Difference between SARS and H1N1

Respiratory tract infections form a considerable threat worldwide, causing significantly large numbers of deaths. While both SARS and the H1N1 virus cause respiratory illnesses, they differ with regards to a variety of properties. In recent times, emerging pathogens like the influenza A virus and coronavirus have resulted in a range of outbreaks worldwide and while both forms of the virus are responsible for such infections, each form of the virus is known to exhibit different mechanisms of replication as well as different virulence factors and incubation periods. SARS is a coronavirus belonging to a large family of coronaviruses known to cause a range of illnesses in humans ranging from the common cold to MERS [7]. H1N1 on the other hand is known to infect many people just by casual contact like sitting next to an infected person. Regardless of the differences, individuals should take the appropriate precautions to prevent the spread of these viruses.

What is SARS and what is H1N1?

A coronavirus is a common form of virus that is known to typically cause upper respiratory tract illnesses. There are six different kinds of coronaviruses that are known to infect humans. Four of these viral forms are known to cause common infections with most people experiencing at least one of them at some point in their lifetime [2]. The two remaining forms of coronavirus are less common but are more deadly and are known to cause SARS and Middle East Respiratory Syndrome (MERS). Severe Acute Respiratory Syndrome (commonly known as SARS) is a viral respiratory illness caused by a family of coronaviruses that was first identified in Asia in 2003 [1] while H1N1 (also known as swine influenza) is a respiratory disease caused by the influenza virus. It is known to infect the respiratory tract of pigs resulting in nasal secretions as well as other flu-like symptoms that are common in animals [5].

Causes of SARS and H1N1

SARS is caused by a member of the coronavirus family of viruses known to affect the respiratory system while H1N1on the other hand is thought to have originated in pigs. Before the first appearance of SARS, coronaviruses were not particularly dangerous to humans although they had been known to cause severe diseases in animals [3]. SARS was first identified in 2003 and it was thought to be an animal virus originating from an animal reservoir such as bats before spreading to other animals such as civet cats and subsequently to humans within the Guangdong province of southern China [1] while H1N1 was first discovered in humans somewhere in 2009 as a result of a pandemic affecting people throughout the world on multiple continents.

How is SARS and H1N1 spread?

H1N1 is caused by a strain of the influenza virus known to only infect pigs however this virus may mutate, making them more easily transmissible among humans. The disease is known to last for about three to seven days with more serious infections lasting longer for a period of about nine to ten days. Swine flu is very contagious with the disease being spread through saliva and mucus particles. Common methods for spreading include sneezing, coughing and coming into contact with a germ-covered surface.

Transmission of SARS on the other hand is via close person-to-person contact either by kissing, hugging, sharing of food and drinking utensils as well as talking to someone close by such that aerosol droplets can be ingested [6]. Transmission will most likely occur between individuals who have lived or cared for someone with the disease or who has had direct contact with respiratory secretions or bodily fluids of a patient [4]. Transmission is thought to occur most readily by respiratory droplets that are produced when an infected person coughs or sneezes and which are propelled a short distance through the air, eventually being deposited on the mucous membranes of the mouth, nose, eyes and individuals nearby [2]. The virus can also spread when a person touches a surface or object that is contaminated with infectious droplets and then proceeds to touch their mouth, nose or eyes. Commonly contaminated surfaces include door handles, doorbells and telephones which are often touched by many people.

The spreading of SARS usually occurs during the second week of infection as it is during this period that virus excretion in respiratory secretions and stool tend to peak while H1N1 is contagious for about one day before symptoms develop to about five to seven days after symptoms develop [5]. Compared to H1N1, SARS does not spread as easily from person to person with many documented cases stating that contraction occurred as a result of coming into contact with an infected individual.

Symptoms of SARS and H1N1

Symptoms of SARS usually occur from about 2 to 10 days after individuals have come into contact with the virus while symptoms of H1N1 usually occur from about 3 to 10 days after infection. After infection with SARS, symptoms tend to begin with a high fever and an overall feeling of discomfort and body aches [4]. Approximately 10 to 20 % of patient’s exhibit diarrhoea and after 2 to 7 days they may develop a dry cough. People with active symptoms are known to be contagious however it is not known for how long a person may be contagious for, before and after those symptoms appear. Less common symptoms include diarrhoea, dizziness, nausea, vomiting, runny noses and sore throats however, to date, no specific symptom or group of symptoms have been proven to be specific for the diagnosis of SARS [2].  Coughing, shortness of breath and diarrhoea are commonly present in the first and second week of illness however severe cases of infection may lead to respiratory distress. Most patients also develop pneumonia. More serious complications that may arise as a result of SARS infection include respiratory failure as well as liver and heart failure. These complications are more likely to occur in people aged over 60 years and for those with pre-existing problems like diabetes and hepatitis. Symptoms of H1N1 while similar to SARS are much milder and include chills, fever, coughing, sore throat, runny noses, body aches, fatigue, diarrhoea, nausea and vomiting.

Treatment of SARS and H1N1

Most cases of swine flu don’t actually require medication or treatment and consultations with a doctor are not needed unless severe medical complications arise. Individuals can still go on with their everyday lives and carry out their daily activities. This is in direct contrast to suspected SARS infected individuals who should be checked right away and if found to have the virus, they should be kept in isolation at the hospital and receive urgent medical attention.

The World Health Organization (WHO) recommends isolating SARS infected patients and using barrier techniques like filter masks and goggles to prevent further spread of the virus [2]. Supportive care to relieve symptoms of the infection is usually also administered. Treatment may include antibiotics to treat bacteria causing pneumonia, antiviral medicines, and high dosages of steroids to reduce swelling in the lungs as well as breathing support in the form of oxygen and mechanical ventilations. However no form of drug or antibiotic appears to be effective against SARS. On the other hand, two of the commonly used drugs for treating H1N1 include oseltamivir and zanamivir however they are commonly reserved for people who are at high risk for complications from the flu [6]. Most H1N1 infections can be fought off without the need for medication. Common treatment is usually for relief of symptoms and this includes getting plenty of rest which will aid the immune system in fighting off the infection. Infected H1N1 individuals should keep hydrated by consuming lots of fluids that will aid replenishment of the body’s nutrients. Medication for relief of headaches and sore throats can also be taken.

Prevention of SARS and H1N1

There are a range of ways to prevent the spread of SARS. Reducing contact with infected individuals known to possess the SARS virus will definitely lower the risk of diseases. Direct contact should be avoided with people who have SARS until at least 10 days after their fever and related symptoms have disappeared.  Travel to places where uncontrolled SARS outbreaks are commonly known to occur should also be avoided. Maintaining hygiene of the hands by washing and cleaning with an alcohol-based sanitizer is essential in the prevention of SARS. Infected individuals should always cover their mouth and nose when sneezing and coughing as droplets released into the air via coughing and sneezing are infectious [4].  Food, drink and used utensils should not be shared and commonly touched surfaces should be regularly cleaned with an EPA-approved disinfectant. There is currently no vaccine against SARS however scientists have found a way to disable a part of the virus that allows it to hide from the immune system. This could lead to the development of a vaccine in the future.

Prevention of H1N1on the other hand is usually is done via receiving a yearly flu vaccine. In addition, other ways to aid prevention include maintaining hand hygiene, not touching the nose, mouth or eyes after touching commonly used surfaces. Avoiding large gatherings during the flu season is also a good idea to prevent contraction of H1N1. In addition, being wary of when the flu season begins as well as taking note of any other public health recommendations from the CDC, WHO and any other governmental public health institutions will aid individuals in taking the correct precautions [6]. 

Summary of major differences between SARS and H1N1 viruses