Malaria Surveillance

 

MALARIA SURVEILLANCE

Objectives of malaria surveillance

Malaria surveillance connotes the maintenance of an on-going watch/ vigil over the status of malaria in a group or community. The main purpose of  surveillance is to detect changes in trends or distribution in malaria and other  vector borne borne diseases in order to initiate initiate investigative investigative or control measures. measures. It provides a basis for measuring the effectiveness of anti-malaria programme. Malaria surveillance includes laboratory confirmation of presumptive diagnosis, finding out the source of infection and identification of all cases and susceptible contacts and still others who are at risk in order to prevent further spread of the disease dis ease..

The ultimate ultimate objectiv objective e of malaria malaria surveillan surveillance ce is preven prevention tion and

control of malaria in the community. Malaria surveillance is an essential pre-reuisite to the rational design and evaluation of a malarial control programme. Mala lari ria a surv survei eill llan ance ce is an inte integra grall part part of rim rimar! ar! "eal "ealt# t# Care Care !. Ma s!stem

"The "The disea disease se load# load# or "di "dise sease ase poten potentia tial#l# of malar malaria ia in the commu communit nity y is governe gov erned d by differe different nt paramet parameters ers such such as $infecte $infected d persons% persons%,, "suscept "susceptible ible persons pers ons#, #, and $vector $vector and env environ ironment mental al conditions conditions%. %.

&lthou &lthough gh the case

detection and its treatment is not the end of all endeavours, early detection of a case case and and its radic radical al treat treatmen mentt would would redu reduce ce the the risk risk of infect infecting ing vecto vector  r  mosuitoes mosuito es and thus reducing transmission transmission of malaria in the communi community ty.. The timely collection and e'amination of blood smear is the key element in the (ationall Malarial )ontrol *trategy. (ationa *trategy. If all the the detected detected cases cases are given given radical radical treatment early, it will certainly lead to depletion of the human reservoir of  malaria parasite in the community.

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'ort 'ortni nig# g#tl tl! ! (om (omic iciiliar liar! ! vis visit its s

+nder +nd er the (ation (ational al ector ector orne iseases iseases )ontrol )ontrol rogramme, rogramme,

the active active

case cas e detectio detection n is carried carried out by multipu multipurpos rpose e health health workers workers 0male1 0male1 under  under  primary health health care system. The fortnightly fortnightly periodicity periodicity of domiciliary visits suits suits the technical reuirement of malaria disease management. y fortnightly visits a large number of secondary cases can be avoided in the community where malaria mala ria transmiss transmission ion is seasona seasonall but well establish established. ed.

)ompone )omponents nts of the

activities under the active case detection during fortnightly visits are2

0i1 0i1

search rch for for a fev fever cas case or who who had had fev fever in bet between the the vis visits its of  M3

0i 0ii1 i1 0iii1 0iii1

coll collec ecti tion on of blo blood smea smearr fro from m suc such h cas cases es admin administ istra ratio tion n of app appro ropri priate ate antianti-mal malar arial ial0s1 0s1

Technical justification for a fortnightly blood smear collection is based on transmission dynamics of malaria. The incubation interval in case of P.vivax   is is appro'imately !! days while for P.falciparum  it is 45 days. days. Thus, surveillance surveillance cycle of less than one incubation interval will catch most of the secondary cases cas es before before the commencem commencement ent of ne't cycle.

Throug Through h this activit activity y, the

malaria surveillance can be measured. Incubation interval) It denotes the duration of the full cycle of malaria

parasite. It is the sum of the time taken for the development of the parasite in the mosuito and that in the human being.

6owever, 6owev er, over the years, the strength of the M3s0M1 has been depleting. There is shortage shortage of M3s in all all the states. In some states states the shortage may be as high as 789 or more of the sanctione sanctioned d strength. strength. :or the timely timely and regular regu lar surveillan surveillance ce these field level functionar functionaries ies are crucial. crucial.

The rimary rimary

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6eal 6e alth th )are )are syst system em in our our coun countr try y prov provid ides es one one M30m M30mal ale1 e1,, for for 4888 4888 populat pop ulation ion in hilly and tribal areas areas and 5888 populat population ion in other other areas. The The manpower envisaged under the plan is adeuate to cater to the needs of the active case detection for malaria control if all the positions of M3s are filled.

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%$%$'ev 'ever *r *reatm eatmen entt (ep (epot ots s +'* +'*(s (s,,

To avoid delay in detection of cases which occur in between visits of M3, it can be supplemented with establishment of :ever Treatment epots in villages especially in areas which are remote/ inaccessible and have low population density, for e'ample in hilly terrain of ;harkhand, )hattisgarh and M and arid areas of <ajasthan. <ajasthan. The :T holder holder should be given given training for one one or two days at the 6) 6eaduarters in the collection of blood smears, administration of presumptive treatment, impregnation of bed nets, promotion of larvivorous fish etc. 6e should be paid T&/ T&/&/hono &/honorarium rarium as per guidelines of () () for attending training.

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-loo. smear collection is important

lood smear collection is necessary to have parasite confirmation, especially in view of the fact that large areas in the country have predominant infection with P.falciparum.

Ther There e are are some some areas areas wi with th poor thera therapeu peutic tic effic efficacy acy of the

chlor chlorou ouine ine or sulfa sulfado do'i 'inene-y yrem remet etha hamin mine e agains againstt P.falciparum. In these areas, treatment treatment is done with alternative alternative drug regimen for P.falciparum  cases on microscopic confirmation of the diagnosis. Indiscriminate use of second line dr drugs ugs like like 0& 0&rte rtesun sunate ate-* -*ulf ulfado ado'i 'ine ne combi combinat natio ion n thera therapy py 0& 0&)T )T11 under under the the presumpt pres umptive ive treatmen treatmentt is always always disastr disastrous ous and precipit precipitate ates s the multi multi drug resista resi stant nt strains strains of P.falciparum. Therefore active case detection is essential for all areas of the country and the same should be further supported by establishment of :ever Treatment epots 0:Ts1.

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4.

assive Case (etection +C(,

 &ll &llopathic, &llopathic, &yurvedic, &yurvedic, 6omeopathic, 6omeopathic, *iddha medicine dispensaries dispensaries in the health sector sector should be identified identified and involved in passive passive case detection. &ll the fever cases attending the hospital should be screened for malaria and given presumptive presumpt ive treatment. treatment.  In addition  this is to be carried out at the village level by volun voluntar tary y worke workers rs drawn drawn from from local local resid resident ents s or volun voluntar tary y agen agencie cies s operating locally or &nganwadi &nganwadi workers, private practitioners etc. In view of the shortage of M3s for conducting active surveillance, it is of utmost importance that passive collection of blood smears from fever case should be increased. The istrict Malaria officers with the help of 6) staff should carry out the mapping for private clinics and other functionaries functionaries who can act as ) center. They should be imparted induction/ orientation training, in malaria before they start operating as ) center.

Malaria clinics are to be established in all the health institutions in high risk areas wherein the blood smears are e'amined on the same day and <T given.

M30M1 should contact all :Ts/ )s/ oluntary workers etc. of his area at least once a fortnight in his area and collect blood smears for transmission to labor laborato atory ry,, besid besides es reple replenis nishin hing g of micro micro slide slides s and/ and/ or drugs drugs,, where whereve ver  r  necessary.

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Rapi. 'ever S Su urve!) In case of an epidemic outbreak, every village in

th the e suspec suspected ted epide epidemic mic =one =one is cove covered red in a short short durati duration on by deplo deployi ying ng additio add itional nal man power. power. 6ouse 6ouse to house visits visits are underta undertaken ken and all fever  cases are screened screened by taking taking blood blood smears. These blood blood smears are are to be e'amined at the earliest preferably at a temporary field laborato laboratory ry at the village level.

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Mass surve!)  &s an alternative alternative to <apid <apid :ever :ever *urvey, *urvey, mass survey survey of 

the entire population may be carried out in the suspected epidemic =one. 6ere all the population irrespective of age, se' or fever status is screened by taking blood smear. *pecially children must be included in survey. survey.

To carry out these special surveys, it is always advantageous to establis establish h field laboratories by pooling laboratory technicians from adjoining 6), istricts, >onal offices or *tate 6?s. The peripheral staff should also be pooled from the neighbouring 6) areas to collect blood smears so as to cover the entire populat pop ulation ion as uickly uickly as possibl possible. e. The operati operation on should should be over over in @ to A8 days da ys..

&ll pers person ons s whos whose e bloo blood d smea smears rs are are coll collec ecte ted d shou should ld be give given n

presumpt pres umptive ive treatment treatment or mass radical radical treatment treatment..

lood lood smears collected collected

should be e'amined within !B hours.

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(rug (i (istribution Ce Centre +( +((C,

If it is not possible to have have :T, the medical officer should establish ). The function of )s are the same as those of :Ts, e'cept that the cs do not take blood slides but administer administer drugs to fever cases. olunteers olunteers identified identified for  running )s should be imported one-two day induction/ orientation training in identification of fever cases, administration of presumptive treatment, promotion of preventive measures like distribution C impregnation of bed nets, larvivorous fish, source reduction etc. for vector control.

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E2amination o off bl bloo. sm smears

The blood smears collected by &) C ) are to be e'amined e'peditiously. +nder the current situation, in most of the places, there is considerable time lag betw be tween een colle collect ction ion and and e'ami e'amina natio tion n of blood blood smear smears s due due to inade inadeua uate te facilities.. The laboratory facilities laboratory for malaria microscopy microscopy should should be decentrali=ed decentrali=ed and brought as near near to the community as possible. possible. &ll efforts efforts should be made to

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re reduc duce e th the e time time lag betw between een blood blood smear smear collec collectio tion n and and e' e'ami amina natio tion n by utili=ing e'isting facilities available both in public C private sectors.

Annual bloo. smears e2amination rate an. its vali.it!

Malaria surveillance presumes that every malaria case will present itself with sympt symptoms oms of fever fever at some some poin pointt of time time durin during g the course course of infec infectio tion. n. There Th erefo fore, re, if all feve feverr cases cases oc occur currin ring g in the the commu communi nity ty are are kept kept unde under  r  surveillance over a period of time and their blood smears are e'amined for  malaria parasite, parasite, the total malaria parasite parasite load can be e'amined. e'amined. 6owever, 6owever, there are some some e'ceptions. e'ceptions. *ome of the mala malaria ria patients w who ho give history of  fever during the past fortnight but do not have the fever at the time of blood smear collection may not show microscopically detected parasitaemia in the peripheral blood. Dn the other hand some peripheral some afebrile persons persons can be positiv positive e for  malaria mala ria parasite parasite.. Dn account account of operatio operational nal as well as technic technical al reasons reasons fortnightly fortnight ly surveillance surveillance is recommended. Establishment Establishment of :Ts has improved surveillance status of malaria case detection as community coverage is more e'tensive.

The level of &E< depends on the number of fever case in the community. The fever rate in the community fluctuates widely from month to month and year to year. year. These fluctuations fluctuations are due to other other viral and bacterial bacterial infections prevalentt in the area. :or accurate prevalen accurate estimates of malaria endemicity endemicity,, the blood smear e'amination rate specially the Monthly lood E'amination <ate 0ME<1 rate should be eual to fever rate of the month in the community. Therefore it is necessary to ensure that all persons having fever during malaria transmission months are included in the total blood slides e'amined during the year.

The ME< norms of 8.F percent during non-transmission season and A.! to A.F perce pe rcent nt durin during g trans transmis missi sion on seas season on were were lai laid d down down in the the India Indian n Malar Malaria ia Er Erad adica icatio tion n rog rogra ramme mme..

ME< ME< should should be monitore monitored d M3 M3 wi wise se by the

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medical officer in charge during monthly meeting at the 6) in order to assess the surveillance operation in the 6) area.

In both the cases i.e. &E< and ME< the denominator is common because the entire entire populati population on is covered covered during during each each fortnigh fortnightly tly domicili domiciliary ary visit visit by M30male1. &E< is the cumulative sum of monthly rates during the year year..

3hile collecting &E< or ME<, blood slides collected by all agencies are taken into account, i.e blood smears collected through &), ), :T or any otherr voluntary othe voluntary agency during during the same period. period. 6owever 6owever,, number of blood smears collected and e'amined during a mass survey and their results should not be included while calculating &E< or ME<.

 &E<

G

(o. of blood blood smears smears collected collected during during the year year ' A88 opulation covered under surveillance

ME<

G

(o. of blood smears collected during the month ' A88 opulation covered under surveillance

:or accurate estimates of malaria endemicity, the blood smears e'amination rate especially the ME< should be eual to fever rate of the month in the communit y.  &E</ ME< is an inde' of operational operational efficacy of the programme. programme.

The

 &nnual arasite arasite Incidence 0&I1 depends depends upon the &E<. & su sufficie fficient nt number  of blood slides should be systematically obtained and e'amined for malaria parasite to work out accurate &I.

Sli.e ositivit! Rate +SR,)

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The *lide ositivity <ate among the blood smears collected through both active and passive surveillance gives a more accurate information on distribution of  malaria infection infection in the community community over a period period of time. Monthly *< *< can be calculated to find out the seasonal rise and fall in malaria prevalence in the co comm mmun unit ity y.

*< *< amon among g chil childr dren en !-H !-H years ears of age age can can be util utili= i=ed ed for  for 

comparis comp arison on with with pre-cont pre-control rol )hild )hild arasit arasite e <ates <ates to assess assess the impact impact of  control measures measures on local local malaria endemicity endemicity and and transmission. transmission. *< in the age group of less than one year 0Infant arasite <ate1 can be utili=ed for  assess ass essment ment of the impact impact of control control operatio operations. ns.

The *< of blood blood slides

collected from cases currently having fever will be higher than the *< of the slides collected from cases with history of fever. Therefore, higher positivity rates are obtained obtained in blood smears smears collected collected at the ). Tr Trends ends in *< can be utili= utili=ed ed for pred predict icting ing epide epidemic mic situa situatio tions ns in the area area.. If month monthly ly *< *< e'ceeds by !  times of the standard deviation observed in *< of the preceding 4 years or preceding 4 months of the same year, an epidemic build up in the area can be suspected. suspected. Monthly or yearly yearly trends of *< are utili=ed utili=ed to study the impact of control operations.

*< is measured as follows2

(o. of (o. of blo blood od smear mears s fou found nd posi positi tiv ve for for mala malari ria a par parasit asite e (o. of blood smears e'amined

J A88 A88

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