A replication analysis of foot-and-mouth disease virus in swine lymphoid tissue might indicate a putative carrier stage in pigs

ABSTRACT: Foot-and-mouth disease virus (FMVD), one of the most contagious viruses of cloven-hoofed animals, may cause a prolonged, asymptomatic but persistent infection in ruminants, named the "carrier state". However, it remains an open question whether this carrier state occurs in pigs. Here we present quantitative analyses of the duration of FMDV RNA and infectivity in lymphoid and epithelial tissues in experimentally infected pigs with FMDV C-S8c1. The data indicated that although FMDV RNA remained in blood until day 14 post-infection (pi), viremia was cleared by day 7 pi. However, all tissues tested were positive for FMDV until day 14-17 pi. Interestingly, the specific infectivity of FMDV in these tissues was in some cases even higher than the FMDV C-S8c1. We therefore propose that a "pseudopersistent state" may occur in pigs in which virus replicates in lymphoid tissues for a prolonged period of time, thereby representing a potential source of virus.     

Virulence genes and plasmid profiles in Rhodococcus equi isolates from domestic pigs and wild boars (Sus scrofa) in Brazil

The virulence genes and plasmid profiles of 23 Rhodococcus equi isolates from 258 lymph nodes from domestic pigs (129 nodes with lesions and 129 without lesions) and 120 lymph nodes from slaughtered wild boars (60 nodes with lesions and 60 without) were characterized. R. equi was obtained from 19 lymph nodes of domestic pigs, 17 with, and two without lesions, and from four lymph nodes with lesions, from wild boars. The 23 isolates were tested for the presence of vapA and vapB genes, responsible for the 15–17 and 20 kDa virulence-associated proteins, respectively, by PCR in order to characterize as virulent (VapA), intermediately virulent (VapB) and avirulent. Plasmid DNAs were isolated and analyzed by digestion with restriction endonucleases to estimate size and compare their polymorphisms. Of the 19 domestic pigs strains, seven (36.8%) were avirulent and 12 (63.2%) were intermediately virulent, with the intermediately virulent isolates being plasmid types 8 (8 isolates), 10 (2 isolates), 1 (1 isolate) and 29 (1 isolate). The plasmid type of four strains isolated from wild boars was also intermediately virulent type 8. None of the domestic pigs and wild boar isolates showed the vapA gene. These findings demonstrate a high occurrence of plasmid type 8 in isolates from pigs and wild boars, and the similarity of plasmid types in the domestic pigs, wild boars and human isolates in Brazil.     

Public perceptions of the transmission of pandemic influenza A/H1N1 2009 from pigs and pork products in Australia

A cross-sectional study was conducted at the height of the pandemic influenza H1N1/09 outbreak in Australia in 2009. The objectives of the study were to evaluate public perceptions about transmission and prevention of the disease, to understand their concerns and preparedness to cope with the disease, and to investigate drivers influencing their behaviour. A questionnaire was designed and administered to 510 customers visiting 15 butcher shops in the Greater Sydney region between 26th June and 2nd August 2009. Data were analysed to estimate the proportion of people with certain perceptions and to evaluate the influence of these perceptions on two binary outcome variables: (1) whether or not people believed that avoiding pork would protect them from contracting H1N1/09, and (2) whether or not they actually made some changes to pork consumption after the outbreak. A majority of the respondents had perceptions based on fact about transmission and prevention of H1N1/09. As many as 96.8% of the respondents believed that washing their hands frequently was likely to protect them from contracting H1N1/09. Similarly, most believed that they could contract H1N1/09 by travelling on public transport with a sick person present (94.1%), by shaking hands with a sick person (89.2%), or by attending a community gathering (73.7%). Women were more likely than men to have factual perceptions about protective behaviours. Misconceptions regarding transmission of the disease were evident, with 21.7% believing that avoiding eating pork could protect them against H1N1/09, 11.1% believing that they could contract H1N1/09 by drinking tap water, 22.8% by handling uncooked pork meat and 15.6% by eating cooked pork. Approximately one third of respondents believed that working in a pig farm or an abattoir increased their likelihood of contracting H1N1/09 (36.9% and 32.3%, respectively). Younger people (<35 years old) were more likely to have these misconceptions than older people. Reduction in consumption of pork, ham or bacon was significantly associated with misconceptions regarding the risk of contracting H1N1/09 from eating pig meat products. It is recommended that in the event of a future disease emergency, communication activities providing factual information and targeting younger people should be used.     

Anti-Neospora caninum antibodies in milk in relation to production losses in dairy cattle

A comprehensive field study was carried out with the following objectives: (a) to assess the usefulness of individual and bulk tank milk analysis for determining Neospora caninum serostatus in individual cows and herds, and (b) to study the associations between N. caninum infection status (based on milk testing), and several productive and reproductive parameters in the animals. Antibodies were detected with a commercially available ELISA test (Bio K 192/5). Analysis of paired serum and milk samples from 1134 lactating cows on 38 farms revealed that 97.6% of the ELISA results were coincident, irrespective of whether serum or milk samples were used. Moreover, multiple linear regression analysis revealed that 86.0% of the variations in ELISA values in milk were due to variations in the serum. The measurement of antibodies in bulk tank milk was a good estimator of the herd level status of N. caninum infection, and enabled detection of infection in 94.7% herds with ≥10.0% seropositive cows and/or in all herds with >4% highly seropositive cows. The odds ratio for abortion in seropositive animals was 9.1 times higher than in seronegative animals. The infection serostatus was also a significant risk factor, as the odds ratio for abortion was even higher (12.0 times) in cows categorized as highly seropositive. ELISA values for the bulk milk from 387 randomly selected herds were negatively associated with average milk production. Moreover, milk production losses mainly occurred on farms categorized as highly positive (i.e. herds with ≥20.0% seropositive cows).     

Squamous cell carcinoma of the vagina and cervix in sheep - case report

This report describes the clinical and histopathological characteristics of a squamous cell carcinoma infiltrating the cervix and the vaginal wall, producing reproductive symptoms and subnormal fertility in an adult ewe. Necropsy showed a large (15-cm-long) neoplastic mass infiltrating the vaginal wall and the cervix. Histopathological examination revealed atypical squamous epithelial cords invading the basal membrane and dermis, round anaplastic cells, focal areas of necrosis, keratinisation of isolated cells, and pronounced infiltration by mononuclear cells around the cords. No squamous cell carcinoma of such localisation has been reported from sheep before. In humans, this tumour is the most common gynaecological malignancy in the world.     

In vitro inhibition of Citrobacter freundii, a red-leg syndrome associated pathogen in raniculture, by indigenous Lactococcus lactis CRL 1584

Red-leg syndrome (RLS) is one of the main infectious diseases that cause economic losses in Lithobates catesbeianus hatcheries, Citrobacter freundii being an etiological agent. Treatment or prevention with therapeutics or chemicals results in modifications of the indigenous microbiota, development of antibiotic resistance, presence of their residues in food and enhancement of production costs. Thus, probiotics could be used as an alternative therapy. Lactic acid bacteria are part of the indigenous microbiota of healthy frogs and can prevent pathogen colonization by different mechanisms, including the production of antagonistic substances. In this work, the evaluation and characterization of the inhibition of C. freundii CFb by Lactococcus lactis subsp. lactis CRL 1584, a potentially probiotic candidate, were carried out. This strain produced lactic acid, H(2)O(2) and bacteriocin in static and shaken conditions and inhibited pathogen growth in associative cultures, with an earlier inhibition under agitated conditions. The elimination of each of the antimicrobial metabolites partially abolished the inhibition of the pathogen, suggesting that the inhibitory effect could be attributed to a combined action of the three antagonistic molecules. Electron microphotographs revealed the damage caused by L. lactis CRL 1584 supernatants to C. freundii cells. The addition of pure lactic acid, H(2)O(2) and bacteriocin to the culture media showed that each metabolite caused different morphological modifications in C. freundii, in agreement with the effect on viable cell counts. The results support the possibility that L. lactis CRL 1584 might be considered as a probiotic to be used in the prevention of RLS in raniculture.     

Growth and development of pepper are affected by humic substances derived from composted sludge

A greenhouse experiment was conducted to evaluate the effects of humic substances extracted from composted sewage sludge on growth, phenological development, and photosynthetic activity of pepper (Capsicum annuum L. cv. Piquillo) plants. Humic substances derived from composted sludge (HSS) were compared with those derived from leonardite (HSL). Two doses of both humic substances were assayed (200 and 500 mg C [L substrate]^–1) and compared with a control (C). HSS showed higher nitrogen content and a higher percentage of aliphatic carbon, as well as a lower content of aromatic and phenolic carbon than HSL. HSS significantly increased plant dry‐matter production (up to 560%), plant height (86%–151%), and leaf area (436%–1397%) during the early stages of pepper development. Net photosynthesis and stomatal conductance increased in the treatments with HSS (up to 48% and 63%, respectively) at the vegetative stage. In addition, HSS accelerated the phenological development of pepper plants, reducing significantly the number of days to flowering and ripening, which occurred 12 and 14 d earlier than in control plants, respectively. In general, the treatments with HSS and HSL did not markedly affect chlorophyll and nutrient concentrations in the leaves. At maturity, only small differences in total fruit yield, number of fruits per plant, and fruit size were observed between amended and control plants. The results suggest that the mechanisms through which HSS affected plant growth and development were not associated with an improved nutrient uptake. Although the identity of the growth‐promoting factors remains to be found, the results suggest that they may be linked to the chemical structure of the humic substances.     

Levels of 131I and Six Natural Radionuclides in Sludge from the Sewage Treatment Plant of Valladolid, Spain

The levels of ¹³¹I and six natural radionuclides (²³⁸U, ²²⁶Ra, ²¹⁰Pb, ²²⁸Ra, ²²⁴Ra, and ⁴⁰K) were determined in sewage sludge samples obtained from an urban wastewater treatment plant that services a medium-sized town in Spain. Secondary treatment of wastewater consisting of anaerobic, anoxic, and oxic stages is collectively called A2O processing. Radio analytical determinations were performed by gamma spectrometry using a high-purity germanium detector. This technique has proven useful in identifying local radioactive pollution. This type of pollution was consistently detected throughout the year, with several increases associated with authorized discharges from hospitals. Finally, we examined the radiation dose that workers are exposed to due to the presence of ¹³¹I in the sludge. We found inhalation risk to be negligible, with external radiation as the main source of exposure to ¹³¹I.