Mercury Content in Organs and Tissues of Indigenous (Vulpes vulpes L.) and Invasive (Nyctereutes procyonoides Gray.) Species of Canids from Areas Near Cherepovets (North-Western Industrial Region, Russia)

Trophic and spatial components of ecological niches of two canids native Vulpes vulpes and introduced Nyctereutes procyonoides are overlapping partially in the studied region. Maximum concentrations of mercury in predatory mammals of Canidae family from surroundings of Cherepovets have been determined in liver and kidneys (over 0.50 mg/kg wet weight), with minimal concentrations in brain (<0.2 mg/kg wet weight). The amount of mercury in the same organs of the red fox and raccoon dog is not significantly different. These levels of mercury content are noticeably higher than those in the predators of Canidae family that inhabit territories of Europe lacking the local sources of mercury. At the same time, absolute values of metal quantity are commensurable with the levels registered in predators from the mercury polluted regions of Spain and Poland.

Atrioventricular valvular anomalies and their role in the etiopathogenesis of cardiorespiratory syndrome in farmed common foxes (Vulpes vulpes)

BACKGROUND

Cardiorespiratory syndrome of common foxes is associated with a mortality rate ranging from 2.1% to 20%.

OBJECTIVE

The aim of this study was to analyze the prevalence of cardiac abnormalities in common foxes (Vulpes vulpes) from Polish farms with a history of cardiorespiratory syndrome.

ANIMALS AND METHODS

The prevalence of cardiac abnormalities in common foxes from a Polish farm with a history of cardiorespiratory syndrome was assessed as well as morphological examination of 60 heart specimens from clinically healthy animals. In addition, 38 foxes were examined echocardiographically and subjected to postmortem examination.

RESULTS

Atrioventricular valvular abnormalities were found in 57 out of the 98 (58%) analyzed hearts. The abnormalities of the mitral valve documented in more than 20% of the foxes in involved tendinous chords (completely lacking or shortened), papillary muscles and mitral cusps associated with both insufficiency and stenosis of the left atrioventricular orifice. Abnormalities of the tricuspid valve included significant shortening of the tendinous chords and thickening of the valve cusps with the impairment of their mobility. The results of the echocardiographic and postmortem examination were consistent in 79% of the cases. The specimens collected from animals with and without atrioventricular valvular anomalies did not differ significantly in terms of cardiomyocyte width, number of inflammatory cells, adipose tissue content and presence of polychromatic cardiomyocytes.

CONCLUSION

Congenital atrioventricular valvular defects may be involved in the etiology of cardiorespiratory syndrome in common foxes, and echocardiography can be used as a measure of stock's health and a criterion for selection for mating.