Diagnosis is made by any blood, bone marrow or stool cultures and with the Widal test (demonstration of antibodies against "Salmonella" antigens O-somatic and H-flagellar). In epidemics and less wealthy countries, after excluding malaria, dysentery, or pneumonia, a therapeutic trial time with chloramphenicol is generally undertaken while awaiting the results of the Widal test and cultures of the blood and stool.

The Widal test is time-consuming, and prone to significant false positive results. The test may be also falsely negative in the early course of illness. However, unlike Typhidot test Widal test quantifies the specimen with titres.

Typhidot is a medical test consisting of a dot ELISA kit that detects IgM and IgG antibodies against the outer membrane protein (OMP) of the Salmonella typhi. The typhidot test becomes positive within 2–3 days of infection and separately identifies IgM and IgG antibodies. The test is based on the presence of specific IgM and IgG antibodies to a specific 50Kd OMP antigen, which is impregnated on nitrocellulose strips. IgM shows recent infection whereas IgG signifies remote infection. The most important limitation of this test is that it is not quantitative and result is only positive or negative.

The term 'enteric fever' is a collective term that refers to severe typhoid and paratyphoid.

Specimen: Fresh stool is collected.

Culture: Specimen is inoculated on selective media like McConkey's agar, DCA, XLD agar. Selenite F broth(0.4%) is used as enrichment medium which permits the rapid growth of enteric pathogens while inhibiting the growth of normal flora like "E. coli" for 6–8 hours. Subculture is done on the solid media from selenite F broth. All the solid media are incubated at 37 degrees for 24 hours.

Cultural characteristics: Colorless (NLF) colonies appear on McConkey's agar which are further confirmed by gram staining, hanging drop preparation and biochemical reactions.

Cultures of stool samples are examined to identify the organism causing dysentery. Usually, several samples must be obtained due to the number of amoebae, which changes daily. Blood tests can be used to measure abnormalities in the levels of essential minerals and salts.

A clinical diagnosis may be made by taking a history and doing a brief examination. Treatment is usually started without or before confirmation by laboratory analysis.

As resistance to ampicillin, chloramphenicol, trimethoprim-sulfamethoxazole, and streptomycin is now common, these agents have not been used as first–line treatment of typhoid fever for almost 20 years. Typhoid resistant to these agents is known as multidrug-resistant typhoid (MDR typhoid).

Ciprofloxacin resistance is an increasing problem, especially in the Indian subcontinent and Southeast Asia. Many centres are shifting from using ciprofloxacin as the first line for treating suspected typhoid originating in South America, India, Pakistan, Bangladesh, Thailand, or Vietnam. For these people, the recommended first-line treatment is ceftriaxone. Also, azithromycin has been suggested to be better at treating typhoid in resistant populations than both fluoroquinolone drugs and ceftriaxone. Azithromycin significantly reduces relapse rates compared with ceftriaxone.

A separate problem exists with laboratory testing for reduced susceptibility to ciprofloxacin: current recommendations are that isolates should be tested simultaneously against ciprofloxacin (CIP) and against nalidixic acid (NAL), and that isolates that are sensitive to both CIP and NAL should be reported as "sensitive to ciprofloxacin", but that isolates testing sensitive to CIP but not to NAL should be reported as "reduced sensitivity to ciprofloxacin". However, an analysis of 271 isolates showed that around 18% of isolates with a reduced susceptibility to ciprofloxacin (MIC 0.125–1.0 mg/l) would not be picked up by this method. How this problem can be solved is not certain, because most laboratories around the world (including the West) are dependent on disk testing and cannot test for MICs.

With colonoscopy it is possible to detect small ulcers of between 3–5mm, but diagnosis may be difficult as the mucous membrane between these areas can look either healthy or inflamed.

Asymptomatic human infections are usually diagnosed by finding cysts shed in the stool. Various flotation or sedimentation procedures have been developed to recover the cysts from fecal matter and stains help to visualize the isolated cysts for microscopic examination. Since cysts are not shed constantly, a minimum of three stools are examined. In symptomatic infections, the motile form (the trophozoite) is often seen in fresh feces. Serological tests exist, and most infected individuals (with symptoms or not) test positive for the presence of antibodies. The levels of antibody are much higher in individuals with liver abscesses. Serology only becomes positive about two weeks after infection. More recent developments include a kit that detects the presence of amoeba proteins in the feces, and another that detects ameba DNA in feces. These tests are not in widespread use due to their expense.

Microscopy is still by far the most widespread method of diagnosis around the world. However it is not as sensitive or accurate in diagnosis as the other tests available. It is important to distinguish the "E. histolytica" cyst from the cysts of nonpathogenic intestinal protozoa such as "Entamoeba coli" by its appearance. "E. histolytica" cysts have a maximum of four nuclei, while the commensal "Entamoeba coli" cyst has up to 8 nuclei. Additionally, in "E. histolytica," the endosome is centrally located in the nucleus, while it is usually off-center in "Entamoeba coli." Finally, chromatoidal bodies in "E. histolytica" cysts are rounded, while they are jagged in "Entamoeba coli". However, other species, "Entamoeba dispar" and "E. moshkovskii", are also commensals and cannot be distinguished from "E. histolytica" under the microscope. As "E. dispar" is much more common than "E. histolytica" in most parts of the world this means that there is a lot of incorrect diagnosis of "E. histolytica" infection taking place. The WHO recommends that infections diagnosed by microscopy alone should not be treated if they are asymptomatic and there is no other reason to suspect that the infection is actually "E. histolytica". Detection of cysts or trophozoites stools under microscope may require examination of several samples over several days to determine if they are present, because cysts are shed intermittently and may not show up in every sample.

Typically, the organism can no longer be found in the feces once the disease goes extra-intestinal. Serological tests are useful in detecting infection by "E. histolytica" if the organism goes extra-intestinal and in excluding the organism from the diagnosis of other disorders. An Ova & Parasite (O&P) test or an "E. histolytica" fecal antigen assay is the proper assay for intestinal infections. Since antibodies may persist for years after clinical cure, a positive serological result may not necessarily indicate an active infection. A negative serological result however can be equally important in excluding suspected tissue invasion by "E. histolytica".

The diagnosis of shigellosis is made by isolating the organism from diarrheal fecal sample cultures. "Shigella" species are negative for motility and are generally not lactose fermenters, but "S. sonnei" can ferment lactose. They typically do not produce gas from carbohydrates (with the exception of certain strains of "S. flexneri") and tend to be overall biochemically inert. "Shigella" should also be urea hydrolysis negative. When inoculated to a triple sugar iron slant, they react as follows: K/A, gas -, and HS -. Indole reactions are mixed, positive and negative, with the exception of "S. sonnei", which is always indole negative. Growth on Hektoen enteric agar produces bluish-green colonies for "Shigella" and bluish-green colonies with black centers for "Salmonella".

Simple precautions can be taken to prevent getting shigellosis: wash hands before handling food and thoroughly cook all food before eating. The primary prevention methods are improved sanitation and personal and food hygiene, but a low-cost and efficacious vaccine would complement these methods.

Since shigellosis is spread very quickly among children, keeping infected children out of daycare for 24 hours after their symptoms have disappeared, will decrease the occurrence of shigellosis in daycares.

Owing to the non-specific nature of the presentation of symptoms, diagnosis of malaria in non-endemic areas requires a high degree of suspicion, which might be elicited by any of the following: recent travel history, enlarged spleen, fever, low number of platelets in the blood, and higher-than-normal levels of bilirubin in the blood combined with a normal level of white blood cells. Reports in 2016 and 2017 from countries were malaria is common suggest high levels of over diagnosis due to insufficient or inaccurate laboratory testing.

Malaria is usually confirmed by the microscopic examination of blood films or by antigen-based rapid diagnostic tests (RDT). In some areas, RDTs need to be able to distinguish whether the malaria symptoms are caused by "Plasmodium falciparum" or by other species of parasites since treatment strategies could differ for non-"P. falciparum" infections. Microscopy is the most commonly used method to detect the malarial parasite—about 165 million blood films were examined for malaria in 2010. Despite its widespread usage, diagnosis by microscopy suffers from two main drawbacks: many settings (especially rural) are not equipped to perform the test, and the accuracy of the results depends on both the skill of the person examining the blood film and the levels of the parasite in the blood. The sensitivity of blood films ranges from 75–90% in optimum conditions, to as low as 50%. Commercially available RDTs are often more accurate than blood films at predicting the presence of malaria parasites, but they are widely variable in diagnostic sensitivity and specificity depending on manufacturer, and are unable to tell how many parasites are present.

In regions where laboratory tests are readily available, malaria should be suspected, and tested for, in any unwell person who has been in an area where malaria is endemic. In areas that cannot afford laboratory diagnostic tests, it has become common to use only a history of fever as the indication to treat for malaria—thus the common teaching "fever equals malaria unless proven otherwise". A drawback of this practice is overdiagnosis of malaria and mismanagement of non-malarial fever, which wastes limited resources, erodes confidence in the health care system, and contributes to drug resistance. Although polymerase chain reaction-based tests have been developed, they are not widely used in areas where malaria is common as of 2012, due to their complexity.

Malaria is classified into either "severe" or "uncomplicated" by the World Health Organization (WHO). It is deemed severe when "any" of the following criteria are present, otherwise it is considered uncomplicated.

- Decreased consciousness

- Significant weakness such that the person is unable to walk

- Inability to feed

- Two or more convulsions

- Low blood pressure (less than 70 mmHg in adults and 50 mmHg in children)

- Breathing problems

- Circulatory shock

- Kidney failure or hemoglobin in the urine

- Bleeding problems, or hemoglobin less than 50 g/L (5 g/dL)

- Pulmonary oedema

- Blood glucose less than 2.2 mmol/L (40 mg/dL)

- Acidosis or lactate levels of greater than 5 mmol/L

- A parasite level in the blood of greater than 100,000 per microlitre (µL) in low-intensity transmission areas, or 250,000 per µL in high-intensity transmission areas

Cerebral malaria is defined as a severe "P. falciparum"-malaria presenting with neurological symptoms, including coma (with a Glasgow coma scale less than 11, or a Blantyre coma scale greater than 3), or with a coma that lasts longer than 30 minutes after a seizure.

Various types of malaria have been called by the names below:

To help prevent the spread of amoebiasis around the home :

- Wash hands thoroughly with soap and hot running water for at least 10 seconds after using the toilet or changing a baby's diaper, and before handling food.

- Clean bathrooms and toilets often; pay particular attention to toilet seats and taps.

- Avoid sharing towels or face washers.

To help prevent infection:

- Avoid raw vegetables when in endemic areas, as they may have been fertilized using human feces.

- Boil water or treat with iodine tablets.

- Avoid eating street foods especially in public places where others are sharing sauces in one container

Good sanitary practice, as well as responsible sewage disposal or treatment, are necessary for the prevention of "E. histolytica" infection on an endemic level. "E.histolytica" cysts are usually resistant to chlorination, therefore sedimentation and filtration of water supplies are necessary to reduce the incidence of infection.

"E. histolytica" cysts may be recovered from contaminated food by methods similar to those used for recovering "Giardia lamblia" cysts from feces. Filtration is probably the most practical method for recovery from drinking water and liquid foods. "E. histolytica" cysts must be distinguished from cysts of other parasitic (but nonpathogenic) protozoa and from cysts of free-living protozoa as discussed above. Recovery procedures are not very accurate; cysts are easily lost or damaged beyond recognition, which leads to many falsely negative results in recovery tests.

Dysentery is initially managed by maintaining fluid intake using oral rehydration therapy. If this treatment cannot be adequately maintained due to vomiting or the profuseness of diarrhea, hospital admission may be required for intravenous fluid replacement. Ideally, no antimicrobial therapy should be administered until microbiological microscopy and culture studies have established the specific infection involved. When laboratory services are not available, it may be necessary to administer a combination of drugs, including an amoebicidal drug to kill the parasite and an antibiotic to treat any associated bacterial infection.

Anyone with bloody diarrhea needs immediate medical help. Treatment often starts with an oral rehydrating solution—water mixed with salt and carbohydrates—to prevent dehydration. (Emergency relief services often distribute inexpensive packets of sugars and mineral salts that can be mixed with clean water and used to restore lifesaving fluids in dehydrated children gravely ill from dysentery.)

If "Shigella" is suspected and it is not too severe, the doctor may recommend letting it run its course—usually less than a week. The patient will be advised to replace fluids lost through diarrhea. If the infection is severe, the doctor may prescribe antibiotics, such as ciprofloxacin or TMP-SMX (Bactrim). Unfortunately, many strains of "Shigella" are becoming resistant to common antibiotics, and effective medications are often in short supply in developing countries. If necessary, a doctor may have to reserve antibiotics for those at highest risk for death, including young children, people over 50, and anyone suffering from dehydration or malnutrition.

No vaccine is available. There are several "Shigella" vaccine candidates in various stages of development that could reduce the incidence of dysentery in endemic countries, as well as in travelers suffering from traveler's diarrhea.

The oral cholera vaccine, while effective for prevention of cholera, is of questionable use for prevention of TD. A 2008 review found tentative evidence of benefit. A 2015 review stated it may be reasonable for those at high risk of complications from TD. Several vaccine candidates targeting ETEC or "Shigella" are in various stages of development.

Recommendations include avoidance of questionable foods and drinks, on the assumption that TD is fundamentally a sanitation failure, leading to bacterial contamination of drinking water and food. While the effectiveness of this strategy has been questioned, given that travelers have little or no control over sanitation in hotels and restaurants, and little evidence supports the contention that food vigilance reduces the risk of contracting TD, guidelines continue to recommend basic, common-sense precautions when making food and beverage choices:

- Maintain good hygiene and use only safe water for drinking and brushing teeth.

- Safe beverages include bottled water, bottled carbonated beverages, and water boiled or appropriately treated by the traveler (as described below). Caution should be exercised with tea, coffee, and other hot beverages that may be only heated, not boiled.

- In restaurants, insist that bottled water be unsealed in your presence; reports of locals filling empty bottles with untreated tap water and reselling them as purified water have surfaced. When in doubt, a bottled carbonated beverage is the safest choice, since it is difficult to simulate carbonation when refilling a used bottle.

- Avoid ice, which may not have been made with safe water.

- Avoid green salads, because the lettuce and other uncooked ingredients are unlikely to have been washed with safe water.

- Avoid eating raw fruits and vegetables unless cleaned and peeled personally.

If handled properly, thoroughly cooked fresh and packaged foods are usually safe. Raw or undercooked meat and seafood should be avoided. Unpasteurized milk, dairy products, mayonnaise, and pastry icing are associated with increased risk for TD, as are foods and beverages purchased from street vendors and other establishments where unhygienic conditions may be present.

Numerous studies have shown that improvements in drinking water and sanitation (WASH) lead to decreased risks of diarrhoea. Such improvements might include for example use of water filters, provision of high-quality piped water and sewer connections.

In institutions, communities, and households, interventions that promote hand washing with soap lead to significant reductions in the incidence of diarrhea. The same applies to preventing open defecation at a community-wide level and providing access to improved sanitation. This includes use of toilets and implementation of the entire sanitation chain connected to the toilets (collection, transport, disposal or reuse of human excreta).

Breastfeeding practices have been shown to have a dramatic effect on the incidence of diarrheal disease in poor populations. Studies across a number of developing nations have shown that those who receive exclusive breastfeeding during their first 6 months of life are better protected against infection with diarrheal diseases. Exclusive breastfeeding is currently recommended during, at least, the first six months of an infant's life by the WHO.

"Campylobacter" organisms can be detected by performing a Gram stain of a stool sample with high specificity and a sensitivity of ~60%, but are most often diagnosed by stool culture. Fecal leukocytes should be present and indicate the diarrhea to be inflammatory in nature. Methods currently being developed to detect the presence of campylobacter organisms include antigen testing via an EIA or PCR.

Diagnosis is usually performed by submitting multiple stool samples for examination by a parasitologist in a procedure known as an ova and parasite examination. About 30% of children with "D. fragilis" infection exhibit peripheral blood eosinophilia.

A minimum of three stool specimens having been immediately fixed in polyvinyl alcohol fixative, sodium acetate-acetic acid-formalin fixative, or Schaudinn's fixative should be submitted, as the protozoan does not remain morphologically identifiable for long. All specimens, regardless of consistency, are permanently stained prior to microscopic examination with an oil immersion lens. The disease may remain cryptic due to the lack of a cyst stage if these recommendations are not followed.

The trophozoite forms have been recovered from formed stool, thus the need to perform the ova and parasite examination on specimens other than liquid or soft stools. DNA fragment analysis provides excellent sensitivity and specificity when compared to microscopy for the detection of "D. fragilis" and both methods should be employed in laboratories with PCR capability. The most sensitive detection method is parasite culture, and the culture medium requires the addition of rice starch.

An indirect fluorescent antibody (IFA) for fixed stool specimens has been developed.

1. One researcher investigated the phenomenon of symptomatic relapse following treatment of infection with "D. fragilis" in association with its apparent disappearance from stool samples. The organism could still be detected in patients through colonoscopy or by examining stool samples taken in conjunction with a saline laxative.

2. A study found that trichrome staining, a traditional method for identification, had a sensitivity of 36% (9/25) when compared to stool culture.

3. An additional study found that the sensitivity of staining was 50% (2/4), and that the organism could be successfully cultured in stool specimens up to 12-hours old that were kept at room temperature.

The World Health Organization recommends the following:

- Food should be properly cooked and hot when served.

- Consume only pasteurized or boiled milk and milk products, never raw milk products.

- Make sure that ice is from safe water.

- If you are not sure of the safety of drinking water, boil it, or disinfect it with chemical disinfectant.

- Wash hands thoroughly and frequently with soap, especially after using the toilet and after contact with pets and farm animals.

- Wash fruits and vegetables thoroughly, especially if they are to be eaten raw. Peel fruits and vegetables whenever possible.

- Food handlers, professionals and at home, should observe hygienic rules during food preparation.

- Professional food handlers should immediately report to their employer any fever, diarrhea, vomiting or visible infected skin lesions.

The gold standard for diagnosis is visualization of the amastigotes in splenic aspirate or bone marrow aspirate. This is a technically challenging procedure that is frequently unavailable in areas of the world where visceral leishmaniasis is endemic.

Serological testing is much more frequently used in areas where leishmaniasis is endemic. A 2014 Cochrane review evaluated different rapid diagnostic tests. One of them (the rK39 immunochromatographic test) gave correct, positive results in 92% of the people with visceral leishmaniasis and it gave correct, negative results in 92% of the people who did not have the disease. A second rapid test (called latex agglutination test) gave correct, positive results in 64% of the people with the disease and it gave correct, negative results in 93% of the people without the disease. Other types of tests have not been studied thoroughly enough to ascertain their efficacy.

The K39 dipstick test is easy to perform, and village health workers can be easily trained to use it. The kit may be stored at ambient temperature and no additional equipment needs to be carried to remote areas. The DAT anti-leishmania antigen test, standard within MSF, is much more cumbersome to use and appears not to have any advantages over the K39 test.

There are a number of problems with serological testing: in highly endemic areas, not everyone who becomes infected will actually develop clinical disease or require treatment. Indeed, up to 32% of the healthy population may test positive, but not require treatment. Conversely, because serological tests look for an immune response and not for the organism itself, the test does not become negative after the patient is cured, it cannot be used as a check for cure, or to check for re-infection or relapse. Likewise, patients with abnormal immune systems (e.g., HIV infection) will have false-negative tests.

Other tests being developed include detects erythrosalicylic acid.

Concomitant pinworm infection should also be excluded, although the association has not been proven. Successful treatment of the infection with iodoquinol, doxycycline, metronidazole, paromomycin, and secnidazole has been reported. Resistance requires the use of combination therapy to eradicate the organism. All persons living in the same residence should be screened for "D. fragilis", as asymptomatic carriers may provide a source of repeated infection. Paromomycin is an effective prophylactic for travellers who will encounter poor sanitation and unsafe drinking water.

Diagnosis depends on finding characteristic worm eggs on microscopic examination of the stools, although this is not possible in early infection. Early signs of infection in most dogs include limbular limping and anal itching. The eggs are oval or elliptical, measuring 60 µm by 40 µm, colorless, not bile stained and with a thin transparent hyaline shell membrane. When released by the worm in the intestine, the egg contains an unsegmented ovum. During its passage down the intestine, the ovum develops and thus the eggs passed in feces have a segmented ovum, usually with 4 to 8 blastomeres.

As the eggs of both "Ancylostoma" and "Necator" (and most other hookworm species) are indistinguishable, to identify the genus, they must be cultured in the lab to allow larvae to hatch out. If the fecal sample is left for a day or more under tropical conditions, the larvae will have hatched out, so eggs might no longer be evident. In such a case, it is essential to distinguish hookworms from "Strongyloides" larvae, as infection with the latter has more serious implications and requires different management. The larvae of the two hookworm species can also be distinguished microscopically, although this would not be done routinely, but usually for research purposes. Adult worms are rarely seen (except via endoscopy, surgery or autopsy), but if found, would allow definitive identification of the species. Classification can be performed based on the length of the buccal cavity, the space between the oral opening and the esophagus: hookworm rhabditoform larvae have long buccal cavities whereas "Strongyloides" rhabditoform larvae have short buccal cavities.

Recent research has focused on the development of DNA-based tools for diagnosis of infection, specific identification of hookworm, and analysis of genetic variability within hookworm populations. Because hookworm eggs are often indistinguishable from other parasitic eggs, PCR assays could serve as a molecular approach for accurate diagnosis of hookworm in the feces.

Evaluation of numerous public health interventions has generally shown that improvement in each individual component ordinarily attributed to poverty (for example, sanitation, health education and underlying nutrition status) often have minimal impact on transmission. For example, one study found that the introduction of latrines into a resource-limited community only reduced the prevalence of hookworm infection by four percent. However, another study in Salvador, Brazil found that improved drainage and sewerage had a significant impact (p<0.0001) on the prevalence of hookworm infection but no impact at all on the intensity of hookworm infection. This seems to suggest that environmental control alone has a limited but incomplete effect on the transmission of hookworms. It is imperative, therefore, that more research is performed to understand the efficacy and sustainability of integrated programs that combine numerous preventive methods including education, sanitation, and treatment.

There are no vaccines or preventive drugs for visceral leishmaniasis. The most effective method to prevent infection is to protect from sand fly bites. To decrease the risk of being bitten, these precautionary measures are suggested:

- Outdoors:

1. Avoid outdoor activities, especially from dusk to dawn, when sand flies generally are the most active.

2. When outdoors (or in unprotected quarters), minimize the amount of exposed (uncovered) skin to the extent that is tolerable in the climate. Wear long-sleeved shirts, long pants, and socks; and tuck your shirt into your pants.

3. Apply insect repellent to exposed skin and under the ends of sleeves and pant legs. Follow the instructions on the label of the repellent. The most effective repellents generally are those that contain the chemical DEET (N,N-diethylmetatoluamide).

- Indoors:

1. Stay in well-screened or air-conditioned areas.

2. Keep in mind that sand flies are much smaller than mosquitoes and therefore can get through smaller holes.

3. Spray living/sleeping areas with an insecticide to kill insects.

4. If you are not sleeping in a well-screened or air-conditioned area, use a bed net and tuck it under your mattress. If possible, use a bed net that has been soaked in or sprayed with a pyrethroid-containing insecticide. The same treatment can be applied to screens, curtains, sheets, and clothing (clothing should be retreated after five washings)."

On February 2012, the nonprofit Infectious Disease Research Institute launched a clinical trial of the visceral leishmaniasis vaccine. The vaccine is a recombinant form of two fused Leishmania parasite proteins with an adjuvant. Two phase 1 clinical trials with healthy volunteers are to be conducted. The first one takes place in Washington (state) and is followed by a trial in India.

Enteroinvasive "Escherichia coli" (EIEC) is a type of pathogenic bacteria whose infection causes a syndrome that is identical to shigellosis, with profuse diarrhea and high fever. EIEC are highly invasive, and they use adhesin proteins to bind to and enter intestinal cells. They produce no toxins, but severely damage the intestinal wall through mechanical cell destruction.

It is closely related to "Shigella".

After the "E. coli" strain penetrates through the epithelial wall, the endocytosis vacuole gets lysed, the strain multiplies using the host cell machinery, and extends to the adjacent epithelial cell. In addition, the plasmid of the strain carries genes for a type III secretion system that is used as the virulent factor. Although it is an invasive disease, the invasion usually does not pass the submucosal layer. The similar pathology to shigellosis may be because both strains of bacteria share some virulent factors. The invasion of the cells can trigger a mild form of diarrhea or dysentery, often mistaken for dysentery caused by "Shigella" species. The illness is characterized by the appearance of blood and mucus in the stools of infected individuals or a condition called colitis.

Dysentery caused by EIEC usually occurs within 12 to 72 hours following the ingestion of contaminated food. The illness is characterized by abdominal cramps, diarrhea, vomiting, fever, chills, and a generalized malaise. Dysentery caused by this organism is generally self-limiting with no known complications.

Enterovirulent classes of "E. coli" are referred to as the EEC group (enterovirulent "E. coli"):

1. Enteroinvasive "E. coli" (EIEC) invades (passes into) the intestinal wall to produce severe diarrhea.

2. Enterohemorrhagic "E. coli" (EHEC): A type of EHEC, "E. coli" 0157:H7, can cause bloody diarrhea and hemolytic uremic syndrome (anemia and kidney failure).

3. Enterotoxigenic "E. coli" (ETEC) produces a toxin that acts on the intestinal lining, and is the most common cause of traveler's diarrhea.

4. Enteropathogenic "E. coli" (EPEC) can cause diarrhea outbreaks in newborn nurseries.

5. Enteroaggregative "E. coli" (EAggEC) can cause acute and chronic (long-lasting) diarrhea in children.

It is currently unknown what foods may harbor EIEC, but any food contaminated with human feces from an ill individual, either directly or via contaminated water, could cause disease in others. Outbreaks have been associated with hamburger meat and unpasteurized milk.