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Malaria risk rises with repatriates: Anti Malaria Campaign

As repatriated individuals who could be returning from malaria endemic countries are being accommodated at quarantine centres in areas where malaria is endemic, the risk of the spread of malaria has risen in the country, The Morning learnt.

Speaking to The Morning yesterday (26), Anti Malaria Campaign Director Dr. Prasad Ranaweera said that if people who come to Sri Lanka from malaria endemic countries would be in areas which were previously malaria endemic areas for more than two weeks after returning to the country, this would increase the risk of the spread of the disease due to the possible prevalence of vector mosquitoes.

“If travel restrictions are put in place, the risk would be less but with a lot of people returning to the country and staying in areas where malaria used to be prevalent – the Dry Zone – this increases the risk of malaria spreading in the country.”

Dr. Ranaweera said that as solutions, a two kilometre (km) radius of the quarantine centres is cleared for malaria before a quarantine centre is established. “We only use the quarantine centre if malaria mosquitoes are not detected,” he said.

Apart from this, quarantine centres are also testing the travellers for malaria before they are discharged from the quarantine centres. The Anti Malaria Campaign follows up on these individuals in three months, six months, up to one year.

Last year, a total of 30 cases of imported malaria were detected in the country and 11 of those were detected from quarantine centres. Out of all the cases, five cases had been from India and the rest were from the African region.

This year has recorded seven imported cases so far and they have been from patients who arrived from the African region. Only one case has been detected from quarantine centres.

Sri Lanka has been certified by the World Health Organisation (WHO) as a country that has successfully eliminated malaria, as the last local case had been detected in 2012. However, Sri Lanka has only eliminated the parasite and has not eliminated the vector Anopheles mosquito.

“Since we can’t eliminate the mosquito, when a person comes from a malaria endemic country, the vector gets the opportunity to establish the transmission again,” said Dr. Ranaweera.

The malaria parasite can be hidden in the liver for nearly a year. If the parasite enters the blood circulation at any point during that year, the parasite can be transmitted when a malaria mosquito bites.

The strategy of the Campaign is to track a person who arrives in the country from a malaria endemic country before the mosquito does bite, Dr. Ranaweera said.

“Since we can’t screen all the people coming from endemic countries, we educate the public returning from such countries to inform the relevant doctor if they have fever and to inform also that they have come from a malaria endemic country. The problem is that sometimes patients don’t tell that they came from a malaria endemic country and the doctors also forget to ask about the travel history.”

In 2017, a mosquito that is a key vector in urban malaria – Anopheles stephensi – was detected in the Mannar District and subsequently in Vavuniya, Jaffna, and Kalmunai. This mosquito is said to show resistance to insecticides. “We usually don’t kill mosquitoes but we have changed that strategy for this mosquito. We want to eradicate this mosquito. We have closed a number of abandoned wells in these areas to destroy the breeding grounds,” Dr. Ranaweera said.

It would pose a challenge to the prevention of malaria if this mosquito spreads to Colombo because 50% of the imported cases of malaria are detected from the Colombo District, he added.