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Infectious Diseases Essay

African trypanosomiasis or sleeping sickness as many call it is a parasitic disease that can be contracted by either human or animals. The disease is transmitted by the tsetse fly which can be found all over Africa but the ones contaminated with the disease are found in region of sub-Saharan Africa. The disease has been said to have been in Africa since way back in the 14th century and one of the first epidemics that was recorded happened in 1901 in which a “devastating epidemic had erupted in Uganda, killing more than 250,000 people, about two-thirds of the population in the affected lake-shore areas” (CDC).

According to the World Health Organization the disease covers 36 countries and 60 million people. The majority of the affected population live in remote areas of sub-Saharan Africa with little access to health care clinics which is why in these rural area the disease often goes untreated and misdiagnosed. The distribution of African trypanosomiasis is related to where the Tsetse fly lives which happens to be many parts of Africa. Not all species of Tsetse flies transmit the disease and there is no explanation of why certain regions with populations of Tsetse flies do not have a trace of the sleeping sickness disease.

According to the WHO “The disease develops in areas ranging from a single village to an entire region. Within an infected area, the intensity of the disease can vary from one village to the next”. Of the 60 million or so people in threat of obtaining the disease each year only few cases in relation to that number will be reported so many believe since the disease occurs in predominately remote areas many cases are going undiagnosed. There are two forms of human African trypanosomiasis depending on the parasite “Trypanosoma brucei gambiense (T. b. g. ) is found in west and central Africa… nd Trypanosoma brucei rhodesiense (T. b. r. ) is found in eastern and southern Africa” (WHO). Of the two T. b. g. currently accounts for 95% of reported cases and the other form T. b. r. currently only accounts for 5% of reported cases. The main way the disease is contracted is from a bite of an infected tsetse fly but that is not the only way. The WHO lists that a pregnant mother can pass on the infection to a fetus, in some instances other blood sucking insects have transmitted the disease as well as accidental infections from pricks of contaminated needles.

In the first stafe of infection, the haemolymphatic phase, the trypanosomes multiply which causes fever, headaches, joint pain and itching. In the second stage known as the neurological phase the parasites infect the central nervous system which causes “changes of behavior, confusion, sensory disturbances and poor coordination and disturbance of the sleep cycle, which gives the disease its name” (WHO). The two forms of the disease have different impacts on the infected individuals health and livelihood. The more common form of the parasite T. . g. causes a chronic infection. A person infected with this form of the disease can be infected for months or years without any major signs or symptoms and when the symptoms do emerge the patient is already in the second stage of the disease. The other form of the disease T. b. r. which is less common only causes an acute infection with the first symptoms showing in few months or weeks after the initial infection. Regardless of which form of the disease the infected individual has if gone untreated the disease can be fatal.

The treatment for the disease depends on the stage of the infection, the sooner it’s found the easier it is to treat. If found in the first stage the drugs used of are low toxicity and easy to administer and consists of Pentamidine for T. b. g. and Suramin for T. b. r. For the second stage of infection there are four drugs that can be administered but are all toxic and complex to administer. Melarsoprol for both forms, Eflornithin for T. b. g and most recently the combination of nifuritimox and eflornithine have been used to treat severe cases.

Thanks to the efforts of organizations like the World Health Organization the upward trend of new cases of the disease is no longer a trend. In fact According to the WHO in ” In 2009, after continued control efforts, the number of cases reported has dropped below 10,000 (9878) for first time in 50 years”. In epidemic areas it is estimated that 20% of the population are infected by the disease which has a serious economic impact because of the damage it does to the workforce in these regions.

Malaria is one of the oldest diseases in mankind and it is believed by many that most of today’s malaria originated in West and Central Africa. According to “Recent molecular studies have found evidence that human malaria parasites probably jumped onto humans from the great apes, probably through the bites of vector mosquitoes” (Carter). As man evolved and spread throughout the world they carried diseases along with them and such how malaria came to appear all across the world. Cases of malaria have been dated back thousands of years to ancient civilizations: Sumerian and Egyptian texts dating from 3,500 to 4,000 years ago mention about fevers and splenomegaly suggestive of malaria. (The enlarged spleens of Egyptian mummies are believed to have been caused by malaria). It appears that P. falciparum had reached India by around 3,000 years ago. It is believed that malaria reached the shores of the Mediterranean Sea between 2,500 and 2,000 years ago and northern Europe probably mainly between 1,000 and 500 years ago. The waves of invasions that swept across the continents helped the cause of malaria parasite as well.

By the Middle Ages, Kings and feudal lords had the best wetlands under their control, but in turn had to fear marshes as breeding grounds of plagues and incurable fevers” (Rich) So basically the spread of Malaria was facilitated by the travel of man and of course the right environment for the mosquitoes to breed. Malaria is contracted only through bites of Anopheles mosquitoes, or infected mosquitoes and the severeness of the disease depends on the host, environment and the mosquito itself.

There are about 20 different Anopheles species of mosquitoes and most of them bite at night and breed in shallow freshwater such as puddles, rice fields and hoof prints. The transmission of the disease is worse with an older or more developed mosquito because the parasite the causes the disease is more developed. It also depends on where the mosquito like to bite humans, for example “the long lifespan and strong human-biting habit of the African vector species is the underlying reason why more than 85% of the world’s malaria deaths are in Africa” (WHO).

Contracting the disease is also a matter of immunity, which is developed after years of exposure in areas with a moderate to severe amount of cases. Finally the climate of region and rainfall patterns have a lot to do with the number of occurrences at a certain time. Once contracted the symptoms of malaria don’t appear for seven or more days, usually ten to fifteen days. The first signs of the disease are fevers, headaches, chills and vomiting which may be hard to pin on malaria. Though if not treated in twenty-four hours malaria can become a serious illness which often leads to death, if not that brain damage.

Infected individuals if not treated can die and most of the victims that do die are children and often times children receive brain damage from the severe fevers brought on by Malaria. The disease is very dangerous to pregnant women as well because the disease can be transferred to the unborn baby, “Non-immune pregnant women are at risk as malaria causes high rates of miscarriage and maternal death rates of 10–50%. Malaria can result in miscarriage and low birth weight, especially during the first and second pregnancies. An estimated 200,000 infants die annually as a result of malaria infection during pregnancy” (WHO).

Other people at risk include people with HIV or AIDS as well as travelers to regions with malaria because they have no immunity. The cure or treatment for malaria includes artemisinin bases combination therapy or ACT. If treated and diagnosed early the chances of death and other injuries are greatly reduced as well the spread of the infection to others. There are many ways to prevent the disease as well for travelers chemoprophylaxis can be taken to prevent the malaria disease. As for those living in high infection areas the best form of prevention would be the control of the mosquito population.

Many of the people who live in these areas sleep under nets treated with insecticide and spray some type insecticide in the home a few times a year. Since malaria is so easily spread and it affects millions of people a year it does have a significant economic impact, especially in areas of high rates of infection. According to the World Health Organization malaria “can decrease GDP by as much as 1. 3% in countries with high levels of transmission. Over the long term, these aggregated annual losses have resulted in substantial differences in GDP between countries with and without malaria, particularly in Africa”.

Malaria takes a deep toll on areas with substantial amounts of poverty because the people themselves don’t have money for treatment and medicine and the local government have to pour in more than half of their budget to deal with the epidemic. Like malaria, West Nile virus is a disease spread by mosquitoes and the conditions of those infected can range from mild to severe. According to the National Center of Biotechnology information the virus was first found in 1937 in Uganda and first found in the United State in New York in 1999.

Researchers believe the virus is spread when a mosquito bites an infected bird and then goes on to bite a person or an animal. The Center for Disease Control states that the virus has been found in “Africa, Europe, the Middle East, west and central Asia, Oceania (subtype Kunjin), and most recently, North America”. In the most extreme cases West Nile virus can cause a condition called encephalitis which causes swelling of the brain. Symptoms of the West Nile virus are said to be similar to the flu and include fever, headache, stiff back and neck, muscle and joint aches, rash, swollen glands and general tiredness.

These symptoms can last several weeks and for serious cases, in which people can get tremors, convulsions, muscle weakness, vision loss, numbness and paralysis, symptoms can be permanent. According to the CDC about 80 percent of people infected with the virus will not show any symptoms at all and only about one in 150 people will develop serious illnesses. West Nile virus can be spread in other ways than just a mosquito bite such blood transfusion, organ transplant, breastfeeding and during pregnancy from mother to child. Symptoms of the virus typically develop between three and fourteen days after the initial bite of the mosquito.

The treatment of West Nile Virus depends on the severity of the symptoms and there is no specific treatment. Those who have only mild symptoms such as fever and aches don’t require much medical attention for these symptoms will pass on their own. For more serious cases it is definitely necessary for the infected individual to go to a hospital or get some kind of medical help. Since the disease is a virus there are no antibiotics or medicines that will kill the disease instead if worst outcome happens which is encephalitis, antiviral medicine used for treatment of HIV have been known to been use.

An individual with serious symptoms best chance is to get to a hospital to receive general treatment such as intravenous fluids and other things which reduce the chance of things getting worse. West Nile virus has great social and economic impacts, mainly because of the cost of treatment and lack of treatment for severe cases. According to the CDC the cost of West Nile virus related health care in 2002 was approximately $200 million. Since there are many recent outbreaks compared to other diseases a lot of money has been spent on prevention and control problems.

In the United States the Center for Disease Control has invested a lot time in helping the nation deal with any future epidemics by working to develop vaccines, creating and distributing educational and informative material to the media and public, helping states with mosquito prevention and control programs, and by coordinating a nationwide database with information regarding the virus. Yellow fever is another disease spread through the bite of a mosquito and can be found in tropical and subtropical areas of South America and Africa.

It is called yellow fever because some of the people who get infected will be affected by jaundice which makes them yellow. The first recorded appearance of the disease was in 1648 in Yucatan which is in South America. According to article titled Yellow Fever: A Disease that Has Yet to be Conquered ” Major outbreaks also occurred in Europe, e. g. in 1821 in Barcelona with several thousand victims. 1878, about 20,000 people died in an epidemic in the Mississippi River Valley and the last major outbreak in the US occurred in 1905″ (Higgs).

The number of yellow fever cases has increased over the past two decades because of “declining population immunity to infection, deforestation, urbanization, population movements and climate change” (WHO). The mosquito carries the yellow fever virus from host to host usually between monkeys and from monkeys to human and then to more humans. According to the World Health Organization there are three types of yellow fever sylvatic (jungle) yellow fever, intermediate yellow fever, and urban yellow fever.

Jungle yellow fever occurs in tropical rainforest and with monkeys that get infected by the mosquitoes and then the mosquitoes bite humans who enter the forest. Intermediate yellow fever occurs in humid or semi-humid places parts of Africa, usually in somewhat rural villages and it is the most common type of outbreak in Africa. Urban yellow fever occurs in densely populated areas and causes large epidemics because of high number of non-immune people and large numbers of the infected mosquito. Once the disease is contracted the virus stays dormant for three to six days followed by a potential two phase infection.

The first phase which is the acute phase causes fever, muscle pain, backache, headache, shivers, loss of appetite, nausea and vomiting. Most individuals in the acute phase get better and these symptoms are gone after three to four days. On the other hand: “15% of patients enter a second, more toxic phase within 24 hours of the initial remission. High fever returns and several body systems are affected. The patient rapidly develops jaundice and complains of abdominal pain with vomiting. Bleeding can occur from the mouth, nose, eyes or stomach. Once this happens, blood appears in the vomit and feces.

Kidney function deteriorates. Half of the patients who enter the toxic phase die within 10 to 14 days, the rest recover without significant organ damage” (WHO). It is hard to diagnose yellow fever because in the early stages of the infection it can be confused with malaria, dengue hemorrhagic fever, leptospirosis, viral hepatitis as well as poisoning. According to the CDC there an estimated 200,000 cases of yellow fever, causing 30,000 deaths worldwide each year and up to 50% of severely affected persons without treatment will die from yellow fever.

Forty-five countries in Africa and Latin America with a combined population of over 900 million are at risk. There is no cure for yellow fever the treatment is aimed at reducing the symptoms for the comfort of the patient, although there is a highly effective and affordable vaccination. Those who contract the disease are advised to go to a hospital where they can get antibiotics for infections caused by the disease and supportive care for the severe symptoms. The best way to treat yellow fever is to prevent it with the vaccine which “appears to provide protection for 30–35 years or more.

The vaccine provides effective immunity within one week for 95% of persons vaccinated” (WHO). Currently organizations like the WHO and UNICEF are highly involved in helping areas of the yellow fever epidemic in Africa where the disease is the most prominent. Through these agencies the vaccine is routinely administered to any individual in need that is at least nine months or older. All of the four diseases covered in this paper have qualities that make them something to be worried about.

Out of the four the two most important diseases in my opinion would have to be malaria and yellow fever due to the fact that these two diseases affect more people in a broad area and cause more casualties than West Nile virus and African trypanosomiasis. Out of malaria and yellow fever I would have to say that malaria is a more important disease because it infects a large amount of people, in a larger global scope, causes the most death and has the greatest social and economic impact.

Overall I believe that malaria is the most important disease but for certain categories some of the other three diseases have the greatest mpact and damage. In terms of geographical distribution the four diseases in order of smallest distribution to largest distribution would be African trypanosomiasis, yellow fever, West Nile virus, and malaria has the greatest distribution. African trypanosomiasis is only found in areas with infected tsetse flies which only includes countries predominately in Africa and most occurrences are in sub-Saharan Africa in very remote and rural areas. Yellow fever can be found in tropical areas of Africa and South America but still infects are large amount of people.

West Nile virus has a pretty large distribution, in the past decade or so there has been large numbers of cases popping up all over the United States but has in the past been found in Africa, Asian, Europe as well as the Middle East. West Nile virus can happen wherever there are infected mosquitoes so the potential distribution is very large. Malaria also has a large distribution which can be found all over the world, wherever there are infected mosquitoes, but it mainly found in Africa and there is quite of lot of cases found in Asia.

Of the four diseases they are all contracted by a bite from an infected insect, all of them except for African trypanosomiasis which is contracted by the tsetse fly are contracted from bites of infected mosquitoes. All of the diseases have many different symptoms that lead to death if not treated and yellow fever is the hardest to diagnose because it shares symptoms with many other infections. Even though West Nile virus can be dead over 80% of infected individuals will not show any symptoms and go on to be fine.

African trypanosomiasis has many tell tale symptoms if caught early treatment is simply but if it caught in the second stage things are a lot harder and symptoms often lead to death. Malaria also has many symptoms and the first symptoms are very broad and are difficult to diagnose as malaria, if these symptoms are not treated within twenty-four hours death can occur. I believe yellow fever has the worst symptoms of all because 15% of the infected will not get better after the acute infection and become severely ill.

Treatment must fast and concise which is hard because the early symptoms can be confused with malaria, hepatitis, poisoning and many other infections. These four diseases have severe health impacts on individuals who get infected and all can lead to death or serious permanent conditions. African trypanosomiasis which affect the infected person’s central nervous system which if untreated leads to death, the disease can cause a chronic infection. Malaria is disease that some can build an immunity to but for those who don’t have it catching it can be deadly.

Malaria often causes high fevers which in turn causes brain damage in many individuals especially children. Children especially in Africa have high rates of contracting and dying from malaria and even if they survive there is a host of permanent condition it can cause. Conditions such as cognitive impairments from the brain damage, anemia, intracranial pressure and abnormal postures. Most people who get sick from West Nile virus are fine and get over the flu like symptoms within a week but those who don’t get better sometimes develop encephalitis.

Encephalitis is the swelling of the brain and is very painful and cause other conditions that lead to death. Yellow fever has many severe health impacts as well and is called yellow fever because of the jaundice it causes to some of the infected. Severe cases result in deterioration of the kidneys which why half the people with a serious case will die. The health impacts of malaria are the most important because they have a higher chance of happening compared to the other diseases.

In 2008 there were 247 million cases of malaria and almost one million deaths most of which belonged to children in Africa. According to the World Health Organization 85% of the world’s malaria deaths are in Africa and accounts for 2. 23% of deaths worldwide. Next up yellow fever which has an estimate 200,000 cases per year with 30,000 casualties. In the areas of infection, Africa and South America, there roughly 900 million people at risk of contracting the disease, 90% of the infections occur in Africa. 009 was the first time in 50 years that cases of African trypanosomiasis fell below 10,000, the problem with putting numbers to this disease is that the majority of the infected individual live in very remote and rural area so there isn’t proper surveillance on the epidemic. Since the most current outbreak of West Nile virus was in the US the number from the Center of Disease Control and Prevention lists only those statistics. In 2010 there were 1,021 cases with only 57 deaths caused by the virus which is a tad higher than 2009 but still an improvement over past years.

Now for the treatment comparison, first African trypanosomiasis can treated with different medications depending on the stage of the disease but many of the medicine have some bad side effects. Early treatment of malaria greatly reduces the chances of death and is usually done by administering a combination therapy which consists of antibiotics. Over the last decade or so it has been noticed that malaria is developing a drug resistance because of patients discontinuing the use of the medicine prematurely.

West Nile virus doesn’t really have much treatment in the early stage people usually get through the flu like symptoms on their own but in severe cases hospitalization is necessary. If encephalitis occurs treatment consists of making the symptoms more tolerable for the patient. Yellow fever is similar to West Nile virus in the way that in the severe cases there really isn’t much of a treatment. The best treatment for yellow fever would be the vaccine which is 95% effective and lasts anywhere from 30-35 years.

West Nile virus and yellow fever do not have treatments like the other diseases because they are caused by virus and are not bacterial infection that can be treated with antibiotics. In regards for a need for a better treatment, West Nile virus and yellow fever are the two more important diseases. After researching all four diseases it was not difficult for me to conclude that malaria was the most important and harmful. Not only does it affect people all over the world it has the largest number of cases and deaths in the world.

For a disease that is caused by a mosquito bite and is responsible for 2. 23% of deaths in the world is unbelievable and a bit horrifying. According to the World Health Organization a child in Africa dies every forty five seconds because of malaria. The disease has serious health impacts on an infected individuals health and if one doesn’t die from the disease it still cause many permanent health conditions especially with developing children. With just saying all of that malaria seems bad but not much worse than diseases like yellow fever but then consider the economic impact of the disease.

The World Health Organization has stated that “Malaria causes significant economic losses, and can decrease gross domestic product (GDP) by as much as 1. 3% in countries with high levels of transmission”. A disease like that makes poverty stricken countries stuck because more than half of their budget is going to battling the epidemic. There are also many social implication such as for all those children who get brain damage from the disease their lives will permanently be limited. Many of them will not be able to get a professional job which further hurts the economy of wherever they are from.

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