A scientist in a mask holding what appears to be a slide of a smear sample under a microscope.

Infections and infectious diseases

Infectious diseases arise as a result of infection with a pathogen. Depending on the type of pathogen, infections can be divided into four types: bacterial, viral, mycotic, and protozoan. Mycotic infection means “caused by fungi”. Protozoan infections involve infection with single-celled parasites. This type of disease includes malaria, for example


Most people experience warts at some stage of their lives. Warts are contagious and often very persistent. Children and adolescents are at the highest risk of developing warts.

Long COVID – long-term effects of COVID-19

Long COVID refers to health issues that persist or occur weeks or months after an acute COVID-19 infection. Common symptoms include a loss of stamina and fatigue.

COVID-19 (coronavirus disease 2019)

COVID-19 is caused by an infection with SARS‑CoV‑2. The disease may be mild or very severe. Vaccinations and medication help prevent people from developing a severe form.

Dengue fever

Dengue fever originated as a tropical disease that is transmitted by a mosquito bite. Since recovery is a lengthy process, travelers should take sufficient measures to protect themselves.

Styes and chalazia (eyelid inflammation)

Styes and chalazia: what is eyelid inflammation and how does it progress? Learn more about the symptoms, causes, and treatment.


Acute tonsillitis is accompanied by a sore throat and fever. Recurring tonsillitis in short intervals can be very strenuous.


Typical signs of conjunctivitis are eyelids that stick together and an itching and burning sensation in the eyes. It can be caused by viruses or bacteria, but can also have other causes.


Typical symptoms of acute gastritis are stomachache, feeling full, bloating, gas and heartburn. In most cases, gastritis is caused by a bacterial infection or the use of certain pain medication.

Molluscum contagiosum

Molluscum contagiosum is a virus causing small, wart-like papules (spots). It is a viral infection of the skin that mainly affects children.

Three-day fever

Three-day fever is a childhood illness involving a high temperature followed by a rash. The viral infection is usually harmless.


Someone who suffers from sinusitis has, for example, a blocked nose and a feeling of pressure in the forehead or jaw.


Pneumonia typically brings on a sudden high fever, coughing and breathlessness. People without any pre-existing conditions normally recover after a few weeks.


Sepsis, also known as blood poisoning, is an uncontrolled inflammatory reaction of the body to infections. It needs to be treated very quickly in hospital.


Shingles (herpes zoster) is a painful viral skin condition. The viruses attack nerves and cause an inflammation that spreads over the skin.


Scabies develops as a result of a mite infestation in the skin. Severe itching is typical. Scabies is contagious with extended skin contact. However, the disease can be well treated.


Chlamydia are bacteria that cause sexually transmitted diseases and frequently go unnoticed.


The HIV virus infects immune cells and weakens the immune system. The serious illnesses caused by HIV are called AIDS.

Acute bronchitis

With acute bronchitis, the lower airways (bronchi) become temporarily inflamed. Initially, there is a dry cough but phlegm may later be coughed up from the airways.

Acute middle ear infection

Middle ear infections are one of the most common illnesses among small children. Children with an infection cry often and complain of pain.

Cystitis (urinary tract infection)

Women are most likely to get urinary tract infections. Cystitis is caused by bacteria and can usually be treated effectively. A burning pain when passing urine is typical.

Athlete’s foot

Athlete’s foot (tinea pedis) can redden or crack the skin and cause itchiness. It can usually be effectively treated with creams from a pharmacy. Keeping the feet dry is important with athlete’s foot.

Gastrointestinal infection by noroviruses

Symptoms of an infection with noroviruses are vomiting and diarrhea. An outbreak of this illness must be halted quickly.

Tick-borne encephalitis (TBE)

Tick-borne encephalitis (TBE) is a viral infection transmitted ticks.

Boils and carbuncles

Boils (furuncles), carbuncles, abscesses and pimples are all linked to inflamed skin but differ slightly. Medical treatment is often useful for boils.


Impetigo (impetigo contagiosa) is an itchy and sometimes painful infection of the skin. It is especially common in young children.

Seborrheic dermatitis

Seborrheic dermatitis is a non-contagious inflammation of the skin. It causes red patches and oily flakes to form on the skin, especially on the face and scalp.


Diarrheal diseases occur often. They are often the result of a viral infection. Persistent diarrhea must be treated because it can lead to loss of fluid and sodium depletion.


Rabies is a zoonotic disease, i.e. a disease transmitted from animals to humans. It is usually caused by lyssaviruses, a family of viruses that includes the classic rabies virus.

COVID-19, cold, flu – symptoms at a glance

Learn about the typical symptoms of the three illnesses, what people can do if they experience any of these and how they can protect themselves against infection.

Bubonic plague

The bubonic plague has spread fear and terror over the centuries. Although the disease has now become rare, no one has managed to eradicate it.

Ebola virus disease

Discover where Ebola virus disease most commonly occurs, its usual symptoms and how it can be prevented.

Pneumonic plague

It is true that the plague is now rare, but it has not been completely eradicated. Pneumonic plague may occur on its own or as a result of bubonic plague.


Malaria is an infectious disease that is spread by the Anopheles mosquito. In Germany, a few hundred cases of the disease brought back by travelers are registered each year.

High temperature in children

High temperatures are common in children and their causes are usually harmless. Only rarely is a high temperature an indication of a serious condition that requires medical treatment.


If the glans (the head of the penis) becomes red and painful, this may be due to an inflammation. Inflammation of the glans is known as balanitis and is often caused by a yeast infection.


Diphtheria is a life-threatening infection caused by corynebacteria. There is nose, throat, larynx, skin, or wound diphtheria, as well as toxic diphtheria.

Fungal nail infection

Fungal nail infections are usually caused by an infection with skin fungi. They often affect the big toenails, which become brittle and discolored. Fungal nail infections rarely go on their own.

Chronic wounds

Wounds do not always heal quickly. Many take a long time to heal or keep opening up. They are referred to as chronic open wounds.


Rubella poses a risk to pregnant women and their unborn babies. There is a vaccine that protects against this viral disease.

Typhoid and paratyphoid

Typhoid is caused by bacteria in contaminated drinking water and food. It is recommended that people get a typhoid vaccine before travel to high-risk areas and take care with food and drink.


Measles is a viral infection with symptoms such as fever, skin rash, and possible serious complications. A vaccination against the infection offers protection.

Lyme disease

Tick bites do not usually cause any complications. But some ticks transfer Lyme disease to humans. Lyme disease is usually treated with antibiotics.

Flu (influenza)

Many people confuse the flu with the common cold. Despite having similar symptoms, these two infections may develop differently. Flu begins suddenly, causing the sufferer to quickly feel very unwell.

Middle East Respiratory Syndrome (MERS)

MERS is a viral infection of the respiratory tract, which occurs predominantly on the Arabian Peninsula. The virus is mainly transmitted from dromedary camels to humans.

Pubic lice

Pubic lice are transmitted by physical proximity, particularly through sexual contact. Their bites cause bad itching in hirsute parts of the body. Here you can read what can be done about them.

Zika virus infection

Zika virus is mainly found in tropical countries. While it produces a mild infection, it can cause serious birth defects if it occurs during pregnancy.

Encephalitis (inflammation of the brain)

Encephalitis is an inflammation of the brain. It can have several causes, the most frequent being viruses.


Meningitis is the inflammation of the meninges. This can have multiple causes. If triggered by bacteria, meningitis can quickly become life-threatening.

Bacterial vaginosis

Bacterial vaginosis often has no symptoms. It sometimes causes a grayish-white discharge with a fishy odor. If symptoms occur, they can be treated successfully.

Pityriasis versicolor (tinea versicolor)

With pityriasis versicolor, round or oval patches develop on the skin, in particular on the neck, back, arms and chest. The rash is usually harmless and easily treated.

West Nile fever

West Nile fever is a viral infection transmitted by mosquitoes. It primarily occurs in warmer countries, but now also in Germany.

Yellow fever

Yellow fever is a tropical disease caused by a virus that occurs in Africa and South America. It is transmitted by mosquitoes. Travelers can protect themselves by getting a vaccine.

Swine flu

Flu is a common respiratory infection in pigs, caused by influenza viruses that occur primarily in these animals. In rare cases, people can become infected and ill as a result.

Endocarditis (inflammation of the lining of the heart)

Endocarditis is an inflammation of the inner lining of the heart. Early treatment is important to avoid complications.

Inflammation of the eardrum

An acute inflammation of the eardrum (myringitis) is caused by viruses and bacteria. Earache is a common symptom. A chronic inflammation often causes no pain.


Listeriosis is a bacterial infection caused by consuming contaminated food. Most cases are mild. However, some people may become seriously ill and can even die from listeriosis.

EHEC infections

Most infections with the EHEC bacteria come from contaminated food or traces of animal feces. EHEC can cause watery and bloody diarrhea and in some cases acute kidney failure.

Rheumatic heart disease

Auslöser der rheumatischen Herzkrankheit sind Streptokokken. Diese Bakterien verursachen akute Atemwegsinfektionen. In response, the immune system creates antibodies that may also attack and damage the heart.

Severe acute respiratory syndrome (SARS)

SARS is an infectious disease of the lungs, which is caused by the SARS-CoV coronavirus. The virus first appeared at the end of 2002 and spread to more than 30 countries until the middle of 2003.

Bird flu (avian influenza)

Bird flu (avian influenza) primarily affects birds but can also be transmitted to humans through close contact with infected birds. Infection is rare but often has severe symptoms.

Acute myocarditis

Acute myocarditis (inflammation of the heart muscle) can be a rare consequence of an infection. There are mild but also life-threatening forms.

Clostridioides (Clostridium) difficile infection

Clostridioides (Clostridium) difficile bacteria can cause intestinal inflammation and diarrhea. The condition is usually triggered by taking antibiotics.

Acute appendicitis

Acute appendicitis is accompanied by severe abdominal pain and usually requires surgery. A possible complication is a ruptured appendix, which can be life-threatening.

Prostatitis and pelvic pain syndrome

Inflammation of the prostate can have a range of causes. In some cases, it is triggered by bacteria. Typical symptoms include pain and difficulties urinating.

Glandular fever

Glandular fever is an infectious disease that is triggered by certain herpes viruses. It is usually transmitted in saliva. Hygiene measures are essential to prevention.

Inflammation of the epiglottis (epiglottitis)

Inflammation of the epiglottis is usually caused by bacteria. Immediate treatment is required, as it can cause acute shortness of breath.


The skin rash that typically occurs with ringworm (tinea corporis) has a ring-like appearance. It usually clears up quickly if treated with an anti-fungal skin cream.

Polio (poliomyelitis)

Polio (poliomyelitis) can cause permanent paralysis. Polio viruses have been almost eradicated thanks to large-scale vaccination campaigns. Unvaccinated children and adults can contract polio.

Duodenal ulcer

An ulcer in the duodenum usually occurs as a result of regular use of certain pain medication or infection with specific bacteria. These ulcers are normally easy to treat.

Gastric ulcer

A gastric ulcer usually occurs as a result of an infection with certain bacteria or due to long-term use of certain drugs for pain relief. Gastric ulcers are normally easy to treat.

Bacterial throat infection (pharyngitis)

A throat infection (pharyngitis) is usually caused by viruses. However, it can also be caused by bacteria, such as Streptococcus bacteria. This is known as streptococcal pharyngitis (strep throat).

Pinworms (enterobiasis)

Pinworm infection is one of the most common human worm conditions. It is usually harmless, and it typically becomes apparent due to itching around the anus.

Fifth disease

Fifth disease is one of the most common viral illnesses in children. Most adults are immune to it. Pregnant women who do not have immunity can pass the virus on to their unborn child.

Genital herpes

Genital herpes is one of the most common sexually transmitted infections (STI). It is triggered by herpes simplex viruses. The risk of becoming infected can be reduced through certain measures.

Oral herpes (cold sores)

With oral herpes, particular herpes viruses cause painful blisters known as cold sores to form. The condition heals on its own in 1 to 2 weeks. No treatment is normally required.


Intertrigo is a rash that appears in the skin folds as a result of moisture and chafing. In many cases, the affected areas also become infected with yeast fungi.

Legionnaires’ disease

Legionnaires’ disease (legionellosis) is a respiratory disease caused by bacteria. It may or may not be accompanied by pneumonia. The source of infection is contamination of the water supply.


Mumps is a viral infection that affects not only children. Learn more about this contagious infection and how to prevent contraction.


Anthrax is a rare disease. It is transmitted to humans by animals. Certain occupational groups are at high risk of contracting the disease. Read more about symptoms, causes, and treatment.

Campylobacter infection

Campylobacter infection is an infectious disease with a high temperature and diarrhea. It is generally caused by eating contaminated food of animal origin.


Salmonellosis is an infection caused by bacteria in food. The main symptom is diarrhea. It may be accompanied by abdominal pain, nausea and vomiting.


Toxoplasmosis is caused by the parasite Toxoplasma gondii. A third of all people are carriers, but only around 5% of them show symptoms of the disease.


Syphilis is a globally prevalent contagious disease that infects people through sexual intercourse in particular. Learn more about symptoms, prevention, and treatment.


Gonorrhea is a sexually transmitted infection with the Neisseria gonorrhoeae (gonococcus) bacterium which is found worldwide. Find out more about symptoms, prevention, and therapy.


Tetanus is a dangerous infectious disease. Even a small wound can be the portal of entry for the pathogen. People can protect themselves from it with vaccination.

Hantavirus infections

Hantaviruses cause a flu-like illness with fever. It often also affects the kidneys. Rodents such as rats and mice and their droppings are carriers of the virus.


Leprosy is a bacterial infectious disease that primarily occurs in South East Asia, South America, and Africa. Though leprosy is curable, there are still serious outcomes.

Scarlet fever

Scarlet fever bacteria (streptococci) cause an illness in children with symptoms such as a high fever, sore throat, and typical skin rash.

Whooping cough (pertussis)

Whooping cough is a highly infectious communicable disease that is triggered by bacteria. The disease can put severe stress on the body and is lengthy.

Tuberculosis (TB)

Tuberculosis (TB) is a bacterial infectious disease most commonly affecting the lungs. It is relatively rare in Germany.

Hepatitis C

Hepatitis C is a viral infection of the liver transmitted through blood and, over time, can lead to severe liver damage. But these days this can almost always be avoided with medication.

Common cold

The first signs of a common colds are often sneezing and a sore throat. If rhinitis has fully kicked in, many people feel weak and ill.

False croup

False croup is a condition in the airways. It usually occurs in small children. Typical symptoms include a barking cough, a rasping sound when breathing in, and a slight shortness of breath.

Oral thrush (oral candidiasis)

If a person's mouth constantly feels furry, it may be caused by oral thrush. It is rarely dangerous, but often unpleasant.

Vaginal yeast infection

Fungal infections of the vagina occur frequently in women of childbearing age. They often require only brief treatment with vaginal suppositories or creams.

Chickenpox (varicella)

Typical signs of chickenpox are an extremely itchy skin rash with red blisters and a slight fever. This viral infection most frequently affects children between the ages of 2 and 10.

Erysipelas and cellulitis

Erysipelas and cellulitis are caused by bacteria that break through the skin barrier due to an injury. With prompt treatment, a complete recovery is usually possible.

Hepatitis A

Hepatitis A is an infectious disease often brought back from traveling. The main symptom is liver inflammation. Find out more about symptoms, treatment, and vaccine protection.

Hepatitis B

Hepatitis B is a viral infection of the liver transmitted during unprotected sex, for example. Find out how the infection goes on to develop, what complications it has and who should be vaccinated.


Botulism is a type of poisoning caused by botulinum toxin, a neurotoxin produced by the bacterium Clostridium botulinum.

Infection with cytomegalovirus (CMV)

Cytomegalovirus infections (CMV) can be dangerous for the fetus, premature babies and people with immune deficiency.

Hand, foot and mouth disease (HFMD)

Hand, foot and mouth disease is an infectious disease that occurs sporadically worldwide. It most often affects infants and young children and is usually harmless.