Further study of Codiostomum struthionis (Horst, 1885) Railliet and Henry, 1911 (Nematoda, Strongylidae) parasite of ostriches (Struthio camelus Linnaeus, 1758) (Aves, Struthioniformes)

Codiostomum struthionis is a nematode parasite of the ostrich caecum. Little is known about its pathology, being considered by many authors as a non-pathogenic parasite. Infections by C. struthionis are sometimes overlooked because its eggs are indistinguishable from another ostrich nematode, Libyostrongylus spp. Fecal cultures and infective larvae identification are necessary for proper identification. The aim of this study is to provide improved morphological characterization of adults and infective larvae of C. struthionis. Ten caeca of adult ostriches were collected and washed in 0.09% saline solution. Male and female nematodes were collected and quantified separately. Nematodes were fixed in A.F.A. for optical microscopy or fixed in Karnovsky solution for scanning electron microscopy. To obtain infective larvae, fecal samples were collected at sites of high concentration of parasites in the caeca and fecal cultured. The resultant larvae were identified and measured with light microscope at 400x. Nine of the 10 slaughtered ostriches were parasitized by C. struthionis. All nematodes were found in the distal third of the caeca. A total of 566 parasites were recovered (234 males and 332 females). All the cultured larvae had characteristics of C. struthionis (rounded cephalic region with a flat extremity, an acute larvae tail termination and a long and filamentous sheath tail). All the adult parasites were characterized as C. struthionis. Through the analysis of the infective larvae it was determined that the morphology of the larvae tail was the best trait to use in the distinction of this species (live bird diagnosis).     

Veterinary practice and occupational health

Summary

The prevalence of allergy, lung function disorders, and bronchial hyperreactivity was studied in 102 Dutch veterinarians, subdivided into five professional groups (predominantly working with either swine, cattle, poultry, companion animals, or as a non‐practitioner). The mean age of the participants was 43 years; 6 participants were females. Twenty‐two per cent of the participants were overweight, and relatively more non‐practitioners than practitioners were overweight. Approximately 23% of the vets reported complaints of prolonged fatigue. The data suggest a relationship between complaints of prolonged fatigue and a more than average number of daily working hours. Only a small proportion of vets were sensitized against several allergens. There were no significant differences in prevalence of distinct lung function disorders or bronchial hyperreactivity between professional groups. It is hypothesized that the respiratory complaints (chronic coughing, chronic phlegm production, stuffed nose, sneezing) reported by the vets predominantly working in swine and/or poultry practice could be caused by irritation and/or inflammation of the first part of the trachea‐bronchial tree that has no measurable and permanent consequences for changes in lung function or increased bronchial hyperreactivity. The results of a skin test against allergens and determination of allergen‐specific IgE in blood indicated that the respiratory complaints were probably not related to allergy against the panel of allergens tested.     

Food and feeding habits of Oreochromis mossambicus (Peters) in hypertrophic Hartbeespoort Dam,South Africa

The diet of 745 Oreochromis mossambicus (Peters) of less than 0,5 up to 2000 g wet mass, in Hartbeespoort Dam, was determined from stomach content analysis. Samples of fish were selected to cover a whole annual cycle. Small fish fed initially on zoobenthos and zooplankton, but fish with a mass of over 4 g fed increasingly on Microcystis aeruginosa Kutzing and detritus until these food items formed the dominant food source in O. mossambicus over 8 g. Some cannibalism was encountered in fish up to 64 g in the summer months. The ratio of intestinal length to total length of fish ranged from 0,58 in the smaller fish to 11,02 in larger fish and this indicated that there was an ontogenetic adaptation from a carnivorous to a phytoplanktivorous/detritivorous diet. Feeding in juvenile fish studied over 24 h was found to be most intense in the early morning and late afternoon but remained high throughout daylight hours decreasing considerably at night. The daily ingestion rate of food in O. mossambicus in Hartbeespoort Dam was estimated at 453 mg/g of fish. This comprised 45% M. aeruginosa and 55% detritus. It was apparent that of this matter ingested only a small percentage would be assimilated. Oreochromis mossambicus shows feeding and breeding preadaptations which enable it to successfully exploit a lacustrine environment. These adaptations enable it to maintain a large population in Hartbeespoort Dam despite frequent winter mortalities caused by water temperatures below their tolerance limits.     

Complex polysaccharide inclusions in the skeletal muscle of stranded cetaceans

Skeletal muscle samples were examined post-mortem in 148 cetaceans over a 12-year period. Histological analysis included haematoxylin and eosin (HE) and periodic acid-Schiff (PAS) staining with and without diastase digestion. In addition, histological muscle sections were immunostained for ubiquitin and fast and slow heavy-chain myosin isoforms. PAS-positive, diastase-resistant inclusions were detected in 26 animals from 11 different species. Older cetaceans were preferentially affected. These intrafibre inclusions varied from large aggregates to multiple coarse granules and were typically associated with type II fibres. All diastase-resistant inclusions were positive for ubiquitin. These features resembled those inclusions described as complex polysaccharide in horses. Based on these histological findings and the ubiquitin staining pattern, a morphological diagnosis of complex polysaccharide storage myopathy is proposed.     

From killer to carer: steroid hormones and paternal behaviour

Mammalian parental investment (i.e. care of descendant offspring) is largely biased towards maternal contributions due to the specific feeding needs of mammalian offspring; however, varying degrees of paternal investment have been reported in about 10% of all mammalian species. Within the order Carnivora, paternal contribution to rearing offspring is particularly high: an estimated 32% of all studied carnivore species exhibit direct paternal care. Despite the prominence of paternal investment in carnivores, the endocrine basis of this behaviour is not well understood. This review examines the current – highly constrained – state of knowledge about the endocrine basis of carnivore paternal investment. We attempt to link changes in androgen and glucocorticoid levels with variation in direct and indirect paternal care behaviour making specific predictions regarding the way forward. Well-studied species, such as bat-eared foxes (Otocyon megalotis), dwarf mongoose (Helogale parvula) and meerkats (Suricata suricatta), where social dynamics are relatively well understood, can act as ideal model systems through which we may further investigate the endocrine basis of paternal investment in carnivores.     

Positive Streptobacillus moniliformis PCR in guinea pigs likely due to Leptotrichia spp

Streptobacillus moniliformis is a zoonotic bacterium. We obtained positive S. moniliformis PCR results in oral swab samples from guinea pigs from an experimental colony and the breeding colony of origin. Comparison of the DNA sequence of an amplicon with deposited 16S rDNA sequences revealed that Leptotrichia sp. can be the source of a false positive S. moniliformis PCR outcome.