Swine Flu: Signs and Symptoms, Causes, Risks, Complications, Diagnosis, Treatment, Prevention and Outlook

Two veterinarians checking swine flu


Swine flu is a disease that usually affects pigs. However, the virus can affect humans too. Most commonly, swine flu of the H1N1 influenza subtype may cause a respiratory disease. It rarely affects humans, but in 2009, an outbreak of swine flu that infected humans, and many died from the infection.

It is important to note, however, that the 2009 outbreak was not completely derived from swine. In fact, it’s a combination of other flu genes from birds, pigs, and humans. During that time, the disease was considered a pandemic but eventually dubbed as a normal flu virus.

The virus had spread to more than 70 countries and led to numerous hospitalizations and even deaths. In the United States alone, 22 million people had contracted H1N1 wherein 98,000 required hospitalizations, and 3,900 people died from H1N1-related causes between April and October that year.

The first cases of the infection were first identified in Mexico in April 2009. It rapidly spread to various countries since it’s a new type of flu virus, and many individuals are susceptible to acquiring it. The infection was self-limiting and many recovered even without the need for hospitalization. Most of the casualties resulted from the vulnerability of many individuals to the infection such as people with underlying diseases, pregnant women, young children, and infants.

By August 10, 2010, the World Health Organization (WHO) has declared the pandemic finally over. Today, with the vaccination available, the illness has become an ordinary flu infection, which is preventable.

2Signs and Symptoms

The various influenza sub type infections have similar signs and symptoms. Usually, the symptoms of flu develop within one to three days, and those infected feel better within a week.   The patients have symptoms of acute respiratory illness, including at least two of the following:

  • Cough
  • Sore throat
  • Fever
  • Body aches
  • Headache
  • Chills
  • Diarrhea and vomiting
  • Joint pains
  • Runny nose
  • Sneezing
  • Loss of appetite
  • Difficulty sleeping


Influenza viruses are named depending on the protein types on the outer layer of the virus – hemagglutinin (H) and neuraminidase (N). In 2009, the H1N1 virus outbreak had spread quickly to more than 70 countries. Though it was popularly known as the swine flu, it’s official term is Novel H1N1 influenza.

The influenza viruses act by infecting the cells of the lining of the nasal cavity, throat and even the lungs. The virus can enter the body when contaminate droplets are inhaled. Moreover, you can acquire the infection when you touch contaminated surface and bring the virus to your nose, mouth or eyes.

Once you contract the virus, the incubation period for the illness is about one to four days. This period is where a person doesn’t feel any symptoms yet. H1N1 is highly contagious on the first day before the symptoms develop to approximately five to seven days after the symptoms emerge.

4Risk factors

People who traveled to a location where many individuals are affected by swine flu are more likely to develop the illness because they have been exposed to the virus. Moreover, those who handle pigs like swine farmers and veterinarians have an increased risk of acquiring the infection.

The swine flu can easily infect people who are more susceptible to infection because of weakened immune systems, including:

  • Infants
  • Children
  • Pregnant women
  • Older adults
  • People with suppressed immune system
  • Those with underlying health issues like asthma, respiratory diseases, and cardiovascular illness


The complications associated with swine flu are usually seen in people with higher medical risks like pregnant women, older adults, those with compromised immune systems, and those with long-term use of medications that can weaken the body’s immune response.

Pneumonia and Bronchitis

Respiratory complications that are associated with swine flu are pneumonia and bronchitis. Bronchitis can be treated accordingly with the right type of antibiotics, as prescribed by the doctor. Pneumonia, meanwhile, is a more serious complication because it may lead to respiratory failure and even death if not treated promptly.

Pregnancy Complications

Any infection during pregnancy is a threat to both the mother and the unborn child. When there is an infection and was not treated immediately, it may lead to various complications such as stillbirth, premature labor, and miscarriage.

Worsening Of Chronic Conditions

Some people who have chronic conditions such as bronchial asthma and heart problem are at a higher risk of suffering complications. Their underlying conditions may worsen because of an ongoing acute infection in the body.

Deterioration Of Current Health Conditions

Individuals who are undergoing long-term medical supervision and treatment for their illness are at a heightened risk when they contract the swine flu. The virus may worsen their current health conditions. Those on long-term steroid medications are at a higher risk of suffering from complications related to the H1N1 flu because of a weakened immune system.

People with cancer, diabetes, and other chronic diseases may suffer from the robust and potentially-fatal complications of the H1N1 flu.

Other Complications

The other complications of swine flu include encephalitis (inflammation of the brain), febrile seizures or convulsions, meningitis (infection of the covering of the spinal cord and brain), otitis media (infection of the ears), tonsillitis (inflammation of the tonsils) and sinusitis (inflammation of the sinuses).


The Centers for Disease Control and Prevention (CDC) released a guideline on how the swine flu should be diagnosed. The H1N1 flu is diagnosed if there is:

  • Acute fever with inflamed airways within one week of close contact with someone who has been diagnosed with H1N1 influenza An infection.
  • Acute fever with inflamed airways within one week of travel to a location or community with one or more confirmed cases of the infection.
  • Acute fever with inflamed and infected airways in a person living in a community where there is one confirmed case of H1N1 influenza An infection.


Viral infections are self-limiting. This means that there is usually no cure for them and they go away on their own. The only treatment given is to provide relief for all the symptoms present. In fact, all the medicines given are for symptoms relief like:

  • Bed rest
  • Increased fluid intake
  • For a sore throat, gargling with saline water solution is recommended
  • Medicines as prescribed by the doctor such as cough suppressants, decongestants, antipyretics, antihistamines and analgesics
  • Medicines should be prescribed by a doctor, don’t self-medicate because you might end up overdosing. Moreover, do not take decongestants if you have high blood pressure.

However, generally, the doctor can give antivirals like zanamivir (Relenza) and oseltamivir (Tamiflu). These drugs can help reduce the severity of the symptoms and certain complications.

However, since viruses can easily form resistance to these medicines, they are not prescribed immediately. In fact, they are only prescribed to individuals to people who are at a higher risk of developing complications such as pregnant women, older adults, children and those with weakened immune systems.


When the first case of swine flu in humans emerged, there was still no means to prevent its development. Today, there are now vaccines against the specific swine flu strain to help prevent its outbreak again.

Talk with your physician about getting these vaccines for your family. Moreover, there are other ways to prevent getting this illness and preventing others from getting it from you.

  • Stay at home when you’re sick. It’s important to just rest for your body to recover and at the same time, reduce the risk of other people getting the virus from you.
  • Practice proper hand washing to reduce the risk of cross contamination.
  • Contain your cough and sneezes by covering your mouth and nose with a tissue.
  • Stay away from crowds when there is an ongoing outbreak of swine flu or if it’s the flu season.
  • Don’t touch surfaces and then touch your eyes, nose, and mouth, viruses can stay on some surfaces for a couple of hours.
  • Staying healthy by eating a balanced diet, exercising regularly, getting adequate sleep and choosing healthier food options like fruits and vegetables.
  • Get your influenza vaccine from your doctor.


Viral infections are self-limiting, which means that they go away on their own without the need for treatment. However, as said earlier, when the group of individuals affected is high-risk, they may suffer from health consequences, including death.

The 2009 influenza pandemic has affected many lives and the death rates among pregnant women were alarming. There were many deaths and most of them are from the high-risk groups. They have weakened immune systems which cannot fight the viral infection. As a result, they could suffer from serious consequences.

Moreover, people with underlying health conditions like heart problems and respiratory diseases could suffer serious complications, which could lead to the death of the patient. Simple measures like covering the nose and mouth when sneezing, staying away from big crowds and having the influenza vaccine could help reduce these severe complications.

When you have the signs and symptoms stated earlier, you should seek medical attention from a physician. This way, you can undergo the needed examinations to determine if you really have swine flu.