Definition, willingness-to-pay, and ranking of quality attributes of U.S. pork as defined by importers in Asia and Mexico.

A survey was conducted from November 2009 to April 2010 to determine how importers of pork define 7 predetermined quality categories (food safety, customer service, eating quality, product specification, packaging, visual characteristics, and production history) and to estimate willingness-to-pay (WTP) and establish best-worst (B/W) scaling (rank) for the 7 quality categories. Interviews were conducted in Hong Kong/China (n = 83), Japan (n = 48), Mexico (n = 70) and Russia (n = 54) with importers of U.S. pork or those who had purchased U.S. pork from distributors in the last 3 yr. Interviews used dynamic routing software and were structured such that economic factors for purchase were addressed first, allowing all responses to focus on quality. Questions about WTP and B/W were asked and then each respondent was asked to define what each quality category meant to them. Generalized linear mixed models were used to analyze frequency data. Over 70% of interviewees in Hong Kong/China, Japan, and Mexico responded that purchase price was influential in deciding whether or not to purchase imported pork. This number was lower in Russia, where respondents stated tariff rates were also important, indicating market access was a larger issue in Russia. Food safety was the most important quality category (price was not included as a part of quality) for imported pork followed by specifications. Respondents indicated some form of government inspection was how they defined food safety, whereas product size, weight, and subcutaneous fat were all included in the definition of specifications. Interviewees were more likely to pay premiums for customer service and less likely to pay premiums for packaging (P < 0.05). The premiums that were willing to be paid for guarantees of quality for imported pork variety meats were numerically lower than for whole muscle cuts or processed products. A guarantee associated with food safety of processed pork products was found to be the quality attribute for which importers would be willing to pay the highest premium. Production history was found to be the least important quality attribute for importers of all types of U.S. pork, except those in Japan. Exporters could increase profitability if a guarantee of customer service was made. Price, tariffs, and exchange rates are important to pork importers; these results indicated that if certain quality attributes could be guaranteed, exporters could increase profitability.

Prevalence and co-infection of Toxoplasma gondii and Neospora caninum in Apodemus sylvaticus in an area relatively free of cats.

The protozoan parasite Toxoplasma gondii is prevalent worldwide and can infect a remarkably wide range of hosts despite felids being the only definitive host. As cats play a major role in transmission to secondary mammalian hosts, the interaction between cats and these hosts should be a major factor determining final prevalence in the secondary host. This study investigates the prevalence of T. gondii in a natural population of Apodemus sylvaticus collected from an area with low cat density (<2·5 cats/km2). A surprisingly high prevalence of 40·78% (95% CI: 34·07%-47·79%) was observed despite this. A comparable level of prevalence was observed in a previously published study using the same approaches where a prevalence of 59% (95% CI: 50·13%-67·87%) was observed in a natural population of Mus domesticus from an area with high cat density (>500 cats/km2). Detection of infected foetuses from pregnant dams in both populations suggests that congenital transmission may enable persistence of infection in the absence of cats. The prevalences of the related parasite, Neospora caninum were found to be low in both populations (A. sylvaticus: 3·39% (95% CI: 0·12%-6·66%); M. domesticus: 3·08% (95% CI: 0·11%-6·05%)). These results suggest that cat density may have a lower than expected effect on final prevalence in these ecosystems.

Evidence for high levels of vertical transmission in Toxoplasma gondii.

Toxoplasma gondii is a highly ubiquitous and prevalent parasite. Despite the cat being the only definitive host, it is found in almost all geographical areas and warm blooded animals. Three routes of transmission are recognised: ingestion of oocysts shed by the cat, carnivory and congenital transmission. In natural populations, it is difficult to establish the relative importance of these routes. This paper reviews recent work in our laboratory which suggests that congenital transmission may be much more important than previously thought. Using PCR detection of the parasite, studies in sheep show that congenital transmission may occur in as many as 66% of pregnancies. Furthermore, in families of sheep on the same farm, exposed to the same sources of oocysts, significant divergent prevalences of Toxoplasma infection and abortion are found between different families. The data suggest that breeding from infected ewes increases the risk of subsequent abortion and infection in lambs. Congenital transmission rates in a natural population of mice were found to be 75%. Interestingly, congenital transmission rates in humans were measured at 19.8%. The results presented in these studies differ from those of other published studies and suggest that vertical transmission may be much more important than previously thought.

Molecular characterisation of the recA locus in clinical isolates of verocytotoxigenic E. coli O157:H7.

Molecular epidemiology of verocytoxigenic Escherichia coli O157:H7 is important to help elucidate reservoirs and modes of transmission, particularly between animals and humans. As the recA gene locus is now beginning to gain application in bacterial genotyping schemes, and as it has not been examined previously in E. coli O157 isolates, this study aims to examine potential polymorphic variation as a possible epidemiological marker for the subspecies characterisation of clinically significant verocytotoxigenic E. coli O157:H7. A novel polymerase chain reaction (PCR) assay was designed to target a 638 bp region of the recA gene in E. coli O157 isolates. The PCR amplification of genomic DNA from extracted organisms was able to generate an amplicon of the expected size (approximately 638 bp) for all E. coli O157:H7 examined (n=80), as well as for other non-O157 E. coli and other members of the Enterobacteriaeceae including Citrobacter, Hafnia, Shigella, Enterobacter and Providencia. Subsequent restriction fragment length polymorphism (RFLP) and single-stranded conformational polymorphism (SSCP) analyses of these recA amplicons were able to differentiate E. coli O157 from the organisms examined, but were unable to distinguish between 79 isolates of wild-type E. coli O157, suggesting a highly conserved recA gene structure within the local population of organisms examined.

Alkaline hydrolysis of mouse-adapted scrapie for inactivation and disposal of prion-positive material.

Prion diseases such as bovine spongiform encephalopathy, chronic wasting disease, and scrapie pose serious risks to human and animal health due to a host of disease-specific factors, including the resistance of infectious prions (PrP(Sc)) to natural degradation and to most commercial inactivation procedures. In an attempt to address this concern, a mouse model was used to compare the efficacy of an alkaline hydrolysis process with a simulated continuous-flow rendering treatment for disposal of PrP(Sc)-infected biological material. Female C57/BL6 mice (N = 120) were randomly divided into 4 treatment groups (n = 30), and each mouse was injected intraperitoneally with their designated treatment inoculum. Treatment groups 1 and 2 served as the positive and negative controls, respectively. Group 3 was inoculated with rendered scrapie-positive mouse brain material to investigate the effectiveness of simulated continuous-flow rendering practices to reduce or eliminate PrP(Sc). Group 4 was inoculated with hydrolyzed scrapie-positive mouse brain material to determine the sterilizing effect of alkaline hydrolysis on PrP(Sc). Mice were monitored for overt signs of disease, and those showing clinical signs were killed to prevent undue suffering. Brains were obtained from all mice that died (or were killed) and analyzed with an ELISA for the presence of PrP(Sc). Results indicated that the simulated continuous-flow rendering treatment used for preparing the rendering treatment group inoculum failed to completely eliminate PrP(Sc). Rendering delayed, but did not stop, clinical mouse-adapted scrapie transmission. Compared with positive controls, the rendering treatment group experienced an approximate 45-d average delay in days to death (250 vs. 205 d for positive controls; P < 0.0001) and a death loss of 73.9% (P = 0.0094). Positive controls suffered 100% death loss. The results validated the efficacy of the alkaline hydrolysis treatment to inactivate all PrP(Sc) because no alkaline hydrolysis treatment group mice succumbed to the disease (P < 0.0001). Based on our results, alkaline hydrolysis should be considered by the animal rendering and beef packing industries as an alternative to incineration, landfill burial, and rendering for disposing of biological material potentially infected or contaminated with prion disease.

Molecular epidemiology of Pseudomonas aeruginosa in adult patients with cystic fibrosis in Northern Ireland.

Isolates (n = 51) of Pseudomonas aeruginosa obtained from the sputa of 29 adult patients attending the Regional Cystic Fibrosis Centre in Northern Ireland were compared using an enterobacterial repetitive intergenic consensus sequence (ERIC2) primer in a random amplification of polymorphic DNA (RAPD) polymerase chain reaction (PCR) method. Resulting banding patterns showed a high degree of genetic heterogeneity among all isolates from the patients examined, suggesting a non-clonal relationship between isolates from these patients, when employing this genotyping technique.

The prevalence of Neospora caninum and co-infection with Toxoplasma gondii by PCR analysis in naturally occurring mammal populations.

Neospora caninum and Toxoplasma gondii are closely related intracellular protozoan parasites associated with bovine and ovine abortion respectively. Little is known about the extent of Neospora/Toxoplasma co-infection in naturally infected populations of animals. Using nested PCR techniques, based on primers from the Nc5 region of N. caninum and SAG1 for T. gondii, the prevalence of N. caninum and its co-infection with T. gondii were investigated in populations of Mus domesticus, Rattus norvegicus and aborted lambs (Ovis aries). A low frequency of infection with N. caninum was detected in the Mus domesticus (3%) and Rattus norvegicus (4.4%) populations. A relatively high frequency of infection with N. caninum was detected in the brains of aborted lambs (18.9%). There was no significant relationship between N. caninum and T. gondii co-infection. Investigation of the tissue distribution of Neospora, in aborted lambs, showed that Neospora could not be detected in tissues other than brain and this was in contrast to Toxoplasma where the parasite could be frequently detected in a range of tissues.

Detection of high levels of congenital transmission of Toxoplasma gondii in natural urban populations of Mus domesticus.

The relative importance of different transmission routes of Toxoplasma gondii has been a matter for debate. This ubiquitous parasite is generally thought to be transmitted by infective oocysts excreted by the definitive host, the cat. Ingestion of undercooked meat has also been considered an important route of transmission in many mammals while congenital transmission has generally been considered relatively rare. Experimental studies demonstrate the ability of T. gondii to be transmitted congenitally, but few studies have investigated the frequency of this transmission route in natural populations. We use PCR amplification of the SAG1 gene to investigate the frequency of congenital transmission in a wild population of mice (Mus domesticus) and show that congenital transmission is occurring in 75% of pregnancies in this population. Furthermore, for infected pregnant mice, transmission occurs to at least one foetus in 100% of cases while variable penetrance of congenital infection is observed. These high levels of congenital transmission in this wild population of mice, taken together with other recent data on congenital transmission in sheep, suggests that this phenomenon might be more widespread than previously thought.

Osteonecrosis in pediatric patients with acute lymphoblastic leukemia.

The authors report five pediatric patients with acute lymphoblastic leukemia (ALL) in whom symptomatic aseptic osteonecrosis developed on therapy. All patients had been on treatment with a modified BFM protocol and developed osteonecrosis in the maintenance phase of the protocol. The avascular necrosis was multifocal in all. The authors' data suggest that dexamethasone used in the reinduction phase of the protocol may be the responsible agent although no definite proof exists. Since only symptomatic patients are reported, the true frequency of this complication may be significantly higher.

Osteomyelitis in pediatric patients with leukemia.

An 11-year retrospective study showed that there were nine patients with osteomyelitis in our population of pediatric patients with leukemia. Six patients had acute lymphoblastic leukemia (ALL) and three had acute nonlymphoblastic leukemia (ANLL). Seven of nine patients were in remission at the time of diagnosis of osteomyelitis. The delay in diagnosis, which exceeded 2 weeks in seven patients, was typical. Surgical intervention was required for diagnostic or therapeutic purposes in five patients. Staphylococcus aureus was isolated from only three patients. Informative diagnostic studies included nuclear scans that yielded abnormal results in all patients and erythrocyte sedimentation rates (ESR) that were elevated to greater than 70 mm/h in seven patients. The recognition of features that differ from osteomyelitis in the normal population may facilitate earlier diagnosis.

Graft infection and bacteremia with Listeria monocytogenes in a patient receiving hemodialysis.

Patients receiving hemodialysis are particularly susceptible to infection. We report a case of Listeria monocytogenes bacteremia and graft infection developing in a patient receiving hemodialysis. Vancomycin hydrochloride therapy was initiated in anticipation of a staphylococcal infection, and continued as the patient's clinical course improved. Ultimately the arteriovenous graft required excision. Identification of the organism and drug susceptibilities are described. To our knowledge, this is the first case report of both an L monocytogenes arteriovenous graft infection and the use of vancomycin in the treatment of this infection.