The intensity of resistance by mature Merino ewes against Haemonchus contortus and Tichostrongylus colubriformis in single-species and combined-species infection

Three-year-old, non-lactating and non-pregnant Merino ewes, raised on pasture under a program of strategic treatment with anthelmintic and found to be extremely resistant to "trickle" infection with Haemonchus contortus, were given single-dose infections with either H. contortus or Trichostrongylus colubriformis or both species together. The purpose was to ascertain the intensity of protective immunity against the 2 parasites in sheep with immunity acquired from a presumably slight exposure to infection. To provide a criterion, some infected ewes were immunosuppressed with corticosteroid, dexamethasone. Untreated ewes were extremely resistant to challenge infection with either 15,000 or 150,000 H. contortus or 15,000 T. colubriformis. Surprisingly, when mixed infection was given, egg counts for H. contortus were significantly elevated compared with infection by that species alone. Antibody to antigens from infective larval and adult H. contortus was measured in serum by enzyme-linked-immunosorbent assay (ELISA) during the course of infection. Serum titres against larval antigens were significantly depressed when infections with either H. contortus or T. colubriformis were permitted by immunosuppression with dexamethasone, whereas those against adult antigen were depressed when infection with T. colubriformis was permitted.     

疑似碘酊致牛死亡一例

笔者在临床上曾遇到一疑似“碘酊”致牛死亡的病例,由于未曾见过碘酊致牛死亡的报道,查阅资料也终未得到答案.笔者将其整理如下,供同行探讨。     

Observations on pathogenic organisms in the airborne state

Summary Increasing numbers of human and animal diseases have been shown to be disseminated by micro-organisms in aerial suspension. The viability of such airborne organisms declines progressively as the result of physical and other factors which are summarized in the text. Relative humidity strongly influenced viability in experimental studies, but strain differences also appear to play an important role in certain diseases. Laboratory results were confirmed by observations made in the field on poliomyelitis, smallpox, foot and mouth disease, rinderpest and Newcastle disease; it is probable that Marek's disease, avian infectious bronchitis and numerous other maladies spread in the same manner. Long range dissemination by airstreams may be influenced, to some extent, by the virulence of the causal agent and by the fall-out rate for particles of a size which is optimal for deposition at the predilection site of the specific organism. Furthermore, local geographical and climatic factors may greatly modify distributional patterns of airborne disease during major epidemics or epizootics: specific outbreaks are cited as examples.

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Sumario Se ha demostrado que un número criente de enfermedades tanto en el hombre como en los animales son diseminadas por micro-organismos que se encuentran en suspension en el aire. La viabilidad de tales micro-organismos en el aire declina en forma progresiva como resultado de factores fisicos y otros factores sumarizados en el texto. La humedad relativa influencia de manera especial la viabilidad en estudios experimentales, pero las diferencias entre las cepas tambien parece jugar un importante rol en algunas enfermedades. Resultados de laboratorio fueron confirmados por observaciones hechas en el campo sobre poliomielitis, viruela, fiebre aftosa, peste bovina y enfermedad de Newcastle; Es probable que la enfermedad de Marek. la bronquitis infecciosa aviar y otras numerosas enfermedades seandiseminadas de la misma manera. La diseminación a grandes distancias por corrientes de aire puede ser influenciada, hasta cierto punto, por la virulencia del agente causal y por la tasa de acentamiento para particulas de un tama?o, las cuales son óptimas para su acentamiento en el lugar de predilección del organismo específico. Mas aun, factores locales geográficos y climáticos pueden modificar grandemente los patrones de distribución de enfermedades diseminadas por el aire durante grandes epidemias ó epizootias: Se citan como ejemplos brotes específicos.

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Résumé Il a été démontré qu'un nombre croissant de maladies humaine et animale sont dísséminées par des microorganismes en suspension dans l'atmosphère. La viabilité de tels agents pathogènes décroit progressivement en fonction de l'influence des facteurs physiques et autres qui sont énumérés dans ce texte. L'humidité relative influence fortement cette possibilité de survie comme l'ont montré des études expérimentales, mais des différences de souches semblent aussi jouer un r?le important pour certaines maladies. Les résultats expérimentaux ont été confirmés par des observations faites sur le terrain à propos de la poliomyélite, la variole, la fièvre aphteuse, la peste bovine et la maladie de Newcastle; il est probable que la maladie de Marek, la bronchite infectieuse aviaire et de nombreuses autres infections se répandent de la même manière. La dissémination à longue distance par les courants aériens peut être influencée, dans une certaine mesure, par la virulence de l'agent causal et par le pourcentage de particules dont la taille est optimale pour leur arrivée au site d'élection du microorganisme spécifique. En outre, des facteurs géographique et climatique locaux peuvent grandement modifier le schéma épidémiologique des maladies disséminées par voie aérienne; des foyers spécifiques sont cités en example.

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Based on a paper presented at a Meeting of the Central Canada Veterinary Association on 9th December 1970.     

猪败血型链球菌病的诊疗报告

本文阐述了猪链球菌病的临床症状、实验室检验及防治方法，力求为科学防控猪链球菌病提供有益的探索和参考。     

Is the Production of Embryos in Small‐Scale Farming an Economically Feasible Enterprise?

The present assay attempts to evaluate the feasibility of using embryo transfer in small community farmers by in vivo study and by modelling the results obtained. From the total of 59 donor cows, 62.7% responded to treatment, with a significant difference (p = 0.002) in the percentage of the response between breeds, being 90.5% (19/21) in Holstein and 47.4% (18/38) in Brahman. A total of 283 embryos were graded as transferable, while 141 as non‐transferable, without difference in the percentage of transferable embryo by breed (p = 0.18). The mean of transferable embryos graded as class I and II was not different between Holstein and Brahman (p = 0.96 and p = 0.92, respectively); besides, no differences were observed in the other grades (non‐transferable). The highest difference in costs, regardless of its quality by breed, was seen in the lower levels of probable fertility of the embryo transferred, even reaching several hundred dollars. When modelling the expected costs for embryo produced and transferred, values can reach nearly $2000.00 when the probable fertility is only 10%. However, when the probable fertility was 60%, embryo cost was close to $300.00. This technology seems to be viable on average or high‐scale systems, having a superovulatory response between 60 and 80% with 4–6 transferrable embryos. Yet, in small‐scale farming, due to the reduced number of donors and/or recipients, the costs surpass the economical feasibility of the technique.     

Percentage of Ubiquitinated Spermatozoa does not Correlate with Fertilizing Capacity of Thawed Bovine Semen

In the spermatozoa of some species, the ubiquitin–proteasome system detects altered proteins and tags them for elimination by the proteasome. In some species' ejaculates, a high proportion of ubiquitinated spermatozoa (i.e. those having ubiquitin bound to the altered or damaged membrane proteins) has been related to infertility. The aim of this study was to assess whether the percentage of ubiquitinated spermatozoa relates to fertility of dairy bulls and whether ubiquitination increases during protein remodelling that occurs during in vitro spermatic capacitation. Thirty‐two frozen semen straws from four high‐fertility (ReproMax^®) and four normal‐fertility (Normal) Holstein‐Friesian sires were evaluated. Ubiquitinated and capacitated spermatozoa were quantified by sperm ubiquitin tag immunoassay and chlortetracycline stain, respectively. Fertilizing capacity of sires was assessed by in vitro fertilization. No differences were found between Normal and ReproMax^® sires with regard to the observed percentage of ubiquitinated spermatozoa (42.97 ± 3.69% and 49.68 ± 9.27%, respectively; p > 0.05). Additionally, no differences were found in the percentage of ubiquitinated spermatozoa as a consequence of spermatic capacitation in either Normal (42.97 ± 3.69% before capacitation vs 44.67 ± 7.5% after; p > 0.05) or ReproMax^® sires (49.68 ± 9.27% before vs 45.05 ± 7.51% after; p > 0.05). The percentage of ubiquitinated spermatozoa in a thawed sperm samples did not correlate with its in vitro fertilizing capacity; thus, this assay does not prove useful to detect in vivo fertility differences between sires. Additionally, protein degradation occurring during remodelling of the spermatozoon plasma membrane during the capacitation process does not seem to involve the ubiquitin–proteasome system.     

Microbial origin of the abdominal swelling affecting farmed larvae of gilt-head seabream, Sparus aurata L.

The aetiological agents of the abdominal swelling affecting farmed larvae of gilt-head seabream, Sparus aurata L., were studied. Four Vibrio strains were isolated from larvae of S. aurata affected by this disease, and all strains reproduced the disease in healthy larvae under controlled infection experiments, producing a significant increase of the mortality rates compared to the control (non-inoculated larvae). Several enzymatic properties, which can act as .virulence factors, were demonstrated both in the extracellular products (ECPs) and In live cells of the strains tested. Histopathological examinations of the infected fish larvae revealed important changes of the anterior intestine and liver characterized by a marked hyperthrophy of the intestinal epithelium and hepatocytes, and by a separation of the mucosal and submucosal layers in the digestive tube. These histological alterations were associated with the constant presence of cocobacillar bacteria in the anterior intestine and in the liver. However, the precise pathogenic mechanisms of the strains tested have not been completely elucidated yet.     

Longitudinal variation in fish species composition in the Angabanga river, Papua New Guinea with observations on the trophic status of certain fish species

Abstract– Longitudinal variation in fish species composition at various sites on the Angabanga river showed an increase in diversity from source to mouth and that only a few fish species occur at all sites. The fish assemblage of floodplain pool areas contained fewer species than the main channel and was dominated by two exotic species Oreochrornis mossambicus (Peters 1852) and Trichoguster pectoralis (Regan 1910). Most native fish species utilize invertebrates as a food source. The absence of indigenous detritus/substrate feeders in the Angabanga community may account in part for the success of the two introduced species on the floodplain.