Persistence: how infections linger in the body

What is persistence

Persistence Persistence (from the Latin verb persisto - "to remain", "to stay constantly") is the ability of some infections to stay in the body for years or even decades, despite taking medications and other therapy.

Scientists call the presence of such persistent pathogens persistent Persistant Viral Infections.

Often a virus or microbe capable of persistence does not manifest itself at all for a long time. That is, it seems to a person that the disease has receded. But there is a pathogen in the body and at any moment it can remind of its existence with a new outbreak of the disease.

Where does persistence come from

Scientists are still only studying this issue. It is assumed that some Persistent bacterial infections and persister cells and Anatomy of Viral Persistence viruses have some adaptive mechanisms that allow them to quickly adapt to the effects of drugs, as well as hide from the immune system.

Professor of medical sciences, infectious disease specialist William Petrie, in a column for The Conversation, spoke about one such mechanism, which is used, in particular, by viruses.

William Petrie Infectionist

There are several places in the body that are poorly accessible for the immune system. These include the central nervous system, eyes, testes in men. It is very difficult to eradicate an infection that has settled there, the immune system simply cannot get it.

Infectionists call such places Peripheral tolerance induction: lessons from immune privileged sites and tissues. "Immunologically privileged regions".

Although at first glance the existence of such sites seems illogical, in fact it is evolutionarily justified. Immune-protected places help us survive. Indeed, if during an infection, the immune system actively attacks, for example, the brain, causing a powerful inflammatory reaction in it, this can lead to serious physiological disorders and even death. Therefore, the body protects the organ in advance from potentially destructive immune defenses.

However, this is just one of the mechanisms that provide viruses and microbes with the opportunity for persistence. There are others. So, the same William Petrie mentions that some viruses can have a latent phase of development. This means that at some period of its existence the virus "sleeps": it does not infect cells, does not multiply. But then it goes into the active phase (reactivated) and begins to vigorously reproduce. This can happen months, years, or even decades after the virus has entered the body.

What viruses and bacteria are capable of persistence

The most famous example of persistence is chickenpox. After the temperature drops and the rash disappears, it seems as if the immune system has completely dealt with the infection. But this is not the case.

The causative agent of chickenpox, the varicella-zoster virus, remains in the nerve cells. Decades later, it can be reactivated by Herpes Simplex Virus Establishment, Maintenance, and Reactivation: In Vitro Modeling of Latency and cause herpes zoster (herpes zoster), a painful disease in which some nerve endings become inflamed. All this is accompanied by a rash similar to chickenpox. In addition to pain, shingles often leads to serious complications of Shingles (Herpes Zoster): lingering neuralgia, eye lesions, paralysis of the cranial and peripheral nerves, inflammation of internal organs - from pneumonia and hepatitis to meningoencephalitis.

Another prime example is the Persistant Viral Infections measles virus. In some people, despite recovery and developed immunity, the virus remains in the cells of the brain. And after 5-15 years it can be reactivated, causing subacute sclerosing panencephalitis. This dangerous disease leads to a sharp deterioration in the mental state, involuntary twitching, muscle stiffness and even coma.

The Epstein-Barr virus (it causes mononucleosis), Persistent Hepatitis C Virus Infection In Vitro: Coevolution of Virus and Host B, C, D, some retroviruses (for example, HIV) and not only have the ability to persist.

Scientists do not exclude Persistent SARS ‑ 2 infections to contribute to long COVID ‑ 19, that the SARS ‑ CoV ‑ 2 coronavirus, which causes COVID ‑ 19, also has the ability to persist.

Perhaps it is the fact that the coronavirus is permanently fixed in the cells of the nervous system and other organs that becomes one of the reasons for the longkovid - the protracted Post Covid Conditions of the consequences of the infection. Some reinfection cases are also possibly due to virus reactivation.

If we talk about bacterial infections Persistent bacterial infections, antibiotic tolerance, and the oxidative stress response, then, for example, tuberculosis, salmonella gastroenteritis, bronchitis, prostatitis, and inflammatory diseases of the pelvic organs can turn into a persistent form.

Why persistence is dangerous

The main risk has already been voiced above. An infection lurking in the body at any time - for example, under the influence of stress, a harsh diet, or other conditions - can be reactivated. And cause an acute illness, sometimes much more serious than when you first met the virus. But this danger is not the only one.

William Petrie Infectionist.

Being infected with a virus that can cause persistent infection means becoming infected for the rest of your life.

A person in whose body a persistent virus or microbe has settled remains a carrier of the disease. And it can transmit the infection to other people without even realizing it.

Is it possible to get rid of persistence

In theory, yes. So, for some persistent viral infections, drugs have been developed that prevent Persistant Viral Infections from leaving the "dormant" (latent) state or multiplying. Some lucky ones are lucky, and they get rid of the infection forever.

An inspiring example is chronic hepatitis C. Several years ago it was considered incurable, that is, it was impossible to cope with the pathogen hidden in the body. But since 2013, pharmaceutical companies have begun to produce drugs, thanks to which at least 90 people out of every 100 infected can say goodbye to chronic hepatitis C. Oral Direct-Acting Agent Therapy for Hepatitis C Virus Infection.

But science has not yet been able to defeat chronic hepatitis B. Medicines help only temporarily suppress the activity of the virus, but not get rid of it at all.

There are serious difficulties in the fight against persistent bacterial infections. Many of them do not respond to antibiotics and do not respond to treatment. Persistent bacterial infections and persister cells.

In general, the best way not to suffer from persistence is to try not to pick up a virus or bacteria capable of it. Therefore, it is important to timely vaccinate against vaccine-controlled infections. And follow the key rules for the prevention of How to Prevent Infections of infectious diseases.

Wash your hands regularly. This is especially important after returning from crowded places, going to the toilet, and before preparing food.
Do not share dishes, cups, personal hygiene items with other people.
Try not to drink raw water from open sources.
Wash fruits and vegetables thoroughly before eating.
Avoid raw or undercooked meats.
Use condoms during sex.