Malaria phase. The merozoite starts by becoming a trophozoite

Malaria is a fatal infectious disease that harms people all around the world, mainly in tropical/ saharan locations.  The risk of malaria increases with the climate change and changes in land such as through: logging, road building, mining, and agricultural/irrigation project.  The disease can be contracted from the bite of a female anopheles mosquito infected with the plasmodium parasite.  Out of a plethora of plasmodium parasites only 5 cause the disease in humans: falciparum, vivax, malariae, ovale, and knowlesi.  After being bit by the plasmodium infected mosquito tiny, worm like sporozoites leave the insects saliva and enter the humans bloodstream to infect red blood cells.  Minutes is all it takes for the sporozoites to reach the liver where they begin to mature by asexual reproduction and attack hepatic parenchymal cells.  In 1-2 weeks falciparum, malariae, and knowlesi change from sporozoites to merozoites as the host cells die while vivax and ovale take another route.  Taking a longer amount of time, from months to years, these diseases become hypnozoites and go dormant.  This means instead of dividing right away they cause a delay from the time initially infected to experiencing the symptoms.  These diseases are generally not inside the red blood cells or asymptomatic.  Ovale invade red blood cells of all age and vivax invade young, immature red blood cells.  Vivax also uses an erythrocyte surface receptor known as the Duffy antigen and those with sickle cell anemia protect against this disease as they don`t the Duffy.  Other diseases like thalassemia and G6PD make the parasite more likely to die from oxidative stress.  Merozoites that have been released into the blood each bind to a surface receptor and invade a red blood cell.  Malariae prefers older red blood cells as does knowlesi and falciparum has no preference.  Once the merozoite is inside a red blood cell it asexually reproduces which is an ongoing process for 2-3 days.  The disease then goes into a series of transformation known as the erythrocytic phase.  The merozoite starts by becoming a trophozoite which has a ring like shape, the ring then grows and is referred to as a late trophozoite, finally the trophozoite becomes a schizont that continues to grow due to the ingestion of hemoglobin. At this point the schizont is now in the processes of mitosis, replicating a numerous amount of merozoites, preparing to enter the bloodstream. There are some diseases however that instead of going through the erythrocytic phase undergo gametogony where they divide and produce gametocytes.  Gametocytes are sexual forms, either male or female, that are small and sausage shaped.  These remain in the red blood cell until it potentially gets taken out by another female anopheles mosquito resulting in the process occuring over again to another person.  It’s important to know that contracting malaria is just one way of getting infected.  A mother that winds up with malaria can also put her fetus at risk of contracting the disease at birth which is know as congenital malaria.  Malaria can also be transmitted by blood meaning that the disease can spread through an organ transplant, a blood transfusion, or from sharing needles/syringes.  Falciparum causes the worst infections as it generates a sticky protein that coats the surface of the red blood cell victim and gives the appearance of little “knobs” on the cell.  This then will cause the red blood cells to clump together inside the body and block the flowage of blood vessels.  Cytoadherence infected cells cannot flow into the spleen, a vital organ, which can cause hemolytic anemia and ischemic damage resulting in organ failure. When the brain becomes affected, cerebral malaria, can cause altered mental status, seizures, and potentially a coma. This can also result in blocked blood flow to the lungs and kidneys.  When the liver is affected, bilious malaria, results in diarrhea, vomiting, jaundice, and liver failure. Primarily symptoms, ranging from high grade fever to death, are caused due to the rupture of red blood cells.  “Common symptoms of malaria include: shaking chills that can range from moderate to severe, high fever, profuse sweating, headache, nausea, vomiting, abdominal pain, diarrhea, anemia, muscle pain, convulsions, coma, bloody stools.”  (Burke, 2017).  These symptoms typically develop within 10 days- 4 weeks following the infection.  With nausea each disease acts differently in the body.  With malariae this symptom lasts around 72 hours, vivax and ovale last around 48 hours, knowlesi lasts about 24 hours, and falciparum differs anywhere from 24-48 hours.   Malaria has the greatest impact in Sub- Saharan Africa with 90% of the 300-500 million annual cases of malaria.  As previously stated malaria is a fatal disease, “In 2015 about half of the population world wide were at risk according to The World Health Organization (WHO).” (Shane, n.d.).  This quote confirms how dangerous malaria is if half the world wide population was at risk.  Generally speaking uncomplicated malaria infections are resolved with treatment. While many are at risk this blood disease is responsible for at least 1 million deaths in Africa each year, “The World Health Organization (WHO) reports malaria is responsible for one in five deaths of African children under age 5 every year.” (Shane, n.d.).  While the disease takes a toll on the people of Africa physically, it also affects the infected and the country economically.  The annual costs of malaria are estimated to be higher than 2 billion US dollars and slows the countries economic growth up to 1.3 percent per year.    As malaria is mostly impacting the lives of those living in Africa it also affects those in the US, “In the United States, the Centers for Disease Control and Prevention (CDC) report 1,700 cases of malaria annually. Most cases of malaria develop in people who travel to countries where malaria is more common.” (Burke, 2017).  Those living in rural areas or in poverty are also at a big risk because they have less access to prevent and treat the deadly infection.Another thing that makes this disease so dangerous is that once contracting the disease it doesn’t provide the once infected humans with immunity.  It may provide some tolerance but malaria can reoccur.  Malaria can reoccur from ineffective treatment not curing the infection which is common where there is high antimalarial resistance.  It can also relapse meaning that blood may have been cleaned of merozoites but the hypnozoites continue to persist in the liver.  Another way of malaria coming back is from reinfection which can happen because, as said before, obtaining the disease once does not provide immunity and a new infection can be caused.  Doctors are capable to diagnose the disease during appointments by reviewing health history, searching for potential travel to tropical climates and a physical exam.  In the physical exam your doctor can see whether or not your spleen or liver are enlarged or if you show symptoms of malaria.  They may need to perform a blood test as well to confirm your diagnosis.  If it is necessary to perform a blood test the results will show if you have malaria, what type, if its caused by a parasite that’s adapted to certain drugs, if you’ve developed anemia, and if the disease has impacted your vital organs.    With plasmodium having a complicated life cycle it proposes a challenge to develop a vaccine for malaria treatment.  With there being 5 different disease that humans are vulnerable to researchers must discover the disease, life stage of parasite, and what to combine in the vaccine.  “There is currently no commercial vaccine available to prevent malaria. Due to the diversity of the Plasmodium Species and the P. falciparum species being the most deadly parasite, most efforts are currently directed toward a P. falciparum vaccine. RTS,S/ASO1 is the most advanced candidate as a viable vaccine.A phase 3 trial of RTS,S/ASO1 was completed and results published in 2015.”  (Balentine, 2017).  This quote proves that there is no specific vaccine to cure malaria due to the complexity of the disease however scientists are researching ways to help while developing other vaccines, “Pre-erythrocytic vaccines target the infectious phase and aim either to prevent the sporozoites from getting into the liver cells or to destroy infected liver cells. 15 The most significant challenge for a pre-erythrocytic vaccine is the time frame: sporozoites reach the liver less than an hour after being injected by the mosquito. As a result, the immune system has a limited amount of time to eliminate the parasite. Although most of the potential pre-erythrocytic vaccines are still in Phase I or Phase II trials, one vaccine is currently in Phase III trials and is showing promise: the RTS,S vaccine.” (n.a., 2017).  Scientists are developing the vaccine so its efficiency is higher than 50%. “Erythrocytic vaccines, or blood-stage vaccines, aim to stop the rapid invasion and asexual reproduction of the parasite in the red blood cells.”  (n.a., 2017).  The thought behind this is if the body can create antibodies against the antigen a feeding mosquito will take up some of the antibodies and digest them.  Once in the mosquitos stomach the antibodies and antigen will encounter one another and the antibodies will interfere with the development leading to the termination of the parasite. While traveling it is a good idea to take medication to prevent infection, “Four medications are commonly used in the USA to prevent malaria while traveling: Atovaquone/proguanil (Malarone), mefloquine (Lariam), chloroquine (Aralen), and doxycycline.” (Kohl, n.d.). As for treatments they are divided by stage of infection.  Therapeutic treatments goal is to eliminate merozoites in the erythrocytic phase.  Medications depend on age, pregnancy status, local malarial resistance patterns, plasmodium species, and severity of infection.  Gametocidal treatment is aimed at terminating gametocytes by preventing the spread of disease and creation of resistant parasite forms.  Radical treatment is targeting killing hypnozoites in the liver from P. Vivax and P. ovale infections. Prevention from housing this nasty infection is also anything that prevents mosquito bites.  Examples include: wearing full body clothing, sleeping in insecticide covered mosquito nets, and using indoor insecticide sprays.  This can also mean emptying stagnant water collections– since anopheles mosquitoes lay their eggs in shallow collections of water. In conclusion, malaria is an infectious disease posing a threat to mainly tropical/ sub- Saharan residents and travelers.  The disease can be contracted from female anopheles mosquito with a plasmodium parasite and through the transfer of blood.  There are 5 plasmodium diseases humans are susceptible to, impacting the body differently.  Malaria causes millions of deaths per year impacting those in sub- Saharan Africa. This disease does not have a specific vaccination however there is research, treatments, protective medications, and prevention tactics.