6. FEVER AND MALARIA (FORTNIGHTLY FEVER SURVEYS)

6.1.STlJDY AREA:

Fortnightly fever survey was carried out initially in 22 villages

in Jeypore zone for a period of one year (19871. The result of this

study was compared with that obtained by the national programne in the

same villages in previous years I1984 - 1986). For comparison of

seasonality and spatial distribution of malaria, fever surveys were

subsequently [between March, 1988 and February, 19891 carried out in 8

villages of Jeypore (Borigumna PHC: 2 each of tophill, foothill,

riverine and plain) and 4 villages of Malkangiri zone (Mlkangiri PHC:

1 each of the above types). The description and the basis of

classification of these villages have been given earlier (chapter: 5).

6.2. METFDDS OF SLRWY AND ANALYSES OF DATA:

Surveillance workers visited each household in the villages at

fortnightly intervals. All febrile persons, those giving history of

febrile spell in between visits and those afebrile but had complaints

of mild illness such as headache, body ache, nausea, vomiting,

diarrhoea, feverishness etc. at the time of visit were subjected to

finger prick blood examination. ?he last group of persons were included

in the survey since i t is necessary to examine these persons in usual

malaria surveillance, as per WI recarmendations [Black, 1968). As the

sanpling was essentially biased (cases of fever and other mild

illness), no m i n i m target was fixed. Informal consent for obtaining

finger prick blood smear was taken from all individuals and in !he case

of children, from their parents/ guardians.

To study the actual coverage of population in the fever surveys,

presence/ absence of all family rncrbers was recorded every fortnight in

4 villages (one of each type) in Jeypore zone for d period of 10-12

months.

Clinical diagnosis of febrile/ afebrile persons was made by a *

physician in the 8 villages of Jeypore zone whenever possible. Blood

smear was collected from all these perems (if not covered by above

surveys). This was done to study the relationship between clinical

manifestations and parasitaemia.

The blood smears collected were dehemglobinised, stained by

Giemsa and examined for parasi taemia and its grade following standard

technique (Bruce-Chwatt, 1985; also see chapter: 5.2).

A cquter data base was created for the purpose of analyses.

Apart from calculation of parasite rate ( % positivity armng those

examined: same as slide pos~tivity rate or SPR), mnthly and annual

fever or parasite incidence was calculatcrl ! K i n g tho rollowing

fonrula:

Nunber rve * Incidence = --------------- X lODD

Population

*: tve for fever or parasites ( total/ individual species) in unit time

(imnth;year).

'Ihe above parmoter is ttst:d in cnnt rol l)rngr;mlrlc!s ;]nil nloasurt:s

the fever/parasi te load in the population, since the denaninator is

population (WHC), 1964: Molineaux g g . , 1988) . This is based on the

following assunptions.

(i) All fresh cases of malaria are sycqtomatic (present with fever

or other mild illnesses),

(ii 1 the entire population is covered in every visl t .

Standard statistical methods were employed for testing the

significance of association of parasitaernia with factors like age, sex

etc. (Chi square and Fisher's test as applicable).

6.3. RESULTS OF EVE3 SUFM3 I N 22 VILLAGES [INITIAL STUDIES

I N 1987) :

A total of 5,520 blood smear slides was collected frm febrile/

s ~ t m t i c persons in 22 villages (population = 15,303) in Jeypore

zone. Of these 1,364 124.7%) were found positive for malaria parasite

[P. falciparm = 1,054; 1. vivax = 280; E. malariae = 4 and mixed - infections = 26 ) . Comparison o f data obtained from the same 22 villages

by surveillance under national p r o g r m (average of 3 years: 1984 - 1986) and that obtained in present study (1987) is shown in Table: 35.

The parasite incidence per 1,000 population was 49.5 and 89.1, under

national programne and present study respectively. The annual parasite

incidence in the entire Rorigma R1C which covers these villages was

29.6 and 26.0 per 1 ,000 population i.1 1986 and 1987 respectively,

indicating that there was nn real increase in malaria incidence in the

whole area in 1987. The relative rise in annual incidence only in the

22 villages in 1987 unlike the other parts of the PHC could therefore

be a result of effective surveillance in the present study.

During the course of the study i t was observed that villages

located at the foothills weremoremalarious. Of the 22 villages 3 were

located in the foothills and rest 19 in the plains. Analyses of data

according to these two village types indicated that the annual fever

and parasite incidence in foothill villages (531.3 and 207.8 per 1,000

population respectively) were c:nnsiderably higher colnpared tn those

Page. .I46

Table: 35

Canparison of parasite incidence betwen national p r o a r m and present study in 22 villages of Borigumna HE.

Months National programn: data Prusent s tutly tla t a (average of 1984-1986) (1987)

BSC Ntnnber Incidence BSC Nwnber Incidence ---------- ------------ ---------- ---------- +ve Pf Pr Pf +ve Pf Pr Pf

Janurary February March April May June July August Septerlxrr October Noventer Decmher

Total 3085 757 636 49.47 41.56 5520 1364 1054 89.13 68.88

Pr: any parasite. Pf: P.falciparum BSC: Blood m a r s collected and examined Incidence calculated per 1.000 population (total population = 15,303)

Page. .I47

located in plains (330.0 and 67.8 per 1,000 population respectively).

Hence in the next year, surveillance was carried out in 4 different

types of villages in two zones (Jeypore and Malkangiri) to generate

data not only on the difference in parasite load but also on the

seasonal differences if any, betwnecn the tll f ferent ecntyr1c:s of villages

in the two zones.

6.4. RESULTS OF YEAR ROIIND FEVER SURVFiS IN 4 D I F m W GROUPS OF

V I L W E S IN ?WD ZONES (March, 1988 to February, 1989):

The age and sex distribution of the population and the s q l e in

the year round fever surveys in the 12 villages (March, 1988 to

February,l989) is shown in Table: 36. Age distribution of the sample

generally resenbled that of the population [Figure: 29).

Of the 4,783 cases examined, 1,517 (31.7%) had malaria parasite

in their peripheral blood. The annual incidence of fever wes 528/1.000

population. The annual parasite incidence (API) was 167.5/1,000

population. All four species of human malarial parasites including P.

ovale (which was hitherto not recorded in any other part of India) were - detected in this locality. P. falciparm was detected in 1,158 (76.3%

of all +ves), P. in 217 (14.3% of all +ves), P. malariae in 23

(1.5% of all +ves) and P. ovale in 4 (0.26% of all +ves) persons. Mixed

infection with more than one parasite was recorded in 127 (8.4% of all

+vee) of cases and a n~ajority (102) of these had infectlonvith

Plasmdlum ovale, hltherto not recorded In India, was detected In =and foothlll vlllsges or Koraput (Section:

6 . 4 ) .

Page. . I48

Table: 36

Age specific coverage of sample in fever surveys of 12 villages in Koraput.

Age Population size Sample size %mple as % of in years* population in each

age class

Male Female Total Male Female Total Male Ferrlale Total

Total 4485 4572 9057 2320 2463 4783 51.73 53.87 52.81

*Lower limit of age class not included

Page. .I49

Age class in years*

PIOIRB: 29. Comparison of age distribution of sample in fever 8urveys with age structure of the population in 12 villages of Koraput.

Lower l i z f age class not included.

Page. . lSO

falciparm and s.

6.4.1. Age spwcific analysis of fever and parasitamia:

Age specific analysis indicated that the parasite rate [Table:

37) incrt~n~o~l ~ I V I I I I Inl,~l~l I I I V I I ~ t. I . I Z . ' l ' L 1 111 1.11~11 1 1 $ 1 [11:,11, 1 1 1 I ! , - L O ylr,il

age class (39.8%) and thereafter declined in adult age classes. The

ago specific rates for falciparlnn and reserrbled that of total

parasite rate (irrespective of species) except for the fact that

infants recorded higher rates compared to young children [Figure:

30A). Mixed infections were highest in infants which declined with age

[Figure: 30B, Table: 38). The analysis of age specific P. falciparm

gametocyte rate showed a peak in 1-2 year chlldren anddeclined

thereafter until 9-15 year age class. Young auults showed higher

gametocyte rate compared to older persons (Figure: 30C; Table: 37).

The pattern of age specific incidence (per 1,000 population in

each age class) was different from age specific parasite rate. The

pattern of incidence of fever and parasite was qualitatively similar.

Incidence increased from infant levels to reach a peak in children 1-2

years old, and declined thereafter till the adolescent age class to

stabilize in adults (Figure: 31 A; Table: 39). The patterns of

incidence of falciparm, and mixed infections were qualitatively

similar, but quantitatively at different levels (Figure: 31 A and B ) .

Parasite density index (PI>I) in the case of falciparm increased from

infant levels (2.25) to reach a peak density in 2-4 year age class

A 1 . PARASITE (TOTAL) 2. c. PALCIPARUI

-0--2- I ha.,--0'' 0----- 0-..

-.,,-----a I I I I 1

5. p. PALCIPARUM GrnTOCYTE

- 4 -

I I I I I

10 -

0 20 4 0 80 Age i n y e a r s

8 -

6 -

PICURB: 30. Age s p e c i f i c p a t t e r n s o f p a r a s i t e ( t o t a l ) , . P. f a l c i p a r u m . P . v i v a x , Mixed iril'ecLlon, Y. - -- - - - - -- fa l c iparum gametocytc r a t e s i n Lhe populaLion i n f e v e r s u r v e y s o f 1 2 v i l l a g e s i n Koraput.

4 . MIXED INFECTION RATE '

4 - 2 -

0 I I I I I

Page.. 153

Table: 38

Age specific distribution of mixed infections in fever surveys in 12 villages of Koraput.

Age in No. of cases with Total MIX RT years* n~lxed ( 8 )

Pf+Pv Pf+Fm P v + m Pf+Pv+Rn Pf+Po Po+Pv Po+Pf+Pv

Pf : P. falciparm Pv : P. v i v a Rn : P. malariae Po : P, ovale MIX RT: % i m a f e c t i o n rate * Lower limit of age class not included

M e in years

FIGURE: 31. Age specific patterns of fever (1). total parasite (2). P. falciparur ( 3 ) . P. (4). mixed infection ( 5 ) . B. malariae (6) and-E. ( 7 ) incidence. and P. - - f ~ c i p a r u r (8) and E. ( 9 ) density index in fever surveys of 12 villages.

Page. .I56

12.66) and declined thereafter gradually. P. vivax also showed a trend

similar t o 1. falciparm, but the levels were always lower and the peak

density of this parasite was in 9-15 year age class (Figure: 31C).

Tnere was no distinct age specific pattern of incidence or density

index for P. malariae and P. ovale (Table: 3 7 1 , probably due to lower

nunber of cases detected.

6.4.2. Parasitaemia in females and males:

In the year round fever survey, the parasite rate (Table: 40)

was higher (34.5%) in males compared to fomales (2!1.1\,), however the

difference was not statistically significant ( P >0.05). Age specific

analysis indicated that there was a clear quantitative separation of

total parasite rate (irrespei:tive of species), fali:ipar~nn rate and

vivax rate in the sexes beyond 4-9 years age class (Y~gure: 32 A,B 6

C ) , though qualitatively the patterns were m r e or less similar for

both sexes. Significant difference (P <0.051 in total paras~te rate

(irrespective of species), falciparum rate and rate was observed

between the sexes in age classes 20-50, 30-40 and 20-40 years

respectively. No distinct pattern of difference was observed between

the sexes in falciparm gametocyte rate and in mixed infection [Figure:

32D and E). The parasite density index for falciparm, and

malariae (2.46, 2.05 and 1.82 respectively) was higher in males when

cunpared to females (2.34, 1.88, 1.67 respectively). The age specific

patterns for femles and males Were not dls11nc.t (Figure: 331, even

Page. .I58

J)-9\ SLIDE POSITIVITY I I - - P. PALCIPARU* I

years

0 2 0 9 0 60 Age in years

PICURE: 32. Comparison of age specific pattern of parasite (total: elide positivity, individual species and mixed infections) and 1. falciparum gametocyte rate between females (1) and males ( 2 ) in fever eurveys of 12 villages.

Page. .I59

h / '\.

b- - - - 0 2 - *-- --.--.- - -.- -'-• 1

- P. VIVAX - -

I I I I I

20 40 Age in years

PICURB: 33. Comparison of age specific parasite density index (PDI) between felales (1) and malee (2) in fever surveys of 12 villages in Xoraput.

Page. .I60

though males beyond 20 years generally recorded higher densities

canpared to females.

'Ihe annual fever incidence was 539 and 517 per 1.000 males and

females respectlvoly. Malns hnwovor rncnrrlnd hi 8hr:r AI'I 11 7H.f1/ 1,00111

h e n conpared to females [156.6/1.0001. ?he analysis of age specific

incidence showed that the pattern of incidence was qualitatively

similar for both the sexes but quantitatively males particularly in

adult age classes recorded higher parasite incidence compared to

females (Figure: 3 4 ) .

6 . 4 . 3 . Seasonal changes in fever and parasitaemia:

Analysis of seasonal changes in parasite rate (in all the 12

villages as a whole) showed that the malaria cases started increasing

from June to reach a major peak in July [rainy season), declined

Shdrply in August and started gradually increasing from October to

reach another peak in Deceder (winter season; Figure: 35). Cases of

falciparum and were recorded throughout the year. ?he seasonal

pattern of falciparum was qualitatively similar to total parasite rate

[irrespective of species), since this was the predominant parasite

species. Seasonal changes in P. were not as distinct as in the

case of P. falciparum. Cases of P, malariae were recorded between July

and February (highest proportinn was recordod in Vct~ruary). Cases of E.

ovale were recorded between kcember and February (Table: 41 1. Cases of

Page. ,161

\ "! -

P. FALCIPARUW - -

MIXED INPECTION

20

"B= An, , = m , m

FIGURE: 34. Comparison of age specific patterns of incidence between females ( 1 )

and males (21, in fever surveys of 12 villages.

Page. .I62

60 1. PARASITE (TOTAL) 2. 1. PUCIPARUII

40 -

J P H A I I J J A (Month)

FIGURE: 35. Seaeonal patterns of parasite (total), P. falciparum. P. vivax and g. falciparum gametocyte rates in fever - - surveys in 12 villages in Koraput.

Page. . I63

Table: 41

Seasonal changes i n p a r a s i t e r a t e s i n f eve r surveys i n 1 2 v i l l a g e s of Koraput.

Month No. SPR PFX WR examined ( % I % ( % I

January 324 37.96 28 .70 4 .94 February 206 26 .70 19 .42 1 .94 March 302 24.50 16.56 5.fi3 Apri l 278 26.62 17 .63 6.83 b Y 305 22.62 16.39 4.92 June 333 28.83 16 .52 8 .11 J u l y 626 54.63 46.01 4 . 9 5 August 571 22.77 18 .39 2 . 8 0 Septerrher 608 20.89 15 .63 3 .13 October 422 26.78 18.25 3 .32 Novernber 402 33.08 28 .11 3 .48 December 406 44.58 35.22 3.45

M POR M I X RT PFGR ( 8 1 ( % I ( % I ( 8 )

Tota l 4783 31.72 24.21 4 .31 0 .48 0 .06 2.66 2.97

SPR : S l i d e o o s i t i v i tv r a t e PFR E . fa lc iparum r a i e WR g, = ? a t e EM? P. malar iae r a t e POR P. ovale r a t e M I X RTT M w i n f e c t i o n r a t e PFGR P. fa lc iparum gametocyte r a t e ,

Page. ,164

mixed infect ions were recorded throughout the year and the occurrence

of these were highest in DcrcMber (Table: 41). P. falciparun gamtocyte

rate was lowest in April and a clear peak was observed in January

(Figure: 3 5 ) .

Seasonality of fever and parasite incidence (per 1,000

population) in all the villages was also studied (Figure: 36).

Incidence of fever was lowest in February, which increased gradually

to reach a peak in July and remained more or less stable until

Septmer to decline gradually thereafter. Seasonal pattern of

parasite incidence on the other hand resembled that of parasite rate:

there was a major peak in July and another in Oecerber. The seasonal

pattern of falciparun incidence resehled that of total parasite

incidence. P. % also prevailed throughout the year, its incidence

being highest in July. Incidence of both malarlae and was low and

therefore, no distinct seasonality could be made out (Table: 42).

Seasorlality of infant parasite rate was also analyzed to know

the period of transmission. I t was observed that malaria parasite was

detected in infants throughout the year and there were two distinct

peaks, one in Aug~lst and the other in December (Table: 43). While

falciparm cases were detected throughout the year (highest in Apri 1) ,

viva cases were recorded from May t o August, and from October to - January (highest in August). P. malariae cases were recorded betwen

PICURE: 36. Seasonal changes In fever ( 1 ) . total parasite ( 2 ) P. falclparum ( 3 ) and _P. -x (4) incidence in 12 village^ of Koraput.

Page. . I67

Table: 43

Seasonal changes of parasite rate and density index in infants in fever surveys in 12 villages of Koraput.

m n t h No. examined

- - -

January 19 February 11 March 8 Apri 1 6 May 18 June 2 1 July 20 August 26 Septerrber 18 October 22 November 21 December 17

SPR ( % )

47.37 27.27 25.00 33.33 16.67 28.57 20.00 50.00 22.22 27.27 33.33 52.94

PFR ( % 1

10.53 18.18 25 .OO 33.33 11.11 14.29 10.00 30.77 22.22

9.09 23.81 23.53

PFGR [ % )

50.00 50.00

0.00 0.00 0.00

33.33 0.00

25.00 0.00

50.00 20.00

0.00

TOTAL 207 32.85 18.36 8.70 2.42 0.48 18.42

sPR : Slide positivity rate PFR : P. falciparum rate PVR : g. rate FMR : P. malariae rate mt : r . ovalo rate PFGR: P. falciparum gametocyte rate

Page. .I68

Novmbr and February, their occurrence being highest in January. One

case of P. was recorded in Decewer. The pattern of seasonal

incidence of parasitaemia in infants generally reserrbled that of infant

parasite rate (Figure: 37; Table: 44).

6.4.4. Spatial distribution of parasitaemia:

The annual parasite rate was compared between the four groups of

villages in two geographic zones (Table: 45). Tophill villages in both

zones recorded higher parasite rates (above 50%) compared to the other

types of villages. Though the tophill village in Malkangiri recorded a

higher parasite rate 159.81%) compared those in Jeypore (51.2%), the

difference was not statistically significant ( P >0.051. The foothill

villages in both zones recorded slrnilar parasites rates: 43.9% and

42 .2% in Jeypore and blalkangiri respectively ( P >0.05). The villages

in plains in Jeypore recorded significantly higher parasite rate

118.9%) compared to that 113.8%) in Malkangiri zone ( P t0.051. The

riverine village in Malkangiri recorded a very high parasite rate

(45.0%) compared to those in Jeypore (17.0%) and the difference between

the zones was statistically significant ( P c0.05). The annual

falciparum and rates were higher in the tophill villages compared

to the other groups of villages in both the zones. Whlle P. malariae

was detected in all the groups of villages in both zones, P, &was

detected only in the top and foothill villages in Jeypore. Mixed

infections were recorded in a1 1 groups of villages and their occurrence

Page. .I69

J P H A n s J A S O N D (Month)

PICURE: 37. Seaeonal patterns of fever (1). total Parasite (2). P. falciparum (3) and g. rival ( 4 ) incidence in in- - fante in fever surveys in 12 villages of Koraput.

Page. ,172

was highest in the tophill villages in both zones. P. falciparm

gmtocyte rate was higher in all the groups of villages in J w o r e

canpared to Malkangiri zone. Tophill villages recorded the highest

falciparm garnetocyte rates in respective zones .

Parasite rate in 2-9 year children is used to classify areas

under degrees of endmici ty (Bruce-Chwat t , 1985 ; Pampana. 1969). '1he

annual parasite rates in this age class indicated that, while the

tophill and foot hill villages in .Jeypore zone were hyperendmic

[parasite rates of 73.3% and 50.9% respectively), the riverine villages

were mesoendmic (parasite rate 11.7%1 and the plain villages were

hypoendmic (parasi te rate 6.6%). In Malkangiri zone, though the

parasite rates [in this age class1 were different compared to Jeypore,

the levels of endemicity were similar. The tophill and foothill

villages were hyperendemic (parasite rates of 59.4% and 58.3%

respectively), the riverine village was mesoendemic (parasite rate of

50%) and the plain village was hypoendemic (parasite rate of 9.6%).

The incidence [per 1,000 population) of fever and parasite in

different groups of villages in two zones are shown in Table: 46.

Highest incidence of fever and falciparum infection was recorded in the

foothill village in Malkangirl. Parasite incidence was the highest in

the tophill village in the same zone. Incidence of vivax, malariae and

ovale infections was highest in tophill villages of Jeypore zone. The -

incidence of mixed infection was the highest in the tophill village in

Malkangiri.

The age specific parasite rates in the different groups of

villages are canpard in Figure: 38. In the tophill villages in Jeypore

zone, the infant par~si te rate was fifi.08, anrl i t incrt:ils~~d tn rc:ach a

p a k level of 81.5% in 1-2 year old children and declined sharply

thereafter in adult age classes. In foothill villages the infant

parasite rate was 21.0%, and increased to reach a peak level of 53.7%

in 4-9 year age class (a shift of peak age cmpared to tophill

villages) and declined gradually thereafter (Figure: 38 A ) . The

difference in the age prevalence curves between the two villages is

distinct. The patterns for the riverine and plain villages in Jeypore

zone w r e similar (Figure: 38 8 ) . The parasite rates increased

gradually in childhood to reach peak levels in juveniles and young

adult age classes (the peak for riverine villages was 36.8% in 15-20

year age class and that for plain villages was 37.2% in 20-30 years age

class) and declined gradually in older age classes (a minimal rise was

also evident in old age class of beyond 50 years).

In the tophill village in Malkangiri, the peak parasite rate was

in the 1-2 year age class (as in the case of tophill villages in

Jeypore zone) and it declined thereafter to stabilize in adult age

clpsses (Figure: 38 C ) . The age specific patterns of parasite rate in

the foothill and the riverine villages (Figure: 38D) w r e similar and

reflected a situation midway betwen top and foothill v!!lages in

M L K A N C I R I *

e 60

M L K M C I R I

40

30

.- Age in years

PICURE: 3R. Comparison of age specific patterns of parasite rate in tophill (1). foothill (21, riverine (3) and plain ( 4 ) villages in the two zones in lever sruveye of loraput.

& tbe number of cases with fever was low, wider class intervals were selected.

Jeypore zone. In the plain village in Malkangiri zone, the peak

prevalence was observd in 9-15 year age class (Figure: 38D1, following

which i t declined gradually in adults. Adults recorded higk~er parasite

prevalence canpared to young children as was also observed in the plain

villages in Jeypore.

Comparison of the age specific incidence in the different groups

of villages in the two zones was also done (Figures: 39 6 40). The

patterns of parasite incidence in the tophill villages in both the

zones and the riverine village in Malkangiri zone were qualitatively

similar: the peak incidence was in toddlers (children 1-2 years old).

following which there was a sharp decline in adult age classes.

Quantitatively however, tophill villages in Jeypore zone recorded

higher incidence ccmpared to the others. In the foothill villages in

both the zones, the parasite incidence increased from infant level to

reach a peak in juveniles (4-9 year old: note the shift in peak age

class cqared to the tophill villages), following which, i t gradually

declined to r m i n more or less stable in the adult age classes. In the

plain and riverine villages in Jeypore zone, the level of parasite

incidence in adults was higher canpard to children. The age specific

pattern of parasite incidence was at a low level in the plain village

in Malkangiri and i t was not distinct. (Note that the Y scale for the

figures are different, since i t was not possible to present all with

sant, scale).

It was also observed that children below 9 years suffered m r e

than one attack of malaria annually (recording incidence of 1,000 to

Page. .I77

TOPHILL

Age in yearn

FIGURE: 39.1. Patterns of age specific incidence of fever (11, total parasite ( 2 ) . z. falciparun ( 3 ) . P. vivax ( 4 ) and P. malariae (5) in top- hill and foothill villages in Jeypore zone.

(example 1 in "Y" axis = 1,000)

Page. .I78

H

Age i n years

PICURB: 39.2. Patterns of age spec i f i c incidence of fever (1 ) . to ta l parasite ( 2 ) . P. faleiparum ( 3 ) . P. vivax ( 4 ) and E. malariae ( 5 ) i n plain and riverine v i l l ages i n Jeypore zone.

Page. . I 7 9

TOPHILL

1.0

'1

- -.----,-- --v , ' 0.0 . 0 20 40 60 0 20 40 60

Age i n years

PICURB: 40.1. Patterm of age spec i f i c incidence of fever (1) total parasite ( z ) , P. falciparum ( 3 ) . P. vivax ( 4 1 and P. nalariae (5) in tophil l and - - - - foo th i l l v i l lages i n Malkangiri zone.

*(example 1 i n "Y" axle = 1,000)

PLAIN

0.5 l 0 L 2

PLAIN

0 .1 I- ,, . &&<%g::&:- -. - - - 7-8-;e;

0 20 11 0 60 i n years

PIOURE: 40.2. Patterns of age spec i f i c incidence of fever (11, to ta l parasite (21, P . falciparum ( 3 1 , P. vivax ( 4 ) and P. malariae ( 5 ) i n plain and riverine v i l l ages i n llaltangiri zone.

(example 1 i n "Yo a x i s = 1,000)

3,000/1,000 children) in the first group of villages 1 tophill in both

zones and riverine in Malkangiri), which reflected the high degree of

malaria transmission. The other observation from the above patterns of

incidence is that, in the villages with high degree of transmission

(tophill in both zones and riverine in Malkangiri) the separation

b t w e n the age profiles of fever and parasite incidence was relatively

narrow and there was a striking resemblance in the patterns of both

[Figures: 39.1 A , 40.1 A, 40.2 G). n i s was not so in the other groups

of villages. Thus the fever incidence in the 'first group of villages

1 tophill in both zones and riverine in Malkangiri) could reflect the

pattern of malaria incidence, while i t was not so in the other groups

of villages. In fact, the wide separation between fever and parasite

incidence in plain villages (Figures: 39.2 E, 40.2 E ) indicated that

most cases of fever in these villages are due to causes other than

malaria.

The age specific patterns of falciparun density index in

different groups of villages is s h m in Figure: 41. In the tophill

villagas in Jeypore zone and the foothill villages in both the zones,

the parasite density levels were higher in children compared to adults

(marked in f o m r cqared to latter). On the other hand, in the plain

and riverine villages in Jeypore zonqadults generally recorded higher

density cmared to children betwen 4-15 years. In the other villages

the patterns were not very distinct.

JKYPORB

" 0

IULXANCIRI*

2

0 - 1

0 20 4 0 60 Age i n years

FIGURE: 4 1 . Comparison o f pat terns o f age a p e c i f i c P. falciparum p a r a s i t e d e n s i t y index i n the t o p h i l l ( 1 ) . f o o t h i l l (2), r i v e r i n e ( 3 ) and p l a i n ( 4 ) v i l l a g e s i n f e v e r sruveys i n two zones of Koraput.

As t h e number o f c a s e s wi th f e v e r was low, wider c l a s s I n t e r v a l s were s e l e c t e d .

8r

Seasonality of parasi to rates in different groups of villages

was also canpard. In Jeypore zone, all four groups of villages

recorded the major peak during rainy season in July (the peak was sharp

in rivtrrine and foot hill villages) and a second peak was observd

during winter [Cecmber - January). The seasonality of P, falciparm

generally resMnbled the pattern for total parasite rate. Peak

rate was observed between March and June (March in foott~ill, April in

plain, and, June in tophill and riverine) prior to falciparum peak

(Figure: 42). The seasonality of malaria in Malkangin villages was

different (Figure: 43). In top and foot hill villages the peak was in

winter (October - January). However, there was s m d~fference in their

seasonal patterns. While in the tophill village no malaria case was

recorded between February and Apri 1 , in the foothill vi 1 lage cases were

recorded throughout the year. The pattern in the tophill village was

not distinct, possibly due to the variations in sample size (depending

on the number of fever cases) in different months. In the plain

village, two distinct peaks, a major one in Deceher and the other in

March were observed. The seasonality in thy riverine village was not

distinct, though cases were recorded throughout the year.

Seasonality of parasite incidence in the different groups of

villages was also canpared (Figures: 44 6 45). In all the groups of

villages in Jeypore zone, the seasonality of malaria incidence

readled that of parasite rate. While the major peak in top and

foothill villages was in July, i t was in Septtrnber in plain and

Page. .I84

J P I I A I I J J A S O N D J P M A M J J A S O N D (Month) (Month)

PIGURU: 42. Comparison of seasonal patterns of to ta l parasite (11, !. s- par- ( 2 ) , 1. ( 3 ) and P . malariae ( 4 ) rates between four - group8 of v i l l ages i n Jeypore zone.

PICURB: 43. Comparison of seasonal patterns of t o t a l parasite (11, P. f a l c i - parum ( 2 ) . 11. ( 3 ) and E. m l a r i a e ( 4 ) rates between four - di f f erent groups o f v i l l a g e s i n llalkangiri zone.

Page. ,186

J P X A M J J A S O N D J P M A M J J A S O N D (Nonth1 (Month)

PICURB: 44. Comparison of seasonal patterns o f fever (1). to ta l parasite ( 2 ) . P. Palciparum ( 3 ) and P. ( 4 ) incidence i n 4 different groups - - of v i l l ages i n Jeypore zone.

3 a

0

,a 30

O. 1 no k 60 Ci

0 50 $ 30 0

8 3 0 0

J F M A M J J A S O N D J F M A M J J A S O N D (Month) (Month)

PICURB: 45. Comparison of seasonal patterns of fever (1 ) . total parasite ( 2 ) . P. falciparum (3) and P. vivax ( 4 ) incidence in 4 different groups - - of villages in Mlkangiri zone.

riverine villages. In Melkangiri, the seasonality of parasite incidence

was distinct unlike the seasonality of parasite rate (compare Figures:

43 6 45). In the tophill village, twa distinct peaks were observed: one

in June (sharp) and the other in January. A distinct peak was observed

in March in the plain village and in the foothill village, parasite

incidence increased from May onwards to reach peak levels between

Novder and January. The seasonal pat tern of parasite incidence in the

riverine village showed the major peak in October.

Seasonality of parasite rate/incidence was also studied for

individual villages in both the zones. I t was observed that the

patterns varied betwen the villages, even within the same ecotype/zone

(Figures: 46 6 4 7 ) .

6.4.5. Incidence of fever and parasitaemia in different

c m u n i ties:

The data collected in the initial fever survey in the22

villages (1987) was further analyzed for incidence of fever and

parasi tamia in the different ccmnunities. The results indicated that

both fever and parasite incidence varied widely in the different

tribal/ other cmnities (Table: 47). Both fever and parasite

incidence were higher in Cmothios and Paikas canpared to Porojas.

100

5 0 MLKANCIRI JBYPORE 1

0 JEYPORB 2

FOOTHILL

A

80

40 JBYPORB 1 JEYPORB 2

O MALKAMCIRI

- U

6 0

4 0 20

*AUANCIRI

j 0 JBYPORE 1 JBYPORE 2

L

PLAIN

A

60

40 JBYPORB 1

20 JBYPORB 2

0 MALKANCIHI

J P l A l J J A S O N d ( M o n t h )

PICURB: 46. C o m p a r i s o n o f s e a a o n a l p a t t e r n o f p a r a s i t e r a t e i n t h e i n d i v i d u a l v i l l a g e s (1 v i l l a g e i n m l k a n g i r i z o n e a n d 2 v i l l a g e s i n J e y p o r e zone , i n e a c h o f t he g r o u p s ) i n f e v e r s u r v e y s o f KoSaPUt.

{,The o r d e r o f t h e v i l l a g e s i n t h e 4 g r o u p s h a v e b e e n ' m ~ . r * e l ~ ~ o t t d l l ' l c ~ ~ c ~ ~ l l y Lor c l a t . l L y )

FOOTHILL

r-- -1 u

2 100

g MALKANCIRI 0 50 JEYPORE 2

f 0 JEYPORE 1

MALKANGIRI JEYPORE 1

20

10 JEYPORE 1 JBYPORE 2 lALKANGlRI

0

J P M A M J J A S O N D (Month)

PICURE: 47. Comparison of seasonal pattern of parasite incidence in the individual villages (1 village in Nalkangiri and 2 villages in Jeypore zone, in each of the groups) in fever survey8 of Koraput.

(The order of the villages in the I groups have been arranged differently for clarity)

Page.. 191

Table: 47

Caparison of fever and parasite incidence among different tribes4 camunities in fever surveys in 22 villages in Koraput (19871.

Tribe/ Population Incidence per 1,000 population PFGR cannunity size ( 8 )

Fever Parasite

Age in years

Poroja 1 4 9 1 2847 102 .0 131.7 34.2 43.2 D M b o 920 1744 130 .4 1 8 2 . 9 37.0 51.6 Chnathio 3 9 1 678 496.2 697.6 104.9 182.9 Pa i ka 1 0 1 248 386.1 467.7 138.6 197 .6 Tant i 116 210 336.2 261.9 94.8 52.4 Mali 179 312 217.9 333.3 50.3 80.1

PFGR: g. falciparm gametocyte rate

Page. ,192

6.4.6. Actual coverage of population in the fever surveys:

In the 4 villages (one of each type) the actual presence or

absence of individuals in the village at the time of surveillance was

mnitored (for 10 to 12 mnths). On an average, the total absentees per

visit (fortnightly) ranged between 28.0% of population in the village

in plain8 to 56.09 of population in the tophill village (Table: 481.

Approximately 5.6% of the population had left the village temporarily

for few days due to various reasons. Of the absentees a majority

(81.2%) had left the village for their daily work and earning. The

exact reasons for the high absentee rate in the tophill village is not

known. Since the villages are located in remte areas, people tend to

leave the village earlier compared to other villages for daily work.

The other possibility is the delayed arrival of the surveillance

workers in these villages due to practical constraints in reaching the

villages (long distance and poor cmunication facilities].

nough no seriously il l or febrile person was expected to have

left the village during the survey, i t was possible that some

individuals who were absent had febrile at tacks in between visits of

the surveillance worker or had mild illness and early manifestations of

malaria and these persons were not covered under surveillance as they

were not available at the time of house visit.

Page. .I94

6.4.7. Relationship between clinical presentations and

parasi t aemia:

The relationship between individual clinical manifestations and

parasitaemia was also studied. For this purpose the parasite rate in

persons having only single syrrptcm was analyzed (Table: 491, Though

persons with fever or vmiting recorded relatively higher parasite

rates, parasitaemia was detected in persons with any of the synptoms.

The P. falciparun density index was also high for cases with vomiting

and fever (Table: 49). The mean duration of fever was 4.37 days.

Analysis of symptoms apart from fever showed that, while there was

significant association between vomiting, head~che and diarrhoea with 2

P. falciparun parasi taemia (vmi ting: X ~ 4 2 . 3 3 , I' = 0.(11)1); headache: -2 2 X = 5.81; P = 0.016; diarrhoea: X = 4.34, P = 0.0371, other

2 symptoms had a poor association (nausea: X = 0.01, P = 0.931; body

2 ache X = 0.33. P = 0.566).

Clinical diagnosis prior to blood smear examination was made in

888 persons. Of the 327 persons diagnosed to be suffering from typical

malarial attack, 140 (42.8%) shaved peripheral blood parasltaemia. Of

the rest 561 persons, who were clinically diagnosed to be suffering

f r m illnesses other than malaria, 66 (11.76%) had parasitaemia [Table:

50). The parasite rates in these two groups were significantly

different [P <0.05).

Page. .I95

Table: 49

Canparison of parasite rate in patients with different clinical manifestations.

Clinical No. No. Parasite PDI Pf manifestations* examined +ve rate ( $ 1

Fever Headache Diarrohea Body ache Nausea Vomiting

PDI Pf: Parasite density index in P.falciparwn cases * Only persons having single manifestation have bean

considered

Table: 50

Comparison of parasite rate in cases with different clinical diagnosis.

Clinical diagnosis

No. No. +ve for Parasite examined parasite rate ( 8 1

Malaria 327 140 4 2 . 8

Other diseases

Respiratory infection 253 25 9.9 Skin diseases 181 17 9 . 4 Malnutrition 5 0 11 22.0 Gastroenteritis 30 4 1 3 . 3 Arthralgia 32 3 9.4 Viral fever 15 6 40.0

Total 888 206 23.2

Page. .I97

6.5. DISCUSSION:

Ihe results of the year round fever survey in the 22 villages in

Jeypore zone indicated that all were endemic for malaria. Caparison of

results showed that the surveillance under the national programne was

effective in detecting only about 55% of malaria cases (since the W1

in present study was 89.1 as against 49.5 per 1,000 population under

the national progrm). Problems relating to efficiency of case

detection under the nat iondl prngrarmne is well hr~uwn ISharmna g.,

1983; Choudhury, 1984; Anonpus, 1985a). This appears to be one of the

most important factors responsible for the persistence of malaria in

this district (see chapter: 10).

The results in the sor:ond year of the study revealed the

presence of all four human malarial parasites in the locality. Hitherto

there was no scientific evidence of presence of P. ovale in any part of

Irvlia (Choudhury, 1985b). Neither this parasite nor P. malariae (which

is known to be prevalent in this locality from early part of the

century: Perry, 1914; Senior White, 1937a; Senior White, 1938) have

been recorded under the national p r o g r m . The importance of P.

malariae has been discussed earlier (chapter 5.4). Endemic foci of P.

ovale are restricted mostly to parts of Africa (Garnham, 1966; Onori,

1967; Armstrong, 1969; hblineaw and Gramiccia, 1980), though this has

been detected occasionally in other parts of the world (Millan and

Kelly, 1967; Cadigan and Dssowi tz, 1969; Scmboon and Sivasomboon, 1983;

Sher g g., 1988: Storey g g., 1989). This parasite is known to be

highly susceptible to cheimtherapy (Loban and Polozok, 1985). The

presence of this parasite in remte tophill villages indicated the

inadequacy of case detection and treatment in these areas. Presence of

all the four h m n malarial parasites together with several vectors (9

known vectors are prevalent in the locality: VCRC annual report; 1989)

indicated the high malariousness of the area.

Presence of infants wi th parasi taelnia thrtnlghnut the year

indicated perennial transmission. The results also indicated the

possibility of Lwo pcnh Irdnsi~iissio~~ [~crlr~rls: OIII: 1 1 1 1 111wi11y 1110 o~~sc:l

of rains during July - August and another in winter, between Noverber and January.

Analysis of annual fever survey data confirmed the spatial

heterogeneity of malaria in the locality. The problem of malaria varied

k,th qualitatively and quantitatively, not only between the two

physiographic zones but also between ecotypes of villages within the

zones. The patterns of age specific parasite rate and incidence in the

different groups of vil lagcs indicated difference iii degrees of

transmission (Viswanathan, 1!151: Mol ineaux, I I I R H 1. 'lhose pat terns in

Koraput district could be classified into three types (see Figures: 38,

39 and 40):

(1). The pattern in tophill villages in both zones and riverine

village in Malkangiri indicated high degree of transmission

(since parasite rates in children below 5 years was very high)

and high level of acquired i m n i ty ( the sharp decline in

parasite rate in adults is indicative of this).

(ii). The other eno of the spectrum is represented by the pattern in

plain villages in both zones and riverine village in Jeypore

zone, where the transmission was relatively at a lower level

(gradual rise in parasite rate in childhood to reach peak levels

in young adolescent/adult age classes, depending probably on the

degree of exposure).

(iii). In betwen the above two extrms lies the pattern observed in

foothill villages in both zones, where the transmission was

moderate (resulting in shifting of peak age to 4-9 years) and

level of acquired imnity was lower canpared to tophills (since

adult parasite rates were relatively higher].

Viswanathan (19511 had classified endmicities according to the

patterns of age specific parasite rate. According to his classification

the pattern in tophill village in Jeypore zone indicated holoendmic

situation and that in Malkangiri indicated hyperendemic situation.

Foothill villages in both zones and riverine village in Malkangiri

S h m d a pattern which indicated a highly endemic situation. The

pattern in all other groups of villages indicated mesoendtmic

situation. m e thtrorot lcal pat turns prr~jrosr:[l by Vlswanalhan arrl

presented for camparison [Figure: 4 8 ) .

Page. .ZOO

0 5 10 15 Age in years

PIGURB: 48. Patterns of age specific parasite prevalence to illustrate the transmission at different levels of endemicity: hypoendemic (1). mesoendemic ( 2 ) . highly endemic (3). hyperendemic ( 4 ) . holoendemic (5) and superendemic (6) situation (as per Visranathan. 1951).

There was no agreement between endmicities of different groups

of villages as determined by mass blood surveys (chapter: 5 . 3 . 4 : Table:

191 and fewr surveys. Inclusion of asyqtamtic individuals in mass

survey unlike in fever survey is possibly responsible for this

difference. Again there was no complete agreement in the degrees of

endemicities in different groups of villages by child spleen and

paras1 te rates (Chapter 5 . 3 . 4 ) . These findings highlight the

difficulties in interpretation of results obtained by different

surveys. Problems in classifying areas under different degrees of

endemicities are known (Iyengar and Sur, 1929: Viswanathan. 1951;

Pampana, 1969; Bruce-Chwatt , 1985).

The seasonality of malaria also clearly varied in the two

physiographic zones and the four ecotypes of villages. ?his showed the

necessity for planning of control measures separately for different

localities. The time and frequency of residual insecticide spray have

to be adjusted according to transmission seasons. The wide separation

between the profiles of fever and parasite incidence particularly in

plain villages indicated that pres~mptive treatment CII all tcver caries

is not warranted in these villages. The insistence of imparting

presunptive treatment to all febrile cases leads to over consmption of

antimalarials (Najera, 1989).

Unlike in the case of mass blood surveys (chapter: 5.3.31, there

was no significant difference in parasite rates between the sexes in

the annual fever survey. While the former was a random survey, the

latter was a biased survey for fever cases. Whether the difference is

due to this reason or othenvise is not known.

Results of mass blood survey had shown high prevalence of

parasi taemia among the aborigine tribals (Bondas and Porojas; see

chapter:5.3.5). Bondas were not included in the fever survey. Porojas

however, recorded low parasite incidence when compared to others in the

fever survey. This again could be due to the difference in sampling in

two surveys. I t is possible that many Porojas circulated parasite, but

were asymptanatic and they were detected only in mass survey but not in

fever survey.

Following the failure of eradication programnes, i t has been

advocated to reconsider malaria as another disease entity particularly

in areas where the resources do not permit ef Sect ive surveillance

(WD, 1986a; Hays, 1989, bblineaux, 1989). In such situation, one has to

depend on the clinical findings for malaria case rietr:ction. The present

study revealed that the parasite rate in cases presenting with symptms

other than fever was also high in Koraput. Further, the manifestations

due to P. falcipsrum may be varied and typical malarial fever

periodicity takes time to establish (Bruce-Chwatt , 1985; Loban and

Polozok, 1985), hence the clinical diagnosis can be improved by looking

for fever with other associated symptms. A chination of

manifestations such as fever, headache and vmiting seem to be a useful

indicator of falciparun malaria. The type of manifestation could also

be dependent on the innune status of individuals as suggested by the

difference in parasite density index in different manifestatibns.

Relationship between parasite density and clinical manifestations is

well known (Sinton g g.. 1931: Pazzaglia and Wot~dwarrl. 11102: I.oban

and Polozok. 1985; Richards etg. , 1988a).

API has been used as a yard stick for deciding the nature of

control measures under the national progranane (Pat tanayak and Roy,

1980; S h a m , 1984a; also chapter: 4). The present study revealed that

a large proportion of the population was not available at the time of

survey. It was possible that some of them may have had mild illness (in

spite of which they go out to earn their livelihnod due to poverty) and

these persons were missed. Ibis not only lowered the reliability of API

as an indicator of malaria, but also could have resulted in

accmlation of parasite load in the comnity favouring the

persistence of the problem.