ICMR BULLETIN VOL. 28-No.-3-MARCH-1998
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- ICMR BULLETIN VOL. 28-No.-3-MARCH-1998
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Vol. 28, No. 3
March, 1998
MALARIA SITUATION IN NORTH-EASTERN REGION OF INDIA
Malaria is one of the major public health problems of
the north-eastern (NE) states of India. The disease is un
evenly distributed over the region showing distinct epide
miological paradigms attributable to eco-geo’graphic, eth
nic arid socio-cultural diversity. Malaria is found all over
the north-eastern region except for areas above 5000 ft
from MSL1,2. Stable malaria with preponderance of Plas
modiumfalciparum infection (60-80%) is the main char
acteristic of the disease pattern in the north-eastern region'.
Though the population of the NE region is 3.7% of the
Indian population, this region contributed 8 to 12% of ma
laria positives, 10 to 20% of P.falciparum (PF) infections
and 13 to 41% of deaths due to malaria in the country’s
average between 1991-1995. After the introduction of the
National Malaria Eradication Programme (NMEP) in 1958,
a dramatic reduction of malaria occurred in all malarious
areas of the country which was, however, relatively less
marked in the NE region2. This was evidenced by the re
tention of 50% area (9.29 NMEP units) in the NE region
under the attack phase of NMEP compared to 11% in the
rest of the country in 1968’’3. After 1965, a resurgence of
malaria occurred in various parts of the country and the
NE region was no exception. Large tracts of this region
being hilly, forested, relatively inaccessible with poor com
munication and inadequate infrastructure, made control of
malaria logistically difficult. The factor which further com
pounded the problem of malaria resurgence in the north
east was the development of chloroquine resistance in P.
falciparum in Assam4. To appreciate the malaria situation
in the NE region in a better way an attempt has been made
in this article to provide a profile of malaria in the region
briefly covering various elements of disease transmission.
Topography
The NE region of India, comprising 7 states viz.
Arunachal Pradesh, Assam, Manipur, Mizoram,
Meghalaya, Nagaland and Tripura, is situated between
22°04' and29°31' N and 89°48' and 97°25' E covering an
area of2,55,128 km2. The region has international borders
on the north (with China), east (Myanmar)'and south
(Bangladesh). In the west it is contiguous with West Ben
gal. The NE region contributes 7.8% of the total land mass
of the country. About 45% of the north-east is covered
with tropical evergreen rain forest.
The region can be divided into 3 major geographical
entities viz. the Himalayas, the Indo-Brahmaputra basin
along with the Barak, Imphal and Tripura valleys (plains)
and hill ranges bordering Myanmar and Bangladesh (north
eastern plateau). The northern Himalayan ranges are low
and usually do not exceed 1850 m in height. The areas
above 5000 ft MSL bordering China are free from malaria
but the foothills and adjacent hills are highly malarious.
The Indo-Brahmaputra basin (alluvial plain) is sandwiched
between the Himalaya in the north and the hill ranges ex
tending from Myanmar in the east to the Garo hills in the
south. This region along with the Barak, Imphal and Tripura
valleys has variable endemicity of malaria. The hill ranges
Division of Publication & Information, ICMR, New Delhi -110029
along the Indo-Myanmar border, lying in the north-south
direction, extend up to the Indo-Brahmaputra basin and
are hyper-endemic for malaria. The hill ranges bordering
Bangladesh in the south (lie east-west) which include the
Naga, Mizo, North Cachar, Cachar, Karbi, Jaintia, Khasi
and Garo hills have large areas with hyper- to holo
endemic malaria.
Climate
The climate of the region is conducive for prolonged
malaria transmission. The south-west monsoon brings
heavy rain fall to Assam and the adjoining states. Though
the main rainy season is between June and September, rains
occur more or less through out the year. The average num
ber of rainy days is 200-250. The characteristic of rain fall
in the NE region is its uneven precipitation. While
Cherrapunji-Mowsynram region (Meghalaya) gets an
annual rain fall of 11,500 mm, the Manipur valley in the
same geographical zone receives a rain fall of 1000 mm.
Most of the areas except the north-eastern plateau receive
more than 2000 mm rain fall.
2,53,000 labourers engaged in 46 commissioned projects
in the north-east, 70,900 (28%) were seasonal labourers
who had immigrated from other parts of the country5. Large
scale population movement, resulting in the introduction
of newer strains of malaria parasite and dissemination of
drug, resistant strains is responsible for accelerated
malaria transmission in the region.
The economy of the NE region is primarily agricul
ture based. In the plains mainly rice is grown by wet culti
vation whereas in hilly forested areas the inhabitants;prac
tice shifting (Jhum) cultivation. It is estimated that 18.4%
area in the north-east is under Jhum cultivation6. The cli
mate in this region is suitable for growing tea and most of
the highlands, plains and foothills are utilised for tea plan
tations. Most tea gardens are located in Assam, Arunachal
Pradesh and Tripura7. Oil, coal and timber are the other
important industries of this region.
Vectors of Malaria
The region can be divided into three major isothermic
zones. In the greater and lesser Himalayas, the tempera
ture ranges between -20°C in winter to 15 to 20°C in sum
mer. The northern part, except the greater and lesser
Himalayas, along with the sub Himalayan areas lie within
the 4°C January to 21 °C July isotherms. The IndoBrahamaputra basin lies between the 21°C January to 30°C
July isotherms. The relative humidity of the region is more
than 60% throughout the year.
Due to its peculiar climate, topography and terrain,
the NE region is rich in flora and fauna. As such 130 spe
cies (37 anophelines and 93 culicines) of mosquitoes be
longing to 12 genera have been recorded in this region8.
Malaria in the NE region is primarily maintained by three
major vector species viz. Anopheles dirus, An. minimus
and An. fluviatilis*. In the past natural infection have been
found in An. philippinensis, An. annularis. An. maculatus
var. willmorei (=An. willmorei) and in An. culicifacies™
in NE region, however, they are not considered of much
importance.
Demography
An. dirus
TheNE region has a population of3,14,00,855 (1991
census). The decadal (1981-91) growth rate of the region
was 39.7% which ranged from 23.6% in Assam to 56.9%
in Nagaland. The population density in the north-east is
117/km2. This also shows a wide variation of 10/km2 in
Arunachal Pradesh to 284/km2 in Assam. This region is
inhabited by many ethnic and cultural subgroups whose
beliefs, culture, life-styles and occupational needs have
direct bearing on the transmission of vector-borne disease.
In the NE region, 25.2% of the total population is tribal
with varying ethnicity. The tribals generally inhabit the
forest and forest fringe areas. There is a large scale move
ment of people from outside and within the NE states for
agriculture, project work and forest activities. Even within
the same state sometimes the whole village shifts to
another site in search of newer agricultural and forest land.
Besides the permanently settled, there is a large floating
population consisting of seasonal labourers from Orissa,
Bihar and West Bengal. Studies have shown that of the
An. dirus is regarded as the most important vector
of malaria in the entire South-East Asia region. It is
distributed in the wet forest areas in north-eastern India,
western ghats in south-western peninsular India and the
Andaman Islands. It is a complex of at least 7 sibling
species provisionally designated as dirus A, B, C, D, E, F
and takasagoensis with species ‘D’ reported to occur in
north-east India11. In India, An. dirus was first incrimi
nated in the Digboi area of Assam12 and subsequently from
different NE states13’15. It is basically a forest breeder and
breeds mainly in temporary, shady/partly shady ground
pools. Biting by An. dirus which occurs throughout the
night is predominant between 2100 h and 0300 h. This
mosquito feeds both indoors and outdoors and has a pro
pensity to feed more on humans with >90% anthropophilic
index. During the day females take shelter in the forests. It
is a hygrophilic species, able to. adapt to changing
environmental conditions and demonstrates the pheno
menon of “annual pulsation” wherein its “mother foci” in
22
0
the deep forests expand to the peripheral “secondary foci”
during the rainy season and again retreat tb the deep for
ests during the dry season16. This annual pulsation explains
the high density of this species in the monsoon months
(June-October) and extremely low density in the dry cool
period (December-March). It has been reported that An.
dirus is associated with the spread of chloroquine resis
tant P. falciparum strains17.
An. minimus
>
"
It was once considered as the most important vector
of malaria in the entire sub-Himalayan belt. Subsequent
to the large scale application of DDT under the NMEP
this species disappeared from its area of influence9, 13. How
ever, during the eighties An. minimus was again recorded
in the NE region and incriminated as the vector in
Assam18,19, Arunachal Pradesh20, Nagaland21 and
Mizoram14. It is a species of the hills and foothills occupy
ing ecotone zones closer to the forests. It breeds mostly in
slow running streams with grassy margins. An. minimus is
prevalent throughout the year with higher densities between
March and August. It is an endophilic, endophagic spe
cies with high anthropophilic habits. It usually feeds
throughout the night with pronounced feeding between
2100 h and 0400 h. It prefers to rest indoors on the lower
half of the walls and its distribution is usually patchy in
the village with some houses being preferred for resting.
An. minimus is highly susceptible to the residual insecticides22.
An. fluviatilis
It is essentially a species of the hills and foothills but
is also found in irrigated plain areas. Though recorded from
most of the north-east states, it was earlier disregarded as
a vector due to the non detection of natural infection. It is
a complex of 3 sibling species provisionally designated
as fluviatilis S, T and U23. Amongst these, species S is
predominantly anthropophagic in contrast to T and U
species24 which are exclusively or primarily zoophagic.
Deforestation in order to retrieve forest land, is possibly
responsible for the establishment ofAn.fluviatilis in large
tracts of the north-east. As a result most of the ecotone
zones are under the influence of An. minimus as well as
An. fluviatilis with the increased period of transmission
and seasonal overlapping16. It is a clear water breeder
normally found in streams, irrigation^! channels with
grassy edges and perceptible flow of water. An. fluviatilis
is basically a post monsoon species prevalent between
November and July with peak densities in March to April.
It prefers to rest indoors during the day. Though it bite
throughout the night, feeding is mainly before midnight.
It is susceptible to commonly used residual insecticides18.
Epidemiological Profile of Malaria
Malaria endemicity in the NE region showed wide
variations between 1961 and 1995 (Fig. 1). During this
period the proportion of P. falciparum (Pf%) ranged from
16.8 to 70.6 and slide positive rate (SPR) from 0.96 to
Pf%
Fig. 1. Epidemiological situation in NE region of India (1961-95)
SPR: Slide positive rate; SfR: Slide falciparum rate; Pf %: P. falciparum percentage
23
10.2%. All indicators of malaria incidence showed the low
est values in 1965 and 1976 was the yearof maximum
incidence. The period between 1961 and 1995 can be di
vided into four distinct phases to understand the fluctua
tions in epidemiological situation of the region.
decline in malaria during this period was mainly ofP. vivax
cases and Pf percentage actually showed a rising trend.
Another feature of this phase was the occurrence of wide
spread epidemics5 in different parts of Assam and Tripura
during 1986.
Phase I (1961-1965)
Phase IV (1991-1995)
Surveillance to detect malaria cases was instituted in
1961 under the NMEP. During this phase malaria trans
mission was successfully curtailed resulting in a decline
of SPR from 1.2 to 0.96, slide falciparum rate (SfR) from
0.64 to 0.16 and there were no deaths. DDT pressure re
sulted in geographical contraction of malaria in the NE
region.
This period can be called the phase of second resur
gence marked by a rapid increase in malaria incidence as
well as geographical expansion of the disease. Malaria and
Pf incidence increased by 42 and 177% respectively in
1995 as compared to 1991. The maximum number of
deaths also occurred during this phase (Fig. 2).
Phase II (1966-1976)
Achievements of the phase I began to fade due to the
resurgence and geographical expansion of malaria.
During this period, the hard core areas (forest/hil 1) resisted
the efforts to control malaria. The incidence of malaria
rose from 12,412 in 1966 to 2,25,506 cases in 1976 and
malaria deaths occurred from 1971.
61-65 68-70 71-75 76-80 81-85 86-90 91-95
Year
Phase III (1977-1990)
This phase was marked by the introduction of the
modified plan of operations (MPO) and the P. falciparum
containment programme (PfCP) under the NMEP as addi
tional inputs in 1978 to contain the resurgence recorded
during Phase II. These measures helped in improving the
malaria situation gradually. In 1980 SPR came down by
39% as compared to 1977. The reduction in SPR was 17%
in 1985 over* 1981. Between 1985-90 the malaria situa
tion, by and large, remained static. Interestingly, the
Table I.
Fig. 2. Profile of deaths due to malaria in the NE region of India
(1961-95)
The current epidemiological situation (1991-95) of
malaria25 in the different north-eastern states is presented
in Table I. The states of Arunachal Pradesh and Mizoram
together contribute to 22% of malaria positives and 11%
of Pf cases in the NE region with 5% share in its popula
tion, while Manipur and Nagaland (which together consti
tute 10% population of the region) contribute only 3% of
positives and 2% of Pf cases. It is to be noted that the
Malaria profile in different north-eastern states
State
Population*
BSE*
POS*
Pf*
Assam
SPR
SfR
Pf%
API
22428722
2668789
141013
92008
5.3
3.5
65.7
6.3
Arunachal Pradesh
819400
228795
32484
5657
14.2
2.5
17.4
39.6
Manipur
1826000
177146
3430
1898
1.9
1.1
55.3
1.9
Meghalaya
1860000
214288
14205
7938
6.6
3.7
55.9
7.6
Mizoram
684000
227943
15568
8361
6.8
3.7
53.7
22.8
Nagaland
1274000
45811
2576
564
5.6
1.2
21.9
2.0
Tripura
2750000.
191029
8605
6626
4.5
3.5
77.0
3.1
Total
3164^322
3753801
217881
123052
5.8
3.3
56.5
6.9
♦Mean figure between 1991-1995
BSE : Blood slide examined; POS : Malaria positive cases; Pf: Plasmodium falciparum; SPR : Slide positive rate; SFR : Slide falciparum rate;
Pf %: Plasmodium falciparum percentage; API: Annual parasite incidence
Source: Reference 25
24
NE region live in areas having annual parasite incidence
(API) below 2,55% population live in areas between 2-10
API and about 15% population live in areas recording API
higher than 10 (Table II).
Assam
Assam is the largest state in NE region (71% popula
tion) and has the maximum number of positives (64.7%)
and Pf (74.8%) cases. Of the 23 districts of Assam, four
viz. Karbi Anglong, Kokrajhar, Darang and N.C. Hills, have
the highest endemicity of malaria and contribute to 41%
of total positives and 32% of Pf cases in the state average
while contributing only to 12.3% of the population. The
districts of upper Assam on south bank of Brahmaputra
river including Dibrugarh, Sibsagar and Jorhat are the least
endemic for malaria. These three districts together consti
tute 12% of state population but contribute only 0.43% of
malaria positives and 0.49% of Pf cases.
Arunachal Pradesh
Fig. 3. Malaria endemicity pattern of NE region of India (1991-95)
latter two states are affected by insurgency and law and
order problems resulting in operational deficiency. Ma
laria endemicity of various north-eastern districts is de
picted in Fig 3. It is seen that 30% of the population of the
Table II.
Geographically this is the largest state of the NE re
gion with an area of83,473 km2 and the lowest population
density. This state contributes 2.6% population in the NE
region whereas it has 15% total positives and 5% Pf cases
in the region. In general the hill and foothill areas of
Arunachal Pradesh adjacent to Assam are highly endemic
Stratification of NE region according to annual parasite incidence (API)
<2 API
2-10 API
>10 API
Population/
No. of districts
Population/
No. of districts
Population/
No. of districts
State
Total
population/
No. of districts
Assam
22428722/23
6331872/ 7
(28.2%)
13169408/12
(58.7%)
2927442 / 4
(13.1%)
Arunachal Pradesh
819400/10
6600/ 1
(0.8%)
54200/ 1
(6.6%)
758600/ 8
(92.6%)
Manipur
1826000 / 8
1443000/ 6
(79.0%)
383000 / 2
(21.0%)
0/ 0
Meghalaya
1860000/ 3
0/ 0
1614200 / 2
(86.8%)
245800/ 1
(13.2%)
Mizoram
684000/ 4
0/ 0
0/ 0
684000 / 4
(100%)
Nagaland
1274000 / 7
646000/ 2
(50.7%)
628000/ 5
(49.3%)
0/ 0
Tripura
2750000/ 3
1289000/ 1
(46.9%)
1461000/ 2
(53.1%)
0/ 0
Total
31642122/58
9716472/17
(30.7%)
17309808/24
(54.7%)
4615842/17
(14.6%)
API calculated on the basis of mean population and malaria positives (1991-95)
Figures in parentheses are per cent population in that category
Source: Reference 25
25
/or malaria with an API of >15. As per NMEP data,
/ Arunachal Pradesh has a low Pf incidence. However, sev
eral studies have shown high (>60%) Pf incidence in dif
ferent parts of the state26*27.
Meghalaya
There are only 3, predominantly tribal districts, viz.
Garo Hills, Khasi Hills and Jaintia Hills (NMEP reporting
districts) in this hilly state. The Garo Hills district has the
highest Pf incidence (90%) in contrast to a very low (3.4%)
Pf incidence in the Jaintia Hills.
Manipur
Of the 8 districts in the state, 3 are valley districts and
5 are hilly districts. Four districts viz. Churachandpuf,
Imphal, Bishenpur and Thouvel are highly endemic con
tributing together 85% of malaria cases and 90% of Pf
cases.
Mizoram
There are 4 districts in this hilly, malaria endemic state.
Two districts viz. Aizwal East and Aizwal West are rela
tively more endemic contributing 61.4% of positives and
75.5% of Pf incidence.
Nagaland
This hilly state has 7 districts, all of which are highly
endemic for malaria. District Mokokchung has the high
est SPR (8.2%) closely followed by Phek district (6.53%).
In the remaining districts SPR varies between 3.5 and 5.8%
and Pf proportion between 10.6 and 39%.
Tripura
Tripura, the second smallest state of India, is
surrounded on three sides by Bangladesh and on one side
by Assam and Mizoram. Of the 3 districts in the state,
South Tripura is the most endemic contributing 62% and
58.6% of malaria positives and Pf cases of the state,
respectively.
Drug Resistance Profile
Resistance to chloroquine in P. falciparum was first
detected in 1973 from Manja PHC, Karbi Anglong
district of Assam4. Regular monitoring of drug resistance,
however, started from 1978 onwards under the Pf moni
toring scheme ofNMEP. A review of various in vivo chlo
roquine resistance studies carried out in Assam28 between
26
1978-93, revealed that Pfwas sensitive only in 34.2% cases,
resistant in 47.9% (RI 35.6%, RII 6.5%, RIII 5.8%) and
S/RI type in 17.9%. It is felt that chloroquine resistance to
Pf has not yet been fully stabilised in Assam and
chloroquine failure at the RI level is increasing leading to
higher morbidity due to repeated recrudescences. A simi
lar picture of chloroquine resistance is seen in the other
north-east states. Studies carried out by Pf monitoring
teams between 1978 to 1995 revealed that 47 of the 59
surveyed PHCs had resistance cases of all categories25. In
addition to chloroquine, confirmed resistance to long act
ing sulpha and pyremethamine combination drugs29 and
reduced efficacy to quinine30 has also been recorded from
the NE region. P. vivax resistant to antimalarials has not
been reported from this region.
Malaria Paradigms in the NE Region
The spatial distribution of malaria in the north-east is
not homogeneous and its transmission dynamics and
intensity is governed by a large number of stable and un
stable, biotic and abiotic factors in different paradigms. A
malaria paradigm is defined as a specific situation sup
porting a level of malaria endemicity which is dependent
on local environmentaland socio-economical activities25.
Different paradigms of malaria in the north-east show wide
variations and within the paradigms there sometimes exist
sub-paradigms which govern the malaria situation to a
considerable degree in the region. On the basis of the ex
isting malaria situation the following paradigms of ma
laria can be identified in the NE region of India.
Tribal area malaria
These areas are predominantly hilly with deep forests/
disturbed forest fringes, rich in biodiversity, crisscrossed
by hilly streams and characterised by a high concentration
of tribals with low population density. In these areas ma
laria is stable-with prolonged transmission and high Pf
preponderance. Resistance to chloroquine in Pf is usually
widespread along with a focus of resistance to sulpha and
pyremethamine combinations. An. dirus, An. minimus and
An. fluviatilis alone or in combinatiomare the major vec
tors which are refractory to control. Inadequate health in
frastructure and lack of treatment facilities at the village
level is an added disadvantage in these areas31. In this
paradigm the adults develop sufficient immunity to
malaria whereas the children in the absence of immunity
suffer and die32. It has been reported that 7.4 million tribal
population out of 27.1 million rural population in the
north-east contribute 6% of total malaria and 11% of Pf
€
Table HI. Prevalence of tribal population vs malaria incidence (1991-1995) in north-east India
No. of
districts
Population
BSE
(ABER)
POS
(SPR)
Pf
(SfR)
% Population
to total
% Malaria
positives
to total
0-5
6
6589726
800773
(12.2)
21450
(2.7)
17260
(2.2)
20.9
9.9
6-10
3
3372298
343780
(10.2)
7188
(2.1)
4855
(1.4)
10.8
3.3
11 -25
8
10250707
1149007
(11.2)
75620
(6.6)
42507
(3.7)
32.7
35.2
>25
41
11188124
1242302
(Hl)
110778
(8.9)
57Q34
(4.6)
35.7
53.1
Total
NE region
58
31400855
3535862
215036
121656
100
100
% of tribal
population
BSE : Blood slide examined; ABER : Annual blood examination rate; POS : Malaria positive cases; SPR : Slide positive rate;
SfR : Slide falciparum rate; Pf: Plasmodium falciparum
Source: Reference 25
cases31. Published data on malaria in the north-eastern
states25 reveal a similar picture on analysis (Table III).
Predominantly tribal areas (areas with >25% oftribal popu
lation) contributing 35.7% of the population of north-east,
have 53% malaria cases in th^ region whereas the
predominantly non tribal areas (areas with <10% of tribal
population) contribute only 13% of total cases though
having almost equal population ie. 31.7%. The correlation
between malaria incidence (API) and proportion of tribal
population was, however, weak. Under tribal area malaria
two sub-paradigms can be further identified.
Deep forest malaria : The forests in the NE region are
tropical, evergreen monsoon type where the high
humidity and temperature range favour vigorous growth
of trees resulting in a thick shady canopy. An. minimus is,
more or less, absent in these areas33 and malaria is trans
mitted chiefly by An. dirus. The individuals involved in
timber collection and tree felling stay for variable periods
ranging from a few hours to a few nights, in the forest
camps and face the risk of contracting malaria. Such people
(usually labourers) after falling sick in forest camps
return to their native villages for treatment and convales
cence and setup a local transmission chain. Jhum cultiva
tors are another vulnerable group of people in this
sub-paradigm who often sleep in hilly forest areas in small
thatched sheds, usually open from the sides, for variable
periods both during the sowing and harvesting of crops
and get exposed to infected An. dirus and the hazards of
malaria.
Forest fringe malaria : Usually in the foothills and plains
cultivation is done after clearing a small forest which
disturbs the natural ecology of the area. Malaria in such
forest fringe areas with disturbed ecology is maintained
both by An. minimus and An. dirus. The transmission in
these areas is intense and prolonged with moderate to high
endemicity. This sub-paradigm also encompasses those
areas where massive deforestation for retrieving cultivable
land and timber has taken place. Usually in such areas
malaria is endemic with wide fluctuations and is usually
maintained by An. minimus and An. fluviatilis and
possibly by An. philippinensis/nivipes.
Border area malaria
The north-east shares international borders with
Bhutan, China, Myanmar and Bangladesh. These border
areas are mostly hills and foothills with thick forest cover,
poor communication and inadequate health infrastructure.
The highly porous border allows frequent legal and illegal
exchange and mixing of local populace from both sides.
These factors facilitate the high malaria transmission in
the border districts. Of the Indo-Chinese border districts,
Tawang district (Arunachal Pradesh) is situated at a high
altitude and is free from malaria. Besides, the northern
parts of all other Indo-China border districts are also free
from malaria and only their southern parts, contiguous with
the foothill areas of Assam are malarious. Malaria in the
Indo-Bhutan, Indo-Myanmar and Indo-Bangladesh border
districts is hyper- to holo- endemic in nature. The
27
vulnerable population groups in this paradigm are the per
sonnel ofthe security forces and Border Road Organisation.
These are mixed population groups with varying levels of
immunity against malaria. The military and paramilitary
forces keep on moving from non-malarious to malarious
areas and vice versa and in the process get exposed to local
strains of malaria parasites causing enhanced transmission.
The malaria epidemiological data of the international bor
der districts of the NE region are shown in Table IV. The
SPR and SfR in the border districts were significantly
higher than in the non border districts.
Table IV. Malaria profile (1991-1995) in the international
border districts of NE region
Pf
SPR*
SfR Pf%
32175
4.8
3.3
67.5
8.3
2.9
34.0
1436
13.6
1.2
8.9
74178
46662
9.1
5.7
62.9
158066
59815
87101
35951
4.8
3.8
3.3
2.3
67.5
60.1
Category
BSE
Positive
Indo-Bangladesh
border
986744
47671
IndO'Myanmar
border
242788
20104
6828
Indo-China
border
118561
16113
Indo-Bhutan
border
814009
Total border area 2162102
Total non-border 1591699
area
BSE : Blood slide examined; Pf: Plasmodiumfalciparum.,
SPR: Slide positive rate; SfR : Slide falciparum rate;
Pf %: P. falciparum percentage
Source: Reference 25
Organised sector malaria
The NE region has large mineral reserves, the explo
ration and extraction of which is done by organised
sectors employing a large work force drawn from differ
ent parts ofthe country. Similarly the tea industry is a major
organised sector of the economy in this area. In addition,
many developmental projects such as power generation
and road and rail line construction are being executed in
the region. Malaria in all these sectors, could be clubbed
under this paradigm. Being well organised, these segments
have their own health delivery system. As far as malaria is
concerned the NMEP has only a minimal presence in these
sectors. The health institutions in these sectors, being pri
marily curative in nature so far as malaria is concerned,
lack proper and systematic record maintenance and it is,
therefore, difficult to assess the real epidemiological pic
ture of malaria in this paradigm. In this paradigm 3 sub
paradigms can be identified.
Oil and coal sectors : These sectors are usually located in
forest and forest fringe areas in the foothills and plains of
the NE region. Generally workers engaged in drilling and
exploration, etc. in the open areas are exposed to mos
quito bites. The vulnerability of these sectors was identi
fied by the Government of India as early as 1945 when the
Nazira and Margarita coal fields pilot project for malaria
control by DDT application was launched3.
Tea sector : Tea industry is one of the most important
sectors of the economy of the north-east. Most of the tea
gardens are located in Assam, Arunachal Pradesh and
Tripura in the foothill malarious'areas. In Assam alone
there are 848 tea gardens employing 5,41,661 labourers7.
This community comprises a mixed population of various
ethnic groups which had migrated from other parts of In
dia many generations earlier. Malaria was a serious prob
lem in these gardens affecting the production. Hence, even
before the institution of any organised control elsewhere,
various attempts were made to control malaria in the tea
gardens3,34. Regular data on the malaria morbidity in the
tea gardens are lacking due to the absence of a reporting
system and poor coordination between the tea garden man
agement and tfjp state health department. Nevertheless,
recent studies indicated a very high malaria prevalence
with Pf preponderance35 and high degree of chloroquine
resistance36.
Developmental projects sector: Various developmental
projects being undertaken in the NE region like power,
roads, communication, irrigation, etc. invariably involve
aggregation of labourers in the proximity of highly ma
larious forested areas. A wide variation in transmission
dynamics is seen from project to project depending on the
location of the project site.
The above discussion on the various well identified
paradigms of malaria highlights the following important
features of malaria transmission in the north-east.
(i) Most ofthe areas, except the high mountainous regions,
in the north-east are endemic for malaria. However,
deep forested and forest fringe areas with disturbed
ecology in the hills and foothills, usually inhabited by
tribals of various ethnicity are hard core malarious
areas with high Pf preponderance and refractoriness
to control. Malaria is usually stable with high
asymptomatic carriers in these areas.
(ii) The stable nature of malaria endemicity in large areas
of the north-east region is destabilised by the extension
of human activities from outside which invariably
results in increased transmission and malaria
outbreaks. Movement of people from the hard core
areas to areas with low to moderate endemicity leads
to enhanced transmission because of dissemination of
different parasite strains.
(iii) The chief vectors of malaria in the NE region ie. An.
dims and
minimus are hygrophilic and well adapted
to the ecological conditions of the region. Their high
anthropophilie habits makes malaria transmission pos
sible even at low density levels.
measures should be able to improve the malaria situation
in north-east India. The improving malaria situation in
some of the western Pacific countries (having malaria situ
ation and problems similar to the NE region) is a reminder
of the fact that the constraints of drug and insecticide re
sistance and population movement are not intractable ob
stacles to malaria control if the right strategies are applied
in the right way, in the right place and at the right time40.
References
Conclusions
It is evident that the malaria situation in the NE region
is governed by a variety of specific ecological, epidemio
logical, geographical and social factors. Abundance of hills,
foothills, forests, inaccessible tribal areas, poor
communication and large scale population movement are
some of the reasons for maintenance of high endemicity
of malaria which is further compounded by the combina
tion of specialist vactor species and increasing drug resis
tance. The geographical spread of malaria, which was con
tracted after the introduction of the NMEP in the sixties,
resurged in the seventies and stabilised in the eighties, has
reverted to expansion in terms of area and intensity in the
nineties. Despite the control efforts by the government the
malaria situation in the NE region has progressively dete
riorated. This in retrospect can be attributed to a combina
tion of factors-(i) failure to sustain residual insecticide
spray coverage due to various technical, administrative and
operational reasons; (ii) selection of exophilic and
exophagic vector species under DDT pressure; (iii) selec
tion of resistant malaria parasite strains under extensive
antimalarial drug pressure; (iv) rapid developmental works
causing tropical aggregation of labourers and; (v) insur
gency related law and order problems seriously affecting
control activities and resulting in movement of people from
low to high endemic areas and vice versa. From the past
experience it can be said that in order to tackle the malaria
situation effectively in the north-eastern states newer con
trol technologies (both for vector and parasite), sensitive
to local situations, acceptable by the local population and
in accordance with changing vector behaviour, need to be
introduced. In this context insecticide treated bed nets have
shown very promising results in the north-eastern condi
tions37. Similarly artimisinin derivatives have been found
to be extremely effective in the treatment of malaria in
this region38. Recently the Government of India has modi
fied its control strategy and introduced a new Malaria
Action Programme39 for problematic areas in the country
including the north-east. It is hoped that these tools and
1.
Sharma, V.P. Reemergence of malaria in India. Indian J Med Res
103:26, 1996.
2.
Molinaeux, L. The epidemiology of human malaria as an expla
nation of its distribution including some implications for its con
trol. In : Malaria. Principles and Practice ofMalariology (Vol
2). Eds, W.H. Wernsodorfer and I. McGregor. Churchil
Livingstone, London. 1988, p 913.
3.
Malaria and Its Control in India (Vol 1). Directorate of National
Malaria Eradication Programme (DGHS). Government of India,
New Delhi, 1986, p 1.
4.
Sehgal, P.N., Sharma, M.I.D., Sharma, S.L. and Gogoi, S. Resis
tance to chloroquine in falciparum malaria in Assam state. J
Commun Dis 5 : 175, 1975.
5.
Epidemiological Consideration for Planning Malaria Control in
Southeast Asia Region (Southeast Asia Series no. 17). Eds. A.V.
Kondrashin and K.M. Rashid. WHO Regional Publication,
SEARO, New Delhi. 1987, p 1..
6.
Roy, B: and Irshad Ali, A.N.M. Shifting cultivation and forest in
north-east India. In : People of the Himalayas, Ecology, Culture,
Development and Change. Ed. K. Mahanta. Kamala-Raj Enter
prises, Delhi. 1997, p 135.
7.
Statistical Hand-book ofAssam 1993. Directorate of Economics
and Statistics, Government of Assam, Guwahati.
8.
Malhotra, P.R. and Mahanta, H.C. Check list of mosquitoes of
north-east India (Diptera: Culicidae). Oriental Insects 28 : 125,
1994.
9.
Rajagopal, R. Studies on persistent transmission of malaria in
Burnihat, Meghalaya. J Commun Dis 17: 29, 1985.
10.
Viswanathan, D.K., Das, S. and Oomen, A.V. Malaria carrying
anopheles in Assam with special reference to the results of twelve
months dissection. J Mai Inst India 4 :297, 1941.
11.
Baimai, V. Population cytogenetics of the malaria vector Anoph
eles leucosphyrus group. Southeast Asian J Trop Med Pub Health
19:667, 1988.
12.
Clark, R.H.P. and Choudhury, M.A. Observations on Anopheles
(eucosphyrus in Digboi area of upper Assam. J Mai Inst India 4 :
103, 1941.
13.
Sen, A.K., John, V.M.. Krishnan, K.S. and Rajagopal, R. Studies
on malaria transmission in Tirap district, Arunachal Pradesh
(NEFA). J Commun Dis 5 : 98, 1973.
29
14.
Das, S.C. and Baruah, I. Incrimination of Anopheles minimus
Theobald and Anopheles balabacensis Baisas (An. dirus) as ma
laria vectors in Mizoram. Indian J Malarial 22 : 53, 1985.
Assam, India. Third National Seminar on Malaria and Other Tropi
cal Diseases, Bangalore (Abstract no. 68). 1997.
29.
Barkakaty. B.N.. Chakravorty. N.K. and Narasimham. M.V.V.L.
Efficacy of sulfalene and pyremethamine combination drugs alone
and with quinine in treatment of P. falciparum cases in chloro
quine resistant areas of north-east India. J Commun Dis 22 :178.
1990.
30.
Barkakaty. B.N. and Narasimham. M.V.V.L. Efficacy of a low
dose oral quinine therapy in Plasmodium falciparum cases of
Assam. Meghalaya and Arunachal Pradesh in India. J Commun
Dis 23:248. 1991.
15.f Dutta, P., Bhattacharyya, D.R. and Dutta, L.P. Incrimination of
Anopheles dirus as a vector of malaria in Dibrugarh district, Assam.
Indian J Malariol 26'. 149, 1989.
16.
Kalra, N.L. Forest malaria vectors in India: Ecological character
istics and epidemiological implications. In : Forest Malaria in
Southeast Asia (Proceedings of an Informal Consultative Meet
ing). Eds. V.P. Sharma and A.V. Kondrashin. WHO/MRC, New
Delhi, 1991, p 93.
17.
The biology of malaria parasites. WHO Tech Rep Ser 743 : 118,
1987.
31.
18.
Kareem, M.A., Singh, V.K., Bhatnagar, V.N., Krishnamurty, B.S.,
Das, M. and Sharma, G.K. A preliminary report on some
entomological observations in malaria endemic areas of Kamrup
district, Assam. J Commun Dis 17:29, 1985.
Pattanaik. S., Sharma, V.P.. Kalra. N.L.. Orlov. V.S. and Sharma.
R.S. Malaria paradigms in India and control strategies. Indian J
Malariol 31 : 141, 1994.
32.
Kondrashin, A.V., Jung, R.K. and Akiyama. J. Ecological aspects
of forest malaria in Southeast Asia. In : Forest Malaria in South
east Asia (Proceedings of an informal consultative meeting).
Eds. V.P. Sharma and A.V. Kondrashin. WHO/MRC, New Delhi.
1991, p 1.
33.
Narasimham. M.V.V.L. Perspectives of foiest malaria in India.
In : Forest Malaria in Southeast Asia (Proceedings of an Informal
Consultative Meeting). Eds. V.P. Sharma and A.V. Kondrashin.
WHO/MRC, New Delhi. 1991, p 81.
34.
Gillroy, A.B. Increasing malaria during an eradication programme :
A study on the tea estates in Assam. 1964-68. Trans Roy Soc Trop
Med Hyg 64 : 551. 1970.
35.
Dev. V. iand Phookan. S. Malaria prevalence in tea estates of
Brahmaputra valley of Assam. India. J Parasitic dis 20:189.1996.
36.
Gogoi. S.C.. Dev. V., Choudhury. B. and Phookan. S. Suscepti
bility of Plasmodiumfalciparum to chloroquine in tea garden tribes
of Assam, India. Southeast Asian J Trop Med Pub Health 26:
228, 1995.
37.
Janakara, B.R.. Wajiullah. Shahi. B.. Dev. V.. Curtis. C.S. and
Sharma, V.P. Deltamethrin impregnated bed nets against An.
minimus transmitted malaria in Assam. India. J Trop Med Hyg
98:73,1995.
38.
Mohapatra, P.K., Khan. A.M.. Prakash. A.. Mahanta. J. and
Srivastava, V.K. Effect of a I p of arteether on uncomplicated
falciparum malaria cases in upper Assam. Indian J Med Res 104 :
284,1996.
39.
Operational Manualfor Malaria Action Programme (MAP). 1995.
Directorate of National Malaria Eradication Programme (DGHS).
Government of India. New Delhi. 1995. pl..
40.
Kondrashin. A.V. and Trigg. P.I. Control of malaria in the world.
Indian J Malariol 34 : 92, 1997.
19.
Prakash, A., Mohapatra, P.K. and Srivastava, V.K. Vector incrimi
nation in Tamulpur Primary Health Centre, district Nalbari. lower
Assam during malaria outbreak, 1995. Indian J Med Res 103 :
146,1996.
20.
Dutta, P. and Baruah, B.D. Incrimination of Anopheles minimus
Theobald as vectors of malaria in Arunachal Pradesh. Indian J
Malariol 24 \ 159, 1987.
21.
Bhatnagar, V.N., Dwivedi, S.R., Mishra, B.G. and Das, M. De
tection and incrimination of Anopheles minimus Theobald 1901
as malaria vector in foothill areas of Nagaland, India. Indian J
Malariol 19: 129, 1982.
22.
23.
24.
Prakash, A., Bhattacharyya, D.R., Mohapatra, P.K. and Mahanta.J. Current insecticide susceptibility status of Anopheles minimus
Theobald in Assam. J Commun Dis 28 : 143, 1996.
Subbarao, S1K., Nanda, N., Vasantha, K., Dua, V.K., Malhotra,
M.S., Yadav, R.S. and Sharma, V.P. Population cytogenetic evi
dence for three sibling species in Anopheles fluviatilis (Diptera:
Culicidae). Ann Entomol Soc Am 87: 116, 1994.
Nanda, N., Joshi, H., Subbarao, S.K., Yadav, R.S., Dua, V.K. and
Sharma, V.P. Anophelesfluviatilis complex, host feeding pattern
of species S, T and U. J Am Mosq Control Assoc 12 : 147, 1996.
25.
Epidemiology and Control ofMalaria in India. Eds. R.S., Sharma,
G.K., Sharma, and G.P.S., Dhillon. Directorate of National Ma
laria Eradication Programme (DGHS), Government of India, New
Delhi, 1996,p 1.
26.
Satyanarayana, S., Sharma, S.K., Chelleng, P.K., Dutta, P., Dutta,
L. and Yadav, R.N.S. Chloroquine resistant P. falciparum
malaria in Arunachal Pradesh. Indian J Malariol 28: 137,
1991.
27.
28.
30
Dutta, P. and Bhattacharyya, D.R. Malaria survey in some parts
of Namsang circle of Tirap district, Arunachal Pradesh. J Commun
Dis 22 :92,1990.
Mohapatra, P.K., Prakash, A., Borgohain, B.K. and Mahanta, J.
Chloroquine resistance profile of Plasmodium falciparum in
This article has been contributed by Dr. P.K. Mohapatra and
Dr. Anil Prakash, Sr. Research Officers, Dr. D.R. Bhattacharyya.
Research Officer and Dr. J. Mahanta, Director, Regional
Medical Research Centre, Dibrugarh.
ICMR NEWS
Dr. N.K. Ganguly, formerly Professor and Head,
Department of Experimental Medicine and Biotechnology,
Postgraduate Institute of Medical Education and Research,
Chandigarh, has taken charge as the Director-General of
the Indian Council of Medical Research on March 12,1998.
Recipient of several national and international awards,
Dr. Ganguly has contributed extensively in areas of
microbiology, immunology, experimental medicine, bio
technology, etc with over 500 research/review articles to
his credit in several national and international journals.
He has been associated in various capacities with several
reputed science and technology agencies.
♦♦♦
***
***
The following meetings of various technical groups/
committees of the Council were held at New Delhi:
Meetings of the Project Review Committee (PRC)/
Expert Groups (EGs) held :
PRC on Oncology, Pathology and
Environmental Health
February 23, 1998
EG on Anti-tobacco Education
February 26, 1998
EG on Evaluation of Pregnancy
Test Kits
March 9, 1998
Meetings of the Task Forces (TFs) held :
TF on Mobile Unit approach tomeet reproductive and child
health (RCH) needs of women
February 23-24, 1998
TF on involvement of
Practitioners in Indian systems
of medicine in the delivery of
RCH services
February 26-27,1998
TF on district nutrition project
March 9,1998
Participation of ICMR Scientists in Scientific
Events:
Dr. P.R. Narayanan, Director, Tuberculosis Research
Centre, Chennai, participated in a conference on Global
Disease Elimination and Eradication as Public Health
Strategies at Atlanta (February 23-25, 1998).’
Dr. Padam Singh, Director, Institute for Research in
Medical Statistics, New Delhi, participated in the XXXI
session of the UN Commission on Population and
Development at New York (February 23-27,1998).
Dr. U. Sengupta, Director and Dr. B.K. Giridhar, Dy.
Director (Sr. Grade), Central JALMA Institute for Lep
rosy, Agra, participated in a WHO meeting on the Future
Role of Leprosy Training and/or Research Institutions at
Addis Ababa (February 25-26, 1998).
Dr. H.N. Saiyed, Director, National Institute of Occu
pational Health, Ahmedabad, participated in the WHO
regional consultation on Promotion of National Chemical
Safety at Bangkok (March 4-6,1998).
ICMR AIDED SYMPOSIA/SEMINARS/WORKSHOPS/COURSES/CONFERENCES
Symposium/Seminar/Workshop/
Date & Place
Contact Address
Course/Conference
National Workshop on Strategies for Sustainable
Rural Development
March 26-27,1998;
(at Madurai)
Dr. Samuel Paul Raj, Head and Coordinator, School
of Energy, Environment and Natural Resources,
Madurai Kamraj University, Madurai-625021.
National Symposium on Affective Disorders: The
Indian Scene
March 28-29,1998;
(at Chandigarh)
Dr. Ajit Avasthi, Organising Secretary of the Symposium, Department of Psychiatry, Postgraduate
Institute of Medical Education & Research,
Chandigarh-160012.
Seminar on Women in the Age of HIV/AIDS
April 22-25,1998;
Cat Thiruvananthapuram)
Dr. Sabu Philip, Director, Institute for Inter
disciplinary Research and Training, Thinivananthapuram-695011.
31
COUNCIL’S TRAINING PROGRAMMES FOR 1998-99
Leprosy
•
At the Central JALMA Institute for Leprosy, Agra:
•
Multidrug Therapy Orientation Course in Leprosy for
Medical Officers (April 6-17, August 17-28, October
26-November 6; and December 7-18,1998).
Virology
•
At the National Centre for Laboratory Animal Science,
National Institute ofNutrition,. Hyderabad:
Diploma in Medical Virology (July 1998-May 1999).
Reproductive Biology
Training Course for Laboratory Animal Technicians
(June 16-July31,1998).
Occupational Health
At the Institute for Research in Reproduction, Mumbai:
•
Laboratory Animal Technology
•
At the National Institute of Virology, Pune:
Postgraduate Certificate Course in Nutrition (Decem
ber 1,1998-February 28, 1999).
Workshop on Andrology for Clinicians (November 1630,1998)
At the National Institute of Occupational Health,
Ahmedabad:
•
Endocrinology
Training Course on Environmental Hygiene Practice
(November 16-20,1998).
At the National Institute of Nutrition, Hyderabad:
•
Annual Certificate Course on Endocrinological Tech
niques and their Applications (August 1-September
15,1998).
Biomedical Statistics
At the Institutefor Research in Medical Statistics, Chennai:
•
Basic Course in Statistics for Postgraduate Medical
Students (July 1998).
•
Basic Course in Statistics for Medical Officers
(November 1998).
Nutrition
At the National Institute of Nutrition, Hyderabad:
•
M.Sc. in Applied Nutrition (June 1,1998-February 28,1999).
EDITORIAL BOARD
Members
Chairman
. Dr. N.K. Ganguly
Director-General
Dr. Badri N. Saxena
Dr. Bela Shah
Dr. LalitKant
Editor
Dr. N. Medappa
Printed and Published by Shri J.N. Mathur for the Indian Council of Medical Research, New Delhi
at the ICMR Offset Press, New Delhi-110 029
R.N. 21813/71
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