Plasmodium knowlesi

Taxobox
color = khaki
name = "Plasmodium knowlesi"
regnum = Protista
phylum = Apicomplexa
classis = Aconoidasida
ordo = Haemosporida
familia = Plasmodiidae
genus = "Plasmodium"
species = "P. knowlesi"
binomial = "Plasmodium knowlesi"
binomial_authority =

"Plasmodium knowlesi" is a primate malaria parasite commonly found in Southeast Asia. It causes malaria in long-tailed macaques ("Macaca fascicularis"), but it may also infect humans, either naturally or artificially.

Epidemiology

Reports of human "P. knowlesi" infections are confined to Southeast Asia, [cite journal | author=Chin W, Contacos PG, Coatney RG, Kimbal HR. | journal=Science | year=1965 | title=A naturally acquired quotidian-type malaria in man transferable to monkeys | volume=149 | pages=865 | pmid=14332847 | doi=10.1126/science.149.3686.865 ] [cite journal | journal=Trans R Soc Trop Med Hyg | year=1971 | volume=65 | issue=6 | pages=839–40 | title=A presumptive case of naturally occurring "Plasmodium knowlesi" malaria in man in Malaysia | author=Yap FL, Cadigan FC, Coatney GR. | pmid=5003320 | doi=10.1016/0035-9203(71)90103-9 ] particularly Malaysia,cite journal | journal=Lancet | year=2004 | volume=363 | pages=1017–24 | title=A large focus of naturally acquired "Plasmodium knowlesi" infections in human beings | author=Singh B, Lee KS, Matusop A, Radhakrishnan A, Shamsul SSG, Cox-Singh J, Thomas A, Conway DJ | doi=10.1016/S0140-6736(04)15836-4 ] but there are also reports on the Thai-Burmese border. [cite journal | journal=Emerg Infect Dis | year=2004 | volume=10 | issue=12 | pages=2211–3 | title=Naturally acquired "Plasmodium knowlesi" malaria in human, Thailand | author=Jongwutiwes S, Putaporntip C, Iwasaki T, Sata T, Kanbara H. | pmid=15663864 ] A fifth of the cases of malaria diagnosed in Sarawak, Malaysian Borneo are due to "P. knowlesi".

"P. knowlesi" infection is normally considered an infection of long-tailed ("Macaca fascicularis") and pig-tailed ("Macaca nemestrina") macaques, but humans who work at the forest fringe or enter the rainforest to work are at risk of being infected with "P. knowlesi". The mosquito "Anopheles latens" is attracted to both macaques and humans and has been shown to be the main vector transmitting "P. knowlesi" to humans in the Kapit Division of Sarawak, Malaysian Borneo"cite journal | author=Vythilingam I, Tan CH, Asmad M, Chan ST, Lee KS, Singh B. | title=Natural transmission of "Plasmodium knowlesi" to humans by "Anopheles latens" in Sarawak, Malaysia | journal=Trans R Soc Trop Med Hyg | year=2006 | volume=100 | pages=1087–88 | doi=10.1016/j.trstmh.2006.02.006 ] . "Within the monkey population in Peninsular Malaysia," ""A. hackeri"", "is believed to be the main vector of" 'P. knowlesi' : "although" 'A. hackeri' "is capable of transmitting malaria to humans", [cite journal | author=Wharton RH, Eyles DE. | title="Anopheles hackeri," a vector of "Plasmodium knowlesi" in Malaya | year=1961 | journal=Science | volume=134 | pages=279–80 | doi=10.1126/science.134.3474.279 | pmid=13784726 ] "it is not normally attracted to humans and therefore cannot be an important vector for transmission." [cite journal | author=Reid JA, Weitz B. | year=1961 | title=Anopheline mosquitoes as vectors of animal malaria in Malaya | journal=Ann Trop Med Parasitol | volume=55 | pages=180–6 ]

Diagnosis

"P. knowlesi" infections is diagnosed by examining thick and thin blood films in the same way as other malarias. The appearance of "P. knowlesi" is similar to that of "P. malariae" and is unlikely to be correctly diagnosed except by using molecular detection assays cite journal | journal=Lancet | year=2004 | volume=363 | pages=1017–24 | title=A large focus of naturally acquired "Plasmodium knowlesi" infections in human beings | author=Singh B, Lee KS, Matusop A | doi=10.1016/S0140-6736(04)15836-4 ] in a malaria reference laboratory.

Treatment

"P. knowlesi" infection responds well to treatment with chloroquine and primaquine. A more recent study however found that "P. knowlesi"-infection can prove to be fatal just like "P. falciparum"-malaria, and hence those who reside in or have traveled to the South East Asia should be treated as intensively when found to be suffering from malaria. [cite journal|last-Cox-Singh|first=Janet|coauthors=Timothy M. E. Davis, Kim-Sung Lee, Asmad Matusop, Sunita S. G. Shamsul, Shanmuga Ratnam, Hasan A. Rahman, David J. Conway, and Balbir Singh|title="Plasmodium knowlesi" Malaria in Humans Is Widely Distributed and Potentially Life Threatening|url=http://www.journals.uchicago.edu/doi/full/10.1086/524888?cookieSet=1|journal=Clinical Infectious Diseases|volume=46|pages=165—171|publisher=University of Chicago Press/Infectious Diseases Society of America|date=2008-01-15|doi=10.1086/524888|pmid=18171245|accessdate=2008-07-17]

Plasmodium knowlesi genome data

* [http://www.genedb.org/genedb/pknowlesi/ GeneDB Plasmodium knowlesi]

References