MEXICO CITY, May 12 2009 (IPS) – Scientists around the world are trying to decipher the influenza H1N1 virus in order to develop a vaccine, while others are tracking its origins to fight its spread more effectively.
Surgical masks have become part of the Mexican police uniform. Credit: Marcos Ferro Tarasiuk/IPS
Laboratory tests show that the virus strain initially believed to be swine-based is actually a subtype of influenza virus A that contains genetic material from swine, human and avian strains. It easily mutates and recombines, which is what makes it potentially so dangerous.
The microbiology laboratory at Canada s Public Health Agency took a step forward in announcing May 6 that it had decoded the genetic sequence of three samples of the H1N1 virus collected in that country and in Mexico.
This virus already existed. It has been mutating and will continue to mutate. My hypothesis is that we are faced with several subtypes of A/H1N1, pulmonologist Fernando Cano, former director of Mexico s National Institute of Respiratory Disease (INER), told Tierramérica.
There have been several documented cases of swine flu in humans, including a non-fatal contagion in 2007 that affected 12 people at a rural fair in the midwestern U.S. state of Ohio, said Cano, who is coordinator of the bioethics and clinical medicine faculty sponsored by UNESCO (United Nations Educational, Scientific and Cultural Organisation).
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The people affected by that outbreak were tested and it was found that 60 percent had antibodies to fight that flu strain, added Cano, former director of the Autonomous National University of Mexico (UNAM) medical school. According to Cano, the Ohio virus is likely to be an ancestor of the current strain.
In a Tierramérica interview, Eduardo Sada, INER head of microbiology research, pointed to reports from 1957 and 1977 on swine flu in humans. Undoubtedly the original virus and the current one circulated at a low volume for several years until something that we haven t discovered yet triggered the epidemic, he said.
To assert that this H1N1 subtype originated in Mexico at this point is just speculation, agreed Cano and Sada. The virus has now been detected in more than 20 countries.
The first confirmed case of the new virus was in the small, impoverished community of La Gloria, in the southeastern Mexican state of Veracruz. From mid-March to early April, a rare outbreak of flu affected 600 people in the town, located some 10 kilometres from a pig farm.
Medical samples from the sick individuals in La Gloria were sent to laboratories in the United States and Canada. One of them, from a five-year-old boy who presented symptoms on Apr. 1, contained the new virus, said a report released on Apr. 23.
The same report, from Canada s National Microbiology Laboratory, in Winnipeg, confirmed that a woman who died of pneumonia on Apr. 13 in the southern Mexican state of Oaxaca, and who apparently had no contact with La Gloria, had also contracted the virus. But they weren t the only early cases. In the city of San Diego, California, near the Mexican border, a boy fell ill on Mar. 30 with an atypical respiratory illness. A similar case occurred shortly afterwards, involving a girl in the nearby town of Imperial.
The U.S. Centres for Disease Control and Prevention (CDC), in the southeastern U.S. city of Atlanta, analysed samples from both cases and confirmed the presence of the new H1N1 virus.
In 1999, young people and pigs died of a strange virus in Malaysia. It was believed to be Japanese encephalitis , which is transmitted by mosquitoes that feed on both humans and pigs.
After several months of research and the slaughter of hundreds of pigs, the scientists discovered that the problem originated at a farm where some of the animals had eaten fruit remnants that had been contaminated by bats, which are asymptomatic carriers of the virus. Further, it was determined that transmission to humans occurred through pig saliva.
With that information, the authorities were able to stop the spread of the virus, which was dubbed Nipah, although they were not able to eradicate it.
Teams from the World Health Organisation (WHO) and researchers from several countries are trying to track down the origins of the new influenza, popularly known as swine flu . But they agree it will be difficult to determine where it originated.
Cano believes the deaths caused by the H1N1 virus, nearly all of which have occurred in Mexico, are related to delays in medical attention or inappropriate treatment, but does not rule out the possibility that the severe cases may have been caused by variants of this virus strain. In any case, the new virus is generally not very lethal, and that is fortunate, although it should not be forgotten that it could mutate and generate a severe pandemic in the future, he warned.
On Apr. 23, Mexico decreed a health emergency after confirming the presence of the new virus. On Apr. 24, the WHO also declared a public emergency. It then elevated its epidemiological alert from phase three to four, and later to five (out of six).
On May 4, Mexican authorities announced the stabilisation of the epidemic, calling for the gradual return to normal school and business activities, which had been largely paralysed since Apr. 23.
Every year, between 250,000 and 500,000 people around the globe die from the various strains of seasonal influenza that usually present during the colder times of year, says the WHO.
At first, the appearance of the H1N1 virus confused the scientific community, because the strain circulating mostly affected young adults. However, of the more than 1,000 cases confirmed in Mexico, nearly half were people 19 and younger.
Another issue to be clarified is why the people who died from the virus have nearly all been Mexican, and why some of the infected are able to recover without complications or pharmaceutical treatment, while others end up in the hospital.
For now, there are more questions than answers about the traits of the new virus, its origin and its mutation profile, after Canada confirmed that some pigs had contracted the virus from a sick farm worker.
Cano recommended that people continue to get vaccinations against seasonal flu, which even if it does not specifically target the new strain, does provide additional protection.
The H1N1 virus, which is spread in the same way as any other influenza virus, reacts well to antiviral medications if they are administered in a timely manner, though scientists fear new mutations could mean the pharmaceuticals will become less and less effective.
The first analysis by a multidisciplinary team from UNAM and the National Polytechnic Institute, set up to study the virus, confirmed that it has a great capacity to mutate, said microbiologist Antonio Lazcano, who considers it highly probable that there are different varieties of H1N1 circulating in Mexico alongside other flu viruses.
(*This story was originally published by Latin American newspapers that are part of the Tierramérica network. Tierramérica is a specialised news service produced by IPS with the backing of the United Nations Development Programme, United Nations Environment Programme and the World Bank.)