diseases West Nile virus, malaria, plague, and yellow fever. Specifically, it will discuss the history and distribution of the diseases in the United States or worldwide, and compare each of the diseases based on the categories above, as to which is most important individually and overall in terms of relative impact.
West Nile virus only appeared in the United States in 1999, but it has become quite a feared disease since then. The virus is contracted in humans from infected mosquito bites, and it can be deadly in people with weakened immune systems, like children and senior citizens. The symptoms of the disease can be minor, like headaches and an insignificant fever. These can increase to confusion, muscle weakness, high fever, and severe headache ("West Nile," 2004). They usually show up 3 to 14 days after being bitten. Symptoms that are more serious include brain swelling, coma, numbness, vision loss, and disorientation but these are far less common. Some people may not show any symptoms of the disease. Infected individuals may have severe impact on their health, and West Nile can kill those with weaker immune systems. By 2002, the disease had "exploded" across the nation, and in 2003, it showed up in mosquitoes in every state in the 48 contiguous states but Oregon and Washington. According to the Center for Disease Control (CDC), there were 9,858 human cases of the disease in 2003, and 262 deaths. This is down slightly from 284 deaths in 2002 ("West Nile," 2004). This spread all began from one dead crow discovered in New York City with the disease in 1999. It is incredibly common in any area where mosquitoes breed and live, and so, it is incredibly difficult to control. It can also spread by blood transfusion and from mother to unborn child. There is no known cure for the virus, and for mild cases, people simply get better as the disease progresses. The CDC is working on a vaccine against the virus, but does not expect it to be ready for several years ("West Nile," 2004). For more severe cases, treatment often includes hospitalization that might include intravenous fluids, help with breathing, and overall nursing care ("West Nile," 2004). The economic impact of this disease has been staggering. Treatment costs are not the problem; the problem is heavy spraying of infested mosquito areas in an attempt to control the disease. There are no cost estimates for how much mosquito spraying has cost throughout the nation, but the costs must be high to many communities. This disease is on the rise in the United States and around the world, and scientists expect it to continue to grow in the United States in 2004 and beyond. A panel of researchers note, "During 1999-2002, the virus extended its range throughout much of the eastern parts of the U.S.A., and its range within the western hemisphere is expected to continue to expand" (Campbell et. al., 2002, pg. 1). It is becoming much more common, and this can help aid public education about how to avoid the disease.
Often, the host dies from the disease. It can infect a variety of animals, including birds, "horses, bats, chipmunks, skunks, squirrels, and even alligators" (Ward, 2003, pg. B01), and so, it is quite easily spread throughout the animal kingdom, which is one reason the disease can spread across a continent so quickly. The social impact of the disease is difficult to measure, but outdoor activities are often impacted during the months the disease makes its' appearance (June through October, with a peak in September) (Ward, 2003, pg. B01). In areas that commonly support mosquitoes, residents are urged to stay inside during these months, or apply an insect repellent containing DEET (N, N-diethyl-meta-toluamide), according to the CDC. The easiest way to avoid the disease is to avoid mosquito bites, and so, the CDC recommends draining standing water in areas where mosquitoes breed, and around the home. West Nile virus is frightening because it can spread so quickly and because it is often difficult to detect.
Malaria is a disease making a comeback in the world. It was thought to have virtually disappeared, but because of concerns over pesticides and spraying to eradicate mosquitoes, the disease is common again, especially in Africa. Malaria, like West Nile, is contracted from infected mosquitoes (usually females). The mosquitoes contract the disease from the blood of infected persons they bite ("Malaria," 2004). One of the problems with control is that mosquitoes have developed resistance to the malaria parasite, and so they pass on the disease without succumbing to it (Tenenbaum, 2002, pg. 760). The symptoms of the disease include alternating fever and chills. "Malaria may also cause renal or pulmonary failure; cerebral malaria, which usually afflicts children and pregnant women, can cause coma, generalized convulsions, and death" (Tenenbaum, 2002, pg. 760). Clearly, the severe symptoms of malaria can cause serious impact on the health of the individual. The most serious impact is of course, death, but malaria is a silent disease, which makes it all the more dangerous. The malaria parasite can live in a person for years undetected if it is not treated effectively, or with the right drugs. The CDC notes, "Two types of parasites [...] have dormant liver stages that can remain silent for years. Left untreated, these liver stages may reactivate and cause malaria attacks ("relapses") after months or years without symptoms. Another type, [...] if left untreated, has been known to persist in the blood of some persons for several decades" ("Malaria," 2004). Obviously the fear of malaria returning, or infecting others with infected malarial blood is a serious impact on the individual with malaria. Infection is extremely common in areas where the disease occurs. Thought to be eradicated in the United States for decades, there were 1,337 cases of malaria and eight deaths in the U.S. during 2002 ("Malaria," 2004). In other countries around the world malaria is the leading disease causing death. One writer notes, "Today, malaria is resurgent in many tropical regions, especially Africa. According to the World Health Organization, each year it infects more than 300 million people and kills at least 1 million, mostly children" (Tenenbaum, 2002, pg. 760). There is no vaccine against malaria, but it can be treated effectively if caught early. There are malaria pills travelers can take to avoid contracting the disease if they travel to malaria-prone destinations. There are several different types of drugs to prevent and treat malaria, and the best one for each individual should be discussed with a health professional.
Clearly, the economic impact of malaria is staggering, considering the vast number of victims it claims every year around the world. While many of the worlds' poor simply die at home of the disease, many more are hospitalized with the disease, and the costs include treatment, medication, blood transfusions, and more. In addition, there is the cost of spraying to attempt to eradicate the mosquitoes that carry the disease. The costs for medication and prevention are quite low compared to the cost of treatment and eradication. The CDC notes, "The average cost for potentially life-saving treatments of malaria are estimated to be U.S.$0.13 for chloroquine, U.S.$0.14 for sulfadoxine-pyrimethamine, and U.S.$2.68 for a 7-day course of quinine" ("Malaria," 2004). Many third-world countries simply do not have the funds to successfully treat or eradicate the disease, and so, their citizens, especially children, continue to die from the disease. This disease is spreading around the world, and each year seems to see more suffering and death due to the disease. The CDC states, "In areas of Africa with high malaria transmission, an estimated 990,000 people died of malaria in 1995 - over 2700 deaths per day, or 2 deaths per minute" ("Malaria," 2004). These numbers are difficult to comprehend, but they show that malaria is one of the deadliest diseases on the planet. The implications are clear. Malaria can live undetected for years, and is a killer, especially of children. It must be controlled and eradicated to keep it from killing even more, and it must be eradicated soon.
The plague is a frightening disease because everyone seems to know the story of the "Black Death" that swept through Europe in the 1300s, killing millions of people. The plague may not be as prevalent today, but because of its' long history, it is probably more frightening to people than many other deadly diseases. The most common form of the plague is the bubonic plague, and it is contracted from the bites of infected fleas that live on infected rats or other rodents. It can also be contracted by direct skin contact of infected tissues, so handling a dead animal with the disease can transmit the disease in some cases, and treating sick patients can also transmit the disease. Unfortunately, the pneumonic form of plague can also be contracted from inhaling droplets from an infected person's cough or sneeze. The CDC notes, "Plague is characterized by periodic disease outbreaks…