Molecular evidence of Babesia caballi (Nuttall and Strickland, 1910) parasite transmission from experimentally-infected SCID mice to the ixodid tick, Haemaphysalis longicornis (Neuman, 1901).

Molecular evidence that suggests the possible role of the ixodid tick, Haemaphysalis longicornis and its eggs in the transmission of equine Babesia caballi parasites is presented herein. Using polymerase chain reaction (PCR) to assay for DNA in parasites, presumably acquired by ticks that were allowed to feed on splenectomized-SCID mice, experimentally exposed to in vitro-cultivated B. caballi, we have obtained positive bands that corresponded to the expected B. caballi-specific 430bp gene fragment in 50% of female ticks used, and in 75 and 25% of eggs and larval progeny, respectively. Also, parasite DNA was detected in ticks, eggs and larvae as late as the 16th to the 20th day post-host infestation. Present findings support to the potential role of H. longicornis in the transmission of B. caballi parasites. Its capability, however, to successfully transmit the infection to horses under natural conditions in the field needs to be further ascertained. To our knowledge, this is the first documented study incriminating H. longicornis as a most and likely biological vector of equine babesias.     

Causes of anaphylactoid reactions in cattle after administration of lipoid preparations]

In 1986-1988, adverse anaphylactoid reactions (AR) were observed in animals in Czechoslovakia after the administration of oil adjuvant-containing vaccines or other lipoid drugs. Treated animals showed signs resembling the classic anaphylactic reaction, i.e. restlessness, salivation, pruritus, oedema and cyanosis of udder and vulva, and eyelid oedema, developing within a few minutes. The reactions were not elicited by the antigen alone, but by the oil adjuvant. The aim of our experiments was to identify substances eliciting the reaction in susceptible animals and to investigate possible induction mechanisms. The emulsifier Tween 80 has been demonstrated to be an AR inducing component of vaccines and drugs (Tab. I and III). Weak or moderate reactions were observed in 33% of animals treated with 5% Tween and 66% of those treated with 10% Tween showed strong reactions. On the other hand, no reactions were elicited by treatment with several paraffin oils of different quality (Tab. I) nor with an oil-in-water emulsion containing Montanid as an emulsifier (Tab. II). The role of the vegetative nervous system in the rise of AR has been confirmed. AR were suppressed in animals pretreated with parasympatholytic atropine and enhanced in a part of those pretreated with parasympathomimetic pilocarpine (Tab. III). The percentage of animals affected and the intensity of AR were also lower in animals pretreated with complement inhibitor epsilon-aminocapronic acid (Tab. IV). A major role of complement activation is suggested in the discussion of possible mechanisms of AR induction. It is possible to draw a conclusion on the basis of the results presented here and of the analysis of individual cases that a certain degree of animal susceptibility, depending on the phase of reproductive cycle, metabolism level and neurovegetative balance is necessary besides the administration of an AR inducer (Tween 80 in our case). Hence it seems that the adverse anaphylactoid reactions results from interactions of the two factors, i.e. administration of an AR inducer to susceptible animals.     

Pharmacokinetics of norfloxacin and its N-desethyl- and oxo-metabolites in broiler chickens.

Norfloxacin was given to 2 groups of chickens (8 chickens/group) at a dosage of 8 mg/kg of body weight, IV and orally. For 24 hours, plasma concentration was monitored serially after each administration. Another group of chickens (n = 30) was given 8 mg of norfloxacin/kg orally every 24 hours for 4 days, and plasma and tissue concentrations of norfloxacin and its major metabolites desethylenenorfloxacin and oxonorfloxacin were determined serially after the last administration of the drug. Plasma and tissue concentrations of norfloxacin, desethylenenorfloxacin, and oxonorfloxacin were measured by use of high-performance liquid chromatography. Pharmacokinetic variables were calculated, using a 2-compartment open model. For norfloxacin, the elimination half-life (t1/2 beta) and the mean +/- SEM residence time for plasma were 12.8 +/- 0.59 and 15.05 +/- 0.81 hours, respectively, after oral administration and 8.0 +/- 0.3 and 8.71 +/- 0.23 hours, respectively, after IV administration. After single oral administration, norfloxacin was absorbed rapidly, with Tmax of 0.22 +/- 0.02 hour. Maximal plasma concentration was 2.89 +/- 0.20 microgram/ml. Oral bioavailability of norfloxacin was found to be 57.0 +/- 2.4%. In chickens, norfloxacin was mainly converted to desethylenenorfloxacin and oxonorfloxacin. Norfloxacin parent drug and its 2 major metabolites were widely distributed in tissues. Considerable tissue concentrations of norfloxacin, desethylenenorfloxacin, and oxonorfloxacin were found when norfloxacin was administered orally (8 mg/kg on 4 successive days). The concentration of the parent fluoroquinolone in fat, kidneys, and liver was 0.05 micrograms/g on day 12 after the end of dosing.     

Diagnosis of avian encephalomyelitis

The diagnostic value of laboratory examination methods was assessed in the diagnosis of avian encephalomyelitis in seven to twenty-two days old chickens. Histological examination and immunofluorescent test are expedient methods meeting the requirements for timely application of infection-control measures. The agreement of histological examination with the over-all laboratory examination is 70 to 81% and the agreement of the immunofluorescence test is 76%. Bioassay on chickens followed by a histological examination appears to be the best method, providing results with the highest significance. However, it is lengthy, applicable to the necessary demonstration of a virus or to cases when the histological or immunofluorescence examinations are dubious. With the over-all laboratory evaluation the method shows agreement in 95 to 100% of cases. The diagnostic value of the method of virus isolation in chick embryos is reduced by the fact that intercurrent viruses (adenoviruses, IB and others) may be passaged at the same time.     

Changes in the hypothalamus in continuously irradiated sheep

Neurosecretion, PAS-positive mucopolysaccharides and the Nissl substance were studied in the neurons of the rostral, medial and caudal hypothalamus of continuously irradiated ewes. The study was performed on 21 ewes of the Slovak Merino breed at the live weight of 34 kg. The animals were in the period of physiological anoestrus and their age was two to three years. The first group of six ewes was the control. The second group included 15 sheep irradiated with a total dose of 6.7 Gy (700 R) for seven days. Co60 was used as the source of irradiation. The animals of this group were killed seven days from treatment. The ewes in the third group were left for the study of mortality. The brains were perfused with 2% buffered paraformaldehyde immediately after the bleeding of the sheep; then the brains were removed from skulls and fixed in buffered picroformol. Paraffin slices were stained with haematoxylin-eosine, aldehyde-fuchsine and alcian blue for neurosecretion, with PAS-reaction for mucopolysaccharides and with cresyl violet for the Nissl substance. As found, the irradiation of the whole body inhibits the activity of neurosecretory cells in rostral and medial hypothalamus, thus reducing neurosecretion. These regions also show a reduced activity of PAS reaction used for the demonstration of mucopolysaccharides. The observed changes also included damage of the endothelium of blood vessels with the occurrence of erythrocyte extravasates and with haemorrhages.(ABSTRACT TRUNCATED AT 250 WORDS)     

Histochemical and morphometric studies of the cranial tibial muscle in dogs of different dynamic aptitudes (greyhound, German shepherd and fox terrier)

A histochemical and morphometric study of the cranial tibial muscle of the greyhound, the German shephard and the fox terrier was carried out using hematoxyline-eosin, PAS, Gomori trichrome, SDH, LDH, NADH-tr and ATPase staining (with pH adjustments to both acidic and basic levels), with the goal of comparing the proportion and distribution of type I and type II fibers within the muscle. Significant differences were found between the three breeds of dogs. It is suggested that these differences are related to the locomotor activities of the three breeds.     

Spatial patterns of fire occurrence in Catalonia,NE, Spain

In this paper, we analyse spatial patterns of fire occurrence in Catalonia (NE Spain) during 1975–98. Fire scar maps, discriminated by means of 30–60 m resolution remote sensing imagery, have been used as a source of fire occurrence. We employ several visual or analytical approaches to interpret fire occurrence in this region, such as those of Minnich and Chou (1997), Ricotta et al. (2001) or Krummel et al. (1987). Crucial spatial patterns such as fire size distribution, fire frequency distribution, spots and residual vegetation islands are documented. In addition, several geographical layers were overlaid with burned area maps in order to determine interactions between fire occurrence and environmental parameters such as altitude, slope, solar radiation, and burned land cover. Assuming that fire occurrence is well determined by such a posteriori empirical factors we detect areas most prone to fire in this region and aim to enhance the local forest management and conservation plans.     

Bird assemblages in forest fragments within Mediterranean mosaics created by wild fires

The role of habitat heterogeneity as a key factor in determining species pools in habitat mosaics has been acknowledged, but we still know little on the relative importance of the different ecological processes acting within such complex landscapes. We compared species richness and distribution in forest fragments imbedded in shrub-lands to those in continuous forests or in continuous shrublands. We examined the consistency of our data with the predictions of two hypotheses: 1) the Habitat fragmentation hypothesis which states that fragmentation has negative effects on the species from the original continuous habitat; 2) the Habitat supplementation /complementation hypothesis which stipulates that the presence of a matrix habitat around the fragments will mitigate negative effects on the species from the original habitat (supplementation) or allow the presence of species that depend on the presence of both the fragment and matrix habitats (complementation). We show that: 1) species richness in forest fragments did not differ from species richness in segments of continuous forests of equal area; 2) the bird community of forest fragments got impoverished in some forest species but a higher proportion of species common in continuous forests were not affected by fragmentation; 3) fragment communities had a significant proportion of common species that were scarce in, or absent from both continuous forests and shrublands. While, a few forest species supported predictions from the fragmentation hypothesis, occurrence patterns observed in several other species were consistent with either the supplementation or the complementation hypotheses. Our results suggest that there is no single hypothesis that properly captures the consequences of a shift from continuous forests to a mosaic of forest fragments and shrublands and that different ecological mechanisms act in conjunction to determine species pools in habitat mosaics. Habitat heterogeneity at a local scale appears a key factor in maintaining bird diversity in fire driven Mediterranean landscapes.