Frequency of equine laminitis: a systematic review with quality appraisal of published evidence

Equine laminitis is a highly debilitating disease of the foot. Despite its perceived importance, epidemiological characteristics are poorly understood and the true frequency of the disease remains unclear. The objective of this study was to retrospectively assess previous research to identify publications which provide the best evidence of the frequency of naturally-occurring equine laminitis. A systematic review of English language publications was conducted using MEDLINE (1950–2010), CAB Direct (1910–2010) and IVIS (1997–2010). Additional publications were included by searching bibliographies. Search terms included laminitis, equine, frequency, prevalence and incidence. Studies that allowed frequency estimations to be made for naturally-occurring equine laminitis were included. Information was extracted using predefined data fields, including 13 study quality indicators.Sixty-nine publications were appraised. Ten were considered to provide the most reliable information, estimating the frequency of equine laminitis ranging from 1.5% to 34%. Previous publications estimating laminitis frequency were generally poor quality. Laminitis frequency varied across publications however the publications included in this review focussed on many of the different underlying laminitis aetiologies and comparison of the frequencies between groups would be inappropriate. High-quality evidence-based studies are needed to estimate the true disease frequency in different equine populations.     

Enterovirulence of enterotoxigenic Bacteroides fragilis in gnotobiotic pigs.

A porcine isolate of enterotoxigenic Bacteroides fragilis colonized the intestinal tract and caused watery, nonhemorrhagic diarrhea when given orally to 12, 1- to 2-day-old gnotobiotic pigs. Diarrhea occurred 2 to 3 days post-inoculation and continued throughout the 4 to 6 day post-inoculation period. Diarrheic pigs became mildly anorexic and dehydrated. They developed intestinal lesions characterized by swelling, vacuolation, and exfoliation of enterocytes, and crypt hyperplasia throughout the large intestine and, to a lesser extent, in the distal small intestine. Bacterial adherence to, or invasion of, the intestinal mucosa was not detected. A porcine isolate of nonenterotoxigenic B. fragilis was administered orally to six control pigs. The isolate colonized the intestinal tract, but the pigs did not develop clinical disease or intestinal lesions. The pathogenetic mechanism of the disease may involve mediation by a soluble enterotoxin (or toxins) elaborated by B. fragilis.     

Strong resistance to phosphine in the rusty grain beetle,Cryptolestes ferrugineus (Stephens) (Coleoptera: Laemophloeidae): its characterisation,a rapid assay for diagnosis and its distribution in Australia

BACKGROUND: The recent development of very high resistance to phosphine in rusty grain beetle, Cryptolestes ferrugineus (Stephens), seriously threatens stored‐grain biosecurity. The aim was to characterise this resistance, to develop a rapid bioassay for its diagnosis to support pest management and to document the distribution of resistance in Australia in 2007–2011. RESULTS: Bioassays of purified laboratory reference strains and field‐collected samples revealed three phenotypes: susceptible, weakly resistant and strongly resistant. With resistance factors of > 1000 × , resistance to phosphine expressed by the strong resistance phenotype was higher than reported for any stored‐product insect species. The new time‐to‐knockdown assay rapidly and accurately diagnosed each resistance phenotype within 6 h. Although less frequent in western Australia, weak resistance was detected throughout all grain production regions. Strong resistance occurred predominantly in central storages in eastern Australia. CONCLUSION: Resistance to phosphine in the rusty grain beetle is expressed through two identifiable phenotypes: weak and strong. Strong resistance requires urgent changes to current fumigation dosages. The development of a rapid assay for diagnosis of resistance enables the provision of same‐day advice to expedite resistance management decisions. © 2012 Commonwealth of Australia. Published by John Wiley & Sons, Ltd.     

Dendritic cells in cattle: phenotype and function

Dendritic cells are professional antigen presenting cells derived from the bone marrow and distributed throughout body tissues where they are located in sites that are suitable for antigen uptake. They are central to the induction of immune responses in naive animals and thus have become targets in strategies that are aimed at modulating resistance to infection. Studies in cattle have shown that the dendritic cells are phenotypically heterogeneous and that the different phenotypes have different biological properties. The molecular basis for this variation has begun to be investigated and has led to the identification of a member of the SIRPalpha family of signal regulatory proteins (MyD1) on a subset of dendritic cells in afferent lymph. Uptake of antigen by cattle dendritic cells is by a number of mechanisms that can involve endocytosis via clathrin coated pits or via caveolae as well as macropinocytosis.     

Analyses of genes encoding Theileria parva p104 and polymorphic immunodominant molecule (PIM) reveal evidence of the presence of cattle-type alleles in the South African T. parva population

Restriction fragment length polymorphism analysis of PCR products (PCR-RFLP) and sequencing of the variable region of the p104 and PIM genes was performed on samples obtained from South African T. parva parasites originating from cattle on farms with suspected theileriosis and from buffalo. p104 and PIM PCR-RFLP profiles similar to those of the T. parva Muguga stock, an isolate that causes ECF in Kenya, were obtained from three of seven cattle samples collected on a farm near Ladysmith in KwaZulu-Natal Province. Amino acid sequences of the p104 and PIM genes from two of these samples were almost identical to the T. parva Muguga p104 and PIM sequences. This result supports findings from a recent p67 study in which p67 alleles similar to those of the T. parva Muguga stock were identified from the same samples. While these results suggest the presence of a cattle-derived T. parva parasite, reports of cattle-to-cattle transmission could not be substantiated and ECF was not diagnosed on this farm. Although extensive diversity of p104 and PIM gene sequences from South African T. parva isolates was demonstrated, no sequences identical to known cattle-type p104 and PIM alleles were identified from any of the buffalo T. parva samples analyzed. 'Mixed' PIM alleles containing both cattle- and buffalo-type amino acid motifs were identified for the first time, and there appeared to be selection of cattle-type and 'mixed'-type PIM sequences in the cattle samples examined.     

Metabolism of bromoxynil octanoate in growing wheat

[¹⁴C]ring-Bromoxynil octanoate was applied to the leaves of wheat seedlings, which were cultivated in a growth cabinet under controlled conditions for 14 days. Fractionation of the metabolites present in the treated leaves, which accounted for about 63% of the radioactivity applied, indicated a complex metabolic pathway resulting from initial hydrolysis to free bromoxynil, followed by three consecutive or concurrent steps (a) hydrolysis of the cyano group to the amide and carboxylic acid, followed by decarboxylation to 2,6-dibromophenol (0.5% of the ¹⁴C applied), (b) replacement of one or both bromine atoms by hydroxy groups to 3-bromo-4,5-dihydroxybenzonitrile (1.3 %) and 3,4,5-trihydroxybenzo-nitrile (0.6 %) or their hydrolysis products, (c) replacement of one or both bromine atoms by hydrogen, giving 3-bromo-4-hydroxybenzonitrile (1.9 %) and 4-hydroxy-benzonitrile (0.6%) or their hydrolysis products. Some of the phenolic acids or phenols formed are natural plant constituents. The metabolites identified represented in all about 11 % of the herbicide applied, but no individual metabolite accounted for more than a small proportion of it.     

Determination of the efficacy of pyrantel pamoate at the therapeutic dose rate against the tapeworm Anoplocephala perfoliata in equids using a modification of the critical test method

A total of 59 equids (54 horses and five Shetland ponies) were treated with pyrantel pamoate once, at the dose rate of approximately 6.6 mg base kg-1, during the period November 1985-January 1988. The drug was administered as a paste formulation (51 equids) intraorally or as a suspension formulation by stomach tube (eight equids). The purpose of treatment was to evaluate the activity of pyrantel pamoate (at the therapeutic dose rate) for removal of the tapeworm, Anoplocephala perfoliata, by a modified (24-h) critical test. The presence or absence of tapeworms was not determined for the equids before treatment. Twenty-three (39%) of the 59 treated equids were found to be infected with A. perfoliata (from one to 180 specimens per infected equid) at necropsy. Removals varied from 67 to 100% (average 88%) for the 18 infected equids treated with the paste formulation. For the five infected equids treated with the suspension, removals were 58-100% (average 75%). The combined average removal of A. perfoliata for both formulations was 87%. Two abnormal (triradiate) specimens of A. perfoliata were recovered; one from each of two different equids.     

Multiple hereditary ocular anomalies in a herd of cattle

A Brahman x Santa Gertrudis herd of cows bred to a Hereford bull was evaluated because of a 3-year history of several calves born with congenital blindness. Multiple congenital ocular anomalies in 2 calves included microphthalmos, microcornea, microcoria, heterochromia iridis, microlentia, cataracts, retinal dysplasia, retinal detachment, anterior segment dysgenesis, acorea, and proliferation of the anterior neuroectoderm. On the basis of the lack of environmental factors and persistence of an intermittent problem when breeding to a single bull, a genetic defect was diagnosed as the probable cause. Dominant inheritance with varied expressivity may have best explained the lack of obvious signs in the bull, with emergence of various anterior and posterior segment defects in offspring from unrelated cows.