Eimeria burdai sp. n. (Apicomplexa: Eimeriidae), a new parasite species from subterranean African silvery mole-rat, Heliophobius argenteocinereus.

A new coccidian parasite of the genus Eimeria Schneider, 1875 is described from the subterranean African silvery mole-rat Heliophobius argenteocinereus Peters, 1846. Oocysts of Eimeria burdai sp. n. were subspherical to broadly ellipsoidal 17.8 (16-19) x 14.1 (12-15), with a shape index 1.2 (1.1-1.4). Oocyst wall was bilayered, smooth and colourless, approximately 1.0 thick. Outer layer was significantly thicker than inner one. A micropyle and oocyst residuum were absent. One or two ellipsoidal or spherical polar granules were present. Sporocysts were ellipsoidal, 10.8 (9-12) x 6.2 (5-8) with a shape index 1.7 (1.5-1.9). Sporocyst wall was single-layered, thin, smooth and colourless, with small Stieda body at the pointed end. In freshly sporulated oocysts, spherical sporocyst residuum was composed of small granules enclosed by a thin membrane. Sporozoites were elongate, lying length-wise in the long axis of the sporocyst, partially curled around each other, with single large refractile body located posteriorly. Faintly distinguishable nucleus was in the central part of the sporozoite. This eimerian represents the first coccidian species described from subterranean African silvery mole-rat (Rodentia: Bathyergidae).

Disturbed enamel formation in wild boars (Sus scrofa L.) from fluoride polluted areas in Central Europe.

The pathological alterations of enamel structure in the teeth of wild boars from fluoride polluted areas in N-Bohemia (Czech Republic) and S-Saxony (Germany) were studied on a macroscopic and a microscopic level. Mandibular bone fluoride concentration (mg F(-)/kg, dry wt; mean +/-SD, individuals <24 months of age) in the specimens from N-Bohemia (754.3+/-149.6) and S-Saxony (490.8+/-135.1) was significantly higher than that of controls (free of dental fluorosis), originating from the western part of Germany (304.7+/-91.0). Fluoride content in bulk enamel (mg F(-)/kg, ash wt) of fluorotic permanent teeth from N-Bohemia (382.1+/-165.2) and S-Saxony (125.0+/-38.3) was likewise significantly increased over that of non-fluorotic control teeth from W-Germany (33.6+/-26.7). Macroscopically, fluorosed wild boar enamel exhibited opacity and discoloration of varying extent, accentuated perikymata as well as hypoplastic and posteruptive surface defects. Microradiographic and scanning electron microscopic analyses revealed enamel subsurface hypomineralization, accentuated Retzius lines and occurrence of broad, hypomineralized incremental bands of abnormal structure underlying hypoplastic enamel surface defects. The presence of zones of aprismatic enamel was associated with these bands. Incremental bands with altered enamel structure and enamel surface hypoplasias, both denoting a severe disturbance during the secretory stage of amelogenesis, have previously been observed in rodents following acute parenteral fluoride dosing. It is concluded that in the chronically fluoride exposed wild boars periods of especially elevated plasma fluoride levels exerted an acute toxic effect on the secretory ameloblasts. A feature not previously reported from fluorosed enamel was the occurrence of canal-like structures that originated at the broad incremental bands and extended into the external enamel. The presence of these canals presumably results from a delay in the resumption of secretory activity by groups of ameloblasts following a fluoride insult. Based on experimental evidence in domestic pigs and in sheep, the overall subsurface hypomineralization of fluorosed wild boar enamel is attributed to a disturbance of enamel maturation. The distribution of fluorotic enamel changes within the dentition of the wild boars could be related to the developmental sequence of tooth formation in the species. Teeth whose crown formation took place prenatally (deciduous teeth) or largely pre-weaning (permanent first molars) exhibited no or only moderate fluorotic enamel alterations. Based on the extension of enamel surface hypoplasias along the coronoapical axes of the tooth crowns, the timing of excess fluoride exposure that caused a marked disruption of enamel matrix secretion was estimated in specimens with a known date of death. The results indicate that the wild boars had been exposed to a particularly severe fluoride impact during autumn and winter of their first year of life.

Monitoring regional fluoride pollution in the Saxonian Ore mountains (Germany) using the biomarker dental fluorosis in roe deer (Capreolus capreolus L.).

The spatial variation of fluoride contamination in the Saxonion part of the Ore mountains (Federal state of Saxony, Germany) was assessed by analysing the prevalence and severity of dental fluorosis in wild male roe deer aged 2 years or more (n = 794) from this region. The study area is exposed to increased atmospheric deposition of fluorides, originating from emission sources in the North-Bohemian brown coal belt. The severity of dental fluorosis in the permanent premolars and molars of one hemimandible per animal was assessed based on a scoring system and a dental lesion index of fluorosis (DLI) assigned to each specimen. On the basis of the mean DLI calculated for the roe deer originating from a certain municipal district, the respective deer sample was assigned to one of seven fluorosis categories, and a map showing the distribution of these categories was produced. Highest fluorosis categories were recorded for roe deer samples from the central and eastern parts of the study area that directly bordered on, or were located near to, the Czech-German border. A close spatial relationship between the main fluoride emission sources in North-Bohemia and the regions with the highest prevalence and severity of dental fluorosis in roe deer was discernible. The observed regional variation of fluoride pollution is in accordance with the results of other studies directly measuring fluoride deposition into the study area or fluoride levels in vegetation. A main advantage of the method used in this study over other ways of recording fluoride contamination of wildlife habitats is that it uses an established and continuously operated system of specimen collection, thereby enabling efficient monitoring with high spatial and temporal resolution at very low cost. Moreover, a clearly recognisable and relevant biological effect is measured which occurs in a dose-dependent manner over a range of environmentally relevant concentrations.

Pathological bone changes in the mandibles of wild red deer (Cervus elaphus L.) exposed to high environmental levels of fluoride.

A macroscopic, microscopic and scanning electron microscope study was performed on the pathological bone changes of the mandibles of wild red deer (n = 61) exhibiting severe dental fluorosis. The animals originated from a highly fluoride polluted area in Central Europe (Ore mountains and their southern foreland, Czech-German border region) and constituted 11.2 % of the studied red deer sample (n = 545) from this area. Pathologically increased wear and fracture of fluorosed teeth caused a variety of mandibular bone alterations, including periodontal breakdown, periostitis, osteitis and chronic osteomyelitis. As a further consequence of severe dental attrition, opening of the pulp chamber and formation of periapical abscesses were occasionally observed. In case of severe periodontal breakdown, loss of teeth from the mandibles was found. In addition to the inflammatory bone changes, the occurrence of osteofluorotic alterations was also diagnosed in the specimens with the highest bone fluoride concentrations (> 4000 mg F-/kg dry wt). These changes comprised extended apposition of periosteal bone onto the mandibular cortex as well as deformation of the mandibular body, which was attributed to a fluoride-induced osteomalacia. The present study provided circumstantial evidence that, in addition to fluoride induced dental lesions, the occurrence of marked periodontal disease and tooth loss is an important factor responsible for a reduction of life expectancy in severely fluorotic wild red deer.

Fluoride content and mineralization of red deer (Cervus elaphus) antlers and pedicles from fluoride polluted and uncontaminated regions.

Fluoride, calcium, and phosphorus content as well as ashpercentage and ash density of primary antlers and pedicle bones were studiedin nine yearling red deer stags from a fluoride polluted region in NorthBohemia (Czech Republic) and in nine control animals from two uncontaminatedareas in West Germany. Fluoride levels in antlers (845 +/- 257 mgF-/kg ash, mean +/- SD) and pedicles (1,448 +/- 461 mgF-/kg ash) of the N-Bohemian specimens exceeded that of thecontrols (antlers: 206 +/- 124 mg F-/kg ash, pedicles:322 +/- 157 mg F-/kg ash) by factors of 4.1 and 4.5,respectively. Antler and pedicle fluoride concentrations of the deer(n = 18) were closely correlated (r = 0.975,p < 0.001). Analyses of ash percentage and ash density revealed that theantlers of the N-Bohemian deer contained significantly less mineral and weresignificantly less dense than both their pedicles and the control antlers. Inthe pooled antler samples (n = 18), bone fluoride concentration wasnegatively correlated with ash density (r = -0.826, p < 0.001)and ash percentage (r = -0.759, p < 0.001), whereas nonsignificant, positive correlations existed for the pooled pedicle samples. Ash percentage and ash density of the antlers and their correspondingpedicles were uncorrelated. It is concluded that increased fluoride exposureof deer leads to reduced mineral content and mineral density of antler boneand that it is the rapidity of their growth and mineralization that makesantlers especially susceptible to fluoride action. Due to their ability toaccumulate high amounts of fluoride during a defined, limited timespan andthe apparently dose-dependent negative effect of fluoride on their densityand mineral content, (primary) antlers can be recommended as monitoring toolsfor studying environmental pollution by fluorides.

Structural changes in fluorosed dental enamel of red deer (Cervus elaphus L.) from a region with severe environmental pollution by fluorides.

A macroscopic, microradiographic and scanning electron microscope study was performed on the structure of fluorosed dental enamel in red deer from a fluoride polluted region (North Bohemia, Czech Republic). As was revealed by analysis of mandibular bone fluoride content, the rate of skeletal fluoride accumulation in the fluorotic deer was about 6 times that in controls taken from a region not exposed to excessive fluoride deposition. In all fluorosed mandibles, the 1st molar was consistently less fluorotic than the other permanent teeth. This was related to the fact that crown formation in the M1 takes place prenatally and during the lactation period. Fluorosed teeth exhibited opaque and posteruptively stained enamel, reduction or loss of enamel ridges, moderately to grossly increased wear and, in more severe cases, also enamel surface lesions of partly posteruptive, partly developmental origin. Microradiographically, fluorosed enamel was characterised by subsurface hypomineralisation, interpreted as a result of fluoride interference with the process of enamel maturation. In addition, an accentuation of the incremental pattern due to the occurrence of alternating bands with highly varying mineral content was observed in severely fluorosed teeth, denoting fluoride disturbance during the secretory stage of amelogenesis. A corresponding enhancement of the incremental pattern was also seen in the dentine. The enamel along the more pronounced hypoplasias consisted of stacked, thin layers of crystals arranged in parallel, indicating that the ameloblasts in these locations had lost the distal (prism-forming) portions of their Tomes processes. The findings of the present study indicate that red deer are highly sensitive bioindicators of environmental pollution by fluorides.

Mandibular bone fluoride levels and occurrence of fluoride induced dental lesions in populations of wild red deer (Cervus elaphus) from Central Europe.

Mandibular bone fluoride concentrations as well as frequency and intensity of fluoride-induced dental lesions were studied in four red deer populations from Czechia and Germany exposed to different levels of environmental fluoride. The degree of fluorosis in the permanent cheek teeth was recorded by a scoring system and the individual mandibles assigned to one of three categories (unfluorosed, slightly to moderately fluorosed, and markedly to severely fluorosed) on the basis of the tooth scores. An increase in the frequency and severity of dental fluorosis was positively associated with an increase in bone fluoride level, which itself was significantly different between the four samples. In all samples, the rate of bone fluoride accumulation was higher in younger than in older deer. The results of this study show that frequency and intensity of dental fluorosis can be used as valid indicators of increased fluoride exposure of deer populations, and thus as a quick, easy, economic and reliable means of monitoring fluoride pollution in areas inhabited by wild deer.

[Changes in the use of biologically effective fluorides and the consequences]. / Zmeny v príjmu biologicky efektivních fluoridu a nekteré dusledky toho.

The nearly 50-year dispute about the usefulness of public water supply fluoridation is basically a dispute about whether the human consumer can be given "optimum" doses of fluorides even in some communities with markedly less than 1 mg/1 F in drinking water. At the very beginning of this dispute, some basically conflicting epidemiological data were found (only seemingly so in our view): around the year 1940 the rate of dental caries in USA children dropped precipitously on drinking water with fluoride concentration growing at an interval of 0.1-0.5 mg/l; at higher concentrations the dental caries rate was declining increasingly less and less (and at concentrations of over 2 mg/l it began picking up again). In contrast to this, in the Federal Republic of Germany in 1950, the interval of 0.1-0.5 mg/l F was related to absolutely no decline in the dental caries rate which was practically as low as in the United States on drinking water containing 2 mg/l. These and other "contradictory" data are put down to man's different intake of fluorides coming from sources other than water. The main cause of different intakes of fluorides from food is apparently in the degree of intensity of field fertilisation with phosphates containing a marked proportion of fluorine, in other words, different intensity of agricultural land fluoridation. In Germany, 23 kg of P2O5 per hectare of arable land was used as early as in 1935, while in the United States this intensity was not reached until 1985.(ABSTRACT TRUNCATED AT 250 WORDS)