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Sunil Gomber
Lalitha Kabilan
From the Department of Pediatrics, University College of Medical Sciences and Guru Teg Bahadur
Hospital and Malaria Research Centre, Indian Council of Medical
Research, Delhi, India.
Reprint requests: Dr. Sunil Gomber, F-4, Vijay Nagar, Delhi-llOOO9, India.
Manuscript Received: September 22, 1998; Initial review completed: October 7, 1998;
Revision Accepted: December 14, 1998.
Malaria has re-emerged as one of main public health problems
leading to increased morbidity and mortality. It is a serious
problem in the poor countries. Thirty six per cent of world's
total population is exposed to risk of malaria( 1). In India,
malaria peaked in 1976 following which the Government of India
launched a modified plan of operation in 1977 to reduce its
incidence. The problem was brought under control and malaria cases
had been static till 1993. Since 1994 focal
I outbreaks have been reported from various
parts of the country with occurrence of increased proportion of
cases of Plasmodium falciparum (Pf)(2). Keeping this in
mind a
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hospital based study on prevalence of malaria I in children (1-12
years) coming from urban I and peri urban areas of East Delhi was
carried out.
Subjects and Methods
A sample of population of children (1-12 yr) was examined by
enrolling children attending the Out-Patient Department of the
hospital for any reason. Children were recruited keeping in mind
the overall distribution at various ages. The prevalence of
malaria was found out by detecting parasites in their blood.
Gimesa' s staining method was used for detecting slide positivity
for malarial parasite. A total of 9442 blood smears were examined
at the Malaria Clinic established in the Department during
November 1994 to October 1995.
Results
Males and females comprised 59.7% and 40.3% of the sample,
respectively. Children between the ages of 1-3 yrs, 4-6 yrs, 7-9
yrs and 10-12 yrs, represented 32.9%, 28.4%, 19.5% and 19.2% of
the sample respectively. The slide positivity rate was 1.05%
(number of positive slides =
99, Plasmodium vivax (Pv) =
83; 0.88%; Pf = 16; 0.17%). P. vivax
was the predominant species among the positive cases. Differences
in seasonal parasite rates were significant. P. vivax
infections increased gradually from March and reached the peak of
transmission by September-October and thereafter showed a gradual
decline. However, Pf infections started in September and reached a
peak 'in October and declined thereafter. The number of malaria
positive cases at various ages were: 8 (1-3 yrs), 25 (4- 6 yrs),
38 (7-9 yrs) and 28 (10-12 yrs), respectively. The number of
positive cases represented as proportion of positive slides and
the total blood smears tested is shown in Table I.
Examination of 9442 blood smears revealed a
total of 62 out of83 (males - 36, females - 26)
infections with P. vivax gametocytes and 13/16 with P.
falciparum (males - 10, females - 3) gametocytes. Although
gametocytes of both the species were prevalent in all the age
groups, a higher positivity for gametocytes was seen in the age
group 7-9 years.
TABLE I
Positive Cases Represented as Positive Slides at Various Ages
|
Age group (yr) |
Cases examined |
Positive slides (%) |
| 1-3 |
3106 |
0.21 |
| 4-6 |
2682 |
0.93 |
| 7-9 |
1841 |
2.06 |
| 10-12 |
1813 |
1.05 |
Slide positivity rate was significantly lower in 1-3 year age
group (p <0.01).
Discussion
The results reveal that prevalence of malaria in East Delhi is low
but malaria due to Plasmodium falciparum has been occurring
in a significant proportion of cases. The trend is in concordance
with the national scenario(3). Occurrence of Plasmodium
falciparum malaria in increased proportions (16/99; 16.2%) may
complicate the disease epidemiology as rising trends of resistant
Plasmodium falciparum malaria are being noticed. Occurrence of
low immunity in the community results in the presence of cases
throughout the childhood(4) as shown in the present study.
However, there was significant decrease in the proportion of
positive cases below 3 years which could be explained due to the
fact that younger children mainly stay indoors and also remain
fully clothed. The difference in seasonal parasite rates of Pv and
Pf is due mainly to two reasons: (a) occurrence of Pv in
the earlier part of transmission (March-June) is usually due to
relapse cases because of lack of radical treatment given by
malaria workers to affected patients (GS Sonal, Deputy Director,
National Malaria Eradication Program, Personal Communication); and
(b) The difference in the extrinsic incubatiofl period which
is 16 days in Pv and as long as 22 days in Pf.
The problem of increased occurrence of Pf needs to be monitored on
a regular basis and containment measures should be immediately
taken as there is increased cost of its treatment and moreover
morbidity and mortality increases manifolds with Plasmodium
falciparum malaria.
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1.
Kondrachine A V, Trigg PI. Overview of malaria. Indian J Med Res
1997; 106: 39-52.
2. Lal S, Dhillion GPS, Sonal GS, Arora U, Nandi J. Drug
Resistance and Chemotherapy of Malaria in India; An Update. Delhi,
National Malaria Eradication Programme 1997; p I.
3. Sharma VP. Emerging problems in malaria control. Indian J Clin
Biochem 1997; 12: 4.
4. McGregor IA. Epidemiology and control of Malaria. In:
Epidemiology and the Community Control of Disease in Warm Climate
Countries, 2nd edn. Robinson D. Edinburgh, Churchill Livingstone
1985; pp 413-429.
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