The outbreak of swine flu (Influenza A(H1N1) Virus) took the world by storm a little over a week ago with the epicentre in Mexico. Over the past weekend we have learnt from the Mexican health authorities that the virus has peaked and they don't expect a further increase in the number of cases as has been seen since March 18 when health surveillance began picking up cases of an influenza-like-illness in the country.
Nations around the world mobilized early last week when the World Health Organization (WHO) declared that swine flu constituted a public health emergency of international concern.
Influenza also known as the flu, is an acute viral infection where one comes down with fever, chills, headache, muscle pains and usually cough, with or without sore throat or other respiratory symptoms. For most people, the flu is an unpleasant but self-limiting and not life-endangering illness, but in some people it may be more severe, or complicated by other infections such as bronchitis and pneumonia.
Pandemic flu is a type of influenza that spreads rapidly to affect most countries and regions around the world. It is more serious than the ordinary flu and can affect as much as a quarter of a nation's population. Unlike the ordinary flu that occurs at the beginning and end of the year, a pandemic flu can occur at any time of the year. Pandemic flu has occurred throughout history, three times in the last 100 years resulting in many deaths.
Pandemics of flu are due to the emergence of a new flu virus which is different from strains that are already circulating. Very few people if any will have immunity to this new virus. This allows it to spread rapidly and widely and to cause more serious illness. Each pandemic is different, and until the virus starts circulating, it is impossible to predict its full effects.
An influenza pandemic is thought most likely to emerge from South East Asia, but could start anywhere in the world and as can be seen, right in the Americas - Mexico. The last global concerns for an influenza pandemic were with avian "bird" flu back in 2003. The bird flu virus was isolated from a farmed goose in China back in 1996 followed by the first known instance of human infection of the virus in 1997 in Hong Kong.
The birth place of recent pandemics has been China or the Far East. The close proximity of humans, ducks, other poultry and domestic pigs in farming communities facilitates mingling of human and animal viruses which may then exchange genetic material, resulting in a new flu strain.
The time between most recent influenza pandemics have varied from 10 to 40 years, the last being in 1968/9.
Today we are at phase 5 of the pandemic alert system. The WHO raised the global phase level last week Wednesday after it saw the virus was spreading too many countries around the world. This pandemic alert system is similar to the hurricane category scale which goes from one to five based on the intensity of a hurricane with five being the most intense.
The pandemic alert system has six phases. Phase one and two is the inter-pandemic period; phases three to five is the pandemic alert period; and phase six is pandemic period.
The WHO has defined phases in the evolution of an influenza pandemic which allows a step approach to preparedness planning and response by countries around the world leading up to a declaration of the onset of a pandemic.
Does the peak in so-called "swine flu" Influenza A (H1N1) virus in Mexico mean that we won't see the onset of a pandemic? WHO officials have said on Sunday that we can't lower our guard because there is a high possibility that the virus will come back. Even though according to Mexican authorities, the evolution of the epidemic is now in its declining phase, nations around the world will continue to monitor their communities very closely for any increase in flu-like-illnesses.
Countries around the globe will continue to implement steps and take measures according to their pandemic preparedness and response plans.
Roddy Heyliger
