Future options for brucellosis surveillance in New Zealand beef herds

It is probable that bovine brucellosis will be eradicated from New Zealand by 1990. However, continued surveillance for the disease will have to be maintained for a number of years. This paper examines alternative methods of surveillance in beef herds with a view to ensuring that the most cost effective method is used. The three surveillance methods examined are the present automated complement fixation test, abattoir surveillance, and a system based on a delayed hypersensitivity skin test using a purified Brucella protein antigen. It is concluded that despite the relatively low sensitivity of the skin test the probability of its identifying herds as infected is likely to be greater in practice than abattoir surveillance. The skin test is cheaper than the present complement fixation test.     

An outbreak of malignant catarrhal fever in Père David's deer (Elaphurus davidianus)

Thirteen (54%) of 24 Père David's deer (Eluphurus duvidianus) imported from England died of malignant catarrhal fever (MCF) within a year of arrival at Invermay Agricultural Centre. The duration of clinical illness was from one to approximately 33 days, and the most common clinical signs were depression, a hunched stance and diarrhoea. On post-mortem examination, most deer showed recent localised haemorrhages, often into the large intestine. In all deer there was histological vasculitis especially in the brain.     

Blood thiamine levels in normal cattle and sheep at pasture

Analysis of whole blood samples from 174 cattle and, 174 sheep from 3 geographical regions of New Zealand over a 10 month period showed a mean (range) thiamine level of 122 nmol/l (71-237 nmol/l) for cattle and 118 nmol/l (67-227 nmol/l) for sheep. Regional and seasonal differences were noted with levels tending to rise over the summer period. A reference range of 75-185 nmol/l is proposed for both cattle and sheep to cover these variations. Levels below 50 nmol/l are considered indicative of deficiency.     

The detection of Mycobacterium paratuberculosis in bovine faeces by isolation and the comparison of isolation with the examination of stained smears by light microscopy

The detection of Mycobacterium paratuberculosis organisms in bovine faeces by isolation was compared with that by the microscopical examination of Ziehl-Neelsen stained faecal smears for the presence of clumps of acid-fast M. paratuberculosis organisms. Faeces were obtained from cattle naturally or experimentally infected with M. paratuberculosis as well as from uninfected cattle. Microscopical examination was an unreliable method for the detection of M. paratuberculosis organisms, since the organisms were only detected in 99 (=55.9%) of 177 culturally positive faecal samples. 1111 addition, clumps of acid-fast organisms indistinguishable from M. paratuberculosis were also observed iin three of 18 samples from cattle free from Johne's disease and in 18 of 37 culturally negative samples from paratuberculous cattle. When M. paratuberculosis organisms were added to faeces from an uninfected cow, results showed that isolation attempts should be positive when 15 or more M. paratuberculosis organisms per gram of faeces are present.     

Platelet activating factor as a mediator of equine cell locomotion

Equine polymorphonuclear (PMN) and mononuclear (MN) leucocytes were separated on Percoll gradients and used to study the chemoattractant properties of the polar ether-linked phospholipid, platelet activating factor (PAF). Six concentrations of PAF ranging from 1 ng/ml to 100 g/ml were studied in each of two in vitro assay systems, the agarose microdroplet and a microfilter technique. Very significant (p<0.01) increases in the movement of both PMN and MN cells were obtained with most concentrations of PAF. In two instances there was no apparent concentration-response relationship, although the action of PAF was approximately bell-shaped in two others. The possible significance of these findings for equine inflammatory conditions is discussed.     

Releases in israel ofAphelinus perpallidus,a recently introduced parasite of the pecan blackmargined aphid,Monellia caryella

Six shipments totaling 3452 mummies of the blackmargined aphid,Monellia caryella (Fitch), parasitized withAphelinus perpallidus Gahan, were obtained by air freight during the years 1982-1985 from Texas A&M Research Center, El Paso, Texas. About two-thirds of the mummies did not yield parasites. A colony ofA. perpallidus was established in the laboratory. Under laboratory conditions the percentage of emerged parasites was higher than that in the imported mummies, and the parasite had very limited impact on the aphid population. Field releases of the parasite were made but no establishment ofA. perpallidus was observed through the years.