Oral doxycycline, niacinamide and prednisolone used to treat bilateral nodular granulomatous conjunctivitis of the third eyelid in an Australian Kelpie dog

A 5-year-old, female neutered, Australian Kelpie presented with a 2-month history of dramatic bilateral erythematous thickening of the third eyelids. Ophthalmic examination demonstrated raised, pink to red, irregular thickening of the entire palpebral surface of both third eyelids. There were no other ocular abnormalities. A surgical biopsy was taken from each third eyelid. Histopathologic examination revealed sheets of macrophages, plasma cells, lymphocytes, and occasional fibroblasts and neutrophils infiltrating the third eyelid stroma. A diagnosis of chronic granulomatous conjunctivitis was made. Grossly and histopathologically this case closely resembles previously described cases of nodular granulomatous conjunctivitis involving the third eyelids of Collie dogs. This report describes an unusual case of nodular granulomatous conjunctivitis isolated to the third eyelids in an Australian Kelpie. Resolution of the condition was achieved with a combination of oral doxycycline, niacinamide and prednisolone.     

Internal parasites of possums (Trichosurus vulpecula) from Kawau Island, Chatham Island and Stewart Island

As part of a search for pathogens that might be useful agents for biological control of possums, the three largest offshore islands of New Zealand that still have possums were surveyed to determine the pathogens present in these isolated populations. Brushtail possums from Kawau Island (n = 158), Chatham Island (n = 214) and Stewart Island (n = 194) were examined for internal parasites. Possums from Kawau Island were infected with Eimeria spp. (16.7%), Bertiella trichosuri (5.2%) and Purustrongyloides trichosuri (15.5%). No Paraustrostrongylus trichosuri or Trichostrongylus spp. were found. Possums from Chatham Island were infected with Eimeria spp. (10.9%). Bertiella trichosuri (3.6%), T colubriformis (6.6%), T retortaeformis (1%) and T. vitrinus (0.5%). No Parastrongyloides or Paraustrostrongylus spp. were found. Possums from Stewart Island were infected only with Eimeria spp. (4.6%). Because of their paucity of some parasites, the opportunity exists to use these offshore islands to study the introduction and spread of a parasite into a possum population, and what technology would be required to bring it to hyperendemicity.     

Foraging and denning patterns of brushtail possums, and their possible relationship to contact with cattle and the transmission of bovine tuberculosis

Radio-tracking and direct observation were used over 18 months in 1990-92 to investigate both the use of sleeping dens and foraging activity by possums (Trichosurus vulpecula) on a 21 ha site in the Wairarapa used for a longitudinal study of bovine tuberculosis. Males had larger home ranges than females, and both sexes had larger activity areas during the autumn mating season than at other times of the year. Possums typically foraged in only a small area of their home ranges (termed an activity area) on any one night, and the areas used by individuals were commonly very similar over a series of nights. Activity areas overlapped extensively among possums. Possums used a limited number of dens, commonly in a small and in most cases a circumscribed part of their home range. No simultaneous den-sharing was found, with the exception of mother-joey pairs. The mortality of juveniles after independence was 36%. Only two of 25 juveniles under surveillance to detect dispersal dispersed more than 500 m off the study site, and both subsequently died. Grazing patterns of cattle meant that almost all accessible areas of the paddock were covered by at least some grazing cattle, and so all activity areas of possums within the paddock were covered by areas where cattle foraged. However, possums avoided contact with cattle, and when some cattle were excluded from access to the part of the paddock principally used by both tuberculous and healthy possums for denning, transmission of Mycobacterium bovis from possums to these cattle ceased, although there was subsequent transmission to deer. Cattle which grazed the area used principally for possum denning continued to become infected, and these denning areas appeared to be of importance in the transmission of tuberculosis.     

Sampling rare and elusive populations

The sampling of rare and elusive populations is difficult because the costs of locating such populations are substantial and can exceed actual interviewing costs. There are efficient probability methods that have been developed recently that reduce these costs. If the special populations are geographically clustered, efficient sampling involves the rapid location of segments in which no members of the special population are located with the use of Census data, telephone screening, or incomplete lists. Populations that are not geographicaily clustered can be located by network sampling and use of large previously gathered samples. Characteristics of mobile populations such as the homeless can be estimated by capture-recapture methods.     

An improved method for measuring soil N2O fluxes using a quantum cascade laser with a dynamic chamber

A dynamic chamber method was developed to measure fluxes of N₂O from soils with greater accuracy than previously possible, through the use of a quantum cascade laser (QCL). The dynamic method was compared with the conventional static chamber method, where samples are analysed subsequently on a gas chromatograph. Results suggest that the dynamic method is capable of measuring soil N₂O fluxes with an uncertainty of typically less than 1–2 µg N₂O‐N m^?2 hour^?1 (0.24–0.48 g N₂O‐N ha^?1 day^?1), much less than the conventional static chamber method, because of the greater precision and temporal resolution of the QCL. The continuous record of N₂O and CO₂ concentration at 1 Hz during chamber closure provides an insight into the effects that enclosure time and the use of different regression methods may introduce when employed with static chamber systems similar in design. Results suggest that long enclosure times can contribute significantly to uncertainty in chamber flux measurements. Non‐linear models are less influenced by effects of long enclosure time, but even these do not always adequately describe the observed concentrations when enclosure time exceeds 10 minutes, especially with large fluxes.     

Boosting silica levels in wheat leaves reduces grazing by rabbits

Systemic application of sodium silicate can significantly enhance the levels of leaf silica in winter wheat (Triticum aestivum L. cv. Mercia), suggesting that this material could reduce the palatability of plants to vertebrate herbivores (e.g. rabbits, Oryctolagus cuniculus L.). A bioassay was developed using hydroponically grown wheat plants. Plants treated with sodium silicate were significantly more resistant to grazing by wild rabbits than untreated plants, with severe, potentially lethal feeding damage being reduced by over 50%. Further studies were carried out to develop more practical techniques for boosting silica levels in plants using silicon-rich 'fertilisers' including calcium silicate and calcium silicate slag (CSS). Silica levels were elevated in the plant 1.9-2.8 times over the control through the application of various silicon materials, in line with those of the hydroponic treatment. Encouragingly, levels of silica were elevated even in young wheat plants, which are most vulnerable to rabbit damage, and in a range of wheat varieties. The use of CSS is particularly promising because of its lower cost in comparison with calcium silicate, and it has a proven track record in slag fertilisation of rice and sugar cane crops. At the optimum CSS application rate of 3 g silicon L(-1) soil, wheat silica levels were approximately doubled, with no detrimental impacts on long-term growth or yield.