Contagion
The AH1N1 influenza virus spreads in the same way as seasonal influenza viruses, ie:- directly: through the respiratory and saliva droplets emitted with cough and sneeze;
- indirectly: through hands coming into contact with objects and surfaces contaminated by secretions of infected people (door handles, handrails, tables and benches, taps, sports equipment, etc.), and brought to the eyes, nose or mouth without first be washed.
Influenza viruses (including influenza virus AH1N1) live on surfaces for 24-48 hours; however, after just a few hours the infectivity of the viral particles is significantly reduced, due to exposure to the external environment and to atmospheric agents.
People with influenza, swine or not, are already contagious during the incubation period that precedes the onset of symptoms. The virus can be transmitted from one day before the onset of symptoms up to seven days from the start of these. Children, especially the younger ones, can instead remain contagious longer. Readmission to community life is advisable after 48 hours, and in any case not earlier than 24 hours after the disappearance of the fever (which must be independent of taking medication to keep it low). This period, however, varies according to the clinical picture.
The flu virus affects the mucosa of the upper respiratory tract and attacks the cells of the epithelium of the mucosa itself, within which it penetrates undisturbed.
Once inside, it is subdivided into sub-units ("bits" of viruses): this phase is called "of eclipses", because at this time the virus is not available in a circle. Subsequently, it replicates, frees itself in the respiratory tree after having broken the cells that housed it, invades other cells repeating the whole cycle and spreading the infection. It follows that large areas of respiratory epithelium die, leaving a fragile and very inflamed mucosa, which therefore begins to produce large amounts of mucus.
Symptoms
The flu, including the swine flu, begins after 1-3 days of incubation mostly abruptly (more rarely after 24-48 hours of general malaise and headache), with high fever (around 39 ° C), chills, sense of prostration, loss of appetite and refusal of food, intense headache, muscle and joint pain mainly in the back. Within a few hours, we add sneezing, rhinorrhea ("runny nose"), tearing and photophobia (light intolerance), pharyngodynia (sore throat), burning sensation behind the sternum, coughing first dry and then with mucus. Sometimes nausea, vomiting, abdominal pain and diarrhea are present. The language can be taught.
Younger children are not able to describe the general symptomatology, which in their turn can be manifested with irritability, crying, lack of appetite. In infants, influenza is often accompanied by vomiting and diarrhea, and only exceptionally by fever. Very high fever, red eyes, conjunctivitis, laryngotracheitis and bronchitis are characteristic of influenza in preschool children (1-5 years).
In the elderly, the symptoms of swine flu may have different characteristics, given the presence of other intercurrent diseases, the weak immune response and the different perception of pain. In them, however, the habit of vaccinating helps to mitigate the severity of the symptoms that are, especially in the large elderly, often subtle, with a low fever, an inability to maintain posture, drowsiness, motor incoordination and urine and faeces incontinence. The other illnesses present in the elderly can worsen the clinical picture, and determine metabolic decompensation of diabetes, heart failure, respiratory failure, etc.
An analysis of over 600 cases of influenza A - H1N1 in the US showed that the most frequent symptoms were fever (94% of cases), cough (92%) and sore throat (60%). Furthermore, 25% of patients have had a gastrointestinal symptomatology (diarrhea and / or vomiting) which is usually characteristic of the pediatric age, while in the adult it varies from 6 to 10%.
However, the epidemiological data provided in June 2009 showed a lower presence in the elderly population of H1N1 influenza compared to the seasonal one.
The course is of short duration: after 2-4 days the fever disappears, with sweating and remission of the symptomatology. The respiratory symptoms of swine flu may also persist for a long time (approximately 20 days); the persistence of fever, on the other hand, should lead to suspect a complication.
After the remission of symptoms follows convalescence, characterized by profound asthenia (tiredness, easy fatigability) and coughing, which can last for 1-3 weeks.
See also: Nutrition, medicinal herbs and flu
