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. 2020 Jan 16;70(3):361-367.
doi: 10.1093/cid/ciz237.

Plasmodium knowlesi Malaria in Sabah, Malaysia, 2015-2017: Ongoing Increase in Incidence Despite Near-elimination of the Human-only Plasmodium Species

Daniel J Cooper  1   2 , Giri S Rajahram  2   3   4 , Timothy William  5 , Jenarun Jelip  6 , Rashidah Mohammad  4 , Joseph Benedict  2 , Danshy A Alaza  2 , Eva Malacova  7 , Tsin W Yeo  8 , Matthew J Grigg  1   2 , Nicholas M Anstey  1   2 , Bridget E Barber  1   2   7
Affiliations

Plasmodium knowlesi Malaria in Sabah, Malaysia, 2015-2017: Ongoing Increase in Incidence Despite Near-elimination of the Human-only Plasmodium Species

Daniel J Cooper et al. Clin Infect Dis. .

Abstract

Background: Malaysia aims to eliminate malaria by 2020. However, while cases of Plasmodium falciparum and Plasmodium vivax have decreased substantially, the incidence of zoonotic malaria from Plasmodium knowlesi continues to increase, presenting a major challenge to regional malaria control efforts. Here we report incidence of all Plasmodium species in Sabah, including zoonotic P. knowlesi, during 2015-2017.

Methods: Microscopy-based malaria notification data and polymerase chain reaction (PCR) results were obtained from the Sabah Department of Health and State Public Health Laboratory, respectively, from January 2015 to December 2017. From January 2016 this was complemented by a statewide prospective hospital surveillance study. Databases were matched, and species was determined by PCR, or microscopy if PCR was not available.

Results: A total of 3867 malaria cases were recorded between 2015 and 2017, with PCR performed in 93%. Using PCR results, and microscopy if PCR was unavailable, P. knowlesi accounted for 817 (80%), 677 (88%), and 2030 (98%) malaria cases in 2015, 2016, and 2017, respectively. P. falciparum accounted for 110 (11%), 45 (6%), and 23 (1%) cases and P. vivax accounted for 61 (6%), 17 (2%), and 8 (0.4%) cases, respectively. Of those with P. knowlesi, the median age was 35 (interquartile range: 24-47) years, and 85% were male.

Conclusions: Malaysia is approaching elimination of the human-only Plasmodium species. However, the ongoing increase in P. knowlesi incidence presents a major challenge to malaria control and warrants increased focus on knowlesi-specific prevention activities. Wider molecular surveillance in surrounding countries is required.

Keywords: elimination; epidemiology; incidence; knowlesi; malaria.

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Figures

Figure 1.
Figure 1.
Map of districts of Sabah. The inset shows the Southeast Asia region with the location of Sabah highlighted.
Figure 2.
Figure 2.
Cases of Plasmodium knowlesi, Plasmodium falciparum, and Plasmodium vivax in Sabah from 2007 to 2017. Data from 2007 to 2014 have been reported previously [6–8].
Figure 3.
Figure 3.
Incidence rate of Plasmodium knowlesi by district, 2013–2017. The key indicates P. knowlesi cases per 1000 persons.
Figure 4.
Figure 4.
Plasmodium knowlesi age distribution, 2015–2017, in males (A) and females (B).
See this image and copyright information in PMC

Comment in

References

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