Is a Circumsporozoite Protein based vaccine an applicable preventative against Malaria?
Is a Circumsporozoite Protein based vaccine an applicable preventative against Malaria?
1.1 The Problem
Malaria is caused by five species of parasites of the genus: Plasmodium that affects humans (P. falciparum, P. vivax, P. ovale, P. malariae and P. knowlesi). “Malaria due to P. falciparum is the most deadly form and it predominates in Africa; P. vivax is less dangerous but more widespread, and the other three species are found much less frequently”.An estimated 3.3 billion people were at risk of malaria in 2011, with persons living in sub-Saharan Africa having the highest risk of contracting malaria: children under five years of age and pregnant women are most severely affected.[1]
Malaria parasites are transmitted to humans by the bite of infected female mosquitoes of more than 30 anopheline species [1]. Anopheles mosquitoes breed in water and each species has its own breeding preference; for example some mosquitoes prefer hollow bodies of fresh water, such as rice fields, hoof prints and puddles. Transmission occurs more often in places where the mosquito lifespan is greaterand in an area that is populated by humans. For example, the long lifespan and strong human-biting habit of the African vector species is why more than 90% of the world 's malaria deaths are in Africa. [2]
When a fertilized female Anopheles mosquito taking a blood meal injects an infective strain of Plasmodium into the human bloodstream, the single celled sporozoite travels to a liver cell, where it divides by mitosis as a pre-erythrocyte to release thousands of blood-infective merozoites within 1 to 2 weeks. In each infected red blood cell a multiplication cycle of 8 to 15 times is repeated every 48 to 72 hours. After several blood cycles, daughter gametes develop, which are transported to: fresh mosquitoes, mature male and female gametes and thousands of sporozoites. Sporozoites reach the salivary glands, become virulent within 10-30 days of blood meal, and are transported into new
1.1 The Problem
Malaria is caused by five species of parasites of the genus: Plasmodium that affects humans (P. falciparum, P. vivax, P. ovale, P. malariae and P. knowlesi). “Malaria due to P. falciparum is the most deadly form and it predominates in Africa; P. vivax is less dangerous but more widespread, and the other three species are found much less frequently”.An estimated 3.3 billion people were at risk of malaria in 2011, with persons living in sub-Saharan Africa having the highest risk of contracting malaria: children under five years of age and pregnant women are most severely affected.[1]
Malaria parasites are transmitted to humans by the bite of infected female mosquitoes of more than 30 anopheline species [1]. Anopheles mosquitoes breed in water and each species has its own breeding preference; for example some mosquitoes prefer hollow bodies of fresh water, such as rice fields, hoof prints and puddles. Transmission occurs more often in places where the mosquito lifespan is greaterand in an area that is populated by humans. For example, the long lifespan and strong human-biting habit of the African vector species is why more than 90% of the world 's malaria deaths are in Africa. [2]
When a fertilized female Anopheles mosquito taking a blood meal injects an infective strain of Plasmodium into the human bloodstream, the single celled sporozoite travels to a liver cell, where it divides by mitosis as a pre-erythrocyte to release thousands of blood-infective merozoites within 1 to 2 weeks. In each infected red blood cell a multiplication cycle of 8 to 15 times is repeated every 48 to 72 hours. After several blood cycles, daughter gametes develop, which are transported to: fresh mosquitoes, mature male and female gametes and thousands of sporozoites. Sporozoites reach the salivary glands, become virulent within 10-30 days of blood meal, and are transported into new
Bibliography: (1) World Health Organization (2012). World Malaria Report 2012. Switzerland: World Health Organization. 1. (2) World Health Organization (3) Patricia Schlagenhauf-Lawlor (2007). Traveler 's Malaria. 2nd ed. USA: Pmph USA. 70. (4) Nicholas A. V. Beare et al (2006). MALARIAL RETINOPATHY: A NEWLY ESTABLISHED DIAGNOSTIC SIGNS IN SEVERE MALARIA. The American Society of Tropical Medicine and Hygiene. 75 (5), p790-797. (5) NHS. (2012). Symptoms of malaria. Available: http://www.nhs.uk/Conditions/Malaria/Pages/Symptoms.aspx. Last accessed 29th Jan 2013. (6) Mvi Path. (2013). Life cycle of the malaria parasite. Available: http://www.malariavaccine.org/malvac-lifecycle.php. Last accessed 31st Jan 2013. (7) Kent E. Kester et al (2001). Efficacy of Recombinant Circumsporozoite Protein Vaccine Regimens against Experimental Plasmodium falciparum Malaria. The Journal of Infectious Diseases. 183 (4), p640-647. (8) Bob Snow et al. (2004). New vaccines are not the only answer to malaria. Available: http://www.scidev.net/en/opinions/new-vaccines-are-not-the-only-answer-to-malaria.html. Last accessed 30th Jan 2013. (9) Sarah Boseley. (2011). Malaria vaccine set to save millions of lives, but who will fund it? Available: http://www.guardian.co.uk/society/2011/oct/18/malaria-vaccine-save-millions-lives. Last accessed 31st Jan 2013. (10) Path.org. (2009). Investing in Vaccines for the Developing World. Available: http://www.ghtcoalition.org/files/VAC_vacc_invst_fs.pdf. Last accessed 4th Feb 2013. (11) Vasee Moorthy et al. (2002). Malaria Vaccines. British Medical Bulletin. 62 (1), 59-72. (12) IRIN. (2011). AFRICA: Malaria vaccine could have extra benefits. Available: http://www.irinnews.org/Report/93024/AFRICA-Malaria-vaccine-could-have-extra-benefits. Last accessed 5th Feb 2013. (13) Joseph O Fadare et al. (2010). Ethical issues in malaria vaccine clinical trials: A principle-based approach. Annals of Tropical Medicine and Public Health. 3 (1), 35-38. (14) Francesco Ricci. (2012). Social Implications of Malaria and Their Relationships with Poverty. Mediterranean Journal of Haematology and Infectious Diseases. 4 (1), 1. (15) Debora MacKenzie. (2012). Malaria vaccines could make the disease worse. Available: http://www.newscientist.com/article/dn22125-malaria-vaccines-could-make-the-disease-worse.html. Last accessed 7th Feb 2013. (16) Liza Gross. (2012). Could Vaccines Breed Super-Virulent Malaria? Available: http://blogs.plos.org/biologue/2012/07/31/could-vaccines-breed-super-virulent-malaria/. Last accessed 7th Feb 2013. (17) Centres for Disease Control and Prevention. (2012). Insecticide-Treated Bed Nets. Available: http://www.cdc.gov/malaria/malaria_worldwide/reduction/itn.html. Last accessed 9th Feb 2013. (18) Roll Back Malaria. (2012). Nets and insecticides. Available: http://www.rollbackmalaria.org/psm/netsandinsecticides.html. Last accessed 9th Feb 2013 (19) (17) Centres for Disease Control and Prevention (20) Jane Taylor (2001). Microorganisms and Biotechnology. 2nd ed. Cheltenham: Nelson Thornes. 175-178. (21) Frederique A Jacquerioz et al. (2010). Drugs for preventing malaria in travellers. Available: http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD006491.pub2/full. Last accessed 9th Feb 2013. (22) J. A. Stoute et al. (1998). Long-Term Efficacy and Immune Responses with the RTS,S Malaria Vaccine.Journal of Infectious Diseases. 178 (4), 1139-1144.