Ivermectin kills the parasite by interfering with the nervous system and muscle function, in particular, by enhancing inhibitory neurotransmission. The drug binds to and activates glutamate-gated chloride channels. These channels, present in neurons and myocytes, are not invertebrate-specific, but are protected in vertebrates from the action of ivermectin by the blood–brain barrier. Ivermectin is thought to irreversibly activate these channel receptors in the worm, eventually causing an inhibitory postsynaptic potential. The chance of a future action potential occurring in synapses between neurons decreases and the nematodes experience flaccid paralysis followed by death.

Ivermectin is directly effective against the larval stage microfilariae of "O. volvulus"; they are paralyzed and can be killed by eosinophils and macrophages. It does not kill adult females (macrofilariae), but does cause them to cease releasing microfilariae, perhaps by paralyzing the reproductive tract. Ivermectin is very effective in reducing microfilarial load and reducing number of punctate opacities in individuals with onchocerciasis.

For the treatment of individuals, doxycycline is used to kill the "Wolbachia" bacteria that live in adult worms. This adjunct therapy has been shown to significantly lower microfilarial loads in the host, and may kill the adult worms, due to the symbiotic relationship between "Wolbachia" and the worm. In four separate trials over 10 years with various dosing regimens of doxycycline for individualized treatment, doxycycline was found to be effective in sterilizing the female worms and reducing their numbers over a period of four to six weeks. Research on other antibiotics, such as rifampicin, has shown it to be effective in animal models at reducing "Wolbachia" both as an alternative and as an adjunct to doxycycline. However, doxycycline treatment requires daily dosing for at least four to six weeks, making it more difficult to administer in the affected areas.

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.

Treatments for lymphatic filariasis differ depending on the geographic location of the endemic area. In sub-Saharan Africa, albendazole is being used with ivermectin to treat the disease, whereas elsewhere in the world, albendazole is used with diethylcarbamazine. Geo-targeting treatments is part of a larger strategy to eventually eliminate lymphatic filariasis by 2020.

Additionally, surgical treatment may be helpful for issues related to scrotal elephantiasis and hydrocele. However, surgery is generally ineffective at correcting elephantiasis of the limbs. A vaccine is not yet available but in 2013 the University of Illinois was reporting 95% efficacity in testing against "B. malayi" in mice.

Treatment for podoconiosis consists of consistent shoe-wearing (to avoid contact with the irritant soil) and hygiene - daily soaking in water with an antiseptic (such as bleach) added, washing the feet and legs with soap and water, application of ointment, and in some cases, wearing elastic bandages. Antibiotics are used in cases of infection.

In 2015 William C. Campbell and Satoshi Ōmura were Co-awarded half of that year's Nobel prize in Physiology or Medicine for the discovery of the drug avermectin, which, in the further developed form ivermectin, has decreased the occurrence of lymphatic filariasis.

Filarial diseases in humans offer prospects for elimination by means of vermicidal treatment. If the human link in the chain of infection can be broken, then notionally the disease could be wiped out in a season. In practice it is not quite so simple, and there are complications in that multiple species overlap in certain regions and double infections are common. This creates difficulties for routine mass treatment because people with onchocerciasis in particular react badly to treatment for lymphatic filariasis.

Diethylcarbamazine has been shown as an effective prophylaxis for "Loa loa" infection.

A study of Peace Corps volunteers in the highly Loa—endemic Gabon, for example, had the following results: 6 of 20 individuals in a placebo group contracted the disease, compared to 0 of 16 in the DEC-treated group. Seropositivity for antifilarial IgG antibody was also much higher in the placebo group. The recommended prophylactic dose is 300 mg DEC given orally once weekly. The only associated symptom in the Peace Corps study was nausea.

Researchers believe that geo-mapping of appropriate habitat and human settlement patterns may, with the use of predictor variables such as forest, land cover, rainfall, temperature, and soil type, allow for estimation of Loa loa transmission in the absence of point-of-care diagnostic tests. In addition to geo-mapping and chemoprophylaxis, the same preventative strategies used for malaria should be undertaken to avoid contraction of loiasis. Specifically, DEET-containing insect repellent, permethrin-soaked clothing, and thick, long-sleeved and long-legged clothing ought to be worn to decrease susceptibility to the bite of the mango or deer fly vector. Because the vector is day-biting, mosquito (bed) nets do not increase protection against loiasis.

Vector elimination strategies are an interesting consideration. It has been shown that the "Chrysops" vector has a limited flying range, but vector elimination efforts are not common, likely because the insects bite outdoors and have a diverse, if not long, range, living in the forest and biting in the open, as mentioned in the vector section.

No vaccine has been developed for loiasis and there is little report on this possibility.

Treatment of loiasis involves chemotherapy or, in some cases, surgical removal of adult worms followed by systemic treatment. The current drug of choice for therapy is diethylcarbamazine (DEC), though ivermectin use is not unwarranted. The recommend dosage of DEC is 6 mg/kg/d taken three times daily for 12 days. The pediatric dose is the same. DEC is effective against microfilariae and somewhat effective against macrofilariae (adult worms).

In patients with high microfilaria load, however, treatment with DEC may be contraindicated, as the rapid microfilaricidal actions of the drug can provoke encephalopathy. In these cases, albendazole administration has proved helpful, and superior to ivermectin, which can also be risky despite its slower-acting microfilaricidal effects.

Management of "Loa loa" infection in some instances can involve surgery, though the timeframe during which surgical removal of the worm must be carried out is very short. A detailed surgical strategy to remove an adult worm is as follows (from a real case in New York City). The 2007 procedure to remove an adult worm from a male Gabonian immigrant employed proparacaine and povidone-iodine drops, a wire eyelid speculum, and 0.5 ml 2% lidocaine with epinephrine 1:100,000, injected superiorly. A 2-mm incision was made and the immobile worm was removed with forceps. Gatifloxacin drops and an eye-patch over ointment were utilized post surgery and there were no complications (unfortunately, the patient did not return for DEC therapy to manage the additional worm—and microfilariae—present in his body).

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.

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.

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.

Broad-spectrum benzimidazoles (such as albendazole and mebendazole) are the first line treatment of intestinal roundworm and tapeworm infections. Macrocyclic lactones (such as ivermectin) are effective against adult and migrating larval stages of nematodes. Praziquantel is the drug of choice for schistosomiasis, taeniasis, and most types of food-borne trematodiases. Oxamniquine is also widely used in mass deworming programmes. Pyrantel is commonly used for veterinary nematodiasis. Artemisinins and derivatives are proving to be candidates as drugs of choice for trematodiasis.

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.

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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There is no consensus on optimal therapeutic approach. The most commonly used drug is diethylcarbamazine (DEC), but it is, however, often ineffective. Although other drugs have been tried such as praziquantel, ivermectin, and albendozole, none has proven to be reliably and rapidly effective. Mebendazole appeared more active than DEC in eliminating the infection, and had comparable overall responses. Thiabendazole evidenced a small, but significant activity against the infection. A combination of treatments, DEC plus mebendazole, was much more effective than single drug doses.

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.

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.

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.

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.

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.

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.

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.

Each type of vertically transmitted infection has a different prognosis. The stage of the pregnancy at the time of infection also can change the effect on the newborn.

The Mazzotti reaction, first described in 1948, is a symptom complex seen in patients after undergoing treatment of onchocerciasis with the medication diethylcarbamazine (DEC). Mazzotti reactions can be life-threatening, and are characterized by fever, urticaria, swollen and tender lymph nodes, tachycardia, hypotension, arthralgias, oedema, and abdominal pain that occur within seven days of treatment of microfilariasis. The Mazzotti reaction correlates with intensity of infection; however, there are probably multiple infection intensity-dependent mechanisms responsible for mediating this complex reaction.

The phenomenon is so common when DEC is used for the treatment of onchocerciasis that this drug is the basis of a skin patch test used to confirm that diagnosis. The drug patch is placed on the skin, and if the patient is infected with the microfilaria of "O. volvulus", localized pruritus and urticaria are seen at the application site.

A case of the Mazzotti reaction has been reported after presumptive treatment of schistosomiasis and strongyloidiasis with ivermectin, praziquantel and albendazole. The patient had complete resolution of symptoms after intravenous therapy with methylprednisolone.

Some vertically transmitted infections, such as toxoplasmosis and syphilis, can be effectively treated with antibiotics if the mother is diagnosed early in her pregnancy. Many viral vertically transmitted infections have no effective treatment, but some, notably rubella and varicella-zoster, can be prevented by vaccinating the mother prior to pregnancy.

If the mother has active herpes simplex (as may be suggested by a pap test), delivery by Caesarean section can prevent the newborn from contact, and consequent infection, with this virus.

IgG antibody may play crucial role in prevention of intrauterine infections and extensive research is going on for developing IgG-based therapies for treatment and vaccination.