Botulism: definition and classification

Botulism (from Latin botulus, botulism food poisoning "sausage") is a rare but serious paralytic illness caused by a nerve toxin, botulin, that is produced by the bacterium Clostridium botulinum. Botulin is the most potent known toxin, blocking nerve function and leading to respiratory and musculoskeletal paralysis.

There are three main kinds of botulism:

Foodborne botulism is a form of foodborne illness and is caused by eating foods that contain the botulism toxin.

Wound botulism is caused by toxin produced botulism disease from a wound infected with Clostridium dogs botulism botulinum.

Infant botulism is caused by consuming the spores of the botulinum bacteria, which then grow in botulism matambre botulism outbreak from garlic in oil the intestines and release toxin.

All forms of botulism can be fatal and are considered medical emergencies. Foodborne botulism can be especially dangerous as a public health problem because many people can be poisoned from a single contaminated food source.

In the United States an average of 110 food-borne botulism cases of botulism are reported each year. Of these, approximately 25% are foodborne, 72% are infant botulism, and the rest are wound botulism.

Outbreaks of foodborne botulism involving two or more persons occur during most years and moldy bread botulism usually are caused by eating contaminated home-canned foods. The number of cases of foodborne and infant botulism preparation of botulism toxin has changed little in recent years, but botulism + case report form wound botulism has increased because of the use of black-tar heroin, especially in California.
Botulism: definition and classification

Campylobacteriosis

Campylobacteriosis is an acute infectious diarrheal disease caused by the bacterium Campylobacter, a bacterium mostly common found in raw or undercooked poultry meat, unpasteurised milk, and untreated water, is pathogen that cause gastro-enteritis.

Various virulence factors such as flagelin, lipopolysacharides, adhesions and invasions have been implicated in the pathogenesis of Campylobacter infection.The illness normally occurs 2 to 5 days after ingesting the contaminated food.

The illness usually lasts1 week; however some infected individuals may remain asymptomatic.

The illness is estimated too cause approximately 2.4 million cases per year, which is more than shigella and Salmonella bacteria combined. Anyone can contract campylobacteriosis but children under 5 years of age and young adults aged 15 to 29 years are most often afflicted.
Campylobacteriosis

Foodborne gastroenteritis

Intake or handling of contaminated food and water may cause foodborne gastroenteritis. Gastroenteritis is the severe inflammation of the gastrointestinal tract, resulting in acute diarrhea and vomiting.

Acute gastroenteritis is one of the most common illnesses affecting man and may be caused by a large variety of different microbes.

The condition affects mainly children and the elderly, but increasingly also adults of all ages, often following foreign travel or the ingestion of contaminated food and water.

There are agents, many of which cause acute gastroenteritis, that are recognized as known or possible causes of foodborne illness, but for which there were insufficient data to make reliable estimates of incidence. This category includes infectious agents such as Aeromonas spp., Edwardsiella spp., and Plesiomonas spp., and non-infectious agents such as mushroom and marine biotoxins, metals and other inorganic toxins.

In Africa, Asia and Latin America, there are about 1000 million cases of gastroenteritis per year in children under the age of 5, which leads to 5 million deaths. In Mexico and Thailand, half of the children aged 0-4 years suffer from the Campylobacter-induced enteritis.
Foodborne gastroenteritis

Foodborne illness of Campylobacteriosis

According to CDC Campylobacter jejuni is the most common bacterial cause of diarrhea.

Campylobacteriosis is term referring to the infectious disease caused by bacteria of the genus Campylobacter.

Campylobacteriosis is the leading cause of diarrhea in the developed world, with the number of cases exceeding those of salmonellosis and shigellosis.

Campylobacteriosis is considered a zoonosis, a disease that can be passed from animals to humans under natural conditions. Among animals, the most common form of transmission is via the fecal-oral-route.

An estimated 2 million to 4 million cases occur each year in the United States, according to population based studies.

Campylobacter jejuni, the bacterial agent responsible for the illness, is a gram negative, slender, curved rod.

Symptoms of Campylobacteriosis usually occur within two to 10 days of ingesting the bacteria. Children, the elderly and people with weakened immune systems are particularly at risk.

The most common symptoms include mild to severe diarrhea, fever, nausea, vomiting and abdominal pain.
Foodborne illness of Campylobacteriosis

Food irradiation reduces biological food contamination

Food irradiation reduces biological food contamination and related foodborne illness.

With the increase of some food borne infectious diseases in many countries, irradiation has been proposed as a procedure which could eliminate microbial pathogen contamination of food at the processor level and thus allow the delivery to the consumer of a safer product.

Food irradiation has been approved for use in the United States in selected foods since 1963. 

Electromagnetic radiation suitable for food irradiation may be electrons, X-rays or gamma ray. Ionizing radiation passes through the food and destroys harmful bacteria and other organisms.

Irradiation could reduce spoilage ro the need for fungicides for fruits, and increase the safety of meats.

It is also effective for seafood, eggs, precooked meats and produce. It is safe, proven process that has many useful applications.

The potential for using radiation as a way of destroying pathogens in food has been known for more than a century.
Food irradiation reduces biological food contamination

Foodborne Disease Incidence

Accurate estimates of the yearly incidence of foodborne disease are difficult and sometimes impossible, depending on the reporting systems in different countries.

Many countries have no system for collecting and reporting data on gastrointestinal infections and even where these exists the reported data is acknowledged to represent only a fraction of the true number of cases.

The true incidence of food borne infection is also difficult to determine since asymptomatic infection is common, because only a minority of people will seek medical treatment and because only a minority of patients will be investigated microbiologically.

Food borne disease statistics in some European countries and the Americas, where reporting systems are netter than some other regions, are dominated by cases of salmonellosis and campylobacteriosis.

While in other regions, however, foodborne disease statistics tend to rely on outbreak information only, and in some cases, other organism, are identified as leading causes of illness.

For example in Australia, of the 17,2 million cases of gastroenteritis each year in Australia, there are 5.4 million cases that are conservatively estimated to be due to contaminated food resulting in the loss of 6.5 million days of paid work.

In the US, it has been estimated that foodborne disease cause approximately 78 millions illnesses, 325,000 hospitalization and 5000 deaths each year, with known pathogens accounting for 14 millions illness, 60,000 hospitalizations and 1800 deaths.

The organism identified as causing the largest number of foodborne related cases of illness were Norwalk-like virus, followed by campylobacter, salmonellas, Clostridium perfringes, Giardia lamblia, staphylococci, Escherichia coli, and Toxoplasma gondii, respectively.

A number of well publicized outbreaks of food borne illness and recalls of meat and meat products have occurred during the past decade.

Many million of kilograms of ground beef and luncheon meat have been recalled because of potential contamination with E. coli o157:H7 and Listeria monocytogenes, respectively.

A large outbreak in the early 1990s due to E. coli O157:H7 contaminated hamburgers resulted in four deaths and hundred of illnesses.
Foodborne Disease Incidence

Foodborne Illness

Foodborne Illness
Foodborne illness may follow ingestion of foods contaminated with bacteria, algae, protozoa, parasites and other organism, as the result of food sensitives or chemical or drug contamination.

Foodborne illness is an important cause of acute morbidity and increased short term mortality.

Approximately 600 outbreaks of foodborne illness are reported to the CDC every year.

In addition, infections with Salmonella, Campylobacter and Yersinia enterocolitica are associated with increased long term mortality.

When faced with the symptoms of acute gastrointestinal illness, structural, functional and metabolic causes must also be considered.

Because incubation periods of foodborne illness may quite long, with many meals and other activities occurring in the interim, the association between contaminated food intake may not be made or may be erroneous.

Evaluating the differential diagnosis and initiating treatment before a definitive diagnosis is available are significant clinical challenges.

Bacterial organisms are the most common cause of foodborne illness and may be result of other direct action of the organism or the action of endo or exotoxins.

The incubation period depends on whether there is a preformed exotoxin, which generally produces symptoms sooner than illness that results from organisms that must first reproduce and elaborate a toxin in the gastrointestinal tract.

Salmonella was the most commonly reported foodborne poisoning reported to the CDC. Other common bacterial causes included Escherichia coli, Clostridium perfringes, Shigella, Staphylococcus aureus, Bacillus cereus, Complybactor species, Streptococcus, listeria monocytogenes, Clostridium botulinum, Vibrio parahaemolyticus and Y. enterolitica.

Marine agents and toxins may produce similar symptoms. Common parasitic causes of diarrhea include Guardia, Cryptosporidium and Entamoeba histolytica.

Rotavirus is the most common cause of acute diarrhea among children, accounting for one fourth of all cases, but many virus can cause diarrhea as well, including Norwalk like virus, enteric adeno-viruses, astroviruses and calciviruses.
Foodborne Illness

Risks Associated With Seafood

Risks Associated With Seafood
The safety of seafood in the US has increased in recent decades, although there are still a number of chemical and microbial hazards that are present in seafood.

Whether a contaminant poses a health risk to consumers depends on the amount present in the food and the potential outcome from exposure.

Consumers are exposed to a complex mixture of dietary and non-dietary contaminants.

However, most studies of the risks associated with seafood focus on one contaminant at a time rather than a mixture.

The extent to which such co-exposure might affect the toxicity of seafood-borne contaminants is largely unknown.

Similarly, few data are available on the extent to which beneficial components of seafood, such as selenium, might mitigate the risks associate with seafood-borne contaminants.

The evidence reviewed indicates that the levels of different contaminants in seafood depend on several factors such as species, size, location, age and feed source.

Levels of some contaminants in seafood vary substantially due to their geographic localization; areas of highest variation tend to be mostly fresh-water.

Consumption of aquatic foods is the major route of human exposure to methyl-mercury. The seafood choices a consumer makes and the frequency with which different species are consumed are thus important determinants of methyl-mercury intake.

Exposure to MeHg among US consumers in general is a concern because there is uncertainty about the potential for subtle adverse health outcomes.

Persistent organic pollutant (POPs), including dioxins and PCBs, can be found in the fatty tissue of all animal derived foods, including seafood.

The greatest concern is for population groups exposed to POPs is seafood obtained through cultural subsistence, or recreational fishing, because of reliance on fish from location that may pose a greater risk.

In contrast to heavy metal contaminants and POPs, the number of reported illness from seafood-borne microbial contaminants has remained steady over the past several decades.

Exposure to vibrio ad norovirus infection is still, a concern, however, because they continue to be associated with consumption of raw molluscan shellfish.

Strategies for minimizing the risk of seafood-borne illness are, to some extent, hazard-specific, but overall include avoiding types of seafood identified as being more likely to contain certain contaminants, and following general food safety guidelines, which include proper cooking.
Risks Associated With Seafood

Foodborne Disease Caused by Micro-organisms

Foodborne Disease Caused by Micro-organisms
Foodborne disease is a public health problem which comprises a broad group of illnesses.

Among them, gastroenteritis is the most frequent clinical syndrome which can be attributed to a wide range of micro-organisms, including bacteria viruses and parasites.

Usually, the incubation period is short, from 1-2 days to 7 days.

Different degrees in severity are observed, for a mild disease which does not require medical treatment at the more serious illness requiring hospitalization, long term disability and /or death.

The outcome of exposure to foodborne diarrheal pathogens depends on a number of host factors including preexisting immunity, the ability to elicit an immune response, nutrition, age, and non specific host factors.

As a result, the incidence the severity and the lethality of foodborne diarrhea is much higher in some particularly vulnerable segments of the population, including children under five years of age, pregnant women, immuno-compromised people and elderly.

In addition to these well known predisposing conditions, new ones are regularly identified (liver disease for paraheamoliticus septicemia, thalassemia for Yersinia enterocolitica infections).

Serious complications may result from these illnesses including intestinal as well as systemic manifestations, like hemolytic uremic syndrome for 10% of Escherichia coli 0157:H7 infections with bloody diarrhea, Guillain-Barre syndrome (nerve degeneration, slow recovery and severe residual disability) after Campylobacter jejuni infection, reactive arthritis after salmonellosis and chronic toxoplasmic encephalitis.

While diarrhea is the most common syndrome following the consumption of a contaminated food some disease are more serious.

Clinical manifestations of listeriosis include bacteriemia and central nervous system infections, especially in patients with an impairment of T-cell mediated immunity and abortion in pregnant women, with an overall case fatality rate of 25%.

Food borne botulism is a result from the potent toxin by Clostridium botulinum that cause a paralysis of skeletal and respiratory muscles which, when severe may result in death in 8% of cases.

Toxoplasma gondii is also the most frequent cause of lesion in the central nervous system in patients with AIDS.

Hepatitis A is an infectious disease for which age is the most important determinant of morbidity and mortality, with severity of illness and its complications increasing with age.

The durations of illness vary but most cases are symptomatic for three weeks.

Complications during the acute illness phase are unusual, with fulminant hepatitis and death being uncommon.
Foodborne Disease Caused by Micro-organisms

Bacteria in General

Bacteria in General
Bacteria are single celled organisms that can cause foodborne illness in two ways

1. They can infect foods themselves, by their presence in the food as they feed on it
2. They can produced toxins, which can make food hazardous, as they breakdown. Bacteria, under good condition, can grow and divide quickly – each cell dividing into two approximately every 20 minutes.
   

Good conditions for bacterial growth require

• Food – especially high protein

• Acidity – neutral to low acid

• Temperatures –especially 40 – 140 degree F, ideal temperature is 90 to 100 degree F about body temperature

• Oxygen

• Moisture

When one or more of these six factor is present in a food product, creating the conditions for bacterial growth, that food product is a potentially hazardous food. Potential hazardous foods therefore include meats; poultry; fish; soy-based foods; eggs; milk and milk products; cooked pasta, rice, potatoes, or beans; garlic oil mixture; raw fruits and vegetables; and raw seeds and sprouts. Some of these items surprise many people – it’s not the mayonnaise that is the problem on a buffet; rather, it is the moisture content and low acidity of the items that are put into mayonnaise – potatoes, pasta, beans, etc. Some bacteria even produce spores that don’t reproduce but can survive heating and cooling so that as conditions improve the spore’s bacteria can become active again.
Bacteria in General

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

Salmonella: significance as a pathogen

Salmonella: significance as a pathogen
Two clinical entities cause by Salmonella are recognized: enteric fever (a severe, life threatening illness) and the more common food poisoning syndrome. In both cases, the organisms enter the body via oral route.

Enteric fever, commonly referred to as typhoid fever, is primarily caused by the one species Salmonella typhi, but other salmonella are potentially capable of producing this syndrome. The symptoms of enteric fever are generally not elicited through the intestinal tract, although the route of entry into the body is primarily oral. However, a short period of vomiting and diarrhea sometimes occurs in the first day or two in typhoid fever. The onset times vary considerably between typhoid and paratyphoid enteric fevers. Onset times for typhoid are usually 8 – 15 days, seldom as short as 30 – 35 days: while onset time for paratyphoid fever tends to be shorter, and may be so short as to suggest food poisoning. The usual symptoms of salmonellosis are headache, malaise, anorexia, and congestion of the mucous membranes, especially of the upper respiratory tract. Bacteremia generally occurs on the first week of illness.

The food poisoning syndrome is characterized by a self-limiting acute gastroenteritis. Contaminated food or water is the usual, but not the only, vehicle. The incubation period varies from 6 to 48 hours and generally falls within a range of 12 – 36 hrs. Variation in the incubation time may be attributed to the size of the infecting dose, the virulence (degree of pathogenicity) of the organisms, the susceptibility of the host, and the physicochemical composition of the transmitting food. Symptoms include diarrhea, abdominal cramps, vomiting and fever which generally last from 1 - 7 days. However, the organisms may be excreted in the feces for many weeks after symptoms subside.

Salmonellosis may be confused clinically with staphylococcal intoxications, but there are important distinctions. Salmonella has a longer incubation period than staphylococci and is usually accompanied by fever, which is absent in staphylococcal intoxication. And, unlike Salmonella food poisoning, the acute symptoms of staphylococcal food poisoning normally disappear within 24 hrs.

In some case, the gastroenteritis may be followed by extraintestinal invasion resulting in enteric fever, which is more, likely to occur in the very young, the aged and debilitated patients.
Salmonella: significance as a pathogen

Salmonellosis: Illness cause by Salmonella

Salmonellosis is an illness caused by Salmonella bacteria. An infection with these bacteria usually affects the gastrointestinal system (the stomach and intestines) in humans. In more severe cases, Salmonella can spread to the blood, the bones, or even to the fluid around the brain, but these types of infection are less common.

An American scientist named Daniel E. Salmon is credited with the discovery of the Salmonella family of bacteria in the late 1800s.

Though named for him, it turns out that Salmon was not the true discoverer of Salmonella - a researcher working under him named Theobald Smith actually deserves the credit. Since then, scientists have identified more than 2,400 types of Salmonella bacteria.

Scientists have also figured out where Salmonella live, how they spread to humans, and how to reduce their spread among the general public. Even so, each year about 40,000 cases of salmonellosis are reported in the United States, although many more cases go unreported.

Salmonella bacteria are often found in the feces (poop) of some animals, particularly reptiles. Iguanas, for example, are known to carry Salmonella marina. People who have these animals as pets have a greater risk of contracting salmonellosis because the feces can contaminate a reptile's skin. Then, when people handle the reptiles, they get the bacteria on their hands. As with all type of Salmonella, the risk of contracting salmonellosis can be reduced with careful attention to hand washing.

Other strains of Salmonella can spread to people in foods contaminated with animal feces. This happens when foods such as poultry, eggs, and beef are not processed according to public health standards. Fruit and vegetables can also become contaminated from feces in the soil where they are grown. The bacteria can also be spread through prepared foods if infected food handlers do not properly wash their hands after using the bathroom.

Young children and infants are more likely to become ill from Salmonella because their developing immune systems have a harder time fighting off the infection. Other people at risk for more serious complications include older people, those with weakened immune systems, and people who take cancer drugs, antacids, or stomach acid suppression medication.

In these higher-risk groups, Salmonella is more likely to invade beyond the gastrointestinal tract and cause bacteremia (bacteria in the bloodstream). From there the bacteria can spread deeper into the body and cause more severe symptoms.
Salmonellosis: Illness cause by Salmonella

Foodborne disease

Foodborne Disease
Illness from foodborne disease has reached epidemic proportions in the United States, even though many cases are mistaken for intestinal flu. Foodborne diarrheal disease may be life-threatening or may have long-term consequences such as autoimmune disorders (including rheumatoid arthritis), cardiovascular disease, and allergies.

It can damage the structure and function of the intestines, leading to malabsorption, and can weaken the body’s immune system. Formerly, most foodborne illness resulted from foods prepared within the home, but now the major portion is caused by foods eaten away from home and by factory-prepared foods.

Changed agricultural practices are part of the problem. Antibiotic use in farm animals is the primary cause of the increase in salmonellosis, now a major foodborne disease. For years, critics warned that the resultant development of antibiotic-resistant bacteria could be followed by animal-to-human transmission. But cattlemen and agricultural officials demanded proof. Proof has now been supplied by several carefully conducted studies tracing human salmonellosis back to resistant bacteria in meat.

Current food trends contribute to foodborne disease – fads such as steak tartare, marinated raw beef, undercooked goose liver, rare duck breasts, and, especially, undercooked or raw fish; the incidence of infections from the latter two is increasing in the United States. All of these present serious health problems. Fish tapeworm infections have not been associated with properly canned commercial fish, but the larval parasite can survive up to 400 days in iced fish.

To kill the tapeworms, one must either cook all finfish thoroughly, with all parts reaching 145° F for at least five minutes; or freeze it at -4° F for 72 hours; or brine the fish for at least three weeks; or smoke it and then cook it at 150 to 180° F ("hot smoking"). Commercial smoked salmon (lox) is judged safe, but gravlax and belly lox are potentially dangerous. Through cooking of finfish kills roundworms. The internal temperature of the fish must reach 145° F.

The current recommendation is to cook 13 minutes at 450° F for each inch of thickness of fish. This practice offers greater safety than the previous recommendation of 10 minutes. Roundworms are commonly found in cold-water fish such as Pacific Salmon, Atlantic cod, pollack, mackerel, herring, and Atlantic plaice, some of which are being recommended for their omega 3 fatty acids. Roundworms also have been found in commercial gourmet frozen fish dinners, which should be cooked thoroughly.

What is to be done?
*Avoid raw and undercooked flesh foods
*Store foods at safe temperatures
*Cook and reheat foods thoroughly
*Practice good personal hygiene Practice good food sanitation, such as scrubbing of hands, knives, and cutting boards with hot soapy water
*Use an impermeable cutting board for flesh foods and reserve another cutting board for other foods.
Foodborne Disease