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 highest clearance rates are obtained by combining mebendazole or albendazole with ivermectin. Ivermectin's safety in children under and pregnant women has not yet been established.

People with diarrhea may be treated with loperamide to increase the amount of drug contact with the parasites.

Mebendazole is 90% effective in the first dose, and albendazole may also be offered as an anti-parasitic agent. Adding iron to the bloodstream helps solve the iron deficiency and rectal prolapse. Difetarsone is also an effective treatment.

Amphistomiasis is considered a neglected tropical disease, with no prescription drug for treatment and control. Therefore, management of infestation is based mainly on control of the snail population, which transmit the infective larvae of the flukes. However, there are now drugs shown to be effective including resorantel, oxyclozanide, clorsulon, ivermectin, niclosamide, bithional and levamisole. An in vitro demonstration shows that plumbagin exhibits high efficacy on adult flukes. Since the juvenile flukes are the causative individuals of the disease, effective treatment means control of the immature fluke population. Prophylaxis is therefore based on disruption of the environment (such as proper drainage) where the carrier snails inhabit, or more drastic action of using molluscicides to eradicate the entire population. For treatment of the infection, drugs effective against the immature flukes are recommended for drenching. For this reason oxyclozanide is advocated as the drug of choice. It effectively kills the flukes within a few hours and it effective against the flukes resistant to other drugs. The commercially prescribed dosage is 5 mg/kg body weight or 18.7 mg/kg body weight in two divided dose within 72 hours. Niclosamide is also extensively used in mass drenching of sheep. Successfully treated sheep regain appetite within a week, diarrhoea stops in about three days, and physiological indicators (such as plasma protein and albumin levels) return to normal in a month.

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.

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.

Moderate hookworm infections have been demonstrated to have beneficial effects on hosts suffering from diseases linked to overactive immune systems. This is possibly explained by the hygiene hypothesis. Research at the University of Nottingham conducted in Ethiopia observed a small subset of people with hookworm infections were half as likely to experience asthma or hay fever. Potential benefits have also been hypothesized in cases of multiple sclerosis, Crohn's Disease and diabetes.

Some research conducted has shown favourable results using hookworms to treat coeliac disease. Though research points to anti-allergenic properties associated with hook worm infections, the FDA does not currently recognize hookworms as a treatment.

In people with latent toxoplasmosis, the cysts are immune to these treatments, as the antibiotics do not reach the bradyzoites in sufficient concentration.

The medications prescribed for latent toxoplasmosis are:

- Atovaquone — an antibiotic that has been used to kill "Toxoplasma" cysts inside AIDS patients

- Clindamycin — an antibiotic that, in combination with atovaquone, seemed to optimally kill cysts in mice

There is a negative association between an infection with the parasite "T. gondii" and multiple sclerosis, therefore, researchers have concluded that toxoplasmosis infection could be considered a protective factor.

The preventative measure of keeping cats inside in areas with high infection rates can prevent infection. Approved tick treatments for cats can be used but have been shown not to fully prevent tick bites.

The most often used treatments for cytauxzoonosis are imidocarb dipropionate and a combination of atovaquone and azithromycin. Although imidocarb has been used for years, it is not particularly effective. In a large study, only 25% of cats treated with this drug and supportive care survived. 60% of sick cats treated with supportive care and the combination of the anti-malarial drug atovaquone and the antibiotic azithromycin survived infection.

Quick referral to a veterinarian equipped to treat the disease may be beneficial. All infected cats require supportive care, including careful fluids, nutritional support, treatment for complications, and often blood transfusion.

Cats that survive the infection should be kept indoors as they can be persistent carriers after surviving infection and might indirectly infect other cats after being themselves bitten by a vector tick.

Paragonimiasis, or lung fluke uses cats as a reservoir and subsequently can transmit the infection to humans. Symptoms in cats have not been observed. There are over nine species of lung flukes that can be transmitted to humans from cats. The disease has been found in Asia, Africa, India, North, South and Central America. It is not uncommon and estimates of those infected are in the millions. Signs symptoms in humans are coughing up blood, migration of the flukes into other body organs including the central nervous system. There it can cause neurological symptoms such as headache, confusion, convulsions, vision problems, and bleeding in the brain. This infection in humans is sometimes mistaken for tuberculosis.

Onchocercosis has been associated with pet cats in a few cases.

Cats can harbor and transmit hookworms to people.

If complications of helminthiasis, such as intestinal obstruction occur, emergency surgery may be required. Patients who require non-emergency surgery, for instance for removal of worms from the biliary tree, can be pre-treated with the anthelmintic drug albendazole.

Various strategies targeting the mollusc and avian hosts of schistosomes, have been used by lakeside residents in recreational areas of North America to deal with outbreaks of swimmer's itch. In Michigan, for decades, authorities used copper sulfate as a molluscicide to reduce snail host populations and thereby the incidence of swimmer's itch. The results with this agent have been inconclusive, possibly because:

- Snails become tolerant

- Local water chemistry reduces the molluscicide's efficacy

- Local currents diffuse it

- Adjacent snail populations repopulate a treated area

More importantly, perhaps, copper sulfate is toxic to more than just molluscs, and the effects of its use on aquatic ecosystems are not well understood.

Another method targeting the snail host, mechanical disturbance of snail habitat, has been also tried in some areas of North America and Lake Annecy in France, with promising results. Some work in Michigan suggests that administering praziquantel to hatchling waterfowl can reduce local swimmer's itch rates in humans. Work on schistosomiasis showed that water-resistant topical applications of the common insect repellent DEET prevented schistosomes from penetrating the skin of mice. Public education of risk factors, a good alternative to the aforementioned interventionist strategies, can also reduce human exposure to cercariae.

While annual or semi-annual mass antihelminthic administration is a critical aspect of any public health intervention, many have begun to realize how unsustainable it is due to aspects such as poverty, high rates of re-infection, and diminished efficacy of drugs with repeated use. Current research, therefore, has focused on the development of a vaccine that could be integrated into existing control programs. The goal of vaccine development is not necessarily to create a vaccine with sterilizing immunity or complete protection against immunity. A vaccine that reduces the likelihood of vaccinated individuals developing severe infections and thus reduced blood and nutrient levels could still have a significant impact on the high burden of disease throughout the world.

Current research focuses on targeting two stages in the development of the worm: the larval stage and the adult stage. Research on larval antigens has focused on proteins that are members of the pathogenesis-related protein superfamily, "Ancylostoma" Secreted Proteins. Although they were first described in "Anyclostoma", these proteins have also been successfully isolated from the secreted product of "N. americanus". "N. americanus" ASP-2 (Na-ASP-2) is currently the leading larval-stage hookworm vaccine candidate. A randomized, double-blind, placebo-controlled study has already been performed; 36 healthy adults without a history of hookworm infection were given three intramuscular injections of three different concentrations of Na-ASP-2 and observed for six months after the final vaccination. The vaccine induced significant anti-Na-ASP-2 IgG and cellular immune responses. In addition, it was safe and produced no debilitating side effects. The vaccine is now in a phase one trial; healthy adult volunteers with documented evidence of previous infection in Brazil are being given the same dose concentration on the same schedule used in the initial study. If this study is successful, the next step would be to conduct a phase two trial to assess the rate and intensity of hookworm infection among vaccinated persons. Because the Na-ASP-2 vaccine only targets the larval stage, it is critical that all subjects enrolled in the study be treated with antihelminthic drugs to eliminate adult worms prior to vaccination.

Adult hookworm antigens have also been identified as potential candidates for vaccines. When adult worms attach to the intestinal mucosa of the human host, erythrocytes are ruptured in the worm’s digestive tract which causes the release of free hemoglobin which is subsequently degraded by a proteolytic cascade. Several of these proteins that are responsible for this proteolytic cascade are also essential for the worm’s nutrition and survival. Therefore, a vaccine that could induce antibodies for these antigens could interfere with the hookworm’s digestive pathway and impair the worm’s survival. Three proteins have been identified: the aspartic protease-hemoglobinase APR-1, the cysteine protease-hemoglobinase CP-2, and a glutathione S-transferase.

There are two drugs available, praziquantel and oxamniquine, for the treatment of schistosomiasis. They are considered equivalent in relation to efficacy against "S. mansoni" and safety. Because of praziquantel's lower cost per treatment, and oxaminiquine's lack of efficacy against the urogenital form of the disease caused by "S. haematobium", in general praziquantel is considered the first option for treatment. The treatment objective is to cure the disease and to prevent the evolution of the acute to the chronic form of the disease. All cases of suspected schistosomiasis should be treated regardless of presentation because the adult parasite can live in the host for years.

Schistosomiasis is treatable by taking by mouth a single dose of the drug praziquantel annually.

The WHO has developed guidelines for community treatment based on the impact the disease has on children in villages in which it is common:

- When a village reports more than 50 percent of children have blood in their urine, everyone in the village receives treatment.

- When 20 to 50 percent of children have bloody urine, only school-age children are treated.

- When fewer than 20 percent of children have symptoms, mass treatment is not implemented.

Other possible treatments include a combination of praziquantel with metrifonate, artesunate, or mefloquine. A Cochrane review found tentative evidence that when used alone, metrifonate was as effective as praziquantel.

Another agent, mefloquine, which has previously been used to treat and prevent malaria, was recognised in 2008–2009 to be effective against "Schistosoma".

Experimental infection in immunocompetent and immunocompromised mice has produced intestinal inflammation, altered bowel habits, lethargy and death. Chronic diarrhea has been reported in non-human higher primates.

For many years from the 1950s onwards, vast dams and irrigation schemes were constructed, causing a massive rise in water-borne infections from schistosomiasis. The detailed specifications laid out in various UN documents since the 1950s could have minimized this problem. Irrigation schemes can be designed to make it hard for the snails to colonize the water and to reduce the contact with the local population. Even though guidelines on how to design these schemes to minimise the spread of the disease had been published years before, the designers were unaware of them. The dams appear to have reduced the population of the large migratory prawn "Macrobrachium". After the construction of fourteen large dams, greater increases in schistosomiasis occurred in the historical habitats of native prawns than in other areas. Further, at the 1986 Diama Dam on the Senegal River, restoring prawns upstream of the dam reduced both snail density and the human schistosomiasis reinfection rate.

Amphistomiasis in farm and wild mammals is due to infection of paramphistomes, such as the species of "Paramphistomum", "Calicophoron", "Cotylophoron", "Pseudophisthodiscus", etc. These are essentially rumen flukes, of which "Paramphistomum cervi" is the most notorious in terms of prevalence and pathogenicity. Infection occurs through ingestion of contaminated vegetables and raw meat, in which the viable infective metacercaria are deposited from snails, which are the intermediate hosts. The immature flukes are responsible for destroying the mucosal walls of the alimentary tract on their way to growing into adults. It is by this fervent tissue obliteration that the clinical symptoms are manifested. The adult flukes, on the other hand, are quite harmless, as they merely prepare for reproduction.

The zoonotic infection in human is caused by "G. discoides" and "W. watsoni" which are essentially intestinal flukes. The disease due to "G. discoides" is more specifically termed gastrodiscoidiasis. In their natural hosts such as pigs and monkeys, their infection in asymptomatic, but human infection is prevalent, by which they cause serious health problems, characterised by diarrhoea, fever, abdominal pain, colic, and an increased mucous production. In extreme situations such as in Assam, India, a number of mortality among children is attributed to this disease.

There is a lack of scientific study to support the efficacy of any particular treatment. An additional review published in 2009 made a similar conclusion, noting that because the diagnostics in use have been unreliable, it has been impossible to determine whether a drug has eradicated the infection, or just made the patient feel better. Historical reports, such as one from 1916, note difficulty associated with eradication of "Blastocystis" from patients, describing it as "an infection that is hard to get rid of."

A 1999 "in vitro" study from Pakistan found 40% of isolates are resistant to common antiprotozoal drugs. A study of isolates from patients diagnosed with IBS found 40% of isolates resistant to metronidazole and 32% resistant to furazolidone. Drugs reported in studies to be effective in eradicating "Blastocystis" infection have included metronidazole, trimethoprim, TMP-SMX (only trimethoprim is active with sulphamethoxazole demonstrating no activity), tetracycline, doxycycline, nitazoxanide, pentamidine, paromomycin and iodoquinol. Iodoquinol has been found to be less effective in practice than in-vitro. Miconazole and quinacrine have been reported as effective agents against "Blastocystis" growth in-vitro. Rifaximin, and albendazole have shown promise as has ivermectin which demonstrated high effectiveness against blastocystis hominis isolates in an in vitro study. There is also evidence that the probiotic yeast "Saccharomyces boulardii", and the plant mallotus oppositifolius may be effective against "Blastocystis" infections.

Physicians have described the successful use of a variety of discontinued antiprotozoals in treatment of "Blastocystis" infection. Emetine was reported as successful in cases in early 20th century with British soldiers who contracted "Blastocystis" infection while serving in Egypt. "In vitro" testing showed emetine was more effective than metronidazole or furazolidone. Emetine is available in the United States through special arrangement with the Center for Disease Control. Clioquinol (Entero-vioform) was noted as successful in treatment of "Blastocystis" infection but removed from the market following an adverse event in Japan. Stovarsol and Narsenol, two arsenic-based antiprotozoals, were reported to be effective against the infection. Carbarsone was available as an anti-infective compound in the United States as late as 1991, and was suggested as a possible treatment. The reduction in the availability of antiprotozoal drugs has been noted as a complicating factor in treatment of other protozoal infections. For example, in Australia, production of diloxanide furoate ended in 2003, paromomycin is available under special access provisions, and the availability of iodoquinol is limited.

There are 21.4 million people infected with trachoma, of whom 2.2 million are partially blind and 1.2 million are blind. It is found in Africa, Asia, Central and South America, Middle East, and Australia. The disease disproportionately affects women and children. The mortality risk is very low, although multiple re-infections eventually lead to blindness. The symptoms are internally scarred eyelids, followed by eyelids turning inward. Trachoma is caused by a micro-organism that spreads through eye discharges (on hands, cloth, etc.) and by "eye-seeking flies".

It is treated with antibiotics. The only known prevention method is interpersonal hygiene.

Snakebite was added to the list in 2017, after years of criticism of the WHO by activists for not making it a priority. The greatest burden of snakebite morbidity is in India and Southeast Asia. Globally, there are an estimated 421,000 envenomings each year (about 1 in 4 snakebites) and 20,000 deaths, but snakebites often go unreported.

Concomitant pinworm infection should also be excluded, although the association has not been proven. Successful treatment of the infection with iodoquinol, doxycycline, metronidazole, paromomycin, and secnidazole has been reported. Resistance requires the use of combination therapy to eradicate the organism. All persons living in the same residence should be screened for "D. fragilis", as asymptomatic carriers may provide a source of repeated infection. Paromomycin is an effective prophylactic for travellers who will encounter poor sanitation and unsafe drinking water.

Parasitic pneumonia is an infection of the lungs by parasites. It is a rare cause of pneumonia, occurring almost exclusively in immunocompromised persons (persons with a weakened or absent immune system). This is a respiratory infection that may or may not be serious.

There are a variety of parasites which can affect the lungs. In general, these parasites enter the body through the skin or by being swallowed. Once inside the body, these parasites travel to the lungs, most often through the blood. There, a similar combination of cellular destruction and immune response causes disruption of oxygen transportation. Depending on the type of parasite, antihelmynthic drugs can be prescribed.

The most common parasites involved:

- Ascariasis

- Schistosoma

- Toxoplasma gondii

Dientamoebiasis is a medical condition caused by infection with "Dientamoeba fragilis", a single-cell parasite that infects the lower gastrointestinal tract of humans. It is an important cause of traveler's diarrhea, chronic abdominal pain, chronic fatigue, and failure to thrive in children.

"Cytauxzoon felis" belongs to the order Piroplasmida and the family Theileriidae. "C. felis" is related to "Theileria spp". of African ungulates. It is not a bacterium, not a virus, and not a fungus but is instead a protozoan that infects the blood cells of cats.

Humans usually become infected after swimming in lakes or other bodies of slow-moving fresh water. Some laboratory evidence indicates snails shed cercariae most intensely in the morning and on sunny days, and exposure to water in these conditions may therefore increase risk. Duration of swimming is positively correlated with increased risk of infection in Europe and North America, and shallow inshore waters may harbour higher densities of cercariae than open waters offshore. Onshore winds are thought to cause cercariae to accumulate along shorelines. Studies of infested lakes and outbreaks in Europe and North America have found cases where infection risk appears to be evenly distributed around the margins of water bodies as well as instances where risk increases in endemic swimmer's itch "hotspots". Children may become infected more frequently and more intensely than adults but this probably reflects their tendency to swim for longer periods inshore, where cercariae also concentrate. Stimuli for cercarial penetration into host skin include unsaturated fatty acids, such as linoleic and linolenic acids. These substances occur naturally in human skin and are found in sun lotions and creams based on plant oils.