Influenza (Flu): Symptoms and causes.

Influenza, commonly known as the flu, is a highly contagious respiratory illness caused by influenza viruses. It affects the nose, throat, and lungs, leading to a range of mild to severe symptoms.

Overview

Influenza, often shortened to “flu,” is a respiratory illness caused by influenza viruses. These viruses infect the nose, throat, and sometimes the lungs, triggering an immune response that results in a spectrum of symptoms ranging from mild to severe. The flu is highly contagious and spreads readily through respiratory droplets expelled by coughing, sneezing, or talking. It is most prevalent during the winter months in temperate climates. Annual flu epidemics are responsible for significant morbidity and mortality worldwide, necessitating a thorough understanding of the disease for effective prevention and management.

Types of Influenza Viruses

There are three main types of influenza viruses that commonly infect humans:

• Influenza A virus (IAV): This type is highly variable and can cause both seasonal epidemics and pandemics. It has various subtypes based on the surface proteins hemagglutinin (HA) and neuraminidase (NA). For example, H1N1 and H3N2 are subtypes of Influenza A. These viruses can infect both humans and animals, including birds and pigs, and are responsible for pandemics.
• Influenza B virus (IBV): This type is less variable than IAV, they are divided into two lineages: B/Yamagata and B/Victoria primarily infect humans causes seasonal epidemics.
• Influenza C virus (ICV): This type usually causes mild illness and is not associated with epidemics or pandemics. They infect humans and pigs but are less common than A and B types.
• Influenza D viruses: Primarily affect cattle and are not known to infect or cause illness in humans.

Symptoms

Flu symptoms typically come on suddenly and can include:

• Fever or feeling feverish/chills
• Cough (dry or productive)
• Sore throat
• Runny or stuffy nose
• Muscle or body aches
• Headache
• Fatigue (tiredness)
• Some people may experience vomiting and diarrhea, especially children.

The severity and duration of symptoms can vary depending on individual factors like age, overall health, the strain of the virus and immune response. In most cases, symptoms improve within a few days to a week.

Mode of spread

Influenza is caused by infection with influenza viruses. These viruses can spread through the following ways:

• Inhalation: Inhaling respiratory droplets expelled by an infected person coughing, sneezing, or talking.
• Direct contact: Touching an infected person or contaminated surface and then touching your eyes, nose, or mouth.

People with the flu are contagious from about one day before symptoms appear until about 5 to 7 days after they start. Children and people with weakened immune systems may be contagious for a longer period.

Risk Factors

Certain individuals are at higher risk of developing serious complications from influenza, including:

• Young children: Especially those under five years old.
• Adults 65 years and older: Their immune systems may be weakened with age.
• Pregnant women: Changes in the immune system, heart, and lungs during pregnancy make pregnant women more prone to severe illness.
• People with chronic health conditions: Such as asthma, heart disease, diabetes, or chronic lung disease.
• People with weakened immune systems: Due to HIV/AIDS, cancer and on medications like immunosuppressive drugs.
• Healthcare workers: Increased exposure to influenza virus

Diagnosis

Diagnosing influenza can involve:

• Medical history and physical examination: The doctor will inquire about your symptoms, travel history, and potential exposures.

Laboratory testing:

• Rapid influenza diagnostic tests (RIDTs): These point-of-care tests provide a rapid diagnosis but may not always be accurate. These tests can provide results within 15-30 minutes by detecting viral antigens. However, they have variable sensitivity.
• Viral culture: A sample of mucus from the nose or throat is cultured to identify the specific influenza virus.
• Molecular Tests: Such as reverse transcription polymerase chain reaction (RT-PCR), which are more sensitive and specific and can differentiate between influenza A and B.

Treatment

Treatment options for influenza include antiviral medications, supportive care, and prevention through vaccination.

Antiviral Medications

• Oseltamivir (Tamiflu): An oral medication effective against both influenza A and B.
• Zanamivir (Relenza): An inhaled medication also effective against both types.
• Peramivir (Rapivab): An intravenous option for severe cases.
• Baloxavir marboxil (Xofluza): A newer oral antiviral that works by inhibiting viral replication.

These medications are most effective when started within 48 hours of symptom onset.

Supportive Care

• Rest: Helps the body fight the infection.
• Hydration: Important to prevent dehydration.
• Pain Relievers: Medications like acetaminophen or ibuprofen can help reduce fever and alleviate muscle aches and headaches.

Vaccination

The most effective way to prevent the flu is through annual vaccination. Flu vaccines are updated each year to protect against the most current strains of the virus. Vaccination is recommended for everyone aged 6 months and older, especially those at high risk of complications.

Natural Remedies

Several natural remedies may provide symptomatic relief and support the immune system.

• Hydration: Drinking plenty of fluids like water, broth, or herbal teas helps loosen mucus and prevent dehydration.
• Rest: Getting adequate sleep allows the body to focus on recovery.
• Honey: Honey can soothe a sore throat and cough (not recommended for children under 1 year old).
• Garlic: This may possess some antiviral properties, but research is ongoing.
• Zinc lozenges: Zinc may shorten the duration of a cold, but its effectiveness for flu is less clear.
• Vitamin C: While high doses might not prevent the flu, it may slightly reduce symptom duration.
• Elderberry: Early research suggests elderberry extract may shorten flu symptoms.
• Ginger tea: Known for its anti-inflammatory properties, ginger tea can help soothe sore throats and reduce nausea.
• Peppermint tea: Can provide relief from congestion and headaches.
• Chamomile tea: Promotes relaxation and can help with sleep, which is crucial for recovery.

It is important to note that natural remedies should not replace conventional medical treatment, especially for high-risk individuals.

Home Remedies

Home remedies can provide symptomatic relief and support the body’s immune response.

Rest and Hydration:

• Rest: Essential for recovery.
• Fluids: Drinking plenty of fluids like water, herbal teas, and broth helps maintain hydration and alleviate congestion.

Humidifiers:
Using a humidifier can add moisture to the air, which helps ease breathing and soothe irritated nasal passages and throat.

Salt Water Gargle:
Gargling with warm salt water can help soothe a sore throat and reduce swelling.

Warm Compresses

• Applying warm compresses to the forehead and nose can relieve sinus pressure and headaches.
• Steam inhalation: Inhaling steam can help loosen mucus and ease congestion. (Use caution to avoid burns)

Traditional Medicine Systems for Influenza

Some traditional medicine systems offer remedies for influenza, but it’s crucial to consult a qualified practitioner before using them.

Homeopathy

Homeopathy is a complementary therapy based on the principle of “like cures like.” Common homeopathic remedies for the flu include:

• Oscillococcinum: Claimed to reduce the severity and duration of flu symptoms.
• Gelsemium: For flu with fatigue, headache, and muscle aches.
• Bryonia: For flu with dry cough and body aches.

While some people find relief with homeopathy, it is important to note that scientific evidence supporting its effectiveness is limited.

Ayurveda

Ayurveda is an ancient Indian system of medicine that uses natural treatments to promote balance in the body.

• Tulsi (Holy Basil): Known for its antiviral and immune-boosting properties.
• Ginger: Used to reduce inflammation and ease respiratory symptoms.
• Turmeric: Has anti-inflammatory and antioxidant properties.
• Ashwagandha: Helps boost immunity and reduce stress.

Ayurvedic Practices

• Nasya: The practice of administering herbal oils through the nose to clear nasal passages.
• Steam Inhalation: With herbs like eucalyptus or camphor to relieve congestion.

Unani Medicine

Unani medicine is a traditional system of healing based on the teachings of Hippocrates and Galen, incorporating elements of Greco-Arabic medicine.

• Arq e Gulab (Rose Water): Used for its cooling and anti-inflammatory properties.
• Joshanda: A herbal decoction made from a combination of medicinal herbs to treat colds and flu.
• Qarshi Joshanda: A commercially available Unani preparation for flu symptoms.

Alternative Therapies

Various alternative therapies may help support flu recovery and symptom management.

Acupuncture:

Acupuncture involves inserting thin needles into specific points on the body to stimulate healing and relieve symptoms such as headaches, body aches, and congestion.

Aromatherapy

Using essential oils like eucalyptus, peppermint, and tea tree oil can help relieve respiratory symptoms. These oils can be diffused in the air or added to a steam inhalation.

Chiropractic Care

Some people find relief from muscle aches and joint pain associated with the flu through chiropractic adjustments.

It is vital to discuss any alternative therapies with your healthcare provider to ensure safety and avoid interactions with medications.

Management and Prevention

Influenza in Children

Children are particularly susceptible to influenza and its complications. Their symptoms may vary slightly from adults and include:

• Fever
• Cough
• Runny or stuffy nose
• Vomiting and diarrhea (more common than in adults)
• Earache
• Fatigue
• Listlessness

Management of influenza in children

• Monitor their temperature and provide fluids.
• Use over-the-counter medications appropriate for their age (consult a doctor for dosage).
• Ensure adequate rest.
• Consult a doctor if symptoms worsen, fever persists for more than 3 days, or breathing difficulties arise.

Prevention in Children

• Vaccination: Annual flu vaccination is recommended for all children aged 6 months and older.
• Hygiene: Teaching children proper handwashing techniques and encouraging them to cover their mouths when coughing or sneezing can help prevent the spread of the virus.
• Avoiding sick individuals: Keeping children away from people who are ill can reduce their risk of contracting the flu.

Influenza in Teenagers

Teenagers generally experience similar symptoms as adults with influenza. However, they may also experience:

• Extreme fatigue
• Loss of appetite
• Difficulty concentrating

Management of influenza in teenagers:

• Encourage rest and hydration.
• Over-the-counter pain relievers can help manage symptoms.
• Monitor for worsening symptoms and seek medical attention if necessary.

Prevention in teenagers

• Vaccination: Ensuring teens receive their annual flu shot.
• Hygiene: Reinforcing good hygiene practices like frequent handwashing and avoiding close contact with sick individuals.

Influenza in Adults

The typical symptoms of influenza in adults have been described earlier. However, some adults may experience:

• Confusion
• Dizziness
• Worsening of chronic health conditions

Management of influenza in adults:

• Rest and hydration are crucial.
• Over-the-counter pain relievers can help manage symptoms.
• Monitor for worsening symptoms and seek medical attention if necessary.

Prevention in Adults

• Vaccination: Annual flu shots are recommended.
• Healthy Lifestyle: Maintaining a healthy immune system through a balanced diet, regular exercise, and adequate sleep can help prevent infection.

Influenza in Pregnancy

Pregnant women are at higher risk of complications from influenza. Symptoms are similar to those in non-pregnant individuals but may also include:

• Shortness of breath

Management of influenza in pregnancy

• Vaccination is highly recommended before or during pregnancy (consult your doctor).
• Rest and hydration are crucial.
• Over-the-counter pain relievers with doctor approval can help manage symptoms.
• Seek immediate medical attention if symptoms worsen or breathing difficulties arise.

Prevention in Pregnancy

• Vaccination: Pregnant women should receive the inactivated flu vaccine. It is safe during any trimester and can also protect the baby after birth.
• Hygiene: Good hygiene practices are especially important during pregnancy.

Dietary Recommendations for Influenza

While no specific diet can cure influenza, a healthy diet rich in fruits, vegetables, and whole grains can support the immune system during recovery. Here are some additional dietary tips:

• Eat plenty of fruits and vegetables: They provide essential vitamins, minerals, and antioxidants.
• Include whole grains: They offer sustained energy and fiber.
• Consume lean protein sources: They are necessary for building and repairing tissues.
• Stay hydrated: Drink plenty of fluids to prevent dehydration.
• Limit processed foods, sugary drinks, and unhealthy fats: These can hinder immune function.

Foods That Help Fight the Flu

Certain foods can support the immune system and aid in recovery from the flu.

Vitamin C-Rich Foods

• Citrus fruits: Oranges, lemons, and grapefruits.
• Bell peppers: Particularly red bell peppers.
• Kiwifruit: High in vitamin C and antioxidants.

Zinc-Rich Foods

• Meat: Beef, pork, and lamb.
• Shellfish: Oysters and crab.
• Legumes: Chickpeas, lentils, and beans.

Probiotic Foods

• Yogurt: Contains beneficial bacteria that support gut health.
• Kefir: A fermented milk drink rich in probiotics.
• Sauerkraut: Fermented cabbage that provides beneficial probiotics.

Hydrating Foods

• Broth-based soups: Chicken soup is a classic choice that helps with hydration and nutrition.
• Fruits and vegetables with high water content: Such as cucumbers, watermelon, and strawberries.

Prevention guidelines by Centres for Disease Control and Prevention (CDC)

Preventing the flu involves a combination of vaccination, hygiene practices, and lifestyle measures. The most effective way to prevent influenza is annual vaccination. The Centres for Disease Control and Prevention (CDC) recommends yearly flu vaccination for everyone 6 months of age and older. Here are other preventive measures

Vaccination

Annual flu vaccination is the most effective method of prevention. Vaccines are updated yearly to protect against the most prevalent strains.

Hygiene Practices

• Handwashing: Frequent handwashing with soap and water, especially after coughing, sneezing, or touching potentially contaminated surfaces.
• Practice good cough etiquette: Covering the mouth and nose with a tissue or elbow when coughing or sneezing.
• Avoiding Close Contact: Keeping distance from people who are sick and staying home when experiencing flu symptoms.
• Clean and disinfect frequently touched surfaces: This helps reduce the spread of viruses.

Lifestyle Measures

• Healthy Diet: Eating a balanced diet rich in fruits, vegetables, and whole grains to support the immune system.
• Regular Exercise: Maintaining physical activity to promote overall health.
• Adequate Sleep: Ensuring sufficient sleep to help the body recover and maintain a strong immune system.

Complications

Complications from the flu can range from mild to severe and can be life-threatening, particularly in high-risk populations.

Common Complications

• Pneumonia: A serious lung infection that can be caused directly by the influenza virus or by secondary bacterial infection.
• Bronchitis: Inflammation of the airways that can occur after the flu,can cause cough and mucus production
• Sinus and Ear Infections: Inflammation of the sinuses leading to facial pain, congestion, and headache. Ear infections are more common in children.
• Exacerbation of Chronic Conditions: Such as asthma, diabetes, and heart disease.

Severe Complications

• Acute Respiratory Distress Syndrome (ARDS): A severe lung condition requiring intensive care.
• Sepsis: A life-threatening response to infection that can lead to tissue damage and organ failure.
• Myocarditis: Inflammation of the heart muscle.
• Encephalitis: Inflammation of the brain.

When to Seek Emergency Care

Seek immediate medical attention if you experience any of the following symptoms:

• Difficulty breathing or shortness of breath
• Persistent vomiting or inability to keep fluids down
• Confusion, delirium, or altered mental status
• Chest pain or pressure
• Sudden dizziness or severe weakness
• Seizures (especially in children)
• Fever or cough that worsens after initial improvement

Emergency Situations

Certain symptoms indicate the need for immediate medical attention:

In Children

• Fast or labored breathing: Indicative of respiratory distress.
• Bluish skin color: Suggests a lack of oxygen.
• Not drinking enough fluids: Risk of dehydration.
• Severe irritability: Such as not wanting to be held or being inconsolable.
• Flu-like symptoms that improve but then return with fever and worse cough.

In Adults

• Difficulty breathing or shortness of breath.
• Chest or abdominal pain or pressure.
• Sudden dizziness or confusion.
• Severe or persistent vomiting.
• Symptoms that improve but then return with fever and worse cough.

Specialist to Visit

In most cases, a primary care physician or general practitioner can diagnose and manage influenza. However, if complications arise, you may be referred to specialists like:

• Primary Care Physicians: For initial assessment and management.
• Pulmonologist: A doctor specializing in respiratory conditions like pneumonia.
• Cardiologist: A doctor specializing in heart conditions.
• Infectious disease specialist: A doctor with expertise in diagnosing and treating infectious diseases.

Prognosis of Influenza (Outlook)

For most healthy individuals, influenza resolves within a week or two with supportive care or antiviral medications. However, the prognosis can be worse for high-risk populations like pregnant women, young children, and people with chronic health conditions.

Most people recover from the flu within a few days to two weeks, but some can develop complications that require hospitalization and can be life-threatening. The outlook depends on the individual’s overall health, age, and the presence of underlying conditions. Annual vaccination and prompt treatment of symptoms can improve the prognosis.

Conclusion

Influenza is a highly contagious respiratory illness that can range from mild to severe. Vaccination remains the most effective preventive strategy. Early diagnosis, supportive care, and antiviral medications, when appropriate, are crucial for managing influenza and preventing complications. Implementing healthy lifestyle practices like proper hygiene, adequate sleep, and a balanced diet can bolster the immune system and contribute to overall well-being.