PANAJI
As Goa is on its journey towards malaria elimination after zero indigenous cases in 2023, the increasing number of imported-malaria cases, due to scores of migrants or labour class from the malaria-endemic North-Central, Eastern and North-Eastern States, is looked as a major threat in the progress of eradicating the vector-borne disease with experts warning of its possible resurgence.
According to health experts, being an international tourist destination, Goa is an important source of imported malaria to travellers from Europe, too.
As per the recent study, for the first time in the last two decades, Goa reported zero indigenous malaria cases in 2023. However, the imported cases have more than doubled from 585 in 2022 to 1,209 in 2023. With increasing construction activities and dominance of migrant labour class, areas like Panaji, Aldona, Porvorim, Betqui, Candolim, and Siolim in North Goa, and South Goa’s Margao have become clusters of high imported malaria cases.
More so, from 2012–2021, the patients’ profile at GMC shows that 10 per cent of the cases are malaria-positive within one month of their arrival to Goa, indicating substantial local transmission among migrant workers.
These were the findings of a joint study undertaken by health experts from the Goa Directorate of Health Services, National Institute of Malaria Research and the Department of Public Health and Community Medicine, Central University of Kerala.
“In the last decade, indigenous malaria transmission in Goa has declined steeply, and the state appears to be on track to achieve its goal of malaria elimination. Despite the steep decline in indigenous cases, imported malaria cases continue to rise in recent years, indicating the continuous arrival of high-risk groups positive for malaria,” the study revealed.
According to the experts, as Goa’s beaches attract millions of domestic and international travellers every year and to sustain tourism in Goa, scores of migrants are employed in construction activities throughout the year.
“The high demand and wages attract migrants from socioeconomically disadvantaged states to Goa to the construction industry and to a lesser extent to the hospitality sector. The imported malaria cases are largely attributable to the migrant construction workers,” they said.
The study says that more than half of the malaria-positive cases in Goa Medical College (GMC) were migrant construction workers from the malaria-endemic north-central, eastern and northeastern states. “GMC showed a steep decrease in parasitaemia from 2% in 2012 to 0.35% in 2021, while the gametocyte density has increased from 146 to 385/uL, suggesting an increasing trend towards sub-microscopic infections and transmission commitment, characteristic of low-transmission settings,” it added.
In addition to the risk of local malaria transmission, these migrant workers can also introduce drug-resistant malaria parasites from NE, especially parasites resistant to sulfadoxine-pyrimethamine (SP), to the urban centres of Goa, the experts said.
“As the malaria cases decrease in the local population, there will be a decrease in protective immunity, and local outbreaks could lead to severe symptoms,” the study said.
Experts opine that continuous active surveillance, early detection and prompt treatment of migrant workers and vulnerable local population, and sustaining the ongoing parasite and vector control strategies, are key to maintaining the malaria-free status in Goa.
The study points out that though Goa Public Health Act (1985), mandates contractors to screen the hired migrants for malaria by rapid diagnostic test (RDT) or microscopy at the local PHC so that a health card can be prepared within 24-48 hours after their arrival in Goa, a major limitation of malarial screening by RDT or microscopy is they cannot detect sub-microscopic infections with very low levels of parasites.
