From Big Medical Encyclopedia

TRANSOVARIAL TRANSFER of the activator of infek-c and and (Latin trans through + ovarium an ovary) — ability of females of blood-sicking arthropods — carriers of causative agents of diseases of the person and animals to transfer the received activators to posterity, i.e. to lay the infected eggs, from to-rykh then there are infected larvae.

The phenomenon Other is closely connected with the transmissible mechanism of transmission of infection (see Mechanisms of transmission of infection). It is caused by features of a life cycle of arthropods (see) and promotes increase in number of the infected individuals of carriers even in cases of lack of a meeting of larvae with infected zhi-votnym-prokormitelem.

The mechanism actually Etc. has the following sequence: the activator breeding in an organism of a specific carrier is brought by current of a hemolymph in various bodies and fabrics where can collect (e.g., in salivary and gonads); from gonads of females it gets into the forming ova. Yu. S. Balashov and A. B. Dayter (1973) established that for successful Other rickettsiae a certain level of their concentration in a hemolymph at the time of formation of chorion of oocytes is necessary. Rzhegachek (J. Rehacek, 1963) noted need of rather high concentration of a virus for overcoming a so-called egg barrier.

The phenomenon Other is better studied at mites. So, ixodic mites (see) are capable to Other causative agents of tick-borne encephalitis and nek-ry other arbovirus, rickettsiae, a number of bacteria; argasovy mites (see) — to Other rickettsiae, spirochetes and probably a nek-ry arbovirus; din-zoidnye mites (see) — to Other nek-ry viruses, rickettsiae, bacteria; mites-krasnotelki (see Kras-notelkovy mites) — to Other rickettsiae (activators of a tsutsugamusha). It speaks morfofiziol. features of mites; the haemo purpose at them separates from egg only one cover, except egg while at mosquitoes of such covers three. Besides, ticks can receive the activator at a krovososaniye at a stage of a larva and keep it at a molt (see. Transphase transfer), i.e. by the time of formation of gonads it is already present at an organism. Insects carriers eat blood in an adult stage therefore the activator gets to an adult organism with already created gonads. Data about Other insects concern hl. obr. arboviral infections. It is proved by Other mosquitoes of causative agents of encephalitis of the Western Neil, fever of the Dengue (see the Dengue), etc. Sh. D. Moszkowski (1937) and Item A. Petrishcheva (1939) established infection of volunteers with flebotomny fever (see) from the mosquitoes which were not eating before brought in laboratory out of layings of the infected females.

Ability to Other a specific arbovirus is confirmed at mosquitoes by means of the newest methods of a research. Not all infected females of the same type of arthropods are capable to transfer the activator to posterity. Experiences with the ixodic mites infected with rickettsiae showed what in 16 — 37% of cases Other does not occur (the laying of eggs and larvae which left it were infected not completely).

See also Carriers.

Bibliography: Balashov Yu. Page and D and y-t e r A. B. Blood-sicking arthropods and rickettsiae, JI., 1973; Biological relationship of blood-sicking arthropods with causative agents of diseases of the person, under the editorship of P. A. Petrishcheva, M., 1967;

Barge haulers S. A. and Pautovv.N. Mosquitoes and mites — carriers of causative agents of viral and rickettsial diseases of the person, M., 1975; Nau

of m of P. JI., at t about in and V. P. and Chu N and x and S. P N. Ixodic mites and causative agent of tick-borne encephalitis, Medical pas-razitol., t. 60, No. 1, page 58, 1981.

G. A. Sidorova.