SGI Cell Biology Unit. Transparencies and Student Sheets

SGI Cell Biology Unit Transparencies and Student Sheets

Name Date Disease Information Sheet Tuberculosis Information Sheet Prevalence Deaths Geographic distribution Infection and Transmission Process Treatment and Prevention Mutation/Resistance Information Current issues/other information

HIV/AIDS Information Sheet Prevalence Deaths Geographic distribution Infection and Transmission Process Treatment and Prevention Mutation/Resistance Information Current issues/other information

Malaria Information Sheet Prevalence Deaths Geographic distribution Infection and Transmission Process Treatment and Prevention Mutation/Resistance Information Current issues/other information Cell Biology: World Health Student Sheet 1.1

Infectious Disease Data http://www.globalhealth.org/view_top.php3?id=228 DRAFT FOR TESTING PURPOSES ONLY Cell Biology: World Health Transparency 1.1

Examples of Cells Cell Biology: World Health Transparency 2.1

Sickle Cell and Malaria Distribution of Malaria Distribution of Sickle Cell Trait http://evolution.berkeley.edu/evolibrary/article/_0/history_19 DRAFT FOR TESTING PURPOSES ONLY Cell Biology: World Health Transparency 4.1

Venn Diagram of Cells and Microbes Cell Biology: World Health Transparency 5.1

Timeline of the History of Cells and the Germ Theory Cell Biology: World Health Transparency 6.1

Lab Materials Similar to Koch s Cell Biology: World Health Transparency 7.1

The Phospholipid Bilayer Cell Biology: World Health Transparency 8.1

Mixing Substances Indicator Water Glucose Starch Iodine Glucose test strip Cell Biology: World Health Transparency 9.1

Folding Structures of Proteins DRAFT FOR TESTING PURPOSES ONLY Cell Biology: World Health Transparency 12.1

Name Date Sample Procedure: The Effect of Temperature on Enzyme Function 1. Mix 20 ml of lactase enzyme solution with 20 ml of room temperature milk in a beaker. 2. Add 10 ml of glucose solution to Cup A of the SEPUP tray. Add 10 ml of plain room temperature milk to Cup B of the SEPUP tray. 3. Create tables for recording data. Control Glucose solution Plain room temperature milk Color of glucose test strip Temperature ( C) Control (no heating) 40 60 80 100 Color of glucose test strip (milk+enzyme solution) 4. Dip one glucose test strip into the glucose solution in Cup A. Remove it and let it sit for 3 minutes. 5. Record the results in the table. 6. Repeat Steps 3 and 4 for the plain room temperature milk in Cup B and the milk+enzyme solution in the beaker at room temperature. 7. Heat the milk+enzyme solution in the beaker on a hot plate to 40 C. Dip one glucose test strip into the solution. Remove it and let it sit for 3 minutes. 8. Continue heating the mixture. Repeat Step 7 for each of the temperatures. 9. Clean and dry the SEPUP tray. Cell Biology: World Health Student Sheet 13.1a

Name Date Sample Procedure: The Effect of ph on Enzyme Function 1. Add 10 ml of glucose solution to Cup A of the SEPUP tray. Add 10 ml of plain room temperature milk to Cup B of the SEPUP tray. 2. Create tables for recording data. Control Glucose solution Glucose solution + acid Plain room temperature milk Color of glucose test strip Acid (# of drops) Color of glucose test strip ( milk + lactase enzyme) Control (no acid) 5 10 15 20 3. Dip one glucose test strip into the plain room temperature milk in Cup A. Remove it and let it sit for 3 minutes. 4. Record the results in the table. 5. Repeat Steps 3 and 4 for the glucose solution in Cup B. 6. Rinse and dry the SEPUP tray. 7. Add 5 ml of the lactase enzyme solution to Cup A of the SEPUP tray. Add 5 ml of milk to the lactase solution in the Cup. 8. Add 5 drops of acid to the solution in Cup A. Repeat Steps 3 and 4 for the milk solution + acid. 9. Repeat Step 3 and 4 for 10, 15, and 20 drops of acid added to the solution in Cup A. 10. Clean and dry the SEPUP tray. Cell Biology: World Health Student Sheet 13.1b

How Enzymes Function Cell Biology: World Health Transparency 13.1

Name Date Diagram of HIV Infection Cell Biology: World Health Student Sheet 15.1

Name Date The Immune Response Cell Biology: World Health Student Sheet 17.1

Name Date Stem Cell Differentiation Cell Biology: World Health Student Sheet 17.1

The Organization of Multicellular Organisms Cell Biology: World Health Transparency 17.1

Cell Cycle Game Key: Blood-forming Stem Cell in the Bone Marrow If you are in G 1 or G 0 and roll: Then... 2, 3, 4, 5, 6 More blood cells are needed. Grow by adding some clay to your cell and move to the S phase. 7, 8 More blood cells are needed. Your cell is a slow grower. Skip one turn. Then grow by adding some clay to your cell and move to the S phase. 9, 10 No blood cells are needed right now. Stay in G 1 and roll again next turn. 11, 12 Blood cells are not needed, but your cell has lost its normal controls. Roll the number cubes again. If you roll 1-8, the immune system has recognized and destroyed the cancer cell, so start over in G 1 with a new blood stem cell. If you roll 9-12, move your cell to S and continue through the cell cycle as a cancer cell. Ask your teacher for a copy of Student Sheet 18.1e. If you are in S and roll... Then... 2, 3, 4, 5, 6, 7 Your cell s DNA replicates perfectly. Advance to G 2 phase. 8, 9, 10 There was a DNA replication error. Skip one turn while repairs are made. Then advance to G 2. 11,12 There was a DNA replication error. It cannot be repaired. Your cell awaits destruction. Begin again next round with a new bloodforming cell in G 1. Cell Biology: World Health Student Sheet 18.1a

If you are in G2 and roll... Then... 2, 3, 4, 5, 6, 7, 8 All is well. Cyclin, which regulates progress through the cell cycle, has accumulated. Grow a little more, enter M right away, and roll again as part of the same round. 9, 10, 11 Cyclin accumulates slowly. Stay in G 2 for this round. In the next round, grow a little more, enter M, and roll again as part of the next round. 12 Something has gone wrong with the factors that regulate your cell s cycle. Your cell is stuck in G 2 and will be destroyed. Begin again next round with a new blood-forming cell in G 1. If you are in M and roll... 2, 3, 4, 5, 6, 7, 8, 9 Then... All is well. Your cell s chromosomes line up and progress through mitosis and cytokinesis. Separate your cell into two daughter cells. Set one cell aside in your plastic cup, where it will differentiate into an adult blood cell. Move the other cell forward to continue to G 1 as a blood-forming stem cell. 10,11 There was a mitotic error. Your cell s chromosomes did not separate properly. Await destruction. Next round, start over as a new blood-forming cell. 12 Mitosis was completed, but cytokinesis did not work properly. Await destruction. Begin again next round with a new blood-forming cell in G 1. Cell Biology: World Health Student Sheet 18.1a

Cell Cycle Game Key: Liver Cell If you are in G 1 or G 0 and roll: 2, 3, 4, 5, 6, or 11 Then... No liver cells are needed. Move to G 0 or stay there if you are already there. 7, 8 Liver cells are needed! Grow by adding some clay to your cell and move to S. 9, 10 Liver cells are needed, but your cell is growing slowly. Skip one turn, then add some clay to your cell and move to the S phase. 12 More liver cells are not needed, but your cell has lost its normal controls. Roll the number cubes. If you roll 1-8, the immune system has recognized and destroyed the cancer cell, so start over in G 1 with a new liver cell. If you roll 9-12, move your cell to S and continue through the cell cycle as a cancer cell. Ask your teacher for a copy of Student Sheet 18.1e. If you are in S and roll... Then... 2, 3, 4, 5, 6, 7 Your cell s DNA replicates perfectly. Advance to G 2 phase. 8, 9, 10 There was a DNA replication error. Skip one turn while repairs are made. Then advance to G 2. 11,12 There was a DNA replication error. It cannot be repaired. Your cell awaits destruction. Begin again next round with a new liver cell in G 1. Cell Biology: World Health Student Sheet 18.1b

If you are in G2 and roll... Then... 2, 3, 4, 5, 6, 7, 8 All is well. Cyclin, which regulates progress through the cell cycle, has accumulated. Grow a little more, enter M right away, and roll again as part of the same round. 9, 10, 11 Cyclin accumulates slowly. Stay in G 2 for this round. In the next round, grow a little more, enter M, and roll again as part of the next round. 12 Something has gone wrong with the factors that regulate your cell s cycle. Your cell is stuck in G 2 and will be destroyed. Begin again next round with a new liver cell in G 1. If you are in M and roll... 2, 3, 4, 5, 6, 7, 8, 9 Then... All is well. Your cell s chromosomes line up and progress through mitosis and cytokinesis. Separate your cell into two daughter cells. Set one cell aside in your plastic cup, where it will remain in G 0. Move the other cell forward to continue to G 1 and another round of the cell cycle. 10,11 There was a mitotic error. Your cell s chromosomes did not separate properly. Await destruction. Begin again next round with a new liver cell in G 1. 12 Mitosis was completed, but cytokinesis did not work properly. Await destruction. Begin again next round with a new liver cell in G 1. Cell Biology: World Health Student Sheet 18.1b

Cell Cycle Game Key: Nerve Cell If you are in G 1 or G 0 and roll... Then... 2, 3, 4, 5, 6 You are a nerve cell. You cannot divide. You enter G 0 permanently. Skip 1 turn. Then ask your teacher if you can start over as a skin cell. 7, 8, 9 You are a nerve cell. You cannot divide. You enter G 0 permanently. Skip 1 turn. Then ask your teacher if you can start over as a liver cell. 10, 11, 12 You are a nerve cell. You cannot divide. You enter G 0 permanently. Skip 1 turn. Then ask your teacher if you can start over as a bloodforming cell. Cell Biology: World Health Student Sheet 18.1c

Cell Cycle Game Key: Skin Cell You are a skin stem cell. Skin stem cells can divide to give two stem cells, or one or both can begin differentiation to become a skin cell. If you are in G 1 or G 0 and roll... Then... 2, 3, 4, 5, 6 Skin cells are needed. Grow by adding some clay to your cell and move to the S phase. 7, 8 Skin cells are needed. Your cell grows slowly. Skip one turn. Then grow by adding some clay to your cell and move to the S phase. 9, 10 No skin cells are needed now. Stay in G 1 and roll again next turn. 11, 12 More skin cells are not needed, but your cell has lost its normal controls. Roll the number cubes. If you roll 1-8, the immune system has recognized and destroyed the cancer cell, so start over in G 1 with a new skin cell. If you roll 9-12, move your cell to S and continue through the cell cycle as a cancer cell. Ask your teacher for a copy of Student Sheet 18.1e. If you are in S and roll... Then... 2, 3, 4, 5, 6, 7 Your cell s DNA replicates perfectly. Advance to G 2 phase. 8, 9, 10 There was a DNA replication error. Skip one turn while repairs are made. Then advance to G 2. 11,12 There was a DNA replication error. It cannot be repaired. Your cell awaits destruction. Begin again next round with a new bloodforming cell in G 1. Cell Biology: World Health Student Sheet 18.1d

If you are in G2 and roll... Then... 2, 3, 4, 5, 6, 7, 8 All is well. Cyclin, which regulates progress through the cell cycle, has accumulated. Grow a little more, enter M right away, and roll again as part of the same round. 9, 10, 11 Cyclin accumulates slowly. Stay in G 2 for this round. In the next round, grow a little more, enter M, and roll the number cubes. 12 Something has gone wrong with the factors that regulate your cell s cycle. Your cell is stuck in G 2 and will be destroyed. Begin again next round with a new blood-forming cell in G 1. If you are in M and roll... Then... 2, 3, 4, 5, 6, 7, 8, 9 All is well. Your cell s chromosomes line up and progress through mitosis and cytokinesis. Separate your cell into two daughter cells. Set one cell aside in your plastic cup, where it will differentiate into an adult skin cell. Move the other cell forward to continue to G 1 as a skin stem cell. 10,11 There was a mitotic error. Your cell s chromosomes did not separate properly. Await destruction. Next round, start over as a new blood-forming cell. 12 Mitosis was completed, but cytokinesis did not work properly. Await destruction. Begin again next round with a new skin stem cell in G 1. Cell Biology: World Health Student Sheet 18.1d

Cell Cycle Game Key: Cancer Cell If you are in G 1 or G 0 and roll... 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 Then... Grow and continue to the S phase. If you are in S and roll... Then... 2, 3, 4, 5, 6, 7, 8, 9 Your cell s DNA replicates perfectly. Advance all of your cancer cells to G 2 phase. 10, 11 There was a DNA replication error. Skip one turn while repairs are made. Then advance all of your cancer cells to the G 2 phase. 12 There was a DNA replication error, but all of your cancer cells continue into G 2 without repairing it. Cell Biology: World Health Student Sheet 18.1e

If you are in G 2 and roll... 2, 3, 4, 5, 6, 7, 8, 9, 10 Then... Grow a little more and continue to the M phase. Then roll again as part of this same round. 11, 12 Cyclin accumulates slowly. Stay in G 2 for this round. In the next round, grow a little more, enter M, and roll the number cubes. If you are in M and roll... 2, 3, 4, 5, 6, 7, 8, 9, 10 Then... Your cell s chromosomes line up and progress through mitosis and cytokinesis. Separate each of your cells into two daughter cells. Move them both ahead into G1, where they will continue through the cell cycle. 11 There was a mitotic error. Your cancer cell s chromosomes did not separate properly. Destroy one cancer cell. If you have cancer cells left, separate each one into two daughter cells and move them all ahead to G 1. If you have no cancer cells left, start over next round in G1 with the same kind of cell as you began with in Round 1. 12 Mitosis was completed, but cytokinesis did not work properly in one of your cancer cells. Await destruction. Destroy one cancer cell. If you have cancer cells left, separate each one into two daughter cells and move them all ahead to G 1. If you have no cancer cells left, start over next round in G1 with the same kind of cell as you began with in Round 1. Cell Biology: World Health Student Sheet 18.2e

Name Date Cell Cycle Record Sheet Cell Type: Record where your cell is at the start of each round of the activity. Then record what happens to your cell after rolling the number cubes. Round Cell Cycle Phase at Start (G 1, S, M, G 2, G 0 ) 1 G1 What happened to my cell Total number of cells at end of round 2 3 4 5 6 7 8 9 10 Cell Biology Student Sheet 18.2

Round Cell Cycle Phase at Start of Round (G 1, S, M, G 2, G 0 ) What happened to my cell Total number of cells at end of round 11 12 13 14 15 16 17 18 19 20 Cell Biology: World Health Student Sheet 18.2

Tuberculosis Official Fact Sheet Global Prevalence: More than 2 billion people are infected with the tuberculosis (TB) bacteria. Of those, 1 in 10 will become sick with active TB. Deaths (2006): 1.7 million, equal to 4,500 deaths per day Geographic Distribution: Each year, 1% of the global population is infected. 5-10% of those infected become sick or infectious.

Region Number infected with all forms of TB (thousands) percent of global total Percent of population infected with all forms of TB (estimate) Sub-Saharan 270,827 12.9 35 639 Africa Americas 161,889 7.7 18 41 Middle East & 157,810 7.5 29 108 North Africa Europe 133,118 6.3 15 62 South & 1,374,742 65.5 39 806 Southeast Asia Global 2,098,475 100 31.8 1656 Number of deaths per year (thousands) Transmission: TB is caused by the bacterium Mycobacterium tuberculosis. The bacterium can cause disease in any part of the body, but it normally enters the body though the lungs and resides there. TB is spread through aerosolized droplets in the air after infected people cough, sneeze or even speak. People nearby, if exposed long enough, may breathe in bacteria in the droplets and become infected. People with TB of the lungs are most likely to spread bacteria to those with whom they spend time every day including family members, friends and colleagues. When a person breathes in TB bacteria, the bacteria settle in the lungs. From the lungs, they can move through the blood to other parts of the body, such as the kidney, spine and brain. TB in these other parts of the body is usually not infectious. The only known reservoir for the bacteria is humans. Treatment and Prevention: People are advised to avoid close contact or prolonged time with known TB patients in crowded, enclosed environments like clinics, hospitals, prisons, or homeless shelters. Since tuberculosis is an airborne contagious disease, primary control is effected through finding and treating infectious cases and thus limiting the risk of acquiring infection. TB can almost always be cured with antibiotics. Known as first-line anti-tb drugs, some of the most common antibiotics used to treat TB are isoniazid (INH), rifampin (RIF), pyrazinamide (PZA) and ethambutol (EMB). There are

also second-line drugs to treat TB including fluoroquinolones and injectable antibiotics such as capreomycin, kanamycin and amikacin. Some of these drugs can cause side effects. Treatment for TB depends on whether a person has active TB or latent TB infection. Latent infection: A person who has latent TB might be given preventive therapy which aims to kill TB bacteria that currently are inactive to prevent them from causing active TB disease in the future. The usual prescription is a daily dose of INH for six to nine months -- possibly up to a year for some patients -- with periodic checkups to make sure the medicine is being taken as prescribed. Active infection: When a patient has active TB, several medicines are needed to do a better job of killing all of the bacteria and preventing them from becoming resistant to the drugs. Many of the first-line medications are available in a single tablet made up of a combination of several medications. Patients with active TB commonly receive a combination of several drugs -- most frequently INH plus two to three others -- usually for at least six months. The patient will probably notice improvements only a few weeks after starting to take the drugs. It is very important that patients take their medicine correctly for the full length of treatment. If the medicine is taken incorrectly or treatment is stopped, the patient might become sick again and will be able to infect others with TB. Challenges for treatment: 1. TB can exist in both a latent and active form inside the body. A latent infection can become active through a pre-existing infection or by new infection. An effective treatment must be able to target either situation. 2. Since people with TB are often also infected with HIV, a treatment must be effective in patients with a low number of helper T cells. Mutation and Resistance Information: If the first-line drugs are taken incorrectly or prescribed improperly, mulit-drug resistant (MDR) TB can develop. MDR-TB can be treated with second-line drugs that are more expensive and often are accompanied by more side effects. Treatment also is much longer than treatment for drug-susceptible TB. If secondline drugs are taken incorrectly or prescribed improperly, extensively drugresistant tuberculosis, XDR-TB can develop, leaving few treatment options available. XDR-TB is a relatively rare type of multi-drug resistant TB (MDR-TB) that is resistant to almost all drugs commonly used to treat drug-susceptible TB.

Current Issues/Other Information: Directly Observed Treatment, Short-Course (DOTS) is a proven system for TB treatment, based on accurate diagnosis and patients taking a full course of a cocktail of anti-tb drugs (which include isoniazid, rifampicin, pyrazinamide, streptomycin and ethambutol). In the DOTS system, a health care worker or community member volunteer ensures that patients are taking their prescribed treatment properly. Regular checkups are needed to monitor treatment progression. DOTS hinges on government commitment, detection, treatment, uninterrupted supply of anti-tb drugs and a monitoring and reporting system to evaluate treatment outcomes for each patient. It is especially important for those who are infected with both HIV and TB to discuss TB treatment options with a health care worker because some common medications for TB can interact with some antiretroviral drugs. The standard treatment regimen for TB patients who previously have been treated for the disease also may differ. Re-treatment cases also should be closely monitored because they have a higher likelihood of drug resistance, making treatment more difficult.

HIV/AIDS Official Fact Sheet Prevalence: Worldwide: Approximately 33 million adults and children. Deaths: Approximately 2 million worldwide in 2007, over 14 million total. Transmission: HIV infection is caused by a virus that enters the body in four main ways: 1. From an infected mother to child during pregnancy, birth, or breast feeding. 2. Through semen or vaginal fluid. 3. Shared needles or syringes contaminated with blood of an infected person. 4. Contact with blood from an infected person. The reservoirs for various strains of the virus are humans and non-human primates. Geographic distribution:

Region Sub-Saharan Africa Number infected with all forms of HIV/AIDS (thousands) percent of global total Percent of population infected with all forms of HIV/AIDS (estimate) 22,500 68 3 1,600 Americas 3,130 9 0.3 90 Middle East & North Africa 380 1 0.1 25 Europe 2,360 7 0.3 67 South & Southeast Asia 4,875 15 0.1 303 Global 33,200 100 0.5 2,100 Number of deaths per year (thousands) More than 95% of infected people live in countries with fewer resources. Treatment and Prevention: Current treatment: There are 26 different medications available as of 2006. Patients may take what is called a cocktail of at least three drugs at once: 1. Drug that stops virus RNA from being turned into DNA. 2. Drug that prevents virus from producing usable enzymes. 3. Drug that prevents virus from entering the host cells. This combination treatment is used because HIV can become resistant to any one of the drugs. The doses of the three drugs are carefully planned and timed so HIV does not have an opportunity to mutate. The FDA has approved a three drug pill that is taken once a day, called Atripla. Despite their effectiveness, these drugs do have side effects including a decrease in red and white blood cells, inflammation of the pancreas, and nerve damage.patients often take other drugs to combat the side effects of the cocktail drugs.

There are also drugs available to treat opportunistic infections such as eye infections, yeast and fungal infections, and pneumonia. Multiple treatments are being researched: Preventative vaccine made up of antibodies to block infection in people who are HIV negative: this approach has failed when mutated strains are introduced. Most of the vaccines currently in trials are therapeutic vaccines. These are designed to prevent the HIV infection from progressing to AIDS in infected patients. They may also prevent the infected person from passing the virus on to another person. These vaccines induce the cells to make more T cells to fight the infection. Researchers are studying exactly how HIV affects the immune system and how the disease progresses in different people in order to develop more effective drugs and vaccines. Since there is currently no vaccine available for HIV, the only way to prevent infection is to avoid the behaviors that lead to infection such as sharing needles. Often there is no way of knowing if a person is infected with HIV because many people who are infected do not show symptoms. Challenges for treatment: 1. HIV mutates rapidly. 2. The body never completely clears the infection naturally. Mutation and Resistance Information: HIV DNA changes rapidly through both mutation of the DNA and recombination of DNA. Recombination is the exchange of genetic information between two different types of viruses inside the cell. Even with a powerful cocktail of effective drugs, there is still no treatment that stops the rapid mutation of HIV. Resistance usually occurs in 3-5 years in individuals who take all of the doses of drugs as prescribed.

Current Issues/Other Information: In 2000, the World Bank declared that AIDS is a development crisis. Health care systems in countries with the highest number of HIV/AIDS patients are struggling to provide adequate health care. In sub-saharan Africa, schools are closing due to the deaths of thousands of teachers. Over 13 million children have been orphaned by HIV/AIDS. The number of orphans is expected to double by 2010. Agricultural production is affected because funds are being taken away from maintaining good irrigation and soil. This affects the economy in countries that rely on agricultural exports. It has been found that 90% of people today do not know that they are HIV positive. Therefore, it is important for people to get tested. In an effort to encourage testing, the World Health Organization has provided an easy, safe oral testing procedure that only requires saliva.

Malaria Official Fact Sheet Prevalence: 350-500 million cases Deaths: 1.1-1.3 million per year, mainly children---a child dies of malaria every 30 seconds. Risk 2.5 billion people at risk of malaria infection. Geographic Distribution: Worldwide in tropical areas but especially affecting a higher number of people in the sub-saharan Africa.

Region Number infected with all forms of Malaria (thousands) percent of global total Percent of population infected with all forms of Malaria (estimate) Number of deaths per year (thousands) Sub-Saharan 364,980 71 47 1,136 Africa Americas 3,690 1 0.4 65 Middle East & 11,860 2 2 1 North Africa Europe 550 0.1 0.1 11 South & 133,970 26 4 59 Southeast Asia Global 515,050 100 8 1,272 Mode of transmission: Human host/mosquito(vector)/human host: The female Anopheles mosquito bites her victim and then injects her saliva containing the Plasmodium parasite into the bloodstream of the human host. From there, the parasite travels to the liver and other organs. During this time, the victim may show no symptoms. From the liver, the parasites travel back to the bloodstream and enter red blood cells where they reproduce. Eventually the red blood cells rupture, releasing the parasites into the bloodstream. The only known reservoir for the parasite is humans.

Treatments: Antimalarial drugs are used to treat malaria. These drugs affect some of the chemical reactions important for the parasite survival. This ends up killing the parasite. Some drugs interfere with the synthesis of DNA. Malaria parasites have developed resistance to drugs, which means they are ineffective in killing the parasites. There are three factors that guide the treatment that is chosen for a patient: Prevention: 1. Which species of Plasmodium (P. vivax, P. falciparum, P. ovale, or P. malariae) is causing the infection 2. The type of symptoms the patient exhibits, which determines if the infection is uncomplicated or severe. 3. The drug sensitivity of the parasite causing the infection. There is no vaccine yet available for malaria. Mosquito nets sprayed with pesticides are used to kill the mosquitoes. The mosquitoes are becoming resistant to certain pesticides used to kill them, including DDT. Malaria parasites are very good at hiding from the host immune system. They do this by spending most of their time inside the host cells (liver and blood cells) so host immune cells have a hard time finding them and destroying them. They also change form multiple times throughout their life cycle inside the host, which makes it hard for the immune system to recognize the parasite. Scientists have been trying to develop vaccines that prevent the parasite from entering the host cells. Vaccines are being developed against the parasite surface receptors that it uses to enter the host cells.

Challenges for treatment: 1. The Plasmodium life cycle is very complex. It displays various antigens and has various effects on the body depending on which stage it is in. 2. A full natural immunity never develops. Mutation and Resistance Information: Plasmodium shows resistance to various antibiotics. The malaria parasites have developed strategies that make them resistant to antibiotics. Also the parasites are able to easily change the proteins that they express at their surface and this makes it difficult for the host immune system to recognize them as the invading parasite. Current Issues/Other Information: (1) Malaria causes a 1.3% average loss of yearly economic growth in countries with high transmission. It has longterm effects on the learning and attendance of children in school, and on attendance in the workplace. (2) The size and complexity of the parasite means that each infection presents thousands of antigens to the human immune system. Therefore, it has been difficult to determine which of these antigens is a useful target for vaccine development. (3) The parasite changes through several life stages even while in the human host, presenting a different subset of molecules for the immune system to combat at each stage. (4) The parasite has evolved a series of strategies that allow it to confuse, hide, and misdirect the human immune system. (5) It is possible to have multiple malaria infections of not only different species but also of different strains at the same time. In order to develop vaccines or drugs against processes that are unique to the parasite and not found in the host is an important step in fighting malaria. This is one of the reasons that it is important to understand the cell biology of the Plasmodium infection. Scientist who study the basic cell biology of Plasmodium infection try to understand the stages and processes that are part of the parasite life cycle, and perhaps identify new drugs that could prevent or cure malaria.