Ecological impacts of small hydropower plants on headwater stream fish: from individual to community effects

Hydroelectricity is increasingly used worldwide as a source of renewable energy, and many mountain ranges have dozens or hundreds of hydropower plants, with many more being under construction or planned. Although the ecological impacts of large dams are relatively well known, the effects of small hydropower plants and their weirs have been much less investigated. We studied the effects of water diversion of small hydropower plants on fish assemblages in the upper Ter river basin (Catalonia, NE Spain), which has headwater reaches with good water quality and no large dams but many of such plants. We studied fish populations and habitat features on control and impacted reaches for water diversion of 16 hydropower plants. In the impacted reaches, there was a significantly lower presence of refuges for fish, poorer habitat quality, more pools and less riffles and macrophytes, and shallower water levels. We also observed higher fish abundance, larger mean fish size and better fish condition in the control than in impacted reaches, although the results were species‐specific. Accordingly, species composition was also affected, with lower relative abundance of brown trout (Salmo trutta) and Pyrenean minnow (Phoxinus bigerri) in the impacted reaches and higher presence of stone loach (Barbatula quignardi) and Mediterranean barbel (Barbus meridionalis). Our study highlights the effects of water diversion of small hydropower plants from the individual to the population and community levels but probably underestimates them, urging for further assessment and mitigation of these ecological impacts.     

No evidence for avoidance of black rat scent by the presumably less competitive Natal multimammate mouse in a choice experiment

In Africa, indigenous multimammate mice (Mastomys natalensis) only appear to live commensally in houses when invasive black rats (Rattus rattus) are absent, yet little is known about the underlying mechanism. Avoidance through smell may cause the absence of M. natalensis from areas occupied by R. rattus, but this hypothesis has not yet been tested. We conducted a Y-maze choice experiment where 15 M. natalensis were offered a choice between corridors containing conspecific scent, R. rattus scent and a control scent. Residence time in the R. rattus corridor was greater than that in the control corridor but equal to that in the M. natalensis corridor, suggesting that multimammate mice do not actively avoid the scent of their invasive competitor.     

New histochemical and ultrastructural observations on normal bovine tonsils.

Samples of normal bovine palatine tonsils were examined by light and electron microscopy. Like human tonsils, they were composed of crypts, subepithelial areas, follicles, and T-dependent zones, but their well-developed capsule subdivided the lymphoid tissue by connective septa. B cells formed the major lymphoid component. The follicles and T-dependent zones had morphological and histochemical features typical of peripheral lymph organs. Follicular dendritic cells were isolated and shown to be similar to human follicular dendritic cells.     

Sites of fixation of Amblyomma variegatum ticks on their hosts in Guadeloupe (French west Indies)]

The examination of 458 domestic and wild hosts of the tick A. variegatum allowed to collect 8,581 larvae, 646 nymphs, 685 adults in 9 different animal species and to determine their preferential attachment sites. In another survey on 15 goats and 5 cattle, 12,345 larvae, 2,111 nymphs and 4,625 adults were counted on the anatomic sites. Immature ticks feed preferentially on the head, neck and limbs of birds, the limbs of mongoose and the limbs and ears of dogs, goats and cattle. Adults feed only on hosts of medium to large size and attach on ventral parts of the body, especially the groin, perineum, axillae and the dewlap of cattle. This tick species should be searched for on these sites when estimating its propagation in a threatened area or the evolution of its population during an eradication campaign. Moreover, the acaricide concentration on these sites must be optimal during systematic treatments.     

Temporal-spatial epidemiology of foot-and-mouth disease outbreaks in Mongolia, 2000 – 2002

Prior to 2000, foot-and-mouth disease (FMD) had not been observed in Mongolia since 1973; however, between April 2000 and July 2002, Mongolia reported 44 FMD outbreaks that affected cattle, sheep, goats, and camels. The objectives of this study were to describe the distributions of the 44 reported FMD outbreaks in Mongolia and to assess their spatial clustering and directions of movement. Official reports were collected to obtain the number and species of animals both affected and at risk, and the date and geographical coordinates of each outbreak. Significant global and local spatial clusters of reported FMD outbreaks were identified. Disease spread during the second epidemic moved 76° northeast and the spread of the disease during the third epidemic moved 110° northwest. FMD outbreaks were clustered intensely close to other FMD-positive counties. These findings can be used in the future to help plan prevention and control measures in high risk areas.     

EFFICACY AND TOXICITY OF AN ACCELERATED HYPOFRACTIONATED RADIATION THERAPY PROTOCOL IN CATS WITH ORAL SQUAMOUS CELL CARCINOMA

Squamous cell carcinoma (SCC) is the most common feline oral tumor. Standard radiation protocols have been reported to achieve tumor control durations of 1.5–5.5 months (45–165 days). The purpose of this study was to describe the efficacy and toxicity of an accelerated hypofractionated radiation therapy protocol in cats with oral SCC. Twenty‐one cats with histologically confirmed oral SCC and T1‐3N0M0 were treated with 10 once‐daily fractions (Monday–Friday) of 4.8 Gy. Seventeen cats had macroscopic disease and four were microscopic after incomplete excision. Acute toxicity consisted of grade 2 mucositis in all cats and this was effectively managed using esophageal or gastric tube feeding, pain medication, and antibiotics. Late toxicity effects for cats with available follow‐up data included alopecia (4 cats), leukotricia (6), tongue ulceration (1), and oronasal fistula (1). Response could be assessed in 17 cats (seven complete response and five partial response). Four cats (19%) developed metastatic disease without evidence of local progression. The median progression‐free survival (PFS) was 105 days (1 year PFS of 23%), median local progression‐free survival (LPFS) was 219 days (1 year LPFS of 41%), and median overall survival (OS) was 174 days (1 year OS of 29%). Only tumor stage was prognostic, with T1 having a median PFS of 590 days. Findings indicated that this accelerated hypofractionated radiation therapy protocol was well tolerated in cats with oral SCC, with manageable adverse events. Tumor response was observed in most cats and long tumor control durations were achieved in some cats.     

Dynamics of influenza A virus infections in permanently infected pig farms: evidence of recurrent infections,circulation of several swine influenza viruses and reassortment events

Concomitant infections by different influenza A virus subtypes within pig farms increase the risk of new reassortant virus emergence. The aims of this study were to characterize the epidemiology of recurrent swine influenza virus infections and identify their main determinants. A follow-up study was carried out in 3 selected farms known to be affected by repeated influenza infections. Three batches of pigs were followed within each farm from birth to slaughter through a representative sample of 40 piglets per batch. Piglets were monitored individually on a monthly basis for serology and clinical parameters. When a flu outbreak occurred, daily virological and clinical investigations were carried out for two weeks. Influenza outbreaks, confirmed by influenza A virus detection, were reported at least once in each batch. These outbreaks occurred at a constant age within farms and were correlated with an increased frequency of sneezing and coughing fits. H1N1 and H1N2 viruses from European enzootic subtypes and reassortants between viruses from these lineages were consecutively and sometimes simultaneously identified depending on the batch, suggesting virus co-circulations at the farm, batch and sometimes individual levels. The estimated reproduction ratio R of influenza outbreaks ranged between 2.5 [1.9-2.9] and 6.9 [4.1-10.5] according to the age at infection-time and serological status of infected piglets. Duration of shedding was influenced by the age at infection time, the serological status of the dam and mingling practices. An impaired humoral response was identified in piglets infected at a time when they still presented maternally-derived antibodies.     

Update on the diagnosis of Haemophilus parasuis infection in pigs and novel genotyping methods

Haemophilus parasuis causes Gl?sser's disease as well as a number of other diseases in pigs. The diagnosis of H. parasuis-associated disease is usually established by clinical signs, pathological findings and bacterial isolation but diagnosis is complicated by the existence of non-virulent strains and the early colonisation of the upper respiratory tract of healthy piglets. Moreover, several strains can be found on a farm and even within a single animal so it is important to determine the specific strain that is causing the clinical outbreak. Recently, genotyping methods have been developed with the goal of correlating genotype with the degree of virulence of H. parasuis strains. The association between genotype and virulence in H. parasuis is challenging due to the lack of knowledge of the complete genomic sequence and virulence factors of this bacterium.