Upon entry into the body, viruses penetrate host cells, hijacking their internal mechanisms for replication and dissemination. This process often damages the host cells and prompts the immune system to mount a response.
The Most Common Viral Infections
Viruses represent a diverse group of infectious agents responsible for various diseases. For instance, the common cold, characterized by viral inflammation of the throat and paranasal sinuses, can be attributed to over 200 virus types. These viral infections are most commonly transmitted through direct contact with an infected individual, droplets, and upper respiratory tract infections. Cold symptoms typically manifest during decreased immune function, such as in spring and autumn.
Other Ones
Other viral diseases include:
- Flu
- Herpes labialis, mouth, throat, genitals, conjunctiva, cornea, and skin
- Viral diseases of childhood – measles, rubella, mumps (common parotitis), and chickenpox
- Shingles
- Infectious mononucleosis
- Cytomegaly
- Erythema infectiosum
- Viral hepatitis (most often type B and C)
- HIV infection
- Tick-borne encephalitis
- Rabies
- Condyloma acuminata
Symptoms
Viral infections, such as rhinopharyngitis, commonly known as the common cold, are prevalent. Various pathogens, including rhinoviruses and adenoviruses cause them. On average, adults experience 2 to 4 cold episodes annually. Furthermore, there are other viral infections, such as acute influenza, caused by RNA viruses. These infections can affect the throat, larynx, tonsils, paranasal sinuses, and middle ear, leading to inflammation.
The course of the viral infection, i.e., the symptoms occurring at that time, depends on the specific disease. For example, typical symptoms of a cold include:
- Sub febrile condition (up to 38 degrees), less frequent fever
- Sore throat
- Runny nose
- Moderate cough (often wet)
- Pain in the paranasal sinuses, less often in the head and muscles
When it comes to the flu, you may experience:
- Fever above 39 degrees Celsius
- Chills and muscle pain
- Severe headache
- Dry tiring cough
- Shortness of breath
- Chest pain
Less common manifestations of the flu include a severe sore throat and a runny nose. Nevertheless, diarrhea is possible with this viral infection, particularly in little kids. In addition to fever, it is one of the reasons for severe dehydration of the organism, which can happen during the infection. Please remember that signs develop and can change at various phases of infection. For example, a dry cough frequently turns into a wet one used to expectorate the collected secretions.
When Does Infection Occur?
Each infection develops at a specific pace and proceeds in several steps. The first signs of an upcoming disease are usually general body weakness, lack of energy, drowsiness, and fatigue. At this time, the virus is just hatching in the human body.
In the first phase of viral infection, i.e., the vascular phase, we observe several symptoms: sore throat, fever, cough, and rhinitis. Further development of the infection leads to further symptoms, such as headache or muscle and osteoarticular pain.
The viral infection usually lasts 5-7 days. The duration of the disease may vary depending on many factors:
- The type of virus that caused it
- A person’s overall health (immunity level)
- The person’s age
- The treatment method is undertaken
It is worth knowing that bacterial superinfection may also occur in the case of a viral infection, leading to a more severe disease. Such situations are rare, but the course of the condition cannot be ruled out. The weakened body then has no strength to defend itself against further pathogens, and its natural protective barrier is violated, which makes it easier for harmful factors to enter the body.
Viral And Bacterial Infection
The question often arises among patients: Is influenza caused by a viral or bacterial infection? The clarification has been provided earlier. In both cases, viruses are the source of infection; influenza is not attributed to bacteria.
It is imperative to delineate the disparities between viral and bacterial infections. Viruses are infectious entities at the interface of the living and non-living realms. Lacking a cellular framework, they replicate by utilizing the host’s cells in living organisms, including humans, various animals, plants, fungi, and even bacteria.
It is worth noting that some infections may be caused by both viral and bacterial. This is the case with pharyngitis and tonsillitis, also known as angina. How can you distinguish a viral infection from a bacterial infection? In this case, the former manifests with a fever of up to 39 degrees, severe sore throat, and mucosal congestion.
For comparison, bacterial (streptococcal) angina manifests with a fever exceeding 39 or even 40 degrees, chills, intense sore throat, muscle pain, enlarged lymph nodes, and a characteristic white coating on the tonsils.
As for other comparisons, streptococcal strep throat is much more severe than a viral cold, and compared to the flu, it is distinguished by severe sore throat. Bacterial pneumonia is characterized by a very high fever (above 40 degrees) and a strong, wet cough.
Differences in laboratory test results may also be indicated. While leukopenia and lymphocytosis occur in viral infections, leukocytosis, i.e., an increased number of white blood cells, is typical of viral infections.
Viral Infection In A Child
The incidence of viral infections in children surpasses that in adults, with children experiencing up to 8-9 colds and frequent flu episodes annually. Factors contributing to this trend include the relatively low effectiveness of the immune system, particularly after six months from birth, and the consequent reliance on maternal antibodies until the child develops independent immunity in preschool and school age.
The manifestations of viral infections in infants are typically characterized by fever, cough, and apnea. At the same time, young children commonly exhibit symptoms such as nausea, vomiting, and diarrhea, especially in cases of flu.
In managing viral infections in children, priority should be given to administering age-appropriate fever-reducing and pain-relieving medications, cough remedies, and vasoconstrictors for rhinitis.
Regarding the return of children to kindergarten post-infection, while no strict guidelines exist, the child must be devoid of fever or low-grade fever and any other acute symptoms. It’s essential to remember that children can remain infectious for up to 10 days from the onset of the infection.
Viral Infection During Pregnancy
For pregnant women, it is important to protect against viral infections. A viral infection is a contagious condition. However, the good news is most viruses will not harm the fetus. Nevertheless, some of them may provoke miscarriage or birth defects.
The flu and the common cold are examples of viral infections. Other examples are:
- Chickenpox
- Cytomegalovirus
- Rubella
- Zika virus
- COVID-19
Pregnant women can get exposed to viral infections by other people. That is because they spread straight through touching, kissing, or sexual activity. They may also get them indirectly, e.g., through coughing or sneezing and contact with infected surfaces, food, and water. Being exposed does not mean the individual will become sick.
Symptoms
You should pay close attention to the thermometer readings. A temperature above 38 degrees may be dangerous for the fetus in this phase of pregnancy, so after consulting a doctor, it should be reduced with antipyretic drugs approved for use in this particular period of life. You should also see a doctor if the infection does not subside after 3 days and even more so if the symptoms worsen.
Diagnosis
A specialist may often diagnose viral infection by listening to patients’ symptoms and examining them.
They might use imaging tests if they believe the patient has a viral infection causing severe inflammation in internal organs. We usually talk about X-rays, ultrasound, MRI, or CT imaging. Those methods will not diagnose a viral infection but can help specialists understand how it influences the organism.
Tests
The doctor may collect and send body fluid or tissue samples to a laboratory where the specialists will look for indications of a viral infection. Types of samples they might take include:
- Blood
- Saliva
- Phlegm or mucus
- Cells from the nose or nasopharynx
- Skin or other affected tissue
- Fluid around the brain and spinal cord
- Urine
- Stool
- Cells from the cervix
Treatment
During treatment, it is essential to address inflammation symptoms in the body, including fever, sore throat, headache, muscle and joint pain, and sinus discomfort.
Secondly, it is worth supporting the immune system in the fight against pathogens. The ideal solution is dual-track measures. In this context, specialists can recommend an over-the-counter drug for viral infections containing ingredients such as:
- Salicylamide – a non-steroidal anti-inflammatory drug that relieves pain and fever
- Vitamin C and rutoside – stimulate the immune system to fight viruses even more effectively
Please remember that antibiotics for viral infections are ineffective and inadvisable. These types of drugs only work on bacteria.
If the patient does not have a high fever, it is worth basking in a warm bed (however, you should not overheat in the case of high temperature). You should also drink plenty of water and air your apartment regularly.
Complications
Complications following a viral infection may persist for several days or even weeks. Typical and harmless consequences are:
- Weakness
- Cough
- Runny nose
A bigger problem is bacterial superinfections, such as sinus infections and subsequent, more severe infections, especially after the flu.
Immunity
The immune system defends the organism against infections. It makes proteins named antibodies that counteract or kill microorganisms like viruses and bacteria. You get protection from a distinguishing condition when the immune system produces an antibody.
Function
When your immune system works correctly, it differences between cells that are yours and those that do not belong in the organism. Then it activates and mobilizes to kill microorganisms that may harm you.
The response depends on the virus type and where it enters the organism. The immune system can identify the intruder (thanks to the virus’s protein coat) and initiate suitable immunological processes.
The humoral answer involves the production of antibodies characteristic of a given virus that neutralizes its destructive existence. In turn, the cellular response is associated with the infected cells’ recognition and the activation of cytotoxic mechanisms against them, aimed at their destruction to stop the virus from multiplying and spreading throughout the organism.
After eliminating the virus from the body, the immune system maintains the so-called immunological memory, i.e., protection against repeated infection with the same virus in the future.
But this process doesn’t always go this smoothly. Sometimes, the immune system doesn’t function correctly. For example, it may be too weak to fight with the invading microorganisms or establish too powerful of a reaction.
Prevention
Prevention plays a fundamental role in preventing viral infections.
Pharmacological prevention also plays an essential role in the case of people with reduced immunity (children, seniors, chronically ill people, and taking certain medications). It involves, among others, supporting the immune system. Get vaccinated. There are vaccines for numerous bacterial infections.
Diet
Immunity can also be supported by following specific dietary recommendations. A diet that strengthens the immune system should include products such as:
- Fish and seafood, which are a rich source of well-composed polyunsaturated fatty acids omega 3 and omega 6
- Fruits and vegetables are a source of vitamins and minerals, including, above all, vitamin C, as well as D3, B6, or K
- Pickled cucumbers and cabbage, sour milk, kefir, natural yogurt, buttermilk – considered the best natural prebiotics
- Garlic, onion, leek, and chives contain huge amounts of vitamins and minerals, as well as phytoncides (such as allicin) with bactericidal and fungicidal properties (hence the name natural antibiotics)
Sources
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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7122971/ - Infections. NIH.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7152149/ - Understanding Viral Infection Mechanisms and Patient Symptoms for the Development of COVID-19 Therapeutics. NIH.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7915126/ - Overview: Common colds. NIH.
https://www.ncbi.nlm.nih.gov/books/NBK279543/ - Influenza. NIH.
https://www.ncbi.nlm.nih.gov/books/NBK459363/ - Bacterial Infections: Overview. NIH.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7149789/ - Common childhood viral infections. NIH.
https://pubmed.ncbi.nlm.nih.gov/25703483/ - Viral Infections During Pregnancy: The Big Challenge Threatening Maternal and Fetal Health. NIH.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8843053/ - Diagnosis of Viral Infections. NIH.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7120824/ - Trends and strategies to combat viral infections: A review on FDA approved antiviral drugs. NIH.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8055758/ - The immune system. NIH.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5091071/ - Viral Infections, an Overview with a Focus on Prevention of Transmission. NIH.
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