In addition to symptoms related to the provoking cause, sepsis is frequently associated with either fever, low body temperature, rapid breathing, elevated heart rate, confusion, and edema. Early signs are a rapid heart rate, decreased urination, and high blood sugar. Signs of established sepsis include confusion, metabolic acidosis (which may be accompanied by faster breathing and lead to a respiratory alkalosis), low blood pressure due to decreased systemic vascular resistance, higher cardiac output, and dysfunctions of blood coagulation (where clotting may lead to organ failure).

The drop in blood pressure seen in sepsis may lead to shock. This may result in light-headedness. Bruising or intense bleeding may occur.

The differential diagnosis for sepsis is broad and has to examine (to exclude) the noninfectious conditions that may cause the systemic signs of SIRS: alcohol withdrawal, acute pancreatitis, burns, pulmonary embolism, thyrotoxicosis, anaphylaxis, adrenal insufficiency, and neurogenic shock. Hyperinflammatory syndromes such as hemophagocytic lymphohistiocytosis (HLH) may have similar symptoms and should also be included in differential diagnosis.

Respiratory infection in humans is relatively rare and presents as two stages. It infects the lymph nodes in the chest first, rather than the lungs themselves, a condition called hemorrhagic mediastinitis, causing bloody fluid to accumulate in the chest cavity, therefore causing shortness of breath. The first stage causes cold and flu-like symptoms. Symptoms include fever, shortness of breath, cough, fatigue, and chills. This can last hours to days. Often, many fatalities from inhalational anthrax are when the first stage is mistaken for the cold or flu and the victim does not seek treatment until the second stage, which is 90% fatal. The second (pneumonia) stage occurs when the infection spreads from the lymph nodes to the lungs. Symptoms of the second stage develop suddenly after hours or days of the first stage. Symptoms include high fever, extreme shortness of breath, shock, and rapid death within 48 hours in fatal cases. Historical mortality rates were over 85%, but when treated early (seen in the 2001 anthrax attacks), observed case fatality rate dropped to 45%. Distinguishing pulmonary anthrax from more common causes of respiratory illness is essential to avoiding delays in diagnosis and thereby improving outcomes. An algorithm for this purpose has been developed.

Cutaneous anthrax, also known as Hide porter's disease, is when anthrax occurs on the skin. It is the most common form (>90% of anthrax cases). Cutaneous anthrax is also the least dangerous form of anthrax (less than 1% mortality rate with treatment). Cutaneous anthrax presents as a boil-like skin lesion that eventually forms an ulcer with a black center (eschar). The black eschar often shows up as a large, painless, necrotic ulcer (beginning as an irritating and itchy skin lesion or blister that is dark and usually concentrated as a black dot, somewhat resembling bread mold) at the site of infection. In general, cutaneous infections form within the site of spore penetration between two and five days after exposure. Unlike bruises or most other lesions, cutaneous anthrax infections normally do not cause pain. Nearby lymph nodes may become infected, reddened, swollen, and painful. A scab forms over the lesion soon, and falls off in a few weeks. Complete recovery may take longer.

Cutaneous anthrax is typically caused when "B. anthracis" spores enter through cuts on the skin. This form is found most commonly when humans handle infected animals and/or animal products.

Cutaneous anthrax is rarely fatal if treated, because the infection area is limited to the skin, preventing the lethal factor, edema factor, and protective antigen from entering and destroying a vital organ. Without treatment, about 20% of cutaneous skin infection cases progress to toxemia and death.

Infection with "Y. enterocolitica" can cause a variety of symptoms depending on the age of the person infected, therefore it's often referred to as "monkey of diseases". Common symptoms in children are fever, abdominal pain, and diarrhea, which is often bloody. Symptoms typically develop 4 to 7 days after exposure and may last 1 to 3 weeks or longer. In older children and adults, right-sided abdominal pain and fever may be the predominant symptoms, and may be confused with appendicitis. In a small proportion of cases, complications such as skin rash, joint pains, ileitis, erythema nodosum, and sometimes septicemia, acute arthritis or the spread of bacteria to the bloodstream (bacteremia) can occur.

Yersiniosis is an infectious disease caused by a bacterium of the genus "Yersinia". In the United States, most yersiniosis infections among humans are caused by "Yersinia enterocolitica". The infection by "Y. enterocolitica" is also known as pseudotuberculosis. Yersiniosis is mentioned as a specific zoonotic disease to prevent outbreaks in European Council Directive 92/117/EEC.

Infection with " Y . enterocolitica" occurs most often in young children. The infection is thought to be contracted through the consumption of undercooked meat products, unpasteurized milk, or water contaminated by the bacteria. It has been also sometimes associated with handling raw chitterlings.

Another bacterium of the same genus, "Yersinia pestis", is the cause of Plague.

In acute cases, a green diarrhea can be an early symptom.

The most typical symptom, in chronic cases, is the swelling of the wattles. It is more frequent in resistant local breeds. Rather than a general infection, localized infections are more characteristic. These often occur in the respiratory tract including the sinuses and pneumatoics bones, hock joints, sternal bursa, foot pads, peritoneal cavity and oviducts.

In acute cases, the most typical p.m. lesion is the petechiae observed in the epicardial fatty tissue. Necrotic foci on liver are usually found and general hyperemia is common. Due to the speed of infection and mortality, birds are in good body condition and do not exhibit the signs of prolonged illness.

Fowl cholera is also called avian cholera, avian pasteurellosis, avian hemorrhagic septicemia.

It is the most common pasteurellosis of poultry. As the causative agent is "Pasteurella multocida", it is considered as a zoonosis.

Adult birds and old chickens are more susceptible. In parental flocks, cocks are far more susceptible than hens.

Besides chickens, the disease also concerns turkeys, ducks, geese, raptors, and canaries. Turkeys are particularly sensitive, with mortality ranging to 65%.

The recognition of this pathological condition is of ever increasing importance for differential diagnosis with avian influenza.

A hospital-acquired infection (HAI), also known as a nosocomial infection, is an infection that is acquired in a hospital or other health care facility. To emphasize both hospital and nonhospital settings, it is sometimes instead called a health care–associated infection (HAI or HCAI). Such an infection can be acquired in hospital, nursing home, rehabilitation facility, outpatient clinic, or other clinical settings. Infection is spread to the susceptible patient in the clinical setting by various means. Health care staff can spread infection, in addition to contaminated equipment, bed linens, or air droplets. The infection can originate from the outside environment, another infected patient, staff that may be infected, or in some cases, the source of the infection cannot be determined. In some cases the microorganism originates from the patient's own skin microbiota, becoming opportunistic after surgery or other procedures that compromise the protective skin barrier. Though the patient may have contracted the infection from their own skin, the infection is still considered nosocomial since it develops in the health care setting.

In the United States, the Centers for Disease Control and Prevention estimated roughly 1.7 million hospital-associated infections, from all types of microorganisms, including bacteria and fungi combined, cause or contribute to 99,000 deaths each year. In Europe, where hospital surveys have been conducted, the category of gram-negative infections are estimated to account for two-thirds of the 25,000 deaths each year. Nosocomial infections can cause severe pneumonia and infections of the urinary tract, bloodstream and other parts of the body. Many types are difficult to treat with antibiotics. In addition, antibiotic resistance can complicate treatment.

Septic shock is a serious medical condition that occurs when sepsis, which is organ injury or damage in response to infection, leads to dangerously low blood pressure and abnormalities in cellular metabolism.

The primary infection is most commonly caused by bacteria, but also may be by fungi, viruses or parasites. It may be located in any part of the body, but most commonly in the lungs, brain, urinary tract, skin or abdominal organs. It can cause multiple organ dysfunction syndrome (formerly known as multiple organ failure) and death.

Frequently, people with septic shock are cared for in intensive care units. It most commonly affects children, immunocompromised individuals, and the elderly, as their immune systems cannot deal with infection so effectively as those of healthy adults. The mortality rate from septic shock is approximately 25–50%.

Living fish afflicted with VHS may appear listless or limp, hang just

beneath the surface, or swim very abnormally, such as constant flashing

circling due to the tropism of the virus for the brain.

External signs may include darker coloration, exophthalmia ("pop eye"),

pale or red-dotted gills, sunken eyes, and bleeding around orbits (eye sockets) and

at base of fins.

Genetics researchers at the Lake Erie Research Center at the University of Toledo are developing a test that will speed diagnosis from a month to a matter of hours.

An emerging infectious disease (EID) is an infectious disease whose incidence has increased in the past 20 years and could increase in the near future. Emerging infections account for at least 12% of all human pathogens. EIDs are caused by newly identified species or strains (e.g. Severe acute respiratory syndrome, HIV/AIDS) that may have evolved from a known infection (e.g. influenza) or spread to a new population (e.g. West Nile fever) or to an area undergoing ecologic transformation (e.g. Lyme disease), or be "reemerging" infections, like drug resistant tuberculosis. Nosocomial (hospital-acquired) infections, such as methicillin-resistant Staphylococcus aureus are emerging in hospitals, and extremely problematic in that they are resistant to many antibiotics. Of growing concern are adverse synergistic interactions between emerging diseases and other infectious and non-infectious conditions leading to the development of novel syndemics. Many emerging diseases are zoonotic - an animal reservoir incubates the organism, with only occasional transmission into human populations.

VHSV is a hemorrhagic disease, meaning it causes bleeding. Internally,

the virus can cause petechial hemorrhaging (tiny spots of blood) in internal

muscle tissue, and petechial or severe hemorrhaging in internal organs and

other tissues. Internal hemorrhaging can be observed as red spots inside

a dead fish, particularly around the kidney, spleen, and intestines, as

well as the swim bladder, which would normally have a clear membrane.

The liver may be pale, mottled with red hyperemic areas, the kidney

may be swollen and unusually red, the spleen may be swollen, and the digestive

tract may be empty.

External signs are not always present, but if they are, hemorrhaging on the

skin's surface can appear as anywhere from tiny red dots (petechiae) to

large red patches.

A superinfection is a second infection superimposed on an earlier one, especially by a different microbial agent of exogenous or endogenous origin, that is resistant to the treatment being used against the first infection. Examples of this in bacteriology are the overgrowth of endogenous "Clostridium difficile" which occurs following treatment with a broad-spectrum antibiotic, and pneumonia or septicemia from "Pseudomonas aeruginosa" in some immuno-compromised patients.

In virology, the definition is slightly different. Superinfection is the process by which a cell that has previously been infected by one virus gets co-infected with a different strain of the virus, or another virus, at a later point in time. Viral superinfections may be resistant to the antiviral drug or drugs that were being used to treat the original infection. Viral superinfections may also be less susceptible to the host's immune response.

The symptoms are like those associated with many other febrile diseases, but with emphasis on muscular pain and night sweats. The duration of the disease can vary from a few weeks to many months or even years.

In the first stage of the disease, sepsis occurs and leads to the classic triad of undulant fevers, sweating (often with characteristic foul moldy smell sometimes likened to wet hay), and migratory arthralgia and myalgia (joint and muscle pain). Blood tests characteristically reveal a low number of white blood cells and red blood cells, show some elevation of liver enzymes such as aspartate aminotransferase (AST) and alanine aminotransferase (ALT), and demonstrate positive Bengal Rose and Huddleston reactions. Gastrointestinal symptoms occur in 70% of cases and include nausea, vomiting, decreased appetite, unintentional weight loss, abdominal pain, constipation, diarrhea, an enlarged liver, liver inflammation, liver abscess, and an enlarged spleen.

This complex is, at least in Portugal, Israel, and Jordan, known as Malta fever. During episodes of Malta fever, melitococcemia (presence of brucellae in blood) can usually be demonstrated by means of blood culture in tryptose medium or Albini medium. If untreated, the disease can give origin to focalizations or become chronic. The focalizations of brucellosis occur usually in bones and joints and spondylodiscitis of the lumbar spine accompanied by sacroiliitis is very characteristic of this disease. Orchitis is also common in men.

Diagnosis of brucellosis relies on:

1. Demonstration of the agent: blood cultures in tryptose broth, bone marrow cultures. The growth of brucellae is extremely slow (they can take up to two months to grow) and the culture poses a risk to laboratory personnel due to high infectivity of brucellae.

2. Demonstration of antibodies against the agent either with the classic Huddleson, Wright, and/or Bengal Rose reactions, either with ELISA or the 2-mercaptoethanol assay for IgM antibodies associated with chronic disease

3. Histologic evidence of granulomatous hepatitis on hepatic biopsy

4. Radiologic alterations in infected vertebrae: the Pedro Pons sign (preferential erosion of the anterosuperior corner of lumbar vertebrae) and marked osteophytosis are suspicious of brucellic spondylitis.

The consequences of "Brucella" infection are highly variable and may include arthritis, spondylitis, thrombocytopenia, meningitis, uveitis, optic neuritis, endocarditis, and various neurological disorders collectively known as neurobrucellosis.

Septic shock is a subclass of distributive shock, a condition in which abnormal distribution of blood flow in the smallest blood vessels results in inadequate blood supply to the body tissues, resulting in ischemia and organ dysfunction. Septic shock refers specifically to distributive shock due to sepsis as a result of infection.

Septic shock may be defined as sepsis-induced low blood pressure that persists despite treatment with intravenous fluids. Low blood pressure reduces tissue perfusion pressure, causing the tissue hypoxia that is characteristic of shock. Cytokines released in a large scale inflammatory response result in massive vasodilation, increased capillary permeability, decreased systemic vascular resistance, and low blood pressure. Finally, in an attempt to offset decreased blood pressure, ventricular dilatation and myocardial dysfunction occur.

Septic shock may be regarded as a stage of SIRS (Systemic Inflammatory Response Syndrome), in which sepsis, severe sepsis and multiple organ dysfunction syndrome (MODS) represent different stages of a pathophysiological process. If an organism cannot cope with an infection, it may lead to a systemic response - sepsis, which may further progress to severe sepsis, septic shock, organ failure, and eventually, result in death.

On post-mortem examination (necropsy), the most obvious gross lesion is subcutaneous oedema in the submandibular and pectoral (brisket) regions. Petechial haemorrhages are found subcutaneously and in the thoracic cavity. In addition, congestion and various degrees of consolidation of the lung may occur. Animals that die within 24–36 hours, have only few petechial haemorrhages on the heart and generalised congestion of the lung, while in animals that die after 72 hours, petechial and ecchymotic haemorrhages were more evident and lung consolidation are more extensive.

Signs and symptoms usually include a fever greater than , chills, low abdominal pain, and possibly bad smelling vaginal discharge.

A wide variety of clinical signs have been described for HS in cattle and buffaloes. The incubation periods (the time between exposure and observable disease) for buffalo calves 4–10 months of age varies according to the route of infection. The incubation period is 12–14 hours, approximately 30 hours and 46–80 hours for subcutaneous infection, oral infection and natural exposure, respectively.

There is variability in the duration of the clinical course of the disease. In the case of experimental subcutaneous infection, the clinical course lasted only a few hours, while it persisted for 2–5 days following oral infection and in buffaloes and cattle that had been exposed to naturally-infected animals. It has also been recorded from field observations that the clinical courses of per-acute and acute cases were 4–12 hours and 2–3 days, respectively.

Generally, progression of the disease in buffaloes and cattle is divided into three phases. Phase one is characterised by fever, with a rectal temperature of , loss of appetite and depression. Phase two is typified by increased respiration rate (40–50/minute), laboured breathing, clear nasal discharge (turns opaque and mucopurulent as the disease progresses), salivation and submandibular oedema spreading to the pectoral (brisket) region and even to the forelegs. Finally, in phase three, there is typically recumbency, continued acute respiratory distress and terminal septicaemia. The three phases overlap when the disease course is short. In general, buffaloes have a more acute onset of disease than cattle, with a shorter duration.

A "vaccine-preventable disease" is an infectious disease for which an effective preventive vaccine exists. If a person acquires a vaccine-preventable disease and dies from it, the death is considered a vaccine-preventable death.

The most common and serious vaccine-preventable diseases tracked by the World Health Organization (WHO) are: diphtheria, "Haemophilus influenzae" serotype b infection, hepatitis B, measles, meningitis, mumps, pertussis, poliomyelitis, rubella, tetanus, tuberculosis, and yellow fever. The WHO reports licensed vaccines being available to prevent, or contribute to the prevention and control of, 25 vaccine-preventable infections.

After childbirth a woman's genital tract has a large bare surface, which is prone to infection. Infection may be limited to the cavity and wall of her uterus, or it may spread beyond to cause septicaemia (blood poisoning) or other illnesses, especially when her resistance has been lowered by a long labour or severe bleeding. Puerperal infection is most common on the raw surface of the interior of the uterus after separation of the placenta (afterbirth); but pathogenic organisms may also affect lacerations of any part of the genital tract. By whatever portal, they can invade the bloodstream and lymph system to cause septicemia, cellulitis (inflammation of connective tissue), and pelvic or generalized peritonitis (inflammation of the abdominal lining). The severity of the illness depends on the virulence of the infecting organism, the resistance of the invaded tissues, and the general health of the woman. Organisms commonly producing this infection are "Streptococcus pyogenes"; staphylococci (inhabitants of the skin and of pimples, carbuncles, and many other pustular eruptions); the anaerobic streptococci, which flourish in devitalized tissues such as may be present after long and injurious labour and unskilled instrumental delivery; "Escherichia coli" and "Clostridium perfringens" (inhabitants of the lower bowel); and "Clostridium tetani".

In sheep, the disease is also called the "circling disease". The most obvious signs for the veterinarians are neurological, especially lateral deviation of the neck and head.

Pseudomonas infection refers to a disease caused by one of the species of the genus "Pseudomonas".

"Pseudomonas sp. KUMS3" could be considered

as an opportunistic pathogen, which can survive on the

fish surface or in water or in the gut and may cause disease

when unfavorable conditions develop.

"P. aeruginosa" is an opportunistic human pathogen, most commonly affecting immunocompromised patients, such as those with cystic fibrosis or AIDS. Infection can affect many different parts of the body, but infections typically target the respiratory tract (e.g. patients with CF or those on mechanical ventilation), causing bacterial pneumonia. In a surveillance study between 1986 and 1989, P. aeruginosa was the third leading cause of all nosocomial infections, and specifically the number one leading cause of hospital-acquired pneumonia and third leading cause of hospital-acquired UTI. Treatment of such infections can be difficult due to multiple antibiotic resistance, and in the United States, there was an increase in MDRPA (Multidrug-resistant "Pseudomonas aeruginosa") resistant to ceftazidime, ciprofloxacin, and aminoglycosides, from 0.9% in 1994 to 5.6% in 2002.

"P. oryzihabitans" can also be a human pathogen, although infections are rare. It can cause peritonitis, endophthalmitis, septicemia and bacteremia. Similar symptoms although also very rare can be seen by infections of "P. luteola".

"P. plecoglossicida" is a fish pathogenic species, causing hemorrhagic ascites in the ayu ("Plecoglossus altivelis"). "P. anguilliseptica" is also a fish pathogen.

Due to their hemolytic activity, even non-pathogenic species of "Pseudomonas" can occasionally become a problem in clinical settings, where they have been known to infect blood transfusions.

Indwelling catheters have recently been identified with hospital acquired infections. Procedures using Intravascular Antimicrobial Lock Therapy can reduce infections that are unexposed to blood-borne antibiotics. Introducing antibiotics, including ethanol, into the catheter (without flushing it into the bloodstream) reduces the formation of biofilms.

Contact transmission is divided into two subgroups: direct-contact transmission and indirect-contact transmission.

Listeriosis is an infectious but not contagious disease caused by the bacterium "Listeria monocytogenes", far more common in domestics animals (domestic mammals and poultry), especially ruminants, than in human beings. It can also occur in feral animals—among others, game animals—as well as in poultry and other birds.

The causative bacterium lives in the soil and in poorly made silage, and is acquired by ingestion. It is not contagious; over the course of a 30-year observation period of sheep disease in Morocco, the disease only appeared in the late 2000s (decade) when feeding bag-ensiled corn became common. In Iceland, the disease is called "silage sickness".

The disease is sporadic, but can occur as farm outbreaks in ruminants.

Three main forms are usually recognized throughout the affected species:

- encephalitis, the most common form in ruminants

- late abortion

- gastro-intestinal septicemia with liver damage, in monogastric species as well as in preruminant calves and lambs

Listeriosis in animals can sometimes be cured with antibiotics (tetracyclines, chloramphenicol and benzyl penicillin) when diagnosed early. Goats, for example, can be treated upon first noticing the disease's characteristic expression in the animal's face, but is generally fatal.