Vertical transmission of anti-ASFV antibodies as one of potential causes of seropositive results among young wild boar population in Poland

The present study attempted to elucidate possible routes leading to the achievement of sero- positive results, among young (aged ≤1 year) wild boar population. In the years 2017-2018, the National Reference Laboratory (NRL) for African swine fever (ASF) in Poland examined nearly 27-thousand wild boar blood samples, collected during an active surveillance of ASF risk zones, for the presence of viral DNA and anti-ASFV antibodies. Out of all the examined samples, 420 were positive. However, in more than half of them (292 samples) antibodies against African swine fever virus (ASFV) were detected, while ASFV DNA was not detected in blood. Out of all 292 seropositive/PCR-negative samples, 126 belonged to young wild boars (aged ≤1 year). For this reason, the NRL in Poland has examined 10 selected seropositive wild boar carcasses to confirm or exclude post-mortem lesions for ASF as well as to investigate the presence of viral DNA in the internal organs. Neither pathological lesions for ASF nor the presence of genetic material of ASFV were found in the examined wild boars. To elucidate this outcomes, following hypotheses about possible reasons of the obtained results were drawn: the presence of convalescent animals, infection of low-virulent ASFV isolate and the vertical transmission of antibodies through the colostrum.

Virucidal effect of chosen disinfectants against African swine fever virus (ASFV) - preliminary studies

Four commercial disinfectants were chosen for being generally accepted as effective against ASFV. Only two of them, based on sodium hypochlorite and potassium peroxymonosulfate, confirmed their effectiveness in selected concentrations. Taken together, our data supports the effectivenes of chemical disinfectants containing sodium hypochlorite (1%, 0.5% in low level soiling) and potassium peroxymonosulfate (1% in high level soiling). Furthermore, these results highlight the importance of pre-cleaning steps to remove soiling before proper disinfection which improves the effectiveness of tested disinfectants.

[Experiments on new synthetic and non-absorbable surgical threads]

The aim of this work was a complex evaluation of synthetic non-absorbable surgical threads of the latest, so called 3rd generation: Novafil, Monolene and Fore-Tex. Biological tests in vivo were carried on 90 white rats of the Wistar tribe. The animals were divided into three experimental groups depending on the kind of the implanted surgical thread. Moreover, taking into account the place of implantation of the tested threads, each group was divided into two sub-groups containing 15 rats each. Operations were carried on in the conditions of surgical aseptics implanting the tested threads into the striated muscles of the back and into the liver in order to make macroscopic and microscopic tests of tissue reaction and also into the peritoneal cavity in order to carry out resistance tests after a different time of the threads stay in the tissues. The animals' sections were carried out 7, 14, 21, 90 and 180 days after the implantation of the above mentioned threads. On the basis of many year's experience of The Institute of Experimental Surgery and Biomaterial Research and review of 52 works of specialistic literature I have chosen the following additional criteria of evaluation: tests of stability of surgical knot, tests of resistance in the knot to break, tests of surgical convenience including easiness of carriage of the tested threads through the tissues, flexibility, absorbability, possibility of coiling of a loose segment of threads, electrifying and the security of the knot. Tissue reaction was based on macroscopic and microscopic tests. In macroscopic tests we paid attention to the course of healing of the threads in transversostrated muscles and in liver tissue paying attention to the behaviour of the organs of o the abdominal cavity during the section. Characteristic pictures are documented by photographs. Microscopic tests consisted on making histological samples of the threads together with the surrounding tissues. Microscopic evaluation was carried on 1080 samples using punctual of tissue reaction. The used punctual system for describing tissue reaction after implantation of non-absorbable surgical threads includes the number and degree of condensation of cells in the vicinity of the implanted thread, the width of the sphere of the inflammatory reaction and the histological analysis of the cells type. The used punctual evaluation enables objective evaluation of the tested histological samples. Variously evaluated threads Novafil, Monolene and Gore-Tex are characterised by large resistance, very good surgical convenience and minimal tissue reaction. On the basis on the carried out laboratory tests and tests on animals the following conclusions were made: 1. Non-absorbable surgical threads Novafil, Monolene, Gore-Tex do not make organism changes and heal with minimal tissue reaction what proves their high biocompatibility. 2. The used punctual evaluation of the tissues reaction after implantation of non-absorbable surgical threads allows complex and objective classification of the degree of tissues reaction. 3. Monofibrous surgical threads Novafil and Monolene do not lose resistance to break in the knot. 4. Surgical threads Novafil and Monolene are characterized by very good security of the knot while threads Gore-Tex have large flexibility and small coefficient of friction, which is the cause of weak security of the knot in case of fastening under tension. 5. Tissues reaction after implantation of synthetic non-absorbable surgical threads Novafil, Monolene and Gore-Tex is smaller in comparison with the tissues reaction which were caused by non-absorbable surgical threads tested in the former years. 6. In comparison with the non-absorbable surgical threads tested in the former years, very good surgical convenience, lack of loss of resistance to break in the knot and minimal tissues reaction give the basis to classify threads Novafil, Monolene and Gore-Tex to improved non-absorbable surgical threads of the new generation

The influence of insulin on 5-methoxytryptamine-induced wet dog shake behavior in rats

The administration of insulin intraperitoneally (2 U/kg) and intracerebroventricularly (4 U per rat) caused an increased wet dog shake response to 5-methoxytryptamine, suggesting an increase in reactivity of central serotonergic structures. Glucose, in doses which prevented hypoglycemia virtually did not change the effect of insulin.

The effect of insulin on the central serotonergic system of the rat

Single administration of insulin (1-3 U/kg) caused an increased response of rats to 5-methoxytryptamine (head shakes), 4 but not 16 h after the injection. Multiple insulin injections caused a dose and time-related increase in the number of head shakes. The effect was observed up to 24 h after the last insulin dose. Insulin (2 U/kg given for 3-14 days) caused an increase in the cerebral concentration of 5-hydroxyindoleacetic acid (5-HIAA) and accelerated the cerebral serotonin (5-HT) turnover. The 5-HIAA concentration was approx. twice as high as in the controls, regardless of the duration of the treatment; the degree of 5-HT turnover acceleration did not depend on the duration of the treatment, either, and was observed up to 14 days after cessation of insulin administration.

Effects of histamine and H1 and H2-receptor antagonists on wet-dog-shake episodes in rats induced with tranylcypromine and 5-methoxytryptamine

Intraperitoneally administered tranylcypromine and 5-methoxytryptamine induced in rats the so called wet-dogs-shake behaviour. Histamine injected intraventricularly had no effect on the number or episodes of this behaviour during the first 40 minutes of observation. On the other hand, dimaprit in doses of 5 micrograms/rat injected also intraventricularly increased the number of these episodes. Thenalidine and antazoline--antagonists of the H1-receptor, and cimetidine and ranitidine--antagonists of the H2-receptor, decreased the number of these episodes proportionally to the injected dose. Similar effects were obtained after cimetidine injection into the lateral ventricle. In the light of these observations it may be supposed that these antihistaminic agents exert an inhibitory effect not only on the histaminergic system but decrease indirectly also the activity of the serotoninergic system.

The influence of insulin hypoglycemia on central dopaminergic structures of the rat

Daily administration of insulin, 2 U/kg/day for 9 days, leads to a marked increase in the activity of central dopaminergic structures, reflected by an increase in the apomorphine or amphetamine-induced stereotypy and a decrease in fluphenazine-induced catalepsy. These changes are accompanied by a depression of cerebral dopamine and noradrenaline levels and a depression of noradrenaline utilization in the brain.