Understanding Swine Flu
Tufts health sciences experts comment on the recent concern around swine flu.
Boston [06.01.09] Over the past several weeks, health officials around the world have responded to the emergence of a new influenza strain and fears of a pandemic. While the initial fervor has died down, some scientists are concerned about a reemergence during the next flu season. According to a group of Tufts public health experts, however, the best prescription is to be cautious but realistic.
The H1N1 influenza A virus, known commonly as "swine flu," began dominating the headlines in April as some people began dying from the virus, which originated in Mexico. Context, however, is critical. While there have been a handful of deaths attributed to swine flu in the U.S., according to the Centers for Disease Control, about 36,000 people die from influenza every year in the United States.
Basic hygiene, including hand-washing and covering your mouth when you sneeze, has been advised as the best strategy for those concerned about contracting the illness.
We asked public health experts from the School of Medicine and the Cummings School of Veterinary Medicine to comment on what the public should keep in mind as H1N1 continues to be a concern.
Associate Professor Joann Lindenmayer
Department of Environmental and Population Health
Cummings School of Veterinary Medicine
Balancing Vigilance with Realism
From my point of view as a public health veterinarian, the main point to emphasize is that the genetic makeup of the virus is still being elucidated and only part of it may be identical to H1N1 influenza A viruses found in swine, therefore it's a misnomer to call it swine flu and continuing to do so may actually do a disservice to people who consume pork and swine producers.
There is limited epidemiological evidence to link the present H1N1 influenza A virus now spreading in people to swine; although 'ground zero' for the emergence of the virus is located near a swine facility in Mexico, there is no evidence that pigs were sick or that the virus jumped species there.
Swine flu is endemic in the US and has been for decades.It causes a disease among pigs that resembles typical influenza in people. Although aspects of this virus (it's novel; it's being transmitted among people; people other than those with close contact with pigs are unlikely to have any degree of immunity to it) are worrisome, and we should monitor it closely now and in the future, it's also instructive to remember that in the US every year, human influenza kills 35,000 to 40,000 people, mostly the very young and the elderly.The number of human deaths attributed to the H1N1 influenza A virus is one-half of one percent of all deaths caused by annual influenza viruses in the US.The bottom line - be vigilant, be careful, but be realistic.
Professor Elena Naumova
Department of Public Health and Family Medicine
Director, Tufts Initiative for Forecasting and Modeling of Infectious Diseases (InForMID), and director, Health and the Environment, Tufts Institute of the Environment
Flu Vaccine as a Preventive Measure
As it has been documented, the incidence of influenza peaks in cold winter months: outbreaks of seasonal influenza begin in the late fall to early winter and dissipate in the spring. Annual epidemics begin abruptly, peak within two to three weeks, and last for five to ten weeks. Seasonal waves of influenza travel over large geographical regions covering many climatic zones in a relatively short period of time.
Precise mechanisms for emergence of new strains, influence of local sources and factors in the spread of infections are still not well understood. The arrival of a new strain might change the typical seasonal pattern of influenza. It is likely that with an increasing circulation of a new swine flu strain, the onset of a seasonal increase may occur earlier than usual. Vaccination programs achieve the best protective effect if vaccination is administered before the outbreak is in progress and if the majority of people in the community are vaccinated.
Professor George Saperstein
Chair, Department of Environmental and Population Health
Cummings School of Veterinary Medicine
Effect on the Animal Population
This outbreak demonstrates again that although there are many disease causing organisms that co-exist with one host, there are also quite a few which can adapt to a variety of hosts. From a biological perspective such pathogens could care less whether their new home is man or animal.Although influenza is generally a mild disease in swine, I am concerned that people infected with this new strain of H1N1 may inadvertently infect pigs. Therefore it is important that people who become sick with symptoms of influenza should avoid all contact with pigs until they are no longer contagious.