Viral infection is an infectious disease caused by a virus. This infection is usually passed from person to person. However, viral infections can also be transmitted through animal bites or objects contaminated with the virus.
Viruses are microorganisms that are smaller than bacteria. These microorganisms only consist of a core of genetic material, namely DNA and RNA, as well as a protective layer in the form of protein.
Unlike bacteria, viruses are parasitic and cannot live without a host, such as humans, animals or plants. Viruses that attack the host cell will reproduce and kill the host cell.
Viruses can attack various tissues or organs in the body, such as the respiratory or digestive tract. However, not all viruses that enter the body can cause disease. This happens because the body's immune system is working properly to fight the incoming virus.
Causes of Viral Infections
Viral infection occurs when a virus enters a person's body. After entering the body, the virus then attacks healthy body cells, and multiplies rapidly and kills these body cells.
There are many viruses that cause infection. For example, the type of virus that infects the respiratory tract is different from the type of virus that infects the digestive tract.
The following are types of viral infections based on the organs affected and how they are spread:
Viral infection of the respiratory tract
This viral infection attacks the upper or lower respiratory system. Viral infections of the respiratory system can affect several organs, such as the nose, sinuses, throat, and lungs.
In general, this viral infection is transmitted when splashes of saliva from coughs or sneezes of infected sufferers are inhaled by other people. Transmission can also occur if someone touches the nose or mouth without washing their hands first after touching a contaminated object.
The following are some diseases of the respiratory tract due to viral infections:
- Flu , which is caused by the Influenza virus
- Bronchiolitis, which can be caused by Respiratory syncytial virus (RSV), Adenovirus , or Rhinovirus
- COVID-19 , which is caused by the Coronavirus
- Croup, which is caused by the Parainfluenza virus
Viral infection of the digestive tract
Viral infections of the digestive tract affect organs in the digestive system, such as the stomach and intestines. This type of virus spreads through food or water contaminated with the patient's feces or faeces.
In addition, touching your mouth or eating without washing your hands thoroughly after defecating can also cause transmission.
One example of a viral infection in the digestive tract is gastroenteritis . This disease can be caused by various types of viruses, namely Norovirus , Rotavirus , Astrovirus , and Adenovirus .
Viral infection of the skin
Viral infections that attack the skin can cause rashes, sores, or bumps on the skin. Generally, viruses that infect the skin are spread through saliva splashes or sneezes from someone who is infected.
In addition, transmission can also occur through contact with fluids on the injured skin. Insect bites, such as mosquitoes, can also spread viruses that infect the skin.
Some examples of viral infections of the skin and the viruses that cause them are:
- Chickenpox , which is caused by the Varicella zoster virus
- Measles, which is caused by the Paramyxovirus group of viruses
- Molluscum contagiosum , which is caused by the Molluscum contagiosum virus
- Chikungunya, which is caused by the Alphavirus group of viruses and is transmitted through the bite of the Aedes aegypti mosquito
Viral infection of the liver
Viral infection of the liver is a common cause of hepatitis . Depending on the type of virus, this virus can be spread through food contaminated with the faeces (feces) of an infected person.
Transmission can also occur through the use of unsterile needles, as well as direct contact with blood, urine, sperm or vaginal fluids of an infected person. Examples of liver disease caused by viral infections are hepatitis A, B, C, D, and E.
Viral infection of the nervous system
The central nervous system which consists of the brain and spinal cord can also be infected with the virus. Several types of viruses that infect the central nervous system are herpes simplex type 2 (HSV-2), varicella-zoster, enterovirus, arbovirus, and poliovirus .
Viruses that infect the nervous system can be transmitted in various ways and trigger a number of diseases. For example, enteroviruses are spread by droplets when an infected person sneezes or coughs. Meanwhile , arboviruses are transmitted through insect bites, such as mosquitoes or ticks.
Some diseases caused by viral infections of the nervous system are:
In rabies, the virus can be transmitted through the bite of an animal infected with the rabies virus, both wild and domestic animals. Several types of animals that can transmit rabies infection are cats, dogs, bats, cows, and goats.
Viral infection of the genitals
Viral infections of the genitals are transmitted through sexual intercourse, which often changes partners and does not use condoms . This type of virus causes rashes and bumps on the genitals.
Some diseases caused by viral infections of the genitals are:
- Genital warts , caused by the human papillomavirus (HPV
- Genital herpes , caused by the Herpes simplex virus (HSV)
Viral infection of blood vessels
In addition to the number of viral infections described above, there is also a viral infection called viral hemorrhagic fever (VHF). This type of viral infection causes blood clotting disorders and damage to the walls of blood vessels, thus triggering bleeding.
This viral infection can be transmitted through insect bites, such as mosquitoes, as well as direct contact with the blood or body fluids of an infected person. Some examples of diseases that are classified as VHF are:
- Dengue fever
- Yellow fever
- Lassa Fever
- Marburg fever
Viral infection of the immune system
Viruses can also infect the immune system, one of which is the human immunodeficiency virus (HIV).
HIV is a virus that damages the immune system, which if not treated immediately can develop into AIDS. AIDS ( acquired immune deficiency syndrome ) is the final stage of HIV which weakens the immune system.
HIV/AIDS is a viral infection that can be transmitted through sex, sharing needles and blood transfusions. This virus can spread from pregnant women to the fetus they contain, or to the baby through childbirth and breastfeeding.
Risk factors for viral infection
Viral infections can happen to anyone. However, there are several factors that can increase a person's risk of getting a viral infection, namely:
- Elderly (elderly) or children
- Have a weak immune system due to disorders of the immune system, such as HIV / AIDS, kidney disease , and cancer treatment
- Have a history of chronic diseases, such as asthma, diabetes, tuberculosis , and heart disease
- Suffering from malnutrition or malnutrition
- Experiencing stress
- Not getting enough rest
- Sharing needles
- Having sex without using a condom
- Multiple sexual partners
Symptoms of Viral Infection
Symptoms of a viral infection vary widely, depending on the organs affected. Some of the symptoms are:
- Have a cold
- Muscle and joint pain
- stomach cramps
- Nausea and vomiting
- Loss of appetite
- Weight loss
- Lumps on the surface of the skin
- skin rash
- Genital rash
- Pain when urinating
- Dark urine
When to see a doctor
Immediately to the doctor if the body temperature rises to 39 o C and above. Also pay attention to the symptoms that can accompany a fever and require immediate medical attention, such as:
- Severe headache
- Hard to breathe
- Pain in the chest and stomach
- Constant vomiting
- Weight loss drastically
- Stiff neck or pain when looking down
- Confusion or loss of consciousness
Diagnosing Viral Infections
To diagnose a viral infection, the doctor will ask questions and answers about the patient's symptoms and medical history. After that, the doctor will carry out a thorough physical examination.
In some cases, doctors need to carry out several further tests to establish a diagnosis. Some of these checks are:
- Complete blood count , to determine the number of white blood cells
- C -reactive protein (CRP) test, to measure levels of reactive C protein produced in the liver
- Enzyme-liked immunosorbent assay (ELISA), to detect antibodies in the blood associated with viral infections, such as Varicella zoster virus, HIV virus, and hepatitis B and C viruses
- Polymerase chain reaction ( PCR ), to detect viruses in the body
- Scanning with an electron microscope, to examine blood samples or patient tissue
Please note, viral infections are sometimes difficult to distinguish from bacterial infections. To be sure, the doctor can do a culture, namely taking a sample of the patient's blood or urine to be examined in the laboratory.
Doctors can also run a biopsy , which is taking samples of infected body tissue for examination under a microscope.
Viral Infection Treatment
Treatment of viral infections depends on the type the patient has. Some viral infections, such as viral infections of the respiratory and digestive systems, generally don't need to be treated because the symptoms will go away on their own.
However, doctors can prescribe several types of drugs whose types will be adjusted to the symptoms of the patient, such as:
- Antiemetic, to treat nausea and vomiting
- Decongestants , to treat colds or nasal congestion
- Loperamide, to treat diarrhea
- Paracetamol and non-steroidal anti-inflammatory drugs (NSAIDs), to reduce fever and reduce pain
In cases of viral infections such as flu, herpes, and HIV, doctors can prescribe antiviral drugs , such as oseltamivir, acyclovir , valacyclovir, and nevirapine.
Interferon can also be given to treat chronic hepatitis B and C, as well as genital warts. Note, however, that antiviral drugs, including interferons , only prevent the virus from multiplying and do not kill the virus itself.
Apart from that, the patient will also be advised to get plenty of rest and drink water. If necessary, the doctor will provide fluid intake through an IV.
Viral Infection Complications
In some cases, the immune system is unable to fight viruses that infect the body. This condition can cause serious complications, such as:
- Cervical cancer, due to infection with the HPV virus
- Opportunistic infections , due to infection with the HIV virus
- Acute bronchitis, caused by a viral infection of the upper respiratory tract, such as rhinovirus
- Cirrhosis, due to infection with hepatitis B, C, and D viruses
- Otitis media (middle ear infection), due to viral infections of the respiratory tract, such as influenza
- Fetal defects, due to infection with the HSV virus, cytomegalovirus , or rubella in pregnant women
- Secondary bacterial infection
Virus Infection Prevention
Some viral infections can be prevented by administering vaccines , which aim to stimulate a person's immune system. The vaccine is given by injection at a certain age before someone is infected with the virus.
A number of viruses that can be prevented by administering vaccines, namely:
- Yellow fever
- Hepatitis A
- Hepatitis B
- Human papillomavirus (HPV)
- Japanese encephalitis
Doctors can also give immunoglobulin, which is part of the blood plasma that contains antibodies, to fight disease. Administration of immunoglobulin is useful for patients who experience immune disorders.
Viral infections that can be prevented by administering immunoglobulin include HIV, hepatitis A, hepatitis B, hepatitis C, influenza, rabies, and Varicella zoster infection .
Other efforts to prevent viral infections are:
- Always wash your hands with water and soap before or after activities
- Do not eat food that has not been cooked thoroughly
- Avoid contact with infected people and objects contaminated with the virus
- Avoid insect bites, such as mosquitoes
- Cover mouth and nose with hand or tissue when coughing or sneezing
- Practice safe sex, for example by wearing a condom and being faithful to one partner
- Undergo a TORCH examination before planning a pregnancy
- Undergo regular pap smears for women
- Provide routine vaccinations for pets
- Wear a mask when you are sick or when caring for a sick person