Confirmation of the first death from H5N1 in North America came Wednesday from Alberta, marking the first fatal case of the endemic virus in North America, according to federal Health Minister Rona Ambrose. While the illness has claimed 348 victims in the past decade, medical experts tell citizens they need not to fear.
The cause of the Alberta death was confirmed by the National Microbiology Laboratory to be encephalitis. An inflammation of the brain and lining of the brain, which is commonly associated with death from H5N1, according to Dr. James Talbot, Alberta’s chief medical officer of health, was the culprit. “The illness [H5N1] causes in humans is severe and kills about 60 percent of those who are infected,” Taylor said. Adding “No other illnesses of this type have been identified in Canada since the traveller returned from China. This is an isolated case.”
There is no need for panic though. Dr. Neil Rau, an infectious diseases specialist spoke publicly, stating that H5N1 human-to-human exchange is very rare. “You don’t get sustained chains of transmission, where it goes from one person who had contact with the birds to another person, and then again to another wave of people. I think the most that’s ever been seen has been two chains, but most of the time, you don’t actually see close contact giving rise to a sustained spread.” He described the fatal case as an “unprecedented worldwide event.”
The deceased person recently traveled in Beijing, China to visit family and first showed symptoms of the illness on an Air Canada flight from Beijing to Vancouver on Dec. 27. The victim was admitted to hospital on Jan. 1 and died two days later. The death was made public on Jan. 5 by the Public Health Agency of Canada. Health officials say that individuals that were on the same flight will be contacted and “reassured” of the low transmission risk between humans.
It is unclear exactly how the person contracted the illness, as they did not leave Beijing and did not travel to any farms or markets. Family members of the victim have been treated with Tamiflu as a precautionary measure.
H5N1 symptoms in humans include sore throat, aching muscles, abdominal pain, chest pains and diarrhea. The flu can progress very quickly into severe respiratory illness, seizures, organ failure and death. The Alberta case is said to have been difficult to diagnose, as respiratory issues were not present in the victim.
The highly pathogenic sub-type of the influenza A virus crossed the species barrier to affect humans for the first time in 1997 in Hong Kong. H5N1 is an enzootic Avian flu virus, meaning that it is prevalent among animals of a specific geographical area, most frequently seen in certain regions of Asia and the Middle East. It has claimed no victims in the Western Hemisphere and has been previously undetected in North America. For this reason, citizens are advised not to fear. It has maintained in the avian population without the need for external inputs through other species.
The flu strain is present in poultry in two forms, the first of which is of a low virulence and often undetected, with few symptoms, including ruffled feathers and a decrease in egg production. The second form is highly pathogenic and spreads rapidly. It affects multiple internal organs and has a mortality rate that can reach 90 to 100 percent in just 48 hours.
There have been 648 cases in humans in the past decade. These cases were present in 15 different countries, with 384 of them resulting in death. The highest number of overall cases has been in Egypt and Vietnam, though according to the World Heath Organization, there were 38 known cases of H5N1 in humans in 2013, which resulted in 24 deaths, mostly in Cambodia.
The sickness is contracted from coming in contact with infected sick or dead birds, their droppings, or blood. It is also possible to contract H2N1 when subjected to prolonged exposure to infected environments, such as live poultry markets aboard, as well as recurrent exposure to infected persons.
A candidate vaccine, a preventive immunization which contains a preparation of weakened or killed pathogens has been developed by GlaxoSmithKline for the prevention of H5N1. It was approved in the U.S by the FDA as well as in Europe under the name Pumarix. Pumarix is a “mock-up” vaccine which is a special type of vaccine that can be developed to help control a future pandemic. The vaccine is not currently approved in Canada. The seasonal flu vaccine is not effective in preventing H5N1, and the WHO says that the illness must be treated in hospital. The antiviral medication Oseltamivir, which is marketed under the trade name Tamiflu, has been shown to reduce severity by slowing the spread of the virus between cells, by targeting enzymes called viral neuraminidases, which enable the virus to be released from the host cell.
While no recommended travel restrictions are in place, the Public Health Agency of Canada cautions visitors to China to avoid animal markets, poultry farms and contact with birds. They also warn citizens and travelers to ensure that all foods are well cooked, as the virus is very sensitive to heat. The World Health Organization says that the highest risk of H5N1 infection comes from home slaughtering and improper of raw poultry. No further claims are expected to result from the Alberta death, and experts advise against fear-mongering , alarmist behavior.