Some conventional parasitological techniques (CPT) such as wet blood film, and stained blood smears are used because so far, the best identifier is looking at the blood of the potentially infected host. Other tissues can be looked at, but the gold standard is identifying trypanosomes in the blood. Before the infection becomes severe, it is difficult to catch as many times these cryptic infections are undetectable by direct microscopy. Since CPT is not very sensitive, it cannot be used as a sole method of diagnosis.

The Haematocrit Centrifugation Technique (HCT) is a much better alternative. Using HCT trypanosomes can be detected in the blood even in field conditions. Buffy coat can be used to increase detection. Detection with this method is approx 85 trypanosomes per millilitre.

Rather than using live animals as test subjects, Canada used serological tests such as complement fixation tests to detect trypanosomes, and have been very successful. Other tests used look at detecting antibodies generated by the host species against T.evansi antigens. This is done using the enzyme-linked immunosorbent assays (ELISA) method. Now polymerase chain reaction (PCR) and DNA probes are being used to detect Surra in animals.

The main methods of controlling surra has been chemotherapy, and chemoprophylaxis in animals.

A definitive diagnosis of health effects due to bed bugs requires a search for and finding of the insect in the sleeping environment as symptoms are not sufficiently specific. Other possible conditions with which these conditions can be confused include scabies, allergic reactions, mosquito bites, spider bites, chicken pox and bacterial skin infections. Bed bugs classically form a line of bites colloquially referred to as "breakfast, lunch, and dinner" and rarely feed in the armpit or behind the knee which may help differentiate it from other biting insects. If the number in a house is large a pungent sweet odor may be described.

The diagnosis of Buruli ulcer is usually based on the characteristic appearance of the ulcer in an endemic area. If there is any doubt about the diagnosis, then PCR using the IS2404 target is helpful, but this is not specific for "M. ulcerans". The Ziehl-Neelsen stain is only 40–80% sensitive, and culture is 20–60% sensitive. Simultaneous use of multiple methods may be necessary to make the diagnosis.

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.

Various concentration methods are applied: membrane filter, Knott's concentration method, and sedimentation technique.

Polymerase chain reaction (PCR) and antigenic assays, which detect circulating filarial antigens, are also available for making the diagnosis. The latter are particularly useful in amicrofilaraemic cases. Spot tests for antigen are far more sensitive, and allow the test to be done anytime, rather in the late hours.

Lymph node aspirate and chylous fluid may also yield microfilariae. Medical imaging, such as CT or MRI, may reveal "filarial dance sign" in the chylous fluid; X-ray tests can show calcified adult worms in lymphatics. The DEC provocation test is performed to obtain satisfying numbers of parasites in daytime samples. Xenodiagnosis is now obsolete, and eosinophilia is a nonspecific primary sign.

The presence of "T. cruzi" is diagnostic of Chagas disease. It can be detected by microscopic examination of fresh anticoagulated blood, or its buffy coat, for motile parasites; or by preparation of thin and thick blood smears stained with Giemsa, for direct visualization of parasites. Microscopically, "T. cruzi" can be confused with "Trypanosoma rangeli", which is not known to be pathogenic in humans. Isolation of "T. cruzi" can occur by inoculation into mice, by culture in specialized media (for example, NNN, LIT); and by xenodiagnosis, where uninfected Reduviidae bugs are fed on the patient's blood, and their gut contents examined for parasites.

Various immunoassays for "T. cruzi" are available and can be used to distinguish among strains (zymodemes of "T.cruzi" with divergent pathogenicities). These tests include: detecting complement fixation, indirect hemagglutination, indirect fluorescence assays, radioimmunoassays, and ELISA. Alternatively, diagnosis and strain identification can be made using polymerase chain reaction (PCR).

Some of the strategies for controlling tropical diseases include:

- Draining wetlands to reduce populations of insects and other vectors, or introducing natural predators of the vectors.

- The application of insecticides and/or insect repellents) to strategic surfaces such as clothing, skin, buildings, insect habitats, and bed nets.

- The use of a mosquito net over a bed (also known as a "bed net") to reduce nighttime transmission, since certain species of tropical mosquitoes feed mainly at night.

- Use of water wells, and/or water filtration, water filters, or water treatment with water tablets to produce drinking water free of parasites.

- Sanitation to prevent transmission through human waste.

- In situations where vectors (such as mosquitoes) have become more numerous as a result of human activity, a careful investigation can provide clues: for example, open dumps can contain stagnant water that encourage disease vectors to breed. Eliminating these dumps can address the problem. An education campaign can yield significant benefits at low cost.

- Development and use of vaccines to promote disease immunity.

- Pharmacologic pre-exposure prophylaxis (to prevent disease before exposure to the environment and/or vector).

- Pharmacologic post-exposure prophylaxis (to prevent disease after exposure to the environment and/or vector).

- Pharmacologic treatment (to treat disease after infection or infestation).

- Assisting with economic development in endemic regions. For example, by providing microloans to enable investments in more efficient and productive agriculture. This in turn can help subsistence farming to become more profitable, and these profits can be used by local populations for disease prevention and treatment, with the added benefit of reducing the poverty rate.

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Diagnosis is most commonly done with the identification of bacteria in the lesions by a microscope observation. Ticks, biting flies, and contact with other infected animals also causes the spread of rainscald. A scab will be taken from the affected animal and stained so that the bacteria are visible under a microscope inspection. A positive diagnosis of rainscald can be confirmed if filamentous bacteria are observed with as well as chains of small, spherical bacteria. If a diagnosis cannot be confirmed with a microscope, blood agar cultures can be grown to confirm the presence of "D. congolensis". The resulting colonies have filaments and are yellow in colour.

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.

There is no specific vaccine for "Myocobacterium ulcerans". The Bacillus Calmette-Guérin vaccine may offer temporary protection.

The number of diagnosed cases of human louse infestations (or pediculosis) has increased worldwide since the mid-1960s, reaching hundreds of millions annually. There is no product or method which assures 100% destruction of the eggs and hatched lice after a single treatment. However, there are a number of treatment methods that can be employed with varying degrees of success. These methods include chemical treatments, natural products, combs, shaving, hot air, silicone-based lotions, and ethanol (ethyl alcohol).

The pharmacological treatment of pediculosis include the use of crotamiton applied twice at 24 hour interval and washed off day after that. Benzyl benzoate also can be used when combined with lindane, it is applied once and then washed off after 24 hours.

There is currently no vaccine against Chagas disease. Prevention is generally focused on decreasing the numbers of the insect that spreads it ("Triatoma") and decreasing their contact with humans. This is done by using sprays and paints containing insecticides (synthetic pyrethroids), and improving housing and sanitary conditions in rural areas. For urban dwellers, spending vacations and camping out in the wilderness or sleeping at hostels or mud houses in endemic areas can be dangerous; a mosquito net is recommended. Some measures of vector control include:

- A yeast trap can be used for monitoring infestations of certain species of triatomine bugs ("Triatoma sordida", "Triatoma brasiliensis", "Triatoma pseudomaculata", and "Panstrongylus megistus").

- Promising results were gained with the treatment of vector habitats with the fungus "Beauveria bassiana".

- Targeting the symbionts of Triatominae through paratransgenesis can be done.

A number of potential vaccines are currently being tested. Vaccination with "Trypanosoma rangeli" has produced positive results in animal models. More recently, the potential of DNA vaccines for immunotherapy of acute and chronic Chagas disease is being tested by several research groups.

Blood transfusion was formerly the second-most common mode of transmission for Chagas disease, but the development and implementation of blood bank screening tests has dramatically reduced this risk in the 21st century. Blood donations in all endemic Latin American countries undergo Chagas screening, and testing is expanding in countries, such as France, Spain and the United States, that have significant or growing populations of immigrants from endemic areas. In Spain, donors are evaluated with a questionnaire to identify individuals at risk of Chagas exposure for screening tests.

The US FDA has approved two Chagas tests, including one approved in April 2010, and has published guidelines that recommend testing of all donated blood and tissue products. While these tests are not required in US, an estimated 75–90% of the blood supply is currently tested for Chagas, including all units collected by the American Red Cross, which accounts for 40% of the U.S. blood supply. The Chagas Biovigilance Network reports current incidents of Chagas-positive blood products in the United States, as reported by labs using the screening test approved by the FDA in 2007.

Filariasis is usually diagnosed by identifying microfilariae on Giemsa stained, thin and thick blood film smears, using the "gold standard" known as the finger prick test. The finger prick test draws blood from the capillaries of the finger tip; larger veins can be used for blood extraction, but strict windows of the time of day must be observed. Blood must be drawn at appropriate times, which reflect the feeding activities of the vector insects. Examples are "W. bancrofti", whose vector is a mosquito; night is the preferred time for blood collection. "Loa loa's" vector is the deer fly; daytime collection is preferred. This method of diagnosis is only relevant to microfilariae that use the blood as transport from the lungs to the skin. Some filarial worms, such as "M. streptocerca" and "O. volvulus", produce microfilarae that do not use the blood; they reside in the skin only. For these worms, diagnosis relies upon skin snips and can be carried out at any time.

The diagnosis by symptoms is not reliable enough so it’s better to do a molecular diagnosis based in test samples. Some of these methods (like Dot-blot hybridisation) allow the scientists to detect the viroid even six months before noticing the first symptoms.

The first step is the purification to obtain the nucleic acids of the plant cells. The leaves of the plant located four or more below the spare leaf are cut. Afterwards, they are blended (homogenize) with sodium sulfite. Then the extract is filtered and clarified by centrifugation (10.000 g during 10 minutes). The next step is to add polyethylene glycol (PEG). Finally, after nearly two hours of incubation at 4 °C, and after another centrifugation (at low speed) the nucleic acids can be extracted by chloroform procedures, for example.

When approximately 1 g of coconut tissue has been purified, the electrophoresis method can be started, which will help to identify the viroid by its relative mobility. The CCCVd is analysed in one or two dimensional polyacrylamide gels with a silver stain.

The viroid can also be detected by a more sensitive method called dot blot molecular hybridization. In this method CCCVd is amplified by the PCR (polymerase chain reaction) and the clones of CCCVd are used as templates to synthesize a complementary DNA or RNA chain. These sequences are radioactively labelled so when they are put over the samples with the intention to analyse (on a supporting membrane) and exposed to x-ray film, then if CCCVd is present it will appear as a dark colour. This dark tonality only appears when nucleic acid hybridisation occurs.

Treatment requires keeping the person from being repeatedly bitten and possible symptomatic use of antihistamines and corticosteroids (either topically or systemically). There however is no evidence that medications improve outcomes and symptoms usually resolve without treatment in 1–2 weeks.

Avoiding repeated bites can be difficult, since it usually requires eradicating bed bugs from a home or workplace; eradication frequently requires a combination of pesticide and non pesticide approaches. Pesticides that have historically been found to be effective include pyrethroids, dichlorvos and malathion. Resistance to pesticides has increased significantly over time and there are concerns of negative health effects from their usage. Mechanical approaches such as vacuuming up the insects and heat treating or wrapping mattresses have been recommended.

Outbreaks of zoonoses have been traced to human interaction with and exposure to animals at fairs, petting zoos, and other settings. In 2005, the Centers for Disease Control and Prevention (CDC) issued an updated list of recommendations for preventing zoonosis transmission in public settings. The recommendations, developed in conjunction with the National Association of State Public Health Veterinarians, include educational responsibilities of venue operators, limiting public and animal contact, and animal care and management.

Cattle infested with bovine pediculosis are generally treated chemically, by drugs like ivermectin and cypermethrin.

Tropical diseases are diseases that are prevalent in or unique to tropical and subtropical regions. The diseases are less prevalent in temperate climates, due in part to the occurrence of a cold season, which controls the insect population by forcing hibernation. However, many were present in northern Europe and northern America in the 17th and 18th centuries before modern understanding of disease causation. The initial impetus for tropical medicine was to protect the health of colonialists, notably in India under the British Raj. Insects such as mosquitoes and flies are by far the most common disease carrier, or vector. These insects may carry a parasite, bacterium or virus that is infectious to humans and animals. Most often disease is transmitted by an insect "bite", which causes transmission of the infectious agent through subcutaneous blood exchange. Vaccines are not available for most of the diseases listed here, and many do not have cures.

Human exploration of tropical rainforests, deforestation, rising immigration and increased international air travel and other tourism to tropical regions has led to an increased incidence of such diseases.

Adequate footwear is important to prevent trauma. General good health and nutrition also reduce ulcer risk. Adequate and prompt cleansing and treatment of ankle and leg skin breaks is also important. Improving hygiene and nutrition may help to prevent tropical ulcers.

Pets can transmit a number of diseases. Dogs and cats are routinely vaccinated against rabies. Pets can also transmit ringworm and "Giardia", which are endemic in both animal and human populations. Toxoplasmosis is a common infection of cats; in humans it is a mild disease although it can be dangerous to pregnant women. Dirofilariasis is caused by "Dirofilaria immitis" through mosquitoes infected by mammals like dogs and cats. Cat-scratch disease is caused by "Bartonella henselae" and "Bartonella quintana" from fleas which are endemic in cats. Toxocariasis is infection of humans of any of species of roundworm, including species specific to the dog ("Toxocara canis)" or the cat ("Toxocara cati"). Cryptosporidiosis can be spread to humans from pet lizards, such as the leopard gecko.

Washing the infected area with an antiseptic solution is part of the treatment for mud fever. However, washing a horse's legs repeatedly can remove the natural oils in the skin and may allow the condition to become established. The legs should be dried thoroughly after washing with antibacterial shampoo using paper towels,

Many species of arthropods (insects, arachnids and others) regularly or occasionally bite or sting human beings. Insect saliva contains anticoagulants and enzymes that cause local irritation and allergic reactions. Insect venoms can be delivered by their stingers, which often are modified ovipositors, or by their mouthparts. Insect, spider and scorpion venom can cause serious injury or death. Dipterans account for the majority of insect bites, while hymenopterans account for the majority of stings. Among arachnids spider bites are the most common. Arthropods bite or sting humans for a number of reasons including feeding or defense. Arthropods are major vectors of human disease, with the pathogens typically transmitted by bites.

One of the most important factors in successfully treating scratches is moving the horse to a clean and dry environment.

- Use paddock and pasture rotation and fences to keep horses from standing in wet and muddy ground for long periods of time.

- Keep the horse stall in the barn clean and dry.

- Avoid using leg wraps, tack items or devices that could increase moisture retention.

Although commercial tests are not readily available, diagnosis can be confirmed by serology-based assays or quantitative PCR by laboratories that have developed assays to perform such identification.