Rhinovirus

Rhinoviruses are viruses that contain ribonucleic acid. They are most often the causative agents of acute respiratory viral infections. Rhinoviruses are the culprits of rhinitis, pharyngitis and bronchitis. Very rarely, rhinoviruses cause more severe respiratory tract infections. However, there are cases when due to them, bronchial asthma develops in a child or chronic bronchitis in a person of mature age, can lead to an average otitis and sinusitis; they can also aggravate asthma, cystic fibrosis.

[1], [2], [3], [4], [5]

Causes of the rhinovirus infection

Rhinovirus (RV) is a member of the family of Picornaviruses. There are more than 100 different subtypes in 3 main groups, classified according to the specificity of the receptors: intercellular adhesion molecule-1 (ICAM-1), low-density lipoprotein receptor, and cellular sialoprotein receptors.

More than a thousand serotypes of rhinoviruses are known to science. Despite this diversity, the structure of the virus is very simple - it contains only ten genes, while the human has more than 20,000 genes. The icosahedral capsid of 12 pentamers contains 4 viral proteins.

However, such a primitive structure of rhinovirus does not in the least hamper immunity and infect humans. This type of virus is very common. In areas with a moderate climate, epidemiological outbreaks of diseases provoked by rhinoviruses are often recorded early in the fall and in spring. Single cases are observed continuously, regardless of the time of year. In the tropics, the maximum number of cases is recorded during the rainy season.

[6], [7], [8], [9]

Risk factors

• Smoking increases the risk of respiratory infections by about 50%.
• Newborns or old people are at risk, perhaps because of reduced immunity.
• Non-compliance with personal hygiene.
• Anatomical, metabolic, genetic and immunological disorders (eg, tracheoesophageal fistula, congenital heart defects, cystic fibrosis, or immunodeficiency) increase the risk and severity of the infection.

[10], [11], [12], [13], [14]

Pathogenesis

Rhinoviruses have different transmission mechanisms. Most often - direct contact or aerosol path. The entrance gates are the mucous membrane of the nose and conjunctiva. The main receptor of interaction in the human body with rhinovirus are ICAM-1, which are in large quantities in the posterior nasopharynx. Contrary to popular belief, kissing, ordinary conversation, coughing does not contribute to the spread of the disease.

Rhinoviruses are resistant to cold, but die due to heat, lack of moisture and antiseptics. You can get infected with a virus when you are in contact with a patient whose rhinovirus is present in the discharge from the nose. Rhinovirus spreads by airborne droplets. The variety of rhinoviruses ensures their invulnerability. A medical preparation or vaccine that successfully infects the protein envelope of a given strain is powerless in combating strains having the same protein but different structure. And when the strain of the virus has at least some resistance to the drug, natural selection and mutation will bring about the appearance of strains that will be absolutely resistant to the action of the drug.

Rhinoviruses attack not so many cells and harm from them is not so much. Then why such complications? The point here is the peculiarities of the mechanisms of immune defense. Affected cells produce special molecules, cytokines, which serve as a signal for triggering the cascade of cellular immunity reactions. It is because of them that we have such a bad feeling. Cytokines are the culprits of inflammation in the throat and abundant discharge of mucus. Feel healthy, you can not at all when immunity will defeat the rhinovirus, but only after the immune system begins to work as usual.

Today, doctors do not have the means to fight rhinoviruses effectively. Vaccinations are practically useless. No drug is capable of destroying the virus. The mistake of many is the intake of antibiotics, which are effective in fighting bacteria and are absolutely powerless in dealing with viruses. Often doctors prescribe antibiotics, even if they do not have confidence in the nature of the disease: it is a viral infection or bacterial infection. Careless treatment with antibiotics encourages the development of drug-resistant bacteria.

We greatly underestimate rhinoviruses. They have many types and science only begins to comprehend their diversity. At the end of the last century, scientists discovered several dozen strains that were attributed to two large genera. In 2006, scientists discovered a strain of rhinovirus in the United States, which was not related to any of these genera. And then it turned out that this is a representative of one more, the third kind, which is also very common. In different areas genes of strains of rhinovirus almost do not differ. This fact proves the very rapid spread of this third kind, which was called HRV-C.

Rhinoviruses have a genetic nucleus, which varies very little. But some genes of viruses change very rapidly. Scientists have found out that they are necessary for the survival of rhinoviruses, who entered the battle with human immunity. After the body began producing antibodies to cope with one strain of the virus, it is still vulnerable to other strains, as these antibodies are powerless against their protein envelope. The hypothesis is confirmed by the fact that a person is infected each year with several different strains of rhinovirus.

Despite these facts, some representatives of the academic world are optimistic about the future and believe that it is possible to develop a cure for rhinovirus. Since rhinoviruses have the same genetic nucleus, it can be assumed that it can not mutate. That is, rhinoviruses, whose mutation touched the nucleus, die. When people find a way to influence the core, the disease can be defeated.

But is there any sense in doing this? Rinovirus is dangerous because it opens the way to more dangerous pathogens. However, he himself is relatively safe. A week later the infected person already forgets about the symptoms, and 40% of those tested, who have found out the rhinovirus, did not even know about it - he did not show himself.

Scientists even recognize the beneficial effect of rhinovirus on the body. The collected data confirm that children who have survived relatively safe viral, including rhinovirus, and bacterial infections, are less exposed to immune disorders in adulthood. Rhinovirus, we can say, trains immunity, so that he does not react too actively to minor threats, and was able to concentrate on really serious dangers. Therefore, it is worth considering and, perhaps, changing the view on rhinoviruses: look at them not as enemies, but as wise trainers.

[15], [16], [17]

Symptoms of the rhinovirus infection

The incubation period ranges from 12-72 hours to 7-11 days.

Symptoms of rhinovirus infection are reduced to signs of a common cold. Infection develops asymptomatically for 2-4 days, and then there is pronounced rhinitis with strong discharge from the nose and pharyngitis with no symptoms of toxic damage. In some cases, the vessels of the conjunctiva and the ocular membranes are affected.

Headaches, body aches and other disorders characteristic of influenza, with ARVI are less evident. The temperature of the body does not grow so often and it does not happen as high as in the case of influenza or adenovirus damage. After two or three days, the symptoms lose their severity, but persist for up to a week.

Other symptoms of rhinovirus:

• Dryness in the nasal cavity or irritation.
• Nasal congestion, sneezing.
• Annoying dry cough.
• Hoarseness of voice.
• Abundant discharge from the nose of watery or mucopurulent (yellow or green).
• Painless enlargement of the lymph nodes.

The final recovery after rhinovirus in young children may come even later - after 14 days.

Colds and rhinovirus infections can increase the risk of stroke in children. Conclusions of the Hills study and colleagues from Northern California conducted between 1993 and 2007, which covered about 2.5 million children, showed a significant effect of cold infections and upper respiratory tract infections in the first 3 days of the disease on the risk of stroke in children.

Complications and consequences

Complications of rhinovirus are: otitis media, sinusitis, chronic bronchitis, exacerbation of chronic respiratory diseases.

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Diagnostics of the rhinovirus infection

An accurate diagnosis can be established using laboratory diagnostic methods when rhinovirus is cultured on human cell cultures. Immunofluorescence is also used, which detects the antigen in particles of the epithelium of the nasal mucosa. The most accurate diagnosis is given by the neutralization reaction with paired blood sera.

[22], [23], [24], [25],

Treatment of the rhinovirus infection

Rhinovirus infections are relatively safe and quickly recede. Therefore, the treatment is reduced to alleviating the symptoms and taking measures so that the virus does not spread.

The basis of treatment is rest, copious drinking and taking medications that will ease the painful condition. In a room it is necessary to maintain a comfortable temperature and humidity. This will help calm the irritated nasopharynx and facilitate breathing. For the duration of the illness, alcohol and smoking should be excluded.

It is impossible to defeat a virus with the help of a single drug, but if you use complex treatment, you can help the body to cope faster with the rhinovirus infection.

As the clinical picture of rhinovirus infection is very similar to the manifestations of other types of acute respiratory viral infections, most often use broad-spectrum antiviral drugs. Drugs directed action is worth using only after the diagnosis is confirmed. All lesions of the respiratory tract by viruses (rhinoviruses, influenza, parainfluenza, adenoviruses, enteroviruses or coronoviruses) are treated by one algorithm.

1. Taking antiviral drugs:

• Arbidol (stops the penetration of viruses into the cells of the epithelium). It can be taken from the age of two. Children under 6 years are prescribed 2 tablets a day, at the age of 6 to 12 years take 4 tablets, adults - 8 tablets. The course of therapy is 5 days;
• Isoprinosine - the recommended daily dose is 50 mg / kg. It is necessary to distribute it for 2-3 reception. The course of taking the drug should last at least 5 days;
• Lokferon, Bonafton, Oxolin Ointment - these drugs are intended for topical use. They inhibit the activity of viruses and are administered intranasally;
• Ribavirin - the course of treatment is 5-7 days. It is prescribed from 12 years in a dosage of 10 mg / kg.

2. Reception of immunomodulators, which suppress the reproduction of viruses and stimulate the immune response of the organism.

• Interferon-α is taken with 5 drops in half an hour for 4 hours. Then the number of receptions decreases to 5 times a day. The course of treatment is 5-7 days;
• Viferon in suppositories - pawned 2 times a day.

3. Reception of immunostimulants.

• Cycloferon. At the age of 4, one tablet is prescribed per day, from 7 to 11 years - 2 tablets, adults take 3 tablets;
• Anaferon can be taken even the smallest. He is prescribed to children who reached the age of 6 months: on the first day 4 tablets, then - 1 tablet 3 times a day for 5 days.

4. Elimination of the symptoms of the disease:

• taking antipyretics (Nurofen, Paracetamol);
• taking medications for cough. When prescribing the drug, the doctor takes into account the nature of the cough and the place where it is localized;
• to facilitate breathing, the nose is washed - AquaMaris, Humer or hypertonic solution;
• To eliminate edema intranosally drip Pinosol or Xylen.

Forecast

The prognosis for rhinovirus infection is favorable in most cases. Complete recovery is usually observed for 7 days in adolescents and adults, and for 10-14 days in children. Sometimes a child's cough may persist for the next 2-3 weeks.

[26], [27], [28]