| Malaria Genetics and Epidemiology |
| Background Element |
______________________________________________________________________________________________________
The following photographs of rodent malaria parasites were all taken in Edinburgh in 2005. All blood stage parasites are stained with Giemsa's
Solution. Please feel free to use these photographs, but please acknowledge the source.
Plasmodium berghei
P. berghei parasites in mouse blood ----------------------------------------------------------------------->
Four ring-stage trophozoites in one reticulocyte ---------------------------------------------------------->
P. berghei parasites in mouse blood displaying the
asynchronicity of development characteristic of this species ---------------------->
Plasmodium chabaudi
P. chabaudi Day 5 post-inoculation ----------------------------------------------------------------------->
Multiple infection of an erythrocyte ---------------------------------------------------------------------->
Gametocyte ---------------------------------------------------------------------------->
P. chabaudi Day 7 post-inoculation - high parasitaemia ------------------------------------------------->
Plasmodium vinckei
P. vinckei Day 9 post-inoculation ---------------------------------------------------->
Trophozoite ------------------------------------------------------------------------------------------------->
Gametocyte ------------------------------------------------------------------------------------------------->
Gametocyte -------------------------------------------------------------------------------------------------->
Plasmodium yoelii
P. yoelii (clone 17x) day 9 post-innoculation
(note reticulocyte invasion preference) ------------------------------------------------------------------->
Schizont ----------------------------------------------------------------------------------------------------->
Yoelii (YM) day 5 post-inoculation
(this strain invades both reticulocytes and normocytes and is extremely virulent) -------------------->
______________________________________________________________________________________________________
The following photographs show rodent malaria parasites in the mosquito Anopheles stephensi. All parasites are P. yoelii unless otherwise indicated
Mosquito Stage
Mosquito mid-gut infected with oocysts of P. yoelii.
The gut is flattened under a coverslip at x10 magnification.
The oocysts appear as round objects most visible at the bottom left of the gut ----------------------->
Oocyst of P. chabaudi, day 6 Post-infective bloodmeal
Note haemozoin at bottom left ----------------------------------------------------------------------------->
P. yoelii oocyst, day 8 post-infective bloodmeal --------------------------------------------------------->
Various P. yoelii oocyst, day 8 post-infective bloodmeal ------------------------------------->
P. yoelii sporozoites, liberated from a day 8 oocyst by gentle pressure under a coverslip ------------>
The following photographs of rodent malaria parasites were all taken in Edinburgh in 2005. All blood stage parasites are stained with Giemsa's
Solution. Please feel free to use these photographs, but please acknowledge the source.
Plasmodium berghei
P. berghei parasites in mouse blood ----------------------------------------------------------------------->
Four ring-stage trophozoites in one reticulocyte ---------------------------------------------------------->
P. berghei parasites in mouse blood displaying the
asynchronicity of development characteristic of this species ---------------------->
Plasmodium chabaudi
P. chabaudi Day 5 post-inoculation ----------------------------------------------------------------------->
Multiple infection of an erythrocyte ---------------------------------------------------------------------->
Gametocyte ---------------------------------------------------------------------------->
P. chabaudi Day 7 post-inoculation - high parasitaemia ------------------------------------------------->
Plasmodium vinckei
P. vinckei Day 9 post-inoculation ---------------------------------------------------->
Trophozoite ------------------------------------------------------------------------------------------------->
Gametocyte ------------------------------------------------------------------------------------------------->
Gametocyte -------------------------------------------------------------------------------------------------->
Plasmodium yoelii
P. yoelii (clone 17x) day 9 post-innoculation
(note reticulocyte invasion preference) ------------------------------------------------------------------->
Schizont ----------------------------------------------------------------------------------------------------->
Yoelii (YM) day 5 post-inoculation
(this strain invades both reticulocytes and normocytes and is extremely virulent) -------------------->
______________________________________________________________________________________________________
The following photographs show rodent malaria parasites in the mosquito Anopheles stephensi. All parasites are P. yoelii unless otherwise indicated
Mosquito Stage
Mosquito mid-gut infected with oocysts of P. yoelii.
The gut is flattened under a coverslip at x10 magnification.
The oocysts appear as round objects most visible at the bottom left of the gut ----------------------->
Oocyst of P. chabaudi, day 6 Post-infective bloodmeal
Note haemozoin at bottom left ----------------------------------------------------------------------------->
P. yoelii oocyst, day 8 post-infective bloodmeal --------------------------------------------------------->
Various P. yoelii oocyst, day 8 post-infective bloodmeal ------------------------------------->
P. yoelii sporozoites, liberated from a day 8 oocyst by gentle pressure under a coverslip ------------>
Introduction
There are many reasons for using rodent malaria parasites as models for human malaria. The most obvious of
these is the ease with which the whole life cycle (including the sexual stages in mosquitoes) can be achieved in
the laboratory. This is a crucial factor in studying malaria parasites, and one which is very difficult to achieve with
the human parasites with current methods and technology. Apart from the similarities in basic biology between
the rodent and human malaria parasites, they share conserved genetics and genome organization, conserved
housekeeping genes and biochemical processes, and there is considerable evidence for conservation of the
molecular basis of drug-sensitivity and resistance
There are many reasons for using rodent malaria parasites as models for human malaria. The most obvious of
these is the ease with which the whole life cycle (including the sexual stages in mosquitoes) can be achieved in
the laboratory. This is a crucial factor in studying malaria parasites, and one which is very difficult to achieve with
the human parasites with current methods and technology. Apart from the similarities in basic biology between
the rodent and human malaria parasites, they share conserved genetics and genome organization, conserved
housekeeping genes and biochemical processes, and there is considerable evidence for conservation of the
molecular basis of drug-sensitivity and resistance
The origins of the rodent malaria parasites (From Carlton,J.M.R., Hayton,M., Cravo,P.V.L., Walliker,D., 2001. Of mice and malaria mutants: unravelling
the genetics of drug resistance using rodent malaria models. Trends in Parasitology 17, 236-242)
the genetics of drug resistance using rodent malaria models. Trends in Parasitology 17, 236-242)
A map of the locations from which the various rodent parasites were isolated is shown above. The first of the
rodent parasites to be discovered was P. berghei, which was found in the blood of a thicket rat, Grammomys
surdaster, by Vinckei and Lips in 1948. The discovery of P. vinckei followed in 1952, P. chabaudi in 1965, and P.
yoelii was added to the taxonomy in 1974.
rodent parasites to be discovered was P. berghei, which was found in the blood of a thicket rat, Grammomys
surdaster, by Vinckei and Lips in 1948. The discovery of P. vinckei followed in 1952, P. chabaudi in 1965, and P.
yoelii was added to the taxonomy in 1974.
Rodent Malaria Parasites