Trends in Parasitology
Vivax series:The co-existence of Plasmodium: sidelights from falciparum and vivax malaria in Thailand
Section snippets
Out of sight…
Mixed species infections have been a relatively neglected field during the prolific early investigations on malaria. This was due, in part, to the debate on the existence of different Plasmodium species of humans. In the 1890s, Italian malariologists split these parasites into three species, whereas Alphonse Laveran championed the idea that they all belonged to a single species – the ‘unicity’ theory – with the parasites merely changing morphologically. The debate was finally laid to rest in
An emerging interest
Over the past decade, interest in the question of mixed-species Plasmodium infections has revived. This has been sparked by the introduction of sensitive molecular tools of detection, and sustained by the realization by a growing number of researchers that Plasmodium species other than P. falciparum are worthy of study. The first conference entirely devoted to P. vivax (‘Vivax Malaria Research: 2002 and Beyond’, convened by the Multilateral Initiative on Malaria in February 2002 in Bangkok,
A natural experiment
Clinical and epidemiological observations in Thailand, more than in any other endemic setting, have brought malaria mixed infections to the attention of malariologists. Thailand is particularly well suited to provide insights on interactions between Plasmodium species for several reasons. Thailand boasts excellent country-wide epidemiological surveillance and hosts several continuously monitored sites. Data are available for numerous patients recruited for drug efficacy studies who have been
Beneficial associations
The Shoklo camp on the Thai–Myanmar border in western Thailand, where Karen populations displaced by armed conflict took refuge since 1984, has provided an excellent setting for detailed long-term epidemiological and clinical observations of malaria. However, malaria epidemiology at this site and at that time is unlikely to be representative of the rest of Thailand, and patient recruitment in the early 1990s was coincident with the peak crisis of mefloquine resistance and the first efforts to
Too many mixed infections
The levels of mixed infections recorded in Shoklo contrast sharply with those recorded for the rest of the country. Indeed, P. falciparum and P. vivax were found together only in 0.3–0.7% of the total positive blood smears recorded in Thailand [51]. If this were the true prevalence of mixed species infections, then any interactions between the species would have minimal impact on public health. However, there are compelling indications that the higher levels of mixed infection recorded in
Mixed perspectives
Two immediate conclusions can be drawn from the observations made in Thailand and elsewhere: (i) mixed-species malaria infections are common; and (ii) they are likely to have an impact on the morbidity and epidemiology of malaria. The growing trend to include non-P. falciparum infections in the analysis of epidemiological and clinical data is providing glimpses of interesting associations with mixed infections in other areas where the different species are prevalent such as Papua New Guinea [73]
References (77)
Observations on the natural history of malaria in the semi-resistant West African
Trans. R. Soc. Trop. Med. Hyg.
(1958)- et al.
Immunological studies on simian malaria parasites. IV. Heterologous superinfection of monkeys with chronic Plasmodium knowlesi infections
Trans. R. Soc. Trop. Med. Hyg.
(1969) - et al.
The course of simultaneously inoculated, concomitant infections with Plasmodium vinckei and Plasmodium berghei in white mice
Trans. R. Soc. Trop. Med. Hyg.
(1970) Identification of the four human malaria parasite species in field samples by the polymerase chain reaction and detection of a high prevalence of mixed infections
Mol. Biochem. Parasitol.
(1993)High sensitivity of detection of human malaria parasites by the use of nested polymerase chain reaction
Mol. Biochem. Parasitol.
(1993)The importance of sensitive detection of malaria parasites in the human and insect hosts in epidemiological studies, as shown by the analysis of field samples from Guinea Bissau
Trans. R. Soc. Trop. Med. Hyg.
(1993)Mixed infections with Plasmodium falciparum and P. malariae and fever in malaria
Lancet
(1994)Plasmodium vivax and Plasmodium falciparum: biological interactions and the possibility of cross-species immunity
Parasitol. Today
(1997)- et al.
Cross-species regulation of malaria parasitaemia in the human host
Curr. Opin. Microbiol.
(2002) - et al.
Cross-species regulation of Plasmodium parasitemia in semi-immune children from Papua New Guinea
Trends Parasitol.
(2003)
Mixed species malaria infections in humans
Trends Parasitol.
The blood-stage dynamics of mixed Plasmodium malariae–Plasmodium falciparum infections
J. Theor. Biol.
Sensitivity of Plasmodium vivax to chloroquine in Sa Kaeo Province, Thailand
Acta Trop.
The epidemiology of malaria in a Karen population on the western border of Thailand
Trans. R. Soc. Trop. Med. Hyg.
The epidemiology of severe malaria in an area of low transmission in Thailand
Trans. R. Soc. Trop. Med. Hyg.
Artesunate/mefloquine treatment of multi-drug resistant falciparum malaria
Trans. R. Soc. Trop. Med. Hyg.
Genetic analysis of Plasmodium falciparum infections on the north-western border of Thailand
Trans. R. Soc. Trop. Med. Hyg.
High rate of Plasmodium vivax relapse following treatment of falciparum malaria in Thailand
Lancet
Demonstration by the polymerase chain reaction of mixed Plasmodium falciparum and P. vivax infections undetected by conventional microscopy
Trans. R. Soc. Trop. Med. Hyg.
Cryptic Plasmodium falciparum parasites in clinical P. vivax blood samples from Thailand
Trans. R. Soc. Trop. Med. Hyg.
The assessment of antimalarial drug efficacy
Trends Parasitol.
Impact of chloroquine resistance on malaria mortality
C.R. Acad. Sci. III
The past, present and future of childhood malaria mortality in Africa
Trends Parasitol.
Simian malarias in man: facts, implications, and predictions
Am. J. Trop. Med. Hyg.
Experimentelle reproduktion der malaria
Arch. Schif. U. Trop. Hyg.
Immunisierung gegen malaria
Bft. Z. Arch. Schif. U. Trop. Hyg.
Simultaneous inoculation with Plasmodium vivax and Plasmodium falciparum
Am. J. Trop. Med.
Vernal vivax activity in persons simultaneously inoculated with Plasmodium vivax and Plasmodium falciparum
Am. J. Trop. Med.
Antagonism between species of malaria parasites in induced mixed infections (Preliminary note)
Pub. Health Rep.
Consecutive inoculations with Plasmodium vivax and Plasmodium falciparum
Am. J. Trop. Med.
Observations on the course of naturally acquired malaria in Puerto Rico
Puerto Rico J. Pub. Health Trop. Med.
Studi di epidemiologia malarica in Sardegna
Riv. Malariol.
Observations on the course of malaria in children in an endemic region
Am. J. Trop. Med.
Malaria in the partially immune adult Nigerian
J. Trop. Med. Hyg.
A longitudinal survey of natural malaria infection in a group of West African adults. Part I
West Afr. Med. J.
A longitudinal survey of natural malaria infection in a group of West African adults. Part II
West Afr. Med. J.
A retrospective examination of sporozoite- and trophozoite-induced infections with Plasmodium falciparum in patients previously infected with heterologous species of Plasmodium: effect on development of parasitologic and clinical immunity
Am. J. Trop. Med. Hyg.
Plasmodium malariae infection boosts Plasmodium falciparum gametocyte production
Am. J. Trop. Med. Hyg.
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