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alaria is caused by protozoan
parasites called Plasmodia, belonging to the parasitic phylum
Apicomplexa. More than 200 species of the genus Plasmodium
(=plasma + eidos, form) have been identified that are parasitic to
reptiles, birds, and mammals.[1] Four Plasmodium species have
been well
known to cause human malaria, namely, P. falciparum, P.
vivax, P. ovale, and P. malariae. A fifth one, P. knowlesi, has
been recently documented to cause human infections in many countries
of
Southeast Asia.[2] Very rare cases of malaria have been reported due
to other species such as Plasmodium brasilianum, Plasmodium
cynomolgi, Plasmodium cynomolgi bastianellii, Plasmodium inui,
Plasmodium rhodiani, Plasmodium schwetzi, Plasmodium semiovale,
Plasmodium simium and Plasmodium eylesi. All malaria parasites infecting humans probably
jumped from the great apes (in case of P. knowlesi, macaques)
to man.[See]
Phylum: Protozoa Subphylum:
Apicomplexa
Class: Sporozoa Subclass:
Coccidia
Order: Coccidiida Suborder:
Haemosporina
Family:
Plasmodiidae
Genus: Plasmodia
Subgenera:
Plasmodium, Laverania
Species: (affecting
man)
Quartan group: P.
(Plasmodium) malariae, P. (P.) brasilianum
Benign tertian group: P.
(P.) vivax, P. (P.) cynomolgi, P. (P.) cynomolgi bastianellii
Malignant tertian group: P.
(Laverania) falciparum
Ovale group: P. (P.)
ovale, P. (P.) simium
Knowlesi group:
P. (P.)
knowlesi
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See
Phylogenetic Trees of Plasmodia [Click to Enlarge]
|
Tree of Life Web Project [above] and
Krief S et al.
On the Diversity of Malaria Parasites in African Apes and the
Origin of P. falciparum from Bonobos. PLoS Pathog
2010;6(2): e1000765.[Full
Text][Right] |
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Subtypes of P. vivax: Plasmodium vivax is divided into
two subtypes, a dominant form, VK210 and a variant form, VK247. This
division is dependent on the amino acid composition of the
circumsporozoite (CS) protein. A strain of P. vivax containing a
variant repeat in its CS protein was first isolated in Thailand.[3,4].
The CS repeat of this variant strain (Thai VK247) differs at 6/9 amino
acids within the repeat sequence found in all previously described P.
vivax CS protein. Following this discovery, several studies have
been conducted to evaluate the global distribution of variant VK247; it
was detected in indigenous populations of China [5], Brazil [6], Mexico
[7,8], Peru [8,9], and Papua New Guinea [8]. It is known that the drug
susceptibility of the VK247 subtype of P. vivax is slightly
different than VK210 [10], as well as that Anopheles albimanus
and Anopheles pseudopunctipennis differ in their susceptibilities
to P. vivax circumsporozoite phenotypes. Anopheles albimanus
is more susceptible to the VK210 subtype, whereas An.
pseudopunctipennis is more susceptible to the VK247 subtype.[11]
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Two
species of P. ovale: P. ovale has been found to
exist in two forms, classic and variant, with the latter accounting for
the higher parasite density among humans. A new study has now proposed
that ovale malaria in humans is caused by two closely related but
distinct species of malaria parasite, Plasmodium ovale curtisi
(classic type) and Plasmodium ovale wallikeri (variant type),
named so in honor of malaria researchers Christopher F. Curtis
(1939-2008) and David Walliker (1940-2007). These two nonrecombining,
genetically distinct species coexist, being sympatric in Africa and
Asia. Splitting of the 2 lineages is estimated to have occurred between
1.0 and 3.5 million years ago in hominid hosts.[12-16]
Christopher F. Curtis (1939-2008)[More at
The Lancet] |
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Molecular characteristics of malarial parasites have also been studied in
India.[17]
Distribution of Plasmodia: Nearly 85% of cases in Africa are caused
by P. falciparum, the remaining cases being caused by the other
three strains. P. vivax is now the most geographically widespread
of the human malarias, occurring in much of Asia, Central and South
America, the Middle East, where 70–90% of the malaria burden is of this
species and the rest due to P. falciparum.[1,18] P. malariae
causes sporadic infections in Africa, parts of India, western
Pacific and South America, whereas P. ovale is restricted to
tropical Africa, New Guinea, and the Philippines.[18] P. knowlesi has
been reported from South East Asian countries such as Malaysia, Thailand, Viet Nam,
Myanmar and Phillippines.[19-23]
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Analyses of the mtDNA data have revealed that P. knowlesi is
derived from an ancestral parasite population that existed prior
to human settlement in Southeast Asia, and underwent significant
population expansion approximately 30,000–40,000 years ago. The
results indicate that human infections with P. knowlesi are not
newly emergent in Southeast Asia and that knowlesi malaria is
primarily a zoonosis with wild macaques as the reservoir hosts.
Ongoing ecological changes resulting from deforestation, with an
associated increase in the human population, could enable this
pathogenic species of Plasmodium to switch to humans as the
preferred host.[24] |
 |
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Comparison of malaria parasites [21,25-32]
|
| |
P. falciparum |
P. vivax |
P. ovale |
P. malariae |
P. knowlesi |
|
Global Distribution |
80-90% of cases in Africa, 40-50% of
cases in western pacific and SE Asia, 4-30% in S Asia, S America
and rest of tropics |
70-90% of cases in most of Asia and S
America, 50-60% of cases in SE Asia and western pacific, 1-10% in Africa |
8% of cases in parts of Africa, stray
cases in Asia |
2-3% in Africa, sporadic in Asia and
S America |
Reported from SE Asia;
70% of cases in some of those areas |
|
Occurrence in India |
30–90% of cases in Orissa, the
NE states, Chattisgarh, Jharkhand, Madhya Pradesh, Bihar, and Andamans;
<10% of cases in other areas |
Nearly 50% of total malaria burden;
predominant species in most parts other than P. falciparum dominant
areas. |
Stray cases reported from
Delhi, Gujarat Kolkata, Orissa,
and Assam |
3-16% reported from some tribal areas,
particularly Orissa; sporadic elsewhere; incidence may be higher |
Not reported |
Tissue schizogony |
5-6 days |
8 days |
9 days |
13 days |
8-9 days |
Erythrocytic phase |
48 hours |
48 hours |
49-50 hours |
72 hours |
24 hours |
Red cells affected |
All |
Reticulocytes |
Reticulocytes |
Mature RBC's |
? |
|
Merozoites per tissue schizont |
40000 |
Over 10000 |
15000 |
2000 |
? |
Merozoites per red cell schizont |
8 - 32 |
12 - 24 |
4 - 16 |
6 - 12 |
10-16 |
Relapse from persistent liver forms |
No |
Yes |
Yes |
No, but blood forms can persist up to 30 years |
No |
|
Fever pattern |
Tertian, sub tertian |
Tertian |
Tertian |
Quartan |
Quotidian |
|
Severe malaria |
Up to 24% |
Up to 22% |
Very rare |
Very rare |
6-10% |
Drug resistance |
Yes |
Yes |
No |
No |
No |
|
See Comparison of Four Human Plasmodium species at CDC |
|
Ring Forms of
Malaria Parasites on Thin Blood Smear
(Courtesy:
CDC DPDx Image
Library) |
 |
 |
 |
|
Ring Forms of
P. falciparum |
Ring Forms of
P.
vivax |
Ring Forms of
P.
ovale |
 |
 |
|
|
Ring Forms of
P.
malariae |
Ring Forms of
P.
knowlesi |
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Further Reading:
- Rich SM, Ayala FJ.
Evolutionary Origins of Human Malaria Parasites. In Krishna R.
Dronamraju, Paolo Arese (Ed). Emerging Infectious Diseases of the
21st Century: Malaria - Genetic and Evolutionary Aspects. Springer
US 2006. pp.125-146.
- Daneshvar C et
al. Clinical and Laboratory Features of Human Plasmodium
knowlesi Infection. Clinical Infectious Diseases
2009;49:852–860.
- Tong-Soo Kim et
al. Prevalence of Plasmodium vivax VK210 and VK247 subtype
in Myanmar. Malaria Journal 2010;9:195.
doi:10.1186/1475-2875-9-195. Available at
http://www.malariajournal.com/content/9/1/195
- Rosenberg R,
Wirtz RA, Lanar DE, Sattabongkot J, Hall T, Waters AP, Prasittisuk
C. Circumsporozoite protein heterogeneity in the human malaria
parasite Plasmodium vivax. Science 1989;245:973-976.
- Han GD, Zhang XJ,
Zhang HH, Chen XX, Huang BC. Use of PCR/DNA probes to identify
circumsporozoite genotype of Plasmodium vivax in China.
Southeast Asian J Trop Med Pub Health 1999;30:20-23.
- Branquinho MS,
Lagos CB, Rocha RM, Natal D, Barata JM, Cochrane AH, Nardin E,
Nussenzweig RS, Kloetzel JK. Anophelines in the state of Acre,
Brazil, infected with Plasmodium falciparum, P. vivax, the
variant P. vivax VK247 and P. malariae. Trans R
Soc Trop Med Hyg 1993;87:391-394.
- Kain KC, Brown
AE, Webster HK, Wirtz RA, Keystone JS, Rodriguez MH, Kinahan J,
Rowland M, Lanar DE. Circumsporozoite genotyping of global
isolates of Plasmodium vivax from dried blood specimens.
J Clin Microbiol 1992;30:1863-1866.
- Kain KC, Wirtz
RA, Fernandez I, Franke ED, Rodriguez MH, Lanar DE. Serologic and
genetic characterization of Plasmodium vivax from whole
blood-impregnated filter paper discs. Am J Trop Med Hyg
1992;46:473-479.
- Need JT, Wirtz
RA, Franke ED, Fernandez R, Carbajal F, Falcon R, San Roman E.
Plasmodium vivax VK247 and VK210 circumsporozoite proteins in
Anopheles mosquitoes from Andoas, Peru. J Med Entomol
1993;30:597-600.
- Kain KC, Brown
AE, Lanar DE, Ballou WR, Webster HK. Response of Plasmodium
vivax variants to chloroquine as determinated by microscopy
and quantitative polymerase chain reaction. Am J Trop Med Hyg
1993;49:478-484.
- González-Cerón
L, Rodriguez MH, Nettel JA, Villarreal C, Kain KC, Hernández JE.
Differential susceptibility of Anopheles albimanus and
Anopheles pseudopunctipennis to infections with coindigenous
Plasmodium vivax variants VK210 and VK247 in southern
Mexico. Infect Immun 1999;67:410-412.
- Sutherland CJ et al. Two nonrecombining sympatric forms of the
human malaria parasite Plasmodium ovale occur globally. J
Infect Dis. 15 May 2010;201(10):1544-1550.[Full
Text]
- Xin-zhuan Su. Human Malaria Parasites: Are We Ready for a New
Species? J Infect Dis. 2010;201(10):1453-1454. [Extract]
- Akpogheneta O. Researchers Identify New Malaria Species.
The Faster Times. Available at
http://thefastertimes.com/globalpandemics/2010/04/22/researchers-identify-a-new-malaria-species/
- Oguike MC et al. Plasmodium ovale curtisi and
Plasmodium ovale wallikeri circulate simultaneously in African
communities.
Int J Parasitol. 23 Feb 2011 [Pub
Med Abstract]
- David Tordrup et al. Variant Plasmodium ovale isolated
from a patient infected in Ghana. Malaria Journal 2011;10:15.
doi:10.1186/1475-2875-10-15. Full text at
http://www.malariajournal.com/content/10/1/15
- Characterization
of Human Malaria Parasites. Available at
http://www.mrcindia.org/MRC_profile/profile2/Characterization of
human malaria Parasites.pdf
- Carter R, Mendis
KN. Evolutionary and Historical Aspects of the Burden of Malaria.
Clinical Microbiology Reviews. October 2002;15(4):564-594.
Full text at
http://cmr.asm.org/cgi/content/full/15/4/564
-
Cyrus Daneshvar,
Timothy M. E. Davis, Janet Cox-Singh, Mohammad Zakri Rafa’ee, Siti
Khatijah Zakaria, Paul C. S. Divis, Balbir Singh. Clinical and
Laboratory Features of Human Plasmodium knowlesi Infection.
Clinical Infectious Diseases 2009;49:852–860
-
Chaturong Putaporntip,
Thongchai Hongsrimuang, Sunee Seethamchai et al. Differential
Prevalence of Plasmodium Infections and Cryptic Plasmodium
knowlesi Malaria in Humans in Thailand. The Journal of
Infectious Diseases 2009;199:1143–1150
-
Balbir Singh, Lee Kim
Sung, Anand Radhakrishnan et al. A large focus of naturally acquired
Plasmodium knowlesi infections in human beings. The Lancet
2004;363(9414):1017-1024
-
Janet Cox-Singh,
Balbir Singh. Knowlesi malaria: newly emergent and of public health
importance? Trends in Parasitology. 2008;24(9):406-410
-
Peter Van den Eede,
Hong Nguyen Van, Chantal Van Overmeir et al. Human Plasmodium
knowlesi infections in young children in central Vietnam.
Malaria Journal 2009;8:249. Full Text at
http://www.malariajournal.com/content/8/1/249
-
Lee K-S, Divis PCS, Zakaria SK, Matusop A, Julin RA, et al.
Plasmodium knowlesi: Reservoir Hosts and Tracking the Emergence
in Humans and Macaques. PLoS Pathog 2011;7(4):e1002015.
doi:10.1371/journal.ppat.1002015. Available at
http://www.plospathogens.org/article/info%3Adoi%2F10.1371%2Fjournal.ppat.1002015
-
Dhangadamajhi G, Kar SK, Ranjit MR. High prevalence and gender
bias in distribution
of Plasmodium malariae infection in central east-coast India.
Tropical Biomedicine
2009;26(3): 326–333. Available at
http://www.msptm.org/files/326_-_333_Ranjit_MR.pdf
- Rajagopalan PK,
Pani SP, Das PK, Jambulingam P. Malaria in Koraput district of
Orissa. Indian J Pediatr. 1989 May-Jun;56(3):355-64.
- Ashwani
Kumar, Neena Valecha, Tanu Jain, Aditya P. Dash. Burden of Malaria
in India: Retrospective and Prospective View. Am. J. Trop. Med.
Hyg. 2007;77(6_Suppl):69-78. Full Text at
http://www.ajtmh.org/cgi/reprint/77/6_Suppl/69
- Malaria
situation. National Vector Borne Disease control Programme.
Available at
http://nvbdcp.gov.in/Doc/Malaria%20Situation_Sep.pdf
- Matteelli
A, Castelli F, Caligaris S. Life cycle of malaria parasites. In
Carosi G, Castelli F. (Ed) Handbook of Malaria Infection in the
Tropics. Associazione Italiana ‘Amici di R Follereau’
Organizzazione per la Cooperazione Sanitaria Internazionale.
Bologna. 1997. pp. 17-23. Available at
http://www.aifo.it/english/resources/online/books/other/malaria/2-Lifecycle%20of%20malarial%20parasite.pdf
- Rogerson
SJ, Carter R. Severe Vivax Malaria: Newly Recognised or
Rediscovered? PLoS Med. 2008;5(6):e136. Full Text at
http://www.plosmedicine.org/article/info:doi/10.1371/journal.pmed.0050136
- Genton B,
D'Acremont V, Rare L, Baea K, Reeder JC et al. Plasmodium vivax
and Mixed Infections Are Associated with Severe Malaria in
Children: A Prospective Cohort Study from Papua New Guinea.
PLoS Med 2008;5(6):e127. Full Text at
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- Tjitra E,
Anstey NM, Sugiarto P, Warikar N, Kenangalem E, et al. Multidrug-Resistant
Plasmodium vivax Associated with Severe and Fatal Malaria: A
Prospective Study in Papua, Indonesia. PLoS Med
2008;5(6):e128. Full Text at
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