Study of the immunological activity of blood in various rickettsial and viral infections]

The content of various types of antibodies were studied in the blood serum of laboratory animals in experimental tick-borne rickettsiosis of Northern Asia. This was done by a simultaneous staging of indirect hemagglutination, indirect hemolysis, compliment fixation under cold conditions, and agglutination with Proteus antigen OX19 tests. Immune horse sera to the influenza virus were also studied with the aid of several serological tests. The data obtained pointed to the significant differences in the properties of individual types of antibodies. Immunological activity of the sera under study depended on the correlation in them of various types of antibodies at various periods of the infectious process in combination with the influence upon the immunogenesis of the individual and species immunological reactivity.     

Ticks on reptiles and amphibians in Central Amazonia,with notes on rickettsial infections

Reptiles and amphibians are exceptional hosts for different ectoparasites, including mites and ticks. In this study, we investigated tick infestations on reptiles and amphibians trapped in Central Amazonia, and also assessed the presence of rickettsial infections in the collected ticks. From September 2016 to September 2019, 385 reptiles (350 lizards, 20 snakes, 12 tortoises, and three caimans) and 120 amphibians (119 anurans and one caecilian) were captured and examined for ectoparasites. Overall, 35 (10%) lizards, three (25%) tortoises and one (0.8%) toad were parasitized by ticks (124 larvae, 32 nymphs, and 22 adults). In lizards, tick infestation varied significantly according to landscape category and age group. Based on combined morphological and molecular analyses, these ticks were identified as Amblyomma humerale (14 larvae, 12 nymphs, 19 males, and one female), Amblyomma nodosum (three larvae, one nymph, and one female), and Amblyomma rotundatum (four larvae, three nymphs, and one female), and Amblyomma spp. (103 larvae and 16 nymphs). Our study presents the first records of A. nodosum in the Amazonas state and suggests that teiid lizards are important hosts for larvae and nymphs of A. humerale in Central Amazonia. Moreover, a nymph of A. humerale collected from a common tegu (Tupinambis teguixin) was found positive for Rickettsia amblyommatis, which agrees with previous reports, suggesting that the A. humerale-R. amblyommatis relationship may be more common than currently recognized.

     

The effect of antibiotics and immunostimulants on rickettsial persistence in experimental typhus infection

A model of experimental typhus infection has shown that not only specific protection factors but also nonspecific ones are very important to remove Rickettsia prowazekii from macroorganisms. A complex application of antibiotics and drugs increasing immunobiological reactivity of the organism (prodigiosan, methyl uracil) noticeably decreases the rickettsia persistence level in the organism of experimental animals, the indices of specific and nonspecific protection being increased.