František Treml

Ecological conditions of natural foci of tularaemia in the Czech Republic

Tularaemia, a zoonosis of veterinary and public health importance, commonly occurs in the Czech Republic as well as other countries of Northern Hemisphere. The objective of this study was to analyse the environmental conditions of distribution of natural foci of tularaemia and their long-term persistence in the Czech Republic. A geographic information system has been used for this purpose. A new variable (xt), the mean number of natural foci in a specific area, has been suggested for the evaluation of diseases occurring in natural foci. Comparing two 15-year periods, a close correlation between the geographic distribution and numbers of natural foci of tularaemia in the Czech Republic in 1971–1985 and 1986–2000 (r = 0.91, n = 1814, t = 92.50, p = 0.01) was found. Natural foci of tularaemia have been persistent, but not stationary, over the period of 30 years and the geographic area of their occurrence has not been considerably growing or diminishing in the Czech Republic. The highest numbers of natural foci of tularaemia were in habitats of alluvial forests (xt = 7.20), geographic areas of up to 200 m of elevation above sea (xt = 9.18), 8.1–10.0 °C of mean annual air temperature (xt = 6.24), 450–700 mm of mean annual precipitation (xt = 2.84), and 2001–2200 hour of mean annual sunshine duration (xt = 8.77). It was proved that tularaemia persists in specific areas of natural foci, the general environmental conditions of which can be defined and make it possible to predict the occurrence of tularaemia in other areas of suitable conditions.

Tularemia induces different biochemical responses in BALB/c mice and common voles

BackgroundBoth BALB/c mice and common voles (Microtus arvalis) are considered highly susceptible to tularemia. However, the common vole is reported to harbour Francisella tularensis in European habitats as well as to survive longer with chronic shedding of the bacterium. The purpose of the present study was to compare the response of these two rodents to a wild Francisella tularensis subsp. holarctica strain infection.MethodsRodents were evaluated for differences in the total antioxidant capacity derived from low-molecular-weight antioxidants, biochemistry including lipid metabolism, tissue bacterial burdens and histopathology following experimental intraperitoneal infection with 160 colony forming units (CFU) pro toto.ResultsBacterial burdens in common voles started to develop later post-exposure and amounted to lower levels than in BALB/c mice. Elevation of liver function enzymes was more pronounced in mice than common voles and there were marked differences in lipid metabolism in the course of tularemia in these two species. Hypertriglyceridemia and hypercholesterolemia developed in mice, while physiologically higher levels of triglycerides and cholesterol showed a decreasing tendency in common voles.On the other hand, the total plasma antioxidant capacity gradually dropped to 81.5% in mice on day 5 post-infection, while it increased to 130% on day 6 post-infection in common voles. Significant correlations between tissue bacterial burdens and several biochemical parameters were found.ConclusionAs differences in lipid metabolism and the total antioxidant capacity of highly susceptible rodent species were demonstrated, the role of triglycerides, cholesterol and antioxidants in tularemic sepsis should be further investigated.

Piezoelectric Biosensor for a Simple Serological Diagnosis of Tularemia in Infected European Brown Hares (Lepus europaeus)

Piezoelectric biosensor was used for diagnosis of infection by Francisella tularensis subsp. holarctica in European brown hares. Two kinds of experiments were performed in this study. First, sera from experimentally infected European brown hares (Lepus europaeus) were assayed by piezoelectric biosensor and the seventh day post infection was found as the first one when statistically significant diagnosis of tularemia was possible; all other sera collected from hares later than on day 7 following the infection were found tularemia positive. Typing to classify the field strain of F. tularensis used for the experimental infection was confirmed by proteome study. Second, sera from 35 European brown hare specimens sampled at hunting grounds and tested as tularemia positive by slow agglutination allowed diagnosis of tularemia by the piezoelectric biosensor. All these sera of naturally infected hares were found as tularemia positive, too. Efficacy of the piezoelectric biosensor for the serological diagnosis of tularemia is discussed.

Lead toxicosis of captive vultures: case description and responses to chelation therapy

BackgroundLead, a serious threat for raptors, can hamper the success of their conservation. This study reports on experience with accidental lead intoxication and responses to chelation therapy in captive Cinereous (Aegypius monachus) and Egyptian (Neophron percnopterus) Vultures.ResultsSoil contamination by lead-based paint sanded off the steel aviary resulted in poisoning of eight Cinereous and two Egyptian Vultures. A male Egyptian Vulture developed signs of apathy, polydipsia, polyuria, regurgitation, and stupor, and died on the next day. Liver, kidney and blood lead concentrations were 12.2, 8.16 and 2.66 μg/g, respectively. Laboratory analyses confirmed severe liver and kidney damage and anaemia. Blood Pb levels of Pb-exposed Cinereous Vultures were 1.571 ± 0.510 μg/g shortly after intoxication, decreased to 0.530 ± 0.165 μg/g without any therapy in a month and to 0.254 ± 0.097 μg/g one month after CaNa2EDTA administration. Eight months later, blood lead levels decreased to close to the background of the control group. Blood parameters of healthy Pb-non-exposed Cinereous Vultures were compared with those of the exposed group prior to and after chelation therapy. Iron levels in the lead-exposed pre-treatment birds significantly decreased after chelation. Haematocrit levels in Pb-exposed birds were significantly lower than those of the controls and improved one month after chelation. Creatine kinase was higher in pre-treatment birds than in the controls but normalised after therapy. Alkaline phosphatase increased after chelation. A marked increase in the level of lipid peroxidation measured as thiobarbituric acid reactive species was demonstrated in birds both prior to and after chelation. The ferric reducing antioxidant power was significantly lower in pre-treatment vultures and returned to normal following chelation therapy. Blood metallothionein levels in lead-exposed birds were higher than in controls. Reduced glutathione dropped after CaNa2EDTA therapy, while oxidised glutathione was significantly lower in both pre- and post-treatment birds. A chick in an egg produced by a Cinereous Vulture female two months after lead toxicosis died on day 40 of artificial incubation. Lead concentrations in foetal tissues were consistent with levels causing avian mortality.ConclusionsThe reported blood parameters and reproduction impairment in captive birds may have implications for professionals dealing with lead exposure in wild birds.

Mycoplasma gallisepticum infection in the grey partridge Perdix perdix: outbreak description, histopathology, biochemistry and antioxidant parameters

BackgroundThe grey partridge is an important game bird in Europe that has declined considerably over the last decades. The production and release of farm-bred birds can be threatened by infectious agents. The objective of this study was to describe the outbreak, pathology, and blood and tissue biochemical responses in a flock of grey partridges naturally infected with Mycoplasma gallisepticum.ResultsMorbidity and mortality rates were 100% and 60%, respectively. Necropsy revealed an accumulation of caseous exudate within the infraorbital sinuses, tracheitis, pneumonia and airsacculitis. There were significant increases in activities of lactate dehydrogenase, creatine kinase and amylase, and levels of total protein and glucose in Mycoplasma-infected birds when compared to control. Catalase showed significantly lower activity in the heart, lungs, liver and gonads of Mycoplasma-infected birds. Glutathione-S-transferase activity was elevated in the eye and the associated infraorbital sinus and kidneys, and decreased in the liver. Decreased levels of reduced glutathione were found in the heart, kidneys, liver and gonads. The activity of glutathione reductase was lower only in the lungs. Compared to healthy birds, mycoplasmosis in the grey partridge caused significant differences in the level of lipid peroxidation in lungs and plasma (p < 0.05), while the ferric reducing antioxidant power was lower in the heart and kidneys (p < 0.01). Significant correlations among responses of the antioxidant parameters were found namely in the heart, lungs, spleen, liver and plasma. There were also numerous significant inter-tissue correlations of all the studied antioxidant parameters.ConclusionsThe present study demonstrates the high susceptibility of grey partridges to natural infection by M. gallisepticum, the severity of the disease based on histopathology, and the modulation of blood chemical profiles and oxidative stress-associated parameters in the avian hosts, thus enhancing the understanding of the pathogenesis of mycoplasmosis in birds. Moreover, the reported reference values can be useful for the evaluation of the state of health in grey partridges.

Biochemical responses and oxidative stress in Francisella tularensis infection: a European brown hare model

BackgroundThe aim of the present study was to investigate biochemical and oxidative stress responses to experimental F. tularensis infection in European brown hares, an important source of human tularemia infections.MethodsFor these purposes we compared the development of an array of biochemical parameters measured in blood plasma using standard procedures of dry chemistry as well as electrochemical devices following a subcutaneous infection with a wild Francisella tularensis subsp. holarctica strain (a single dose of 2.6 × 109 CFU pro toto).ResultsSubcutaneous inoculation of a single dose with 2.6 × 109 colony forming units of a wild F. tularensis strain pro toto resulted in the death of two out of five hares. Plasma chemistry profiles were examined on days 2 to 35 post-infection. When compared to controls, the total protein, urea, lactate dehydrogenase, aspartate aminotransferase and alanine aminotransferase were increased, while albumin, glucose and amylase were decreased. Both uric and ascorbic acids and glutathione dropped on day 2 and then increased significantly on days 6 to 12 and 6 to 14 post-inoculation, respectively. There was a two-fold increase in lipid peroxidation on days 4 to 8 post-inoculation.ConclusionsContrary to all expectations, the present study demonstrates that the European brown hare shows relatively low susceptibility to tularemia. Therefore, the circumstances of tularemia in hares under natural conditions should be further studied.