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Biomedical subjects

G C Fraser

Publications and source records attributed to G C Fraser.

50 records · Page 3Linked to original sources
PubMed1980

Seasonal availability of nematode larvae on pastures grazed by cattle in New South Wales.

Trends in the numbers of infective menatode larvae on pasture plots contaminated by cattle at different seasons of the year were defined in 3 different climatic regions. The main nematodes were Ostertagia ostertagi, Trichostrongylus spp, Haemonchus spp and Cooperia spp. On the North Coast of New South Wales with a sub-tropical climate, the numbers of infective larvae of all 4 nematodes rose rapidly to peak levels soon after each seasonal period of contamination began, then fell quickly within a few months. On the Central Coast of New South Wales, the trends were similar to those on the North Coast, except that the larvae persisted on the pasture for a much longer time. On the Northern Tablelands of New South Wales, where temperatures were much colder than on the coast, larval development was slower and major peaks of larval availability did not occur until early spring. These different seasonal trends in each region were considered to be related to the climatic differences between the regions. On pastures which were contaminated continuously, larval numbers reached maximum levels in mid-winter on the Central Coast and in early spring on the Northern Tablelands. It was concluded that the majority of these larvae were derived from the contamination of pastures in autumn and winter. Subsequently in summer, a rapid dying out of larvae was observed in all the regions, probably due to the effect of hotter weather. The studies suggest that a reduction in the contamination of pasture with nematode eggs in autumn and winter could result in pastures carrying fewer larvae and thus form the basis of effective worm control programs for cattle.

Animals↗
PubMed1980

Seasonal changes in the structure of nematode populations of cattle in New South Wales in relation to inhibited larval development.

Pasture plots in 3 climatic regions were contaminated with worm eggs of Ostertagia ostertagi, Trichostrongylus axei, Haemonchus spp and Cooperia spp in the autumn, winter and spring. Successive pairs of parasite-free calves were grazed on the plots for 7 to 10 days at 4-week intervals and then killed for worm counts 14 days after their removal from pasture. On the Northern Tablelands of New South Wales, irrespective of the season of pasture contamination, the degree of inhibition of O. ostertagi was low in winter and highest in spring. T. axei showed similar trends while Cooperia spp showed negligible inhibition. On the North Coast of New South Wales, inhibited larvae accounted for a very small proportion of the O. ostertagi burdens, while in comparison T. axei showed a much greater degree of inhibition. Larval inhibition of Haemonchus spp occurred in autumn and early winter after which it did not occur. There was negliglible inhibition in Cooperia spp. On the Central Coast of New South Wales, there was little inhibition of O. ostertagi and none in T. axei. For Haemonchus spp, inhibited larvae were found mainly in autumn and winter. The numbers of inhibited Cooperia larvae were also highest in autumn and winter and were associated with large worm burdens. The marked difference between the tablelands and coastal regions in the seasonal trends of inhibition of O. ostertagi was considered to be due to a difference in strains between the geographical regions. The possible effect of climatic factors on the inhibition-proneness of infective larvae on pasture is discussed for Ostertagia and other nematodes. The roles of host resistance and density-dependence are also discussed.

Animals↗
PubMed1979

Evaluation of an indirect fluorescent antibody test to diagnose Babesia equi infection in horses.

An indirect fluorescent antibody (IFA) test for the diagnosis of Babesia equi infections was evaluated. Antigen prepared by conventional methods was of high quality in one instance and of lesser quality in a second when possible autofluorescence of the horse blood caused inconvenience in reading tests. Tests on 14 horses shown by parasitological means to be either infected (9) or uninfected (5) produced reactions at dilutions of 1/270 to 1/7290 for infected and at 1/10 to 1/90 for uninfected animals. The accuracy of the test was further demonstrated during investigations of 701 horses in 3 states of Australia. The 30 horses reacting at 1/270 to 1/2430 were from 33 imported to 3 different farms in Australia from a common source. Investigations of crossreactivity between B. equi and B. bovis of cattle suggested that B. bovis would not interfere with the test for B. equi, but that the reverse was possible.

Animals↗
PubMed1976

The use of supplementary tests in the serological diagnosis of bovine brucellosis.

Comparative tests were carried out on serum samples using the Rose Bengal test (RBT), the complement fixation test (CFT), the antibovine globulin test (ABGT) by tube, plate and rapid variants, the mercaptoethanol test (MET) and the dithiothreitol test (DTT). Forty cows, from which Br. abortus had been recovered, gave strong reactions in all tests except for 2 cows in the SAT and 3 cows in the DTT Another group of 405 cows had not yielded Br. abortus on limited bacteriological examination. There was good correlation between the results of the CFT, RBT, tube ABGT, rapid ABGT and, to a lesser extent, the MET in cows with a CF titre greater than or equal to 16 or less than 4. In cows with CF titres of 8 the correlation was not as good while cows with a CF titre of 4 gave a wide range of reactions in these supplementary tests. A plate variant of the ABGT gave titres which were generally lower, by about 1 dilution, than those in the tube procedure. The results of the rapid ABGT correlated well with the results of the tube ABGT and the CFT in samples of high and low titre but not as well in samples of intermediate titre. The DTT gave titres which were usually lower than the corresponding MET titre. On the basis of the results obtained, tentative standards for the interpretation of the ABGT (tube) and MET were defined. It was concluded that these tests could be used to elucidate the status of a proportion of the cows which gave inconclusive results in the CFT.

Agglutination Tests↗
PubMed1976

Surgical treatment of congenital defects in the abdominal wall.

A series of 28 patients is presented with the two conditions of omphalocoele and gastroschisis treated over a five-year period . Improved survival can be obtained by the use of staged procedures with a silastic prosthesis plus intravenous alimentation with later definitive operation. If peripheral veins are used, serious complications are almost totally avoided. This combined form of therapy is the treatment of choice in infants with massive defects in the abdominal wall.

Abdominal Muscles↗
PubMed1971

Failure to thrive.

Explore the source record for details and available documents.

Congenital Abnormalities↗
PubMedDate not supplied

Encephalitis caused by a Lyssavirus in fruit bats in Australia.

This report describes the first pathologic and immunohistochemical recognition in Australia of a rabies-like disease in a native mammal, a fruit bat, the black flying fox (Pteropus alecto). A virus with close serologic and genetic relationships to members of the Lyssavirus genus of the family Rhabdoviridae was isolated in mice from the tissue homogenates of a sick juvenile animal.

Animals↗