Important: This page is general information, not medical advice. It does not recommend or prescribe any treatment. Always consult your doctor or pharmacist before starting, stopping or changing any medicine.
About Parasitic Diseases
Parasites are living things that use other living things - like your body - for food and a place to live. You can get them from contaminated food or water, a bug bite, or sexual contact. Some parasitic diseases are easily treated and some are not.
Parasites range in size from tiny, one-celled organisms called protozoa to worms that can be seen with the naked eye. Some parasitic diseases occur in the United States. Contaminated water supplies can lead to Giardia infections. Cats can transmit toxoplasmosis, which is dangerous for pregnant women. Others, like malaria, are common in other parts of the world.
If you are traveling, it's important to drink only water you know is safe. Prevention is especially important. There are no vaccines for parasitic diseases. Some medicines are available to treat parasitic infections.
It sits within Infections.
The lead U.S. institute for this subject is the National Institute of Allergy and Infectious Diseases.
When to speak to someone. Reading about a topic cannot tell you whether it applies to you. Speak to a doctor or pharmacist if symptoms are severe, sudden, getting worse, or simply not going away — and seek emergency care immediately for chest pain, breathing difficulty, sudden weakness or confusion, or a serious allergic reaction.
Research on Parasitic Diseases
2,308 studies areregistered for this condition on ClinicalTrials.gov, the U.S. National Library of Medicine's public registry. A selection is below — the links go straight to the registry entry, not to a summary of ours.
What a registered study does and does not mean. Registration means a study exists and has been declared publicly. It says nothing about whether the treatment being tested works, is safe, or is available to you. Many studies find no benefit — that is what research is for. Never seek out an experimental treatment on the strength of a registry entry alone.
Research currently under way
- This is a Clinical Study to Assess Whether the Combination of SJ733 and Tafenoquine Will be a Safe and Rapidly Acting Anti-malarial for the Radical Cure of P. Vivax MalariaR. Kiplin Guy
- Induced Blood-Stage Malaria in Healthy Malaria-Naive Adults to Assess the Safety and Infectivity of Plasmodium Vivax Challenge Agent and Evaluate Transmission in Mosquito Feeding AssaysNational Institute of Allergy and Infectious Diseases (NIAID)
- Southeast Asia Dose Optimization of TafenoquineUniversity of Oxford
- Laboratory Evaluation of Pregnancy Malaria Vaccine Candidates/In-vitro Testing of Pregnancy Malaria Vaccine CandidatesNational Institute of Allergy and Infectious Diseases (NIAID)
- A Safety and Efficacy Study of Different Doses of Oxfendazole Compared to a Single Dose of Albendazole to Treat Trichuris Trichiura Infection in AdultsAsociacion Benefica Prisma
- Natural History of Treated Neurocysticercosis and Long-Term OutcomesNational Institute of Allergy and Infectious Diseases (NIAID)
Research already completed
- Preventing Malaria in School Children to Protect the Whole Community in Rural Blantyre District, MalawiLiverpool School of Tropical Medicine
- Randomised Clinical Trial in Treatment Modalities for Cutaneous Leishmaniasis Caused by Leishmania Tropica, in PakistanMedecins Sans Frontieres, Netherlands
- Triple Artemisinin-based Combination Therapy for Delaying Drug Resistance Development - a Randomized Clinical TrialMuhimbili University of Health and Allied Sciences
Study data from ClinicalTrials.gov, a service of the U.S. National Library of Medicine. Retrieved 2026-07-30. Registry entries are supplied by study sponsors and investigators; ClinicalTrials.gov does not verify their scientific validity. PocketsInfo is not affiliated with, and not endorsed by, the NLM or the NIH.
Where to read more
Rather than paraphrase, we point you to the primary sources. Every link below is to a government health agency, a national institute or a recognised medical body — grouped by what you are trying to find out.
Start Here
- About ParasitesCenters for Disease Control and Prevention
- Germs: Understand and Protect against Bacteria, Viruses, and InfectionsMayo Foundation for Medical Education and Research
- Parasites and Foodborne IllnessDepartment of Agriculture, Food Safety and Inspection Service
Diagnosis and Tests
- Diagnosis of Parasitic DiseasesCenters for Disease Control and Prevention
- Ova and Parasite TestNational Library of Medicine
- String test for intestinal parasitesMedical Encyclopedia
- Xylose TestingNational Library of Medicine
Prevention and Risk Factors
- Hand Hygiene Frequently Asked QuestionsCenters for Disease Control and Prevention
- Water Disinfection for TravelersCenters for Disease Control and Prevention
- What Causes Parasitic DiseasesCenters for Disease Control and Prevention
Related Issues
- Planning for Parasitic Diseases when TravellingCenters for Disease Control and Prevention
- Post-Travel Parasitic Disease Including Evaluation of EosinophiliaCenters for Disease Control and Prevention
Clinical Trials
- ClinicalTrials.gov: Lice InfestationsNational Institutes of Health
- ClinicalTrials.gov: Parasitic DiseasesNational Institutes of Health
Medical subject headings
Clinicians and researchers index this subject under Parasitic Diseases. These are the terms to use when searching medical literature.
This page is built from the MedlinePlus health topic record for Parasitic Diseases, a service of the U.S. National Library of Medicine (NLM), National Institutes of Health. Information is from MedlinePlus.gov. PocketsInfo is not affiliated with, and is not endorsed by, the NLM or the NIH. Retrieved 30 July 2026.