Diseases & Conditions

Research to understand and treat some of the world's most problematic diseases.

37 Results


Asthma is a chronic lung disease characterized by episodes of airway narrowing and obstruction, causing wheezing, coughing, chest tightness and shortness of breath.

Photo of a smog covered city scape

Autoimmune Diseases

More than 80 diseases occur as a result of the immune system attacking the body’s own organs, tissues, and cells. Some of the more common autoimmune diseases include type 1 diabetes, rheumatoid arthritis, systemic lupus erythematosus, and inflammatory bowel disease. Treatments are available for many autoimmune diseases, but cures have yet to be discovered.

Human T cell

Autoimmune Lymphoproliferative Syndrome (ALPS)

Autoimmune lymphoproliferative syndrome (ALPS) is a rare genetic disorder of the immune system first described by NIH scientists in the mid-1990s that affects both children and adults. In ALPS, unusually high numbers of white blood cells called lymphocytes accumulate in the lymph nodes, liver, and spleen and can lead to enlargement of these organs.

Autoimmune Lymphoproliferative Syndrome (ALPS)


Cholera is an acute, diarrheal illness caused by infection of the intestine with the bacterium Vibrio cholerae. An estimated 3-5 million cases and over 100,000 deaths occur each year around the world. The infection is often mild or without symptoms, but can sometimes be severe. Without treatment, death can occur within hours.

Image of cholera


Coronaviruses are a large family of viruses that usually cause mild to moderate upper-respiratory tract illnesses, like the common cold. However, three coronaviruses have caused more serious and fatal disease in people: SARS coronavirus (SARS-CoV), MERS coronavirus (MERS-CoV), and SARS-CoV-2 (which causes COVID-19).

MERS virus cells

Dengue Fever

Dengue fever is an infectious disease carried by mosquitoes and caused by any of four related dengue viruses. This disease used to be called "break-bone" fever because it sometimes causes severe joint and muscle pain that feels like bones are breaking. Health experts have known about dengue fever for more than 200 years. 

Aedes aegypti mosquito larvae

E. coli

Escherichia coli (E. coli) bacteria live in the intestines of people and animals, and are key to a healthy intestinal tract. Most E. coli strains are harmless, but some can cause diarrhea through contact with contaminated food or water while other strains can cause urinary tract infections, respiratory illness and pneumonia.

Image of E. coli bacteria

Ebola & Marburg

Ebola is a serious and often fatal illness caused by a virus. Several viruses can cause Ebola disease in humans, including Ebola virus and Sudan virus. Symptoms of Ebola include fever, headache, muscle pain, weakness, fatigue, diarrhea, vomiting, stomach pain, and severe bleeding and bruising.

Ebola virus particles both budding and attached to the surface of infected VERO E6 cells

Eczema (Atopic Dermatitis)

Atopic dermatitis, also known as eczema, is a non-contagious inflammatory skin condition. It is a chronic disease characterized by dry, itchy skin that can weep clear fluid when scratched. People with eczema also may be particularly susceptible to bacterial, viral, and fungal skin infections.

Image of eczema on skin

Food Allergy

NIAID is the lead institute at the National Institutes of Health conducting research on food allergy, a condition that affects approximately 8 percent of children and nearly 11 percent of adults in the United States. In a person with food allergy, the immune system reacts abnormally to a component of a food, sometimes producing a severe and life-threatening response.

Image of peanuts

Fungal Diseases

Fungi include a wide range of organisms, such as mushrooms, molds, and yeast, that are common outdoors in water, soil and air; indoors on surfaces; and on our skin and inside our bodies. Mold can worsen breathing problems in people with allergies or asthma, while various types of fungus can infect nails and cause skin rashes. 

Scanning electron micrograph of phagocytosis of a dead yeast particle (zymosan)


Gonorrhea is a sexually transmitted infection that can infect both men and women. Caused by Neisseria gonorrhoeae bacteria, gonorrhea can cause infections in the genitals, rectum and throat. Although treatable, drug-resistant forms of gonorrhea are increasing.

Neisseria gonorrhoeae bacteria

Group A Streptococcal Infections

Group A streptococcal (GAS) infections can range from a mild skin infection or a sore throat to severe, life-threatening conditions. Most people are familiar with strep throat, which along with minor skin infections, is the most common form of the disease.

NeutrophilScanning electron micrograph of Group A Streptococcus


Hepatitis is an inflammation of the liver. Viruses are the most common cause of hepatitis, but the condition can also be caused by other infections, heavy alcohol use, toxins, certain medications, and autoimmune disease. There are five main virus types that cause hepatitis---type A, B, C, D, and E.

Photo of liver tissue specimen extracted from a viral hepatitis patient.


HIV, or human immunodeficiency virus, is the virus that causes AIDS (acquired immunodeficiency syndrome) and can be transmitted during sexual intercourse; by sharing syringes; or perinatally during pregnancy, childbirth or breastfeeding. Since the first AIDS cases were reported in 1981, HIV/AIDS has been one of humanity’s deadliest and most persistent epidemics. Although extraordinary progress has been made in the fight against new HIV cases and AIDS deaths, the HIV pandemic continues.

Image of an HIV-infected T cell


Seasonal influenza, or flu, is a highly contagious respiratory disease caused by any of several human influenza viruses that circulate globally and cause annual outbreaks of varying severity. Influenza viruses infect the nose, throat, and lungs and produce symptoms that include sudden fever, extreme fatigue, coughing, chills, and muscle aches. Serious complications include pneumonia. Each year, flu causes millions of illnesses worldwide and kills many thousands. It is especially dangerous for people who are very young or old or who have other conditions such as heart disease or asthma. 

H1N1 Influenza Virus Particles


Leishmaniasis is a parasitic disease transmitted by the bites of infected sand flies. It is found in nearly 88 countries, from rain forests in Central and South America to deserts in the Middle East and west Asia. Some cases of the disease have also appeared in Mexico and Texas. The disease takes several different forms, including the most common cutaneous leishmaniasis, which causes skin lesions, and the more severe visceral leishmaniasis (also known as kala azar), which affects internal organs such as the spleen, liver, and bone marrow.

Leishmaniasis hero image

Leprosy (Hansen's Disease)

Leprosy (Hansen's Disease) is a chronic infectious disease that primarily affects the peripheral nerves, skin, upper respiratory tract, eyes, and nasal mucosa (lining of the nose). The disease is caused by a bacillus (rod-shaped) bacterium known as Mycobacterium leprae.

Leprosy micrograph

Lyme Disease

Lyme disease, or borreliosis, is caused by the bacterium Borrelia burgdorferi and is transmitted to humans through the bite of an infected blacklegged deer tick. It is the most common tickborne infectious disease in the United States.  

Lyme Disease Bacteria, Borrelia burgdorferi


Malaria is a mosquito-borne infectious disease caused by the bite of female Anopheles mosquitoes, which spread infectious Plasmodium parasites into a host. The WHO estimates that in 2020 about 240 million people had malaria and about 627,000 of them died. A vaccine to prevent malaria is available; however, its variable efficacy underscores the need for new interventions.

Malaria Infected Blood Cell

Mpox (formerly Monkeypox)

The monkeypox virus is part of the Orthopoxvirus genus, which also includes variola virus (the cause of smallpox), vaccinia virus, and cowpox virus. Although monkeypox is similar to smallpox, it is much less deadly. Initial symptoms of monkeypox infection include: fever, headache and body aches, fatigue, and swollen lymph nodes, followed by a rash of lesions on the skin. Human-to-human transmission of monkeypox occurs through direct contact with body fluids, lesions, prolonged face-to-face contact, and indirect contact with contaminated clothing or bedding. Animal-to-human transmission can occur through a bite or scratch, preparation of wild game, or direct or indirect contact with body fluids or lesions.

mpox particles in an infected cell.

Pertussis (Whooping Cough)

Pertussis, also known as whooping cough, is a highly contagious respiratory disease. It is caused by the bacterium Bordetella pertussis. Pertussis is known for uncontrollable, violent coughing that often makes it hard to breathe. After fits of many coughs, someone with pertussis often needs to take deep breaths, which result in a “whooping” sound.

Pertussis (bordetella pertussis) bacteria


Plague, caused by the bacterium Yersinia pestis, is a disease that affects humans and other mammals. People typically get infected after being bitten by a rodent flea that is carrying the bacterium or by handling a plague-infected animal. Antibiotics effectively treat plague. Without prompt treatment, plague can cause serious illness or death.

Scanning electron micrograph showing Yersinia pestis, which causes bubonic plague

Primary Immune Deficiency Diseases (PIDDs)

Primary immune deficiency diseases (PIDDs) are rare, genetic disorders that impair the immune system. Without a functional immune response, people with PIDDs may be subject to chronic, debilitating infections which can increase the risk of developing cancer. Some PIDDs can be fatal.

Primary Immune Deficiency Diseases (PIDDs)

Prion Diseases

Prion diseases are transmissible, untreatable, and fatal brain diseases of mammals. Their cause is highly unusual, and prion disease symptoms reflect the brain being destroyed. NIAID is exploring similarities between prion diseases and other protein misfolding diseases, such as Alzheimer’s and Parkinson’s diseases.

Prion protein fibrils