases covered in rural malaria

• Malaria in project area– Means construction and developmental activites are taken

up– It provides vector breeding place, increased man-mosquito

contact

• Border line malaria– High transmission malaria belt along with international and

state borders– B’coz of mixing of population– Poor administrative control

Epidemiological determinant

• Agent– Caused by 4 species

• P.vivax(widest geographic distribution,in india 70% infection)

• P.falcifarum(25-30% infections)

• P.malariae(less then 1% infection,karnataka)

• P.ovale(very rare)

Lifecycle…

• Reservoir of infection– Infection Chimpanzees in tropical Africa– No other animals are reservoirs– Human is a reservoir– Children are more likely to be gametocyte carriers

• Period of communicability– Malaria is communicable as long as mature, viable

gametocytes in the circulating blood in sufficient density to infect vector mosquitoes

– In vivax infection-gametocytes appears in blood in 4-5 days– In falcifarum infections gametocytes appear after 10-12

days– The gametocytes always appear after the asexual lifecycle

of the parasites– Gametocytes mainly found in the peripheral blood

•

• Relapse– Usual for vivax and ovale malariato relapse more then 3

years after the first attack(due to original, sporozoit induced, liver schizonts)

– Recurrence of falciparum malaria usually disappear after 1-2 years

– P.malaria has a tendency to caused prolonged low-level asymptomatic parasitaemia(persist for 40yrs)

– In p.falciparum and p.malaria is due to chronic blood infection

Host factor

• Age– Affects all age– Infants have resistant to infection with p.palcifarum due to high

concentration of hemoglobin during first few months• Sex

– Males are more exposed to the risk of acquiring malaria then female

• Race– indivisuals with sickle-cell trait have milder illness to falciparum

then those do normal heamoglobin

• Pregnancy – Increased risk– May cause intrauterine death,abortion– Primigravid women are at higher risk

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• Socio-Economic Devlopment– Malaria has disappeared from socio-economic development– Because of the improved sanitation

• Housing – If the house have ill-ventilated and ill-lighted provide ideal indoor

resting place for mosquito• Population mobility

– Migration from one place to another– Labors connected with engineering, irrigation, agricultural and

other projects and periodic migration of wondering tribes

• Occupation– It is predominantly a rural disease– Closely related to agriculture practice

• Human habitat– Sleeping outdoors, not using bed nets, refusal to accept spraying

in house, plastering the walls after spraying• Immunity

– Immunity in human is Acquired after repeated exposure over several years

– Infants born from immune mothers are protected by the maternal IgG antibody during 3-5 months

Environmental factors• Season

– Maximum in between july-november• Temperature

– Affects the life cycle of the malaria parasite– Optimum temp. is 20-30*C in the insect vector– If the temp.is bellow 16* C then parasite development ceases and

above 30* is lethal to the parasite• Humidity

– Direct effect o n life span of the mosquito, but not in the mosquito – Relative humidity of 60%is considered necessary for the mosquito

• Altitude– In high altitudes above 2000-2500m due to unfavorable

conditions anophelines mosquitos are not found

• Rainfall – Provides opportunities for the breeding of the mosquitoes

and may give rise to endemic of malaria– However heavy rain may have adverse effect

• Man made malaria– Burrow pits, garden pools, irrigation channels, engineering

projects have led to the breeding of mosquito

Vector of malaria

• 45 species of Anopheline mosquitos in India• Few are regarded as vector of primary importance• Those are

– An.culicifaciaes(vector of rural area)– An.fluviatilts– An.stephensi(vectors of urban areas)– An.minimus– An.phillipinensis– An.sundicus– An.maculatus

• Main factors which determines the vectorial importance of mosquitoes are– Density– Life span– Choice of host(An.culicifaciaes in india,2-80%)– Resting habitat– Breeding habitats– Time of biting– Resistance to insecticides

Mode of transmission • Vector transmission

– By mosquito bite

• Direct transmission– Blood transfusion, they can live for 14 days in blood bottles

under -4*C

• Congenital transmission– Mother to newborn

Incubation period

• 12 (9-14)days for farucifarum malaria

• 14 (8-17)days for vivax malaria

• 28 (18-40)days for quartan malaria

• 17 (16-18)days for ovale malaria

Clinical features

• The peaks of fever coincide with the release into blood stream

• Typical attack comprises in three stages– Cold stage

• Lasts for 1hr• Onset with headache, nausea and chilly sansation• Temp. rises upto 39-41*C

Hot stage

Lasts for 2-6hrs

Feels burning hot and casts off his cloths

Skin becomes hot and dry

Respiration is high

Sweating stage

Lasts for 3-4hrs

Fever comes down with profuse sweating

Skin becomes normal and cool

• P.vivax infection symptoms are same but more regularly divide into hot and cold stage

• P.malariae attack resembles to P.vivax but the cycle is of 72hrs instead of 48hrs

• P.ovale infection is same as P.vivax infection but can cease after a few paroxysms even if no treatment is given

Diagnosis • Demonstration of the parasite in the blood

– Two types of blood films are needed– Thick for searching the parasite– Thin is for identifying the species

• Malaria fluorscent antibody test– Usually becomes positive after primary infection is cured– It is not for a current case– It helps in epidemic studies

Control

• National Drug Policy on Malaria,2007

– Emphasis on complete treatment in diagnosed cases of

malaria rather then one single dose presumptive treatment

to suspect the case of malaria to avoid choloroquine

resistance in p.palcifarum

– The first line of treatment is choloroquine

Sever and complicated malaria• Choice of antimalarial is quinine injection

– 10mg/kg body wt.– I.V drip in 5% dextrose saline to be runover 4hrs– Total duration of treatment is of 7 days

• Injectable form of artemisinine derivatives may be used for the management of the sever complicated malaria in adult and non-pregnant women only

• The recommended injectable dosages are…•

• Artesunate – 2.4mg/kg bw – IM or IV followed by 1.2mg/kg bw once daily for 4 days– Total duration is 5 days

• Artemether– 1.6mg/kg bw – IM followed by 1.6mg/kg bw daily for total 6 injection or

twice for 3 days

• Artether– 150mg daily IM for 3 days – Only for adult

• Artemisinine– 10mg/kg bw at 0 and 4 hours followed by 7mg/kg bw at

24,36,48 and 60 hours

Toxic hazards of drugs

• Choloroquine has few side effects like nausea

vomiting blurrading of vision headach

• Cases of retinal damage has been reported but only

in a person exposed to large comulative dose over

many years

• Choloqeiune should not give to empty stomach

• Symptoms may be of three types– Plasmosid types

• Rare toxic manifestation involving the CNS – Gastrointestinal

• Cramps,nausea and vomiting– Cardiovascular

• Most serious toxic menifestation

Mass drug administration

• It is recommended for highly infected endemic areas• It is not recommended to children under 5 b’coz

– Impossible to achieve continuous suppression in a significant proportion of the population

– Interfere in the development of promotive immunity– May accelerate devlopment of drugs resistance– May increase the risk of retinopathy

Chemoprophylaxis • It is recommended for the travellers from non

endemic areas and as a short term measure for soldiers, police and labour forces serving in highly endemic area

• The risk of serious side effects associated with long term prophylactic use of chloroquine and proguanil is low

• Anyone who has taken 300mg chloroquine weekly for over 5 yrs and require further prophylaxis should be screened twice yearly for early retinal changes

• If daily dose of 100mg chloroquine have been taken screening should start after 3 yrs

• Pregnant women living in areas where transmission is very intens may lead to parasitaemia, causing low birth weight, anemia

Active intervention measures• Stratification of problem• Vector control strategy

– Anti-adult measures

• Residual spray– Spraying indoor surface of house– DDT is discovered in 1940– Most effective measure to kill the mosqueto

• Space application– Major anti-epidemic measure– Involves application of pestisidesin the form of fug or mist using

special equipments

• Individual protection– Man-vector contact can be reduce by

• Using nets, protecting cloth, coils, repellents• Anti-larval measure

– Larvicides• Using the anti larval measures such as oiling the

collection of standing water or dusting them with paris green effectively controlled malaria

• Some moderm larvicides such as temephos which confer long effect with low toxicity are more widely used

Source reduction• Techniques to reduce mosquito breeding sites which

includes drainage or filling, deepening or flushing, management of water level, changing the salt content of water and intermittent irrigation are the classical methods of malaria control

• Integrated control– In order to reduce too much dependence residual

insecticides, increasing emphasis is being put on integrated vector control methodology which includes bio-environmental and personal protection measure

Global policy for diagnosis and treatment of malaria

• The Govt of every country affected by malaria has a National control policy covering prevention and case management

• Objectives are– Ensure rapid cure of infection– Reduce morbidity and mortality, including malarial related

anemia – Prevent the progression of uncomplicated malaria into

severe disease – Reduce the impact of malarial infection on the fetus during

pregnancy

• Reduce the reservoir infection• Prevent the emergence and spreading of drug

resistance and prevent malaria in travellers

• There are many organization which have worked to established the goals of WHO are– Roll Back Back malaria (1998)– United nations millenium declaration (2000)– Abuja declaration of african heads of state(2000)– World Health Assembly (2005)– RBM global statergy plan 2005-2015

Malaria vaccine• Vaccination against malaria is a burning issue today• Several vaccine candidates are now being tested in

africa, asia and US• A vaccine developed in columbia (SPF 66) advanced

to phase 3 trials in africa but failed to show efficacy in chiildren under 1

• Another vaccine (RTS, S/AS02) with the potential to prevent infection and ameliorate disease is being tested by GlaxoSmithKline and the MVI at PATH in Phase I trial in Gambia

• In phase II in 2002 trials of the vaccine are being conducted among the children in Mozambique, which suffers from year-round malaria transmission offering a better opportunity to evaluate vaccine performance

• This vaccine has been safely tested in adult volunteeers in Belgium, Gambia, kenya and US

• only potential malarial vaccine

Thank you…