A framework for evaluation of on-farm mastitis diagnostics in Australia

Numerous culture-based diagnostics are available on the Australian and international markets for on-farm detection of bacterial pathogens in milk. Use of such diagnostics may provide an opportunity to improve the prudent use of antimicrobials in udder health management. Farms are low-resource settings in terms of diagnostic microbiology capacity. The World Health Organisation has identified criteria for the evaluation of diagnostic tests in low resource settings based on Accuracy, Sensitivity, Specificity, User-friendliness, being Rapid or Robust, Equipment-free and being Deliverable (ASSURED). Here, we review how those criteria can be interpreted in the context of microbiological diagnosis of mastitis pathogens, and how on-farm diagnostics that are currently available in Australia perform relative to ASSURED criteria. This evaluation identifies multiple trade-offs, both with regard to scientific criteria and with regards to convenience criteria. More importantly, the purpose of testing may differ between farms, and test performance should be evaluated relative to its intended use. The ability of on-farm mastitis diagnostics to inform mastitis treatment decision-making in a timely and cost-effective manner depends not just on test characteristics but also on farm-specific pathogen prevalence, and on the farm enterprise's priorities and the farm manager's potential courses of action. With most assay evaluations to date conducted in professional laboratories, there is a surprising dearth of information on how well any of the diagnostic tests perform on-farm and, indeed, of the on-farm decision-making processes that they aim to inform.     

Serotyping of Haemophilus paragallinarum isolates from Mexico by the Kume hemagglutinin scheme

A total of 42 isolates of Haemophilus paragallinarum from Mexico were serotyped by the Kume hemagglutinin scheme. Serovars A-1, A-2, B-1, and C-2 were recognized among 11 (26.2%), 7 (16.6%), 4 (9.5%), and 14 (33.3%) isolates, respectively. A further six isolates (14.3%) showed hemagglutinating activity but could not be classified into any serovar. Commercial vaccines containing Kume serovars A-1, A-2, B-1, and C-2 may provide better protection than those bi- or trivalent infectious coryza vaccines currently used in Mexico.     

Plants as de-worming agents of livestock in the Nordic countries: historical perspective, popular beliefs and prospects for the future.

Preparations derived from plants were the original therapeutic interventions used by man to control diseases (including parasites), both within humans and livestock. Development of herbal products depended upon local botanical flora with the result that different remedies tended to develop in different parts of the world. Nevertheless, in some instances, the same or related plants were used over wide geographic regions, which also was the result of communication and/or the importation of plant material of high repute. Thus, the Nordic countries have an ancient, rich and diverse history of plant derived anthelmintic medications for human and animal use. Although some of the more commonly used herbal de-wormers were derived from imported plants, or their products, many are from endemic plants or those that thrive in the Scandinavian environment. With the advent of the modern chemotherapeutic era, and the discovery, development and marketing of a seemingly unlimited variety of highly efficacious, safe synthetic chemicals with very wide spectra of activities, herbal remedies virtually disappeared from the consciousness--at least in the Western world. This attitude is now rapidly changing. There is a widespread resurgence in natural product medication, driven by major threats posed by multi-resistant pest, or disease, organisms and the diminishing public perceptions that synthetic chemicals are the panacea to health and disease control. This review attempts to provide a comprehensive account of the depth of historical Nordic information available on herbal de-wormers, with emphasis on livestock and to provide some insights on potentially rewarding areas of "re-discovery" and scientific evaluation in this field.     

Are Endocrine Disrupting Compounds a Threat to Farm Animal Health,Welfare and Productivity?

Contents The sources and characteristics of endocrine disrupting compounds (EDCs) are reviewed and discussed with respect to their potential effects on farm animal health, welfare and productivity. The importance of certain properties of these compounds in relation to the expression of their biological effects is addressed together with potential routes of exposure. It is concluded that little is known of factors affecting the tissue concentrations of EDCs in farm animals, the concentrations that are required to perturb physiological function in these species, the effects of prolonged exposure to low doses, the effect of cocktails of EDCs and other pollutants or the responses of specific organs and physiological systems that are affected by EDCs. Much of the available information pertaining to EDCs is derived from epidemiological studies of wildlife species and from laboratory animal studies and while these studies have significant limitations, they are considered to be valuable indicators of potential effects in farm animal species. The results of such studies, together with the small amounts of data from studies of ruminants, indicate that there may be significant effects of exposure to environmental levels of EDCs on farm animal health, even although effects are not generally apparent in practice, at this time.     

Characterization of,and immune responses of mice to,the purified OmpA-equivalent outer membrane protein of Pasteurella multocida serotype A:3 (Omp28)

Pasteurella multocida A:3 is a major cause of bovine pneumonia. A major antigenic heat-modifiable 28kDa outer membrane protein (Omp28) was previously identified. The purpose of this study was to purify and characterize Omp28 immunologically and structurally. Omp28 was extracted from N-lauroylsarcosine-insoluble protein preparations by a combination of detergent fractionation with Zwittergent 3-14 and chromatography. Partial N-terminal amino acid sequence confirmed Omp28 as a member of the OmpA-porin family. However, porin activity could not be demonstrated in a lipid-bilayer assay. Heat modifiability of purified Omp28 was demonstrated, and Omp28 was found in outer membrane fraction of P. multocida. Surface exposure of Omp28 was demonstrated by partial protease digestion of intact bacteria, by binding of anti-Omp28 polyclonal ascites fluid to the bacterial surface, and by partial inhibition of anti-outer membrane antiserum binding by previous incubation of the bacteria with anti-Omp28 serum. CD-1 mice vaccinated with purified Omp28 developed a significant antibody titer (P<0.05) compared to the control treatment group but were not protected from a homologous intraperitoneal bacterial challenge. By contrast, treatment groups vaccinated with P. multocida outer membrane, formalin-killed P. multocida or a commercial vaccine were significantly protected from challenge. In vitro complement-mediated killing of P. multocida was observed in post-vaccination sera of outer membrane, formalin-killed P. multocida, and commercial vaccine-treatment groups, but not with sera from the Omp28-treatment group. In conclusion, although Omp28 is surface exposed and antigenic, it may not be a desirable immunogen for stimulating immunity to P. multocida.     

Single primer polymerase chain reaction fingerprinting for Pasteurella multocida isolates from laboratory rabbits

OBJECTIVE: To evaluate a rapid polymerase chain reaction (PCR) fingerprinting technique for discriminating among Pasteurella multocida isolates from laboratory rabbits. SAMPLE POPULATION: 33 P multocida isolates from rabbits with clinical pasteurellosis. PROCEDURE: PCR assays were conducted with 2 minisatellites (core sequence and modified core sequence of phage M13) and 2 microsatellites ([GTG]5 and [GACA]4). Each bacterium was assigned to a PCR type for each of the primers used. Boiled bacterial extracts and purified genomic DNA were compared by use of PCR assays for phage M13 and (GACA)4. Plasmids were isolated from each bacterium, and their influence on PCR fingerprint was determined, using boiled extracts as a DNA source. RESULTS: M13 core sequence and M13 modified core sequence yielded 5 and 8 PCR types, respectively. The microsatellites (GTG)5 and (GACA)4 yielded 4 and 9 PCR fingerprint types, respectively. Fingerprint patterns obtained by use of isolated DNA differed from those obtained by use of boiled extracts, although discrimination among P multocida isolates was similar. The presence or absence of plasmids did not affect PCR fingerprints. CONCLUSION: Single primer PCR fingerprinting with minisatellite and microsatellite primers is an efficient and reproducible method for the discrimination of P multocida isolates from rabbits and can be performed directly, using boiled bacterial extracts as a source of template, although more bands were obtained from pure genomic DNA.     

Comparative Expression Analysis of Gametogenesis‐Associated Genes in Foetal and Adult Bubaline (Bubalus bubalis) Ovaries and Testes

This study was conducted to identify and analyse the expression of gametogenesis‐associated genes and proteins in foetal and adult buffalo gonads of both the sexes. Relative quantification of the genes was determined by qPCR and Western blotting. Immunohistochemistry was also performed for various gametogenesis‐associated proteins in foetal and adult gonads of both the sexes. We observed significantly (p < 0.05) increased expression of primordial germ cell‐specific, meiotic as well as genes associated with oocyte maturation and development in foetal ovaries as compared to the adult ones. However, significantly (p < 0.05) increased expression of proteins associated with oocyte maturation like GDF9 and ZP4 was found in adult ovaries, indicating temporal regulation of mRNA translation during oogenesis. Meiotic genes showed significantly (p < 0.05) increased expression in adult testes as compared to foetal testes and ovaries, indicating onset of meiosis at a later stage in spermatogenesis. In general, the expression of primordial germ cell‐associated as well as meiotic genes was higher in adult testes, indicating the increased biological activity in the organ. Immunohistochemistry revealed localized expression of gametogenesis‐associated proteins in ovarian follicles and seminiferous tubules of testes, while the surrounding somatic tissues were devoid of these proteins. The study gives an understanding of the sequential and temporal events of gene expression as well as mRNA translation during male and female gametogenesis. It could also be concluded that follicles and seminiferous tubules are the functional units of the female and male gonads, respectively, and their function could be enhanced by appropriate chemical and genetic intervention of the somatic tissue immediately surrounding them. This assumes importance in the context that buffalo attains sexual maturity at an older age of 2–3 years and have smaller ovaries with lesser number of primordial follicles in comparison with cattle, which is suggested to be the main reason of their poor breeding performance.     

A Chemoautotrophically Based Cave Ecosystem

Microbial mats discovered in a ground-water ecosystem in southern Romania contain chemoautotrophic bacteria that fix inorganic carbon, using hydrogen sulfide as an energy source. Analysis of stable carbon and nitrogen isotopes showed that this chemoautotrophic production is the food base for 48 species of cave-adapted terrestrial and aquatic invertebrates, 33 of which are endemic to this ecosystem. This is the only cave ecosystem known to be supported by in situ autotrophic production, and it contains the only terrestrial community known to be chemoautotrophically based.