Malaria remains a major global health problem, though incidence and mortality have decreased in recent years. In 2015, there were an estimated 214 million malaria cases and 438,000 deaths worldwide. India also has a significant malaria burden, with estimates of annual deaths ranging from 15,000 to over 200,000. Key malaria indices calculated to monitor disease burden and evaluate control programs include annual blood examination rate, annual parasite incidence, slide positivity rate, and percentage of malaria cases that are falciparum. These indices are calculated using population data and numbers of blood slides examined and positive results to measure aspects of local transmission and intervention effectiveness.

1. Epidemiological exercises:
Malaria indices
Dr. Rizwan S A
Asst. Professor (Community Medicine)
VMCH & RI, Madurai
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2. Three major types
• Rates and proportions
• Measures of association
• Diagnostic test validity
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3. RATE AND PROPORTIONS
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4. Rate and Proportions
• Demographic indices (CBR, CDR, MYP)
• MCH indicators
• Disease related indices (AR, SAR)
• Filarial indices
• Malarial indices
• TB indices
• Fertility indices (TFR, GFR, GMFR)
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5. INTRO TO MALARIA BURDEN
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6. WORLD
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8. Global disease burden in 2015
• New cases: 214 million (149–303)
– Africa (88%), South-East Asia (10%)
• Deaths: 438 000 (236 000–635 000)
• Between 2000 and 2015,
– malaria incidence fell by 37% globally
– malaria mortality fell by 60% globally
• Global Technical Strategy for Malaria 2016-2030
– reducing incidence by 90%; reducing mortality 90%;
eliminating malaria in at least 35 countries;
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9. Countries with malaria
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10. Trends in incidence and deaths
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11. INDIA
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12. Malaria endemic areas in India (API 2004)
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13. P. falciparum distribution in India
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14. High risk towns for malaria in India
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15. Pf%, API and Deaths (1995-2014)
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16. ABER, API, SPR, SFR, Deaths (2001-14)
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17. Trends in incidence
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18. Trends in cases and deaths (2001-14)
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19. Controversies in malaria burden
• India’s true malaria burden is a matter of
intense debate
• Different estimates of malaria deaths
– WHO: 15,000
– Million Deaths Study: 1.2-2.7 lakh
– ICMR committee: 40,297
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20. MALARIA INDICES
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21. Learning objectives
• To assess the burden of disease in a community in
terms of morbidity and mortality wrt malaria
• To calculate indices to monitor and evaluate national
health programs wrt malaria
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22. Malarial indices – 1/3
• Annual blood examination rate
=
No.of slides examined
Total popluation
X 100
• Annual parasite incidence
=
Confirmed cases during one year
Population under surveillance
X 1000
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23. Malarial indices – 2/3
• Annual falciparum incidence
=
Confirmed cases of falciparum during one year
Population under surveillance
X 1000
• Slide positivity rate
=
No.of slides showing parasite
Total no.of slides examined
X 100
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24. Malarial indices – 3/3
• Slide falciparum rate
=
No.of slides showing falciparum
Total no.of slides examined
X 100
• Percentage of falciparum
=
No.of slides showing falciparum
Total no.of slides showing parasite
X 100
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25. Malaria control in India
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26. Objective and indicators
• To achieve API <1 by 2017
• At least 80% of those suffering from malaria
get complete treatment within 24 hours
• At least 10% of the population in high-risk
areas is surveyed annually (ABER >10%)
• At least 50% reduction in mortality by 2017
(2010 baseline)
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28. EXAMPLE PROBLEMS
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29. Ex. Problem 1
1. In a Community health centre, with a population of
1,00,000, the health workers collected 3725 blood
smears from fever cases during their home visits. In
the same year, 3275 blood smears were collected from
Outpatient departments. On examination 185 slides
were positive for P. vivax and 15 slides were positive for
P. falciparum. Calculate the all-possible malarial indices.
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30. Ex. Problem 1
Given:
– Population = 100000
– Blood smears collected from fever cases home visits = 3725
– Blood smears collected from Outpatient departments = 3275
– Slides positive for P. vivax = 185
– Slides positive for P. falciparum = 15
• Annual blood examination rate = (3725+3275)/100000 X 100 = 7%
• Annual parasite incidence = (185+15)/100000 X 1000 = 2 per 1000 population
• Annual falciparum incidence = 15/100000 X 1000 = 0.15 per 1000 population
• Slide positivity rate = 200/7000 X 100 = 2.8%
• Slide falciparum rate = 15/7000 X 100 = 0.2%
• Percentage of falciparum = 15/200 X 100 = 7.5%
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31. Ex. Problem 2
2. Population of a PHC is 25000. A total of 200
peripheral blood smears were made. 38 of them
tested positive for P.vivax, 40 for P.Falciparum
and 10 showed both. Calculate the indices for
malaria control in the area.
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32. Ex. Problem 2
• API= 88/25000*1000= 3.5 per 1000
population
• ABER= 200/25000*100= 0.8%
• SPR = 88/ 200*100= 44%
• SFR= 40/200 *100= 20%
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33. Work out on your own 1
The following are the data available for Madurai
district with population 10,00,000 regarding Anti
malaria activities during the year 2010. Blood
smear examined = 80000 positive cases
detected PV = 2592, PF = 308. Calculate ABER,
API, AFI, SPR and Percentage of falciparum.
Interpret the results and mention remedial
measures.
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34. Work out on your own 2
• The following are the data from a Primary Health
Centre for the year 2015
• Total population = 30,000
• Blood slides collected by active surveillance =260
• Blood slides positive for parasite in above = 80
• Blood slide collected by passive surveillance = 140
• Blood slides positive for parasite in above = 40
• Among the positive slides, falciparum was seen in 9
Calculate the malaria indices and comment on them
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