Cholera Cholera is caused by a bacterial infection of the intestine. In many cases the infection is mild sometimes producing no symptoms at all. But approximately one in 20 people infected with cholera has a serious case, with symptoms including severe diarrhea, vomiting, and leg cramps. These symptoms quickly cause dehydration and shock, and can result in death within hours if the infected person doesn t receive treatment. Cholera is typically transmitted by contaminated food or water. In areas with poor treatment of sewage and drinking water, the feces of people with cholera can enter the water supply and spread quickly, resulting in an epidemic. The cholera bacterium may also live in the environment in some coastal waters, so shellfish eaten raw can be a source of cholera in affected areas. In the U.S., as in most other industrialized nations, cholera was common in the 1800s but has been virtually wiped out by modern sewage and water treatment systems. Travelers to areas where cholera is endemic may be exposed to the bacterium and can bring it back when they return. The risk of this is very low, however, and can be avoided by taking simple precautions when eating and drinking in areas with epidemic cholera. Also, because the disease isn t likely to spread through casual contact, returning travelers typically don t cause widespread cholera outbreaks. Although some cholera infections can be very severe, and even fatal, the disease can be easily and successfully treated by quickly replacing the fluid and salts lost through diarrhea. With adequate treatment, fewer than 1 percent of cholera patients die from the disease. Ebola Ebola, previously known as Ebola hemorrhagic fever, is a rare and deadly disease caused by infection with one of the Ebola virus species. Ebola can cause disease in humans and nonhuman primates (monkeys, gorillas, and chimpanzees). Symptoms of Ebola include Fever Severe headache Muscle pain Weakness Fatigue Diarrhea Vomiting Abdominal (stomach) pain Unexplained hemorrhage (bleeding or bruising)
Symptoms may appear anywhere from 2 to 21 days after exposure to Ebola, but the average is 8 to 10 days. When an infection occurs in humans, the virus can be spread to others through direct contact (through broken skin or mucous membranes in, for example, the eyes, nose, or mouth) with blood or body fluids (including but not limited to urine, saliva, sweat, feces, vomit, breast milk) of a person who is sick with or has died from Ebola, objects (like needles and syringes) that have been contaminated with body fluids from a person who is sick with Ebola or the body of a person who has died from Ebola, infected fruit bats or primates (apes and monkeys) People get Ebola through direct contact (through broken skin or mucous membranes in, for example, the eyes, nose, or mouth) with blood or body fluids (including but not limited to urine, saliva, sweat, feces, vomit, breast milk, and semen) of a person who is sick with or has died from Ebola, objects (like needles and syringes) that have been contaminated with body fluids from a person who is sick with Ebola or the body of a person who has died from Ebola, and infected fruit bats or primates (apes and monkeys). Food Poisoning Generally, food poisoning causes some combination of nausea, vomiting, and diarrhea that may or may not be bloody, sometimes with other symptoms. After eating tainted food, abdominal cramps, diarrhea, and vomiting, can start as early as one hour in the case of staph and as late as 10 days in the case of campylobacter. It may take even longer to develop symptoms from parasite infections such as Giardia. Symptoms can last from one day up to a couple of months or longer, depending on the type of infection. Vomiting, diarrhea, sweating, dizziness, tearing in the eyes, excessive salivation, mental confusion, and stomach pain may be symptoms of chemical or toxin food poisoning such as that from poisonous mushrooms. Partial loss of speech or vision, muscle weakness, difficulty swallowing, dry mouth, muscle paralysis from the head down through the body, and vomiting may indicate botulism, a severe but very rare type of bacterial food poisoning. Influenza Influenza, more commonly known as the flu, is caused by a contagious virus. Symptoms include body aches, sore throat, headache, fever, coughing, and chills. Perhaps because influenza is so common, misconceptions about the disease abound. Often, people who experience a bad cold say they have the flu, but this is incorrect: Unlike influenza, colds rarely cause headaches or fever. And despite widespread use of the term stomach flu, true influenza does not cause gastrointestinal symptoms. The flu is spread through airborne respiratory secretions. Symptoms can be serious, and the disease can be fatal especially for babies, the elderly, and people with weakened immune systems. When
influenza pandemics occur, they spread quickly, often killing large numbers of previously healthy people. Influenza is still very common in the U.S.: According to the Centers for Disease Control and Prevention, between 5 percent and 20 percent of Americans get the flu every year, and about 36,000 cases are fatal. The disease can be treated by antiviral medicines, and a seasonal vaccine is available to protect against it. Because the virus changes every year, the vaccine must be reformulated yearly. Doctors recommend that high-risk members of the population get a vaccine at the beginning of each flu season. Malaria Malaria is caused by a parasite transmitted by infected mosquitoes. Symptoms occur ten days to four weeks after being bitten and are similar to symptoms brought on by the flu chills, fever, sweating, headache, and muscle pain. In serious cases, malaria may cause vomiting, anemia (iron deficiency), kidney failure, coma, and death. The disease can be prevented by taking anti-malarial drugs and by avoiding mosquito bites in areas where malaria infection is common. Those infected with malaria can be treated with prescription drugs, which are most effective when taken early in the course of the disease. The parasite that most often causes malaria needs warm temperatures to grow and thrive, so the disease is typically found in tropical and subtropical countries. Malaria was once common in most of Europe and North America, but effective mosquito control and other measures have nearly eradicated the disease in these regions. While only about 1300 cases of malaria are reported in the U.S. each year, 300 to 500 million cases occur around the world mostly in developing countries resulting in more than 1 million deaths from malaria globally each year. Measles Measles is a highly contagious disease caused by a virus. Early symptoms include fever, cough, red eyes, and a runny nose. During the first few days, the characteristic measles rash appears, beginning with white spots in the mouth and spreading to a red rash that covers the entire body. The rash typically lasts four to seven days. Severe cases of measles can cause diarrhea, ear infection, pneumonia, encephalitis (swelling of the brain), and death. The measles virus is easily spread through airborne droplets expelled by coughing or sneezing, and can live in the air for up to two hours after an infected person has been present. After exposure, the virus lives in the body for about two weeks before symptoms appear. There is no specific remedy available for measles, so treatment usually consists of bed rest and easing symptoms. Measles are still quite common, with more than 20 million people infected around the world each year. In the U.S., a widespread immunization campaign has successfully controlled the disease, and fewer than 150 cases have been reported since 1997. About half of these cases result from visits to
other countries where measles is still endemic including some developed countries in Europe and Asia. Poliomyelitis Poliomyelitis (often shortened to polio ) is a viral infection spread by person-to-person contact. Symptoms vary according to the type of infection, and three basic patterns are common: Subclinical infections, which account for the vast majority of polio cases. Symptoms may include fatigue, headache, sore throat, mild fever, and vomiting. In some subclinical infections, no symptoms may appear. Nonparalytic poliomyelitis. Symptoms may include back pain, neck pain, fatigue, diarrhea, headache, leg pain, fever, muscle stiffness, painful rash, and vomiting. Paralytic poliomyelitis (the most serious kind of polio infection.) Symptoms may include fever, breathing difficulty, constipation, headache, muscle pain, muscle spasms, and muscle weakness on one side of the body. Muscle weakness comes on quickly and progresses to paralysis. Treatments vary according to the form of the disease, and may include antibiotics, pain-relieving medication, and physical therapy to strengthen weak muscles. In 90 percent of cases a complete recovery is possible. Paralytic cases account for the other 10 percent, which are rarely fatal but typically result in permanent disability. Polio mainly strikes children under the age of 5, and until the 1950s, thousands of children around the world were permanently disabled by polio. In the late 1950s and early 1960s, scientists developed effective vaccines that nearly eradicated polio as a public health problem in industrialized countries. Efforts are underway to eliminate the disease world-wide, but around a dozen countries have reported cases in the last two years. Scarlet Fever Scarlet fever is a disease caused by Streptococcus bacteria the same bacteria that cause strep throat. The bacteria are spread through contact with the oral or nasal fluids of an infected person. Scarlet fever begins with a fever and sore throat, and later causes a red rash that starts at the chest and spreads over the body. Most cases of scarlet fever occur in children under the age of 18, and it was once a very serious childhood disease. Before effective treatments became available it often led to rheumatic fever and death, but the availability of antibiotics has dramatically reduced the scarlet fever mortality rate. Scurvy Scurvy is a disease caused by a vitamin C deficiency. Symptoms of scurvy include weakness, anemia, gum disease, and bleeding from the mucus membranes. The disease was once common among sailors who were at sea for long periods without access to fresh fruit. When it became widely known that citrus fruits (with their abundant vitamin C) could prevent scurvy, sailors began taking
lemon juice on long voyages and incidences of scurvy diminished greatly. Cases of scurvy in the U.S. are now rare, but the disease occasionally appears in older, malnourished adults. Typhoid Fever Typhoid fever is a bacterial infection caused by Salmonella typhi bacteria. At the onset of typhoid fever, symptoms include fever, malaise, and stomach pain. As the disease progresses, the fever increases to over 103 degrees Fahrenheit and diarrhea begins. Eventually weakness and delirium develop, and in some cases a rash appears on the chest and abdomen. Salmonella typhi bacteria are spread by contaminated food or water. The bacteria live in the intestinal tracts of infected humans and can enter the food supply as a result of improper hand-washing. Bacteria may also enter the water supply in places where sewage is improperly treated. Typhoid bacteria can live in the intestines of healthy people who carry and spread the disease without ever experiencing symptoms. In New York in 1906, a cook named Mary Mallon was linked to outbreaks of typhoid fever in every town where she worked. Eventually she was tested, and doctors discovered that although Mallon was perfectly healthy, she unknowingly carried the typhoid bacteria. She became notorious as a disease carrier, acquiring the nickname Typhoid Mary. Because of modern sanitation, cases of typhoid fever in the U.S. and other industrialized nations are now rare, but the disease still occurs regularly in nations where sewage treatment is inadequate. In most cases, typhoid fever is not fatal if it is treated with antibiotics, but if left untreated the disease has a mortality rate of 10-30%. The most effective prevention method is proper hygiene and sanitation, but vaccines against the disease are also available. Yellow Fever Yellow fever is a viral infection transmitted by mosquitoes that carry the virus. The disease typically occurs in tropical areas, particularly in parts of South America and Sub-Saharan Africa. Before its cause was known, yellow fever was also common in the U.S., and outbreaks killed thousands in port cities, including Philadelphia, New York, Baltimore, Norfolk, and New Orleans. In 1900, U.S. Army physicians made the connection between yellow fever and mosquito bites, and subsequent efforts to control mosquitoes led to a significant decline in yellow fever cases in the U.S. The last epidemic of yellow fever occurred in New Orleans in 1905. Yellow fever symptoms usually appear three to six days after being bitten by an infected mosquito, and they develop in three stages. In the first stage, symptoms include fever, headache, muscle aches, vomiting, and jaundice. This lasts for three to four days before the second stage remission begins. During remission, the fever and other symptoms go away. Most people recover at this stage, but some move on to the third stage intoxication. This stage is the most serious, and involves liver and kidney failure, bleeding disorders, delirium, coma, and seizures. Yellow fever that reaches this third stage is often fatal. Although individual symptoms can be treated, no effective treatments exist for the disease itself. A vaccine that effectively prevents yellow fever has been widely available since the 1950s.
Zika Virus Zika virus disease (Zika) is a disease caused by Zika virus that is spread to people primarily through the bite of an infected Aedes species mosquito. The most common symptoms of Zika are fever, rash, joint pain, and conjunctivitis (red eyes). The illness is usually mild with symptoms lasting for several days to a week after being bitten by an infected mosquito. People usually don t get sick enough to go to the hospital, and they very rarely die of Zika. For this reason, many people might not realize they have been infected. Once a person has been infected, he or she is likely to be protected from future infections. Zika virus was first discovered in 1947 and is named after the Zika forest in Uganda. In 1952, the first human cases of Zika were detected and since then, outbreaks of Zika have been reported in tropical Africa, Southeast Asia, and the Pacific Islands. Zika outbreaks have probably occurred in many locations. Before 2007, at least 14 cases of Zika had been documented, although other cases were likely to have occurred and were not reported. Because the symptoms of Zika are similar to those of many other diseases, many cases may not have been recognized. In May 2015, the Pan American Health Organization (PAHO) issued an alert regarding the first confirmed Zika virus infection in Brazil and on Feb 1, 2016, the World Health Organization (WHO) declared Zika virus a public health emergency of international concern (PHEIC). Local transmission has been reported in many other countries and territories. Zika virus likely will continue to spread to new areas.