Plasmodium falciparum

0verview Malaria Plasmodium falciparum biology toxins Vaccines Mosquitoes

What is Plasmodium falciparum? Protozoa Malaria Malaria is not caused by a bacteria or a virus. It is caused by Plasmodium falciparium, a protozoa. A protozoa is a single celled eukaryotic organism. It was once believed that malaria was spread by foul smelling swamp gasses hence the name malaria which literally means bad air. It is now known that malaria is spread through an arthropod vector, namely the female Anopheles mosquito . Malaria was once more widespread, but has been eradicated in many temperate areas. Malaria is still endemic in the tropics and subtropics and is especially prevalent in Africa. This picture is a map showing the areas where malaria is still endemic. Information on this page from World Health Organization’s Malaria page http://mosquito.who.int/cmc_upload/0/000/015/372/RBMInfosheet_1.htm http://www.traveldoctor.info/diseases/1.html

Impact 300 million acute illness 100 million deaths A child in Africa dies every 30 seconds Malaria is the third leading cause of death due to infectious disease. It causes approximately 300 million acute illnesses per year. It is unknown how many actual cases of malaria there are per year because symptoms of a mild case of malaria are flu like and hard to distinguish from other illnesses. Malaria is responsible for 100 million deaths each year mostly in children under 5. A child in Africa dies every 30 seconds of malaria. After the age of 5 survivors in endemic areas have often developed immunity and do not contract malaria at the same rate or with the same severity that it was previously known. Information on this page from World Health Organization’s Malaria page http://mosquito.who.int/cmc_upload/0/000/015/372/RBMInfosheet_1.htm http://mosquito.who.int/cmc_upload/0/000/015/372/RBMInfosheet_1.htm

Most vulnerable population Pregnant women are also at increased risk of infection and death from malaria. Pregnancy decreases a woman’s natural immunity to malaria. She is more likely to develop severe malaria during pregnancy and it is a leading cause of spontaneous abortion, stillbirth and low birth weigh in malaria endemic areas. 0ver 200,000 newborn deaths are attributed to malaria. It is estimated that maternal malaria causes the deaths of 10,000 women annually. The photo is of someone holding up the tiny foot of a low birth weight infant whose mother had malaria. Plasmodium falciparum often targets the placenta because it is rich in blood and nutrients. The parasite lyses blood cells and leaches nutrients, causing low birth weight in infants. Information on this slide from the cdc webpage about malaria and pregnancy: http://www.cdc.gov/malaria/pregnancy.htm http://www.lakareutangranser.se/default.asp?mall=1&ArtikelID=165&UrvKat=43&Kategori=

Symptoms of infection Characteristic fever 2-3 day cycle cold stage hot stage sweating stage Anemia Renal failure Seizures coma Symptoms of malaria include a characteristic fever which has a 2-3 day cycle. The first stage in malarial disease is the cold stage, where the patient has no fever. During this stage the parasite is inside the red blood cells. The second stage in malarial fever is the hot stage, when the parasite lyses the blood cells and is free in the blood stream searching out new red blood cells to infect. The final stage of malarial fever is the sweating stage, the parasites have infected new red blood cells and the fever rapidly drops causing the patient to sweat. Anemia is a common complication of malaria and is a direct result of the parasite destroying red blood cells. More severe symptoms of malaria might include, but are not limited to: seizures, renal failure, coma and death. These severe symptoms are caused by rosetting which is described later in more detail. Information on this page from World Health Organization’s Malaria page http://mosquito.who.int/cmc_upload/0/000/015/372/RBMInfosheet_1.htm

Diagnosis Symptoms Microscopy PCR ELISA Diagnosis of malaria is difficult because general symptoms of non-severe cases are manifested with many other infections and not indicative of malaria alone. More severe symptoms or residence or travel in endemic area will raise the likelihood of such symptoms being caused by malarial infection. Health care providers in endemic areas should recognize flu like symptoms as possible malaria cases. Malaria is most often clinically diagnosed with a microscope and a blood smear. A Giemsa stain is performed and the parasites are visible inside RBC. The picture is a part of a chart for helping clinic staff to recognize different Plasmodium species. Malaria can also be diagnosed with PCR, but due to the rural locations and lack of funds microscopy is still the preferred method of diagnosis. ELISA is not capable of diagnosing current infection, but can tell a lot about infection history. Information on this slide from CDC webpage: http://www.cdc.gov/malaria/diagnosis_treatment/diagnosis.htm#clinical http://mosquito.who.int/docs/hbsm_diagnosis.htm

Treatment Chloroquine most common and effective drug used to treat malaria Causes nausea, blurred vision, and in some cases neurological dysfunction and seizures Treatment of malaria is generally Chloroquine, most common and effective drug used to treat malaria. Chloroquine is a harsh drug and can cause nausea, blurred vision, and in some cases neurological dysfunction and seizures. The mechanism by which chloroquine and other quinolines inhibit P. falciparum is not well understood. They appear to inhibit the production of hemozin, the malarial pigment. Information on this page from World Health Organization’s Malaria page http://mosquito.who.int/cmc_upload/0/000/015/372/RBMInfosheet_1.htm http://www.globalphar.com/chl_pic.php

Roll Back Malaria Insecticide treated nets Indoor residual spraying Intermittent preventatives Prompt treatment Roll Back Malaria is an international program aimed at reducing and ultimately eliminating malaria infections all around the world. They recommend that insecticidal nets be used at least over beds where children sleep. Long lasting insecticidal nets which can be used for up to 3 years without being treated again are highly recommended. Use of insecticidal nets have been shown to cut infection of children by half. However, production of such nets is low and unlikely to be able to meet demand for several years to come. Roll Back Malaria also supports indoor spraying in urban areas as a way to greatly reduce malaria. However, this requires a well organized spraying strategy and considerable funding and therefore is not feasible in many rural areas. In an effort to reduce the burden on pregnant women and reduce preventable still births, pregnant women in endemic areas are intermittently treated at various times during pregnancy with the full effective dose of antimalarial drugs. This reduces viral load and increases birth weigh of the baby. Swift, accurate diagnosis and prompt effective treatment as always are important factors in helping to meet the goal of eradicating malaria. Information on this slide from roll back malaria website: http://www.rbm.who.int/cgi-bin/rbm/rbmportal/custom/rbm/home.do http://www.rbm.who.int/cgi-bin/rbm/rbmportal/custom/rbm/home.do

Mosquitofish http://www.clevelandaquariumsociety.org/mosquitofish.jpg Another important weapon in fighting malaria is this adorable guppy looking fish pictured above, commonly known as the mosquitofish. Gambusia affinis are native to the southeastern United States and adapt well to a wide range of temperatures. They reproduce every six weeks during the summer and produce between 50 and 100 offspring each time. Mosquitofish can live up to three years and grow to a maximum of three inches. These tiny fish can consume up to 100 mosquito larvae every day of their lives. Information on this slide from website about mosquitofish :http://www.lawestvector.org/MosquitoFish.htm http://www.clevelandaquariumsociety.org/mosquitofish.jpg

Life cycle of Plasmodium Falciparum The lifecycle of P. falciparum is complex. It reproduces sexually in the mosquito host and a sexually in the human host. Understanding the complete lifecycle is important in understanding the pathogenicity of P. falciparum. Information for this section from: Sherman, Irwin Malaria: parasite biology, pathogenesis and protection ASM press, Washington DC 1998. http://post.queensu.ca/~forsdyke/pfalcip01.htm

Sporozoits in the liver Pores Kupffer cells Reproduction It is not known how Plasmodium falciparum crosses the liver endothelia. The natural pores of the liver are much too small for P. falciparum to simply pass through. It is possible that P. falciparum is actively taken up by the Kupffer cells. If this is indeed what occurs no mechanism has been suggested. It is known that the parasite is rapidly removed from the blood stream by the liver in the first 24 hours. Sporozoits reproduce asexually in the liver and release merozoits (daughter cells) into the blood stream where they insert themselves in an unknown manner into the red blood cells. Information for this section from: Sherman, Irwin Malaria: parasite biology, pathogenesis and protection ASM press, Washington DC 1998. http://k12education.uams.edu/scvlab/history.htm

Sporozoits in the blood In the red blood cells merozoites continue to reproduce a sexually and every 2-3 days they lyse the host’s red blood cells and reenter the blood stream in search of new cells to infect. It is this reproductive cycle that produces the characteristic fever of malaria. When the parasites are sequestered in the blood cells the patient experiences no fever. When the blood cells are ruptured and P. falciparum are free in the blood stream the patient experiences a high fever. P. falciparum loose in the blood stream causes an inflammatory response which will be explained in further detail in the section on pathogenicity. Then as P. falciparum reinserts itself into blood cells the fever drops causing the patient to sweat. Information for this section from: Sherman, Irwin Malaria: parasite biology, pathogenesis and protection ASM press, Washington DC 1998. http://astuasbalas.blogspot.com/2004_02_01_astuasbalas_archive.html

Gametocyte development Sexual commitment Sequestered in bones Resistance to quinine Longevity . Cells are committed to sexual development during the preceding asexual generation rather than differentiating upon invasion of red blood cells. The cues that stimulate Plasmodium falciparum to produce offspring capable of sexually reproducing are linked to high parasite density. Immature gametocytes are sequestered in bone marrow. P. falciparum remain in the bone marrow undetected by the immune system for the 9-12 days that it takes gametocytes to develop. Mature gametocytes are not affected by standard treatments and may survive in the human host at levels high enough to cause infection in mosquitoes for up to 22 days. This makes treatment more challenging as a person could continue to be a carrier for the disease for nearly a month after receiving treatment. “Female” gametocyte http://www.bepast.org/dataman.pl?c=lib&dir=docs/photos/malaria

Gametocyte Infectivity Temp drop Red blood cells lysed Xanthurenic acid and exflagellation eye color Gametogenesis is stimulated by a temperature drop of between 2 and 5 C. This occurs when the fever has broken and the temperature of the patient returns to normal. Mosquitoes then bite a person and drink blood infected with Plasmodium falciparum gametes. The development of a flagella by the male gamete is triggered by xanthurenic acid which is a by product of tryptophan metabolism. In anopheles mosquitoes some eye color mutants have reduced xanthurenic acid production and are therefore less susceptible to Plasmodium falciparum infection. Information for this section from: Sherman, Irwin Malaria: parasite biology, pathogenesis and protection ASM press, Washington DC 1998. http://lozere.org/perso/malaria/parasit.htm

Gametogenisis Rapid morphological changes “male” gametocyte Once in the mosquito host the gametes continue to mature. Rapid morphological changes can produce up to 60% abnormal or dysfunctional microgametocytes or “male” gametocytes. In a functional microgametocyte both the axoneme (central core of the flagella) and the nucleus enter the macrogametocyte or female gametocyte. Information for this section from: Sherman, Irwin Malaria: parasite biology, pathogenesis and protection ASM press, Washington DC 1998. “male” gametocyte http://www.ksu.edu/parasitology/625tutorials/Plasmodium01.html

Ookinets 2 divisions Anatomy of a mosquito midgut The newly formed zygotes undergo two meiotic divisions and have four haploid genome copies within each nucleus. Ookinets , which are motile zygotes, enter the epithelial lining of the mosquito midgut and migrate to the basal lamina. Here the Ookinets stop moving and becomes Oocysts. The mosquito is an ideal place for further parasite development. The mid-gut is made up of a single layer of epithelial cells separating the lumen , or inner open space of an insect, from the hemocoel ,outer cavity. Resting between the basement membrane and the basal lamina, the Oocyst is undisturbed by the blood mediated immune response of the mosquito. http://www.bc.edu/schools/cas/biology/news/encounter/

Oocysts Sporozoit budding Number of sporozoits per oocyst When mature sporozoits bud from the Oocyst. When production is complete the Oocyst ruptures and releases sporozoites into the blood of mosquitoes. The estimated number of sporozoits produced per Oocyst is between 1 and 10 thousand. Information for this section from: Sherman, Irwin Malaria: parasite biology, pathogenesis and protection ASM press, Washington DC 1998. http://www.biosci.ohio-state.edu/~parasite/plasmodium.html

Sporozoits Migration Mature sporozoits move with a gliding motility and invade the saliva glands of mosquitoes. Fewer than 25 sporozoits are transmitted in the average bite of the mosquito. Information for this section from: Sherman, Irwin Malaria: parasite biology, pathogenesis and protection ASM press, Washington DC 1998. http://www.malarlife.dfl.org.za/malaria%20virus%20photos.htm

Mosquito bites person… http://post.queensu.ca/~forsdyke/pfalcip01.htm

Pathogenicity The next section discusses some of the disease causing agents and some ways in which P. falciparum evades the immune system. http://www.nmm.ac.uk/server/show/conMediaFile.5757/outputRegister/lowhtml

Toxins Resistance Hemozin TNF-alpha IL-1 and IFN-gamma The functions of most of the products of P. falciparum are not known. It is known that they are resistant to treatment with proteases. P. falciparum uses hemoglobin as a source of energy and produces hemozin to digest hemoglobin, this toxin is stored in the pigment of P. falciparum . This pigment has been linked to over production of tumor necrosis factor alpha, the gamma interferon and interuleukin-1. These are important and natural parts of human immune systems, but over production can lead to fever and the destruction of healthy host cells. Information for the following slides adapted from: Chen, Q., M. Schlichtherle, and M. Wahlgren. 2000. Molecular aspects of severe malaria. Clin. Microbiol. Rev. 13:439-450 http://www.wordsources.info/words-mod-malaria.html

Tumor Necrosis factor TNF is a protein that is stimulated by certain toxins (in this case the malarial pigments). TNF attacks abnormal cells and has been shown to attack and destroy small tumors, hence the name tumor necrosis factor. It was once explored as a therapy for cancer (before chemo and radiation therapy), but adverse side effects such as fever stopped this research. TNF is also involved in inflammatory response and triggering interuleukin-1 production. The fever associated with malaria has been attributed to the overproduction of TNF. When P. falciparum are released into the blood stream over production of TNF causes fever and joint pain, etc. Information for this slide from: http://www.sigmaaldrich.com/cgi-bin/hsrun/Suite7/Suite/Suite.hjx;start=Suite.HsViewHierarchy.run?Detail=Product&ProductNumber=SIGMA-T0157&VersionSequence=1 http://www.farm.kuleuven.ac.be/anafar/lab/protein/tnf.htm

Toxicity and pathogenicity Proteins and cell membranes Infection by P. falciparum also radically changes the cell membrane of red blood cells. The membrane of infected cells becomes rigid and the parasite creates channels through the membrane in order to transport nutrients into the cell. Protein components of the cell membrane are digested by the parasite and are replaced by the “knobs” (electron rich protrusions of ~100 micrometers). The knobs are used to bind to uninfected RBCs and to the walls of veins and arteries. This is known as rosetting and can lead to some of the most severe complications of malaria, including cerebral malaria, where such rosettes occur in the brain. Information for the following slides adapted from: Chen, Q., M. Schlichtherle, and M. Wahlgren. 2000. Molecular aspects of severe malaria. Clin. Microbiol. Rev. 13:439-450

Rosetting Five receptors Immune system evasion? There are five receptors on RBC which are thought to be involved with the formation of rosetts. They include blood group antigens A and B, CD-36, compliment receptor 1and HS-like GAGs (heparan sulfate glycosaminoglycans). Rosettes formed in blood types A and B are larger, tighter and stronger than those formed in persons with O type blood. Blood type A is most often affected by severe malaria. (I had better stay out of Africa!) P. Falciparum also binds uses knobs to both IgG and IgM. The reason for having accumulations of IgM is not precisely known, but it is theorized that such accumulations hinder the access of antibodies specific to infected cells and thus help malaria to evade the immune system. Information for the following slides adapted from: Chen, Q., M. Schlichtherle, and M. Wahlgren. 2000. Molecular aspects of severe malaria. Clin. Microbiol. Rev. 13:439-450

Antigenic Variation Opportunities abound Malaria has many tools to evade the immune system. P. falciparum has a very high degree of antigenic variation, making it difficult for the immune system to recognize malaria. P. falciparum has two different ways in which to vary which antigens it expresses. The fist way in which this might occur is during the sexually reproducing stage in the lifecycle when P. Falciparum recombines genetic material. This has unlimited potential to change the genome of P. Falciparum. The second way in which antigenic variation can occur is through variable genes and point mutations during asexually reproducing stages of the lifecycle. P. Falciparum o has several families of variable antigenic genes. These are var family, the rosettin/ rif family, and the p60 family. With such a large amount of variability available to malaria it is no wonder that it can successfully evade the immune system and cause many recurring infections if not properly treated. Information for the following slides adapted from: Chen, Q., M. Schlichtherle, and M. Wahlgren. 2000. Molecular aspects of severe malaria. Clin. Microbiol. Rev. 13:439-450 http://www.lovetoparty.co.nz/images/SURPRISE.jpg

Crossover http://www.stanford.edu/group/Urchin/GIFS/crossover.jpg P. falciparum sexually reproduces in the midgut of mosquitoes. There are 14 chromosomes in all P. Falciparum but the size of these chromosomes varies greatly. Cross over is common during sexual reproduction and occurs in P. falciparum in the same way in which it occurs in all other eukaryotes. Crossover events have been known to occur between two different chromosomes suggesting that the same functions are on more than one chromosome at a time. Such redundancy also increases the likelihood of morphologically different, but functionally identical proteins. Information for the following slides adapted from: Chen, Q., M. Schlichtherle, and M. Wahlgren. 2000. Molecular aspects of severe malaria. Clin. Microbiol. Rev. 13:439-450 http://www.stanford.edu/group/Urchin/GIFS/crossover.jpg

Var Family http://www.niaid.nih.gov/dir/labs/lmvr/mgs.htm There are approximately 40-50 genes in the var family with a few exception they are extremely variable. The var genes are scattered throughout the chromosomes, but concentrated on the 4, 7, and 12 chromosomes. Using the high variability in these regions at least 2% of individuals vary their antigenic expression each generation. These genes are thought to be involved with resistance to chloroquine and to help P. falciparum evade the host’s immune system. The exact mechanism by which quinolines act upon P. falciparum is unknown, however, it is thought that quinolines interfere with the production of the malarial pigments and thus the production of hemozin. Quinolines are absorbed by the food vacuoles and resistance is thought to involve a mechanism for removing quinolines from the vacuole. Some of the important genes involved in this appear to be pfcrt found on chromosome 7 which encodes for vacuole proteins. Mutations at this sight are found in 100% of all resistant strains of P. falciparum. The efficacy of the resistance is greater when a mutation also occurs at a sight known as pfmdr1 (P. falciparum multidrug resistance gene) Information for the following slides adapted from: Chen, Q., M. Schlichtherle, and M. Wahlgren. 2000. Molecular aspects of severe malaria. Clin. Microbiol. Rev. 13:439-450 Dorsey, G., M. R. Kamya, A. Singh, and P. J. Rosenthal. 2001. Polymorphisms in the Plasmodium falciparum pfcrt and pfmdr-1 genes and clinical response to chloroquine in Kampala, Uganda. J. Infect. Dis. 183:1417-1420. http://www.niaid.nih.gov/dir/labs/lmvr/mgs.htm

Research About Malaria The next section explores what research is being done to combat malaria.

PO phosphoriboprotein One factor being explored for possible vaccine is Ribosomal phosphoprotein. Ribosomal phosphoprotein is found in all eukaryotes including protozoa. PO is found on the surface of P. falciparum and adults living in endemic areas (those most likely to have an acquired immunity) have show antibodies to Plasmodium falciparum P0 phosphoriboprotein (Ribosomal phosphoprotein) . Antibodies of this nature were shown to prevent invasion of RBC. Mice treated with this protein and then infected with P. falciparum showed immunity to P. falciparum infection. This gives researchers hope that PFPO could be used to create a vaccine against malaria entering the blood stream. Antibodies from adults with acquired immunity were used to inoculate mice who were then challenged with P. falciparum. Mice receiving the treatment showed considerable resistance to infection by P. falciparum. Information for this slide from: K. Rajeshwari, Kalpesh Patel, Savithri Nambeesan, Monika Mehta, Alfica Sehgal, Tirtha Chakraborty, and Shobhona Sharma The P Domain of the P0 Protein of Plasmodium falciparum Protects against Challenge with Malaria Parasites Infect Immun. 2004 September; 72(9): 5515–5521. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=15322057

Vaccines New treatment Acquired immunity challenges Not much funding is available for the development of new treatments for malaria. The locations where malaria is endemic are some of the poorest countries in the world and development of new medicines is not seen as profitable by drug companies. As a consequence no new treatments have been developed for over 10 years. Repeated infection has afforded some individuals immunity, but this is short lived unless the person is frequently exposed to P. falciparum. As yet there is no vaccine for malaria and there are many challenges facing researchers in this area. Some of the most challenging aspects for development of vaccines are: high variability due to var genes and the expression of different surface proteins at different stages during infection of P. falciparum. Information for these slides from: Raghunath D. Malaria vaccine: Are we anywhere close? J Postgrad Med [serial online] 2004 50:51-54 http://web.uct.ac.za/depts/mmi/jmoodie/vacc2.html

Prevention of Liver stage infection There are other vaccine avenues also being explored. Several antigens expressed during the blood stream and liver stage of P. falciparum have been shown to elicit an immune response in humans. The study showed that liver stage antigen 3 was highly immunogenic and a good candidate for use in a vaccine to prevent the invasion of RBC by P. falciparum. Immune memory of the antigens (especially LSA3) lasted up to 9 months when tested in chimpanzees. Chimpanzees were inoculated with the proteins and immune memory was measured. The chimpanzees were not challenged with P. falciparum. The greatest advantage in developing such a vaccine is that several epitopes, surface portion of antigen that binds with antibodies, might be used at the same time. This will help to overcome the advantage gained by P. falciparum through antigenic variation. However, unless such a vaccine could be modified to last longer than 9 months it would only be useful for travelers and would be of little use to people living in endemic areas. Information for this slide from: Pouniotis DS, Proudfoot O, Minigo G, Hanley JC, Plebanski M. Long-Term Multiepitopic Cytotoxic-T-Lymphocyte Responses Induced in Chimpanzees by Combinations of Plasmodium falciparum Liver-Stage Peptides and Lipopeptides Infection and Immunity, August 2004, p. 4376-4384, Vol. 72, No. 8 http://www.med.nyu.edu/parasitology/faculty/ufrevert.html

Vaccinating mosquitoes Another possibility for a vaccine does not actually target P. falciparum in humans, but in mosquitoes. There are proteins on the surface of gametes and ookinets that may prove useful in formulating a vaccine that protects mosquitoes from infection. Antibodies to these proteins prevent the parasite from taking up residence in the midgut of mosquitoes and forming oocysts. However, in order for such vaccines to reach mosquitoes they must be combined with efforts to vaccinate people living in endemic areas. Information on this slides from Michael A. Riehle, Prakash Srinivasan, Cristina K. Moreira and Marcelo Jacobs-Lorena. Towards genetic manipulation of wild mosquito populations to combat malaria: advances and challenges. The Journal of Experimental Biology 206, 3809-3816 (2003) http://www.bigthings.ca/manitoba/pictures/1mos1.jpg

Paratransgenesis Another way of making mosquitoes immune to P. falciparum is paratransgenesis. Paratransgenesis is the manipulation of symbiotic bacteria such as E.coli to make the host immune to a pathogen. Bacteria are engineered to produce proteins or peptides that either block binding of or kill parasites. There are several bacteria known to live in the anopheles midgut including Escheria, Pseudomonas , and bacillus . When fed with E. coli that produced antibodies to P. berghei, Anopheles mosquitoes showed a reduction in oocyst formation of 95%. Information on this slides from Michael A. Riehle, Prakash Srinivasan, Cristina K. Moreira and Marcelo Jacobs-Lorena. Towards genetic manipulation of wild mosquito populations to combat malaria: advances and challenges. The Journal of Experimental Biology 206, 3809-3816 (2003) http://www.mbl.edu/Astrobiology/Riley/image/E.coli.gif http://www.invivo.fiocruz.br/celula/imagens/bacillus.jpg

Engineering mosquitoes 3 stages AgAper promoter vitellogenin promoter salvitory promoters Researchers are also studying the possibility of making mosquitoes less genetically susceptible to P. falciparum infection. The AgAper1 promoter produces proteins that are stored in the epithelial cells of the midgut and are released shortly after feeding. Inserting a gene here is being studied as a possible way of preventing formation of oocysts. The vitellogenin promoter has been studied as a way to kill sporozoits which have budded from oocysts, however, products of this region have a short period of effectiveness, only two days long. Sporozoits do not bud for up to ten days. This is not an entirely useless idea however, as continuing feeding by mosquito stimulates this promoter. Two promoter regions in the saliva glands have also been researched, but both are weak and therefore not good candidates. The possibility of some response controlled by the mosquitoes immune system is also being researched. Information on this slides from Michael A. Riehle, Prakash Srinivasan, Cristina K. Moreira and Marcelo Jacobs-Lorena. Towards genetic manipulation of wild mosquito populations to combat malaria: advances and challenges. The Journal of Experimental Biology 206, 3809-3816 (2003) http://jeb.biologists.org/cgi/content/full/206/21/3809/FIG2

Other ways to reduce infection http://www.wmconnolley.org.uk/bees/ http://k12education.uams.edu/scvlab/history.htm Transgenic mosquitoes expressing bee venom known as phospholipidase A2 have also been shown to resist oocyst formation by up to 87%. Synthetic molecules have also been studied as ways of reducing susceptibility. Anopheles mosquitoes with a synthetic gene expressing SM1 peptide were found to have 82% reduction in formation of oocysts. Information on this slides from Michael A. Riehle, Prakash Srinivasan, Cristina K. Moreira and Marcelo Jacobs-Lorena. Towards genetic manipulation of wild mosquito populations to combat malaria: advances and challenges. The Journal of Experimental Biology 206, 3809-3816 (2003)

Future challenges Funding Research Distribution One of the major challenges in eradicating malaria is lack of funding. There is still much that we do not know about P. falciparum and how it infects humans. Another major challenge is lack of organization and funding for distribution of existing resources to treat malaria.

Conclusion "I have not failed. I've just found 10,000 ways that won't work." Thomas Alva Edison Malaria is not inevitable, it can be eradicated if we devote ourselves to research and effective treatment.

Sources See notes section for a list of references arranged by slide number. The information for slides 3,4,6,8 was from World Health Organization’s Malaria page http://mosquito.who.int/cmc_upload/0/000/015/372/RBMInfosheet_1.htm The information for slide 5 was from the CDC webpage about malaria and pregnancy: http://www.cdc.gov/malaria/pregnancy.htm The information for slide 7 was from the CDC webpage about diagnosing malaria: http://www.cdc.gov/malaria/diagnosis_treatment/diagnosis.htm#clinical The information for slide 9 was from the Roll Back Malaria: http://www.rbm.who.int/cgi-bin/rbm/rbmportal/custom/rbm/home.do Information on slide 10 was from a webpage about the mosquitofish: http://www.lawestvector.org/MosquitoFish.htm Information for this section (slides 11-20) from: Sherman, Irwin Malaria: parasite biology, pathogenesis and protection ASM press, Washington DC 1998. Information for slides 22,24,25,26,27,28 from: Information for these slides from: Raghunath D. Malaria vaccine: Are we anywhere close? J Postgrad Med [serial online] 2004 50:51-54 Information for slide 23 from: http://www.sigmaaldrich.com/cgi-bin/hsrun/Suite7/Suite/Suite.hjx;start=Suite.HsViewHierarchy.run?Detail=Product&ProductNumber=SIGMA-T0157&VersionSequence=1 Additional information for slide 24 about resistance to quinolines fromDorsey, G., M. R. Kamya, A. Singh, and P. J. Rosenthal. 2001. Polymorphisms in the Plasmodium falciparum pfcrt and pfmdr-1 genes and clinical response to chloroquine in Kampala, Uganda. J. Infect. Dis. 183:1417-1420. Information for slide 30 from: K. Rajeshwari, Kalpesh Patel, Savithri Nambeesan, Monika Mehta, Alfica Sehgal, Tirtha Chakraborty, and Shobhona Sharma The P Domain of the P0 Protein of Plasmodium falciparum Protects against Challenge with Malaria Parasites Infect Immun. 2004 September; 72(9): 5515–5521. Information for slide 31 from: Raghunath D. Malaria vaccine: Are we anywhere close? J Postgrad Med [serial online] 2004 50:51-54 Information for slide 32 from: Pouniotis DS, Proudfoot O, Minigo G, Hanley JC, Plebanski M. Long-Term Multiepitopic Cytotoxic-T-Lymphocyte Responses Induced in Chimpanzees by Combinations of Plasmodium falciparum Liver-Stage Peptides and Lipopeptides Infection and Immunity, August 2004, p. 4376-4384, Vol. 72, No. 8 Information for slides 33-36 from: Michael A. Riehle, Prakash Srinivasan, Cristina K. Moreira and Marcelo Jacobs-Lorena. Towards genetic manipulation of wild mosquito populations to combat malaria: advances and challenges. The Journal of Experimental Biology 206, 3809-3816 (2003)