Infection is caused when pathogens enter a host. The pathogen that causes infection is often different from the pathogen that causes disease. In contrast, the symptoms of infection are similar to those of disease. Infection can be caused by bacteria, viruses, fungi, or parasites.
Endogenous infection occurs when a human pathogen is transferred from a person’s body to another person. The pathogen that causes endogenous infection is usually from the same genus or species as the pathogen that causes disease. Endogenous infection often occurs during human-to-human transmission of infectious diseases.
Endogenous infection occurs when:
- The pathogen is an organism that normally lives in the human body
- The person with the pathogen does not have symptoms or does not have an effective immune system
- The person with the pathogen is in close contact with another person who has the pathogen
It is rare for a pathogen to spread from one person to another.
Symptoms of endogenous infection
Endogenous infection is caused by one of the following:
- A virus that is transmitted from human to human
- A bacterium (bacteria that live in the human body)
- A fungus
- A parasite
Endogenous infections can cause a wide range of symptoms. The symptoms can vary from mild to severe. Symptoms can also vary by the type of infection, the location of the infection, and the age of the person.
The symptoms of endogenous infection can include:
- Muscle aches
- Sore throat
- Runny nose
- Chest pain
- Swollen lymph nodes
- Skin rash
Infection is often transmitted by close contact with an infected person. It can also be transmitted by sharing personal items.
Causes of endogenous infection
Endogenous infection is caused by one of four types of pathogens:
Viruses are often spread through human-to-human contact. They may cause a wide range of symptoms and vary in severity.
Viruses that cause infections that are spread from person to person include:
- Human immunodeficiency virus (HIV)
- Human herpesvirus 6 (HHV-6)
- Human parvovirus B19
- Human parvovirus B5
- Human adenovirus
- Human parainfluenza virus
- Human respiratory syncytial virus (RSV)
- Human parvovirus B3
Bacteria are usually spread through human-to-human contact.
Bacteria that cause infections that are spread from person to person include:
- Streptococcus pneumonia
- Mycoplasma pneumonia
- Listeria monocytogenes
Fungi are usually spread through human-to-human contact. They cause a wide range of illnesses and vary in severity.
Fungi that cause infections that are spread from person to person include:
- Aspergillus fumigatus
- Blastomyces dermatitidis
Parasites are usually transferred from person to person by direct or indirect contact. They are often spread by insect bites.
Parasites that cause infections that are spread from person to person include:
- Toxoplasma gondii
- Trypanosoma cruzi
- Giardia lamblia
- Toxocara canis
When to see a doctor?
If a person has signs and symptoms of infection, they should seek medical treatment.
A person with signs and symptoms that are mild should see a doctor.
If the person has signs and symptoms of infection and they are not treated, they could become very ill. It is important that the person seek medical treatment.
Some people may not have any signs or symptoms of infection. However, it is possible that they have an infection that is not detected. An infection may be transmitted by the bacteria that causes the infection. These bacteria are not detected by the immune system.
People who experience a sudden illness or have a severe illness, especially if they have a high fever, should seek medical care.
How is endogenous infection diagnosed?
A doctor will usually diagnose endogenous infection based on the person’s symptoms and their medical history.
Doctors may also test a blood sample for the type of pathogen that is causing the infection.
How is endogenous infection treated?
Treatment depends on the type of underlying infection.
People with viral infections that are caused by either a virus or a bacterium may recover completely.
People with symptoms that are mild and who do not have an underlying infection may not require medical treatment. However, they should seek medical care if they have:
- A high fever that does not improve
- A high fever that lasts for more than one day
- A high fever that is accompanied by severe chills
- Severe muscle pain or a stiff neck
People who experience a sudden illness or who have a severe illness should seek medical care.
Parasitic infections are treated with antimonials or other drugs with antiparasitic properties.
Invasive fungal infections
Medications for invasive fungal infections are usually antifungals. These include amphotericin B, itraconazole, voriconazole, or flucytosine.
People with a severe illness may require intravenous (IV) treatment.
People who have a rash and who have a high fever should seek medical care.
Other types of infection
People with other types of infections may also experience mild to moderate symptoms.
However, some people may develop more serious symptoms. They should seek medical attention if they have:
- Signs and symptoms that are severe or prolonged
- Signs and symptoms that are not improving
- Signs and symptoms that are not resolving within a few days
What is the long-term outlook?
The outlook for people with endogenous infection depends on the cause of the infection.
The outlook is good for people with viral infections that are caused by a virus that is spread from person to person.
The outlook is good for people with bacterial infections that are caused by a bacterium that is transmitted from person to person.
Endogenous infection occurs when an infection that is spread from person to person, such as a virus or a bacterium, causes an infection that is not detected by the immune system.
The signs and symptoms vary depending on the type of infection and its severity.
There is no treatment for endogenous infection, but symptoms may improve on their own.
People with mild symptoms may not require treatment. However, they should seek medical attention if they experience:
If a person has signs or symptoms of infection, they should seek medical attention
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