There is an increasing need for rapid and easily interpreted in vitro assays to screen for possible cytotoxicity of pesticides. The objective of this study was to investigate the effect of the carbamate insecticide bendiocarb on mammalian and insect cell cultures. The cytotoxicity of this insecticide was evaluated by cell proliferation and cellular damage was assessed by evaluation of the cytopathic effect and lactate dehydrogenase (LDH) leakage. Cells of insect origin (Sf21) were the most sensitive to bendiocarb with significant (P < 0.01) suppression of their proliferative activity ranging from 10(-1)-10(-5) M. However, significant suppression of proliferative activity was also recorded in rat liver cells (WBF344; 10(-1)-10(-3) M; P < 0.01-0.05) and rabbit kidney cells (RK13; 10(-1) M; P < 0.01). In contrast with the proliferation activity of cells, a cytopathic effect based on cellular damage and LDH leakage into the medium was observed only at the highest concentration (10(-1) M) in RK 13 and WBF344 cells, but not in the Sf21 insect cell line. Our results indicate that bendiocarb exposure caused a cell-type dependent decrease in cell proliferation; however, cell damage and LDH leakage into the medium were not present or were strongly limited, dependent on the cell phenotype. Cell proliferation was shown as a sensitive indicator for evaluation of the cytotoxic effect of bendiocarb in vitro; on the other hand, microscopic signs of cellular damage and LDH leakage were insufficient in vitro markers.

The prevalence of porcine circovirus 2 (PCV-2) infection in the pig population in Slovakia was investigated. Sera from pigs suspected for post-weaning multisystemic wasting syndrome (PMWS) as well as clinically healthy pigs were tested for viral DNA and specific IgM and IgG antibodies. Pigs (n = 198) were categorized to weaning, grower and fattening ones and sows. The results showed that PCV-2 antibodies were present in 53.4% of PMWS-suspects, in 50.0% of healthy pigs and in 69.0% of sows. In PMWS-suspect grower pigs, 40.7% were positive for IgM+IgG antibodies and 22.2% for viral DNA. In PMWS-suspect fattening pigs, 50.0% were positive for IgM+IgG antibodies and 25.0% for viral DNA. In healthy fattening pigs, almost 90.0% were positive for IgG antibodies and 38.5% for viral DNA. The highest proportion of PMWS-suspects was in grower pigs and specific antibodies were increasing with the age of pigs. A combination of positivities for IgG+IgM antibodies and viral DNA was a highly significant marker of PMWS. Viral DNA was detected in seropositive as well as seronegative PMWS-suspects. Overall, in all categories of pigs tested, specific antibodies and viral DNA were detected in 54.0% and 35.5%, respectively.

Porcine circovirus 2 (PCV-2) is a primary agent of post-weaning multi-systemic wasting syndrome (PMWS), ubiquitous in pig herds. The course of viraemia and seroconversion in naturally infected pigs were investigated in piglets from the 2nd week of their life. Piglets were divided into seropositive (Ab(+)) and seronegative (Ab(-)) groups. Subsequently, after vaccination against PCV-2 (Ingelvac(®) CIRCOFLEX™, Böehringer Ingelheim), they were further divided into non-vaccinated seronegative (NVAC/Ab(-)) and seropositive (NVAC/Ab(+)), and vaccinated seronegative (VAC/Ab(-)) and seropositive (VAC/Ab(+)). PCV-2 colostral antibodies failed to prevent development of natural PCV-2 infection in conventional piglets; however, this occurred at a higher age in comparison with seronegative pigs. Neither colostral nor post-infection antibodies prevented development of viraemia, which persisted up to the end of the study (the 19th week), but without clinical signs of PMWS. Vaccination failed to prevent development of natural PCV-2 infection, but viraemia was limited to between the 8th and 10th week. The presence of colostral anti-PCV-2 antibodies did not show any untoward effect to vaccination; on the contrary, VAC/Ab(+) animals showed the lowest titre of viraemia.

SummarySPF male Wistar rats were exposed for four months to lead acetate trihydrate present in drinking water (100 mg/l) and subsequently infested with 1000 ± 100 infective A. suum eggs. Metabolic activity of phagocytes and proliferative activity of T-lymphocytes were investigated on Day 4 and 8 after A. suum eggs infestation (Day 130 and 134 of lead acetate trihydrate exposition). The results demonstrated that treatment with lead acetate trihydrate led to increased susceptibility to infestation, manifested by increased average number of A. suum larvae in the lungs of exposed rats compared to unexposed ones. Moreover, migration of A. suum larvae on Day 8 was associated with significant increase in index of metabolic activity of phagocytes in unexposed rats in comparison with controls. In contrast, in rats exposed to the lead and infested by A. suum eggs a non-significant increase in the studied immunological parameters was recorded. Significant differences in immunological parameters were observed between unexposed, infested and infested and exposed groups of rats. In the unexposed group of animals Ascaris suum infestation caused a significant increase in the index of metabolic activity of phagocytes and stimulation index of lymphocytes in comparison with lead exposed rats.

Keywords: Bovine viral diarrhea virus 1 and 2; cell line susceptibility; virus recovery or by mutants of cp BVDV derived from non-cp BVDV in persistently infected animals. Although many rapid and less laborious diagnostic techniques are used to detect BVDV, up till now the virus isolation is considered as a gold standard. Besides other factors, the success rate of virus isolation depends on the susceptibility of cell line used to detect and isolate the virus.Thus, the aim of this study was to compare the susceptibility of different cell lines derived from various tissues to non-cp and cp strains of BVDV. In our experiments we examined four cell lines derived from various bovine tissues and one cell line derived from sheep fetal thymus cells for the inoculation with BVDV strains. Bovine embryonic lungs (BEL), bovine turbinated (BT), Madin-Darby bovine kidney (MDBK), calf oesopharyngeal (KOP-R), and sheep fetal thymus (SFT-R) cell lines were obtained from the Veterinary Faculty, Munich, Germany. All cell cultures were BVDV-free. Cell cultures were grown in Eagle's MEM (Gibco) supplemented with 7% fetal calf serum (Biochrom), penicillin 100 IU/ml, streptomycin 100 µg/ml (Gibco), and 1% non-essential amino acids (Biochrom). The cells were maintained at 37°C in a humidified 5% CO 2 atmosphere.Cell lines were inoculated with two cp BVDV strains (NADL and Oregon C24V) and two non-cp BVDV strains (PT810 and CS8644) obtained from the Veterinary Faculty, Munich, Germany. Three viral strains tested (NADL, Oregon C24V, PT810) were BVDV-1, whereas fourth strain (CS844) was BVDV-2. Each cell culture was inoculated with 50 µl of viral suspension (10 4.0 TCID 50 /ml per 25 cm 2 of confluent * Corresponding author. E-mail: pistl@uvm.sk; fax: +421-552981011. Abbreviations: BEL = bovine embryonic lungs; BVDV-1 and 2 = Bovine viral diarrhea virus 1 and 2; BT = bovine turbinated; cp = cytopathic; KOP-R = calf oesopharyngeal; MDBK = Madin-Darby bovine kidney; ML = mink lungs; non-cp = non-cytopathic; SFT-R = sheep foetal thymus Bovine viral diarrhea virus 1 and 2 (BVDV 1 and 2) (the genus Pestivirus, the family Flaviviridae) is distributed worldwide and causes severe economical losses due to the decreased fertility, abortions, diarrhea, respiratory symptoms, and persistent infection in intrauterinary infected calves. So far, two species BVDV-1 and BVDV-2 are known to infect cattle (1). Most of the BVDV isolates appear to be BVDV-1 genotype that comprises 12 different genetic groups (2). Strains of BVDV-2 genotype were initially recognized by their higher virulence, but the isolates of lower virulence have also been assigned to this genotype (3). According to the cultivation characteristics and pathogenic properties of BVDV-1, 2 we differentiate between cytopathic (cp) and non-cytopathic (non-cp) BVDV strains (4). Non-cp BVDV strains are capable of producing persistent infection and consequently, this is the reason why most of the field isolates are of the non-cp type. Persistently infected animals are life-long virus shedders and are...