[Case report. Treatment of the gillworm disease (Dactylogyrosis) of some South American cichlids and catfish]. / Beobachtungen zur Behandlung des Kiemenwurmbefalls (Dactylogyrose) bei einigen südamerikanischen Buntbarschen und Welsen.

The infection with gillworms (Dactylogyrus sp.) causes severe problems in the keeping and breeding of tropical ornamental fishes, e.g. Discus (Symphisodon aequifasciata). Treatment of gillworm disease with different drugs has been shown in the past to be insufficient. Therefore, the effectiveness of a long-term use of praziquantel was evaluated in ornamental fish. Cumulative doses up to 10 mg praziquantel/l water were tolerated without side-effects by Angel Fish (Pterophyllum scalare), Discus, and a variety of catfish species (Ancistrus sp., Corydoras sp.). It was found appropriate to start with a dosage of 2.5 mg/l and to add the same dosage every other day several times. All adult parasites and larvae were killed by this treatment. For the complete elimination of the Dactylogyridae-population in a closed aquarium system, 3 therapy-cycles (duration: 5-6 d, accumulated dosage: 2.5 mg/l/d) prooved to be effective. It was important to interrupt the therapy-cycles with intervals without medication (1 to 4 weeks).

Acute and long-term humoral immunity following active immunization of rabbits with inactivated spores of various Encephalitozoon species.

Microsporidia of the genus Encephalitozoon are increasingly being reported as a cause of severe, often disseminated infections, mainly in patients with acquired immunodeficiency syndrome (AIDS). Immunological identification of each of the three recognized species (E. cuniculi, E. hellem, and E. intestinalis) requires the availability of specific immune sera. All sera available thus far have been generated by direct inoculation of rabbits with virulent microsporidian spores. This study demonstrates for the first time that subcutaneous immunization with inactivated spores of E. cuniculi, E. helleri, or E. intestinalis is capable of generating highly active rabbit hyperimmune sera to the homologous antigens, with maximal titers being 1:5,120, 1:1,280, and 1:2,560, respectively, as determined by the indirect immunofluorescence technique (IIF). Broad cross-reactivity of the rabbit antisera with all heterologous Encephalitozoon antigens was determined by IIF and immunogold electron microscopy; however, only the E. hellem immune serum strongly cross-reacted with spores of Enterocytozoon bieneusi. During the 35-month follow-up period the antibody titers to the homologous antigens declined to 1:640, 1:160, and 1:320, respectively. The observed decay curves for antibody titers against E. cuniculi, E. hellem, and E. intestinalis were fitted using mathematical modeling, resulting in a predicted duration for specific immune responses of about 7 years on average. Knowledge of the magnitude and duration of specific immune responses is a prerequisite for further evaluation of the concept of using inactivated microsporidian spores in the quest for vaccines against microsporidian infections.

Poor quality of oocytes from Xenopus laevis used in laboratory experiments: prevention by use of antiseptic surgical technique and antibiotic supplementation.

BACKGROUND AND PURPOSE: Episodic phases of continuous poor-quality oocytes obtained from South American Clawed Frogs (Xenopus laevis) often are observed. In publications dealing with the surgical technique of oocyte removal, the frogs' robust constitution and resistance against infections provided by magainins are pointed out. For this reason, clean rather than sterile conditions for the surgical procedure are mostly recommended. However, in most instances, antibiotics are added to the buffer medium when in vitro experiments are performed using oocytes. METHODS: After a long phase of poor oocyte quality at our facility, involving oocytes that had been obtained by use of a "clean" surgical procedure, we subsequently cultured oocytes in a buffer medium containing the three antibiotics: penicillin G, gentamicin, and streptomycin. RESULTS: During DNA injection experiments, the oocytes developed black spots on their surface by postoperative day two. Pure culture of the gram-negative non-fermentative rod Pseudomonas fluorescens was obtained from the impaired oocytes; the isolate was resistant to the three antibiotics. By contrast, after aseptic surgical removal and culture of oocytes in buffer medium containing the antibiotics tetracycline and gentamicin, perfect oocytes without bacterial contamination were obtained. CONCLUSION: Whenever impaired oocyte quality is observed, microbial contamination should be considered as a possible cause.

[Cutaneous asthenia (Ehlers-Danlos syndrome) in a domestic rabbit]. / Kutane Asthenie (Ehlers-Danlos Syndrom) bei einem Hauskaninchen.

Cutaneous asthenia is a connective tissue disease primarily of dogs and cats, resembling Ehlers-Danlos syndrome in man. This is a description of the disorder in a rabbit. The one-year-old female animal was presented because of two large gaping wounds of the skin. Clinical examination revealed a hyperextensible, thin, and fragile skin. The degree of skin extensibility was evaluated by means of a skin extensibility index (SEI: 19.2%) and compared with those of 4 healthy rabbits (SEI: 8.3%-14.3%). Clinical diagnosis was confirmed by histopathological examination of a skin biopsy revealing reduced packing density of collagen fibers. In addition a decreased number of hair follicles was observed. No conclusion could be drawn regarding the etiology, but existing literature strongly suggests a genetic cause (mostly autosomal dominant inheritance) in humans as well as in animals.

Anthelmintic treatment to eradicate cutaneous capillariasis in a colony of South African clawed frogs (Xenopus laevis).

The nematode Capillaria xenopodis (Pseudocapillaroides xenopi), a skin parasite of South African clawed frogs (Xenopus laevis), is quite common in laboratory animal facilities. It causes serious skin changes and may further lead to wasting and death of affected frogs. Various treatment protocols, using the anthelmintics ivermectin and levamisole, were successively tested for practicability of elimination of the parasite from a colony of clawed frogs. Nematodes were reduced below diagnostic levels by various methods of application of ivermectin (orally or by injection into the dorsal lymph sac, twice at intervals of 10 to 14 days). However, nematodes were found again in the treated animals 1 to 3 months later. Treatment by use of ivermectin-medicated tank water is not feasible due to its low water solubility. Elimination of the parasite was reliably achieved by use of levamisole-medicated tank water. Relapses were not seen during the 18-month posttreatment observation period. Levamisole concentration was 12 mg/L of water, with 4.17, 5.00, or 6.25 L of tank water/frog, and 50, 60, or 75 mg of levamisole available/frog, for at least 4 days, with treatments repeated after 10 to 14 days. Results were reproducible in two trials each with five tanks containing, in turn, four or five frogs each. A treatment trial carried out with a group of 20 adult frogs exposed to 12 mg of levamisole/L of tank water, but with only 2.5 L of tank water/frog (i.e., only 30 mg of levamisole available/animal), was not effective in eradicating the parasites. Not only the drug concentration, but also the amount of drug available per animal seems to be of importance. In contrast to thiabendazole, which is often reported in literature as treatment for cutaneous capillariasis, negative side effects were not observed with use of levamisole.

Influence of feeding hay on the alopecia of breeding guinea pigs.

Animals with partial alopecia were seen frequently in a breeding colony of guinea pigs. No pathologic aetiology could be determined. An influence of nutrition on the density of the hair coat was considered. Breeding groups were fed one of the commercial guinea pig diets of differing composition, with or without the addition of hay. Observation occurred over a period of months and the quality of the hair coat was evaluated periodically using a semi-quantitative scoring system. More extensive and more frequent fur defects were found is guinea pigs receiving a breeding diet with a high content of crude protein (23%) and a low level of crude fibre (12%), offered hay only restrictively compared with animals receiving a diet with a lower content of crude protein (15.5%) and a higher level of crude fibre (19.5%), offered the same amount of hay. The amount of hay offered is of paramount importance. Animals fed only the diet with the higher level of crude fibre (19.5%), according to the manufacturer's instructions as a complete food, without the addition of hay, showed a less dense hair coat within 4 weeks. In our colony a group of five breeding animals and their young required 200 g of hay daily in order to improve their hair coat quality to normal. Conversely, animals receiving less hay had progressively deteriorating hair coat density. Not only the amount of hay offered, but also the accessibility for all animals plays a role in preventing alopecia in guinea pigs. In larger cages (twice the usual ground surface area) fur defects were seen when the same amount of hay (200 g) was offered in only one central area, rather than spread out evenly throughout the cage. Hair loss was observed to be the result of trichophagia between adult animals kept in the same cage. The need for crude fibre of breeding animals does not appear to be completely met by pellets rich in fibre segments.

Effect of age on synthesis of the GABAergic steroids 5-alpha-pregnane-3,20-dione and 5-alpha-pregnane-3-alpha-ol-20-one in rat cortex in vitro.

Progesterone 5-alpha-reductase activity and 3-alpha-hydroxysteroid dehydrogenase activity were determined in the cortex of male and female rats in vitro. Age effects were investigated. The age of the male rats was 3-23 months, and that of the female rats 4-23 months. On addition, we investigated the enzyme 3 beta-hydroxysteroid oxidoreductase, 5-ene-isomerase in rat cortex in order to estimate the local synthesis of progesterone from pregnenolone. We found age-related increases in progesterone 5-alpha-reductase activity in the female rats (r = 0.64, p < 0.01, n = 6) and in the male rats (r = 0.5, p < 0.05, n = 18). 3-alpha-HSDH activity remained constant with age in female and male rats. The ratio of 3-alpha-hydroxysteroid dehydrogenase activity to 5-alpha-reductase activity tended to decrease with age (not significantly) in both male rats (r = -0.45, p = 0.06, n = 19) and the female rats (r = -0.36, p = 0.17, n = 16). We could not detect significant metabolism of pregnenolone to progesterone in rat cortex in vitro. The sensitivity of the assays of 3 beta-hydroxysteroid oxidoreductase, 5-ene-isomerase was calculated from the mean of the blank values + 3SD; the sensitivity of the assay was calculated as 0.103 fmol/mg protein/min. No significant metabolism of pregnenolone could be detected in cortex pooled from several male rats. The mean metabolism of progesterone was 1,200 times higher than the detection threshold of the assay for 3 beta-hydroxysteroid oxidoreductase, 5-ene-isomerase. We conclude that modifications of the inhibitory effects of the GABAergic steroids 5-alpha-pregnane-3,20-dione and 5-alpha-pregnane-3-alpha-ol-20-one via altered progesterone metabolism in rat cortex are possible with aging. A connection with the age-related increase in incidence of epileptic attacks, and with age-related changes in the effects of anticonvulsant and GABAA-active drugs, appears possible.

Hereditary compulsive self-mutillating behaviour in laboratory rabbits.

During the last few years an increasing number of cases of extensive automutilation has been observed in a rabbit breeding colony of Checkered crosses. Digits and pads of the front feet were traumatized. No other behavioural abnormalities or signs of disease were evident. Self-mutillation was seen both in stock, breeding and experimental animals, in rabbits kept singly in cages and in those housed in groups on the ground, in rabbits kept in different buildings and under the care of different staff members. This behavioural abnormality of Checkered crosses has also been observed in animals after being placed into other institutions or private homes. No evidence of an agent responsible for the occurrence of self-injury could be found with parasitological, mycological, histological, clinical or haematological examination. Twelve to 16 animals are affected yearly in a colony varying in size between 130 and 230 rabbits. Following complete healing, relapses occurred up to 3 times per year, on either the same or the opposite front foot. In the last 21 cases episodes of automutillation could be regularly interrupted with the dopamine antagonist, haloperidol. Similar signs of auto-mutillation were never seen in animals of another breeding line kept in the same building and under the same conditions nor in animals brought in from other breeding colonies. A relatively high coefficient of inbreeding can be presupposed in this 15-year-old breeding colony of Checkered crosses. A genetic predisposition for the behavioural anomaly described appears very likely.

Growth of Xenopus laevis under different laboratory rearing conditions.

Since the European frogs (Rana spp.) have fallen under the German endangered species regulation, Xenopus laevis (South African Clawed Frog) is being used increasingly in animal research and education. Optimal growth rates and homogeneity of groups have not necessarily been attained as little statistical analysis of growth data has been available. Following metamorphosis, an as yet not understood variability of growth is exhibited by X. laevis. In this study the effect of environmental factors on this variability was determined. Feeding, population density, background colouring, water temperature, the availability of hiding places, water level and water care were each examined separately. Development of body weight and body length were recorded. A definite correlation between the feeding programme, population density, cover and water care on the one hand and growth on the other were seen. Of lesser importance were water temperature, water level and background colouring. The observed variability of growth is assumed to also be of ethological origin.

[Bite wounds in young rabbits inflicted by adults of the same breed as a result of incomplete group separation (case report)]. / Bissverletzungen bei Jungkaninchen durch adulte Artgenossen infolge unvollständiger Gruppentrennung (Fallbericht).

Domestic rabbits should be able to exhibit their species specific behaviour patterns, including social contact, despite being kept in cages or in pens. Numerous housing systems have been studied and tried recently with the aim of providing appropriate keeping conditions for these animals (GEROLD, 1993). However, apparently optimal housing systems can lead to unexpected problems. Rabbits of two newly established pens were separated by a coarse-meshed (3 x 3 cm) grating allowing visual and tactile contact. Through this grating adult rabbits inflicted bite wounds to the front feet or the nasolabial regions of the weaned animals housed on the other side. Deep bites and lacerations requiring treatment occurred. Contact between separately housed rabbits must be restricted sufficiently to prevent the injuries described here.

Invasive Trichosporon beigelii infection in immunosuppressed rats.

Fulminant systemic mycoses were seen as complications in rats undergoing drug trials for the treatment of Pneumocystis carinii pneumonia. Rats were immunosuppressed with corticosteroids and by feeding with a low-protein diet. Homogenized pulmonary tissue from a rat with pneumocystosis was inoculated transtracheally. Secondary invasive mycosis was found in 56 of 59 rats examined. Trichosporon beigelii was identified as the causative agent in the majority of cases. After examining possible sources of infection, a Pneumocystis inoculum contaminated with fungi was found to be the obvious source. T. beigelii infections are becoming increasingly significant in immunocompromised human patients. The need for suitable and reproducible animal models is therefore also increasing. Observations described in this paper may help in the further development of such models.

[Physiologic hypothermia of newborn kittens up to 6 weeks old]. / Physiologische Hypothermie der Katzenwelpen bis zur 6. Lebenswoche.

Kittens showed a physiological hypothermia until they were 6 weeks of age. In the first 3 weeks of age rectal temperature was constantly low (37.6 +/- 0.3 degrees C). A linear increase of rectal temperature followed from the fourth to the sixth week of age inclusively and from the seventh week on rectal temperature reached the final temperature level (38.4 +/- 0.3 degrees C). This finding has to be considered in clinical assessment of kittens' body temperature.

The influence of genotypes and social ranks in the clinical course of an experimental infection with Mycoplasma pulmonis (MRM) in inbred rats.

Social ranks of healthy, adult male inbred rats housed in groups of four per cage were determined by their relative differences in intromission and ejaculatory patterns observed repeatedly under competitive copulatory conditions. Once ranked they were inoculated with M. pulmonis by contact with castrated females suffering clinically from M.pulmonis.--Body weight reduction and scores for laryngo-bronchotracheal breathing sounds and dispnoea or sneeze or wipe and the titers of specific antibodies were continuously observed during 123 days of illness. Studies were done in five series concerning the inbred strains AS/Ztm, LEW/Ztm, BH/Ztm. Genotypic differences accounts for 60-80% of the variability of the illness. LEW/Ztm was the most affected strain. Only in strain LEW/Ztm week correlations were shown between social rank before the infection (characterized by sexual activity under competitive conditions) and the scores for breathing sounds, dyspnoea and sneeze and wipe. Animals high in social rank showed a milder clinical course of the infection.

Streptococcus canis arthritis in a cat breeding colony.

This is the first description of a pathologic condition--arthritis in cats affecting mainly one joint, i.e. monarthritis--caused by Streptococcus canis (S. canis), of the Lancefield serologic group G. Six cases were recorded in a closed cat breeding colony during a 6 month period in 1988, and one additional case in 1990. Therapy with penicillin and streptomycin led to full recovery in four of six cases. The bacterium had been detected from different purulent processes sporadically--including one case of purulent arthritis in 1982--as a nosocomial infection since 1980, the year the breeding colony was established. A possible genetic predisposition (high inbreeding) may have contributed to the accumulation of the six cases in 1988. Although S. canis was isolated in mouse, rat, rabbit and dog, cat and man seem to be more frequently affected. There are some similarities between S. canis-arthritis in cat and man.

Mastomys natalensis or Mastomys coucha. Correct species designation in animal experiments.

Haemoglobin electrophoresis and chromosome analysis indicate that the widely used multimammate rat (chamois coloured) as experimental animal belongs to the species Mastomys coucha (Smith, 1836) and not, as commonly assumed, to Mastomys natalensis (Smith, 1834).