Production of eosinophil chemoattractant activity by ovine gastrointestinal nematodes

Eosinophilia is a well documented feature of helminth infections but the precise nature of the interaction between parasite and eosinophil remains an enigma. This paper describes experiments demonstrating that ruminant gastrointestinal trichostrongyles produce potent chemoattractant activity for ovine bone marrow-derived eosinophils in vitro. This activity was initially identified as a constituent of whole worm extracts of third and fourth larval (L3, L4), and adult stages of Teladorsagia circumcincta, and adult Haemonchus contortus. Similar activity was detected in excretory/secretory (E/S) material derived from live T. circumcincta L3. Subsequently, by adapting the assay technique to incorporate live worms directly into the system, it was shown that L3 of both T. circumcincta and H. contortus produced eosinophil chemoattractant activity. In contrast, neither whole worm extracts, or E/S preparations from mixed stages of the free-living nematode Caenorhabditis elegans contained eosinophil chemoattractant activity, and there was no evidence of chemoattractant production by live C. elegans. The results described are challenging to the traditional dogma that eosinophils are host-protective effector cells, and raise the intriguing possibility that ovine nematodes actively encourage recruitment of eosinophils. Local eosinophil-mediated mucosal damage, comparable to that seen in the asthmatic lung, may then provide a permissive local microenvironment for the parasite. Moreover, if they prove important for pathogenicity, nematode chemoattractants could offer future potential as novel therapeutic targets.     

The effects of ractopamine hydrochloride on lean carcass yields and pork quality characteristics

One hundred eighty barrows were evaluated to determine the effects of ractopamine hydrochloride (RAC) on lean carcass yields and pork quality. The pens were blocked by weight (six pens per block) with starting block weights of 69.0, 70.7, 73.8, 76.6, 78.4, and 84.3 kg. Pens within a block were assigned randomly to one of three RAC treatments so each treatment in a block was replicated twice. Treatments (as-fed basis) included control diet, 10 ppm of RAC added (R10), and 20 ppm of RAC added (R20) and ranged from 25 to 41 d depending on block. Pigs were slaughtered by blocks when block average live weights were 109 kg. Gain and feed efficiency were improved (P < 0.05) with increasing dietary concentrations of RAC, but feed intake did not differ (P > 0.05). Dressing percentage was higher (P < 0.05) for RAC-treated pigs. Subjective color, firmness, marbling scores, and Minolta L* reflection of the LM were not different (P > 0.05) among treatments. Carcass weights were heavier (P < 0.05) for pigs treated with RAC compared with control pigs and were higher for R20 than for R10. The RAC-fed pigs had greater (P < 0.05) yields (actual and percentage of HCW) of the following Institutional Meat Purchase Specification (IMPS) cuts than control pigs: trimmed, boneless ham (IMPS-402C and IMPS-402G), loin (IMPS-414), sirloin, and Boston butt (IMPS-406A). Pigs treated with RAC had a greater (P < 0.05) percentage of fat-free lean trimmings (IMPS-418) than did control pigs. Pigs treated with the R20 concentration had increased (P < 0.05) water-holding capacity compared with control pigs. Purge loss decreased linearly (P < 0.05) with increasing RAC compared with control for 14-d aged, non-enhanced loins. Warner-Bratzler shear (WBS) force values measured for nonenhanced chops were greater for RAC-treated pigs than for control pigs with a low dose response (P = 0.001). Enhanced chop (salt and phosphate injection) WBS values did not differ (P > 0.05) among dietary treatments. Trained sensory evaluation panel results for tenderness decreased in a low-dose plateau response fashion for nonenhanced chops (P = 0.004). Tenderness of enhanced chops decreased linearly (P = 0.04) with increasing RAC concentrations. No differences (P > 0.05) were found in juiciness or flavor of enhanced or nonenhanced chops. Feeding RAC to late-finishing swine resulted in faster growing, more efficient animals with increased boneless subprimal yields, and it had little effect on pork juiciness and flavor.     

Bacterial culture of blood from critically ill dogs and cats: 100 cases (1985-1987)

Of 100 critically ill dogs and cats, 49 (39 dogs, 10 cats) had bacteremia. Gram-negative bacilli were the most common isolates from the bloodstream of dogs with bacteremia (46%), and gram-positive cocci and anaerobic bacteria were isolated from 36% and 31% of positive cultures, respectively; 15% of positive cultures were polymicrobial. In cats, gram-negative bacilli (especially Salmonella enteritidis) and anaerobic bacteria were the most common isolates, and 30% of positive cultures were polymicrobial. Gram-positive cocci were not isolated from the blood-stream of cats. Odds ratios, adjusted for the combined effects of disease status (severe vs nonsevere), results of bacterial culture of blood result (positive vs negative), and species (dog vs cat) were calculated for mortality in animals in the study. In animals with bacteremia, severe disease increased the risk of death 11.6-fold, compared with the risk in animals with nonsevere disease. Bacteremia increased mortality 10-fold in animals with severe disease, compared with mortality in animals with severe disease without bacteremia. Animals with severe disease and bacteremia were 15.6 times more likely to die than were those with nonsevere disease and negative culture results. In animals with nonsevere disease, culture results (positive vs negative) were not related significantly to mortality. Disease status (severe vs nonsevere) in animals without bacteremia also was not significantly related to mortality. There was no significant difference in overall mortality in dogs, compared with that in cats.(ABSTRACT TRUNCATED AT 250 WORDS)     

Seasonal effects on the aerobic bacterial and fungal conjunctival flora of normal thoroughbred brood mares in Florida

Objective To evaluate seasonal effects on the presence or absence of fungal and aerobic bacterial flora of the conjunctival fornix of normal Florida Thoroughbred horses. Sample population Both eyes of 100 horses. Procedure Horses with normal anterior segment ophthalmic examinations from three farms in north central Florida were included. Each animal had the ventral conjunctival fornix of each eye swabbed with sterile culturettes. Samples were taken in October, January, April, and July (1999–2000). Aerobic and fungal cultures were plated. Bacterial cultures were reviewed at 24 and 48 h. Fungal cultures were reviewed weekly for 4 weeks. Logistic regression analysis with season as a factor and age of the horse as a covariate was performed. Statistical significance was set at P < 0.01. Results Horses ranged from 3 to 24 years of age, with a median age of 9 years. Twenty‐four genera of bacteria and 35 genera of fungi were recovered. Corynebacterium sp., Staphylococcus sp., Bacillus sp. and Moraxella sp. were the bacteria most frequently isolated. Mold species, dematiaceous mold species, Chrysosporium sp., Cladosporium sp., and Aspergillus sp. were the most frequently recovered fungi. Season did not have a significant effect on the presence of microorganisms isolated for individual horses adjusted for age. Younger horses had an increased incidence of gram‐negative rods and fungal isolates. The number of bacteria and fungi isolated are not uniform across seasons. Conclusion There were no significant differences between the number or type of organisms cultured during the sampling seasons in normal Florida horses. A large range of normal bacterial and fungal flora were isolated from these horses. The number of bacteria and fungi isolated are not uniform across seasons. The likelihood of detecting an organism depends on the horses’ age.     

The amended insulin to glucose ratio and diagnosis of insulinoma in dogs

Amended insulin to glucose ratios were calculated from the concentrations of serum insulin and blood glucose measured concurrently during either a glucagon tolerance test or after feeding in healthy dogs. Values greater than 30 𝛍U/mg which are supportive of a diagnosis of insulinoma were obtained at certain times during the test period. Amended insulin to glucose ratios calculated from serum insulin and blood glucose concentrations obtained during a glucagon tolerance test and an oral glucose tolerance test on a dog with an insulinoma were less than 30 𝛍U/mg, or equivocal, at different times during the test period. This indicates that under some circumstances healthy dogs may have elevated amended insulin to glucose ratios, and dogs with insulinoma may have a normal amended insulin to glucose ratio. Care is essential for interpretation of amended insulin to glucose ratios, and a diagnosis of insulinoma using the ratio must be made in conjunction with appropriate clinical signs of hvnoglvcaemia.     

Infectious bursal disease serology in New Zealand poultry flocks

Extract

Madam:– Infectious bursal disease (IBD) is recognised as a serious economically significant disease of poultry. N.H. Christensen in his letter to your Journal (1) has summarised the ways in which IBD causes such economic loss.     

Viral respiratory diseases (ILT,aMPV infections,IB): are they ever under control?

Abstract1.?The use of vaccines is the main approach to control of the economically important poultry viral respiratory diseases infectious laryngotracheitis (ILT), avian metapneumovirus (aMPV) infections and infectious bronchitis (IB). This paper appraises the current methods of vaccine control in the light of the nature of each virus and epidemiological factors associated with each disease.

2.?Infectious laryngotracheitis virus (ILTV) exists as a single type with a wide range of disease severity. It is a serious disease in certain regions of the world. Recent work has distinguished molecular differences between vaccine and field strains and vaccine virus can be a cause of disease. Vaccines have remained unaltered for many years but new ones are being developed to counter vaccine side effects and reversion and reactivation of latent virus.

3.?Avian metapneumoviruses, the cause of turkey rhinotracheitis and respiratory disease in chickens exists as 4 subtypes, A, B, C and D. A and B are widespread and vaccines work well provided that accurate doses are given. Newer vaccine developments are designed to eliminate reversion and possibly counter the appearance of newer field strains which may break through established vaccine coverage.

4.?IB presents the biggest problem of the three. Being an unstable RNA virus, part of the viral genome that codes for the S1 spike gene can undergo mutation and recombination so that important antigenic variants can appear irregularly which may evade existing vaccine protection. While conventional vaccines work well against homologous types, new strategies are needed to counter this instability. Molecular approaches involving tailoring viruses to suit field challenges are in progress. However, the simple use of two genetically different vaccines to protect against a wide range of heterologous types is now a widespread practice that is very effective.

5.?None of the three diseases described can claim to be satisfactorily controlled and it remains to be seen whether the newer generations of vaccines will be more efficacious and cost effective. The importance of constant surveillance is emphasised and the testing of novel vaccines cannot be achieved without the use of vaccine-challenge experiments in poultry.