First case of Plasmodium knowlesi infection in a Japanese traveller returning from Malaysia

Ryutaro Tanizaki,Shuzo Kanagawa,Mugen Ujiie,Shigeyuki Kano,Satoshi Kutsuna,Kayoko Hayakawa,Norio Ohmagari,Moritoshi Iwagami,Nozomi Takeshita,Yasuyuki Kato,Aki Hashimoto

doi:10.1186/1475-2875-12-128

Ryutaro Tanizaki, Shuzo Kanagawa + Show 9 more

Open Access

https://doi.org/10.1186/1475-2875-12-128

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Journal: Malaria journal	Publication Date: Apr 15, 2013
Citations: 53	License type: CC BY 2.0

Affiliation: National Center for Global Health and Medicine

Abstract

This is the first case of Plasmodium knowlesi infection in a Japanese traveller returning from Malaysia. In September 2012, a previously healthy 35-year-old Japanese man presented to National Center for Global Health and Medicine in Tokyo with a two-day history of daily fever, mild headaches and mild arthralgia. Malaria parasites were found in the Giemsa-stained thin blood smear, which showed band forms similar to Plasmodium malariae. Although a nested PCR showed the amplification of the primer of Plasmodium vivax and Plasmodium knowlesi, he was finally diagnosed with P. knowlesi mono-infection by DNA sequencing. He was treated with mefloquine, and recovered without any complications. DNA sequencing of the PCR products is indispensable to confirm P. knowlesi infection, however there is limited access to DNA sequencing procedures in endemic areas. The extent of P. knowlesi transmission in Asia has not been clearly defined. There is limited availability of diagnostic tests and routine surveillance system for reporting an accurate diagnosis in the Asian endemic regions. Thus, reporting accurately diagnosed cases of P. knowlesi infection in travellers would be important for assessing the true nature of this emerging human infection.

Highlights

The first naturally acquired zoonotic infection with Plasmodium knowlesi in a human was reported in 1965 [1]; thereafter, no such infections were reported for almost 40 years
To make a definitive diagnosis, two partial gene regions from five malaria parasite species were tried to be amplified by nested PCR, using respective primer sets for P. falciparum, Plasmodium vivax, Plasmodium ovale, P. malariae and P. knowlesi
Most P. knowlesi infections are reported in the rural jungle areas of the Malaysia peninsular and in Borneo (Sabah [17] and Sarawak [2] province) where both of the infectious hosts and vectors (Anopheles mosquitoes) predominantly exist

Summary

Introduction

The first naturally acquired zoonotic infection with Plasmodium knowlesi in a human was reported in 1965 [1]; thereafter, no such infections were reported for almost 40 years. In 2004, Singh et al [2] reported that natural P. knowlesi infections in humans were common parasite species in Malaysia. 12 cases of P. knowlesi infection in travellers have been reported from nonmalaria endemic countries far [1,4,5,6,7,8,9,10,11,12,13,14].

Results

Conclusion