Definite diagnosis of brucellosis requires the isolation of the organism from the blood, body fluids, or tissues, but serological methods may be the only tests available in many settings. Positive blood culture yield ranges between 40% and 70% and is less commonly positive for "B. abortus" than "B. melitensis" or "B. suis". Identification of specific antibodies against bacterial lipopolysaccharide and other antigens can be detected by the standard agglutination test (SAT), rose Bengal, 2-mercaptoethanol (2-ME), antihuman globulin (Coombs’) and indirect enzymelinked immunosorbent assay (ELISA). SAT is the most commonly used serology in endemic areas. An agglutination titre greater than 1:160 is considered significant in nonendemic areas and greater than 1:320 in endemic areas. Due to the similarity of the O polysaccharide of "Brucella" to that of various other Gram-negative bacteria (e.g. "Francisella tularensis", "Escherichia coli", "Salmonella urbana", "Yersinia enterocolitica", "Vibrio cholerae", and "Stenotrophomonas maltophilia") the appearance of cross-reactions of class M immunoglobulins may occur. The inability to diagnose "B. canis" by SAT due to lack of cross-reaction is another drawback. False-negative SAT may be caused by the presence of blocking antibodies (the prozone phenomenon) in the α2-globulin (IgA) and in the α-globulin (IgG) fractions. Dipstick assays are new and promising, based on the binding of "Brucella" IgM antibodies, and found to be simple, accurate, and rapid. ELISA typically uses cytoplasmic proteins as antigens. It measures IgM, IgG, and IgA with better sensitivity and specificity than the SAT in most recent comparative studies. The commercial Brucellacapt test, a single-step immunocapture assay for the detection of total anti-"Brucella" antibodies, is an increasingly used adjunctive test when resources permit. PCR is fast and should be specific. Many varieties of PCR have been developed (e.g. nested PCR, realtime PCR and PCR-ELISA) and found to have superior specificity and sensitivity in detecting both primary infection and relapse after treatment. Unfortunately, these have yet to be standardized for routine use, and some centres have reported persistent PCR positivity after clinically successful treatment, fuelling the controversy about the existence of prolonged chronic brucellosis. Other laboratory findings include normal peripheral white cell count, and occasional leucopenia with relative lymphocytosis. The serum biochemical profiles are commonly normal.

According to a study published in 2002, an estimated 10–13% of farm animals are infected with "Brucella" species. Annual losses from the disease were calculated to be around 60 million dollars. Since 1932, government agencies have undertaken efforts to contain the disease. Currently, all cattle of ages 3–8 months is required to be given the "Brucella abortus" strain 19 vaccine.

Because the risk of meningococcal disease is increased among USA's military recruits, all military recruits routinely receive primary immunization against the disease.

Meningitis A,C,Y and W-135 vaccines can be used for large-scale vaccination programs when an outbreak of meningococcal disease occurs in Africa and other regions of the world. Whenever sporadic or cluster cases or outbreaks of meningococcal disease occur in the US, chemoprophylaxis is the principal means of preventing secondary cases in household and other close contacts of individuals with invasive disease. Meningitis A,C,Y and W-135 vaccines rarely may be used as an adjunct to chemoprophylaxis,1 but only in situations where there is an ongoing risk of exposure (e.g., when cluster cases or outbreaks occur) and when a serogroup contained in the vaccine is involved.

It is important that clinicians promptly report all cases of suspected or confirmed meningococcal disease to local public health authorities and that the serogroup of the meningococcal strain involved be identified. The effectiveness of mass vaccination programs depends on early and accurate recognition of outbreaks. When a suspected outbreak of meningococcal disease occurs, public health authorities will then determine whether mass vaccinations (with or without mass chemoprophylaxis) is indicated and delineate the target population to be vaccinated based on risk assessment.

It is done through isolation of a bacteria from chickens suspected to have history of coryza and clinical finds from infected chickens also is used in the disease diagnosis. Polymerase chain reaction is a reliable means of diagnosis of the disease

Infections are treated with antibiotics, particularly doxycycline, and the acute symptoms appear to respond to these drugs.

There is no vaccine for SVD. Prevention measures are similar to those for foot-and-mouth disease: controlling animals imported from infected areas, and sanitary disposal of garbage from international aircraft and ships, and thorough cooking of garbage. Infected animals should be placed in strict quarantine. Eradication measures for the disease include quarantining infected areas, depopulation and disposal of infected and contact pigs, and cleaning and disinfecting

contaminated premises.

No serious long-term effects are known for this disease, but preliminary evidence suggests, if such symptoms do occur, they are less severe than those associated with Lyme disease.

Prevention is through use of Stock coryza-free birds. In other areas culling of the whole flock is a good means of the disease control. Bacterin also is used at a dose of two to reduce brutality of the disease. Precise exposure has also has been used but it should be done with care. Vaccination of the chicks is done in areas with high disease occurrence. Treatment is done by using antibiotics such as erythromycin, Dihydrostreptomycin, Streptomycin sulphonamides, tylosin and Flouroquinolones .

Diagnosis of lymphoid tumors in poultry is complicated due to multiple etiological agents capable of causing very similar tumors. It is not uncommon that more than one avian tumor virus can be present in a chicken, thus one must consider both the diagnosis of the disease/tumors (pathological diagnosis) and of the virus (etiological diagnosis). A step-wise process has been proposed for diagnosis of Marek’s disease which includes (1) history, epidemiology, clinical observations and gross necropsy, (2) characteristics of the tumor cell, and (3) virological characteristics

The demonstration of peripheral nerve enlargement along with suggestive clinical signs in a bird that is around three to four months old (with or without visceral tumors) is highly suggestive of Marek's disease. Histological examination of nerves reveals infiltration of pleomorphic neoplastic and inflammatory lymphocytes. Peripheral neuropathy should also be considered as a principal rule-out in young chickens with paralysis and nerve enlargement without visceral tumors, especially in nerves with interneuritic edema and infiltration of plasma cells.

The presence of nodules on the internal organs may also suggest Marek's disease, but further testing is required for confirmation. This is done through histological demonstration of lymphomatous infiltration into the affected tissue. A range of leukocytes can be involved, including lymphocytic cell lines such as large lymphocyte, lymphoblast, primitive reticular cells, and occasional plasma cells, as well as macrophage and plasma cells. The T cells are involved in the malignancy, showing neoplastic changes with evidence of mitosis. The lymphomatous infiltrates need to be differentiated from other conditions that affect poultry including lymphoid leukosis and reticuloendotheliosis, as well as an inflammatory event associated with hyperplastic changes of the affected tissue.

Key clinical signs as well as gross and microscopic features that are most useful for differentiating Marek’s disease from lymphoid leukosis and reticuloendotheliosis include (1) Age: MD can affect birds at any age, including 5% in unvaccinated flocks; (4) Potential nerve enlargement; (5) Interfollicular tumors in the bursa of Fabricius; (6) CNS involvement; (7) Lymphoid proliferation in skin and feather follicles; (8) Pleomorphic lymphoid cells in nerves and tumors; and (9) T-cell lymphomas.

In addition to gross pathology and histology, other advanced procedures used for a definitive diagnosis of Marek’s disease include immunohistochemistry to identify cell type and virus-specific antigens, standard and quantitative PCR for identification of the virus, virus isolation to confirm infections, and serology to confirm/exclude infections.

The World Organisation for Animal Health (OIE) reference laboratories for Marek’s disease include the Pirbright Institute, UK and the USDA Avian Disease and Oncology Laboratory, USA.

Swine vesicular disease is most commonly brought into a herd by the introduction of a subclinically infected pig.

The disease can be transmitted in feed containing infected meat scraps, or by direct contact with infected feces (such as in an improperly cleaned truck).

Pacheco's disease is an acute and often lethal infectious disease in psittacine birds. The disease is caused by a group of herpesviruses, "Psittacid herpesvirus 1" (PsHV-1), which consists of four genotypes. Birds which do not succumb to Pacheco's disease after infection with the virus become asymptomatic carriers that act as reservoirs of the infection. These persistently infected birds, often Macaws, Amazon parrots and some species of conures, shed the virus in feces and in respiratory and oral secretions. Outbreaks can occur when stress causes healthy birds who carry the virus to shed it. Birds generally become infected after ingesting the virus in contaminated material, and show signs of the disease within several weeks.

The main sign of Pacheco's disease is sudden death, sometimes preceded by a short, severe illness. If a bird survives Pacheco's disease following infection with PsHV-1 genotypes 1, 2 or 3, it may later develop internal papilloma disease in the gastrointestinal tract.

Susceptible parrot species include the African gray parrot, and cockatoo. Native Australian birds, such as the eclectus parrot, Bourke's parrot, and budgerigar are susceptible to Pacheco's disease, although the disease itself has not been found in Australia.

Vaccination is the only known method to prevent the development of tumors when chickens are infected with the virus. However, administration of vaccines does not prevent transmission of the virus, i.e., the vaccine is not sterilizing. However, it does reduce the amount of virus shed in the dander, hence reduces horizontal spread of the disease. Marek's disease does not spread vertically. The vaccine was introduced in 1970 and the scientist credited with its development is Dr. Ben Roy Burmester and Dr. Frank J Siccardi. Before that, Marek's disease caused substantial revenue loss in the poultry industries of the United States and the United Kingdom. The vaccine can be administered to one-day-old chicks through subcutaneous inoculation or by "in ovo" vaccination when the eggs are transferred from the incubator to the hatcher. "In ovo" vaccination is the preferred method, as it does not require handling of the chicks and can be done rapidly by automated methods. Immunity develops within two weeks.

The vaccine originally contained the antigenically similar turkey herpesvirus, which is serotype 3 of MDV. However, because vaccination does not prevent infection with the virus, the Marek's disease virus has evolved increased virulence and resistance to this vaccine. As a result, current vaccines use a combination of vaccines consisting of HVT and gallid herpesvirus type 3 or an attenuated MDV strain, CVI988-Rispens (ATCvet code: ).

In laboratory animals, prevention includes a low-stress environment, an adequate amount of nutritional feed, and appropriate sanitation measurements. Because animals likely ingest bacterial spores from contaminated bedding and feed, regular cleaning is a helpful method of prevention. No prevention methods are currently available for wild animal populations.

Currently, antibiotic drugs such as penicillin or tetracycline are the only effective methods for disease treatment. Within wild populations, disease control consists of reducing the amount of bacterial spores present in the environment. This can be done by removing contaminated carcasses and scat.

Pacheco's disease is an eponymously named disease; it is named after the Brazilian veterinarian, Genesio Pacheco, who first came across the disease in 1929, in an outbreak affecting the turquoise-fronted amazon parrot, "Amazona aestiva". Initially, Pacheco's disease was thought to be a manifestation of avian psittacosis. The causative agent of the disease, a herpesvirus, was not identified until 1975.

Pogosta disease is a viral disease, established to be identical with other diseases, Karelian fever and Ockelbo disease. The names are derived from the words Pogosta, Karelia and Ockelbo, respectively.

The symptoms of the disease include usually rash, as well as mild fever and other flu-like symptoms; in most cases the symptoms last less than 5 days. However, in some cases, the patients develop a painful arthritis. There are no known chemical agents available to treat the disease.

It has long been suspected that the disease is caused by a Sindbis-like virus, a positive-stranded RNA virus belonging to the Alphavirus genus and family Togaviridae. In 2002 a strain of Sindbis was isolated from patients during an outbreak of the Pogosta disease in Finland, confirming the hypothesis.

This disease is mainly found in the Eastern parts of Finland; a typical Pogosta disease patient is a middle-aged person who has been infected through a mosquito bite while picking berries in the autumn. The prevalence of the disease is about 100 diagnosed cases every year, with larger outbreaks occurring in 7-year intervals.

Chronic Lyme disease is a generally unrecognised diagnosis that encompasses "a broad array of illnesses or symptom complexes for which there is no reproducible or convincing scientific evidence of any relationship to "B. burgdorferi" infection." There is no clinical evidence that "chronic" Lyme disease is caused by a persistent infection. It is distinct from post-treatment Lyme disease syndrome, a set of lingering symptoms which may persist after successful treatment of infection with Lyme spirochetes. The symptoms of "chronic Lyme" are generic and non-specific "symptoms of life".

A number of alternative treatments are promoted for "chronic Lyme disease", of which possibly the most controversial and harmful is long-term antibiotic therapy, particularly intravenous antibiotics. Most medical authorities advise against long-term antibiotic treatment for Lyme disease, though they agree that some patients do experience lingering symptoms. Following disciplinary proceedings by State medical licensing boards in the United States, a subculture of "Lyme literate" physicians has successfully lobbied for specific legal protections, exempting them from the standard of care and Infectious Diseases Society of America treatment guidelines. This "troubling" political interference in medical care has been criticised as an example of "legislative alchemy", the process whereby pseudomedicine is legislated into practice.

Common clinical signs and symptoms of Whipple's disease include diarrhea, steatorrhea, abdominal pain, weight loss, migratory arthropathy, fever, and neurological symptoms. Weight loss and diarrhea are the most common symptoms that lead to identification of the process, but may be preceded by chronic, unexplained, relapsing episodes of non-destructive seronegative arthritis, often of large joints.

Diagnosis is made by biopsy, usually by duodenal endoscopy, which reveals PAS-positive macrophages in the lamina propria containing non-acid-fast gram-positive bacilli. Immunohistochemical staining for antibodies against "T. whipplei" has been used to detect the organism in a variety of tissues, and a PCR-based assay is also available. PCR can be confirmatory if performed on blood, vitreous fluid, synovial fluid, heart valves, or cerebrospinal fluid. PCR of saliva, gastric or intestinal fluid, and stool specimens is highly sensitive, but not specific enough, indicating that healthy individuals can also harbor the causative bacterium without the manifestation of Whipple's disease, but that a negative PCR is most likely indicative of a healthy individual.

Endoscopy of the duodenum and jejunum can reveal pale yellow shaggy mucosa with erythematous eroded patches in patients with classic intestinal Whipple's disease, and small bowel X-rays may show some thickened folds. Other pathological findings may include enlarged mesenteric lymph nodes, hypercellularity of lamina propria with "foamy macrophages", and a concurrent decreased number of lymphocytes and plasma cells, per high power field view of the biopsy.

A D-Xylose test can be performed, which is where the patient will consume 4.5g of D-xylose, a sugar, by mouth. The urine excretion of D-Xylose is then measured after 5 hours. The majority of D-Xylose is absorbed normally, and should be found in the urine. If the D-Xylose is found to be low in the urine, this suggests an intestinal malabsorption problem such as bacterial overgrowth of the proximal small intestine, Whipple's Disease, or an autoimmune with diseases such as Celiac's Disease (allergy to gluten) or Crohn's Disease (autoimmune disease affecting the small intestine). With empiric antibiotic treatment after an initial positive D-Xylose test, and if a follow-up D-Xylose test is positive (decreased urine excretion) after antibiotic therapy, then this would signify it is not bacterial overgrowth of the proximal small intestine. Since Whipple's disease is so rare, a follow-up positive D-Xylose test more likely indicates a non-infectious etiology and more likely an autoimmune etiology. Clinical correlation is recommended to rule out Whipple's disease.

The term "chronic Lyme disease" is often applied to several different sets of people. One usage refers to people suffering from the symptoms of untreated and disseminated late-stage Lyme disease: arthritis, peripheral neuropathy and/or encephalomyelitis. The term is also applied to people who have had the disease in the past and some symptoms remain after antibiotic treatment, which is also called post-Lyme disease syndrome. A third and controversial use of the term applies to patients with nonspecific symptoms, such as fatigue, who show no objective evidence they have been infected with Lyme disease in the past, since the standard diagnostic tests for infection are negative.

The Centers for Disease Control and Prevention state that some people after a "course of antibiotics will have lingering symptoms of fatigue, pain, or joint and muscle aches. In some cases, these can last for more than 6 months. Although often called 'chronic Lyme disease', this condition is properly known as 'post-treatment Lyme disease syndrome' (PTLDS)". This is estimated to occur in less than 5% of people who had Lyme disease and were treated.

While it is undisputed people can have severe symptoms, the cause and appropriate treatment are controversial. The symptoms may represent "for all intents and purposes" fibromyalgia or chronic fatigue syndrome. A few doctors attribute these symptoms to persistent infection with "Borrelia", or co-infections with other tick-borne pathogens, such as "Ehrlichia" and "Babesia". Other doctors believe that the initial infection may cause an autoimmune reaction that continues to cause serious symptoms even after the bacteria have been eliminated by antibiotics. A review looked at several animal studies that found persistence of live but disabled spirochetes following treatment of "B. burgdorferi" infection with antibiotics. The authors noted that none of the lingering spirochetes were associated with inflamed tissues and criticized the studies for not considering adequately the different pharmacodynamics and pharmacokinetics of the antibiotics used to treat the animals in the trials versus what would be expected to be used to treat humans. The authors concluded, "There is no scientific evidence to support the hypothesis that such spirochetes, should they exist in humans, are the cause of post-Lyme disease syndrome."

Major US medical authorities, including the Infectious Diseases Society of America, the American Academy of Neurology, and the National Institutes of Health, have stated there is no convincing evidence that "Borrelia" is involved in the various symptoms classed as chronic Lyme disease, and advise against long-term antibiotic treatment as ineffective and possibly harmful. Prolonged antibiotic therapy presents significant risks and can have dangerous side effects. Randomized placebo-controlled studies have shown that antibiotics offer no sustained benefit in people with "chronic Lyme"; with evidence of both placebo effects and significant adverse effects from such treatment. An advocacy group called the International Lyme And Associated Diseases Society (ILADS) argues the persistence of "B. burgdorferi" may be responsible for manifestations of late Lyme disease symptoms. It has questioned the generalizability and reliability of some of the above trials and the reliability of the current diagnostic tests.

Treatment is with penicillin, ampicillin, tetracycline, or co-trimoxazole for one to two years. Any treatment lasting less than a year has an approximate relapse rate of 40%. Recent expert opinion is that Whipple's disease should be treated with doxycycline with hydroxychloroquine for 12 to 18 months. Sulfonamides (sulfadiazine or sulfamethoxazole) may be added for treatment of neurological symptoms.

Bright's disease was historically 'treated' with warm baths, blood-letting, squill, digitalis, mercuric compounds, opium, diuretics, laxatives, and dietary therapy, including abstinence from alcoholic drinks, cheese and red meat. Arnold Ehret was diagnosed with Bright's disease and pronounced incurable by 24 of Europe's most respected doctors; he designed "The Mucusless Diet Healing System", which apparently cured his illness. William Howard Hay, MD had the illness and, it is claimed, cured himself using the Hay diet.

The diagnosis is clinical, not based upon serology. At least seven sets of diagnostic criteria have been devised, however the Yamaguchi criteria have the highest sensitivity. Diagnosis requires at least five features, with at least two of these being major diagnostic criteria.

The symptoms and signs of Bright's disease were first described in 1827 by the English physician Richard Bright, after whom the disease was named. In his "Reports of Medical Cases", he described 25 cases of dropsy (edema) which he attributed to kidney disease. Symptoms and signs included: inflammation of serous membranes, hemorrhages, apoplexy, convulsions, blindness and coma. Many of these cases were found to have albumin in their urine (detected by the spoon and candle-heat coagulation), and showed striking morbid changes of the kidneys at autopsy. The triad of dropsy, albumin in the urine and kidney disease came to be regarded as characteristic of Bright's disease. Subsequent work by Bright and others indicated an association with cardiac hypertrophy, which was attributed by Bright to stimulation of the heart. Subsequent work by Mahomed showed that a rise in blood pressure could precede the appearance of albumin in the urine, and the rise in blood pressure and increased resistance to flow was believed to explain the cardiac hypertrophy.

It is now known that Bright's disease is due to a wide range of diverse kidney diseases; thus, the term "Bright's disease" is retained strictly for historical application. The disease was diagnosed frequently in patients with diabetes; at least some of these cases would probably correspond to a modern diagnosis of diabetic nephropathy.

The twins require the use of wheelchairs for mobility and are unable to speak without the assistance of electronic speaking aids. They experience persistent and painful muscle spasms which are worsened by emotional distress. They are currently living with their parents, with the assistance of hospice workers. Doctors continue to administer tests to the twins in search of a treatment.