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.     

The cytologic and histologic diagnosis of ureteral fibroepithelial polyp in a dog

A 6-year-old, intact male, brindled, 30-Lb English Bulldog presented to the Purdue University Veterinary Teaching Hospital with a recurrent history of hematuria, periuria, and lethargy that responded temporarily to antibiotic therapy. The work-up included a complete blood count, serum biochemical profile, complete urinalysis, diagnostic imaging (abdominal radiographs and ultrasound with contrast urography), and exploratory laparotomy. The diagnostic imaging findings and subsequent exploratory revealed a unilateral, intraluminal, right-sided, 3-cm ureteral mass extending from the proximal ureter into the renal pelvis. Subsequently, a unilateral right-sided ureteronephrectomy followed by biopsy with cytopathology/cytology (impression smears) and histopathology of the ureteral mass was performed. The cytopathologic interpretation was benign mesenchymal proliferation with mildly atypical urothelial cells. The association of this mass with vascular tissue and a benign nuclear appearance on cytology is similar to reports of fibroepithelial polyps (FEPs) and myxomatous tumors. Histopathology diagnosed the mass as an FEP. Cytopathology proved useful in the presumptive diagnosis of this benign urothelial polyp. To the authors' knowledge, this is the first report using cytopathology to depict and characterize FEPs in veterinary and human medical literature.     

Reducing gaseous nitrogen loss from stored laying hen manure by the addition of carbohydrates

Three separate experiments were conducted to determine if the addition of carbohydrate sources directly to freshly-produced laying hen manure reduced the loss of gaseous nitrogen containing compounds during 7 d of storage. The addition of sucrose (8 g/kg) to the manure resulted in a greater increase in bacterial numbers, a greater loss of carbon and a trend for a reduced loss of nitrogen. Although glucose addition to the manure increased bacterial numbers and tended to increase carbon loss, nitrogen loss increased relative to the control. Addition of straw to the manure did not affect the change in bacterial numbers or rate of nitrogen loss compared to the control treatment. Experiment 2 indicated that, when either sucrose or maltose were mixed (8 g/kg) with laying hen manure, microbial numbers were increased and gaseous nitrogen losses were reduced. A combination of starch plus alpha-amylase did not affect the characteristics of the manure. Experiment 3 showed that increasing sucrose addition gave a non-linear reduction in nitrogen loss. Minimum nitrogen loss was obtained with 35 g/kg sucrose, though the maximum increase in bacterial numbers occurred at 20 g/kg of added sucrose.     

Determining resistance to <Emphasis Type="Italic">Fusarium verticillioides</Emphasis> and fumonisin accumulation in African maize inbred lines resistant to <Emphasis Type="Italic">Aspergillus flavus</Emphasis> and aflatoxins

Fusarium verticillioides and Aspergillus flavus cause Fusarium ear rot (FER) and Aspergillus ear rot (AER) of maize, respectively. Both pathogens are of concern to producers as they reduce grain yield and affect quality. F. verticillioides and A. flavus also contaminate maize grain with the mycotoxins fumonisins and aflatoxins, respectively, which has been associated with mycotoxicosis in humans and animals. The occurrence of common resistance mechanisms to FER and AER has been reported. Hence, ten Kenyan inbred lines resistant to AER and aflatoxin accumulation were evaluated for resistance to FER, F. verticillioides colonisation and fumonisin accumulation; and compared to nine South African lines resistant to FER and fumonisin accumulation. Field trials were conducted at three localities in South Africa and two localities in Kenya. FER severity was determined by visual assessment, while F. verticillioides colonisation and fumonisin content were quantified by real-time PCR and liquid chromatography tandem mass spectrometry, respectively. Significant genotype x environment interactions was determined at each location (P ≤ 0.05). Kenyan inbred CML495 was most resistant to FER and F. verticillioides colonisation, and accumulated the lowest concentration of fumonisins across localities. It was, however, not significantly more resistant than Kenyan lines CML264 and CKL05015, and the South African line RO549 W, which also exhibited low FER severity (≤5%), fungal target DNA (≤0.025 ng μL^?1) and fumonisin levels (≤2.5 mg kg^?1). Inbred lines resistant to AER and aflatoxin accumulation appear to be promising sources of resistance to F. verticillioides and fumonisin contamination.