Examining the effects of prenatal alcohol exposure on performance of the sustained attention to response task in children with an FASD.

Prenatal alcohol exposure (PAE), the leading known cause of childhood developmental disability, has long-lasting effects extending throughout the lifespan. It is well documented that children prenatally exposed to alcohol have difficulties inhibiting behavior and sustaining attention. Thus, the Sustained Attention to Response Task (SART), a Go/No-go paradigm, is especially well suited to assess the behavioral and neural functioning characteristics of children with PAE. In this study, we utilized neuropsychological assessment, parent/guardian questionnaires, and magnetoencephalography during SART random and fixed orders to assess characteristics of children 8-12 years old prenatally exposed to alcohol compared to typically developing children. Compared to neurotypical control children, children with a Fetal Alcohol Spectrum Disorder (FASD) diagnosis had significantly decreased performance on neuropsychological measures, had deficiencies in task-based performance, were rated as having increased Attention-Deficit/Hyperactivity Disorder (ADHD) behaviors and as having lower cognitive functioning by their caretakers, and had decreased peak amplitudes in Broadmann's Area 44 (BA44) during SART. Further, MEG peak amplitude in BA44 was found to be significantly associated with neuropsychological test results, parent/guardian questionnaires, and task-based performance such that decreased amplitude was associated with poorer performance. In exploratory analyses, we also found significant correlations between total cortical volume and MEG peak amplitude indicating that the reduced amplitude is likely related in part to reduced overall brain volume often reported in children with PAE. These findings show that children 8-12 years old with an FASD diagnosis have decreased amplitudes in BA44 during SART random order, and that these deficits are associated with multiple behavioral measures.

Open-reading-frame sequence tags (OSTs) support the existence of at least 17,300 genes in C. elegans.

The genome sequences of Caenorhabditis elegans, Drosophila melanogaster and Arabidopsis thaliana have been predicted to contain 19,000, 13,600 and 25,500 genes, respectively. Before this information can be fully used for evolutionary and functional studies, several issues need to be addressed. First, the gene number estimates obtained in silico and not yet supported by any experimental data need to be verified. For example, it seems biologically paradoxical that C. elegans would have 50% more genes than Drosophilia. Second, intron/exon predictions need to be tested experimentally. Third, complete sets of open reading frames (ORFs), or "ORFeomes," need to be cloned into various expression vectors. To address these issues simultaneously, we have designed and applied to C. elegans the following strategy. Predicted ORFs are amplified by PCR from a highly representative cDNA library using ORF-specific primers, cloned by Gateway recombination cloning and then sequenced to generate ORF sequence tags (OSTs) as a way to verify identity and splicing. In a sample (n=1,222) of the nearly 10,000 genes predicted ab initio (that is, for which no expressed sequence tag (EST) is available so far), at least 70% were verified by OSTs. We also observed that 27% of these experimentally confirmed genes have a structure different from that predicted by GeneFinder. We now have experimental evidence that supports the existence of at least 17,300 genes in C. elegans. Hence we suggest that gene counts based primarily on ESTs may underestimate the number of genes in human and in other organisms.

Examining the effects of prenatal alcohol exposure on corticothalamic connectivity: A multimodal neuroimaging study in children.

Children with a fetal alcohol spectrum disorder (FASD) experience a range of cognitive and behavioral effects. Prior studies have demonstrated white matter changes in children with FASD relative to typically developing controls (TDC) and these changes relate to behavior. Our prior MEG study (Candelaria-Cook et al. 2020) demonstrated reduced alpha oscillations during rest in FASD relative to TDC and alpha power is correlated with behavior. However, little is known about how brain structure influences brain function. We hypothesized that alpha power was related to corticothalamic connectivity. Children 8-13 years of age (TDC: N = 25, FASD: N = 24) underwent rest MEG with eyes open or closed and MRI to collect structural and diffusion tensor imaging data. MEG spectral analysis was performed for sensor and source data. We estimated mean fractional anisotropy in regions of interest (ROIs) that included the corticothalamic tracts. The FASD group had reduced mean FA in three of the corticothalamic ROIs. FA in these tracts was significantly correlated with alpha power at the sensor and source level. The results support the hypothesis that integrity of the corticothalamic tracts influences cortical alpha power. Further research is needed to understand how brain structure and function influence behavior.

Saturation mutagenesis of the yeast his3 regulatory site: requirements for transcriptional induction and for binding by GCN4 activator protein.

Expression of the yeast his3 and other amino acid biosynthetic genes is induced during conditions of amino acid starvation. The coordination of this response is mediated by a positive regulatory protein called GCN4, which binds specifically to regulatory sites upstream of all coregulated genes and stimulates their transcription. The nucleotide sequence requirements of the his3 regulatory site were determined by analysis of numerous point mutations obtained by a novel method of cloning oligonucleotides. Almost all single base pair mutations within the nine base pair sequence ATGACTCTT significantly reduce his3 induction in vivo and GCN4 binding in vitro, whereas changes outside this region have minimal effects. One mutation, which generates a sequence that most closely resembles the consensus for 15 coregulated genes, increases both the level of induction and the affinity for GCN4 protein. The palindromic nature of the optimal sequence, ATGACTCAT, suggest that GCN4 protein binds as a dimer to adjacent half-sites that possibly overlap.

Survival of North American genotypes of Trichinella in frozen pork.

North American genotypes of Trichinella spiralis (T-1), Trichinella nativa (T-2), Trichinella pseudospiralis (T-4), Trichinella murrelli (T-5), and Trichinella T-6 were examined for susceptibility to freezing in pork using time-temperature combinations that have been proven to inactivate T. spiralis. Infections were established in 3-month-old pigs of mixed sex and breed by oral inoculation of 10,000 muscle larvae (ML) (all genotypes, rodent-derived ML), 20,000 ML (T-1, T-4, and T-5; cat-derived ML), or 30,000 ML (T-2 and T-6; cat-derived ML). Pigs were euthanized 60 days postinoculation. Muscles from the tongue, masseter muscles, diaphragm, triceps, hams, neck, rump, and loins were ground, pooled, and mixed to ensure even distribution of larvae. Samples (20 g) containing each Trichinella species, genotype, and source combination were placed in heat-sealable pouches, transferred to a constant temperature refrigerant bath, and maintained according to defined time and temperature combinations. Larvae recovered from cold-treated pork samples were inoculated into mice to determine infectivity. Results indicated that the time-temperature combinations known to render pork safe for T. spiralis are sufficient to inactivate T. nativa and T-6 (the freeze-resistant isolates), T. murrelli (the most common sylvatic species in the United States excluding Alaska), and T. pseudospiralis (a species that lacks a muscle nurse cell). These data close a gap in knowledge about the effectiveness of freezing for inactivating these parasites in pork and should alleviate concern about the safety of frozen pork products from the United States.

Low salt exposure results in inactivation of Toxoplasma gondii bradyzoites during formulation of dry cured ready-to-eat pork sausage.

The production of safe and healthy food products represents one of the main objectives of the food industry. The presence of microorganisms in meat and products containing meat can result in a range of human health problems, as well as economic losses to producers of these products. However, contaminated meat products continue to initiate serious and large-scale outbreaks of disease in consumers. In addition to outbreaks of diseases caused by bacteria and viruses, parasitic organisms, such as Toxoplasma gondii, are responsible for foodborne infections worldwide, and in the case of T. gondii, is considered the 2nd leading cause of death from foodborne illness in the U.S. Transmission of Toxoplasma gondii has historically been linked to the consumption of raw or undercooked meat products, including pork. Specific concerns with respect to pork products are ready-to-eat (RTE) pork meals. These are pork or products containing pork that are prepared by curing or drying, and are not intended to be cooked before being consumed. Previous studies have demonstrated that T. gondii is inactivated during dry cured sausage preparation, apparently in the batter during fermentation. In this study, we have analyzed timing of inactivation of T. gondii in freshly prepared pepperoni batter to confirm our previous findings, to determine how quickly inactivation occurs during fermentation, and to confirm what parameters of the sausage preparation are involved in inactivation of the parasite. Results from the current and previous study indicate that rapid inactivation of T. gondii bradyzoites occurs in low salt batter for dry cured sausage within 4 h of initiation of fermentation.

Toxoplasma gondii tissue cyst formation and density of tissue cysts in shoulders of pigs 7 and 14 days after feeding infected mice tissues.

Among the meat sources of Toxoplasma gondii, pork is considered important in the epidemiology of toxoplasmosis in the USA. How soon after infection T. gondii forms tissue cysts in pork is unknown. In the present study, eight serologically negative ˜3 months old pigs were fed mouse tissues infected with VEG (Type III) strain of T. gondii and euthanized 7 (4 pigs) and 14 days (4 pigs) post-inoculation (p.i.). Meat from the right shoulder of each pig was bioassayed in mice for T. gondii tissue cysts by peptic digestion. From each pig, the shoulder muscle was cut at random spots into 5 g, 10 g and 50 g portions. Extreme care was taken to use different scalpels and forceps to minimize cross contamination among 17 samples (6 replicates of each 5 g and 10 g portions and 5 replicates of 50 g). From the four pigs euthanized at 7 days p.i., a composite of ˜200 g of leftover meat from each shoulder was bioassayed in cats and their feces were tested for oocyst excretion. All eight pigs developed T. gondii antibodies (modified agglutination test, MAT, 1: 80 or higher) and viable T. gondii was isolated from shoulder meat of each pig. All four cats fed pork from excreted T. gondii oocysts. The density of T. gondii, based on mouse infectivity, varied within 5-50 g samples each pig, and between pigs within the same group, day 7 versus day 14 p.i. There were no significant differences in mouse bioassay results obtained with day 7 versus day 14 infected pigs. Overall, the rate of isolation of T. gondii increased with sample size of meat bioassayed. Results demonstrate that tissue cysts are formed early in infection and they are unevenly distributed.

Complete validation of a unique digestion assay to detect Trichinella larvae in horse meat demonstrates the reliability of this assay for meeting food safety and trade requirements.

A tissue digestion assay using a double separatory funnel procedure for the detection of Trichinella larvae in horse meat was validated for application in food safety programs and trade. The assay consisted of a pepsin-HCl digestion step to release larvae from muscle tissue and two sequential sedimentation steps in separatory funnels to recover and concentrate larvae for detection with a stereomicroscope. With defined critical control points, the assay was conducted within a quality assurance system compliant with International Organization for Standardization-International Electrotechnical Commission (ISO/IEC) 17025 guidelines. Samples used in the validation were obtained from horses experimentally infected with Trichinella spiralis to obtain a range of muscle larvae densities. One-, 5-, and 10-g samples of infected tissue were combined with 99, 95, and 90 g, respectively, of known negative horse tissue to create a 100-g sample for testing. Samples of 5 and 10 g were more likely to be positive than were 1-g samples when larval densities were less than three larvae per gram (lpg). This difference is important because ingested meat with 1 lpg is considered the threshold for clinical disease in humans. Using a 5-g sample size, all samples containing 1.3 to 2 lpg were detected, and 60 to 100% of samples with infected horse meat containing 0.1 to 0.7 lpg were detected. In this study, the double separatory funnel digestion assay was efficient and reliable for its intended use in food safety and trade. This procedure is the only digestion assay for Trichinella in horse meat that has been validated as consistent and effective at critical levels of sensitivity.

Endemic toxoplasmosis in pigs on a farm in Maryland: isolation and genetic characterization of Toxoplasma gondii.

The prevalence of Toxoplasma gondii was investigated on a poorly managed pig farm in Maryland. Serum and tissue samples from 48 of the 100 pigs on the farm were available for T. gondii evaluation. Serological testing was performed using both ELISA and the modified agglutination test (MAT). Antibodies to T. gondii were detected by ELISA in 12 of 48 animals, while antibodies were detected in 34 of 48 pigs by MAT with titers of 1:10 in 1, 1:20 in 4, 1:40 in 7, 1:80 in 3, 1:160 in 8, 1:320 in 3, 1:640 in 4, and 1:1,280 in 4. Hearts of 16 pigs with MAT titers of 1:10 or higher were bioassayed for T. gondii in cats; 11 cats shed T. gondii oocysts. Hearts of 22 pigs were autolyzed and bioassayed only in mice; T. gondii was isolated from 3 of these 22 pigs. Genetic typing of the 14 T. gondii isolates using the SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico loci revealed 4 genotypes; 10 isolates belonged to type II lineage (genotypes 1 and 2), 3 belonged to genotype 3, and 1 belonged to genotype 4. Genotype 1 and 2 have type II alleles at all genetic loci, except the former has type II allele and the latter has a type I allele at locus Apico. Both genotypes 1 and 2 are considered to belong to the clonal type II lineages. Genotype 3 and 4 are nonclonal isolates. Results document high prevalence of T. gondii in pigs on a farm in Maryland.

Trichinella murrelli in scavenging mammals from south-central Wisconsin, USA.

Tissues and serum from 59 raccoons (Procyon lotor), 42 coyotes (Canis latrans), and seven Striped Skunks (Mephitis mephitis) collected in Dane and Iowa Counties, Wisconsin, USA, between October 2005 and March 2006 were microscopically and serologically examined for the presence of Trichinella spp. Encapsulated larvae were found on compression slides prepared from tongue tissues from a few animals. Complete tissue digestion of tongues revealed that 19% of the raccoons, 26% of the coyotes, and none of the seven skunks tested were infected with Trichinella spp. Cats were subsequently experimentally infected by feeding them the raccoon tissues containing muscle larvae, and muscle larvae isolated from the collected tongues were experimentally transmitted to mice. Multiplex polymerase chain reaction analysis of the isolated muscle larvae demonstrated two distinct bands migrating at 127 base pairs (bp) and 316 bp in all samples, which together are diagnostic for Trichinella murrelli; the isolates were assigned Istituto Superiore di Sanita (ISS) codes ISS1656 through ISS1667, and ISS1708 through ISS1710 by the International Trichinella Reference Centre. These findings extend the geographic range of T. murrelli into Wisconsin, USA.

Rapid inactivation of Toxoplasma gondii bradyzoites during formulation of dry cured ready-to-eat pork sausage.

Curing processes for pork meat in the U.S. currently require individual validation of methods to demonstrate inactivation of Trichinella spiralis, a nematode parasite historically associated with pork. However, for protozoan parasites, no such strictures exist. It has been assumed, with little evidence, that curing processes required to inactivate Trichinella also inactivate Toxoplasma gondii. Currently no model of meat chemistry exists that can be correlated with inactivation of T. gondii. Given the possibility of the presence of T. gondii in pork meat, and the frequent use of pork for ready-to-eat (RTE) products not intended to be cooked, curing methods which inactivate T. gondii early in the curing process would be of great value to producers. In this study, we tested the effect of five variables - salt/brine concentration, water activity (aw), pH, temperature, and time on inactivation of T. gondii bradyzoites in tissue cysts using low and high endpoints for common curing treatments during preparation of dry cured pork sausage. Survival of T. gondii bradyzoites at each stage of preparation was assessed using a mouse bioassay. Results indicated that encysted T. gondii bradyzoites do not survive the early stages of the dry curing process within the endpoint parameters tested here, even at levels of NaCl that are lower than typically used for dry curing (1.3%). Exposure of T. gondii encysted bradyzoites to curing components in the formulated batter resulted in rapid inactivation of bradyzoites. These data suggest that the use of dry curing components may be effective for controlling T. gondii potentially transmitted through RTE meats, rendering them safe from risk with respect to T. gondii transmission to human consumers.

Skeletal muscle protein tyrosine phosphatase activity and tyrosine phosphatase 1B protein content are associated with insulin action and resistance.

Particulate and cytosolic protein tyrosine phosphatase (PTPase) activity was measured in skeletal muscle from 15 insulin-sensitive subjects and 5 insulin-resistant nondiabetic subjects, as well as 18 subjects with non-insulin-dependent diabetes mellitus (NIDDM). Approximately 90% of total PTPase activity resided in the particulate fraction. In comparison with lean nondiabetic subjects, particulate PTPase activity was reduced 21% (P < 0.05) and 22% (P < 0.005) in obese nondiabetic and NIDDM subjects, respectively. PTPase1B protein levels were likewise decreased by 38% in NIDDM subjects (P < 0.05). During hyperinsulinemic glucose clamps, glucose disposal rates (GDR) increased approximately sixfold in lean control and twofold in NIDDM subjects, while particulate PTPase activity did not change. However, a strong positive correlation (r = 0.64, P < 0.001) existed between particulate PTPase activity and insulin-stimulated GDR. In five obese NIDDM subjects, weight loss of approximately 10% body wt resulted in a significant and corresponding increase in both particulate PTPase activity and insulin-stimulated GDR. These findings indicate that skeletal muscle particulate PTPase activity and PTPase1B protein content reflect in vivo insulin sensitivity and are reduced in insulin resistant states. We conclude that skeletal muscle PTPase activity is involved in the chronic, but not acute regulation of insulin action, and that the decreased enzyme activity may have a role in the insulin resistance of obesity and NIDDM.

Two related regulatory sequences are required for maximal induction of Saccharomyces cerevisiae his3 transcription.

In Saccharomyces cerevisiae, the coordinate induction of his3 and other amino acid biosynthesis genes is mediated by the binding of GCN4 activator protein to specific promoter sequences. The his3 regulatory region contains the sequence TGACTC, which with some variation is repeated six times upstream of the mRNA initiation site. The requirements for maximal his3 induction were examined with a series of sequential 5' deletion mutations as well as a set of small internal deletions. Deletions encroaching as far downstream as position -142 behave indistinguishably from the wild-type gene, thus indicating that the two proximal copies of the regulatory sequence are sufficient for maximal induction. Deletions with breakpoints between -137 and -99 confer inducibility, but not to the normal wild-type level. A deletion ending immediately upstream of the proximal TGACTC sequence (position -99) shows some constitutive expression that is independent of the gcn4 gene product. Deletions extending to -94 or beyond do not produce detectable levels of his3 mRNA. Small internal deletions that only remove the proximal regulatory sequence and a 1-base-pair deletion of the thymine residue at -99 abolish induction, but do not affect the basal level of transcription. These results indicate that the proximal copy between -99 and -94 is absolutely required for his3 induction, whereas the copy between -142 and -137 is required only for the maximal level of induction and is inactive by itself. From these and other observations, we suggest the possibility that these related regulatory sequences may be targets for two distinct proteins.

Viability and infectivity of Trichinella spiralis muscle larvae in frozen horse tissue.

Many aspects of the biology and epidemiology of Trichinella infection in the horse are poorly understood, including survival of Trichinella spp in horse muscle. In this study, we have assessed the freeze tolerance of T. spiralis in horse meat stored at 5, -5, and -18 degrees C for 1 day to 24 weeks. Results demonstrate a steady reduction in the number of live ML recovered from the cold stored meat samples. On Day 1, recovery of live larvae had been reduced by 18.6%, 50.1%, and 37.2%, and by 4 weeks, recovery of larvae had been reduced by 65.4%, 66.5%, and 96.2% in samples stored at 5, -5, and -18 degrees C, respectively. Infectivity results (measured as reproductive capacity index (RCI)) from mice inoculated with larvae recovered from non-frozen meat samples at day 0 was 23.5. Following storage at -18 degrees C for one and two days, the RCIs were 2.09 and 0.99, respectively. Small numbers of infective larvae were still present in meat samples stored at -18 degrees C for 4 weeks. The RCI of ML recovered from meat samples stored at -5 degrees C was 14.99 and 6.36 at 2 weeks and 4 weeks respectively; the RCI of samples stored at 5 degrees C was 23.1 at 8 weeks, and fell rapidly thereafter (12 week RCI 1.33; 0 at 24 weeks). These data demonstrate that infective T. spiralis, a non-freeze tolerant species, can survive for at least 4 weeks in horse tissue frozen at -5 or -18 degrees C, and that the numbers of infective larvae decrease substantially by day 2 at -18 degrees C and by week 4 at -5 degrees C.

Larval viability and serological response in horses with long-term Trichinella spiralis infection.

The horse is considered an aberrant host for the nematode parasite Trichinella spiralis, and many aspects of the biology and epidemiology of Trichinella infection in the horse are poorly understood. It has been reported that experimentally-infected horses produce a transient serological response to infection and that muscle larvae are cleared more rapidly than in parasite-adapted hosts such as the pig and humans. However, limited numbers of animals have been studied, and both the longevity of larvae in horse musculature and the immune response to Trichinella larvae remain unclear. In this study, we infected 35 horses with 1000, 5000, or 10,000 T. spiralis muscle larvae and followed the course of infection for 1 year, assessing larval burdens in selected muscles, the condition and infectivity of recovered larvae, and the serological response of infected horses. The results demonstrated that T. spiralis establishes infection in horses in a dose dependent manner. Anti-Trichinella IgG antibodies peaked between weeks 6-10 post-inoculation. Viable, infective larvae persisted in horse musculature for the duration of the study (12 months), and exhibited no apparent reduction in muscle burdens over this period. Encapsulated larvae showed no obvious signs of degeneration in histological sections. Larval capsules were surrounded by infiltrates consisting of mature plasma cells and eosinophils. Macrophages were notably absent. Given the lack of a detectable serological response by 26 weeks p.i. and the persistence of infective muscle larvae for at least 1 year, parasite recovery methods are currently the only suitable detection assays for both meat inspection and epidemiological studies of Trichinella infection in the horse.

Fecal and serological survey of Neospora caninum in farm dogs in Costa Rica.

To detect oocysts of Neospora caninum in dog feces and to determine the excretion pattern in dogs from specialized dairy farms in Costa Rica, a total of 265 fecal samples from 34 dogs were collected at intervals from February to August 2005. Fecal samples were examined for N. caninum-like oocysts microscopically, by DNA detection using the polymerase chain reaction (PCR), and by bioassay. N. caninum DNA was detected by PCR in four fecal samples, twice from one dog, but oocysts were not detected microscopically in these dogs. Sera of 31 of 34 dogs were tested for antibodies to N. caninum by a competitive-inhibition ELISA (VMRD). Fifteen (48.4%) of 31 dogs had antibodies to N. caninum by ELISA. Seroconversion was not found in 28 dogs that were bled twice, 4 months apart (March and July 2005). Only one dog tested positive to N. caninum by both ELISA and PCR. This is the first report of finding N. caninum DNA in feces of naturally infected dogs in Costa Rican dairy farms.

Neosporosis in Beagle dogs: clinical signs, diagnosis, treatment, isolation and genetic characterization of Neospora caninum.

Clinical neosporosis was diagnosed in a litter of five pups born to a Beagle bitch from Virginia, USA. Four of the pups developed limb weakness starting at 4 weeks of age. The dogs were suspected to have neosporosis based on clinical signs and empirically treated with Clindamycin (75 mg, oral, twice daily, total 150 mg) starting at 9 weeks of age and the dosage was doubled at 13 weeks of age. Antibodies to Neospora caninum were detected in sera of the dam and pups when first tested serologically at the age of 4 months. The owner donated the pup with the worst clinical signs and the dam for research; both dogs were euthanized. Viable N. caninum was isolated in gamma interferon gene knock out (KO) mice and in cell culture from the pup killed at 137 days of age. Tissue cysts, but no tachyzoites, were found in histological sections of brain and muscles. The isolate was also identified as N. caninum by PCR and sequence analysis and designated NC-9. N. caninum was neither isolated by bioassay in KO mice nor found in histological sections of tissues of the bitch. Clinical signs in the remaining three pups improved considerably after a 6-month treatment with Clindamycin; N. caninum antibody titers were still persistent in these pups at 23 months of age. Results indicate that medication with Clindamycin can improve clinical condition but not eliminate N. caninum infection.

Curing conditions to inactivate Trichinella spiralis muscle larvae in ready-to-eat pork sausage.

Curing processes are one method by which pork products, which are considered ready to eat (RTE) and have not been otherwise tested or treated, can be rendered safe from risk for exposure to Trichinella muscle larvae (ML). Curing processes in the U.S. currently require individual validation of methods to demonstrate inactivation of Trichinella. This is a major undertaking for each process; currently no model of meat chemistry exists that can be correlated with inactivation of Trichinella. Given the potential for new RTE products (e.g., lower salt), the availability of a wider range of tested methods for inactivation of Trichinella in pork would be of substantial value to the industry. In this study, five variables were tested - salt/brine concentration, water activity (aw), pH, temperature, and time, using low and high endpoints for common curing treatments for dry cured pork sausage. The data demonstrated that NaCl concentrations above 1.3%, in combination with fermentation to pH 5.2 or below, resulted in inactivation of > 96% of Trichinella ML in stuffed sausages within 24-28 h. All ML were inactivated by 7-10 days post-stuffing. These curing processes reliably predict inactivation of Trichinella spiralis, and can be used within the defined upper and lower endpoint parameters to reduce or eliminate the need for individual product validation.

Effects of time and temperature on the viability of Toxoplasma gondii tissue cysts in enhanced pork loin.

Enhanced or pumped pork products represent a significant proportion (40 to 50%) of the commercially available pork cuts available to consumers at the retail level. In a previous study, pork loins containing viable Toxoplasma gondii tissue cysts were pumped with solutions containing 2% sodium chloride or 1.4% or higher potassium or sodium lactate and stored at 4 degrees C for 7 days. This treatment prevented transmission of T. gondii to cats. In the present study, enhanced pork loins were stored for 0, 8, 16, 24, 32, or 40 h at 4 degrees C and then fed to T. gondii-seronegative cats to determine how quickly the loss of tissue cyst viability occurred. In a second experiment, pork loins collected from pigs experimentally infected with T. gondii were stored at temperatures found in retail meat cases and then fed to T. gondii-seronegative cats to determine the effect of typical meat case storage temperatures on tissue cyst viability. In both experiments, cat feces were examined for 14 days after the infected meat meal to assess oocyst shedding. The results indicate that solutions containing 2% sodium chloride or 1.4% potassium or sodium lactate are effective within 8 h of injection for killing T. gondii tissue cysts in pork loins and that storage at meat case temperatures at or below 0 degrees C (32 degrees F) for 7 days also killed T. gondii tissue cysts in pork loins.

A Trichinella murrelli infection in a domestic dog in the United States.

Trichinella murrelli infection was diagnosed in a naturally infected Beagle bitch from VA, USA, where encapsulated larvae were found in histological sections of several skeletal muscles. A laboratory reared dog fed infected muscles resulted in viable muscle larvae that were subsequently infective to Swiss-Webster mice. Multiplex PCR using larvae from the experimentally infected dog demonstrated two distinct bands migrating at 127 bp and 316 bp which together are diagnostic for T. murrelli; the isolate was assigned the ISS code: ISS1608 by the International Trichinella Reference Centre. This is the first report of T. murrelli infection in a companion animal.