Case Report: Outbreak of Bumper Car Disease Caused by Anophryoides haemophila in a Lobster Holding Facility in Nova Scotia,Canada

Abstract

This case report provides pathologic and confirmatory molecular characterization of an outbreak of bumper car disease caused by the scuticociliate Anophryoides haemophila in American lobster Homarus americanus, from a commercial holding facility in Nova Scotia, Canada. Although sporadically and anecdotally reported to be present in Atlantic Canada, this is the first report detailing observations from a natural outbreak of bumper car disease by gross and microscopic pathology and its positive identification by small subunit rRNA gene sequencing. Randomly amplified polymorphic DNA analysis confirmed that the genotype of the present outbreak isolate is identical to the original isolate of A. haemophila reported from Maine lobsters in 1993.     

Effects of formalin, chloramine-T, and low salinity dip on the behavior and hemolymph biochemistry of the American lobster.

The purpose of this research was to investigate the salinity and formalin sensitivity of a ciliate parasite (Anophryoides haemophila) of the American lobster (Homarus americanus), and to examine the target-animal (lobster) safety of chemical-bath treatments involving low salinity, formalin, or chloramine-T that could be used to control this parasite in lobster pounds. "Bumper car" disease, caused by An. haemophila, is an important concern to lobster pound operators in eastern North America, because of the implicated lobster mortality rate and the general lack of preventive and therapeutic intervention regimes. We determined, using an in vitro method, that formalin at 50 mg/L, or low salinity at 8.0 parts per thousand (ppt) for 1 hour killed 100% of the parasites. When healthy lobsters were exposed to formalin at 200 mg/L, there were no negative behavioral responses and no significant differences in a panel of hemolymph biochemical indices. Similar results occurred when lobsters were exposed to chloramine-T, a common finfish therapeutic agent for topical bacteria and protozoa, at 10 mg/L for 1 hour. The low salinity treatment (8.0 ppt) resulted in significant adverse changes in lobster behavior and biochemical indices; however, these changes did not persist for more than 1 week after treatment ended. Although these treatments are unlikely to kill parasites that have already invaded the lobster carapace, they should be effective in reducing parasite loads on the gill and carapace surface of the lobster and in the environment of the impoundment housing.     

Safety of florfenicol in the adult lobster (Homarus americanus)

Aerococcus viridans, the causative agent of the disease gaffkemia, was a major cause of mortality in lobsters (Homarus americanus) held in tidal impoundments during the 1970s and 1980s. Despite reports of an increase in the mortality of lobsters during impoundment, and the widespread prophylactic use of oxytetracycline against A. viridans, this bacterium has not been detected in active disease surveillance of the Maine postcapture lobster population. However, Photobacterium indicum may be an emerging opportunistic pathogen of stressed lobsters. An acute toxicity trial was conducted as a rapid screening procedure for the potential future use of the antibiotic florfenicol. Based on the results of this experiment, florfenicol appears to be well tolerated in adult H. americanus by intrapericardial injection at the 10-100 mg/kg dose. Oxytetracycline dihydrate is contraindicated by intrapericardial injection at the 10-100 mg/kg dose.     

Occurrence of gaffkaemia in Lobsters in Norway.

Gaffkaemia is a bacterial disease which causes periodic, lethal epizootics in holding facilities for live American (Homarus americanus) and European (Homarus vulgaris) lobsters (Snieszko & Taylor 1947, Roskam 1957). Gaffkaemia, with the causative agent Aerococcus viridans, has been diagnosed in many countries in Europe and elsewhere. Roskam (1957, 1958) reported the disease in lobsters imported to the Netherlands from Norway. In Norway, however, the disease has never before been reported, though an experiment has shown that gaffkaemia could be induced in lobsters from a Norwegian area with injections of the A.T.C.C. type strain no. 10400 of the causative agent (Møllerud 1971).     

蛋壳胶护膜研究进展

蛋产品安全一直是人们重点关注的问题,也是研究的热点。随着福利养殖的推广,鸡蛋被微生物污染的机率增大。除了加强饲养管理之外,强化鸡蛋自身保护屏障从而抵抗细菌入侵也十分重要。胶护膜是蛋壳最外层覆盖的无色透明膜,鸡蛋产出前1.5~2.0 h于子宫部形成,是蛋抵御微生物污染的重要屏障,研究表明胶护膜较厚的蛋不易被细菌入侵。鸡蛋蛋壳胶护膜主要由糖蛋白（90%）、多糖（4%）、脂质（3%）和以羟基磷灰石晶体形式存在的无机磷（3%）组成。胶护膜中含有溶菌酶C、卵转铁蛋白、ovocleidin-32等多种抗菌蛋白,可有效地阻碍细菌跨壳污染。此外,胶护膜能终止蛋壳矿化、帮助蛋产出前在子宫中翻转、调节水气交换以延长鸡蛋的保存时间。本文对胶护膜的结构、生物学功能、胶护膜品质评价方法及胶护膜质量的影响因素等方面进行了阐述,并对尚待解决的问题展开了探讨。     

延长龙虾软壳期的方法

软壳龙虾的可食部分比硬壳龙虾高出许多.食用软壳龙虾可以有效地利用龙虾中的营养物质,并且能够减少垃圾的排放.延长龙虾软壳期的方法主要有快速蜕壳法和延缓新壳硬化法.饲料中添加蜕皮激素类物质,有助于加速龙虾蜕壳.降温可以降低软壳龙虾的新陈代谢速度,以达到让软壳龙虾长时间不变硬的目的.     

Relationship between shell structure and movement of Salmonella enteritidis across the eggshell wall.

1. Ultrastructural analyses of the eggshells of one strain of commercial layers indicated that the cuticular layer is rarely present as an even covering over the shell surface and the paired shell membranes are invariably pitted with holes larger than bacterial dimensions. 2. The above conditions pertain irrespective of the age of the laying bird. 3. Bacterial penetration of the eggshell is independent of pore numbers. 4. In the absence of a functional cuticle and with the shell membranes removed, bacteria are checked in their movement by structural modifications in the mammillary layer.     

Progesterone and testosterone elicit increases in the duration of shell formation in domestic hens

Injection of progesterone or testosterone in hens 4 and 10 h after ovulation increased the intervals between ovipositions and shell weights. The effects were dose-dependent. Expulsion of the egg from treated hens at the expected time of oviposition suppressed the increase in shell weight and deposition of the cuticle. The duration of shell formation had therefore been increased by the injections of progesterone or testosterone. Injections of progesterone 16 h or of testosterone 15 h after ovulation advanced oviposition and reduced shell weight. Testosterone propionate was more efficient than testosterone in its action on the duration of shell formation. Oestradiol was ineffective. Indomethacin delayed oviposition but did not change the duration of shell formation. These results suggest that the duration of shell formation is under the control of hormonal factors and that the larger follicles of the ovary, may be involved in its control.     

Identification of Aerococcus Viridans by Means of Co-Agglutination

Gaffkemia, which has recently been reviewed by Stewart & Rabin (1970) and by Stewart (1975), is a fatal bacterial disease of the American and European lobster (Homarus americanus and Homarus vulgaris) (Snieszko & Taylor 1947). The causal agent, first classified as Gaffkya homari (Hitchner & Snieszko 1947), is now classified as Aerococcus viridans (Williams et aL 1953, Buchanan & Gibbons 1974).     

Eggshell characteristics and penetration by Salmonella enterica serovar Enteritidis through the production period of a layer flock

1. Egg weight, shell thickness, number of pores, cuticle deposition and ability of Salmonella enterica serovar Enteritidis (SE) to penetrate the shell were determined for eggs from one layer flock through the entire production period. 2. Penetration was assessed by filling the eggs with a selective medium that allowed visualising Salmonella growth on the inside of the shell and membrane complex. After inoculation of each shell with on average 2.59 log cfu, the eggs were stored for up to 20 d at 20 degrees C and 60% relative humidity (RH). 3. On average 38.7% of the eggshells became penetrated. Mostly penetration occurred on d 3. Although it affected all shell characteristics studied, hen age did not significantly influence eggshell penetration. 4. No correlations were observed between any of the shell characteristics studied and the ability of SE to penetrate the shell. The growth of SE on the shell is of major importance because shell contamination at 20 d of storage and SE penetration were highly correlated.     

Morphological and histochemical observations of the organic components of ostrich eggshell

The organic component of the avian eggshell can be divided into 3 portions, the shell membranes, the matrix and the cuticle. These have been well characterised in the chicken but little has been published with regard to the ostrich (Struthio camelus). A number of recent studies have indicated that the cause of intra-shell embryonic deaths in the ostrich is similar to intra-shell embryonic deaths that occur in the chicken. These deaths in the chicken are associated with the loss of or damage to the waxy cuticle and other organic components of the eggshell, which is reported to be absent in the ostrich eggshell. In this study, preliminary morphological and histochemical analyses, at the level of the light and electron microscope, have characterised the various organic components of the ostrich eggshell. The results of the histochemical and electron microscopical analyses suggest that there may only be 1 shell membrane in this species, which could play a major role in the limitation of bacterial penetration to the embryonic chamber The shell membrane has a distinct elemental profile as determined by EDS analysis. The matrix is shown to decrease in mesh size from the mammillary layer to the vertical crystal layer. The closer packing of the mesh may indicate the presence of a morphologically discernible termination signal to calcification or the remnants of an evolutionary calcified cuticle. The matrix of the pores may also form a defensive barrier against bacterial invasion, which could be damaged as a result of dipping the eggs before incubation.     

The cuticle: A barrier to liquid and particle penetration of the shell of the hen's egg

The cuticle of the egg shell prevents water‐soluble dyes and carbon black from entering the majority of pores. A small percentage of eggs obtained from a commercial flock had no cuticle and their shells were easily invaded by carbon black. Chemical or physical removal of cuticle resulted in the pores being flooded with water which carried in carbon black. Such eggs did not, however, absorb water at a rate equal to that of eggs from which a piece of shell had been removed. This indicated that the pores without a cap and plug of cuticular material resisted the movement of water. The role of the cuticle and shell in repelling water is discussed and a function akin to that of the plastron of insect eggs proposed.     

Cuticle,shell porosity and water uptake through hens’ eggshells

1. There was no correlation between water uptake by a warm egg (37 °C) immersed in iced water and the shell's porosity as measured by water vapour conductance.

2. Eggs lacking cuticle on the shell took up more water than those having cuticle. There was no correlation between water uptake and the water vapour conductance of cuticle‐less eggshells.

3. In general there was no correlation between the amount of water taken up by an egg and the weight of cuticle on its shell. With some eggs there was an association between water uptake and the extent of fissuring of the cuticle.

4. It is postulated that the pore canals impede water flow such that osmotic forces acting across the shell membranes do not influence water uptake by eggs.

     

Host specific differences alter the requirement for certain Salmonella genes during swine colonization

The pathogenic potential of Salmonella is determined during the complex interaction between pathogen and host, requiring optimal regulation of multiple bacterial genetic systems within variable in vivo environments. The mouse model of systemic disease has been an extremely productive model to investigate the pathogenesis of Salmonella enterica serovar Typhimurium (S. Typhimurium). Although the mouse model is a widely used paradigm for studying the pathogenesis of systemic disease caused by Salmonella, investigations concerning food safety interventions should employ natural hosts to examine gastrointestinal colonization by Salmonella. Recent research has demonstrated specific differences in the attenuation of certain S. Typhimurium mutants in mice compared to swine. This variation in pathogenesis between the mouse model and pigs for the S. Typhimurium mutants is presumably dependent upon either the requirements for specific gene products during systemic disease (mouse) versus gastrointestinal colonization (pig) or host specific differences. In addition, host specific diversity in Salmonella colonization of swine has also been described in comparison to other food-producing animals, including cattle and chickens. Differences in Salmonella colonization and pathogenesis across diverse animal species highlight the importance of species-specific studies of gastrointestinal colonization for the development of Salmonella interventions to enhance pork safety.     

Understanding regulations affecting pet foods

In the United States, pet foods are subject to regulation at both the federal and the state levels. The US Food and Drug Administration has jurisdiction over all animal feeds (including pet foods, treats, chews, supplements, and ingredients) in interstate commerce, which includes imported products. Many states adopt and enforce at least in part the Association of American Feed Control Officials Model Bill and Model Regulations for Pet Food and Specialty Pet Food. Thus, all pet foods in multi-state distribution are subject to a host of labeling requirements covering aspects such as product names, ingredient lists, nutrient content guarantees, and nutritional adequacy statements. Ingredients must be GRAS (generally recognized as safe) substances, approved food additives, or defined by Association of American Feed Control Officials for their intended use. Pet food labels may not bear claims that are false or misleading or that state or imply use for the treatment or prevention of disease. Pet foods that are found to be adulterated or misbranded may be subject to seizure or other enforcement actions.     

Pathology and tissue tropism of natural West Nile virus infection in birds: a review

West Nile virus (WNV) is a globally distributed arthropod-borne flavivirus capable of infecting a wide variety of vertebrates, with birds as its natural reservoir. Although it had been considered a pathogen of little importance for birds, from the 1990’s, and especially after its introduction in the North American continent in 1999, thousands of birds have succumbed to West Nile infection. This review summarizes the pathogenesis and pathology of WNV infection in birds highlighting differences in lesion and antigen distribution and severity among bird orders and families. Despite significant species differences in susceptibility to infection, WNV associated lesions and viral antigen are present in the majority of organs of infected birds. The non-progressive, acute or more prolonged course of the disease accounts for part of the differences in lesion and viral antigen distribution and lesion severity. Most likely a combination of host variables and environmental factors in addition to the intrinsic virulence and pathogenicity of the infecting WNV strain influence the pathogenesis of the infection.     

Effect of production system and flock age on egg quality and total bacterial load in commercial laying hens

The shell of the egg is essential in providing shape to the egg and ensuring safe packaging of the internal contents; however, shell defects have been shown to increase the risk of microbial contamination of eggs. Eggs were collected from commercial cage and free-range flocks at the ages of 25, 35, 45, 55, 65, and 75 wk. From each collection per flock, 30 eggs were processed for the eggshell and egg internal quality determination, 30 eggs for cuticle estimation, 30 eggs for mammillary layer ultrastructural features scoring, and 60 eggs for egg microbial enumeration. Translucency score and shell reflectivity were significantly higher in free-range eggs and increased with flock age in both production systems. Egg weight, shell weight, percentage shell, shell thickness, albumen height, Haugh unit, and yolk color were higher for cage eggs. The amount of cuticle was higher in cage eggs and fluctuated with flock age in both production systems. For the mammillary layer ultrastructural variables, a significant effect of production system and flock age was observed for early fusion, Type A bodies, and Type B bodies, whereas aragonite, depression, erosion, and hole were rarely observed. Variability of mammillary cap size, the incidence of poor mammillary cap quality, incidence of late fusion, alignment, Type A bodies, Type B bodies, and cubic cone formation were greater in the free-range versus cage system and increased with flock age in both production systems. The incidence of confluence and early fusion were greater in cage eggs and decreased with age in both production systems. Significantly lower total microbial load was observed for cage compared with free-range eggs, but the overall bacterial load recorded in this study was low. It can be concluded that cage eggs were better in overall quality when directly compared with free-range eggs.     

Relevance in pathogenesis research

Research on pathogenesis of bacterial diseases involves exploration of the intricate and complex interactions among pathogen, host, and environment. Host-parasite-environment interactions that were relatively simple were the first to be understood. They include intoxications in which ingestion of a powerful bacterial toxin was sufficient to cause disease. In more complex cases bacteria occupy a variety of niches in the host and attack at an opportune time. Some bacterial pathogens have a brief encounter with the host; others are long-term guests. This variety of relationships involves a wide range of strategies for survival and transmission of bacterial pathogens. Molecular genetics, genomics and proteomics have facilitated understanding of the pathogens and hosts. Massive information often results from such studies and determining the relevance of the data is frequently a challenge. In vitro studies often attempt to simulate one or two critical aspects of the environment, such as temperature, pH, and iron concentration, that may provide clues as to what goes on in the host. These studies sometimes identify critical bacterial virulence factors but regulation of bacterial virulence and host response is complex and often not well understood. Pathogenesis is a process of continuous change in which timing and degree of gene expression are critical and are highly regulated by the environment. It is impossible to get the full picture without the use of natural or experimental infections, although experimental infections involve ethical and economic considerations which may act as a deterrent.     

Pathogenesis of caseous lymphadenitis in sheep and goats

The progress of caseous lymphadenitis in sheep and goats is described as involving primary wound infection, lymphatic and haematogenous dissemination, and secondary infection of lymph nodes and various visceral organs. This is followed by elimination or containment of infection, the latter being represented by the characteristic caseous lesions. Resistance to infection is complex involving components of both the specific and non-specific host response. The role of these in pathogenesis is discussed. Bacterial factors including the phospholipase exotoxin and cytotoxic lipid contribute to pathogenesis at a local level with little likelihood of systemic effect in the natural disease. In a disease such as caseous lymphadenitis, lesion site, size or number do not indicate severity of disease but rather, reflect the ability of the host to mount a cellular response to infection.     

The influence of the cuticle on egg‐shell strength

1. Sixty sound eggs, assumed to have shell cuticle, were paired according to egg‐shell deformation value.

2. Egg weight and shell quality characteristics were recorded for the eggs and the cuticle was then removed from one egg of each pair.

3. Egg weight and shell quality were re‐assessed for the eggs from which the cuticle had been removed.

4. The cuticle made a significant (P<0.01) contribution to shell thickness and removal of it appeared to reduce shell strength when measured directly, but the method of measurement was too variable to establish this with statistical significance.