Imported malaria infections pose a continuing threat of re-establishing malaria transmission in Sri Lanka owing to the high prevalence of mosquito vectors in the country [3]. The country has been kept free of indigenous transmission during the 8 years since elimination except for a single case of introduced malaria reported in 2018 [5]. Sri Lanka has, so far, also fared well in the COVID-19 epidemic. As of 16 October 2020 there have been 5244 COVID-19 cases as reported from 365,859 real-time PCR tests performed in the country, and only 13 deaths in a population of 21 million [6].
The COVID-19 response in Sri Lanka has been one of testing for SARS-CoV-2 infection, rigorous contact tracing and quarantining, combined with mandatory wearing of facemasks, social distancing, and strict personal hygiene, after the 2-month lockdown was eased. Sri Lanka’s health system comprises 1.004 physicians per 1000 people. Contact tracing and quarantining requires an enormous effort on the part of health workers and is a heavy burden of work on the health system, and this was shared equally between the Ministry of Health and the Police Department and the military whose expertise and resources were rapidly mobilized.
The strategies of surveillance, contact tracing and testing have also been the core components of the POR programme for malaria. Since 2012, imported malaria patients and their travel contacts have been actively searched out by the Anti Malaria Campaign (AMC) and the Regional Malaria Officers, tested and treated to prevent the onward spread of their infections [3, 7]. Despite these commonalities, the staff, resources and expertise of the malaria programme were not mobilized for the COVID-19 response in Sri Lanka to any significant extent. However, several senior public health policy makers who were involved in the planning and implementation of the COVID-19 response have spoken out that their malaria elimination experience served them extremely well in planning for the COVID-19 epidemic. More specifically, their past experiences with investigating a case of malaria at the local level to ascertain where mosquito transmission may have occurred by tracing the movements of the person, and screening those who might have been similarly exposed to malaria by blood examination, and thereafter taking action at the local level, such as by focal vector control to prevent further transmission were, they said, principles which they have adopted in the COVID-19 response. They also said that appreciating the value of public health workers at the ground level in case investigation and local malaria control, and the importance of mounting coordinated responses were experiences they gained from malaria. What has also been remarkable from the beginning of the COVID-19 epidemic was the very efficient networking and highly organized and well coordinated operations between units of the Ministry of Health and other sectors whose inputs have been critical to the success of the programme—the Ministries of Defense, Airport and Aviation, Foreign Affairs, and the Police Department, all of which came under the umbrella of a Presidential Task Force for COVID-19 control.
Interactions between the two diseases, malaria and COVID-19 were many: the closure of the airport except for the repatriation of Sri Lankan nationals who were stranded overseas, was expected to be a respite for the malaria programme because of reduced traffic from overseas and, therefore, could have reduced number of imported malaria entering the country, but this was not to be. Many Sri Lankan returnees from overseas were from malaria endemic countries—Africa, the Middle East and India, which placed the country at high risk of importing malaria infections.
The repatriation of Sri Lankan nationals from overseas during the COVID-19 pandemic entailed them being flown back by the national airline, testing at the airport, immediate dispatch to quarantine centres for 2 weeks followed by a supervised self-quarantine in their homes for a further 2 weeks. This programme was coordinated between the Departments of Airports and Aviation, the Ministry of Defense (the Army, Air force and Navy), Ministries of Foreign Affairs, and Health. When Sri Lankan nationals are being flown into the country in batches during the current COVID-19 epidemic the Anti Malaria Campaign (AMC) is being informed by the relevant units of the COVID-19 programme of all details ahead of their arrival, including which countries they are arriving from, and the location of their to-be quarantine centres. If they happen to come from a malaria endemic country the AMC and the Regional Malaria Officers ensure that they are screened for malaria regardless of symptoms, by microscopic blood examination, once while in quarantine at around day 10 when blood is being taken for COVID-19 testing. In the post-quarantine period, they are followed-up with blood screening for malaria by microscopy at 3, 6 and 12 months when they return to their homes and they are advised to report for malaria testing if they develop fever. If and when a patient develops fever whilst in quarantine they are tested promptly for malaria. Furthermore, if the quarantine centre is located in a previously malaria endemic area, where there is a risk of malaria being transmitted, an entomological survey is conducted around the quarantine centre, and if malaria vectors are found, a pre-emptive vector control programme is implemented promptly. Accordingly entomological surveys have been conducted in quarantine centres located in 18 of the 25 districts in the country. Of a total of 80 such surveys, 17 surveys captured Anopheles culicifacies, the primary vector of malaria, which required vector control measures to be taken. Forty-four and 46 of these surveys captured secondary Anopheline vectors of malaria and non-vector Anopheline species respectively.
The AMC had cultivated close working relationships with the military and the Police Departments in the past during the elimination and post-elimination phases because their members were at a high risk of acquiring malaria, either in Sri Lanka during the civil war, or later while overseas on UN peacekeeping missions [8, 9]. These collaborations served well during the COVID-19 epidemic in which the military and the Police have been playing a major role.
Since the beginning of the COVID-19 epidemic in Sri Lanka a significant number of returnees from overseas developed malaria infections while they were in quarantine for COVID-19. A total of 23 imported malaria cases were detected from February to October through 2773 microscopic blood examinations performed for malaria in quarantine centres, this number being not much different to the incidence of imported malaria during the same period last year (n = 34). However, returnees from overseas being confined to quarantine centres (for COVID-19) made it all the more easier for the Anti Malaria Campaign to locate, screen and treat them promptly for malaria.