Irregular migration: malaria re-introduction in elimination settings.

Author(s) Kolitha Wickramage1, Sharika Peiris 2.
Affiliation(s) 1Health Unit, International Organization for Migration, Sri Lanka, Sri Lanka, 2Health Unit, International Organization for Migration, Sri Lanka, Sri Lanka.
Country - ies of focus Sri Lanka
Relevant to the conference tracks Infectious Diseases
Summary Irregular migration in the form of human smuggling and human trafficking is recognized as a global public health issue. Beyond the criminality and human rights abuse, irregular migration plays an important, but often forgotten, pathway for malaria re-introduction. We describe 32 cases of Plasmodium falciparum that were detected in 534 irregular migrants returning to Sri Lanka via failed human smuggling routes from West Africa in 2012, who contributed to the largest burden of imported cases in Sri Lanka which had entered elimination phase. Active surveillance of the growing numbers of irregular migrant flows becomes an important strategy as Sri Lanka advances towards goals of malaria elimination.
Background Sri Lanka is heralded as a ‘success story’ for malaria control in Asia having succeeded in reducing malaria cases
by 99.9% since 1999 and is aiming to eliminate the disease entirely by 2014. Since the end of the protracted civil conflict in 2009, there have been an unprecedented number of migrants leaving Sri Lanka to countries such as Australia, Canada and the UK via ‘irregular migration’ routes. An irregular migrant is defined as someone who, owing to illegal entry or the expiry of his or her visa, lacks legal status in a transit or host country. Irregular migration takes many forms, ranging from human smuggling to trafficking of persons for purpose of exploitation. Globally, the numbers of undocumented cases have increased despite spending on enforcement measures at the major destination countries.
Objectives This report focuses on a migrant flow of major importance for malaria importation that, until recently, has received little attention from public health authorities.
Methodology From the end of 2011, local and international law enforcement authorities intercepted people-smuggling operations from Sri Lanka to Canada across nine West African nations: Togo, Benin, Guinea, Sierra Leone, Mali, Ghana, Senegal, and Mauritania. In close coordination and partnership with the Governments of Sri Lanka, Canada and West African nations, IOM assisted these irregular migrants who were intercepted or detained, and returned to their place of origin. From January to December 2012, all irregular migrants returning from West African countries were subjected to malaria screening upon arrival at the Bandaranayke International Airport (BIA) in Sri Lanka. Screening was conducted on site using the rapid diagnostic test kit CareStart™ Malaria HRP2/PLDH, with 98% sensitivity and 97.5% specificity for Plasmodium falciparum, and microscopic examination of blood smears, collected at the airport and performed at the national reference laboratory. Health personnel from the airport medical unit, Anti-Malaria Campaign (AMC) and IOM officials were involved in facilitating the on-arrival screening process. Under a directive from the Anti-Malaria Campaign, repeat RDTs were carried out for all returnees at the district level within one week of their arrival at home destination. This intensive follow-up was carried out with the collaborative efforts of both the AMC and IOM field staff.
Results Of the total number of returnees screened (n=534), 32 were positive for P. falciparum. Nearly two thirds (n=19) were identified at the point of entry at the BIA and 13 during district level follow-up. The total number of malaria cases from irregular migration routes accounted for 76% (32/42) of the total number of P. falciparum cases detected in Sri Lanka in 2012. This route contributed to 46% (32/70) of the total number of imported malaria cases in the same year. Imported cases overtook indigenously acquired cases of malaria for the first time in Sri Lankan in 2012, contributing to three-quarters of the total malaria burden (70/93). The largest number of irregular migrants (n=17) had returned to Jaffna district which has the highest API of >0.2 to 0.3 in comparison to other districts in Sri Lanka.
Conclusion Malaria incidence in returnees from source countries has proven to be a sensitive predictor of malaria risk, particularly where there is sub-national transmission. The fact that the largest number of migrants returned to districts with the highest API indexes reported nationally is also significant. Re-introduction and risk of spreading the parasites occurs when there is a long-term return into areas of endemicity with presence and prevalence of the mosquito vector. For this reasons the close follow up and monitoring performed by the AMC and IOM field based teams is an important strategy. Unlike other categories of inbound migrants, such as tourists, who may also import malaria to the country, returning Sri Lankan citizens from endemic areas are more likely to be exposed to mosquito bites and hence are more likely to contribute to the spread of malaria upon return to their homes within locally endemic regions. Other inbound migration categories include: returning Sri Lankan labour migrant workers, Sri Lankan armed forces personnel from UN peace keeping missions, and returning students. The attack rate for malaria in this migrant group using irregular modes of travel is considerably high (sixty cases per 1,000) when compared to the risk of contracting malaria for regular travellers returning from West Africa at three per 1,000. For the migrants themselves, their ‘illegal’ status and clandestine nature of movements enhanced health vulnerability, including having little or no access to health care in transit countries.

, , , , ,

No comments yet.

Leave a Reply