Plasmodium knowlesi: Difference between revisions

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*The approach to diagnosis of P. knowlesi malaria consists of microscopy to guide immediate clinical management, followed by confirmatory testing with PCR.
*The approach to diagnosis of P. knowlesi malaria consists of microscopy to guide immediate clinical management, followed by confirmatory testing with PCR.
*PCR is the gold standard diagnostic tool with high sensitivity and specificity.<ref name="pmid19812279">{{cite journal |vauthors=Imwong M, Tanomsing N, Pukrittayakamee S, Day NP, White NJ, Snounou G |title=Spurious amplification of a Plasmodium vivax small-subunit RNA gene by use of primers currently used to detect P. knowlesi |journal=J. Clin. Microbiol. |volume=47 |issue=12 |pages=4173–5 |date=December 2009 |pmid=19812279 |pmc=2786678 |doi=10.1128/JCM.00811-09 |url=}}</ref>
*PCR is the gold standard diagnostic tool with high sensitivity and specificity.<ref name="pmid19812279">{{cite journal |vauthors=Imwong M, Tanomsing N, Pukrittayakamee S, Day NP, White NJ, Snounou G |title=Spurious amplification of a Plasmodium vivax small-subunit RNA gene by use of primers currently used to detect P. knowlesi |journal=J. Clin. Microbiol. |volume=47 |issue=12 |pages=4173–5 |date=December 2009 |pmid=19812279 |pmc=2786678 |doi=10.1128/JCM.00811-09 |url=}}</ref>
*Microscopy is a sensitive tool For the detection of level of parasitemia and to know the life cycle stages of Plasmodium knowlesi.


==Treatment==
==Treatment==

Revision as of 14:35, 12 November 2018

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Marjan Khan M.B.B.S.[2]

Plasmodium knowlesi
Scientific classification
Kingdom: Protista
Phylum: Apicomplexa
Class: Aconoidasida
Order: Haemosporida
Family: Plasmodiidae
Genus: Plasmodium
Species: P. knowlesi
Binomial name
Plasmodium knowlesi

Overview

Plasmodium knowlesi is a simian parasite that cause malaria; the natural hosts are macaques.[1] Human cases of Plasmodium knowlesi malaria have been reported throughout the Southeast Asia; most cases have been reported from Malaysia, particularly the eastern Malaysian states of Sabah and Sarawak.[2] this malaria is generally acquired in forest or forest-fringe areas; those at risk include farmers, plantation workers, and individuals undertaking other activities in forested areas. Adult population is commonly affected more than children and the mortality increases as the age increases. [3]

Epidemiology

  • Reports of human P. knowlesi infections are confined to Southeast Asia,[4][5] particularly Malaysia,[6] but there are also reports on the Thai-Burmese border.[7] A fifth of the cases of malaria diagnosed in Sarawak, Malaysian Borneo are due to P. knowlesi.[6]
  • P. knowlesi infection is normally considered an infection of long-tailed (Macaca fascicularis) and pig-tailed (M. 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 first case of naturally acquired human infection with P. knowlesi was reported in 1965 in a United States national working in Malaysia.[8]
  • 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[9]. 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,[10] it is not normally attracted to humans and therefore cannot be an important vector for transmission.[11]

Transmission and risk factors for infection

  • Human-mosquito-human transmission has been demonstrated in the laboratory setting but has not yet been proven to occur in the natural environment.[12]
  • Cases of P. knowlesi in humans have been reported to occur in clusters, affecting individuals of all ages.
  • Transmission is predominantly zoonotic but it appears possible that human-mosquito-human transmission may occur (at least to some degree) in endemic areas.[13]
  • Risk factors for acquiring P. knowlesi infection include:[14]
  1. Male gender
  2. Age greater than 15 years
  3. Sleeping outside
  4. Proximity to monkeys in the preceding four weeks
  5. Presence of open eaves or gaps in walls
  6. Presence of long grass around dwelling
  • Protective factors against P. knowlesi infection in one study included:[14]
  1. G6PD deficiency
  2. Residual insecticide spraying of household walls
  3. Presence of sparse forest or rice paddies around the house
  4. Use of bed nets was not protective
  • children Less than 15 years accounted for only 10 % of all P. knowlesi cases in Sabah, Malaysia, between 2010 and 2014.[15]
  • Transfusion-transmitted P. knowlesi malaria has been reported in Malaysia.[16]

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 [6]
  • Reporting of P. knowlesi as the more benign P. malariae has been associated with failure to recognize severe malaria and consequent delayed initiation of parenteral therapy, with fatal outcomes.
  • P. knowlesi malaria should be suspected in the setting of febrile illness after exposure to regions where P. knowlesi malaria is endemic.
  • The approach to diagnosis of P. knowlesi malaria consists of microscopy to guide immediate clinical management, followed by confirmatory testing with PCR.
  • PCR is the gold standard diagnostic tool with high sensitivity and specificity.[17]
  • Microscopy is a sensitive tool For the detection of level of parasitemia and to know the life cycle stages of Plasmodium knowlesi.

Treatment

P. knowlesi infection responds well to treatment with chloroquine and primaquine.[6]

Plasmodium knowlesi genome data

References

  1. ↑ Napier LE, Campbell H (May 1932). "Observations on a Plasmodium Infection Which Causes Hæmoglobinuria in Certain Species of Monkey". Ind Med Gaz. 67 (5): 246–249. PMC 5231784. PMID 29011028. Vancouver style error: initials (help)
  2. ↑ Shearer FM, Huang Z, Weiss DJ, Wiebe A, Gibson HS, Battle KE, Pigott DM, Brady OJ, Putaporntip C, Jongwutiwes S, Lau YL, Manske M, Amato R, Elyazar IR, Vythilingam I, Bhatt S, Gething PW, Singh B, Golding N, Hay SI, Moyes CL (August 2016). "Estimating Geographical Variation in the Risk of Zoonotic Plasmodium knowlesi Infection in Countries Eliminating Malaria". PLoS Negl Trop Dis. 10 (8): e0004915. doi:10.1371/journal.pntd.0004915. PMC 4975412. PMID 27494405.
  3. ↑ Grigg MJ, William T, Barber BE, Rajahram GS, Menon J, Schimann E, Piera K, Wilkes CS, Patel K, Chandna A, Drakeley CJ, Yeo TW, Anstey NM (July 2018). "Age-Related Clinical Spectrum of Plasmodium knowlesi Malaria and Predictors of Severity". Clin. Infect. Dis. 67 (3): 350–359. doi:10.1093/cid/ciy065. PMC 6051457. PMID 29873683.
  4. ↑ Chin W, Contacos PG, Coatney RG, Kimbal HR. (1965). "A naturally acquired quotidian-type malaria in man transferable to monkeys". Science. 149: 865. PMID 14332847.
  5. ↑ Yap FL, Cadigan FC, Coatney GR. (1971). "A presumptive case of naturally occurring Plasmodium knowlesi malaria in man in Malaysia". Trans R Soc Trop Med Hyg. 65 (6): 839&ndash, 40. PMID 5003320.
  6. ↑ 6.0 6.1 6.2 6.3 Singh B, Lee KS, Matusop A, Radhakrishnan A, Shamsul SSG, Cox-Singh J, Thomas A, Conway DJ (2004). "A large focus of naturally acquired Plasmodium knowlesi infections in human beings". Lancet. 363: 1017&ndash, 24. doi:10.1016/S0140-6736(04)15836-4.
  7. ↑ Jongwutiwes S, Putaporntip C, Iwasaki T, Sata T, Kanbara H. (2004). "Naturally acquired Plasmodium knowlesi malaria in human, Thailand". Emerg Infect Dis. 10 (12): 2211&ndash, 3. PMID 15663864.
  8. ↑ CHIN W, CONTACOS PG, COATNEY GR, KIMBALL HR (August 1965). "A NATURALLY ACQUITED QUOTIDIAN-TYPE MALARIA IN MAN TRANSFERABLE TO MONKEYS". Science. 149 (3686): 865. PMID 14332847.
  9. ↑ Vythilingam I, Tan CH, Asmad M, Chan ST, Lee KS, Singh B. (2006). "Natural transmission of Plasmodium knowlesi to humans by Anopheles latens in Sarawak, Malaysia". Trans R Soc Trop Med Hyg. 100: 1087&ndash, 88. doi:10.1016/j.trstmh.2006.02.006.
  10. ↑ Wharton RH, Eyles DE. (1961). "Anopheles hackeri, a vector of Plasmodium knowlesi in Malaya". Science. 134: 279&ndash, 80.
  11. ↑ Reid JA, Weitz B. (1961). "Anopheline mosquitoes as vectors of animal malaria in Malaya". Ann Trop Med Parasitol. 55: 180&ndash, 6.
  12. ↑ Chin W, Contacos PG, Collins WE, Jeter MH, Alpert E (May 1968). "Experimental mosquito-transmission of Plasmodium knowlesi to man and monkey". Am. J. Trop. Med. Hyg. 17 (3): 355–8. PMID 4385130.
  13. ↑ Barber BE, William T, Dhararaj P, Anderios F, Grigg MJ, Yeo TW, Anstey NM (December 2012). "Epidemiology of Plasmodium knowlesi malaria in north-east Sabah, Malaysia: family clusters and wide age distribution". Malar. J. 11: 401. doi:10.1186/1475-2875-11-401. PMC 3528466. PMID 23216947.
  14. ↑ 14.0 14.1 Grigg MJ, Cox J, William T, Jelip J, Fornace KM, Brock PM, von Seidlein L, Barber BE, Anstey NM, Yeo TW, Drakeley CJ (June 2017). "Individual-level factors associated with the risk of acquiring human Plasmodium knowlesi malaria in Malaysia: a case-control study". Lancet Planet Health. 1 (3): e97–e104. doi:10.1016/S2542-5196(17)30031-1. PMC 5531251. PMID 28758162.
  15. ↑ Rajahram GS, Barber BE, William T, Grigg MJ, Menon J, Yeo TW, Anstey NM (January 2016). "Falling Plasmodium knowlesi Malaria Death Rate among Adults despite Rising Incidence, Sabah, Malaysia, 2010-2014". Emerging Infect. Dis. 22 (1): 41–8. doi:10.3201/eid2201.151305. PMC 4696710. PMID 26690736.
  16. ↑ Bird EM, Parameswaran U, William T, Khoo TM, Grigg MJ, Aziz A, Marfurt J, Yeo TW, Auburn S, Anstey NM, Barber BE (July 2016). "Transfusion-transmitted severe Plasmodium knowlesi malaria in a splenectomized patient with beta-thalassaemia major in Sabah, Malaysia: a case report". Malar. J. 15 (1): 357. doi:10.1186/s12936-016-1398-z. PMC 4942937. PMID 27405869.
  17. ↑ Imwong M, Tanomsing N, Pukrittayakamee S, Day NP, White NJ, Snounou G (December 2009). "Spurious amplification of a Plasmodium vivax small-subunit RNA gene by use of primers currently used to detect P. knowlesi". J. Clin. Microbiol. 47 (12): 4173–5. doi:10.1128/JCM.00811-09. PMC 2786678. PMID 19812279.

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