Diagnosis is made by taking samples for bacterial culture from all accessible sites. In mares, this includes the endometrium, cervix, clitoral fossa and sinuses. In stallions, samples are taken from the skin folds of the prepuce, urethral fossa, urethra, and the pre-ejaculatory fluid. Samples are refrigerated and transported to an approved testing laboratory within 48 hours of collection.

Blood tests for mares are available for detecting antibodies to "Taylorella equigenitalis". Blood tests are not possible for stallions. These tests become positive 10 or more days after infection. If positive, they only indicate that the mare has had the disease in the past, and do not indicate whether the mare is a carrier now.

"Taylorella equigenitalis" is susceptible to most antibiotics, although the carrier state in mares is difficult to eliminate. Most mares with acute endometritis recover spontaneously. Recommended therapy is to infuse the uterus with an antibiotic such as penicillin, cleansing the clitoral area with 2% chlorhexidine solution and then applying chlorhexidine or nitrofurazone ointment to the clitoral fossa and sinuses. The entire treatment is repeated daily for five days.

It is relatively easy to eliminate the carrier state in stallions using local disinfectant. With the stallion's penis dropped and the glans extended from the foreskin, the shaft of the penis, including the folds of the prepuce and the urethral fossa, should be cleansed daily for five days with a 2% chlorhexidine solution. After drying, nitrofurazone cream is applied to these areas.

Most often the diagnosis is made clinically. Dark field microscopy of samples taken from early lesions (particularly ulcerative lesions) may show the responsible organism. Blood tests such as VDRL, Rapid Plasma Reagin (RPR) and TPHA will also be positive, but there are no current blood tests which distinguish among the four treponematoses.

The Coggins test (agar immunodiffusion) is a sensitive diagnostic test for equine infectious anemia developed by Dr. Leroy Coggins in the 1970s.

Currently, the US does not have an eradication program due to the low rate of incidence. However, many states require a negative Coggins test for interstate travel. In addition, most horse shows and events require a negative Coggins test. Most countries require a negative test result before allowing an imported horse into the country.

Horse owners should verify that all the horses at a breeding farm and or boarding facility have a negative Coggins test before using the services of the facility. A Coggins test should be done on an annual basis. Tests every 6 months are recommended if there is increased traveling.

Specific age groups, persons who participate in risky sexual behavior, or those have certain health conditions may require screening. The CDC recommends that sexually active women under the age of 25 and those over 25 at risk should be screened for chlamydia and gonorrhea yearly. Appropriate times for screening are during regular pelvic examinations and preconception evaluations. Nucleic acid amplification tests are the recommended method of diagnosis for gonorrhea and chlamydia. This can be done on either urine in both men and women, vaginal or cervical swabs in women, or urethral swabs in men. Screening can be performed:

- to assess the presence of infection and prevent tubal infertility in women

- during the initial evaluation before infertility treatment

- to identify HIV infection

- for men who have sex with men

- for those who may have been exposed to hepatitis C

- for HCV

There are several methods to diagnose meningeal syphilis. One of the most common ways include visualizing the organisms by immunofluorescence and dark field microscopy. Dark field microscopy initially had the finding that the spirochete has a corkscrew appearance and that it is spirillar and gram (-) bacteria. Another method would also be through the screening test and serology. Serology includes two types of antibody test: Nontreponemal antibody test and Treponemal antibody test (specific test). The Nontreponemal antibody test screens with VDRL (Venereal Disease Research Lab) and RPR (Rapid Plasma Reagin). The Treponemal antibody test (specific test) confirms with FTA-ABS (Fluorescent treponemal antibody-absorption). Brain imaging and MRI scans may be used when diagnosing patients; however, they do not prove to be as effective as specific tests. Specific tests for treponemal antibody are typically more expensive because the earliest anitbodies bind to spirochetes. These tests are usually more specific and remain positive in patients with other treponemal diseases.

It is currently thought that it may be possible to eradicate yaws although it is not certain that humans are the only reservoir of infection. A single injection of long-acting penicillin or other beta lactam antibiotic cures the disease and is widely available; and the disease is believed to be highly localised.

In April 2012, WHO initiated a new global campaign for the eradication of yaws, which has been on the WHO eradication list since 2011. According to the official roadmap, elimination should be achieved by 2020.

Prior to the most recent WHO campaign, India launched its own national yaws elimination campaign which appears to have been successful.

Certification for disease-free status requires an absence of the disease for at least five years. In India this happened on 19 September 2011. In 1996 there were 3,571 yaws cases in India; in 1997 after a serious elimination effort began the number of cases fell to 735. By 2003 the number of cases was 46. The last clinical case in India was reported in 2003 and the last latent case in 2006. India is a country where yaws is now considered to have been eliminated

In March 2013, WHO convened a new meeting of yaws experts in Geneva to further discuss the strategy of the new eradication campaign. The meeting was significant, and representatives of most countries where yaws is endemic attended and described the epidemiological situation at the national level. The disease is currently known to be present in Indonesia and Timor-Leste in South-East Asia; Papua New Guinea, the Solomon Islands and Vanuatu in the Pacific region; and Benin, Cameroon, Central African Republic, Congo, Côte d'Ivoire, Democratic Republic of Congo, Ghana and Togo in Africa. As reported at the meeting, in several such countries, mapping of the disease is still patchy and will need to be completed before any serious eradication effort could be enforced.

Testing may be for a single infection, or consist of a number of tests for a range of STIs, including tests for syphilis, trichomonas, gonorrhea, chlamydia, herpes, hepatitis and HIV. No procedure tests for all infectious agents.

STI tests may be used for a number of reasons:

- as a diagnostic test to determine the cause of symptoms or illness

- as a screening test to detect asymptomatic or presymptomatic infections

- as a check that prospective sexual partners are free of disease before they engage in sex without safer sex precautions (for example, when starting a long term mutually monogamous sexual relationship, in fluid bonding, or for procreation).

- as a check prior to or during pregnancy, to prevent harm to the baby

- as a check after birth, to check that the baby has not caught an STI from the mother

- to prevent the use of infected donated blood or organs

- as part of the process of contact tracing from a known infected individual

- as part of mass epidemiological surveillance

Early identification and treatment results in less chance to spread disease, and for some conditions may improve the outcomes of treatment. There is often a window period after initial infection during which an STI test will be negative. During this period, the infection may be transmissible. The duration of this period varies depending on the infection and the test. Diagnosis may also be delayed by reluctance of the infected person to seek a medical professional. One report indicated that people turn to the Internet rather than to a medical professional for information on STIs to a higher degree than for other sexual problems.

The most popular treatment forms for any type of syphilis uses penicillin, which has been an effective treatment used since the 1940s.

Other forms also include Benzathine penicillin, which is usually used for primary and secondary syphilis (it has no resistance to penicillin however). Benzathine penicillin is used for long acting form, and if conditions worsen, penicillin G is used for late syphilis.

A vaccine is available in the UK and Europe, however in laboratory tests it is not possible to distinguish between antibodies produced as a result of vaccination and those produced in response to infection with the virus. Management also plays an important part in the prevention of EVA.

This disease affects the external genitalia, and is caused by equine herpesvirus 3. This disease remains with the horse for all its life. Equine coital exanthema is believed to only be transmitted during the acute phase of the disease through serous fluid from the blisters during sexual intercourse, and via breeding tools, handlers, etc.

Clinical signs include cute small lesions, no bigger than 2 mm in diameter around the vulva in mares, and on the sheath in stallions. The small bumps blister and then rupture, leaving raw, ulcerated, painful sores. While the majority of the symptoms are external, the presence of the virus can cause small and large plaque variants in tissues.

Diagnosis of PHF is accomplished by measuring antibody titers or PCR testing to look for the bacterium in the blood and feces. However, most veterinarians opt to initiate treatment right away, as the disease can progress quite quickly. Veterinarians may also run complete blood counts and chemistry and electrolyte panels to determine the course of care. Radiographs may be taken to track the progress of laminitic horses.

Only specialized laboratories can adequately diagnose "Babesia" infection in humans, so "Babesia" infections are considered highly under-reported. It develops in patients who live in or travel to an endemic area or receive a contaminated blood transfusion within the preceding 9 weeks, so this aspect of the medical history is vital. Babesiosis may be suspected when a person with such an exposure history develops persistent fevers and hemolytic anemia. The definitive diagnostic test is the identification of parasites on a Giemsa-stained thin-film blood smear.

So-called "Maltese cross formations" on the blood film are diagnostic (pathognomonic) of babesiosis, since they are not seen in malaria, the primary differential diagnosis. Careful examination of multiple smears may be necessary, since "Babesia" may infect less than 1% of circulating red blood cells, thus be easily overlooked.

Serologic testing for antibodies against "Babesia" (both IgG and IgM) can detect low-level infection in cases with a high clinical suspicion, but negative blood film examinations. Serology is also useful for differentiating babesiosis from malaria in cases where people are at risk for both infections. Since detectable antibody responses require about a week after infection to develop, serologic testing may be falsely negative early in the disease course.

A polymerase chain reaction (PCR) test has been developed for the detection of "Babesia" from the peripheral blood. PCR may be at least as sensitive and specific as blood-film examination in diagnosing babesiosis, though it is also significantly more expensive. Most often, PCR testing is used in conjunction with blood film examination and possibly serologic testing.

Other laboratory findings include decreased numbers of red blood cells and platelets on complete blood count.

In animals, babesiosis is suspected by observation of clinical signs (hemoglobinuria and anemia) in animals in endemic areas. Diagnosis is confirmed by observation of merozoites on thin film blood smear examined at maximum magnification under oil using Romonovski stains (methylene blue and eosin). This is a routine part of the veterinary examination of dogs and ruminants in regions where babesiosis is endemic.

"Babesia canis" and "B. bigemina" are "large "Babesia" species" that form paired merozoites in the erythrocytes, commonly described as resembling "two pears hanging together", rather than the "Maltese cross" of the "small "Babesia" species". Their merozoites are around twice the size of small ones.

Cerebral babesiosis is suspected "in vivo" when neurological signs (often severe) are seen in cattle that are positive for "B. bovis" on blood smear, but this has yet to be proven scientifically. Outspoken red discoloration of the grey matter "post mortem" further strengthens suspicion of cerebral babesiosis. Diagnosis is confirmed "post mortem" by observation of "Babesia"-infected erythrocytes sludged in the cerebral cortical capillaries in a brain smear.

Because of the variability of symptoms, diagnosis is by laboratory testing. Blood samples, nasal swabs and semen can be used for isolation of the virus, detection of the viral RNA by polymerase chain reaction (PCR), and detection of antibodies by ELISA and virus neutralisation tests.

The acute symptoms of contagious equine metritis include acyine inflammation of the uterus, an obvious thick, milky, mucous vulvar discharge 10 to 14 days after a live covering by a stallion. Chronic symptoms include milder uterine inflammation that will cause less obvious vulvar discharge, and then the infection may be more difficult to eliminate. Carrier mares can occur once the bacteria become stable within the reproductive tract. These mares can be asymptomatic for months and still remain infectious.

The first case of CEM was diagnosed in England in 1977. It has infected horses in 26 countries:

Austria, Belgium, Bosnia-Herzegovina, Croatia, the Czech Republic, Denmark, Finland, France, Germany, Great Britiain, Greece, Guinea-Bissau, Ireland, Italy, Japan, Luxembourg, the Republic of Macedonia, Montenegro, the Netherlands, Norway, Serbis, the Slovak Republic, Slovenia, Sweden, Switzerland, and the United States.

A vaccine is available, called "Chinese Live Attenuated EIA vaccine", developed in China and widely used there since 1983. Another attenuated live virus vaccine is in development in the United States.

Reuse of syringes and needles is a risk factor for transfer of the disease. Currently in the United States, all horses that test positive must be reported to federal authorities by the testing laboratory. EIA-positive horses are infected for life. Options for the horse include sending the horse to a recognized research facility, branding the horse and quarantining it at least 200 yards from other horses for the rest of its life, and euthanizing the horse. Very few quarantine facilities exist, which usually leads to the option of euthanizing the horse. The Florida Research Institute for Equine Nurturing, Development and Safety (a.k.a. F.R.I.E.N.D.S.) is one of the largest such quarantine facilities and is located in south Florida.

The horse industry and the veterinary industry strongly suggest that the risks posed by infected horses, even if they are not showing any clinical signs, are enough of a reason to impose such stringent rules. The precise impacts of the disease on the horse industry are unknown.

It is treatable with penicillin or other antibiotics, resulting in a complete recovery.

Laboratory blood tests can identify evidence of chikungunya or other similar viruses such as dengue and Zika. Blood test may confirm the presence of IgM and IgG anti-chikungunya antibodies. IgM antibodies are highest 3 to 5 weeks after the beginning of symptoms and will continue be present for about 2 months.

A Zika virus infection might be suspected if symptoms are present and an individual has traveled to an area with known Zika virus transmission. Zika virus can only be confirmed by a laboratory test of body fluids, such as urine or saliva, or by blood test.

While a vaccine is available for PHF, it does not cover all strains of the bacterium, and recent vaccine failures seem to be on the rise. Additionally, the vaccine usually produces a very weak immune response, which may only lessen the severity of the disease rather than prevent it. The vaccine is administered twice a year, in early spring and in early summer, with the first one inoculation given before the mayflies emerge and the second administered as a booster.

Some veterinarians have started making recommendations for farm management to try to prevent this disease:

- Maintaining riparian barriers along bodies of water may encourage aquatic insects to stay near their places of origin

- Turning off outside lights around the barn will prevent insects from being attracted

- Cleaning water buckets and feed areas frequently and keeping food covered will reduce the chance that the horse will accidentally ingest infected insects

Bejel, or endemic syphilis, is a chronic skin and tissue disease caused by infection by the "endemicum" subspecies of the spirochete "Treponema pallidum".

Bejel is also known by a variety of other names, including belesh, dichuchwa, endemic syphilis, nonvenereal syphilis, frenga, njovera, skerljevo, siti, or treponematosis-bejel type.

Treatment of asymptomatic carriers should be considered if parasites are still detected after 3 months. In mild-to-moderate babesiosis, the treatment of choice is a combination of atovaquone and azithromycin. This regimen is preferred to clindamycin and quinine because side effects are fewer. The standard course is 7 to 10 days, but this is extended to at least 6 weeks in people with relapsing disease. Even mild cases are recommended to be treated to decrease the chance of inadvertently transmitting the infection by donating blood. In life-threatening cases, exchange transfusion is performed. In this procedure, the infected red blood cells are removed and replaced with uninfected ones.

Imizol is a drug used for treatment of babesiosis in dogs.

Extracts of the poisonous, bulbous plant "Boophone disticha" are used in the folk medicine of South Africa to treat equine babesiosis. "B. disticha" is a member of the daffodil family Amaryllidaceae and has also been used in preparations employed as arrow poisons, hallucinogens, and in embalming. The plant is rich in alkaloids, some of which display an action similar to that of scopolamine.

In addition to evaluation of any symptoms and signs, various blood tests can be done:

- Venereal Disease Research Laboratory test (VDRL)

- Fluorescent treponemal antibody absorption (FTA-ABS)

- Rapid plasma reagin (RPR)

- Treponema pallidum particle agglutination assay (TPPA)

Also, it is important to test the cerebrospinal fluid for signs of syphilis.

Additional tests to look for problems with the nervous system may include the following:

- Cerebral angiogram

- Head CT scan

- Lumbar puncture ("spinal tap") to acquire a sample for cerebrospinal fluid analysis

- MRI scan of the brain, brainstem, or spinal cord

The disease can be prevented in horses with the use of vaccinations. These vaccinations are usually given together with vaccinations for other diseases, most commonly WEE, VEE, and tetanus. Most vaccinations for EEE consist of the killed virus. For humans there is no vaccine for EEE so prevention involves reducing the risk of exposure. Using repellent, wearing protective clothing, and reducing the amount of standing water is the best means for prevention

This bacterium is present in soil and is transmitted to horses through open wounds, abrasions or mucous membranes.