Malaria in Kerala: Lessons from Goa

Malaria in Kerala: Lessons from Goa

Another World Malaria Day was observed throughout the world on 25^th April. Malaria still continues to be one of the major infectious diseases, especially in low income countries, with about 219 million cases and 0.7 million deaths annually.

In Kerala malaria is generally considered as a disease of the past. However, there has been a consistent increase in the reported number of malaria cases in recent years. Officially malaria was eradicated from the state in 1965. However, within a few years the disease returned to the state, although not as strong as in the pre-eradication era. The current problem appears to be related to aggregations of migrant workers related to the booming construction industry. According to a report published in Times of India on 22^nd April 2013 nine malaria cases were detected from construction workers in Calicut. The most alarming aspect of the report was that 2 of the nine persons with the infection were Keralites. Obviously, they acquired the disease from the migrant workers who came from malaria endemic states. Hence, the present problem of malaria in Kerala can be classified as urban malaria related to construction industry.

The above situation has very close similarities with the origin and proliferation of malaria in Goa.  Perhaps our state can learn a few lessons from the Goan experience and plan control strategies well in advance. Like Kerala, malaria was eradicated from Goa in 1965. Goa was the second state in India after Kerala to eradicate malaria. In both the states malaria in pre-eradication era was almost restricted to the eastern hilly areas. The vector mosquito was the same in both states-Anopheles fluviatilis.  This mosquito prefers to breed in slow running streams in forested areas, which was eliminated by continuous application of DDT and also by the elimination of breeding sites by deforestation!  

In 1985 a few cases of malaria were reported from the capital city Panaji. The cases were detected from migrant workers who were brought in connection with the construction of an aquatic complex in the capital. The episode did not attract any special interest from the concerned authorities. However, in the following years malaria started increasing and reached epidemic proportions by 1986.  The local health authority was incapable of dealing with the situation and requested Indian Council of Medical Research to intervene. In 1989 Malaria Research Centre (MRC) opened its field station in Panaji to study the problem and offer solutions (The author joined MRC in 1991). The MRC’s study revealed that the epicenters of malaria outbreaks in the town were construction sites. They provided all favourable conditions for the proliferation of malaria. Malaria is a disease caused by microscopic organisms called Plasmodium, which completes its life cycle in man and mosquito. In man, plasmodia initially enter liver cells and multiply and subsequently enter Red Blood Corpuscles. When the right kind of mosquitoes feed such infected blood the parasites enter the mosquito tissue and complete their life cycle.  Malaria parasites can survive only inside Anopheles mosquitoes. In Goa the mosquito species responsible for malaria transmission was Anopheles stephensi.  They prefer to breed in man- made breeding habitats like cement tanks, wells, over head tanks etc. In Panaji their profuse breeding was observed in stagnant water deliberately kept for curing purpose inside the buildings under construction. Besides, migrant workers stayed in small huts next to the buildings under construction. This situation provided ample opportunities to the mosquitoes to pick up the parasites and transmit to the people around. MRC launched mosquito control using fishes and bacterial toxin and also opened a malaria clinic for the fast diagnosis and treatment of malaria cases. Besides, screening of migrant workers for malaria was done regularly.  The results were amazing and malaria was brought under control. However, subsequent to the transfer of technology to the state Government malaria returned, obviously due to complacence.    

There is every possibility that the experience of Goa could be repeated in Kerala owing to identical conditions prevalent in the state, i.e. rampant construction activities and aggregation of migrant workers from malaria endemic states. If fool proof strategies are adopted right now future malaria outbreaks in the state could be prevented. In fact, the theme of this year’s World Malaria Day is ‘Invest in the future. Defeat malaria’.  A multi prong strategy is the need of the hour. The components of the strategy can be summarized as below:

1. Screening the migrant workers for malaria on the day of their arrival and also once in a fortnight.
2. Mosquito control in the construction sites, especially cement tanks and curing water (water kept inside buildings under construction).
3. Make all the stakeholders in the construction industry aware of malaria.
4. For the purpose of early detection of cases newly available diagnostic kits may be used.
5. The cost of malaria control in construction sites may be recovered partially from the construction firms.

Dr.P.K. Sumodan

Assistant Professor of Zoology

Government College, Madappally, Vadakara

(Formerly: Scientist, Malaria Research Centre, Goa; District Malaria Officer, Wayanad)