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.

For medical purposes, the exact number of helminth eggs is less important and therefore most diagnoses are made simply by identifying the appearance of the worm or eggs in feces. Due to the large quantity of eggs laid, physicians can diagnose using only one or two fecal smears. The Kato technique (also called the Kato-Katz technique) is a laboratory method for preparing human stool samples prior to searching for parasite eggs. Eggs per gram is a laboratory test that determines the number of eggs per gram of feces in patients suspected of having a parasitological infection, such as schistosomiasis.

For the purpose of setting treatment standards and reuse legislation, it is important to be able to determine the amount of helminth eggs in an environmental sample with some accuracy. The detection of viable helminth eggs in samples of wastewater, sludge or fresh feces (as a diagnostic tool for the infection helminthiasis) is not straight forward. In fact, many laboratories in developing countries lack the right equipment or skilled staff required to do so. An important step in the analytical methods is usually the concentration of the eggs in the sample, especially in the case of wastewater samples. A concentration step may not be required in samples of dried feces, e.g. samples collected from urine-diverting dry toilets.

A stool ova and parasites exam reveals the presence of typical whipworm eggs. Typically, the Kato-Katz thick-smear technique is used for identification of the "Trichuris trichiura" eggs in the stool sample.

Although colonoscopy is not typically used for diagnosis, as the adult worms can be overlooked, especially with imperfect colon, there have been reported cases in which colonoscopy has revealed adult worms. Colonoscopy can directly diagnose trichuriasis by identification of the threadlike form of worms with an attenuated, whip-like end. Colonoscopy has been shown to be a useful diagnostic tool, especially in patients infected with only a few male worms and with no eggs presenting in the stool sample.

Trichuriasis can be diagnosed when "T. trichiura" eggs are detected in stool examination. Eggs will appear barrel-shaped and unembryonated, having bipolar plugs and a smooth shell. Rectal prolapse can be diagnosed easily using defecating proctogram and is one of many methods for imaging the parasitic infection. Sigmoidoscopys show characteristic white bodies of adult worms hanging from inflamed mucosa ("coconut cake rectum").

For basic diagnosis, specific helminths can be generally identified from the faeces, and their eggs microscopically examined and enumerated using fecal egg count method. However, there are certain limitations such as the inability to identify mixed infections, and on clinical practice, the technique is inaccurate and unreliable.

A novel effective method for egg analysis is the Kato-Katz technique. It is a highly accurate and rapid method for "A. lumbricoides" and "T. trichiura"; however not so much for hookworm, which could be due to fast degeneration of the rather delicate hookworm eggs.

Antibody detection can be useful to indicate schistosome infection in people who have traveled to areas where schistosomiasis is common and in whom eggs cannot be demonstrated in fecal or urine specimens. Test sensitivity and specificity vary widely among the many tests reported for the serologic diagnosis of schistosomiasis and are dependent on both the type of antigen preparations used (crude, purified, adult worm, egg, cercarial) and the test procedure.

At CDC, a combination of tests with purified adult worm antigens is used for antibody detection. All serum specimens are tested by FAST-ELISA using "S. mansoni" adult microsomal antigen (MAMA). A positive reaction (greater than 9 units/µl serum) indicates infection with "Schistosoma" species. Sensitivity for "S. mansoni" infection is 99 percent, 95 percent for "S. haematobium" infection, and less than 50 percent for "S. japonicum" infection. Specificity of this assay for detecting schistosome infection is 99 percent. Because test sensitivity with the FAST-ELISA is reduced for species other than "S. mansoni", immunoblots of the species appropriate to the patient's travel history are also tested to ensure detection of "S. haematobium" and "S. japonicum" infections. Immunoblots with adult worm microsomal antigens are species-specific and so a positive reaction indicates the infecting species. The presence of antibody is indicative only of schistosome infection at some time and cannot be correlated with clinical status, worm burden, egg production, or prognosis. Where a person has traveled can help determine what "Schistosoma" species to test for by immunoblot.

In 2005, a field evaluation of a novel handheld microscope was undertaken in Uganda for the diagnosis of intestinal schistosomiasis by a team led by Russell Stothard from the Natural History Museum of London, working with the Schistosomiasis Control Initiative, London.

Diagnosis of infection is confirmed by the identification of eggs in stools. Eggs of "S. mansoni" are approximately 140 by 60 µm in size, and have a lateral spine. The diagnosis is improved by the use of the Kato-Katz technique (a semi-quantitative stool examination technique). Other methods that can be used are enzyme-linked immunosorbent assay (ELISA), circumoval precipitation test, and alkaline phosphatase immunoassay.

Microscopic identification of eggs in stool or urine is the most practical method for diagnosis. Stool examination should be performed when infection with "S. mansoni" or "S. japonicum" is suspected, and urine examination should be performed if "S. haematobium" is suspected. Eggs can be present in the stool in infections with all "Schistosoma" species. The examination can be performed on a simple smear (1 to 2 mg of fecal material). Since eggs may be passed intermittently or in small amounts, their detection will be enhanced by repeated examinations and/or concentration procedures. In addition, for field surveys and investigational purposes, the egg output can be quantified by using the Kato-Katz technique (20 to 50 mg of fecal material) or the Ritchie technique. Eggs can be found in the urine in infections with "S. haematobium" (recommended time for collection: between noon and 3 PM) and with "S. japonicum". Quantification is possible by using filtration through a nucleopore filter membrane of a standard volume of urine followed by egg counts on the membrane. Tissue biopsy (rectal biopsy for all species and biopsy of the bladder for "S. haematobium") may demonstrate eggs when stool or urine examinations are negative.

Limited access to essential medicine poses a challenge to the eradication of trichuriasis worldwide. Also, it is a public health concern that rates of post-treatment re-infection need to be determined and addressed to diminish the incidence of untreated re-infection. Lastly, with mass drug administration strategies and improved diagnosis and prompt treatment, detection of an emergence of antihelminthic drug resistance should be examined.

Mass Drug Administration (preventative chemotherapy) has had a positive effect on the disease burden of trichuriasis in East and West Africa, especially among children, who are at highest risk for infection.

Diagnosis depends on finding characteristic worm eggs on microscopic examination of the stools, although this is not possible in early infection. Early signs of infection in most dogs include limbular limping and anal itching. The eggs are oval or elliptical, measuring 60 µm by 40 µm, colorless, not bile stained and with a thin transparent hyaline shell membrane. When released by the worm in the intestine, the egg contains an unsegmented ovum. During its passage down the intestine, the ovum develops and thus the eggs passed in feces have a segmented ovum, usually with 4 to 8 blastomeres.

As the eggs of both "Ancylostoma" and "Necator" (and most other hookworm species) are indistinguishable, to identify the genus, they must be cultured in the lab to allow larvae to hatch out. If the fecal sample is left for a day or more under tropical conditions, the larvae will have hatched out, so eggs might no longer be evident. In such a case, it is essential to distinguish hookworms from "Strongyloides" larvae, as infection with the latter has more serious implications and requires different management. The larvae of the two hookworm species can also be distinguished microscopically, although this would not be done routinely, but usually for research purposes. Adult worms are rarely seen (except via endoscopy, surgery or autopsy), but if found, would allow definitive identification of the species. Classification can be performed based on the length of the buccal cavity, the space between the oral opening and the esophagus: hookworm rhabditoform larvae have long buccal cavities whereas "Strongyloides" rhabditoform larvae have short buccal cavities.

Recent research has focused on the development of DNA-based tools for diagnosis of infection, specific identification of hookworm, and analysis of genetic variability within hookworm populations. Because hookworm eggs are often indistinguishable from other parasitic eggs, PCR assays could serve as a molecular approach for accurate diagnosis of hookworm in the feces.

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.

Prevention and control measures to prevent soil-transmitted helminthiasis are the following: availability of clean water for personal and domestic uses, improved access to sanitation which includes the use of properly functioning and clean toilets by all community members, education on personal hygiene such as hand washing and hygienic and safe food preparation; eliminating the use of untreated human faeces as fertilizer.

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.

Evaluation of numerous public health interventions has generally shown that improvement in each individual component ordinarily attributed to poverty (for example, sanitation, health education and underlying nutrition status) often have minimal impact on transmission. For example, one study found that the introduction of latrines into a resource-limited community only reduced the prevalence of hookworm infection by four percent. However, another study in Salvador, Brazil found that improved drainage and sewerage had a significant impact (p<0.0001) on the prevalence of hookworm infection but no impact at all on the intensity of hookworm infection. This seems to suggest that environmental control alone has a limited but incomplete effect on the transmission of hookworms. It is imperative, therefore, that more research is performed to understand the efficacy and sustainability of integrated programs that combine numerous preventive methods including education, sanitation, and treatment.

Diagnosis rests on the microscopic identification of larvae (rhabditiform and occasionally filariform) in the stool or duodenal fluid. Examination of many samples may be necessary, and not always sufficient, because direct stool examination is relatively insensitive, with a single sample only able to detect larvae in about 25% of cases. It can take 4 weeks from initial infection to the passage of larvae in the stool.

The stool can be examined in wet mounts:

- directly

- after concentration (formalin-ethyl acetate)

- after recovery of the larvae by the Baermann funnel technique

- after culture by the Harada-Mori filter paper technique

- after culture in agar plates

Culture techniques are the most sensitive, but are not routinely available in the West. In the UK, culture is available at either of the Schools of Tropical Medicine in Liverpool or London. Direct examination must be done on stool that is freshly collected and not allowed to cool down, because hookworm eggs hatch on cooling and the larvae are very difficult to distinguish from Strongyloides.

Finding Strongyloides in the stool is negative in up to 70% of tests. It is important to undergo frequent stool sampling as well as duodenal biopsy if a bad infection is suspected. The duodenal fluid can be examined using techniques such as the Enterotest string or duodenal aspiration. Larvae may be detected in sputum from patients with disseminated strongyloidiasis.

Given the poor ability of stool examination to diagnose strongyloides, detecting antibodies by ELISA can be useful. Serology can cross-react with other parasites, remain positive for years after successful treatment or be falsely negative in immunocompromised patients. Infected patients will also often have an elevated eosinophil count, with an average of absolute eosinophil count of 1000 in one series. The combination of clinical suspicion, a positive antibody and a peripheral eosinophilia can be strongly suggestive of infection.

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.

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.

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.

Anecdotal data gathered from helminth self-treaters and their physicians and presented in socio-medical studies suggest that a much larger number of diseases may be amenable to helminthic therapy than are currently being investigated by formal clinical trials.

The drug of choice for the treatment of uncomplicated strongyloidiasis is ivermectin. Ivermectin does not kill the "Strongyloides" larvae, only the adult worms, therefore repeat dosing may be necessary to properly eradicate the infection. There is an auto-infective cycle of roughly two weeks in which Ivermectin should be re-administered however additional dosing may still be necessary as it will not kill "Strongyloides" in the blood or larvae deep within the bowels or diverticula. Other drugs that are effective are albendazole and thiabendazole (25 mg/kg twice daily for 5 days—400 mg maximum (generally)). All patients who are at risk of disseminated strongyloidiasis should be treated. The optimal duration of treatment for patients with disseminated infections is not clear.

Treatment of strongyloidiasis can be difficult and "Strongyloides" has been known to live in individuals for decades; even after treatment. Continued treatment is thus necessary even if symptoms resolve.

Because of the high cost of Stromectol, the veterinary formula Ivomec can be used. Government programs are needed to help citizens finance lifelong medication.

Clothes and sheets must be washed with enzyme washing powder and dried on hot daily.

Biotechnology companies in the developing world have targeted neglected tropical diseases due to need to improve global health.

Mass drug administration is considered a possible method for eradication, especially for lymphatic filariasis, onchocerciasis, and trachoma, although drug resistance is a potential problem. According to Fenwick, Pfizer donated 70 million doses of drugs in 2011 to eliminate trachoma through the International Trachoma Initiative. Merck has helped The African Programme for the Control of Onchocerciasis (APOC) and Oncho Elimination Programme for the Americas to greatly diminished the effect of Onchocerciasis by donating ivermectin. Merck KGaA pledged to give 200 million tablets of praziquantel over 10 years, the only cure for schistosomiasis. GlaxoSmithKline has donated two billion tablets of medicine for lymphatic filariasis and pledged 400 million deworming tablets per year for five years in 2010. Johnson & Johnson has pledged 200 million deworming tablets per year. Novartis has pledged leprosy treatment, EISAI pledged two billion tablets to help treat lymphatic filariasis.

Evidence in support of the idea that helminthic infections reduce the severity of autoimmune diseases is primarily derived from animal models. Studies conducted on mice and rat models of colitis, muscular sclerosis, type 1 diabetes, and asthma have shown helminth-infected subjects to display protection from the disease. While helminths are often considered a homogenous group, considerable differences exist between species and the utilization of species in clinical research varies between human and animal trials. As such, caution must be exercised when interpreting the results from animal models.

Helminthic therapy is currently being studied as a treatment for several (non-viral) autoimmune diseases in humans including celiac disease, Crohn's disease, multiple sclerosis, ulcerative colitis, and atherosclerosis. It is currently unknown which clinical dose or species of helminth is the most effective method of treatment. Hookworms have been linked to reduced risk of developing asthma, while "Ascaris lumbricoides" (roundworm infection) was associated with an "increased" risk of asthma. Similarly, "Hymenolepis nana", "Trichoris trichiura", "Ascaris lumbricoides", "Strongyloides stercolaris", "Enterobius vermicularis", and "Trichuris suis" ova have all been found to lower the number of symptom exacerbations, reduce the number of symptom relapses, and decrease the number of new or enlarging brain lesions in patients with multiple sclerosis at doses ranging from 1,180 to 9,340 eggs per gram. However, "Ascaris lumbricoides", "Strongyloides stercolaris" and "Enterobius vermicularis" are not considered suitable for therapeutic use in humans because they do not meet the criteria for a therapeutic helminth.

"Trichuris suis" ova has been used in most cases to treat autoimmune disorders because it is thought to be non-pathogenic in humans and therefore has been rendered as safe.

The use of "Trichuris suis" ova has been granted by the USA Food and Drug Administration as an investigational medicinal product (IMP). While in the UK, the hookworm "Necator americanus" has been granted an IMP license by the Medicines and Healthcare Regulatory Authority. This hookworm is likely to be relatively safe, although it can cause temporary gastrointestinal side effects, especially following the initial inoculation and with larger doses.

The general ideal characteristics for a therapeutic helminth are as follows:

- Little or no pathogenic potential

- Does not multiply in the host

- Cannot be directly spread to close contacts

- Produces a self-limited colonization in humans

- Produces an asymptomatic colonization in humans

- Does not alter behaviour in patients with depressed immunity

- Is not affected by most commonly used medications

- Can be eradicated with an anti-helminthic drug

- Can be isolated free of other potential pathogens

- Can be isolated or produced in large numbers

- Can be made stable for transport and storage

- Easy to administer

Inclusion of NTDs into initiatives for malaria, HIV/AIDS, and tuberculosis, as well as integration of NTD treatment programs, may have advantages given the strong link between these diseases and NTDs. Some neglected tropical diseases share common vectors (sandflies, black flies, and mosquitos). Both medicinal and vector control efforts may be combined.

A four-drug rapid-impact package has been proposed for widespread proliferation. Administration may be made more efficient by targeting multiple diseases at once, rather than separating treatment and adding work to community workers. This package is estimated to cost US$0.40 per patient. When compared to stand-alone treatment, the savings are estimated to be 26–47%. While more research must be done in order to understand how NTDs and other diseases interact in both the vector and the human stages, safety assessments have so far produced positive results.

Many neglected tropical diseases and other prevalent diseases share common vectors, creating another opportunity for treatment and control integration. One such example of this is malaria and lymphatic filariasis. Both diseases are transmitted by the same or related mosquito vectors. Vector control, through the distribution of insecticide treated nets, reduces the human contact with a wide variety of disease vectors. Integrated vector control may also alleviate pressure on mass drug administration, especially with respect to rapidly evolving drug resistance. Combining vector control and mass drug administration deemphasizes both, making each less susceptible to resistance evolution.