Treatment of viral infections
Treatment of viral infections involves managing diseases caused by viruses, which are microscopic organisms requiring a living host to replicate. Common viral infections include those caused by herpesviruses, influenza viruses, and hepatitis viruses. While some viral infections, like the common cold, resolve on their own, others, such as HIV, require antiviral medications to prevent severe health consequences. Antiviral therapies aim to disrupt the virus's replication cycle and may include drugs like acyclovir for herpesvirus infections or oseltamivir for influenza.
Vaccination plays a crucial role in preventing viral infections, particularly for diseases like hepatitis A and influenza. Hepatitis B and C require various treatments, including interferons and antiviral medications, depending on the infection's chronicity. The severity of viral infections can range from mild symptoms to life-threatening conditions, highlighting the importance of ongoing research in virology and public health. As viral infections affect millions worldwide, effective treatment and preventive measures remain essential for global health management.
Treatment of viral infections
Definition
Treatment for viral infections involves therapy to manage infections caused by a virus, an intracellular parasitic microorganism that is smaller than bacteria. Some common viral infections that affect humans worldwide are infectious caused by herpesvirus, influenza virus, and hepatitis virus.
Viral Infections
The goal of a virus is to replicate itself. To do so, a virus must invade a living cell and use that cell’s chemical mechanisms to replicate. The existence of a virus is dependent on the metabolic functioning of the host cell it attacks.
Some viral infections are self-limiting and will run their course without treatment. An example of this is the common cold, which has a seven- to ten-day course of illness. However, other viruses cause illness with severe symptoms and require pharmacological treatment. An example of a viral infection that requires treatment is human immunodeficiency virus (HIV) infection. Without pharmacological treatment, HIV can lead to acquired immunodeficiency syndrome (AIDS). In general, antiviral medications are designed to interfere with the functioning of a virus or with its ability to replicate. Antiviral drugs may interact with the enzymes or proteins in the virus to break the viral replication cycle. The use of vaccines, when available, is one way to treat viral infections through prevention.
Herpesvirus. Herpes simplex viruses (HSV) belong to the family of DNA (deoxyribonucleic acid) viruses that cause blisters on a person’s skin, mucous membranes, or genitals. This family of viruses includes HSV-1, HSV-2, cytomegalovirus, varicella zoster virus (chickenpox and shingles), Epstein-Barr virus, and herpesvirus type-6.
The pharmacologic treatment for herpesviruses is aimed at relieving the acute symptoms and preventing recurrences. No cure exists for herpesviruses, but medications can be employed to treat and lessen the severity of these diseases. Drug therapy can also increase the time the virus is in its latent state and can minimize symptoms.
Drug therapy for HSV-1 and HSV-2 requires five to ten days of oral antiviral medications. The most common antivirals for these infections are acyclovir (Zovirax), famciclovir (Famivir), and valacycloir (Valtrex). If blisters are present, topical medications may be used. In severely immunosuppressed persons, antiviral drugs can be given intravenously. Ocular herpes is treated with latanoprost, an antiglaucoma medication, to avoid corneal blindness. Ocular herpes can also be managed with medicated ophthalmic drops. Although recurrences may happen, antiviral prophylaxis medications are rarely used because of their high cost.
Influenza. The influenza virus, or flu, is labeled as A, B, or C type. The treatment of influenza depends on the type of flu a person contracts. The best treatment for influenza is to prevent infection through annual vaccination. The treatment for influenza once it is acquired is limited. Amantadine (Symmetrel) is the drug of choice; it has been available since 1966. Neuraminidase inhibitors treat active viral diseases. Oseltamivir (Tamiflu) and zanamivir (Relenza) can be given by mouth to shorten the course of the illness from seven to five days. Antivirals are ineffective in the treatment of the common cold.
Hepatitis. Hepatitis, or inflammation of the liver, can occur with alcoholism, drug use, autoimmune disease, metabolic disease, and diverse infections. Hepatitis, caused by numerous viruses, can be an acute infection or a chronic one. Sometimes, persons with hepatitis are asymptomatic.
Hepatitis A is spread mostly through contaminated food or tap water and will usually resolve with no treatment within a few weeks. The best treatment for hepatitis A is prevention with vaccines.
Hepatitis B is contracted through infected blood, sexual activity with an infected person, or childbirth. Acute hepatitis B usually resolves without treatment, but if treatment is needed, the drug lamivudine is available. Chronic hepatitis B can be treated with alpha interferon, lamivudine, peginterferon, or adefovir dipivoxil.
Hepatitis C is spread most often by contaminated blood. The drug of choice for treating chronic hepatitis C is peginterferon, sometimes in combination with ribavirin. Hepatitis D comes from infected blood and is treated with alpha interferon. Hepatitis E, uncommon in the United States, is contracted from contaminated food and water. Treatment is usually not needed because it will resolve on its own.
Impact
Viral infections can be minor and come with few symptoms, or they can be severe and life-threatening. Global viral infections include relatively minor diseases such as the common cold, influenza, and chickenpox, but also serious diseases such as Ebola, AIDS, severe acute respiratory syndrome (SARS), and avian influenza. Other diseases are under investigation as viral and include multiple sclerosis and chronic fatigue syndrome. Virology, the study of viruses, is a critical component of modern biology and genetics.
According to the Centers for Disease Control and Prevention (CDC), from 2010 to 2024, 9.3 million to 41 million people contracted the flu each year, which caused 6,300 to 52,000 deaths. In the past, the number of deaths has been much higher. In 1919, a worldwide flu epidemic resulted in about 20 million deaths. One in five Americans, or about 846 million people between the ages of 15 and 49, is infected with genital herpes, according to the World Health Organization (WHO) in 2024. Neonatal herpes has a 50 percent mortality rate. Because of a pediatric vaccine, cases of viral hepatitis A in the United States have declined about 97 percent, with 44,650 cases and 415 deaths, according to a 2022 Morbidity and Mortality Weekly Report. Persons living with chronic viral hepatitis B numbered up to 254 million in 2022, while the number of those living with chronic infection of viral hepatitis C was 50 million persons, according to the CDC in 2024. Influenza in a pregnant woman can damage a fetus and can kill an adult. Treating viral disease remains a key goal of global population health.
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