Waterborne disease

Waterborne or water related diseases encompass illnesses resulting from both direct and indirect exposure to water, whether by consumption or by skin exposure during bathing or recreational water use.

It includes disease due to water-associated pathogens and toxic substances. These diseases are directly related to environmental deterioration and pollution. Despite the continued efforts to maintain water safety, waterborne outbreaks are still reported globally.

Many waterborne pathogens can also be acquired by consuming contaminated food or beverages, from contact with animals or their environment, or through person-to-person spread.

Cholera and typhoid fever are classical examples of waterborne diseases, where only a few highly infectious pathogens are needed to cause severe diarrhea. Shigellosis, hepatitis A, amoebic dysentery and other gastrointestinal diseases can also be waterborne.

Fecal contamination of water is globally recognized as one of the leading causes of waterborne diseases.

While diarrhea and vomiting are the most commonly reported symptoms of waterborne illness, other symptoms can include skin, ear, respiratory, or eye problems.

Diarrhea occurs worldwide and causes 4% of all deaths and 5% of health loss due to disability. Diarrhea is the passing of loose or liquid stools more frequently than is normal for the individual. It is primarily a symptom of gastrointestinal infection. Depending on the type of infection, the diarrhea may be watery (for example in cholera) or passed with blood (in dysentery for example).

Disease which are often water-borne:
*Cholera
*Typhoid
*Infectious hepatitis
*Giardiasis
*Amoebiasis
*Dracunculiasis
Waterborne disease

Foodborne Disease

Foodborne disease continues to be a common and serious threat to public health all over the world and is a major cause of morbidity.

Both industrialized and developing countries suffer large numbers of illness and the incidence on a global basis, appears to be increasing.

Most foodborne illnesses are mild, and are associated with acute gastrointestinal symptoms such as diarrhea and vomiting.

Sometimes food borne disease is much more serious and is life threatening, particularly in children in developing countries and infection can also be followed by chronic sequelae or disability.

In many countries where information on foodborne disease is collected, the total number of cases has been increasing over the past 20-30 years.

Some of the increase recorded are undoubtedly due to improved systems for information collection and reporting, better diagnosis and a greater awareness of food safety, but these changes do not explain the general increase observed.

In recent years, the increased awareness of food safety, changes in regulatory and educational measures and changes in practice in food production have led to decreases in incidence of particular foodborne diseases in some regions.
Foodborne Disease

Foodborne Disease Definition

Foodborne Disease Definition
A foodborne disease is considered to be any illness associated with or in which the causative agent is obtained by the ingestion of food.

Approximately 66% of all foodborne illness outbreaks are caused by bacterial pathogens.

Of the 200 foodborne outbreaks reported each year, approximately 66% are of undetermined etiology.

Unidentified causes may be from the Salmonella and Campylobacter species, Staphylococcus aureus, Clostridium perfringes, Clostridium botulinum, Listeria monocytogenes, Escherichia coli 0157, Shigella, Vibrio and Yersinia enterolitica, which are transmitted through foods.

A wide variety of home cooked and commercially prepared foods have been implicated in outbreaks, but they are most frequently related to foods of animals origin, such as poultry, eggs, red meat, seafood and dairy products.
Foodborne Disease Definition

Calicivirus or Norwalk-like Virus

Calicivirus or Norwalk-like Virus
Diagnosis

• Diarrhea occurring in an outbreak especially in a closed environment
• Tends to infect older children and adults rather than infants
• Nausea and vomiting are common; bloody stools are rare
• Incubation period 1 – 2 days; illness: 1- 4 days
  

Epidemiology
Even in developed countries, antibodies to calicivirus are nearly universal by age 5. Infections tend to occur in family or community outbreaks. In undeveloped countries, infection by these viruses occurs presumably as a result of poor sanitation. In developed countries, outbreaks that occur year round have been describe in school, resorts, hospital , nursing homes, restaurants and cruise ships.

The primary method of spread is fecal-oral but contaminated water or shell fish has accounted for common source of outbreak. A measure of the importance of these agents is that – 10% of all gastroenteritis outbreaks and up to 90 – 95% of those that are non-bacterial are attributed to them. In contrast to infants, who are more often infected by rotavirus, calicivirus cause disease primarily in older children and adults. Immunity is probably short lived at best, suggesting that humoral antibody is not adequately protective. The incubation period is 1 – 2 days, and shedding can persist for 1- 2 weeks.

The Norwalk agent and related viruses are classified as caliciviruses, although they are also similar in appearance to parvoviruses and hepatitis A virus. Among the other human enteric caliciviruses which are named for where these strains were first detected. The human enteric calicivirus are now divided into two genera, provisionally named “Norwalk like virus” and “Sapporo like virus”.

Symptoms
Although calicilike viruses are typically associated with diarrheal illness, nausea and vomiting may occur frequently, especially in children. Bloody stools do not occur. Fever may be present in up to one third of patients. The incubations period in 24 – 48 hrs and the illness lasts 1 – 4 days.
Calicivirus or Norwalk-like Virus

Food Infections: Salmonellosis

Food Infections: Salmonellosis
Food infections are those in which the disease organism is carried through foods to the host (human or animal) where it actually invades the tissues and grows to numbers that cause disease.

Salmonellosis is caused when foods contaminated with Salmonella bacteria are eaten. At the present time, approximately 42,000 cases of salmonellosis are reported yearly. About 150- deaths annually are due to this disease. However, it is considered that only about 1% of acute digestive illnesses are reported in United States, so that actually there may be many more cases of this disease.

Typhoid fever, of which there are fewer cases than of salmonellosis, hence fewer deaths, is caused by an organism belonging to the Salmonella species, but this disease is usually not considered to be the ordinary salmonellosis for three reason:

• The ordinary Salmonella organisms will infect other animals as well as humans, while typhoid germ is known to infect only humans

• Typhoid fever is usually more severe than the ordinary salmonellosis

• In healthy adults, several hundred thousand to several million ordinary Salmonella bacteria (cells) must be ingested (eaten) to cause salmonellosis, while the ingestion of even one typhoid cell may cause typhoid fever.

It is known that antibiotics, especially cholramphenicol or some of the modified penicillin, are effective in treating salmonellosis, but since this disease is oftentimes not called to the attention of a physician, it may cause a more severe illness than if it were treated.
Food Infections: Salmonellosis

Amebiasis

Amebiasis
Amebiasis, as trichinosis, is not a bacterial disease. A single-celled animal (an ameba) cause amebic dysentery in humans. The organism is called Endamoeba histolytica.

Amebiasis varies greatly in symptoms from patients to patient and periodically in severity in the same patient. Diarrhea is a common symptom of the diseases, and it may be persistent and severe, mild and occasional. Abdominal pain, fatigue and fever are sometimes encountered. Incubation lasts from 2 days to several months, but it usually 3-4 weeks.

The control of Amebiasis is essentially matter of good sanitary procedures.

1. Drinking water, water added to foods, and used for washing and sanitizing of equipment and utensils and for irrigation of crops should be portable.
2. Drinking water to be used for foods or for equipment or utensils that contact foods, taken form deep wells, lakes, or ponds, should be tested periodically for bacteriological safety. Although this is not a bacterial disease, it appears to occur when bacteria indicative of pollution with human discharge are present.
   
3. Persons known to have had amebic dysentery should be rigidly excluded from food handling of any kind.

Amebiasis

Ignorance of food handling procedures contribute to foodborne diseases

Ignorance of food handling procedures contribute to foodborne diseases
Almost all the factors that contribute to food disease result from ignorance of proper food-handling procedures or from the unwillingness of some individuals in food industries (including food processor) to comply with the basic guidelines for proper food handling. Thus foodborne diseases will continue to occur at unnecessarily high rates as long as:

• Food handlers do not employ strict sanitation in both their personal habits and in the maintenance of their work area and equipment
• Foods are not properly refrigerated
• Foods are not adequately processed
• Cross contamination situations are not avoided
• Management does not realize the importance of preventing foodborne disease

Proper food handling procedures include rather simple techniques, such as holding at specified temperatures, but they also include complex procedures, such as those for calculating processing times and predicting certain biochemical reactions that might result from processing modifications.

Ordinarily, therefore, at some level in the food processing stage, the services of a professional food technologist are required. Once a food has been properly processed, the remaining handling it undergoes does not require a professional food technologist, but it does require periodic quality control checks by personnel qualified in microbiology and sanitation.
Ignorance of food handling procedures contribute to foodborne diseases

Listeria monocytogenes

Listeria monocytogenes
Listeria monocytogenes -- This organism can cause encephalitis, meningitis, blood-borne infection and death. It is especially hazardous for pregnant women (posing a threat of miscarriage or stillbirth), newborn babies, the elderly and immune-deficient patients. It causes about 28%of deaths due to food poisoning.

Listeria can survive acid, nitrite and salt and can thrive even in the refrigerator, is most commonly found in raw (unpasteurized) milk, soft-ripened cheeses like Brie and ready-to-eat meats like hot dogs and pâté. Other sources of listeria include raw and smoked fish, raw meats and poultry, cooked poultry, fresh vegetables and ice cream.

Listeriosis (listeria infection) starts insidiously, with headache, low-grade fever, muscle aches, nausea and vomiting and is often mistaken for a viral illness that will cure itself. Those factors cause treatment delays and allow the disease to progress. Symptoms can appear anywhere from 3 to 70 days after exposure.

Listeria infections must be treated with injectable antibiotics -- penicillin, ampicillin or gentamicin -- or intravenous trimethoprim/sulfamethoxazole. Prevention is the best defense. Those at greatest risk should avoid foods that are most likely to harbor listeria or they should cook those foods until piping hot (180 degrees) before tasting them.
Listeria monocytogenes