Occurrence of enteric redmouth disease in rainbow trout (Oncorhynchus mykiss) on farms in Croatia

During the spring of 1996 and autumn of 1997 unusual mortality outbreaks among rainbow trout fry and yearlings occurred at two different trout farms, resulting in mortality of 20 and 10 per cent, respectively. Generally, the affected fish, swimming at the water surface, were reluctant to eat and were dark pigmented with visible haemorrhages around and within the oral cavity. Bacterial isolates from moribund fish from both cases were identified as Yersinia ruckeri by standard biochemical tests and API 20E. The isolated strains were found to be sensitive to tetracycline, chloramphenicol, co-trimoxazole, nalidixic acid, flumequine, enrofloxacin, carbenicillin and gentamicin. Microplate agglutination assay confirmed that both isolates belonged to serotype O1. The pathogenicity of the isolated bacteria was confirmed by challenge experiment. Titres of specific antibodies were determined in the sera of survivors. The titre was highest on the 21st day postchallenge and was detectable until the 81st day.     

Serological Evidence for Borrelia burgdorferi Infection Associated with Clinical Signs in Dairy Cattle in Slovakia

In the course of epizootological research on Lyme borreliosis in domestic and farm animals, the serological evidence for the occurrence of this zoonosis in cattle was screened. An ELISA showed that 25.2% of cattle from seven geographical areas in Slovakia were positive for anti-Borrelia IgG antibodies. In particular localities, the seroprevalence ranged from 0.6% to 34.3%. Of 33 cases with clinical signs, 20 ELISA-positive samples were also confirmed in Western blots. The most frequent clinical signs were lameness and swollen joints, but most of the cases were asymptomatic. The occurrence of Borrelia burgdorferi antibodies and suspected clinical signs in cattle of Slovak regions indicates that veterinarians should pay attention to this disease in their clinical practice and include it within the differential diagnosis.     

A survey of chickens for viable toxoplasms in Croatia

Brain tissues of 716 slaughtered domestic chickens (524 broilers and 192 hens) were bioassayed for viable toxoplasms. Each tissue was homogenized and subcutaneously injected into 4 SPF mice. Six weeks later the mice were euthanatized and their brains microscopically examined for Toxoplasma gondii tissue cysts. Three (0.4%) out of a total of 716 birds were positive. All positive cases were hens. This is the first isolation of T. gondii from chickens in Croatia.     

The in vitro motility response to various anthelmintics of third-stage larvae of Oesophagostomum spp. from pigs

The in vitro activities of thiabendazole, levamisole, pyrantel, morantel and ivermectin against Oesophagostomum spp., the nodular worm of pigs, were determined and compared. The study was carried out using isolates of O. dentatum and O. quadrispinulatum, which had been defined in vivo. Infective larvae were exposed to the anthelmintics for 24 h and then placed in a micromotility meter. All the treatments significantly reduced the motility of the ensheathed L₃ larvae, but the micromotility meter was not able to differentiate between anthelmintic resistant and anthelmintic susceptible isolates.     

On the fracture morphology in wood

Summary Structural changes in spruce and aspen wood samples subjected to axial compression were examined by means of the scanning electron microscope. For comparison, macroscopic model experiments were carried out on tube-shaped samples made of paper so as to represent segments of fibriform xylem cells. The results show that there are fracture patterns characteristic of wood in general and others characteristic of the species of wood. The phenomena characteristic of wood in general are prevalent at the cellular level and in the fracture behaviour of the cell wall layers and perforations. The characteristics of the various species of wood dominate at the level of the growth rings and are decisively influenced by the composition and arrangement of the tissues. The model experiments show that the failure morphology of the individual cells of the xylem may be explained to some extent by their geometry.     

Distribution of Aeolothrips intermedius Bagnall (Thysanoptera: Aeolothripidae) and its potential prey Thysanoptera species on different cultivated host plants

The results of the monitoring of Thysanoptera species on cultivated plants in Slovenia (2000–2001), Croatia (1994–1996), and Serbia and Montenegro (1988–2003) are presented in this study. The aim of the investigation was to study the host plant distribution of the predator Aeolothrips intermedius Bagnall and its potential prey. Banded thrips were found on 30 different host plant species belonging to 16 botanical families, always in mixed populations with phytophagous or facultative phytophagous insects (including 18 Thysanoptera species). On the vegetative parts of the cultivated plants, banded thrips were found less numerous in spite of the massive population of some harmful thrips species. This indicates highly important role of pollen as alternative food for Aeolothrips intermedius.