Historic reference

The infectious nature of contagious rhinitis (common cold) was proved in 1914 by W.Kruse and confirmed in 1916 by G.Foster. After that, especially after 1952, the virus agents were repeatedly isolated but their etiological role remained unproved and only in 1960 in Solsbery D.Tyrell proposed a new virus cultivation method and isolated a whole group of them during 1961 and 1962 and proved their etiological role. They were named rhinoviruses after the proposal of C.Andrewes. In 1963 rhinoviruses were included into the family of picornaviruses.

Etiology

The rhinoviruses of the human include 114 serotypes which cause an acute respiratory disease without an expressed intoxication. The virus genome is represented by non-fragmentary filament of the RNA. The viruses inactivate at a temperature of 56 °Ñ quickly in 10 minutes. They die at drying in the air in several minutes.

Epidemiology

The rhinoviruses are widely spread and affect all the age groups of people all the year round. The human viruses develop only in humans, no sensitive laboratory animals have been found, sometimes it is possible to infect a chimpanzee. The strains, which are cultivated on the human's cells, were named H-strains, and the ones on the monkey cells - M-strains. The virus replication takes place in the epithelial cells of the nose and they are excreted with the nasal discharge during 2 weeks. The virus is airborne. The transmission from the hands of an infected person to the hands of the susceptible ones is possible, and then an auto-infection of the nose or conjunctiva occurs.

Pathogenesis

The disease development mechanism has been studied on the volunteers and on the organic cultures. The possibility of the disease development was shown during the experiments on the volunteers when the virus was dropped into the nose or rubbed in the mucous membrane of the nose or eye, whereas rubbing into the back wall of the throat or insertion through the mouth did not cause the disease. The virus was found in the nasal discharge in 24 hours or maximum in 3-4 days. The rhinoviruses can join other pathogens of the lower respiratory tract worsening the course of them. The virus-bacterial associations are discovered quite often.

Clinical manifestations

The incubation period lasts 2-3 days. The disease starts with sneezing, feeling of dryness, tickling in the throat, pain in the throat and slight cough. From the first hours of the disease the leading symptom is rhinitis with abundant serouse discharge,

196 Infectious diseases

which is of a watery character in the beginning, then it becomes slimy and thickly mucopurulent. On average rhinitis lasts 6-7 days but it can be prolonged up to 14 days. During this period the patients complain of a feeling of heaviness and nagging pain in the sinuses. The skin at the nose entrance gets macerated, the herpetic eruption develops on the lips. The mucous membrane of the front part and back wall of the throat becomes moderately hyperemic, slightly edematic. The small granularity develops in the area of the soft palate. The sclera vessels are usually injected, the conjunctiva is hyperemic, and the eyes may be watery.

The symptoms of intoxication are not typical of the rhinoviral infection. The general condition is slightly affected. The patients mention a slight malaise, headache in the forehead area. The body temperature remains normal or slightly increased during 1-2 days. The picture of the peripheral blood does not change.

Complications

The joining of the bacterial flora causes the complications: sinusitis, otitis, bronchitis, and pneumonia.

Diagnosis

The rhinoviral infection is clinically diagnosed in case of the expressed rhinitis with abundant rhinorrhea and pharyngitis, which develop during the first hours of the disease without any intoxication symptoms. The confirmation of the diagnosis is based on the laboratory investigations. The material collection and the methods of the investigation are similar to the ones in other viral infections of the respiratory tract.

Differential diagnosis

The problems in the differential diagnostics of the diseases which form this group are due to the fact that different viruses can cause similar clinical syndromes and first of all the syndrome of the acute disease of the respiratory tract.

The differential diagnostics is possible only in case of the typical course of the disease during the clinical recognition of the nosologic forms taking into consideration the peculiarities of the location of the pathological process, the degree of the toxicosis, the presence and expressiveness of the catarrhal manifestations as well as changes in other organs and systems.

Someimes, in contrast to influenza in the adenoviral diseases the local limited outbreaks are registered, the incubation period in the infected patients is longer, the catarrhal manifestations with an abundant discharge are considerably expressed, there are typical changes in the fauces, the lymph nodes, liver and spleen are enlarged, relapses occur later.

In contrast to paragrippe the onset of the adenoviral diseases is often acute, the exudative component is more expressed, there is lymphoadenopathy one-side conjunctivitis.

Acute respiratory viral diseases

Treatment

Only symptomatic treatment is available for rhinovirus colds at present. Penicillin and other antibiotics have no place in therapy, since they neither ameliorate the viral illness nor reduce the frequency of bacterial complications.

Rest, hydration, nasal decongestants, saline gargles, and cough suppressants remain the mainstay of treatment. Constitutional symptoms are not usually prominent with rhinovirus infection, but will respond to aspirin and acetaminophen when present. Nasal decongestants may be used on a regular basis during the acute stage of illness. The regular application of a petrolatum-based ointment helps prevent painful maceration of the nares. Patients with secondary bacterial sinusitis or otitis media require appropriate antimicrobial therapy.

Prophylaxis

No effective vaccine is available.

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Control questions:

1. Etiology and epidemiology of acute respiratory viral diseases.

2. Pathogenesis of acute respiratory viral diseases.

3. Clinical manifestations of parainfluenza, adenoviral infections, other acute respiratory

viral diseases.

4. Complications of parainfluenza, adenoviral infections, other respiratory viral infection.

5. Laboratory methods of diagnosis: the serological, bacteriological and immunefluorescent.

6. Criteria of diagnosis.

7. Differential diagnosis of acute respiratory viral diseases.

8. Treatment of acute respiratory viral diseases.

9. Preventive measures in spot of disease outbreak.

4.

Infectious diseases

Date: 2014-12-21; view: 1148