This document provides an overview of the epidemiology of malaria. It discusses the history of malaria, including the discovery of the malaria parasite and mosquito transmission. It describes the global and Indian epidemiology, noting that most cases occur in Africa, Southeast Asia, and India. Four main malaria vectors in India are identified. The life cycle and modes of transmission of the malaria parasite are explained. Factors influencing the distribution of malaria like host, vector, environment, and socioeconomic conditions are summarized.

1. Epidemiology of Malaria
Presenter :
Dr. Ramkesh Prasad
PG student
Department of Community Medicine
Gauhati Medical College

2. Fossil mosquitos were found in geological strata 30 million old in Africa.
6 BC - Association of fever with stagnant water & swamps led to methods of
drainage practised by the Greek and Romans.
1820 - Quinine the active principle of Cinchona was isolated by Pelletier and
Caventou
1880 - Laveran first saw and demonstrated malaria parasite in the human RBC
1891 - Romanowski developed a new method of staining blood slide
1892 - Patrick Manson outlined the mosquito theory of malaria transmission
1897 – Sir Ronald Ross in Secunderabad, proved the transmission through
malaria parasite through mosquito
1899 - Battista Grassi with Bignami and Bastianelli described the full cycle of
development of human malaria parasite in Anopheles mosquitos
History

3. 1934 - Chloroquine was synthesized in Germany
1939 - Paul Miller discovered the insecticidal property of DDT
1945 - Venezuela was the first country to launch Eradication Program against
malaria
1946 - India started using DDT
1951 - DDT resistance reported from Greece
1952 - Primaquine developed by Elderfield in the USA
1953 - NMCP launched
1955 - WHO’s Global Malaria Eradication Campaign was inaugurated
1958 - NMCP was converted NMEP
1965 - 0.1 million cases reported with no death in India

4. 1971 - UMS launched
1972 - DDT banned in USA
1973 - Chloroquine resistance reported in Assam
1977 - NMEP was revised and upgraded and was called Modified Plan of
Operation
1982 - National Anti Malaria Drug Policy was first drafted
1994 - Resurgence of malaria in India
1995 - Malaria Action Plan came into effect
1998 – RBM launched
1999 - National Program was renamed as National Anti Malaria Program
2000 - Millennium Development Goal to eradicate malaria by 2015
2004 - NVBDCP launched

5. Problem Statement
WORLD
 At present 109 countries are considered endemic
 In 2008: 243 million cases
8,63,000 deaths
Malaria kills between 1.1 -2.7 million people each year worldwide, of
whom about 1 million are children under the age of 5 years, these
childhood deaths constitutes nearly 25% of child mortality in Africa.
85% AR
10% SEA
4% EMR
89% AR
6% EMR
5% SEA

7. Indian Scenerio
Pre Independence:
• The situation worsened in the early 19th
century.
Contributing factors was the establishment of the railways and irrigation
network.
•Due to the heavy death toll, economic loss, and risk to the lives of British
officers serving in vulnerable areas like Punjab, a lot of research was done for
malaria control.
•In the 1840s, attention was paid to proper drainage and chemoprophylaxis
was started with Quinine
•Malaria control were initiated in areas of economic to importance British
rulers..
• In 1909, the Central Malaria Bureau was formed in Kasauli for malaria
control and investigations.

8. Post Independence:
•Malaria Institute of India carried out systemic studies in Collaboration with
the Health Directorate of erstwhile Bombay Presidency from 1945-1952, and
formulated the strategy for malaria control program in India.
•In 1953 NMCP was launched .
•Prior to 1953, there were about 75 million cases with 0.8 million deaths per
year.
Current status:
. Accounts for 2/3rd
of the confirmed cases reported in the SEAR
•In 2009 1.56 million cases reported
•The major endemic areas in India are in the NE states, Andhra Pradesh,
Chhattisgarh, Gujarat, Jharkhand, MP, Maharashtra, Rajasthan and Orissa
•Orissa contributes to the highest no. of malaria cases in the country.

9. Year Total Malaria Cases
(million)
P. falciparum cases
(million)
Pf % Deaths due to malaria
1995 2.93 1.14 38.84 1151
1996 3.04 1.18 38.86 1010
1997 2.66 1.01 37.87 879
1998 2.22 1.03 46.35 664
1999 2.28 1.14 49.96 1048
2000 2.03 1.05 51.54 932
2001 2.09 1.01 48.20 1005
2002 1.84 0.90 48.74 973
2003 1.87 0.86 45.85 1006
2004 1.92 0.89 46.47 949
2005 1.82 0.81 44.32 963
2006 1.79 0.84 47.08 1707
2007 1.51 0.74 49.11 1311
2008 1.53 0.77 50.81 1055
2009 1.56 0.84 53.72 1144
2010 1.03 0.53 50.92 547
Countrywide Epidemiological Situation (1995-2010)

11. Malaria Paradigm
Endemicity Spleen Rate* Parasite Rate*
Hypoendemic ≤10% in children ≤ 10%
Mesoendemic 11-50% in children 11-50%
Hyperendemic >50% in children also high in adults
(>50%)
>50%
Holoendemic >75% in children but low in adult >75%
A malaria paradigm is defined as “a specific situation supporting a level
of malaria endemicity which is dependent on local environmental and
socioeconomic activities”.
•Unstable and Stable Malaria
•Based on endemicity
* Children between 2-9 years

12. Paradigm in relation to human activity as per WHO
1. Agriculture related malaria
Irrigated Agriculture Malaria
Non-irrigated Agriculture Malaria
Tree Plantation Malaria
Animal Grazing Malaria
2. Forest Economy Related Malaria
Deep forest Malaria
Forest Fringe Malaria
3. Urban Malaria
Urban mlaria
Peri-urban malaria
Slum malaria
Industrial malaria

13. NMEP in 1994 identified 4 malaria paradigms. However these paradigms are
more relevant from operational rather than epidemiological point of view
•Epidemic Prone Areas :
Semi arid Desert Areas
Semi arid Desert Areas with Canal Irrigation
Non-irrigated Semi –arid Areas
Ecosystem Supported by Lakes
Epidemic Prone Alluvial Plains of Indo Gangetic Areas
•Project Areas
•Tribal Areas
Hilly Rain forest
Hilly Deforested Cultivated Areas
Deciduous Forest in Peninsular Hills
•Urban Area

14. Malaria in Assam
Malaria has been a serious problem in the North East, mainly due to topography and
climatic conditions being congenial for perennial transmission.
Assam reports maximum malaria cases as well as P. falciparum followed by AP, Tripura
and Meghalaya.
Karbi Anglong, Kokrajhar, Udalguri, Darrang and NC Hills have the highest endemicity
of malaria, contributes to 41% of total positive and 32% of Pf cases in the state
( population 12.3%)
Dibrugarh, Sibsagar and Jorhat – least endemic. They altogether constitute 12% of state
population but contribute only 0.43% of malaria positives and 0.49% of Pf cases
There has been a steady decline in the no. of slide positive cases, no. falciparum cases
and no. of deaths in the past 5 years. But the proportion of the P. falciparum cases has
increased considerably.

15. Paradigms of Malaria
District Map of Assam with API

16. Malaria situation in Assam in last 5 years
YEAR BLOOD SMEAR
EXAMINED
TOTAL SLIDE
+ve
Pf +ve Pf % DEATH
2006 27,43,092 1,26,178 82,546 65.42 304
2007 23,99,836 94,853 65,542 69.10 152
2008 26,87,755 83,939 76,350 90.96 86
2009 30,21,915 91,413 66,557 72.80 63
2010
(up to
Sept)
34,82,110 48,452 40,993 84.61 30

17. Geographical Distribution :
Malaria once extended widely through out the world reaching as far north as 64ºN latitude
(Archangel in former USSR) and as far south as 32ºS (Cordoba in Argentina)
Today, however , malaria is almost exclusively a problem of the geographical tropics.
One of the greatest epidemics of modern times struck the former USSR after the First World War:
more than 10 million cases were reported in 1923-26 with at least 60,000 deaths
Epidemiology

18. Recipien
t
Donor
VectorParasite
Physical
Biological
Socioeconomic
Environmen
t
Agent
Human host
Epidemiology

19. Agent
PARASITE
Plasmodium vivax : has the widest geographical range, prevelant in many temperate zone,
tropics and subtropics
Plasmodium falciparum: commonest species throughout tropics and sub tropics
Plasmodium malariae: patchy presence in same area as Pf but much less common.
Plasmodium ovale: found mainly in tropical Africa but also ocassionally in West Pacific
Plasmodium knowlesi: emerging parasite, confirmed cases found in Thailand, Indonesia,
Borneo, Philippines, Singapore, Myanmar, Malaysia.

20. AGENT
Vector: Infected Female Anopheles mosquito
422 species throughout the world, 70 species are vectors of malaria under
natural conditions; of these 40 are of major importance.
Common vectors in India are:
Anopheles minimus
Anopheles dirus (An. baimaii)
Anopheles philippensis
Anopheles culicifacies
Anopheles stephensi
Anopheles annularis
Anopheles sundiacus
Anopheles fluviatilis
Anopheles varuna

21. Reservoir of infection:
Humans and Chimpanzee
Patient can be a carrier of several plasmodium species at the
same time
Children>adults, children epidemiologically better reservoir
Period of communicability:
P. vivax infection - 4-5 days
Falciparum infection - 10-12 days
Relapse: vivax, ovale, malariae
Recrudescence: falciparum malaria

22. Vector
Behaviour pattern of adult Anopheles:
Vector density: Dependent on availability of suitable larval habitat
Resting habits: All vectors of malaria in India are endophilic except for A. dirus which is
known to be exophilic. This habit of the vector (164)
Biting Time: of each vector species is determined by its genetic character
Breeding places: fresh and salt water, stagnant .
Flight range: 2-3 kms but strong seasonal winds may carry upto 30 kms or more from their
main breeding places.
Life span: Key factor in transmission
Vector needs 10-12 days, after an infective blood meal; to become infective-hence strategy
is to shorten lifespan<10 days

23. Mode of Transmission
Vectorial Transmission
Transfusion malaria
Congenital Malaria
Malaria in Drug addicts
Therapeutic Malaria

24. Distribution of different vectors in India

25. Bio-ecological Characteristics of the
Principal Vector in India
Species Zone of Influence Breeding Ecology Adult Behaviour
An. minimus NE States, North West
Bengal
Clear slow moving water with
grassy margin , swampy
vegetation and little shade,
irrigation ditches, crab holes
etc.
Resting Habitat: Prefer
human dwellings
Biting Time: 12 am – 2 am
Feeding habit: Predominantly
anthropophilic
An. dirus Deep forest in NE region Forest pools and stream with
decaying leaves. Burrow pits
along forest roads
Resting habitat: Exophilic,
may be endophagic. Rests
outdoor during the day.
Biting time: 12 am – 2 am
Feeding habit: Highly
anthropophilic
An. fluviatilis Foothills all along the
Himalayan range
Clearwater breeder, shallow
wells in monsoon, terraces
rice fields
Resting habitat: Human
dwellings
and cattle sheds.
Biting time: 8 pm -2 am
Feeding habit: Foothills:
highly anthropophilic, plains:
zoophilic

26. Species Zone of Influence Breeding ecology Adult Behaviour
An. culicifacies
(A, B, C, D)
Most parts of the
country
Wide Range: Usually
breeds in water not rich
in organic matter –
irrigation channels,
river bed, pools, tanks,
ponds, rice fields,
brackish water, hoof
marks etc.
Resting habitat: Predominantly
indoor rester-cattle sheds and
human dwellings
Biting time: 10:30 pm – 12:30
am
Feeding habit: Mainly zoophilic,
Indiscriminate feeder at high
density
An. stephensi All towns except NE;
rural area of arid/semi
arid zone except in the
North
Domestic and
Peri-domestic water
collection
Resting Habitat: Human
dwellings and cattle sheds
Biting time: soon after dusk;
4 am - 6 am
Feeding habit: Indiscriminate
feeder on humans and cattle
An. sundiacus Andaman & Nicobar
Islands
Brackish water with
algae, cleared
mangroves and
lagoons
Resting habitat: Often human
dwellings and less frequently in
cattle sheds
Biting Time: soon after dusk,
10 pm – 12 am
Feeding habit: Prefers human
blood

27. LIFE CYCLE OF PLASMODIUM

28. Importance of Extrinsic Incubation period
Insecticide use
Surveillance
Early diagnosis and PT. to avoid gametogony
Prevention of Relapse

29. Host
Sex: Male are more vulnerable due to more outdoor activities
Pregnant women : intensity of the sickness is more
Age: Children, infants become vulnerable from 3rd
month
Immunity: Africans have greater innate immunity to some types of malaria than other races
Red cell polymorphism and malaria:
HbAS: Protection against P. falciparum
HbC: Partial immunity to P. falciparum
HbF: Protective against P. falciparum
HbE: Partial protection against malaria
Duffy blood group: virtually absent in West Africans so they are unsusceptible to P. vivax
G6PD deficiency: Protective against P. falciparum
Hereditary ovalocytosis: highly resistant to P. falciparum and P. vivax

30. Housing: Ill ventilated, ill lighted houses – provide ideal indoor resting places for vectors
Sleeping Habit: Not sleeping under mosquito net exposed to the risk of getting the infection.
Occupation
•Agriculture and Irrigation
•Cattle grazing
•Migration of Population
•Road Transport and construction
•Movement of Military personnel
•Labour movement for execution of projects
•Human movement for fishing
•**** Incubation periods
•Clinical features

31. Environment
Season
Seasonal disease- July to Nov
Temperature
Optimum for parasite development in vector 20 -30ºC
Humidity
60% considered necessary
Rainfall
Provides opportunity for breeding of mosquitoes, gives rise to epidemics
Increases atmospheric humidity- necessary for survival of mosquitos
Drought
Small pools formed by half dry streams (e.g. Sri Lanka 1934-35)
Altitude-
Anopheles not found >2000-2500 metres
Man made malaria-
Burrow pits
Garden pools
Irrigation channels
Engineering projects,

32. Clinical Features
Typical : Sudden onset of high fever with rigors and sensation of
extreme cold followed by feeling of burning heat leading to profuse
sweating and remission of fever by crisis thereafter.
Atypical:
Cough and running nose
Diarrhea
Skin rashes
Joint pain
Symptoms of severe and complicated malaria:
Altered sensorium
Breathing difficulty
Severe Anemia
Dark coloured urine/Oliguria

33. Operational and Epidemiological Indices
ABER Reflects the adequacy and efficiency of case detection
mechanism
API If ABER is adequate, this parameter is the most important
criteria to assess the progress of eradication programme
SPR Whenever ABER is inadequate, this is a dependable parameter
for determining the progress of containment measure
SfR When ABER is adequate, SfR pinpoints the areas of Pf
preponderance
IPR Most sensitive index of recent transmission of malaria

34. Prevention and Control
Elimination of Reservoir: consists of making the infectious cases non-infectious by giving
treatment.
Chemoprophylaxis: Travellers from non-malarious to malarious areas
Military and paramilitary personnels moving into malarious area
Pregnant women living in endemic and hyperendemic areas
Breaking the Channel of Transmission: vector control
Antiadult measure: Residual spraying, space spraying, fogging
Antilarval measure: Source reduction
Biological control: Larvivorous fishes, bacteria
Personal Protection: Bed nets with insecticides
Mosquito repellants
Clothing
Awareness:
IEC should become a continuing activity to help strengthen early case detection and
prompt treatment,
Eliciting people’s participation in vector control

35. Thank You