Diagnosis
The focus of the diagnosis of an infection with the swine flu virus is the detection of the virus’ DNA. Nevertheless, it is important to take a thorough anamnesis in a doctor-patient conversation. In this discussion then usually the suspicion on the presence of a flu illness hardens itself.
The treating physician is interested in this discussion in the foreground standing symptomatology, the duration and intensity of these complaints, as well as in the presence of other factors of risk, which represent a risk with an illness with the Schweinegrippevirus. Especially persons with previous illnesses and an immunodeficiency have a higher risk of complications when infected with the virus, which is why this information is particularly important for the attending physician. Also the daily life and daily contact with other ill persons in the close environment of the affected person can be important for the attending physician to estimate the probability of the presence of swine flu.
The medical history is usually followed by a physical examination of the affected person. During this examination, the physician uses a stethoscope to listen to the lungs in order to detect a manifestation of the virus in the respiratory tract and/or lungs. Palpation of the abdomen can also be helpful for the attending physician to assess the involvement of the gastrointestinal tract, typical for swine flu.
Since neither the medical history nor the physical examination can prove the presence of a swine flu infection, another method must be used. By taking sample material, which with a high degree of certainty contains a relevant amount of virus, the diagnosis of an infection with the virus can be made.For this purpose, a smear is taken in the left and right nostril as well as in the throat using one cotton swab each. These three samples are then sent to a laboratory, which evaluates the material.
Alternatively, the treating physician can also take nasal rinsing fluid and send it in. In this case, saline solution is rinsed into the nose and removed again, thus ensuring that the liquid is sufficiently infected with viruses. There is also a rapid test that can be used to diagnose swine flu in the doctor’s office.
As this rapid test is not very accurate, it is still necessary to send in a sample taken from the person concerned after a positive or negative rapid test. However, it can be helpful for an initial assessment and, if the test result is positive, it can form the basis for starting therapy. The laboratory which receives the sample performs a duplication of the DNA material by means of the so-called “polymerase chain reaction”.
If the laboratory detects the genetic material of swine flu in addition to the DNA of the person affected, the infection with the virus is considered confirmed. However, these laboratory tests usually take one to two days to complete, which is why an initial assessment by the attending physician cannot and should not be replaced, especially for people with risk factors. In general, the possibility of infection with swine flu exists between infected animals and humans and between humans and humans.
The infection by the virus of the swine flu mainly occurs via two different pathways. On the one hand, the virus can be transmitted by the so-called droplet infection. This happens for example by coughing or sneezing of affected persons, who transfer the virus in droplets packed from themselves to healthy people.
Even when speaking, microscopically small droplets can pass to another person, which is why close contact with people who have swine flu should be strictly avoided. The second major transmission route of the virus is the smear infection. Here, virus particles can be transferred to door handles or similar from infected persons and then picked up by other people who touch the object.
For this reason, large gatherings of people in confined spaces should be avoided during the main infection period of influenza diseases, and one’s own hand hygiene should be carried out carefully and regularly. Since the virus is still intact even 2 hours after touching the surface (at 22°C room temperature), surfaces that are often touched by many people (for example in public transport) should be handled with particular care and attention. During the pandemic in the 2009/10 season, mouthguards were distributed in particularly affected regions to keep the infection rate in the population low.
Overall, swine flu is considered to be more contagious than seasonal “winter flu”, which is why infected persons should be treated more carefully. It is assumed that a person is normally contagious for the surrounding area about 24 hours after the outbreak of the disease (i.e. the onset of symptoms). The period of potential infection can then last up to 7 days. In exceptional cases, it is even possible that infection may occur during the incubation period of the disease, i.e. after infection but before the symptoms appear. The incubation period of swine flu is about 2-3 days.
