It is a common condition in weaned calves, young bulls, and heifers. The disease has a chronic course, and the general condition can remain quite good.

There is a swelling of the maxilla and mandible. Fistulisation occurs after some days, leaving a thick, yellowish, non-odorous pus, with mineralised, 2 to 5 mm grains therein.

Later on, a granuloma will form in the place of fistulisation.

The bony lesions are followed by periostitis, with permanent deformation of the facial bones.

The disease is characterised by the formation of painful abscesses in the mouth, lungs, breast, or gastrointestinal tract. Actinomycosis abscesses grow larger as the disease progresses, often over months. In severe cases, they may penetrate the surrounding bone and muscle to the skin, where they break open and leak large amounts of pus, which often contains characteristic granules (sulfur granules) filled with progeny bacteria. These granules are named due to their appearance, but are not actually composed of sulfur.

The "Actinomyces" bacteria that cause lumpy jaw are always present in a healthy cattle's mouth. In order for infection to occur, there must be tissue damage, which is often caused by unusually rough feed that scratches the mouth of the animal or by contact with sharp objects, such as sticks or brambles. Given the mode of infection, lumpy jaw is not contagious.

Mouth actinobacillosis of cattle must be differentiated from actinomycosis that affects bone tissues of the maxilla.

"Actinomycosis" is a rare infectious bacterial disease caused by "Actinomyces" species. About 70% of infections are due to either "Actinomyces israelii" or "A. gerencseriae". Infection can also be caused by other "Actinomyces" species, as well as "Propionibacterium propionicus", which presents similar symptoms. The condition is likely to be polymicrobial aerobic anaerobic infection.

The infection is most commonly caused by abrasions on different soft tissues through which the bacteria, "Actinobacillus lignieresii," enters. These soft tissues include subcutaneous tissues, the tongue, lymph nodes, lungs, and various tissues in the gastrointestinal tract. The injury results in different forms and locations of the disease depending on the location of the tissue. The commensal bacteria is also commonly found in the oral cavity, gastrointestinal tract, and reproductive tract, sometimes resulting in disease. There are generally one or two cases of actinobacillosis per herd found in adult cows, foals or adult horses, and other similar animals.

Affected animals normally have generalised signs such as depression, dullness, weakness and lethargy, pyrexia and weight loss and decreased production. They will also have respiratory signs including bilateral nasal discharge, dyspnoea, tachypnoea and coughing. Occasionally the only sign seen is sudden death.

Typical pathological lesions are very suggestive of the disease - they are localised exclusively to the lung and pleura. Lungs are normally a port wine colour and abundant pleural exudate and pleuritis and adhesions are common. The pleural exudates may have solidified forming a gelatinous covering.

Histological examination of the lung tissues may show acute serofibrinous to chronic fibrino-necrotic pleuropneumonia with neutrophilic inflammation in the alveoli, bronchioles, interstitial septae and subpleural connective tissue.

The several forms of the infection are:

- Skin/subcutaneous tissue disease is a septic phlegmon that develops classically in the hand and forearm after a cat bite. Inflammatory signs are very rapid to develop; in 1 or 2 hours, edema, severe pain, and serosanguineous exudate appear. Fever, moderate or very high, can be seen, along with vomiting, headache, and diarrhea. Lymphangitis is common. Complications are possible, in the form of septic arthritis, osteitis, or evolution to chronicity.

- Sepsis is very rare, but can be as fulminant as septicaemic plague, with high fever, rigors, and vomiting, followed by shock and coagulopathy.

- Pneumonia disease is also rare and appears in patients with some chronic pulmonary pathology. It usually presents as bilateral consolidating pneumonia, sometimes very severe.

- Zoonosis, pasteurellosis can be transmitted to humans through cats.

Other locations are possible, such as septic arthritis, meningitis, and acute endocarditis, but are very rare.

Human’s clinical signs consisted of swelling and eye infections. There were nodules underneath the skin, abscesses or cysts, and lesions running throughout the body. There were papules, plaques and granulomatous damages on the body. In extreme cases there were deep infections within the eyes, bones, heart and central nervous system.

Diagnosis is made with isolation of "Pasteurella multocida" in a normally sterile site (blood, pus, or cerebrospinal fluid).

Green nails may be (1) due to a "Pseudomonas aeruginosa" infection causing a green nail syndrome or (2) the result of copper in tap water.

Contagious caprine pleuropneumonia (CCPP) is a cause of major economic losses to goat producers in Africa, Asia and the Middle East.

Disease is caused by members of the Mycoplasma genus - usually "Mycoplasma capricolum subsp. capricolum" but sometimes by "M. mycoides" subsp. "capri" or "M. mycoides" subsp. "mycoides". It is extremely contagious with very high morbidity and mortality rates, causing an interstitial fibrinous pleuropneumonia in infected goats. Infection is spread by close-contact aerosol, therefore overcrowding and confinement increases disease incidence. Stress factors such as malnutrition and long transport can also predispose animals to disease.

Goats are the only species affected, therefore the disease is not a zoonosis. There is no age breed or sex predilection, but clinical signs are often worse in younger animals.

Phaeohyphomycosis is a heterogeneous group of mycotic infections caused by dematiaceous fungi whose morphologic characteristics in tissue include hyphae, yeast-like cells, or a combination of these. It can be associated an array of darkly-pigmented hyphomycetes including "Alternaria" species"," "Exophiala jeanselmei," and "Rhinocladiella mackenziei".

The term “phaeohyphomycosis” was introduced to determine infections caused by dematiaceous or pigmented filamentous fungi which contain melanin in their cell walls. Phaeohyphomycosis is an uncommon infection, however the number of case reported has been increasing in recent years. The presence of melanin in cell walls may be a virulence factor for the pathogens caused by the fungi. The outcome of antifungal treatment is poor, and mortality is almost 80%. Phaeohyphomycosis has been attributed to more than 100 species and 60 genera of fungi over the past several decades. The pathogens are considered opportunistic. Almost all cases of widely disseminated infection have occurred in immunosuppressed patients.

Common clinical signs of Tyzzer’s Disease include watery diarrhea, depression, emaciation, and a ruffled coat. Other observed clinical signs include melena, depression, lethargy, and decreased temperature. In muskrats, this disease is characterized by extensive hemorrhaging within the lower intestine and abdomen. Due to the fast-acting nature of this disease, infected individuals often do not live long enough to exhibit symptoms. It is not uncommon for an infected animal to die within 1-10 days of disease contraction.

During necropsy, inflammation of the ileum, cecum, and colon are commonly present. Perhaps the most distinctive trait of this disease, however, is the grayish yellow necrotic lesions found on the liver of diseased animals. The number of these spots present can range from one to countless. Occasionally, lesions are discovered in the lower intestinal tract and heart as well. Even with physical signs and symptoms present, a conclusive diagnosis is dependent upon the presence of "C. piliforme" within the liver of the infected animal.

Pseudomonas aeruginosa is a common bacterium that can cause disease in animals, including humans. It is found in soil, water, skin flora, and most man-made environments throughout the world. It thrives not only in normal atmospheres, but also in hypoxic atmospheres, and has, thus, colonized many natural and artificial environments. It uses a wide range of organic material for food; in animals, the versatility enables the organism to infect damaged tissues or those with reduced immunity. The symptoms of such infections are generalized inflammation and sepsis. If such colonizations occur in critical body organs, such as the lungs, the urinary tract, and kidneys, the results can be fatal. Because it thrives on most surfaces, this bacterium is also found on and in medical equipment, including catheters, causing cross-infections in hospitals and clinics. It is implicated in hot-tub rash. It is also able to decompose hydrocarbons and has been used to break down tarballs and oil from oil spills.

In cattle, the main signs of paratuberculosis are diarrhea and wasting. Most cases are seen in 2- to 6-year-old animals. The initial signs can be subtle, and may be limited to weight loss, decreased milk production, or roughening of the hair coat. The diarrhea is usually thick, without blood, mucus, or epithelial debris, and may be intermittent. Several weeks after the onset of diarrhea, a soft swelling may occur under the jaw. Known as "bottle jaw" or intermandibular edema, this symptom is due to protein loss from the bloodstream into the digestive tract. Paratuberculosis is progressive; affected animals become increasingly emaciated and usually die as the result of dehydration and severe cachexia.

Signs are rarely evident until two or more years after the initial infection, which usually occurs shortly after birth. Animals are most susceptible to the infection in the first year of life. Newborns most often become infected by swallowing small amounts of infected manure from the birthing environment or udder of the mother. In addition, newborns may become infected while in the uterus or by swallowing bacteria passed in milk and colostrum. Animals exposed at an older age, or exposed to a very small dose of bacteria at a young age, are not likely to develop clinical disease until they are much older than two years.

The clinical signs are similar in other ruminants. In sheep and goats, the wool or hair is often damaged and easily shed, and diarrhea is uncommon. In deer, paratuberculosis can progress rapidly. Intestinal disease has also been reported in rabbits and nonhuman primates.

Unlike cattle and sheep, infections in deer often present with clinical illness in animals under one year of age.

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.

Cutaneous actinomycosis is a chronic disease that affects the deep subcutaneous tissue of the skin. Caused by an anaerobic, Gram-positive, filamentous type of bacteria in the genus "Actinomyces", invasion of the soft tissue leads to the formation of abnormal channels leading to the skin surface (external sinus tracts) that discharge pale yellow sulfur granules.

This disease is uncommon, and has non-specific clinical features, making it difficult to diagnose.

Cervicofacial, pulmonary/thoracic and gastrointestinal forms exist, yet cervicofacial disease accounts for two-thirds of reported infections.

Paratuberculosis or Johne's disease is a contagious, chronic and sometimes fatal infection that primarily affects the small intestine of ruminants. It is caused by the bacterium "Mycobacterium avium" subspecies "paratuberculosis". Infections normally affect ruminants (mammals that have four compartments of their stomachs, of which the rumen is one), but have also been seen in a variety of nonruminant species, including rabbits, foxes, and birds. Horses, dogs, and nonhuman primates have been infected experimentally. Paratuberculosis is found worldwide, with some states in Australia (where it is usually called bovine Johne's disease or BJD) as the only areas proven to be free of the disease.

Some sources define "paratuberculosis" by the lack of "Mycobacterium tuberculosis", rather than the presence of any specific infectious agent, leaving ambiguous the appropriateness of the term to describe Buruli ulcer or Lady Windermere syndrome.

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.

Tyzzer’s disease is an acute epizootic bacterial disease found in rodents, rabbits, dogs, cats, birds, pandas, deer, foals, cattle, and other mammals including gerbils. It is caused by the spore-forming bacterium "Clostridium piliforme", formerly known as "Bacillus piliformis". It is an infectious disease characterized by necrotic lesions on the liver, is usually fatal, and is present worldwide. Animals with the disease become infected through oral ingestion of the bacterial spores and usually die within a matter of days. Animals most commonly affected include young, stressed animals in laboratory environments, such as immature rodents and rabbits. Most commonly affected wild animals include muskrats "(Ondatra zibethicus)" and occasionally cottontail rabbits "(Lepus sylvaticus)". Even today, much remains unknown about Tyzzer’s disease, including how and why it occurs.

Besnoitiosis is "a protozoan disease of the skin, subcutis, blood vessels, mucous membranes, and other tissues" of animals. It "is endemic in tropical and sub-tropical regions with high infection rate but low mortality"; however, it is rare in other regions.

The causative organisms of the cutaneous disease, and the affected animals include:

- "Besnoitia besnoiti" in cattle (swelling of the lymph nodes, subcutaneous swellings, diarrhea, abortion and infertility)

- "Besnoitia bennetti" in horses and donkeys (characterized by a widespread, serious dermatitis)

- "Besnoitia jellisoni" and "B. wallacei" in rodents

- "Besnoitia tarandi" in reindeer and caribou

- "Besnoitia darlingi" in lizards, opossums, and snakes

- "Besnoitia sauriana" in lizards

- Viscerotropic strains of "B.besnoiti" in African antelope

- An unidentified "Besnoitia" species in goats in Iran, New Zealand, and Kenya

The diagnosis is aided by obtaining a history of the circumstances surrounding the bite. The time the bite was experienced, the location of the bite, and examination of the bite is noted. The person may have drainage from the site of the bite. They may also be febrile. Swelling may also occur. Because the wound from the bite may have healed over the punctures, the wound it may be opened and explored. The site is anesthetized prior to exploration of the wound for is examined for damage. Neurovascular status is assessed. Immune status may determine treatment as does

the presence of transplanted tissue or organs, rheumatic disease, diabetes, HIV/AIDS and sickle cell disease.

Swollen glands (lymph nodes) and red streaks radiating upward may be evident.

The diagnosis of a cat with rabies is evident by observing the cat. Cats with rabies may also appear restless, pant, and attack other animals, people, or objects. Animals with rabies typically die within a few days of appearing sick. Vaccination of the cat can prevent rabies being transmitted by the cat through a bite. If the cat is suspected of being infected with rabies, the person begins treatment with rabies vaccine.

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.

An ameboma, also known as an amebic granuloma, is a rare complication of "Entamoeba histolytica" infection, where in response to the infecting amoeba there is formation of annular colonic granulation, which results in a large local lesion of the bowel.