From Big Medical Encyclopedia

MULTI-INFECTIONS [late lat. infectio infection; synonym: the associated infections, satellite infections, mikstinfektion) — the process developing in a macroorganism or (and) separate cells of eukaryotes, prokariot at the combined influence of two and more activators: viruses, bacteria, spirochetes, mycoplasmas, rickettsiae, chlamydias, fungi and protozoa.

Among inf. diseases of the person on S.'s share and. about 50% of cases are necessary. Along with difficulty of diagnosis, prevention and S.'s treatment and. are quite often characterized heavy a wedge, a current and high mortality.

First observations of S. and. and associations of microorganisms belong to L. Pasteur who established in 1865 um that the infectious disease of silkworms is caused by the elementary Nosema bombycis and fungi of Botrytis bassiana. L. A. Ziljber in 1934 allocated a special form of interaction of viruses with cells, to-ruyu it designated the term «allobioforiya» — a carriage of other life. In a crust, time this term is meant as long preservation and reproduction of these types of living beings or fragments of their genomes in the nature; at the same time one look — a cell of prokariot (see. Prokariotny organisms ) or eukaryotes (see. Eukariotny organisms ) — is the carrier of other look — a noncellular life form (one or several viruses or their genomes) and vice versa, the virus can keep fragments of a genome of cellular life forms as a part of the genome.

At S. and. (also, as well as at monoinfections) three factors have the defining value: biol. properties of the activator, feature of an organism of the owner and influence of the environment (in relation to the person — also social conditions). However interaction of several inf. agents with multicellular or a unicell is difficult and qualitatively new process, to-ry it cannot be expressed by simple summing of the signs characteristic of each of the monoinfections making it. Thereof S. and. it is necessary to consider as a special form inf. process, the main patterns to-rogo (types, forms, and the levels C. of the item, factors promoting their formation in the conditions of in vitro and in vivo, the result of interaction of assotsiant — activators C. of the item, feature of diagnosis, prevention and S.'s treatment and., etc.) are a subject of studying of a biogeocenology — the section of ecology devoted to hl. obr. to relationship between components biogeocenoses (see).

Page and. proceed in acute, chronic persistent and latent forms. Special case of S. and. — consecutive infection (superinfection), when to developed inf. diseases joins new inf. disease. Quite often consecutive infection arises at disturbance of symbiosis of a macroorganism and its autoflor (see. Symbiosis ), owing to what there is activation of opportunistic microbes (see) — staphylococcus, colibacillus, etc.

Activators C. and. there can be different representatives one this. microorganisms (e.g., a virus — a virus) or the activators relating to various taxons (e.g. a virus — a bacterium, a bacterium — protozoa, etc.). Page and. can be implemented at molecular level, intracellularly, within one population of cells or an organism. S.'s example and. at molecular level the so-called integration viral infection can serve, at a cut genomes of two and more oncogenous viruses (e.g., viruses of sarcoma and a leukosis of birds) are built in a genome of a cell.

Fig. 1. Diffraction patterns of microorganisms at multi-infections: and — an influenza virus (1) on a surface of a mycoplasma (2); — viruses of vesicular stomatitis (1) on a surface of the virus of a variolovaccine (2) adsorbed on a cell (3); x 150 000.
Fig. 2. Diffraction patterns of the cells infected with various viruses: and — the SV40 (1) viruses in a kernel of a cell and viruses of a variolovaccine (2) in cytoplasm of the same cell; shooters specified a nuclear envelope; x 120 000; — accumulation of adenoviruses (1) and the SV40 (2) viruses in a kernel of a cell; x 150 000; in — nucleoids of an onkovirus of type D (1) in a zone of reproduction of a virus of a variolovaccine (2) in cytoplasm; x 40 000; — nucleoid of an onkovirus of type D (it is specified by an arrow) in the developing virus of a variolovaccine — a double virus; hz00 000.

Interaction between various activators in development of S. and. can lead to their direct contact (e.g., viruses are adsorbed on a surface of nek-ry bacteria, mycoplasmas and viruses (fig. 1 and, b). Unrelated viruses at the same time get into a cell and breed or separately in a kernel and cytoplasm (fig. 2, a), or only in a kernel of a cell (fig. 2, b) or only in cytoplasm (fig. 2, c). If viruses breed in topographical proximity from each other, various forms genetic (at the level of their genomes) and not genetic (at the level of products of virus genes) interactions are observed (see. Not genetic interactions of viruses ), in particular formation of so-called double viruses (fig. 2, d), various recombinants with new properties or phenotypical the mixed virions. Similar forms gain ability to breed in cellular systems, resistant for the initial activator. At S. and. activators, interacting with each other, can significantly change the pathogenic properties. So, e.g., A. A. Smorodintsev and sotr. in 1938 established that simultaneous introduction by an animal of an influenza virus and not lethal (for monoinfection) doses of a streptococcus leads to development of the heavy generalized sepsis which is coming to an end with bystry death of experimental animals. At the same time virulence of bacteria increased. Properties of prokariot can change depending on existence of bacteriophages (prophases) in them. The bacterium of diphtheria can be a classical example, at a cut production of toxin depends on existence of a prophase in it; during the loss of a prophase the bacterium loses ability to synthesize toxin, at acquisition — recovers.

A. F. Bilibin (1970) considers that at S. and. interaction of avirulent and virulent microbes in an organism often proceeds against the background of the expressed allergization and autoimmunization that is followed by disturbance of resistance to bacterial agents.

Fig. 3. The diffraction pattern of the cell infected with viruses of vesicular stomatitis (1), a variolovaccine (2) and toksoplazmama (3); X 30 000.

The item knows the action of mycoplasmas both inhibiting, and activating on viruses at S. The activating action on viruses of nek-ry protozoa and fungi is described. E.g., at infection of culture of cells NER-2 of a toksoplazmama and viruses (fig. 3) there is a stimulation of reproduction of viruses. Thus, the following main result of interaction of two and more activators in the course of multi-infection is possible: 1) independent reproduction; 2) exaltation — strengthening of reproduction of one or all assotsiant; 3) an interference — suppression of reproduction of one or all assotsiant; 4) complementation — specific dependence of reproduction of one assotsiant on another. The phenomenon of complementation is especially eurysynusic in associations of oncogenous viruses.

Wedge, S.'s manifestations and. are peculiar since are not characterized by the sum of the symptoms specific to each of the monoinfections making them. At nek-ry S. and. change patol is not observed. process (in comparison with monoinfections), at other S. and. the antagonistic relations between activators develop (e.g., colibacillus and shigellas or salmonellas, a cholera vibrio and nek-ry colibacilli). However S. is more often and. are followed by activation patol. process (typhoid, paratyphus, tuberculosis and streptococcal or pneumococcal infection, measles and diphtheria, flu and meningococcal infection, adenoviral and staphylococcal infections, etc.).

Diagnosis Page and. it is connected with considerable difficulties and demands the combined use of all modern virologic and microbiological methods of a research (see. Bacteriological techniques , Virologic researches ).

Treatment and prevention depend on S.'s type and.

See also Infectious diseases , Infection .

Bibliography: Avakyan A. A. and Bykovsky A. F. Atlas of anatomy and ontogenesis of viruses of the person and animals, M., 1970, bibliogr.; Baroyan O. V. and Porter D. R. International and national aspects of modern epidemiology and microbiology, M., 1975; The General and private virology, under the editorship of V. M. Zhdanov and S. Ya. Gaydamovich, t. 1, M., 1982; Pogodina V. V. To a problem of virus associations, Vopr. Viru-sol., No. 1, page 8, 1977, bibliogr.; With about-lovyev V. D., Hesin Ya. E. and Bykovsky A. F. Sketches on virus cytopathology, M., 1979; Essay of l A. E., Panteleev L. G. and Myasnenko of A. M. Virusobakterialnye of association, Rostov N / D., 1978; Maug And. and. Kohler W. Mischin-fektionen, Jena, 1980.

A. F. Bykovsky.