The Complement Fixation Test For brucella Ovis

Abstract

Extract

Sir, — Correspondence in your journal has indicated that there is some divergence of opinion about the efficacy of the complement fixation (CF) test for the diagnosis of ovine brucellosis (Brucella ovis) ⁽¹⁾ Hicks, J. D., Burr, G. R., Marshall, D. R. and Vidier, B. M. 1978. CFT inaccurate for epididymitis. N.Z. vet. J., 24: 34–34.  [Google Scholar] ⁽²⁾ Bruére, A. N. and West, D. M. 1978. CFT inaccurate for epididymitis. N.Z. vet. J., 26: 115–115. [Taylor &; Francis Online] , [Google Scholar] ⁽³⁾ O'Hara, P. J., Anderson, L. D. and Weddell, W. 1978. N.Z. vet. J. CFT inaccurate for epididymitis, 26: 115–116. [Taylor &; Francis Online] , [Google Scholar] ⁽⁴⁾ Hicks, J. D., Burr, G. R. and Marshall, D. R. and. 1978. CFT inaccurate for epididymitis. N.Z. vet. J., 26: 135–135. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]. A number of letters which have recently been received at the Animal Health Reference Laboratory indicate that this issue is not yet fully resolved. We believe that part of the difficulty is due to misunderstanding about the use and interpretation of the test, and we would therefore like to comment.     

Serology as an aid to diagnosis: uses and abuses

The importance of correct interpretation of serological test results, common sources of error and problems associated with tests are discussed. In bovine brucellosis, a disease which is ideally suited to serological diagnosis, foetal contact with infection may cause the calf to be a serologically negative carrier. The immune tolerant animal resulting from foetal contact with virus is a major problem in the serological detection of border disease. In Johnes' disease and to a lesser extent in Brucella ovis and leptospiral infections, problems associated with sensitivity and specificity of the tests are stressed. Serovar specificity, cumbersome test procedures and negative tests in the incubation period cause difficulty in the interpretation of serological test results for leptospirosis. The importance of clinical examination, herd histories and alternative diagnostic procedures is important in all diseases. Wherever possible, flocks or herds should be maintained in specific disease-free state. Selection of stock from accredited herds or flocks is the most certain method of Guying non-infected animals.     

A long-snouted predatory dinosaur from africa and the evolution of spinosaurids

Fossils discovered in Lower Cretaceous (Aptian) rocks in the Tenere Desert of central Niger provide new information about spinosaurids, a peculiar group of piscivorous theropod dinosaurs. The remains, which represent a new genus and species, reveal the extreme elongation and transverse compression of the spinosaurid snout. The postcranial bones include blade-shaped vertebral spines that form a low sail over the hips. Phylogenetic analysis suggests that the enlarged thumb claw and robust forelimb evolved during the Jurassic, before the elongated snout and other fish-eating adaptations in the skull. The close phylogenetic relationship between the new African spinosaurid and Baryonyx from Europe provides evidence of dispersal across the Tethys seaway during the Early Cretaceous.     

Hunting behavior of a marine mammal beneath the antarctic fast Ice

The hunting behavior of a marine mammal was studied beneath the Antarctic fast ice with an animal-borne video system and data recorder. Weddell seals stalked large Antarctic cod and the smaller subice fish Pagothenia borchgrevinki, often with the under-ice surface for backlighting, which implies that vision is important for hunting. They approached to within centimeters of cod without startling the fish. Seals flushed P. borchgrevinki by blowing air into subice crevices or pursued them into the platelet ice. These observations highlight the broad range of insights that are possible with simultaneous recordings of video, audio, three-dimensional dive paths, and locomotor effort.     

β-Methoxyacrylates; synthesis of new types of strobilurin fungicides with extended side chains

A series of novel oxime ether β-methoxyacrylates have shown good fungicidal activity against a number of fungal pathogens. These were designed by introducing a one- or two-atom spacer group adjacent to the oxime ether group. Best fungicidal activity was obtained when an amino spacer group was used. ©1999 Society of Chemical Industry     

Tracking the long-term decline and recovery of an isolated population

Effects of small population size and reduced genetic variation on the viability of wild animal populations remain controversial. During a 35-year study of a remnant population of greater prairie chickens, population size decreased from 2000 individuals in 1962 to fewer than 50 by 1994. Concurrently, both fitness, as measured by fertility and hatching rates of eggs, and genetic diversity declined significantly. Conservation measures initiated in 1992 with translocations of birds from large, genetically diverse populations restored egg viability. Thus, sufficient genetic resources appear to be critical for maintaining populations of greater prairie chickens.     

A review of thermal stress in cattle

Cattle control body temperature in a narrow range over varying climatic conditions. Endogenous body heat is generated by metabolism, digestion and activity. Radiation is the primary external source of heat transfer into the body of cattle. Cattle homeothermy uses behavioural and physiological controls to manage radiation, convection, conduction, and evaporative exchange of heat between the body and the environment, noting that evaporative mechanisms almost exclusively transfer body heat to the environment. Cattle control radiation by shade seeking (hot) and shelter (cold) and by huddling or standing further apart, noting there are intrinsic breed and age differences in radiative transfer potential. The temperature gradient between the skin and the external environment and wind speed (convection) determines heat transfer by these means. Cattle control these mechanisms by managing blood flow to the periphery (physiology), by shelter-seeking and standing/lying activity in the short term (behaviourally) and by modifying their coats and adjusting their metabolic rates in the longer term (acclimatisation). Evaporative heat loss in cattle is primarily from sweating, with some respiratory contribution, and is the primary mechanism for dissipating excess heat when environmental temperatures exceed skin temperature (~36°C). Cattle tend to be better adapted to cooler rather than hotter external conditions, with Bos indicus breeds more adapted to hotter conditions than Bos taurus. Management can minimise the risk of thermal stress by ensuring appropriate breeds of suitably acclimatised cattle, at appropriate stocking densities, fed appropriate diets (and water), and with access to suitable shelter and ventilation are better suited to their expected farm environment.