This quick reference guide was developed from documents published by the Centers for Disease Control and Prevention as well as the Environmental Protection Agency. For more information, see CDC’s website at http://www.cdc.gov/health/diseases.htm. It is for general information only and not intended to be an authoritative source or to be used as a substitute for consultation with a health care provider.

Key Term:

Pathogen: Disease-producing organism. The identification of microorganisms (e.g., bacteria, viruses, or parasites) pathogenic to humans can be difficult. The presence of coliforms in water is used as an indicator of the possible presence of fecal-derived pathogens.

Key Parasites:

• Giardia lamblia: A one-celled, microscopic parasite that lives in the intestines of people and animals. The parasite is passed in the bowel movement of an infected person or animal. The parasite is protected by an outer shell that allows it to survive outside the body and in the environment for long periods of time. During the past 15 years, Giardia lamblia has become recognized as one of the most common waterborne diseases in humans in the United States. The parasite is found in every region of the United States and throughout the world and commonly found in surface water (lakes, rivers, streams, ditches). Symptoms of Giardia lamblia are diarrhea, abdominal cramps, and nausea. These symptoms typically appear 1 to 2 weeks after infection and can last 4 to 6 weeks. The symptoms can lead to weight loss and dehydration. However, not everyone infected has these symptoms. The parasite is somewhat resistant to chlorine at levels typically found in swimming pools and drinking water. Environmental testing for Giardia is expensive, difficult and usually requires hundreds of gallons of water to be pumped through a filter, therefore, the presence of coliform bacteria or E. Coli may also indicate the presence of Giardia lamblia.



• Cryptosporidium: Cryptosporidium is an important emerging pathogen in the United States and is a cause of severe, life-threatening disease, called Cryptosporidosis, in patients with AIDS and others with impaired immune systems. Both the disease and the parasite are known as “Crypto.” It is manifested as an acute, self-limiting diarrheal illness lasting 7 to 14 days, and it is often accompanied by nausea, abdominal cramps, and low-grade fever. No safe and effective form of specific treatment has been identified to date. Most people with a healthy immune system will recover without medical intervention. People who are in poor health or have a weakened immune system are at higher risk for more severe and more prolonged illness.
  
  The parasite is transmitted by ingestion of oocysts excreted in the feces of infected humans or animals. The infection can result from swallowing just 10 to 100 oocysts – a mouthful of contaminated water. The parasite is resistant to chlorine at levels typically found in swimming pools and public water supplies. Most waterborne outbreaks detected to date have occurred in communities where water utilities met state and federal standards for acceptable quality of drinking water. Crypto has become recognized as one of the most common causes of waterborne disease (drinking and recreational) in humans in the United States.
  
  The parasite was the cause of an outbreak in Milwaukee in 1993 that affected over 400,000 persons. There is considerable circumstantial evidence that low-level (non-epidemic) transmission of Cryptosporidium species through drinking water may be occurring throughout the United States. Recent studies indicate that its oocysts are present in 65% to 97% of surface waters tested.

• Coliforms: All aerobic and facultative anaerobic, gram-negative, non-spore forming, rod- shaped bacteria that ferment lactose with gas formation within 48 hours at 95 F.



• Total coliforms: Non-fecal and fecal coliforms that are detected with a standard test.



• Fecal coliforms: Subgroup of coliform bacteria that has a high correlation with fecal contamination associated with warm-blooded animals. Fecal coliforms are those that grow and produce gas at 112.1 F in 24 hours.



• Enteric bacteria: Bacterial species that normally inhabit the intestinal tract of humans and animals. Included in this group of organisms are some of the most important intestinal pathogens of humans. Most enteric bacteria do not cause disease when confined to the intestinal tract of a healthy host, but given a susceptible host or an opportunity to invade other body sites, many have the capability to produce disease in any tissue.



• Campylobacter: Most people who become ill with Campylobacteriosis get diarrhea, cramping, abdominal pain and fever within 2 to 5 days after exposure to the organism. The diarrhea may be bloody and can be accompanied by nausea and vomiting. The illness typically lasts 1 week. In persons with compromised immune systems, Campylobacter occasionally spreads to the bloodstream and causes a serious life-threatening infection. Campylobacter is one of the most common bacterial causes of diarrheal illness in the United States. Almost all cases occur as an isolated event, not a part of a large outbreak. It is believed most cases go unreported. Campylobacteriosis is estimated to affect over 1 million persons every year, or 0.5% of the general population. Cases are typically associated with handling raw or eating undercooked poultry. One drop of juice from raw chicken meat can infect a person. Larger outbreaks due to Campylobacter are not usually associated with raw poultry but are related to drinking unpasteurized milk or contaminated water. Most illness is caused by the species C. jejuni. Most persons recover completely within 2 to 5 days. In rare cases, some persons develop arthritis, and others develop a rare disease that affects the nerves of the body called Guillain-Barre’ syndrome.



• Escherichia coli. (E. coli): A subset of the coliform group that is part of the normal intestinal flora in humans and animals and is, therefore, a direct indicator of fecal contamination of the water. Most strains are harmless and live in the intestines. However some strains produce a powerful toxin that can cause severe illness.



• E. coli O157:H7: An emerging form of E. coli that produces a powerful toxin that can cause severe illness. An estimated 73,000 cases of infection and 61 deaths occur in the United States each year as a result of infection by this organism. The symptoms are bloody diarrhea and severe abdominal cramps that can last 5 to 10 days. Usually little or no fever is present. In children under 5 years of age and the elderly, the infection can cause a complication called hemolytic uremic syndrome (HUS), in which red blood cells are destroyed and the kidneys fail. About 2% to 7% of infections lead to HUS complications. In the United States, HUS is the principal cause of acute kidney failure in children, and E.coli O157:H7 causes most cases. Most illness has been associated with eating undercooked, contaminated ground beef. Person to person transmission in families and in day care centers is an important mode of transmission. Infection can also occur after drinking raw milk and after swimming in or drinking sewage-contaminated water.



• Leptospira: Leptospirosis is a bacterial disease that affects humans and animals. In humans it causes a wide range of symptoms, and some infected persons may be asymptomatic. Symptoms include high fever, severe headache, chills, muscle aches, and vomiting. More severe cases can result in jaundice and abdominal pain. If not treated, the patient could develop kidney damage, meningitis, liver failure, and respiratory distress. In rare case death occurs. Outbreaks are usually caused by exposure to water contaminated with the urine of infected animals. Many animals such as cattle, pigs, horses, dogs, rodents, and wild animals carry the bacterium. Humans become infected through contact with water, food or soil containing urine of infected animals. The disease is not known to spread from person to person.



• Salmonella: Most persons with Salmonellosis develop diarrhea, fever, and abdominal cramps 12 to 72 hours after infection. The illness usually lasts 4 to 7 days, and most persons recover without treatment. A number of persons infected with Salmonella will develop pain in their joints, irritation of the eyes, and painful urination. This is called Reiter’s syndrome. Reiter’s syndrome can last for months or years and can lead to chronic arthritis. The elderly, infants, and persons with impaired immune systems are at higher risk to develop more severe illness if the infection spreads from the intestines to the blood stream. This can be a life-threatening condition, if not treated with antibiotics promptly. About 600 persons die each year with acute Salmonellosis. Salmonella live in the intestines of humans and animals. Salmonella are usually transmitted to humans by eating food or drinking water that is contaminated with feces. Approximately 40,000 cases of Salmonellosis are reported each year in the United States. Because milder cases are not diagnosed or reported, the actual number of infections may be thirty times or more higher.



• Shigella: A group of bacteria that cause Shigellosis. Most who are infected with Shigella develop diarrhea, fever, and stomach cramps starting a day or two after they are exposed to the bacterium. The diarrhea is often bloody. In some persons, especially young children and the elderly, the diarrhea can be so severe that the patient needs to be hospitalized. A severe infection with high fever may also be associated with seizures in children less than 2 years old. Most persons will recover completely, although about 3% of the population may develop pains in their joints, irritation of the eyes, and painful urination. This called Reiter’s syndrome. These conditions may last years, and lead to chronic arthritis. Some persons who are infected may have no symptoms at all, but may still pass the Shigella bacterium to others. Most Shigella bacteria pass from one infected person to the next via the fecal- oral route. It may also be spread by eating contaminated food or by drinking or swimming in contaminated water.



• Vibrio cholerae: Cholera is an acute, diarrheal illness caused by infection of the intestines with this bacterium. A person can become infected by drinking water or eating food contaminated with the cholera bacterium. The infection can be mild or without symptoms, but sometimes it can be severe. Approximately one in 20 infected persons have severe disease characterized by profuse, watery diarrhea, vomiting, and leg cramps. These persons experience rapid loss of body fluids, which leads to dehydration and shock. Without treatment, death can occur within hours. Cholera has been very rare in industrialized nations for the last 100 years due to advanced water and waste treatment systems. However, because of improved transportation, more persons from the United States travel to areas where epidemic cholera is occurring and increases the risk for exposure.

• Hepatitis A: A virus that causes jaundice, abdominal pain, loss of appetite, intermittent nausea and diarrhea. The disease varies in severity from a mild illness lasting 1-2 weeks, to a severely disabling disease lasting for months. In general the severity of the disease increases with age, with mortality rates of 1.8% for adults over 50 years. Persons with chronic liver disease have an increased risk of death from Hepatitis A infection. It is primarily transmitted by food or fecally contaminated water. 33% of Americans have evidence of past infection (immunity). A highly effective vaccine is available.



• Hepatitis E: A virus that can result in abdominal pain, anorexia, dark urine, fever, hepatomegaly, jaundice, malaise, nausea, and vomiting. The severity of illness increases with age and the overall case-fatality rate is 1% to 3%. The case-fatality rate increases to 15% to 25% in pregnant women. The symptoms appear after an incubation period that averages 40 days. No vaccine is available. Most outbreaks are associated with fecally contaminated drinking water and appear to have little person-to-person transmission. The majority of United States cases have a history of travel to HEV-endemic areas (Mexico, Asia, and parts of Africa).



• Adenoviruses: A virus that commonly causes respiratory illness that may also cause gastroenteritis, conjunctivitis, cystitis, and rash illness. Symptoms of respiratory illness range from the common cold syndrome to pneumonia, croup, and bronchitis. Patients with compromised immune systems are especially susceptible to severe complications. Adenoviruses are unusually stable to chemical and physical agents and adverse pH conditions, allowing for prolonged survival outside the body. They are transmitted by direct contact fecal-oral transmission and occasionally waterborne transmission. Outbreaks of adenovirus-associated respiratory disease have been more common in the late winter, spring, and early summer. However, they can occur throughout the year.



• Norovirus: Noroviruses are a group of viruses that cause the “stomach flu” or gastroenteritis. It is an emerging virus first found in fecal specimens collected during an outbreak of gastroenteritis at an elementary school in Norwalk, Ohio. Each year, approximately 267,000,000 episodes of diarrhea leading to 612,000 hospitalizations and 3,000 deaths occur in the United States. An etiologic agent is identified in <10% of these cases. The symptoms of norovirus usually include nausea, vomiting, diarrhea, and stomach cramping. The illness often begins suddenly, and the infected person feels very sick. The symptoms usually last for about 2 days. Most cases do not have any long- term health affects as the result of the infection, although high-risk populations (children, elderly and those with impaired immune systems) can become dehydrated and may require medical attention. Norovirses are highly contagious and spread rapidly from person to person. The infectious dose appears to be very low (<10 viral particles) and is environmentally stable. Fecal-oral spread is probably the primary transmission mode, although airborne and fomite transmission might facilitate spread in an outbreak. The primary cases in an outbreak result from exposure to fecally contaminated water or food. The secondary and tertiary cases among contacts result from person to person transmission. Of the 348 outbreaks reported to CDC (January 1996 – November 2000), food was implicated in 39%, person- to- person contact in 12%, and water in 3%; 18% could not be linked to a specific transmission mode. There is some evidence that air transmission of the virus can occur, especially in close living quarters like nursing homes, day care centers, and cruise ships. Of the 348 outbreaks reported to CDC during January 1996 – November 2000, a total of 39% occurred in restaurants; 29% occurred in nursing homes and hospitals; 12% in schools and day care centers; 10% in vacation settings, including cruise ships; and 9% in other settings. A person can remain contagious for as long as two weeks after recovery. A person may become infected with norovirus throughout a lifetime, as recovery from infection does not appear to develop into long-lasting immunity. There is currently no antiviral medication that works against norovirus and there is no vaccine to prevent infection.



• Rotavirus: The most common cause of severe diarrhea among children, resulting in the hospitalization of approximately 55,000 children each year in the United States and the death of over 600,000 children annually worldwide. The symptoms of the disease are vomiting and watery diarrhea for 3 to 8 days. These symptoms develop after an incubation period of 2 days. Immunity after infections is incomplete, but repeat infections tend to be less severe than the original infection.
  
  The primary mode of transmission is fecal-oral. Because the virus is stable in the environment, transmission can occur through ingestion of contaminated water or food or contact with contaminated surfaces. In the United States, the disease has a winter seasonal pattern, with annual epidemics occurring from November to April. The highest rates of illness occur among infants and young children, and most children in the United States are infected by 2 years of age. For persons with healthy immune systems, rotavirus gastroenteritis is a self-limited illness.

If we can be of any assistance in controlling unauthorized swimming, please call us at 221-2270.

Back