According to V P Sharma, several states have reported
instances of falciparum with advanced resistance to chloroquine. Resistance to sulphalene / sulphadoxine and pyrimethamine groups of drugs, amodiaquine, mefloquine, a banned
drug sold unofficially, and quinine, the ultimate choice in
complicated cases, is also on the rise.
Resistance to insecticides like DDT is common; malathion
and dieldrin have joined the list as well. Recent reports in the
Indian Journal of Malariology reveal that resistance to even
multiple insecticide combinations is developing. Synthetic
pyrethroids (insecticides which do not have long-term residual
effects) such as lambdacyhalothrin are known to be more
effective and environmentally safer than insecticides in use,
but their cost is prohibitive. Chemical larvicides such as paris green, temephos or fenthion and
biological larvicides such as
the bacteria, Bacillus
thuringenesis and B sphericus
can also be
sprayed over water bodies.
Formulations of biolarvicides,
developed and field-tested by
the MRc and NMEP, were recently
cleared for use in mosquito
control.
Experts attribute malaria's
resurgence mainly to the failure
of
peripheral public health
institutions. About 40 per cent
of
posts in India's health care
centres lie vacant, according to
V P
Sharma. NMFP officials say that
most primary health care centres (PHCS) do not have
microscopes in working order.
Even in
fully functional PHcs, blood
slides accumulate for four-six
weeks, delaying diagnosis and
radical treatment. In most villages, the drug distribution
centres and fever treatment
depots
for malaria care are either
non-existent or defunct.
Insecticide spraying operations
are either not conducted,
or are incomplete or ineffective
in terms of the choice of the
insecticide, area covered,
number of required rounds and
adulteration. The collapse of
the health surveillance system
has
resulted in adhocism. Funding
for malaria research is in a
worse bind. Under the NMEP'S
modified plan of operation
(1977), malaria control costs
came to be shared equally by the
Centre and the states.
The subsidy cuts under the
structural adjustment programme brought budgetary
allocation down to Rs 72.45 crore
in 1991-92, and to Rs 50 crore
in 1992-93. Subsequently, the
allocation was increased to Rs I
10 crore, but included programmes for kala azar, filaria,
Japanese encephalitis and
guinea worm as well. The Union
government is currently
negotiating a us $140 million
World Bank loan to fight malaria in the metros and tribal
areas.
D Banerjee, public health expert
and professor emeritus at
the Centre for Social Medicine
and Community Health,
Jawaharlal Nehru University, New
Delhi, says,Unpardonableacts of omission and commissionby the political leadership ...have led to a sharp decline inthe quality of public healthservices... When there was anoutbreak of malaria in Rajasthanin 1994the malaria controlmachinery of the state wasalmost non-existent in theaffected villages... theafflictedpeople had to Cry Out to NGOSfor help." VHAi activists pointout that health officials tendto suppress malaria incidencefigures (during the 1994Rajasthan epidemicthe officialfigureof annual parasite index was0.59independent surveys'showed this to be above 5.0).
A country-wide review of malariacontrol strategies wasundertaken in 1995followingwhich a Malaria ActionProgramme (MAP) was launched.Under MAP'high risk' ruraland urban areas were identifiedfor accelerated control measuresdrug policies andtreatment schedules. Vectorcontrolmeasures were revisedwithemphasis on appointment of voluntary link workers at thevillage levelupgradation offacilitiesand intersectoral coordination.But experts point out thatmany of the changes - selectiveinsecticide sprayingfor one- suggested under MAP aretechnical and shortsighted.
In keeping with India'scommitment to the October 1992WHO global malaria controlstrategythe government draftedanational malaria controlstrategy in 1995. The newstrategyemphasises decentralisationepidemiological approaches in malaria controlcommunity participationmanagementinformation systems and health educationamong other things.
Till datethe responsibility for malaria control in the entirecountry had mostly rested with the NMEP. Under the proposednew strategythe financialtechnical and administrativeresponsibilities will be shared by major establishments in- theprivate and public sectorssuch as megaprojectstea / coffeeplantationsirrigation projects or railways / airports / seaports. The NMEP and MRc directors and V S Orlov of the WHO hadjointly recommended in 1994 that health impact assessmentbe made an integral part of the environmental impact assessment of all developmental projects.
Malaria research has several aspects: developing newdrugsvaccinessimple diagnostic methodsinsecticides andlarvicidesmethods of sterilising mosquitoesepidemiologicaland entomological studieshost-parasite interactionsimmunology of the disease andfinallyecology.
Experts strongly argue for bio -environmental control ofmosquito breeding by spraying larvicidal microbesorthrough fish species such as gambusia or the gupp MRC Scientists have identified at least four other species of fishtheDanio rerioAplocheilus panchaxOryzias melastigma andAapia mossambica which are known to feed on mosquito tar -vae. Combining mosquito control with rearing fish for consumption and profit has yielded encouraging results.Moreoverthe estimated cost of biocontrol could be as low asRs 4.97 per capita per yearas compared to Rs 6 using chemical insecticides.
Impregnated bednets are being increasingly recommendedfor malaria controlfollowing encouraging results in Orissaand the north-east. These bednets are impregnated twice ayear with synthetic pyrethroidsoffering effective protectionfor six-eight months from mosquitoesbedbugs and headlice.
Among the new drugs waiting to be introduced in themarket is a Chinese herb derivativeArtemisia annuapopularly known as Qinghaosu in China. Artemisinthe raw material.was identified as a potent antimalarial and analysed in Chinain 1972. Introduced by WHO in VietnamThailand and Cambodiait successfully curedmulti- drug- resistant malariacases. Another Chinese herbaldrugPyronaridinehas beenfound to be 100 per centeffective in the early stages ofmalariaaArding to a report in TheLancet (January 1996).
In Indiaclinical trials ofArteethera derivative developedby the Central Drug ResearchInstitute (CDRI)Lucknowarecurrently underway. The CentralInstitute of Medicinal andAromatic Plants (CIMAP)again inLucknowhas successfullyadapted the plant for cultivationin Indiaand also developedan improved method for extractingarternisinic acid and converting it into artemisinpavingthe way for its indigenouscommercial production. A WHOcommittee has recommendedthat in order to avoiddevelopment of resistance toartemisinits use should be restricted toonly those regions where multiple drug resistance is rampant.
Indigenous production and sale ofmefloquin was clearedby the government in March thisyear. The technology for theproduction of the drug is alreadyavailable with the IndianInstitute of Chemical TechnologyHyderabad.
The MRC is currently conductingclinical trials for a drugdeveloped by the CDR1. The drugcodenamed Compound80has been found to beeffective in curing monkey malaria; the results of human trialsare awaited. MRC scientists arealso assessing the antimalarialproperties of a wild herb fromBastarMadhya Pradeshlocallycalled bhuineem. The Centrehas applied remote sensing andgeographical information systems to identify malariatransmission conditions inGujarat's Kheda district.
Indian Council of MedicalResearch scientists at Port BlairAndaman & Nicobar Islandshaverecently found a plant thatis used by the local Onge tribeand could provide yet anotherweapon to fight malaria. -But thecontroversy on intellectualproperty rights over the plantproduct is likely to delay itsinduction into the antimalariaprogramme.
Scientists at the IndianInstitute of ScienceBangaloreareworking on a drug which attacksthe heme biosynthetic pathway of the P berghei which causesmouse malaria. According todirector G Padmanabhanthefinding may help in fightinghuman malaria too. Ais team hasalso developed a diagnostickit in collaboration with AstraResearch CentreBanglorebased on non-radioactivedetection Of DNA of the parasiteinblood samples without amicroscope.
Bangalore University's Centre for Applied Geneticsresearchers have taken adifferent route to beat malaria -bygenetically modifying mosquitoesso that they cannot breed.According to director N J Shettythey have already succeededin inducing genetic sterility inthe male Anopheles (Anstephansi and An fluviatilis).The researchers have alsoidentified a strain of femaleAnopheles that is resistant to themalarial parasiteand the genethat imparts this resistance.
The idea of controlling malariathrough genetically engineered mosquitoes dates back toChris Curtis' (of the LondonSchool of Hygiene and TropicalMedicine) efforts in the '60s.Laboratories in many countriesare still pursuing the idea.Howeverscientists such asAndrew Speilman of HarvardUniversityUSAfeel that suchhi-tech approaches divertmoney and attention from the lessglamorous conventionalmethods. Indian scientists alsopoint out that research intoepidemiologyvector behaviourecology and public health arenot receiving adequate attention.
There are three major stages inthe life-cycle of the parasite which are targets for vaccine development:
A vaccine based on sporozoites is designed to preventinfection.
Vaccines based on the asexual blood stages of the parasite(merozoites) will not prevent infectionbut can reduce oreliminate parasites in the blood.
Vaccines directed at the sexual stages of the parasite (gametocytes) aim to interfere with the ability of the parasite toinfect mosquitoes and thereby prevent transmission of thedisease.
Ideallya vaccine aprist malaria should contain all threefeaturesbut since the cell surface characteristics of each stageof the parasite are differentthat would be possible only froma 'cocktail' of antigens (cell surface proteins) of all stages. About 45 different proteins of the parasite have been identified so farof which about 15 are considered potential targetsfor vaccine development. A vaccine developed by a group ofAustralian researchers is undergoing trials since 1994 in USAand Africa.
According to V S Chauhanconventional vaccinesdesigned to generate antibodies against the parasite are notlikely to provide full protection. They also need to activate the'killer cells' (T-cells) of the human immune system.Fortunatelythe parasite does carry some markers on its cellsurface which can also activate these T-cells. Identifying andincorporating them into the 'final cocktail' will get the bestresults. Chauhan's team has identified some such markers. Asimilar strategy is being followed by researchers led by AdrianHill at the Institute of Molecular MedicineOxfordUK.
There are no magic bullets to beat malaria as yet. Settingaside eradicationbetter public health management practicesstrong primary health care infrastructure and emphasis onpreventive measures and community participation have thepotential to reduce malaria incidence and make the WHO'sdream of a one-fifth reduction in malaria incidence by 2000 AD- in at least 75 per cent of the affected countries - a reality.