This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Collins, W. E. Articles by Jeffery, G. M. Search for Related Content PubMed PubMed Citation Articles by Collins, W. E. Articles by Jeffery, G. M.

 Previous Article  |  Next Article 

Clinical Microbiology Reviews, July 2005, p. 570-581, Vol. 18, No. 3
0893-8512/05/$08.00+0     doi:10.1128/CMR.18.3.570-581.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.

Plasmodium ovale: Parasite and Disease

Centers for Disease Control and Prevention, National Center for Infectious Diseases, Division of Parasitic Diseases, Malaria Branch, Chamblee, Georgia 30341,¹ U.S. Public Health Service, Atlanta, Georgia²

Humans are infected by four recognized species of malaria parasites. The last of these to be recognized and described is Plasmodium ovale. Like the other malaria parasites of primates, this parasite is only transmitted via the bites of infected Anopheles mosquitoes. The prepatent period in the human ranges from 12 to 20 days. Some forms in the liver have delayed development, and relapse may occur after periods of up to 4 years after infection. The developmental cycle in the blood lasts approximately 49 h. An examination of records from induced infections indicated that there were an average of 10.3 fever episodes of 101°F and 4.5 fever episodes of 104°F. Mean maximum parasite levels were 6,944/µl for sporozoite-induced infections and 7,310/µl for trophozoite-induced infections. Exoerythrocytic stages have been demonstrated in the liver of humans, chimpanzees, and Saimiri monkeys following injection of sporozoites. Many different Anopheles species have been shown to be susceptible to infection with P. ovale, including A. gambiae, A. atroparvus, A. dirus, A. freeborni, A. albimanus, A. quadrimaculatus, A. stephensi, A. maculatus, A. subpictus, and A. farauti. An enzyme-linked immunosorbent assay has been developed to detect mosquitoes infected with P. ovale using a monoclonal antibody directed against the circumsporozoite protein. Plasmodium ovale is primarily distributed throughout sub-Saharan Africa. It has also been reported from numerous islands in the western Pacific. In more recent years, there have been reports of its distribution on the Asian mainland. Whether or not it will become a major public health problem there remains to be seen. The diagnosis of P. ovale is based primarily on the characteristics of the blood stages and its differentiation from P. vivax. The sometimes elliptical shape of the infected erythrocyte is often diagnostic when combined with other, subtler differences in morphology. The advent of molecular techniques, primarily PCR, has made diagnostic confirmation possible. The development of techniques for the long-term frozen preservation of malaria parasites has allowed the development diagnostic reference standards for P. ovale. Infections in chimpanzees are used to provide reference and diagnostic material for serologic and molecular studies because this parasite has not been shown to develop in other nonhuman primates, nor has it adapted to in vitro culture. There is no evidence to suggest that P. ovale is closely related phylogenetically to any other of the primate malaria parasites that have been examined.

This article has been cited by other articles:

• Coldren, R. L., Jongsakul, K., Vayakornvichit, S., Noedl, H., Fukudas, M. M. (2007). Apparent Relapse of Imported Plasmodium ovale Malaria in a Pregnant Woman. Am J Trop Med Hyg 77: 992-994 [Abstract] [Full Text]  
• Calderaro, A., Piccolo, G., Perandin, F., Gorrini, C., Peruzzi, S., Zuelli, C., Ricci, L., Manca, N., Dettori, G., Chezzi, C., Snounou, G. (2007). Genetic Polymorphisms Influence Plasmodium ovale PCR Detection Accuracy. J. Clin. Microbiol. 45: 1624-1627 [Abstract] [Full Text]  
• Conway, D. J. (2007). Molecular Epidemiology of Malaria. Clin. Microbiol. Rev. 20: 188-204 [Abstract] [Full Text]