14 DAY TRIAL // In two new, separate studies using ferret populations, experts have determined that the A H1N1 influenza strain has a very widespread effect on the body, being able to penetrate deep within the respiratory tract, and even as far as the intestines. This find may help explain why the symptoms associated with swine flu are in some points different from those generally associated with the annual influenza outbreaks, caused by less potent strains, Nature News informs.
One of the two studies was carried out at the Center for Disease Control and Prevention (CDC) branch in Atlanta, Georgia, and was led by expert Terrence Tumpey. In the research, whose results are published in the latest online advanced issue of the journal Science, the scientists placed droplets containing three types of swine flu and one type of regular influenza into the noses of ferrets, and then placed the animals either in cages with uninfected ferrets, or in cages that only shared air with others.
One of the major goals of the research was to determine how the strain spreads, how fast, and to what extent it affects the body when it does. Results determined that, on average, the swine flu strains affected a lot more of the lungs than the regular strain, and also that, in some cases, it reached even the intestines. This may help explain why some of the humans infected with the H1N1 strain were experiencing symptoms like vomiting and diarrhea with their infection.
The second study, which was conducted at the Erasmus University Medical Center, in Rotterdam, The Netherlands, came to similar conclusions, showing as well that the viral strain has a large penetration power inside the lungs, far exceeding normal strains. “This is the first indication of how pathogenic [swine flu] really is. In the field that conclusion is hard to draw,” explains EUMC expert Ron Fouchier.
The two studies, however, came into disagreement related to the way the strain was transmitted. While Tumpey's showed that H1N1 failed to transmit very fast from one ferret to the other, Fouchier's revealed that the transmission rates were very similar to those of regular flu strains. The differences, the two say, may come from the fact that they used different types of swine flu, and also from the fact that the animals involved were slightly different. Ferrets are the preferred tool for researchers studying flu, because they develop the same symptoms as we do, which last for about the same time they do in humans.