Streptococcus suis serotype 2 infection in pigs: new diagnostic and pathogenetic aspects.

In a study aimed at improving the diagnosis and elucidating the pathogenesis of Streptococcus suis serotype 2 infection in pigs, a combination of bacterial culture and histopathological and immunohistochemical examination was applied to a range of tissues from 42 naturally infected pigs with typical macroscopical lesions. By culture, 21 pigs (50%) were shown to be systemically infected with S. suis serotype 2; seven (17%) were infected with S. suis serotype 7, two with other bacteria, and 12 yielded no bacterial pathogens. The highest isolation rate for S. suis serotype 2 was obtained from the lateral cerebral ventricles and other regions of the brain, whereas the bacterium was only rarely isolated from the liver or spleen. Immunohistochemically, a diagnosis of S. suis serotype 2 infection was obtained in two of 12 (17%) animals from which no pathogens had been cultured. Moreover, immunohistochemistry differed from culture in revealing a greater number of positive tissue specimens. The microanatomical distribution of bacteria pointed toward the pharyngeal and palatine tonsils as principal portals of entry. Furthermore, S. suis serotype 2 bacteria were frequently identified immunohistochemically in the regional lymph nodes of the upper respiratory tract, possibly reflecting primary lymphogenous spread from the tonsils.

Otitis interna is a frequent sequela to Streptococcus suis meningitis in pigs.

Twenty-eight histologically confirmed cases of porcine leptomeningitis were examined retrospectively, with focus on the pathology of the inner and middle ear, brain, and vestibulocochlear nerve. Tissues were evaluated by histology and immunohistochemistry for Streptococcus suis serotype 2 antigen, and the bacteriologic results were recorded. Exudative otitis interna was diagnosed in 20/28 pigs (71%). The lesions primarily affected the perilymphatic ducts, with consistent involvement of the scala tympani. Perineuritis of the vestibulocochlear nerve was seen in all but four of the ears affected with otitis interna. Immunohistochemically, S. suis serotype 2 antigen was demonstrated in the leptomeningeal, perineural, and labyrinthine exudates in 11 cases. Otitis media was diagnosed in 10/28 pigs (34%), but evidence of extension to the inner ear was not observed. The findings were highly similar to descriptions of meningogenic labyrinthitis in humans and in laboratory animal models. Otitis interna in pigs can also develop via the meningogenic route and is not always, as generally stated, tympanogenic.

Pneumocystis carinii Delanoë & Delanoë, 1912 found in lungs of freeliving animals in Denmark at autopsy.

Stained imprints made from autopsy lung biopsies from hares, foxes, badgers, stone martens, one hedgehog, roe deer from Denmark and from caribou from Greenland were examined microscopically for Pneumocystis carinii. Pneumocysts were found in the lungs of 3 out of 28 hares, 3 out of 18 foxes and 1 out of 6 roe deer. This is the first report of Pneumocystis carinii in hares, foxes, and roe deer in Denmark. It seems to be the first report of Pneumocystis carinii in roe deer.

Heavy metals (cadmium, copper, lead and mercury) in common eiders (Somateria mollissima) from Denmark.

In an examination of 50 Danish common eiders, the liver and kidney content of cadmium, copper, lead and mercury was determined. Eiders were chosen for analysis, because this species feed almost exclusively on the common mussel (Mytilus edulis), which is known to accumulate heavy metals. The concentrations recorded of cadmium, copper, and mercury were lower than what is usually regarded as toxic for birds, except for one eider which carried more than 2000 mg copper/kg liver tissue (dry weight). Of the 42 eiders analysed for lead, four had toxic levels, i.e., more than 7 mg per kg liver wet weight, and two other had increased levels, i.e., 3-7 mg lead per kg liver wet weight. The mean Cd concentration was 3.3 mg/kg liver (ww). This means that by consumption of ab. 160 gram liver from the common eider, the weekly tolerable intake of cadmium suggested by FAO/WHO would be exceeded.

Lead burden in mute swans from Denmark.

During the severe winter of 1978-79, large numbers of mute swans died in coastal areas in Denmark; of these 2111 were collected for autopsy. The area of origin and the sex of the 2111 swans, 184 of which were ringed, are given in Table I and Fig. 1. At autopsy (Table II) most of the swans were recorded as having died from starvation. Lead pellets were found in only 0.7% of the gizzards (Table III) probably because most ingested pellets had been eroded away before the swans died. The results of analysis of 76 swans selected at autopsy and of the 184 ringed swans show that lead poisoned swans are not always recognized at autopsy (Table III and IV). Ten per cent of the ringed swans carried more than 7 mg lead per kg liver wet weight (Ww) and 34% more than 3 mg/kg (Ww) (Table IV), while an elevated lead content (greater than 30 mg/kg dry weight) was found in the sternum of 40% of the swans (Fig. 2). The load of lead in the liver was higher in the few swans from the western part of Jutland than in swans from the main sampling areas, while in the sternum it was relatively lower in swans from the southern part of the country (Lolland, Falster) (Table V). No difference in lead content was found between males and females. The lead content in the liver was not correlated with age, while a positive correlation was found between age and the lead content in the sternum (Table VI).(ABSTRACT TRUNCATED AT 250 WORDS)

Heavy metals (copper, cadmium, lead, mercury) in mute swans from Denmark.

During the severe winter of 1978-79, large numbers of mute swans died in coastal areas of Denmark. Of these, 2111 were collected for examination. The analyses confirm previous findings of relatively high copper levels in mute swans (mean for 178 livers was 2680 mg/kg dry weight (Dw) and for 110 kidneys 34 mg/kg Dw) (Table I, Fig. 1). The copper content was not related to sex or age (Table II). The highest liver levels of copper were found in swans from Western Jutland. Cadmium was found at the same relatively low levels as recorded for waterfowl elsewhere (mean for 178 livers was 12 mg/kg Dw, for 110 kidneys 24 mg/kg Dw) (Table I, Fig. 2). The cadmium content was not sex-related, but it increased with age (Table II). The mean mercury content (liver) was 1.4 mg/kg Dw in the 10 birds analysed (Table I). The mean lead content was 15 mg/kg Dw in the 178 livers analysed and 31 mg/kg Dw in 110 sternum (Table I and Fig. 3). The lead content was not sex-related. In sternum, but not in livers, it was related to age (Table II). One third of the swans were found lead-contaminated probably after ingestion of lead pellets. None of the swans carried high levels of both copper, cadmium, and lead (Table III).

The incidence of Salmonella bacteria in wild-living animals from Denmark and in imported animals.

In a 6 year examination (1975-80) of 3036 game mammals and 3004 game birds from Denmark, and of 684 warm-blooded animals of foreign origin, Salmonella was found in 0.2% of Danish mammals, 0.8% of danish game birds, and 0.1% of the animals of foreign origin. Furthermore, Salmonella was isolated from 16% of 605 mute swans which died from starvation during the winter 1978-79, and from 2.4% of 296 faeces samples from hooded crows. Even though the occurrence of Salmonella among Danish cattle has been increasing during recent years, this does not seem to be the case among game, mallards excepted. Mallards raised in breeding units are often treated with antibiotics as a routine; in this way the mortality due to Salmonella is reduced, but some birds will still carry Salmonella bacteria when released. The high salmonella frequency among the mute swans that died during the winter of 1978-79 was probably a result of large numbers of birds gathering in harbours or in small stretches of open water near sew outlets.

Summer mortality among caribou calves in West Greenland.

Colibacillosis with polyarthritis, due to E. coli O-group 55, has been found to be responsible for a high summer mortality among caribou valves in West Greenland. The mortality is presumably consequential on overstocking and therefore likely to subside as the caribou population in the preferred habitats is reduced to a lower density--the optimum level of which is as yet unknown.