With the World Health Organization declaring 2019-nCoV (novel coronavirus) a global health emergency, Dr Ioanna G Alexandropoulou takes a look back at the spread of respiratory viruses from recent history.

Whether in people, pigs or poultry, due to its airborne nature influenza can spread quickly. Here with information on how to protect ourselves against emerging respiratory viruses is Dr Ioanna G Alexandropoulou.

During the last decade, new respiratory viruses of concern occurred worldwide, mainly with high mortality. In 2011 was the virus influenza subtype A (H3N2)v, which was derived from pigs was detected in humans. The following year Middle East respiratory Syndrome coronavirus, or MERS-CoV was detected in countries of the Arabian Peninsula. The influenza virus A (H7N9) was detected in 2013 in China. Recently, new influenza viruses emerged:  A (H10N8), A (H6N1) and A (H5N8) in SE Asia.

It seems that the ability of certain viruses to cross the species barrier and infect humans, in conjunction with increased human-animal contact, was the main reason for the emergence of SARS coronavirus in 2003 and MERS in 2013.

In parallel, the increased alertness of public health authorities and the WHO combined with the new diagnostic tools for viral infections, has contributed to the increased possibility of detecting cases of emerging viruses. In previous outbreaks of respiratory infections, even fatal ones, was not always possible to be diagnosed, thus, many emerging viruses were not always known.

Endemics and pandemics

Acute respiratory infections can be endemic or pandemic.

Etymologically, the word endemic comes from a combination of two Greek words: endon, meaning within, and dimikos, meaning municipality or community. By understanding this linguistic root it becomes clear that the disease incidence of an endemic is localised to a specific population or certain community. The term endemic also characterises the appearance of a disease, which occurs continuously in time in the same area and has a constant effect in that region or group of people who live in that region.

A pandemic, on the other hand, is the large-scale spread of an epidemic disease affecting a very large percentage of the population worldwide.

The word pandemic refers to diseases of global importance, such as AIDS and Malaria.

The outbreak is the spread of a disease observed in a large group of people in a certain geographical area. If a disease reaches an epidemic this means highly contagious spreading e.g. epidemic viral gastroenteritis.

The acute respiratory infections are the main causes of morbidity and mortality worldwide, especially in paediatric populations. Approximately half of these are due to respiratory viruses, with the most important, at least from a public health perspective, being collectively the flu viruses. They are responsible for seasonal flu epidemics each year, which can affect thousands of people throughout winter in each country.

The annual visitor

Influenza is an infectious disease of the respiratory tract, which can cause mild to severe illness and can even lead to death, depending on the virus strain and the population group that it infects.

Influenza is also responsible for unpredictable pandemics with significant loss of life and large economic costs. Influenza has struck globally throughout history: the Spanish flu of 1918, as well as influenza pandemics in Asia, Hong Kong and Russia in 1957, 1968 and 1977, respectively.

Origins of influenza

According to literature, influenza viruses primarily infect birds, but can also infect mammals. Therefore, there is an enormous reservoir of influenza viruses in nature, with the majority of them not capable of affecting humans.

Nevertheless, when influenza viral genes derived from birds and mammals, pigs in particular, combine with human strains of the virus, this creates new subtypes of influenza virus that can infect humans and cause severe disease. If these viruses then achieve the human-to human transmission route they could cause pandemics.

The flu wave

The endemic wave of flu is spreading in Europe, USA and Canada and based on all data, there is a new, differentiated strain of influenza H3N2. This strain is characterised by increased morbidity and increased frequency of serious complications, compared to other influenza strains.

The situation in Greece

In Greece according to the Hellenic CDC, during 2013-2014, 338 cases were recorded that required hospitalisation in the ICU. A total of 145 of the hospitalised patients eventually died from complications of the flu.

The epidemic wave of influenza in Greece generally takes place the period between January and March, with peak activity during February and March. This winter just gone, however, the wave began earlier – almost in December.

Similar was the situation across Europe. According to data recorded by the European Centre for Disease Control (ECDC) a significant increase in flu cases was recorded in late December throughout Europe. In addition, according to the European Observation System for Morbidity in primary care, in European countries the influenza morbidity level increased week on week.

Influenza’s symptoms

Influenza is characterised by the sudden onset of severe symptoms such as high fever, severe fatigue, myalgia, arthralgia, headache and cough that can last between two and seven days. Children may have gastrointestinal symptoms such as nausea, vomiting and diarrhoea, while in adults the symptoms are less frequent.

Complications of influenza

One of the major complications of influenza, which in some cases leads to death, is pneumococcal pneumonia. Sometimes, even the flu virus itself can cause pneumonia. Other complications are also asthma attacks in people suffering from bronchial asthma, exacerbation of chronic bronchitis, worsening of heart failure or diabetes. Children may also be co-infected and suffer from sinusitis and otitis.

How infection occurs

As the nursery rhyme goes – coughs and sneezes spread diseases. When infectious persons sneeze and cough their virus becomes airborne and can be inhaled by others in the surrounding area, hence the importance of covering the mouth and nose when sneezing and coughing. Droplets can also settle onto surfaces, further spreading the transmission.

At risk groups

In general, influenza viruses cause respiratory infection cases that run for just a few days. Nevertheless, in some cases there can be serious complications, especially for people of high risk groups such as:

  • Those with cardiovascular disease or chronic lung disease
  • Organ transplantation
  • Pregnant women regardless of gestational age
  • People with metabolic, kidney and neurological diseases
  • Children who take aspirin long term, for conditions such as Kawasaki disease and rheumatoid arthritis, as they face the possible risk of developing Reye syndrome after influenza
  • People with immunosuppression
  • People with obesity
  • People in close contact with infants of less than six months or
  • Carers of individuals with underlying disease
  • Closed populations such as educational establishments, hospitals, prisons and offices
  •  Workers in healthcare facilities
  •  People aged 65 years and older
  •  Infants

Preventative measures

The following are general guidelines for personal protection and restricting the spread of all respiratory viruses:

  1. Cover your mouth and nose with a tissue when coughing or sneezing, then throw the tissue to the bin and wash your hands.
  2. If you do not have a tissue do not cover your nose/mouth with your hand – use the medial elbow. If you do not manage to do this, then wash your hands immediately.
  3. Wash your hands with soap for at least 15 to 20 seconds or with a special alcohol solution, or use wipes impregnated with alcohol. Rub hands together until dry. Afterwards, do not rinse with water.
  4. Wash your hands often when you or people close to you are sick.
  5. Wash your hands before you handle food utensils.
  6. When you are away from home during an epidemic period, you should carry antiseptic solution or wipes.
  7. When your hands are not washed, you should never put them in the mouth, nose or eyes – nor should you touch things that will go in the mouth, nose or eyes.
  8. Try to have a good physical condition by eating healthily, taking exercise and having adequate sleep.
  9. During epidemics, you and your children should avoid non-essential contact with other people, especially while you are infectious.
  10. Children should learn these health and protection measures, in order to apply them in school and anywhere else outside the home.

In the event of clinical symptoms seek help, advice and treatment from the healthcare services.

Population groups at high risk of developing a complication of influenza, together with those in enclosed populations, should be vaccinated in a timely manner. It should be noted that the vaccine against influenza must be timely because it provides protection around two to three weeks after the completion of vaccination.

What should be done?

There is a need for special awareness in the community for the scrupulous observance of hand and respiratory hygiene measures. In addition, doctors should administrate timely antiviral therapy to high risk groups and persons with severe infections.

It is also advised that patients seek medical advice in the event of prolonged or severe influenza symptoms, even if they are not at increased risk of complications. The global alert to prevent pandemic influenza and other respiratory infections should lead to a better informed population and should increase the appropriate preventive, diagnostic and therapeutic measures.