K Sandeep
Health Services Department, DHS Office, Trivandrum.

 Corresponding Author: Dr. K Sandeep, MPH, Assistant Surgeon, Health Services Department, DHS Office, Trivandrum. E-mail: sandeepkerala@hotmail.com

ABSTRACT

Malaria is an important health problem  in many  parts of Asia, South America and Africa. Malaria is not eradicated form  Kerala  even  after implementation of various ma1aria control strategies.

Objective: Incidence of malaria in Kerala during the last 50 years and also the effectiveness of various malaria control programmes during the same period investigated.

Methodology: Secondary  data on malaria were collected from the various  health  reports  and  registers.  Malaria  was eradicated  from  Kerala in 1965. However  malaria returned to Kerala after few years and continued to spread.  Resurgence of malaria  was  due to  many reasons, which include  interstate  and international travel, inadequate environmental sanitation, import of cases and mosquitoes  from other states,  migration of increased  number of laborers from  other states, absence of organized preventive public health system in urban areas, urbanization and inadequate filed work.

Result: Active and passive surveillance form important components in malaria eradication and control programmes.  Case detection rate in active surveillance was less than 0.2 % and in mass and contact survey it was less than 0.05%.

Number of malaria cases  and deaths have increased over the past few decades. About 3·2 billion people, more than half the world’s population, are at risk of infection. Globally there are between 350 million  and  500  million  clinical  cases  each  year resulting  in 1 million deaths.1 Although malaria remains an important health problem in some parts of Asia and South America, its main impact is in sub­ Saharan Africa  where at least 90%  of deaths from malaria occur.

The principal vectors, which cause malaria in most parts of India, are the Anopheles culicifacies in rural areas, An. stephensi in urban areas and An. fluviatilis in hilly-forested  areas. Presently malaria is endemic in the central, south eastern and north eastern  parts of  the country.  However in the year  1998, about 20,000 people  and an estimated  577,000 DALYs (disability-adjusted life years) were  lost  due  to malaria in India.2

Materials and Methods

Secondary  data on  malaria  was  collected from the various reports and registers of Directorate of Health  Services and Directorate of Medical Education from 1956 to 2006. The information was also collected form libraries and internet. The data collected from the reports were cross checked with published survey reports  and books. The collected data was entered in excel and analyzed using standard statistical methods.

Results

National Malaria Control  Programme 1953-1958

Figure-1.-Amount--of-DDT-used-for-spraying--in-the-initial-phase--of-the--programme

Figure 1. Amount of DDT used for spraying in the initial phase of the programme

National Malaria control programmes was launched in April  1953 and main activity was indoor residual spraying with DDT twice a year in endemic areas.1 First  control  unit  was  established  in  1953  at Trivandrurn and second unit in 1955 at Thrissur.2 One more control  unit was established  in Malabar area later.  More over  there  were special  schemes  for highly endemic areas like Malampuzha, Nilambur and Wayanad. There were about 9 hypoendemic  units and 3.5 hyperendemic  units under malaria control units. In hypoendemic areas malaria transmission is low  and  malaria  is  not  an  important problem. However  in hyperendemic areas  transmission is intense, but seasonal.

DDT has been used extensively for spraying houses and other structures d wing this period. BHC was also used for spraying to a lesser extends. Total number of structures/ houses sprayed was 5 lakh in 1958-59  and increased  to 45 lakhs  in 1961-62.  In Kerala, malaria cases decreased  from 46216 cases in 1955 to 7481  cases in 1958. At the national level mal aria cases declined from 75 million cases in 1953 to2million cases in 1958.

Figure-2.-Trend-of-malaria--during--the--Last-50--years

Figure 2. Trend of malaria during the Last 50 years

National Malaria Eradication Programme 1958-1977

In 1 958 Government  of India changed  the strategy  from  control  to eradication  and launched National  Malaria Eradication Programme. The malaria eradication programme was very successful in the initial phase and total number of malaria cases fell to 50,000 in 1961.

Simultaneously  the eradication programme was launched in all districts of Kerala. One separate Malaria  laboratory was started  in 1958 for each of the 9  hypo  Endemic   units  apart,  from central laboratory.  In 1960 two more hypo endemic malaria units were started  in Kuttipuram and Ambalapuzha. The total area of Kerala was divided into North and South zones. State has been divided in to 333 divisions, which  consist  of  4-5  sections for  the  effective implementation of the programme.   ln 1963 regular DDT spraying was discontinued in the state. There was successful  termination  of Malaria Eradication programme in Kerala in 13.5 malaria u nits. out of 14:5 units. In   l965, Kerala was declared  as first state in India  which  eradicated malaria.  This  successful completion of Malaria Eradication has been judged by absence  of indigenous  cases for last two years from the entire area of the state. The state entered in the maintenance  phase of  the  programme  and regular indoor  residual  spraying  was discontinued except at Sabarigiri Hydro project. Seasonal  DDT spraying continued  in all project areas in 1966. No indigenous cases were detected until 1968, however 14 indigenous cases were detected on 1969.

Table 1. Malaria cases detected by active and passive surveillance

Table 1. Malaria cases detected by active and passive surveillance

Modified  Plan of’ Operation 1977

Modified plan of operation started in Kerala on 1st April 1977 in line with rest of India. This change in strategy was due to resurgence of malaria in most part of India  in spite  of active mosquito  control measures  during  the eradication   programme. As Annual Parasite Index (API) in Kerala was less than 2  and  no  indigenous Plasmodium falciparam infections were  reported  from  Kerala, regular spraying and focal spraying were discontinued  in State. However from December 1977 on wards focal spraying started in the state irrespective of API status, considering the special epidemiolog1cal situation. A new component, P. falciparum containment, has been introduced in October 1977 for the prevention and containment of falciparum  malaria.

Table 2. Plasmodium species detected

Table 2. Plasmodium species detected

Malaria Action Plan 1994

Malaria action programme  was introduced in  1994 as  per  the  recommendation of “expert committee on malaria” for prediction, early detection and effective response to malaria outbreak at district level.

The  An. stephensi  species which  was  not present in Kerala during the past, entered  the state in nineteen nineties and contributed  to the malaria out break  during 1996 at Valiathura near Thiruvananthapuram airport,  where over 100 cases of  malaria  were  reported. This  was followed by another outbreak in Kasargod during 1998 when 405 cases  and three deaths were  reported.1   New programme  and strategies were not able to prevent the new epidemic  in Kerala.

Discussion

Malaria in Kerala  showed  a cyclical trend with peak  in 20 years. The  incidence  was higher before  1957, before  the formation  of Kerala  state, and with  the  control  measures  indigenous cases reduced  to zero in 1965.  Malaria reemerged  and reached 5782 cases  in 1978  and  then  showed  a downward  trend  for  some  years.  Second   peak occurred about 20 years later, in 1996, with 10506 cases and there after showed a continuous downward trend.

Active and  passive  surveillance form important  components  in malaria  eradication  and control  programmes.  Case detection  rate in active surveillance  was less than 0.2% and in mass and contact survey it was less than 0.05%. The relevance of active surveillance and mass survey is doubtful in the context of low detection  rate. However in the passive surveillance the case  detection  rate  was higher, which is more relevant. To establish effective control, a rigorous assessment of the geographical distribution of the disease is also needed.1   This can be achieved by vector survey and geographical mapping of the vector prevalence. Absences of such reports are largely due to inadequate documentation and publication of data rather than collection of such data.

The preventive health care systems in urban areas are weak, which can be explained by the absence  of organized  primary  health care setup  in urban areas. Similarly due to absence of malaria control programme in  urban areas urban areas are at a high risk for malaria epidemics.2

Control measures usually depend on routine services being instituted and maintained in a long term perspective,  contrast to the eradication where activities are time limited, intensive targeted  and organized in a circumscribed  programme.3  Malaria eradication plan later changed to modified action plan, which focus on control of the malaria rather than eradication.

First global strategy for the malaria eradication was massive application of Dichlorodiphenyltrichoroethane (DDT) to interrupt transmission  of the disease in countries around the world. This approach failed to interrupt transmission completely in many countries and malaria resurged.4 Moreover, vector control measures using insecticides become  ineffective because  of  the  resistance of Anopheles mosquitoes to insecticides and treatment of  Plasmodium  falciparam  mal aria  become  more difficult as  parasites become drug   resistant.5 Moreover  no  vaccine is commercially available against malaria  as malaria parasites are more complex than disease causing viruses and bacteria.6  It i s less chance  to develop  an  effective vaccine against Malaria in the near future. Life cycle of plasmodium is complex,  which encompasses several  stages in mosquito and humans. A vaccine effective in killing one  stage  may not inhibit  the growth  of another. However conventional  control measure like source reduction,  anti larval   measures and  personal protection are effective.  Malaria was eliminated from the United States  and from most of Europe during the first half of the twentieth century as a result of changes in land use, agricultural practices and house construction and targeted vector control.7

The causes of resurgence of malaria in Kerala are rather complex and includes interstate and international travel, inadequate environmental sanitation, import of cases and mosquitoes from other states, migration  of increased  number  of  laborers from other states, absence of organized preventive public health system in urban areas, urbanization and inadequate filed work. Lack of flexibility and regional level planning in the malaria control programme adversely affected the implementation at peripheral level.

Conclusion

Highly developed levels of sanitation and health systems development  may make elimination of a disease feasible  in one geographical  area  but not in another. Secondary transmission from imported cases  will continue to occur even after elimination has  been  achieved.8  This is due to interstate and international travel and also rarely due to import of infected mosquitoes from other endemic regions.

Eradication of many diseases like malaria was unsuccessful during  the past.  However  they contributed greatly to a better understanding of the biological, social, political and economical complexities of achieving the ultimate goal in the disease control.9 More over all malaria eradication programme is able to control  the transmission  to a great  extend  and eliminate the disease  from man y parts of the state temporally.   Integrated  mosquito  control  measures not only eliminate malaria from the state but also control of other mosquito born diseases like Dengue fever, Chikungunia  and Filariasis.

End Note

Author Information

Dr K Sandeep, MPH, Assistant Surgeon,
Health Services Department, DHS Office, Trivandrum. E-mail: sandeepkerala@hotmail.com

Conflict of Interest: None declared

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