Fish pathogen screening and its influence on the likelihood of accidental pathogen introduction during fish translocations

Fish translocations are an important tool in fisheries management, yet translocating fish carries the risk of introducing unwanted pathogens. Although pathogen screening can be a useful tool for managing the risk associated with fish translocations, screening cannot eliminate this risk. This paper addresses these problems by demonstrating that two elements must be considered when designing efficient and effective aquatic pathogen screening programs: (1) how many fish to screen and (2) how long to continue screening programs when repeated testing detects zero infected individuals. The chance that infected fish are translocated despite screening is the joint probability of (1) the failure of the screening to detect infected fish in the sample and (2) the actual presence of infected fish in the translocation batch. Our analysis demonstrates that transfer of an infected fish is most likely to occur at moderately low levels of pathogen prevalence because the probability of detecting at least one infected fish through screening increases as pathogen prevalence increases. Small screening samples (i.e., with a low number of individuals) are most likely to detect infected fish when pathogen prevalence is relatively high (i.e., > 5%). Screening programs should terminate after some number of successive screening events in which no infected individuals have been detected. The number of screening events is a function of the cost of the screening program, the cost of a pathogen translocation, and the probability that an infected fish will be transferred. Furthermore, our analysis indicates that the cost of a disease outbreak has relatively little effect on the length of time the screening program should continue. A more pronounced result is that screening programs that are inexpensive or allow a higher probability of pathogen translocation should be continued longer.     

Palatal sclerotherapy: a potentially useful treatment of intermittent dorsal displacement of the soft palate in juvenile standardbred racehorses

This study was aimed at evaluating the tolerability and the efficacy of palatal sclerotherapy in juvenile standardbred racehorses with easily audible "snoring-like" respiratory noises suspected to be the result of intermittent dorsal displacement of the soft palate. The palate of 8 horses was injected with sodium tetradecyl sulfate under videoendoscopic guidance. Palatal sclerotherapy resulted in resolution of the respiratory noise in 7 horses, improvement of performance in 6 horses, and mild side effects in only 3 horses. This preliminary study suggests that palatal sclerotherapy is a safe, repeatable, inexpensive, and promising technique that should be considered as an alternative to existing treatments of intermittent dorsal displacement of the soft palate.     

Detailed genetic analysis of feeding behaviour in Romane lambs and links with residual feed intake

Breeding strategies based on feed efficiency are now implemented in most animal species using residual feed intake (RFI) criteria. Although relevant, the correlated responses of feeding behaviour traits resulting from such selection on RFI are poorly documented. We report the estimated feeding behaviour at three time levels (visit, meal and day) and genetic parameters between the feeding behaviour traits and their links with RFI and its components. Feed intake, feeding duration at three time levels (per visit, meal and day), feeding rate, number of visits and time‐between‐visits were estimated for 951 Romane lambs fed via automatic concentrate feeders. Heritability estimates of feeding behaviour traits ranged from 0.19 to 0.54 with higher estimates for the day level than the visit level. Daily feed intake was not genetically linked to feed intake at the visit level, whereas feeding duration between visit and day levels was moderately correlated (R_g = +0.41 ± 0.12). RFI was not significantly correlated with feeding rate, but was positively linked to feed intake and feeding duration at the day level (+0.73 ± 0.09 and +0.41 ± 0.13, respectively) and negatively at the visit level (?0.33 ± 0.14 and ?0.22 ± 0.17, respectively). Selecting animals with lower RFI values might modify their feeding behaviour by increasing feed intake and feeding duration at the visit level but decrease the number of visits per day (+0.51 ± 0.14).     

Assessment of naturally acquired neutralizing antibodies against rabies Lyssavirus in a subset of Nunavik’s Inuit population considered most at risk of being exposed to rabid animals

Contact with infected saliva through the bite of a rabid animal is the main route of infection with the rabies Lyssavirus in humans. Although a few individuals have survived the infection, rabies remains the most lethal zoonotic infection worldwide. Over the last century, the dogma that rabies is invariably fatal has been challenged by the survival and recovery of infected animals. In humans, 11 studies have found rabies virus‐specific antibodies in unvaccinated individuals exposed to rabies virus reservoir species, suggesting the possibility of asymptomatic rabies virus infection, contact with non‐infectious virus or exposure to the virus without viral replication. Two of these studies were conducted in Arctic hunters. Considering the extensive exposure of Nunavik's Inuit to potentially infected animals through hunting, trapping, skinning and the preparation of Arctic carnivores, we analysed archived serum samples from the 2004 Nunavik Inuit Health Survey for the presence of rabies virus‐neutralizing antibodies (rVNA) in this sub‐population. A total of 196 participants who were considered at highest risk for exposure to rabies virus were targeted. Serum samples were tested for the presence of rVNA using a variation of the fluorescent antibody virus neutralization test, an assay recommended for the quantification of neutralizing antibody titres following vaccination. Our study identified two seropositive individuals among the 196 participants but a review of their medical record and a phone interview revealed previous vaccination. Our results do not provide evidence for naturally acquired rVNA in Nunavik's Inuit population.     

Age‐related morphometric changes of the tidemark in the ovine stifle

Though the ovine stifle is commonly used to study osteoarthritis, there is limited information about the age‐related morphometric changes of the tidemark. The objective of this study was to document the number of tidemarks in the stifle of research sheep without clinical signs of osteoarthritis and of various ages (n = 80). Articular cartilage of the medial and lateral tibial condyles and of the medial and lateral femoral condyles was assessed by histology: (a) to count the number of tidemark; and (b) to assess the OARSI (Osteoarthritis Research Society International) score for structural changes of cartilage. The number of tidemarks varied between anatomical regions, respectively, from 4.2 in the medial femoral condyle to 5.0 in the lateral tibial condyle. The axial part showed a significant higher number of tidemarks than the abaxial part, for all regions except the medial tibial condyle. Whilst the tidemark count strongly correlated with age (Spearman's correlation coefficient = 0.70; 95% confidence interval (95% CI): 0.67–0.73; p < 0.0001), the OARSI score was weakly correlated with age in our cohort of sheep (Spearman's correlation coefficient = 0.25; 95% CI: 0.19–0.30; p < 0.0001). Interestingly, no tidemark was seen in the three animals aged 6 months. Our data indicate that the number of tidemarks increases with age and vary with anatomical region. The regional variation also revealed a higher number of tidemarks in the tibia than in the femur. This could be attributed to the local variation in cartilage response to strain and to the difference in chondrocyte biology and density.     

Effects of dietary protein level during rearing period and age at overfeeding on magret and foie gras quality in male mule ducks

The aim of this trial was to study the effects of dietary protein content during the rearing period on the performance of mule ducks, according to age at overfeeding (O). Ducks (n = 612) were divided into four groups differing in the protein content in the diet offered during the starting period (S, 0–20 days; S_l vs. S_h: 150 vs. 175 g/kg crude protein (CP)) and growing‐finishing period (GF; 21–67 or 81 days, depending on age at O; GF_l vs. GF_h: 133 vs. 152 g/kg CP). The relative weight of pectoral muscle was lower when ducks were fed a low protein diet during S (?5%, P < 0.01) or GF period (?6%, P < 0.001) at 68 days and higher in ducks of the S_lGF_h group (+6%; P < 0.05) at 82 days. Both foie gras and magret weights fell when ducks were fed S_l or GF_l (P < 0.05 and < 0.01). Mortality during the O period was higher in ducks fed the S_l diet and overfed at late age (7.4% vs. 0%; P < 0.01). In conclusion, a reduction in the dietary protein supply should be recommended only during the GF period for ducks overfed at a late age.     

Teaching landscape ecology: the importance of field-oriented,inquiry-based approaches

Context

Landscape ecology has traditionally been taught through theoretical classes or computer labs. On the other hand, field labs have been generally less used as a way of teaching landscape ecology concepts.

Objectives

We show that field labs with an inquiry-based approach, where students are involved in the investigation, are feasible for training students in landscape ecology. We evaluated how common field labs are in landscape ecology courses, and also their contribution for student learning.

Methods

We evaluated whether field labs are used in landscape ecology courses by scanning available syllabi. We also used outcomes from a course offered in Brazil to show how field labs can be integrated into landscape ecology courses.

Results

Only 18.2 % of the 44 syllabi we found had field labs. The case study developed in Brazil showed that field labs allowed students to develop important skills, including the ability to design field studies, choose appropriate scales of analysis, detect ecological patterns, and judge multiple hypotheses.

Conclusions

Field labs are still uncommon in landscape ecology courses, but they can be a useful tool to teach landscape ecology concepts and to help students developing the necessary skills to do research. We offer recommendations regarding how to incorporate field labs in landscape ecology courses.

     

Characterization of the structure-activity relationship of kdr and two variants of super-kdr to pyrethroids in the housefly (Musca domestica L.)

Structure-activity relationships (SARs) for 10 pyrethroids against susceptible, kdr and super-kdr strains of houseflies (Musca domestica L.) were investigated by Principal Components Analysis. In the three strains with kdr_Latina' all only slightly to moderately (2.6 to 26-fold) resistant to pyrethroids, no correlation between the structure and Levels of resistance could be discerned. In flies with super-kdr, SARs were influenced by the nature of the alcoholic portion of the ester. Resistance was strongest to esters of a-cyano-3-phenoxybenzyl alcohol (74 to 430-fold) and to permethrin (48 to 55-fold). It was weak (6.2 to 11-fold) to cyclopentenone derivatives, being barely stronger than for flies with kdr (2-6 to 6.3-fold). Two variants of super-kdr (3D and A2) were distinguished on the basis of their differential response to esters of 5-benzyl-3-furylmethanol. It is presumed that kdr_Latina, super-kdr_A2 and super-kdr_3D form an allelic series in which kdr_Latina represents ground level insensitivity, and the two super-kdrs the progressive extension of strong resistance to more types of ester. The strong differences in resistance to different pyrethroid esters by super-kdr flies provides scope for improving management of resistance to pyrethroid insecticides and for modifying the SAR of pyrethroids to favour weak resistance.     

Synthesis of a new class of pyridine herbicide

A new class of fluoroalkylated pyridine herbicides has been discovered. The 3,5-pyridinedicarboxylates are prepared either from ethyl 4,4,4-trifluoroacetoacetate via Hantzsch dihydropyridine synthesis or from trifluoroacetonitrile via cyclocondensation and carboxylation. Hydrolysis of the ester groups, followed by derivatization of the resulting acids yields a variety of herbicidally active analogs including ester, thioester, amide, halogen, amino, alkoxy and alkylthio derivatives.