Should chemoprophylaxis be a main strategy for preventing re-introduction of malaria in highly receptive areas? Sri Lanka a case in point

Abstract

BackgroundImported malaria cases continue to be reported in Sri Lanka, which was declared ‘malaria-free’ by the World Health Organization in September 2016. Chemoprophylaxis, a recommended strategy for malaria prevention for visitors travelling to malaria-endemic countries from Sri Lanka is available free of charge. The strategy of providing chemoprophylaxis to visitors to a neighbouring malaria-endemic country within the perspective of a country that has successfully eliminated malaria but is highly receptive was assessed, taking Sri Lanka as a case in point.MethodsThe risk of a Sri Lankan national acquiring malaria during a visit to India, a malaria-endemic country, was calculated for the period 2008–2013. The cost of providing prophylaxis for Sri Lankan nationals travelling to India for 1, 2 and 4 weeks was estimated for that same period.ResultsThe risk of a Sri Lankan traveller to India acquiring malaria ranged from 5.25 per 100,000 travellers in 2012 to 13.45 per 100,000 travellers in 2010. If 50% of cases were missed by the Sri Lankan healthcare system, then the risk of acquiring malaria in India among returning Sri Lankans would double. The 95% confidence intervals for both risks are small. As chloroquine is the chemoprophylactic drug recommended for travellers to India by the Anti Malaria Campaign of Sri Lanka, the costs of chemoprophylaxis for travellers for a 1-, 2- and 4-weeks stay in India on average are US$ 41,604, 48,538 and 62,407, respectively. If all Sri Lankan travellers to India are provided with chemoprophylaxis for four weeks, it will comprise 0.65% of the national malaria control programme budget.ConclusionsBased on the low risk of acquiring malaria among Sri Lankan travellers returning from India and the high receptivity in previously malarious areas of the country, chemoprophylaxis should not be considered a major strategy in the prevention of re-introduction. In areas with high receptivity, universal access to quality-assured diagnosis and treatment cannot be compromised at whatever cost.

Prevention of re-establishment of malaria

“…Chemoprophylaxis for travellers should reduce the risk of importation of malaria cases. Yet, the effect in relation to risk of re-establishment of transmission may be limited, because the traveller returning to a malaria-free country may be less likely than a job-seeker from an endemic country to stay in a receptive area under conditions conducive to transmission [ 14 ]. For travellers to countries, which are endemic for vivax malaria, there is again the problem of hypnozoites, which are not killed by most of the medicines used for chemoprophylaxis.…”

Response of imported malaria patients to antimalarial medicines in Sri Lanka following malaria elimination

“…A large proportion of these travelers departs to and returns from India, which has endemic malaria transmission. In year 2013, approximately 500,000 individuals crossed the borders of these two countries and it is a 37.5% increase compared to 2008[ 30 ]. Comparatively, a much smaller exchange occurs between African countries and Sri Lanka.…”