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Indian Journal of Community Medicine

Epidemiological Assessment of the Trend of Malaria in Rural Western U.P.

Author(s): R. Das, Z. Khan P. Nath, A. Amir

Vol. 29, No. 3 (2004-07 - 2004-09)

Abstract:

Objectives: To find out the incidence of malaria in a delimited stable population of rural western Uttar Pradesh in the previous 10 years and use this data for forecasting the trend of Malaria.

Study design: Retrospective analysis of passive surveillance records.

Setting: Rural.

Participants: Patients with fever reporting to Rural Health Training Centre, Jawan for blood smear examination for suspected malaria from Jan. 1990 to Aug. 2000.

Study variables: Age, sex, fever, peripheral blood smear examination, population at risk.

Study Outcome: Annual blood examination rats slide positivity rate Annual parasite incidens proportion of malaria cases with gametocytes.

Statistical analysis: Proportions, mean, standard deviation.

Results: There has been a gradual rise in the annual incidence of malaria cases in Jawan block of Aligarh, which can be representative of the rural population of western Uttar Pradesh. The mean API at Jawan was found to be 11.02/1000 population (1990-99) which was much higher than the national avearage of 2.75/1000 population (1990-95). The mean SPR of 32.1% found in the present study (1990-99) was also much higher than the all India figure of 2.93% for the first half of the decade. The mean number of malaria cases detected in August 1990-99 was 27.1 (range 11 to 52) while in year 2000 it was 102. An epidemic of malaria was, therefore, raging and the peak predicted in September and October. Urgent measures need to be adopted for containment.

Key words: Fever, Malaria, Blood smear examination, Annual parasite incidence, Slide positivity rate, Annual blood examination rate.

Introduction:

Malaria is stilll the most important cause of fever and morbidity in India and many other tropical countries. There had been a sharp decline in the incidence of this dieases in the late 60s leading to high hopes for its eradication. However, by the mid 70's it became clear that eradication was not attainable for a number of reasons, including the development of resistance to insecticides in insect vectors, resistance to drugs in the parasite and political and administrative difficulties. Epidemics of malaria were being reported frequently, in the last few years, from Rajasthan and Haryana which are close to western Uttar Pradesh and also from the North Eastern states. Ever in Uttar Pradesh newspapers were reporting that malaria had assumed alarming proportions and official agencies were stating about control of the disease by spraying, drug distributing and other related activities. The present study was carried out to assess the epidemiological trend of malaria in a delimited population of rural western Uttar Pradesh, in the previous ten years and future projections.

Material and Methods:

The present study was carried out at the Rural Health Training Centre (RHTC) at Jawan, under the Department of Community Medicine, J.N. Medical college, Aligarh, U.P. The centre runs a malaria clinic and has the benefit of a well equipped laboratory and a medical record section, thus providing the back up for a passive surveillance centre. The services of the centre are utilized, in a major way, by residents of 6 surrounding villages, with very few seeking health services from other sources, while few patients from outside these villages also utilise its services.

For the purpose of calculating Annual Parasite Incidence (API) the mid year population of each year was estimated by using the arithmetic progression method (AP), taking the 1990 RHTC census, as base. Mid-year estimated population = P (L) + (4/12 x yearly increase) + (t x yearly increase) in t the postcensal year, where P(L) is the population of 1990 census and t is the number of years elapsed since last census1.

Details of fever cases and results of thick and thin peripheral blood smear examination from 1st Jan. 90 to 31st August 2000 were analysed.

Table I shows the age and sex distribution of the population of six villages surrounding the Rural Health Training Centre - Jawan, who utilize the health care services provided by the centre. This census was undertaken by field staff of RHTC and interns in January 1990.

Result and Discussion:

Table I : Age and sex distribution of population under RHTC - 1990.

Age in year Male Female Total
  No. (%) No. (%) No. (%)
0-1 267 (52.8) 239 (47.2) 506 (3.7)
1-5 943 (50.71) 916 (49.3) 1,859 (13.6)
5-15 1,926 (52.9) 1,716 (47.1) 3,642 (26.6)
>15 4,255 (55.4) 3,423 (44.6) 7,678 (56.1)
Total 7,391 (54.0) 6,294 (46.0) 13,685 (100.0)

Repeat census was done in 2000, by updation of the family details through door to door visits in the registered villages. Interns, nursing and MSW students did the updation under guidance of Medical Social Workers. The absolute increase in the population was found to be 4,216. This corresponds to an annual growth rate of 4.2%. For estimating the mid year population in the intervening years, it was assumed that the population had grown uniformly in size throughout the decade. Annual parasite incidence (API) was calculated for the estimated mid-year population taking 1990 as the base year.

Infants, constituting 3.7% of the population contributed to only 1.4% (range 0 to 9.6) of malaria cases. About a fifth of all malaria cases were found among the pre-school age (1-5 years) children (range 9.4 to 34.0) which constituted only 13.6% of the overall population. The school going children (5-15 years) while comprising nearly 27% of the population, contributed to 37% (range 20.4 to 50.3) of the disease. In the over 15 years age bracket (56% of population), malaria contributed to nearly 42% (range 25.1 to 52.6) of the disease load.

Thus on an average 4.7, 18.5, 17.7 and 9.4% of the population in the age groups of 0-1, 1-5, 5-15 and >15 respectively, suffered from malaria during the past ten years. The pre-school and school going children were found to be more vulnerable to this disease.

The lower susceptibility in infants could be attributed to two reasons; firstly, the social custom of keeping the infants well clothed and covered by sheets; secondly, infants born of immune mothers are, at least partially protected by maternal IgG durng the first 3-5 months. Similarly, population over 15 years of age, being exposed continuously to malaria develop considerable degree of resistance, thus probably decreasing the susceptibility in adults.

Table II : Smear examined annually, ABER, SPR, API, PF cases and % of cases showing gametocytes.

Year BSE
No.
ABER
(%)
SPR
(%)
API
(%)
+ve smear
showing gametocytes
P.F. cases
No.
1990 629 4.6 14.8 6.8 13 11
1991 685 4.9 42.8 20.1 7 7
1992 502 3.4 26.7 9.2 16 6
1993 594 3.9 28.2 11.0 25 4
1994 381 2.5 24.4 6.0 32 2
1995 584 3.7 29.9 11.0 19 11
1996 500 3.1 36.0 11.1 3 0
1997 323 1.9 37.5 7.3 13 0
1998 490 2.9 46.5 13.3 13 7
1999 699 4.0 36.1 14.4 3 11
Mean   3.5 32.1 11.0    
2000 (upto 31/8) 420 - - - - 3

Table II shows the ABER from 1990 to 1999 which ranged from 1.9 to 4.9% (mean 3.5%). This is quite low as compared to over 9% as reported by various States to the Directorate of National Anti-Malaria Programme2, while the recommendation of WHO is at least for 10% of the population.The reason for our low coverage was that only passive surveillance is done by the centre.

The slide positivity rate (SPR) of peripheral blood smears examined ranged from 14.8 to 46.5% with a mean of 32.1%. The corresponding figures of National Anti Malaria Programme stood much lower at 2.6 to 11.5%2. A SPR of 34.8% has been reported in passive surveillance for 1996 to 1998, in the port city of Mangalore, which is in greater congruity with our findings3. Lal et al have also reported SPR of 12.8% in their study in Lakhanmajra block of Rohtak for 19954.

Since ours is a clinic based surveillance programme and our interns under the guidance of PGs/Medical Officers use clinical skills to screen fever patients before subjecting them to blood smear examination, our SPR is quite high and are more in agreement with those of Bhutan (35.9%), Sri Lanka (24.2%) and even Myanmar (15.2%)5,6.

The Annual Parasite Incidence (API) for the population served by RHTC, Jawan from 1990 to 1999 has been shown in table II. The lowest API of 6 was recorded in 1994 and the highest of over 20 in 1991. Since 1994 a gradual increase in API could be seen except for the year 1997.

Lal et al have also reported a rising trend in API from 1991 to 1995 in their study in Lakhanmajra block of Rohtak, the figures being 3.7, 4.4, 8.3, 13.6 and 36.4 per 1000 population4. The corresponding national figures as reported by NMEP are quite low, being in range of 2.5 to 3.2 per 1000 population2. The API, as calculated for U.P. in 1990 stood at 0.71 per thousand population, although we recorded an API of 6.8 for the same year7. The mean API for our population for the period 1990 to 1999 was 11 per thousand population in comparison, the mean API for India from 1990 and 1995 has been 2.755. The highest figure of API in India in the recent past was 11.2, recorded in 1976. Our study indicated that API was increasing gradually, which is certainly a cause for worry. Similar trend, culminating in an epidemic, was seen in the Lakhanmajra study4.

Table II also shows the number of Plasmodium falciparum cases detected since 1990.

It was observed that in the years having a higher incidence of malaria, the SPR also went up proportionately. This was predictable since qualified medical personnel advised the blood smear examination only after clinical screening. Similar trend was observed by other study groups also4.

An interesting, but paradoxical association was seen between the API and the proportion of malaria cases showing gametocytes in their smear (Table II). This population is infective to mosquitoes and periods with higher proportion of malaria cases showing gametocytes in the peripheral smear should be associated with higher API. However, their association was found to be inversely related.

One of the explanations for this finding of ours could be, that many of our patients reported to us for BSE, only after having been given some medication by local practitioners. It is quite possible that they included some anti malarials, albeit in low doses. In years, having higher incidence of malaria, their index of suspicion for malaria is likely to be high. As a result, a substantial number of cases did not show gametocytes in their blood smears, though clinically they were suffering from malaria with certain stages of parasites being present in their blood.

The mean number of cases detected in the month of August alone from 1990 to 1999 was 27.1 (range 11 to 52), while the mean for cumulative cases till August was 60.7 (range 33 to 94). In comparison, during 2000, 102 cases were detected in August along and the cumulative figure till 31st August was 150. Both these figures were significantly more than (mean plus two standard deviations) any of the observations in the past 10 years. An epidemic was therefore, raging in Jawan block of Aligarh.

The most important reason for this increase in API was lack of concerted insecticide sparying activities, as under the modified plan of operation, routine spraying is not advocated for areas with API less than 2. On the other hand, the district health machinery found it hard to accept an API of over 2 per thousand population. As a result the situation went from bad to worse.

Conclusion and Recommendations:

In our study, in rural areas of Aligarh, the passive surveillance system for malaria has proved to be a cheap yet sensitive method for monitoring the trend of this disease. With the active surveillance system becoming more unreliable, owing to lack of work culture among peripheral health staff, rising costs because of low yield, transportation problems and official figures being gross under estimation of the problem, it is recommended that further multicentric studies be undertaken by independent agencies for quantification and stratification of malaria throughout the country.

Moreover, the strategies being followed presently for malaria control seem to be grossly inadequate and need a thorough revamp. Also, the few good epidemiological data that we have, and centres from where these emanate, must be put to best use, which, unfortunately, is not happening presently.

References:

  1. Foundation for Research in Health Systems - Health Monitor 1995, 147.
  2. Govt. of India (1995-96), Annual Report 1995-96. DGHS, New Delhi.
  3. Uday Kiran N. Strategies for Malaria control in Mangalore city, Ind. J. Community Medicine. Vol. XXIV, No. 4, Oct.-Dec. 1999, 172-4.
  4. Lal S, Vashisht BM, Punia MS et al. Containment of outbreak of P. falciparum malaria in community development block Lakhanmajra; Ind. J. of Community Medicine, Jan-Dec 1996; XXI (1-4): 28-33.
  5. WHO (1996). The World Health Report 1996. Fighting disease, fostering development, Report of the Director General - WHO.
  6. WHO (1996), Weekly Epidemiological Record No. 6, 9 Feb. 1996.
  7. Central Bureau of Health Intelligence, Health information of India-1991; DGHS, New Delhi.

Department of Community Medicine, J.N. Medical College, AMU, Aligarh, (202002)UP

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