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.

Specific helminths can be identified through microscopic examination of their eggs (ova) found in faecal samples. The number of eggs is measured in units of eggs per gram. However, it does not quantify mixed infections, and in practice, is inaccurate for quantifying the eggs of schistosomes and soil-transmitted helmiths. Sophisticated tests such as serological assays, antigen tests, and molecular diagnosis are also available; however, they are time-consuming, expensive and not always reliable.

Sparganosis is typically diagnosed following surgical removal of the worms, although the infection may also be diagnosed by identification of eosinophilia or identification of the parasite in a tissue specimen. If such biopsy and excision procedures are not feasible, the antisparganum ELISA test may be used. In theory, a pre-operative diagnosis could be made by identification of exposure history and a painful, migratory, subcutaneous nodule. Sparganosis usually presents as a single nodule, while other cestode infections such as cysticercosis typically present as multiple nodules. Preoperative diagnosis, however, is rare.

CT and MRI scans are especially useful for diagnosis of cerebral sparganosis, as they reveal lesions in the brain. Through a retrospective analysis of 25 cases of cerebral sparganosis from 2000 to 2006, Song et al. found a number of characteristic signs that could be used in the future to diagnose cerebral sparganosis without performing an excision or tissue biopsy. The most characteristic finding was the "tunnel sign" on MRI images, showing the migrating track of the worm, while the most common finding was multiple conglomerated ring-shaped enhancements, seen as bead-shaped, usually with 3 to 6 rings. These findings led Song et al. to suggest that clinical history, ELISA, and either MRI or CT scans could be sufficient to make a sparganosis diagnosis. These lesions, however, are sometimes mistaken for tuberculosis lesions. In one case cerebral sparganosis was not diagnosed for four years, during which scans showed a cluster of rings moving from the right to the left side of the brain; ultimately the worm was found on biopsy.

German entomologist Fritz Zumpt describes myiasis as "the infestation of live human and vertebrate animals with dipterous larvae, which at least for a period, feed on the host's dead or living tissue, liquid body substances, or ingested food". For modern purposes however, this is too vague. For example, feeding on dead or necrotic tissue is not generally a problem except when larvae such as those of flies in the family Piophilidae attack stored food such as cheese or preserved meats; such activity suggests saprophagy rather than parasitism; it even may be medically beneficial in maggot debridement therapy (MDT).

Currently myiasis commonly is classified according to aspects relevant to the case in question:

- The classical description of myiasis is according to the part of the host that is infected. This is the classification used by ICD-10. For example:

- dermal

- sub-dermal

- cutaneous (B87.0)

- creeping, where larvae burrow through or under the skin

- furuncular, where a larva remains in one spot, causing a boil-like lesion

- nasopharyngeal, in the nose, sinuses or pharynx (B87.3)

- ophthalmic or ocular, in or about the eye (B87.2)

- auricular, in or about the ear

- gastric, rectal, or intestinal/enteric for the appropriate part of the digestive system (B87.8)

- urogenital (B87.8)

- Another aspect is the relationship between the host and the parasite and provides insight into the biology of the fly species causing the myiasis and its likely effect. Thus the myiasis is described as either:

- obligatory, where the parasite cannot complete its life cycle without its parasitic phase, which may be specific, semispecific, or opportunistic

- facultative, incidental, or accidental, where it is not essential to the life cycle of the parasite; perhaps a normally free-living larva accidentally gained entrance to the host

Accidental myiasis commonly is enteric, resulting from swallowing eggs or larvae with one's food. The effect is called "pseudomyiasis". One traditional cause of pseudomyiasis was the eating of maggots of cheese flies in cheeses such as Stilton. Depending on the species present in the gut, pseudomyiasis may cause significant medical symptoms, but it is likely that most cases pass unnoticed.

Examination of blood samples will allow identification of microfilariae of "M. perstans", and "M. ozzardi" based. This diagnosis can be made on the basis of the morphology of the nuclei distribution in the tails of the microfilariae. The blood sample can be a thick smear, stained with Giemsa or hematoxylin and eosin. For increased sensitivity, concentration techniques can be used. These include centrifugation of the blood sample lyzed in 2% formalin (Knott's technique), or filtration through a Nucleopore membrane.

Examination of skin snips will identify microfilariae of "Onchocerca volvulus" and "M. streptocerca". Skin snips can be obtained using a corneal-scleral punch, or more simply a scalpel and needle. It is important that the sample be allowed to incubate for 30 minutes to 2 hours in saline or culture medium and then examined. This allows for the microfilariae that would have been in the tissue to migrate to the liquid phase of the specimen. Additionally, to differentiate the skin-dwelling filariae "M. streptocerca" and "Onchocerca volvulus", a nested polymerase chain reaction (PCR) assay was developed using small amounts of parasite material present in skin biopsies.

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 first control method is preventive and aims to eradicate the adult flies before they can cause any damage and is called vector control. The second control method is the treatment once the infestation is present, and concerns the infected animals (including humans).

The principal control method of adult populations of myiasis inducing flies involves insecticide applications in the environment where the target livestock is kept. Organophosphorus or organochlorine compounds may be used, usually in a spraying formulation. One alternative prevention method is the sterile insect technique (SIT) where a significant number of artificially reared sterilized (usually through irradiation) male flies are introduced. The male flies compete with wild breed males for females in order to copulate and thus cause females to lay batches of unfertilized eggs which cannot develop into the larval stage.

One prevention method involves removing the environment most favourable to the flies, such as by removal of the tail. Another example is the crutching of sheep, which involves the removal of wool from around the tail and between the rear legs, which is a favourable environment for the larvae. Another, more permanent, practice which is used in some countries is mulesing, where skin is removed from young animals to tighten remaining skin – leaving it less prone to fly attack.

To prevent myiasis in humans, there is a need for general improvement of sanitation, personal hygiene, and extermination of the flies by insecticides. Clothes should be washed thoroughly, preferably in hot water, dried away from flies, and ironed thoroughly. The heat of the iron kills the eggs of myiasis-causing flies.

Because they live so close to the outside of the body, "Thelazia" is one of the few nematode infections which can be treated topically.

Topical treatment of livestock, dogs and cats with organophosphates (such as ecothiopate iodide or isofluorophate) and systemic treatment with anthelmintics (such as ivermectin, levamisole, and doramectin) are recommended by the Merck Veterinary Manual. Other sources have reported positive results treating dogs with moxidectin, imidacloprid, or milbemycin oxime.

For the treatment of human cases, removal of the worm is suggested. Topical treatment with cocaine or thiabendazole have also been reported to kill the worms in human cases.

Because most, if not all, species of "Thelazia" are spread by flies, sanitary practices which reduce the presence of flies will also reduce the spread of thelaziasis.

The standard method for diagnosing active infection is by finding the microfilariae via microscopic examination. This may be difficult, as in most parts of the world, microfilariae only circulate in the blood at night. For this reason, the blood has to be collected nocturnally. The blood sample is typically in the form of a thick smear and stained with Giemsa stain. Testing the blood serum for antibodies against the disease may also be used.

Because sparganosis is a rare infection, public health strategies have not made its prevention a priority. Public health strategies focusing on providing basic access to clean water may help to reduce future sparganosis infections. In their retrospective study of 25 cases of cerebral sparganosis, Song et al. found that 12 patients (48%) had eaten raw or uncooked frog or snake that was infected with sparganum, 5 patients (20%) had applied an animal's flesh as a poultice to an open wound, 4 patients had drunk contaminated water, and the cause of infection was not known for 4 patients. As a result of these findings, Song et al. conclude that health education about sparganosis and the importance of food sanitation should be implemented in all rural endemic areas. It has been recommended that water consumed in endemic areas should be boiled or treated to prevent ingestion of Cyclops or Spirometra larvae. Especially in areas where ponds or ditches provide potential habitats for infected copepods, public health strategies should include education campaigns about how to identify drinking water that could potentially be infected. Strategies should warn people against ingesting the raw flesh of the intermediate hosts, such as snakes and frogs, and against using them as poultices.

In regions where helminthiasis is common, mass deworming treatments may be performed, particularly among school-age children, who are a high-risk group. Most of these initiatives are undertaken by the World Health Organization (WHO) with positive outcomes in many regions. Deworming programs can improve school attendance by 25 percent. Although deworming improves the health of an individual, outcomes from mass deworming campaigns, such as reduced deaths or increases in cognitive ability, nutritional benefits, physical growth, and performance, are uncertain or not apparent.

Parasitic infections can usually be treated with antiparasitic drugs.

Albendazole and mebendazole have been the treatments administered to entire populations to control hookworm infection. However, it is a costly option and both children and adults become reinfected within a few months after deparasitation occurs raising concerns because the treatment has to repeatedly be administered and drug resistance may occur.

Another medication administered to kill worm infections has been pyrantel pamoate. For some parasitic diseases, there is no treatment and, in the case of serious symptoms, medication intended to kill the parasite is administered, whereas, in other cases, symptom relief options are used. Recent papers have also proposed the use of viruses to treat infections caused by protozoa.

Symptoms of early scabies infestation mirror other skin diseases, including dermatitis, syphilis, erythema multiforme, various urticaria-related syndromes, allergic reactions, ringworm-related diseases, and other ectoparasites such as lice and fleas.

Under most situations, infection is hard to recognize because the symptoms are mild or even absent. In humans and wild animals, infection is not easily identified. Especially the adult flukes, even if in large number, generally do not cause complications. There is not yet a standard diagnostic test. Therefore, manual diagnosis is done at many levels. Diagnosis basically relies on a combination of postmortem analyses, clinical signs displayed by the animals, and response to drenching. In heavy infection, symptoms are easily observed in sheep and cattle as they become severely anorexic or inefficiently digest food, and become unthrifty. Copious fetid diarrhea is an obvious indication, as the soiling of hind legs and tails with fluid feces are readily noticeable. Even though it not always the case, immature flukes can be identified from the fluid excrement. On rare occasions, eggs can be identified from stools of suspected animals. In developing countries diagnosis and prognosis is often hindered by multiple infections with other trematodes, such as "Fasciola hepatica" and schistosomes, because these flukes are given primary importance due to their pervasive nature.

There are no diagnostic tests for tungiasis. This is most likely because the parasite is ectoparasitic with visible symptoms. Identification of the parasite through removal, and a patient’s traveling history, should suffice for diagnosis, though the latter is clearly more useful than the former. Localization of the lesion may be a useful diagnostic method for the clinician. A biopsy may be done, though again, it is not required for diagnosis.

Diagnosis depends on finding the eggs or the adult pinworms. Individual eggs are invisible to the naked eye, but they can be seen using a low-power microscope. On the other hand, the light-yellowish thread-like adult pinworms are clearly visually detectable, usually during the night when they move near the anus, or on toilet paper. Transparent adhesive tape (e.g. Scotch Tape) applied on the anal area will pick up deposited eggs, and diagnosis can be made by examining the tape with a microscope. This test is most successful if done every morning for several days, because the females do not lay eggs every day, and the number of eggs vary.

Pinworms do not lay eggs in the feces, but sometimes eggs are deposited in the intestine. As such, routine examination of fecal material gives a positive diagnosis in only 5 to 15% of infected subjects, and is therefore of little practical diagnostic use. In a heavy infection, female pinworms may adhere to stools that pass out through the anus, and they may thus be detected on the surface on the stool. Adult pinworms are occasionally seen during colonoscopy. On a microscopic level, pinworms have an identifying feature of alae (i.e., protruding ridges) running the length of the worm.

Pinworm infection cannot be totally prevented under most circumstances. This is due to the prevalence of the parasite and the ease of transmission through soiled night clothes, airborne eggs, contaminated furniture, toys and other objects. Infection may occur in the highest strata of society, where hygiene and nutritional status are typically high. The stigma associated with pinworm infection is hence considered a possible over-emphasis. Counselling is sometimes needed for upset parents that have discovered their children are infected, as they may not realize how prevalent the infection is.

Preventative action revolves around personal hygiene and the cleanliness of the living quarters. The "rate" of reinfection can be reduced through hygienic measures, and this is recommended especially in recurring cases.

The main measures are keeping fingernails short, and washing and scrubbing hands and fingers carefully, especially after defecation and before meals. Under ideal conditions, bed covers, sleeping garments, and hand towels should be changed daily. Simple laundering of clothes and linen disinfects them. Children should wear gloves while asleep, and the bedroom floor should be kept clean. Food should be covered to limit contamination with dust-borne parasite eggs. Household detergents have little effect on the viability of pinworm eggs, and cleaning the bathroom with a damp cloth moistened with an antibacterial agent or bleach will merely spread the still-viable eggs. Similarly, shaking clothes and bed linen will detach and spread the eggs.

Scabies may be diagnosed clinically in geographical areas where it is common when diffuse itching presents along with either lesions in two typical spots or itchiness is present in another household member. The classical sign of scabies is the burrow made by a mite within the skin. To detect the burrow, the suspected area is rubbed with ink from a fountain pen or a topical tetracycline solution, which glows under a special light. The skin is then wiped with an alcohol pad. If the person is infected with scabies, the characteristic zigzag or S pattern of the burrow will appear across the skin; however, interpreting this test may be difficult, as the burrows are scarce and may be obscured by scratch marks. A definitive diagnosis is made by finding either the scabies mites or their eggs and fecal pellets. Searches for these signs involve either scraping a suspected area, mounting the sample in potassium hydroxide and examining it under a microscope, or using dermoscopy to examine the skin directly.

By one author's count, 257 human cases of "Thelazia callipaeda" had been reported worldwide by the year 2000, though thelaziasis is still considered to be a rare disease.

Various livestock and wildlife surveys suggest that thelaziasis is quite common among animals.

- A slaughterhouse survey in Canada found that about one-third (32%) of cattle over an 8-month period were infested with eyeworms.

- A survey of horses in Kentucky revealed a 42% rate of infestation with "Thelazia lacrymalis".

- In Wyoming and Utah, a survey of hunter-harvested mule deer found 15% to be infested by "Thelazia californiensis".

- A survey of various sites in Italy found 23-60% of dogs, 5% of foxes and 4 out of 4 cats to be infested with "Thelazia callipaeda".

The condition is diagnosed by finding live lice in the hair. Finding empty eggs is not enough. This is made easier by using a magnifying glass or running a comb through the child's hair. In questionable cases, a child can be referred to a health professional. However, the condition is overdiagnosed, with extinct infestations being mistaken for active ones. As a result, lice-killing treatments are more often used on noninfested than infested children. The use of a louse comb is the most effective way to detect living lice. With both methods, special attention should be paid to the area near the ears and the nape of the neck. The use of a magnifying glass to examine the material collected between the teeth of the comb could prevent misdiagnosis.

The presence of nits alone, however, is not an accurate indicator of an active head louse infestation. Generally, white nits are empty egg casings, while brown nits may still contain viable louse larva. One way of determining the nit is to squeeze it between two fingernails; it gives a characteristic snapping pop sound as the egg bursts. Children with nits on their hair have a 35–40% chance of also being infested with living lice and eggs. If lice are detected, the entire family needs to be checked (especially children up to the age of 13 years) with a louse comb, and only those who are infested with living lice should be treated. As long as no living lice are detected, the child should be considered negative for head louse infestation. Accordingly, a child should be treated with a pediculicide only when living lice are detected on their hair (not because he/she has louse eggs/nits on the hair and not because the scalp is itchy).

Prevention can be partially achieved through limiting contact with vectors through the use of DEET and other repellents, but due to the predominantly relatively mild symptoms and the infection being generally asymptomatic, little has formally been done to control the disease.

One strategy for the prevention of infection transmission between cats and people is to better educate people on the behaviour that puts them at risk for becoming infected.

Those at the highest risk of contracting a disease from a cat are those with behaviors that include: being licked, sharing food, sharing kithchen utensils, kissing, and sleeping with a cat. The very young, the elderly and those who are immunocompromised increase their risk of becoming infected when sleeping with their cats (and dogs). The CDC recommends that cat owners not allow a cat to lick your face because it can result in disease transmission. If someone is licked on their face, mucous membranes or an open wound, the risk for infection is reduced if the area is immediately washed with soap and water. Maintaining the health of the animal by regular inspection for fleas and ticks, scheduling deworming medications along with veterinary exams will also reduce the risk of acquiring a feline zoonosis.

Recommendations for the prevention of ringworm transmission to people include:

- regularly vacuuming areas of the home that pets commonly visit helps to remove fur or flakes of skin

- washing the hands with soap and running water after playing with or petting your pet.

- wearing gloves and long sleeves when handling cats infected with.

- disinfect areas the pet has spent time in, including surfaces and bedding.

- the spores of this fungus can be killed with common disinfectants like chlorine bleach diluted 1:10 (1/4 cup in 1 gallon of water), benzalkonium chloride, or strong detergents.

- not handling cats with ringworm by those whose immune system is weak in any way (if you have HIV/AIDS, are undergoing cancer treatment, or are taking medications that suppress the immune system, for example).

- taking the cat to the veterinarian if ringworm infection is suspected.

The World Health Organization recommends mass deworming—treating entire groups of people who are at risk with a single annual dose of two medicines, namely albendazole in combination with either ivermectin or diethylcarbamazine citrate. With consistent treatment, since the disease needs a human host, the reduction of microfilariae means the disease will not be transmitted, the adult worms will die out, and the cycle will be broken. In sub-Saharan Africa, albendazole (donated by GlaxoSmithKline) is being used with ivermectin (donated by Merck & Co.) to treat the disease, whereas elsewhere in the world, albendazole is used with diethylcarbamazine. Transmission of the infection can be broken when a single dose of these combined oral medicines is consistently maintained annually for a duration of four to six years. Using a combination of treatments better reduces the number of microfilariae in blood. Avoiding mosquito bites, such as by using insecticide-treated mosquito bed nets, also reduces the transmission of lymphatic filariasis.

The Carter Center's International Task Force for Disease Eradication declared lymphatic filariasis one of six potentially eradicable diseases. According to medical experts, the worldwide effort to eliminate lymphatic filariasis is on track to potentially succeed by 2020.

For similar-looking but causally unrelated podoconiosis, international awareness of the disease will have to increase before elimination is possible. In 2011, podoconiosis was added to the World Health Organization's Neglected Tropical Diseases list, which was an important milestone in raising global awareness of the condition.

The efforts of the Global Programme to Eliminate LF are estimated to have prevented 6.6 million new filariasis cases from developing in children between 2000 and 2007, and to have stopped the progression of the disease in another 9.5 million people who had already contracted it. Dr. Mwele Malecela, who chairs the programme, said: "We are on track to accomplish our goal of elimination by 2020." In 2010, the WHO published a detailed progress report on the elimination campaign in which they assert that of the 81 countries with endemic LF, 53 have implemented mass drug administration, and 37 have completed five or more rounds in some areas, though urban areas remain problematic.

Cure rates are extremely good with modern treatments, but successful cure results may be of no symptomatic benefit to patients.

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.