Malaria elimination in Bhutan: asymptomatic malaria cases in the Bhutanese population living in malaria-risk areas and in migrant workers from India

Background Many malaria endemic countries are heading towards malaria elimination through the use of case management and vector control strategies, which employ surveillance, improving access to early diagnosis, prompt treatment., and integrated vector control measures. There is a consensus that elimination of malaria is feasible when rapid detection and prompt treatment is combined with mosquito-human contact interruption in an efficient and sustainable manner at community levels. This paper describes results of an integrated case management and vector control strategy for reducing malaria cases in 1233 villages over 3 years in district Mandla, Madhya Pradesh, India. Methods The project enrolled the entire population (1,143,126) of Mandla district for fever surveillance followed by testing of febrile cases and treatment of positive subjects using T4 strategy, which is Track (by fever), Test (by RDTs), Treat (by ACT) and Track (for completion of treatment). In addition to the active and passive surveillance for detection and treatment of febrile cases, the project conducted mass screening and treatment to clear the asymptomatic reservoirs of infection. Febrile cases were also tested in the out-patient department of the District Hospital from June 2018 to September, 2018 and in a community-based medical camp from November 7 to 14, 2019. The project also used vector control measures for interrupting human-mosquito contact, and information, education and communication (IEC) campaigns to increase demand for malaria services at community level. Results This project has revealed about 91% reduction of indigenous cases of malaria during the period from June 2017 to May 2020, through case management and vector control strategies. A total 357,143 febrile cases were screened, out of which 0.19% were found positive for the presence of malaria parasites, with Plasmodium falciparum and Plasmodium vivax ratio of 62:38. The prevalence of malaria was higher in individuals > 15 years of age (69% cases). The positivity rate was 0.33% in 2017–18, 0.13% in 2018–19, and 0.06% in 2019–20. In all of the 3 years of the project, the peak transmission correlated with rains. Mass screening revealed 0.18% positivity in Sep-Oct 2018, followed by 0.06% in June 2019, and 0.03% in December 2019, and these were mostly asymptomatic cases in the community. Imported cases into the district were mostly contributed by the distant state of Telangana (51.13%). Fever patients tested for malaria parasites in the District Hospital and medical camp revealed zero cases. Conclusion Using the current intervention and prevention tools along with optimum utilization of human resources, a 91% reduction in indigenous cases of malaria was seen in the district in 3 years. The reduction was similar in the three high prevalence blocks of the district. These results reveal that malaria elimination is achievable in India within a stipulated time frame. The reduction of malaria at the community level was further validated when zero malaria cases were diagnosed during hospital and community-based studies in Mandla. Prompt detection and treatment of imported/migratory cases may have prevented outbreaks in the district. This project has demonstrated that field programmes backed by adequate technical, management, operational, and financial controls with robust monitoring are needed for achieving malaria elimination.

Section: Discussionmentioning

confidence: 99%

Demonstration of indigenous malaria elimination through Track-Test-Treat-Track (T4) strategy in a Malaria Elimination Demonstration Project in Mandla, Madhya Pradesh

Bharti

Rajvanshi²,

Nisar³

et al. 2020

“…This is that with massive developmental projects underway in most countries, there is rampant human movement, largely by way of migrant labour between these countries. Those countries in Asia that are now eliminating malaria, such as Timor Leste, Bhutan and Nepal, are in the tropical belt and they remain highly vulnerable to the re-establishment of malaria due to the presence of malaria vectors, and groups of migrant labour who move freely between them and their neighbouring countries (Indonesia and India respectively) with ongoing transmission [ 20 – 22 ]. They often reside in the recipient country for several months offering a continuous source of parasites.…”

Section: Discussionmentioning

confidence: 99%

Mass radical treatment of a group of foreign workers to mitigate the risk of re-establishment of malaria in Sri Lanka

Marasinghe

Karunasena²,

Seneratne

et al. 2020

Background Following malaria elimination, Sri Lanka was free from indigenous transmission for six consecutive years, until the first introduced case was reported in December 2018. The source of transmission (index case) was a member of a group of 32 migrant workers from India and the location of transmission was their residence reporting a high prevalence of the primary vector for malaria. Despite extensive vector control the situation was highly susceptible to onward transmission if another of the group developed malaria. Therefore, Mass Radical Treatment (MRT) of the group of workers for Plasmodium vivax malaria was undertaken to mitigate this risk. Method The workers were screened for malaria by microscopy and RDT, their haemoglobin level assessed, and tested for Glucose 6 phosphate dehydrogenase deficiency (G6PD) using the Care Start RDT and Brewers test prior to treatment with chloroquine (CQ) 25 mg/kg body weight (over three days) and primaquine (PQ) (0.25 mg/kg/day bodyweight for 14 days) following informed consent. All were monitored for adverse events. Results None of the foreign workers were parasitaemic at baseline screening and their haemoglobin levels ranged from 9.7–14.7 g/dl. All 31 individuals (excluding the index case treated previously) were treated with the recommended dose of CQ. The G6PD test results were inconclusive in 45% of the RDT results and were discrepant between the two tests in 31% of the remaining test events. Seven workers who tested G6PD deficient in either test were excluded from PQ and the rest, 24 workers, received PQ. No serious adverse events occurred. Conclusions Mass treatment may be an option in prevention of reintroduction settings for groups of migrants who are likely to be carrying latent malaria infections, and resident in areas of high receptivity. However, in the case of Plasmodium vivax and Plasmodium ovale, a more reliable and affordable point-of-care test for G6PD activity would be required. Most countries which are eliminating malaria now are in the tropical zone and face considerable and similar risks of malaria re-introduction due to massive labour migration between them and neighbouring countries. Regional elimination of malaria should be the focus of global strategy if malaria elimination from countries is to be worthwhile and sustainable.

“…In the last decade, Bhutan pursued a successful and sustained malaria elimination programme. This has led to a low incidence of malaria that is compatible with elimination programme [ 3 ]. The malaria cases have dwindled to just two indigenous cases in 2019 [ 4 ].…”

Section: Introductionmentioning

confidence: 99%

Has COVID19 derailed Bhutan’s national malaria elimination goal? A commentary

Penjor

Tobgyal

Zangpo

et al. 2021

The COVID-19 pandemic has resulted in massive global disruptions with considerable impact on the delivery of health services and national health programmes. Since the detection of the first COVID-19 case on 5th March 2020, the Royal Government of Bhutan implemented a number of containment measures including border closure and national lockdowns. Against the backdrop of this global COVID-19 pandemic response, there was a sudden surge of locally-transmitted malaria cases between June to August 2020. There were 20 indigenous cases (zero Plasmodium falciparum and 20 Plasmodium vivax) from a total of 49 cases (seven P. falciparum and 42 P. vivax) in 2020 compared to just two from a total of 42 in 2019. Over 80% of the cases were clustered in malaria endemic district of Sarpang. This spike of malaria cases was attributed to the delay in the delivery of routine malaria preventive interventions due to the COVID-19 pandemic. As a result, Bhutan is unlikely to achieve the national goal of malaria elimination by 2020.