Fish Eating Birds Can Spread Bacterial Diseases Between Catfish Ponds

Severe outbreaks of Motile Aeromonad Septicemia disease in commercial catfish aquaculture ponds have been associated with a virulent Aeromonas hydrophila strain (VAh) that is genetically distinct from less virulent strains. We demonstrated that Great Egrets (Arde alba), Double-crested Cormorants (Phalacrocorax auritus), American White Pelicans (Pelecanus erythrorhynchos), and Wood Storks (Mycteria americana) can carry and shed viable VAh after consuming fish infected with Vah. Edwardsiella ictaluri and E. tarda are considered the primary species of Edwardsiella to cause disease outbreaks in North American catfish aquaculture. Genetic analysis has determined that most isolates designated as E. tarda were actually a new species, E. piscicida. There has been an increase in E. piscicida diagnostic cases in recent years possibly due to an increase in hybrid (Channel x blue) catfish production. We conducted a study to determine if Great Egrets (Ardea alba) shed viable E. piscicida when fed catfish infected with the bacteria. Great Egrets fed infected fish shed viable E. piscicida bacteria for multiple days, (Table 1), after last consuming infected fish on day 2 of the study. Great Egrets in the control group did not shed the bacteria. Given that Great Egrets can shed viable E. piscicida after consuming diseased fish, we hypothesize that they could also serve as a reservoir for E. piscicida and could spread the pathogen while predating fish in catfish ponds. Additional research is needed to determine if this shedding could cause disease in these ponds

Potential of Double-crested Cormorants (\u3ci\u3ePhalacrocorax auritus\u3c/i\u3e), American White Pelicans (\u3ci\u3ePelecanus erythrorhynchos\u3c/i\u3e), and Wood Storks (\u3ci\u3eMycteria americana\u3c/i\u3e) to Transmit a Hypervirulent Strain of \u3ci\u3eAeromonas hydrophila\u3c/i\u3e between Channel Catfish Culture Ponds

Aeromonas hydrophila is a Gramnegative bacterium ubiquitous to freshwater and brackish aquatic environments that can cause disease in fish, humans, reptiles, and birds. Recent severe outbreaks of disease in commercial channel catfish (Ictalurus punctatus) aquaculture ponds have been associated with a hypervirulent Aeromonas hydrophila strain (VAH) that is genetically distinct from less virulent strains. The epidemiology of this disease has not been determined. Given that research has shown that Great Egrets (Ardea alba) can shed viable hypervirulent A. hydrophila after consuming diseased fish, we hypothesized that Doublecrested Cormorants (Phalacrocorax auritus), American White Pelicans (Pelecanus erythrorhynchos), and Wood Storks (Mycteria americana) could also serve as a reservoir for VAH and spread the pathogen during predation of fish in uninfected catfish ponds. All three species, when fed VAH-infected catfish, shed viable VAH in their feces, demonstrating their potential to spread VAH

A broadly applicable method to characterize large DNA viruses and adenoviruses based on the DNA polymerase gene

BACKGROUND: Many viral pathogens are poorly characterized, are difficult to culture or reagents are lacking for confirmatory diagnoses. We have developed and tested a robust assay for detecting and characterizing large DNA viruses and adenoviruses. The assay is based on the use of degenerate PCR to target a gene common to these viruses, the DNA polymerase, and sequencing the products. RESULTS: We evaluated our method by applying it to fowl adenovirus isolates, catfish herpesvirus isolates, and largemouth bass ranavirus (iridovirus) from cell culture and lymphocystis disease virus (iridovirus) and avian poxvirus from tissue. All viruses with the exception of avian poxvirus produced the expected product. After optimization of extraction procedures, and after designing and applying an additional primer we were able to produce polymerase gene product from the avian poxvirus genome. The sequence data that we obtained demonstrated the simplicity and potential of the method for routine use in characterizing large DNA viruses. The adenovirus samples were demonstrated to represent 2 types of fowl adenovirus, fowl adenovirus 1 and an uncharacterized avian adenovirus most similar to fowl adenovirus 9. The herpesvirus isolate from blue catfish was shown to be similar to channel catfish virus (Ictalurid herpesvirus 1). The case isolate of largemouth bass ranavirus was shown to exactly match the type specimen and both were similar to tiger frog virus and frog virus 3. The lymphocystis disease virus isolate from largemouth bass was shown to be related but distinct from the two previously characterized lymphocystis disease virus isolates suggesting that it may represent a distinct lymphocystis disease virus species. CONCLUSION: The method developed is rapid and broadly applicable to cell culture isolates and infected tissues. Targeting a specific gene for in the large DNA viruses and adenoviruses provide a common reference for grouping the newly identified viruses according to relatedness to sequences of reference viruses and the submission of the sequence data to GenBank will build the database to make the BLAST analysis a valuable resource readily accessible by most diagnostic laboratories. We demonstrated the utility of this assay on viruses that infect fish and birds. These hosts are phylogenetically distant from mammals yet, sequence data suggests that the assay would work equally as well on mammalian counterparts of these groups of viruses. Furthermore, we demonstrated that obtaining genetic information on routine diagnostic samples has great potential for revealing new virus strains and suggesting the presence of new species

Recycled water causes no salinity or toxicity issues in Napa vineyards

In response to Napa Sanitation District's interest in expanding its delivery of recycled water to vineyards for irrigation, we conducted a feasibility study to assess the suitability of the water for this use. We adopted two approaches: comparing the water quality characteristics of the recycled water with those of other local sources of irrigation water, and evaluating soil samples from a vineyard that was irrigated for 8 years with the recycled water. Results indicate that the quality of the recycled water is suitable for irrigation, and also that long-term accumulation of salts and toxic ions have not occurred in the vineyards studied and are unlikely to occur. Nutrients in the recycled water may be beneficial to vineyards, though the levels of nitrogen may need to be reduced by planting cover crops in some vineyards

Antigenic Characterization of H3 Subtypes of Avian Influenza A Viruses from North America

Besides humans, H3 subtypes of influenza A viruses (IAVs) can infect various animal hosts, including avian, swine, equine, canine, and sea mammal species. These H3 viruses are both antigenically and genetically diverse. Here, we characterized the antigenic diversity of contemporary H3 avian IAVs recovered from migratory birds in North America. Hemagglutination inhibition (HI) assays were performed on 37 H3 isolates of avian IAVs recovered from 2007 to 2011 using generated reference chicken sera. These isolates were recovered from samples taken in the Atlantic, Mississippi, Central, and Pacific waterfowl migration flyways. Antisera to all the tested H3 isolates cross-reacted with each other and, to a lesser extent, with those to H3 canine and H3 equine IAVs. Antigenic cartography showed that the largest antigenic distance among the 37 avian IAVs is about four units, and each unit corresponds to a 2 log 2 difference in the HI titer. However, none of the tested H3 IAVs cross-reacted with ferret sera derived from contemporary swine and human IAVs. Our results showed that the H3 avian IAVs we tested lacked significant antigenic diversity, and these viruses were antigenically different from those circulating in swine and human populations. This suggests that H3 avian IAVs in North American waterfowl are antigenically relatively stable. Además de infectar a los seres humanos, los subtipos H3 del virus de la influenza A (IAVs) pueden infectar a varios huéspedes animales, incluyendo aves, porcinos, equinos, caninos, y especies de mamíferos marinos. Estos virus H3 son tanto antigénica y genéticamente diversos. En este estudio, se caracterizó la diversidad antigénica de virus H3 contemporáneos recuperados de aves migratorias en América del Norte. Se realizaron pruebas de inhibición de la hemaglutinación (HI) en 37 H3 aislamientos de origen aviar recuperados de 2007 a 2011 usando sueros de pollo de referencia. Estos aislamientos fueron recuperados de las muestras tomadas de las rutas migratorias de aves acuáticas del Atlántico, Mississippi, Centro y del Pacífico. Los antisueros de todos los aislamientos H3 analizados mostraron reacciones cruzadas entre sí y en menor medida, con aquellos virus H3 de origen canino y equino. La cartografía antigénica demostró que la mayor distancia antigénica entre los 37 virus de este tipo de aves es de aproximadamente cuatro unidades, y cada unidad corresponde a una diferencia de dos logaritmos en el título de inhibición de la hemaglutinación. Sin embargo, ninguno de los virus H3 de este tipo mostró reacción cruzada con sueros de hurón específicos para virus de cerdos y humanos contemporáneos. Estos resultados mostraron que los virus H3 de origen aviar que se analizaron carecían de diversidad antigénica significativa y estos virus fueron antigénicamente diferentes de las que circulan en poblaciones de cerdos y de humanos. Esto sugiere que los virus H3 de aves acuáticas de América del Norte son relativamente estables antigénicamente

The association of circulating amylin with β-amyloid in familial Alzheimer's disease.

Introduction: This study assessed the hypothesis that circulating human amylin (amyloid-forming) cross-seeds with amyloid beta (Aβ) in early Alzheimer's disease (AD). Methods: Evidence of amylin-AD pathology interaction was tested in brains of 31 familial AD mutation carriers and 20 cognitively unaffected individuals, in cerebrospinal fluid (CSF) (98 diseased and 117 control samples) and in genetic databases. For functional testing, we genetically manipulated amylin secretion in APP/PS1 and non-APP/PS1 rats. Results: Amylin-Aβ cross-seeding was identified in AD brains. High CSF amylin levels were associated with decreased CSF Aβ42 concentrations. AD risk and amylin gene are not correlated. Suppressed amylin secretion protected APP/PS1 rats against AD-associated effects. In contrast, hypersecretion or intravenous injection of human amylin in APP/PS1 rats exacerbated AD-like pathology through disruption of CSF-brain Aβ exchange and amylin-Aβ cross-seeding. Discussion: These findings strengthened the hypothesis of circulating amylin-AD interaction and suggest that modulation of blood amylin levels may alter Aβ-related pathology/symptoms

Population Dynamics and Angler Exploitation of the Unique Muskellunge Population in Shoepack Lake, Voyageurs National Park, Minnesota

A unique population of muskellunge Esox masquinongy inhabits Shoepack Lake in Voyageurs National Park, Minnesota. Little is known about its status, dynamics, and angler exploitation, and there is concern for the long-term viability of this population. We used intensive sampling and mark–recapture methods to quantify abundance, survival, growth, condition, age at maturity and fecundity and angler surveys to quantify angler pressure, catch rates, and exploitation. During our study, heavy rain washed out a dam constructed by beavers Castor canadensis which regulates the water level at the lake outlet, resulting in a nearly 50% reduction in surface area. We estimated a population size of 1,120 adult fish at the beginning of the study. No immediate reduction in population size was detected in response to the loss of lake area, although there was a gradual, but significant, decline in population size over the 2-year study. Adults grew less than 50 mm per year, and relative weight (W r) averaged roughly 80. Anglers were successful in catching, on average, two fish during a full day of angling, but harvest was negligible. Shoepack Lake muskellunge exhibit much slower growth rates and lower condition, but much higher densities and angler catch per unit effort (CPUE), than other muskellunge populations. The unique nature, limited distribution, and location of this population in a national park require special consideration for management. The results of this study provide the basis for assessing the long-term viability of the Shoepack Lake muskellunge population through simulations of long-term population dynamics and genetically effective population size

Managing Wicked Herbicide-Resistance: Lessons from the Field

Herbicide resistance is ‘wicked’ in nature; therefore, results of the many educational efforts to encourage diversification of weed control practices in the United States have been mixed. It is clear that we do not sufficiently understand the totality of the grassroots obstacles, concerns, challenges, and specific solutions needed for varied crop production systems. Weed management issues and solutions vary with such variables as management styles, regions, cropping systems, and available or affordable technologies. Therefore, to help the weed science community better understand the needs and ideas of those directly dealing with herbicide resistance, seven half-day regional listening sessions were held across the United States between December 2016 and April 2017 with groups of diverse stakeholders on the issues and potential solutions for herbicide resistance management. The major goals of the sessions were to gain an understanding of stakeholders and their goals and concerns related to herbicide resistance management, to become familiar with regional differences, and to identify decision maker needs to address herbicide resistance. The messages shared by listening-session participants could be summarized by six themes: we need new herbicides; there is no need for more regulation; there is a need for more education, especially for others who were not present; diversity is hard; the agricultural economy makes it difficult to make changes; and we are aware of herbicide resistance but are managing it. The authors concluded that more work is needed to bring a community-wide, interdisciplinary approach to understanding the complexity of managing weeds within the context of the whole farm operation and for communicating the need to address herbicide resistance

Managing Wicked Herbicide-Resistance: Lessons from the Field

Herbicide resistance is ‘wicked’ in nature; therefore, results of the many educational efforts to encourage diversification of weed control practices in the United States have been mixed. It is clear that we do not sufficiently understand the totality of the grassroots obstacles, concerns, challenges, and specific solutions needed for varied crop production systems. Weed management issues and solutions vary with such variables as management styles, regions, cropping systems, and available or affordable technologies. Therefore, to help the weed science community better understand the needs and ideas of those directly dealing with herbicide resistance, seven half-day regional listening sessions were held across the United States between December 2016 and April 2017 with groups of diverse stakeholders on the issues and potential solutions for herbicide resistance management. The major goals of the sessions were to gain an understanding of stakeholders and their goals and concerns related to herbicide resistance management, to become familiar with regional differences, and to identify decision maker needs to address herbicide resistance. The messages shared by listening-session participants could be summarized by six themes: we need new herbicides; there is no need for more regulation; there is a need for more education, especially for others who were not present; diversity is hard; the agricultural economy makes it difficult to make changes; and we are aware of herbicide resistance but are managing it. The authors concluded that more work is needed to bring a community-wide, interdisciplinary approach to understanding the complexity of managing weeds within the context of the whole farm operation and for communicating the need to address herbicide resistance

Managing Herbicide Resistance: Listening to the Perspectives of Practitioners. Procedures for Conducting Listening Sessions and an Evaluation of the Process

Seven half-day regional listening sessions were held between December 2016 and April 2017 with groups of diverse stakeholders on the issues and potential solutions for herbicide-resistance management. The objective of the listening sessions was to connect with stakeholders and hear their challenges and recommendations for addressing herbicide resistance. The coordinating team hired Strategic Conservation Solutions, LLC, to facilitate all the sessions. They and the coordinating team used in-person meetings, teleconferences, and email to communicate and coordinate the activities leading up to each regional listening session. The agenda was the same across all sessions and included small-group discussions followed by reporting to the full group for discussion. The planning process was the same across all the sessions, although the selection of venue, time of day, and stakeholder participants differed to accommodate the differences among regions. The listening-session format required a great deal of work and flexibility on the part of the coordinating team and regional coordinators. Overall, the participant evaluations from the sessions were positive, with participants expressing appreciation that they were asked for their thoughts on the subject of herbicide resistance. This paper details the methods and processes used to conduct these regional listening sessions and provides an assessment of the strengths and limitations of those processes