Seroepidemiology of Toxoplasma in a coastal region of Haiti: multiplex bead assay detection of immunoglobulin G antibodies that recognize the SAG2A antigen.

Toxoplasma gondii is a globally distributed parasitic protozoan that infects most warm-blooded animals. We incorporated a bead coupled with recombinant SAG2A protein into our Neglected Tropical Disease (NTD) multiplex bead assay (MBA) panel and used it to determine Toxoplasma infection rates in two studies in Haiti. In a longitudinal cohort study of children aged 0-11 years, the infection rate varied with age reaching a maximum of 0·131 infections/year in children aged 3 years [95% confidence interval (CI) 0·065-0·204]. The median time to seroconversion was estimated to be 9·7 years (95% CI 7·6-∞). In a cross-sectional, community-wide survey of residents of all ages, we determined an overall seroprevalence of 28·2%. The seroprevalence age curve from the cross-sectional study also suggested that the force of infection varied with age and peaked at 0·057 infections/year (95% CI 0·033-0·080) at age 2·6 years. Integration of the Toxoplasma MBA into NTD surveys may allow for better estimates of the potential burden of congenital toxoplasmosis in underserved regions.

Probable causes of increasing brucellosis in free-ranging elk of the Greater Yellowstone Ecosystem.

While many wildlife species are threatened, some populations have recovered from previous overexploitation, and data linking these population increases with disease dynamics are limited. We present data suggesting that free-ranging elk (Cervus elaphus) are a maintenance host for Brucella abortus in new areas of the Greater Yellowstone Ecosystem (GYE). Brucellosis seroprevalence in free-ranging elk increased from 0-7% in 1991-1992 to 8-20% in 2006-2007 in four of six herd units around the GYE. These levels of brucellosis are comparable to some herd units where elk are artificially aggregated on supplemental feeding grounds. There are several possible mechanisms for this increase that we evaluated using statistical and population modeling approaches. Simulations of an age-structured population model suggest that the observed levels of seroprevalence are unlikely to be sustained by dispersal from supplemental feeding areas with relatively high seroprevalence or an older age structure. Increases in brucellosis seroprevalence and the total elk population size in areas with feeding grounds have not been statistically detectable. Meanwhile, the rate of seroprevalence increase outside the feeding grounds was related to the population size and density of each herd unit. Therefore, the data suggest that enhanced elk-to-elk transmission in free-ranging populations may be occurring due to larger winter elk aggregations. Elk populations inside and outside of the GYE that traditionally did not maintain brucellosis may now be at risk due to recent population increases. In particular, some neighboring populations of Montana elk were 5-9 times larger in 2007 than in the 1970s, with some aggregations comparable to the Wyoming feeding-ground populations. Addressing the unintended consequences of these increasing populations is complicated by limited hunter access to private lands, which places many ungulate populations out of administrative control. Agency-landowner hunting access partnerships and the protection of large predators are two management strategies that may be used to target high ungulate densities in private refuges and reduce the current and future burden of disease.

Apparent symptom overreporting in combat veterans evaluated for PTSD.

Psychometric studies have consistently shown that combat veterans evaluated for posttraumatic stress disorder (PTSD) appear to overreport psychopathology as exhibited by (a) extreme and diffuse levels of psychopathology across instruments measuring different domains of mental illness, and (b) extreme elevations on the validity scale of the MMPI-MMPI-2, in a "fake-bad" direction. The phenomenon of this ubiquitous presentational style is not well understood at present. In this review we describe and delineate the assessment problem posed by this apparent symptom overreporting, and we review the literature regarding several potential explanatory factors. Finally, we address conceptual and practical issues relevant to reaching a better understanding of the phenomenon, and ultimately the clinical syndrome of combat-related PTSD, in both research and clinical settings.

Genetic parameter estimates of live animal ultrasonic measures of retail yield indicators in yearling breeding cattle.

Ultrasonic measures of backfat thickness (BFT) and longissimus muscle area (LMA) taken on Angus bulls (n = 805) and heifers (n = 877) ranging in age from approximately 8 to 20 mo in a production setting in western Nebraska were used to estimate genetic (co)variances. Further information used in the analyses, including weaning weight (WWT), postweaning ADG, and scrotal circumference (SC), was obtained from the American Angus Association, St. Joseph, MO, for these individuals and for animals from the same herd and contemporary groups. Data were analyzed using single-trait, sire model, restricted maximum likelihood (REML) procedures to estimate starting variances for later two-trait analyses. These two-trait analyses were done to estimate variance components for WWT coupled with BFT, LMA, SC, and ADG, also using REML procedures, but with a sire-maternal grandsire model for WWT and a sire model for the other trait(s). Heritabilities for BFT, LMA, WWT direct, WWT maternal, SC, and ADG were .56, .11, .19, .24, .56, and .51, respectively. Genetic correlations between WWT direct and WWT maternal, WWT direct and LMA, WWT maternal and LMA, WWT maternal and BFT were -.57, .42, .01, and -.69, respectively. Genetic parameters from this study were used to calculate possible genetic change with a typical selection scenario, and it was shown that among WWT, BFT, and LMA, BFT could be affected the most by selection, relative to its mean.

Localization of enkephalin immunoreactivity in the spinal cord of the long-tailed ray Himantura fai.

Enkephalin-like immunoreactivity (ENK-LI) was found throughout the spinal cord of the long-tailed ray Himantura fai. The densest ENK-LI was in the superficial portion of lamina A of the dorsal horn. Lamina B and the deeper parts of lamina A contained radially oriented, labelled fibres. Laminae C, D, and E contained many longitudinally oriented fascicles which were surrounded by a reticulum of transversely oriented, labelled fibres, some of which projected into the ventral and lateral funiculi. Labelled fibres were found in the dorsal commissure and around the central canal, but the later did not cross the midline. One-third of all enkephalinergic cells were found throughout laminae A and B, while two-thirds were located in the medial half of C, D, and E. Occasionally a labelled cell was located in the lateral funiculus. The ventral horn (laminae F and G) contained many enkephalinergic fibres but no labelled nuclei. A few dorsal column axons contained ENK-LI. In the lateral funiculus there were two groups of labelled axons, a superficial, dorsolateral group, and a deeper group, occupying a crescent-shaped region. The ventral funiculus also contained many labelled axons. The central projection of the dorsal root passed through the substantia gelatinosa and divided into rostrally and caudally projecting fascicles within lamina C. The root, and these fascicles, both lacked ENK-LI. In contrast, the fascicles in laminae D and E did contain enkephalinergic fibres. The origin of the various fibre systems and the role of enkephalin in the regulation of sensory processing and motor output are discussed.

Real-time ultrasonic measurement of fat thickness and longissimus muscle area: II. Relationship between real-time ultrasound measures and carcass retail yield.

Feedlot steers (n = 180) representing 11 sire-breed groups were ultrasonically measured for fat thickness (FTU) and longissimus muscle area (LMU) at two 60-d intervals during the feeding period and four 21-d intervals corresponding to serial slaughter dates to predict carcass retail yield parameters. Two fat trim levels, 8 and 0 mm, were used to calculate percentage of trimmable fat (FAT8P and FAT0P) and retail product percentage (RPD8P and RPD0P) for each carcass. Regression techniques were used to evaluate best-fit equations that explained variation in retail product components. When FAT8P, FAT0P, RPD8P, and RPD0P were regressed on USDA yield grade (YG), R2 values ranged from 75 to 76% (P < .001). Comparatively, when live animal predictors of YG components (FTU, LMU, and final live weight) were used as the independent variables, equations predicting retail yield had R2 values of 61 to 65% (P < .01). Equations using final FTU as the independent variable explained 58 to 64% (P < .001) of the variation in FAT8P, FAT0P, RPD8P, and RPD0P. Equations with FTU, LMU, and either WT, AGE, marbling, or quality grade resulted in R2 values similar to those with only FTU, indicating the strong influence of fat on retail yields. These results indicate that ultrasonic predictors explained about 10% less variation in retail product percentage than did carcass measures.

Real-time ultrasonic measurement of fat thickness and longissimus muscle area: I. Description of age and weight effects.

Serial ultrasonic measures of fat thickness (FTU) and longissimus muscle area (LMU) were taken on 180 feedlot steers representing 11 sire-breed groups at two 60-d intervals. Cattle then were slaughtered in four groups of 45 at 21-d intervals with ultrasonic measures taken at each interval. Analyses of variance indicated weight (WT) effects (P < .001) for all FTU measures and many of the LMU measures. Age was a source of variation (P < .05) for FTU and LMU over the first five measurement dates. Sire-breed (SBD) effects (P < .001) were prevalent for all FTU estimates and early LMU predictions. Some dam line and SBD x dam line interactions were detected (P < .1) for the FTU and LMU estimates. Age effects were described quadratically (P < .001) when FTU and LMU were regressed on age (R2 = 47 and 68%, respectively). When FTU and LMU were regressed on WT, effects were described quadratically (P < .001) with R2 values of 46 and 72%, respectively. Animals then were assigned to one of four biological types (BT) based on percentage of retail product (0-mm fat trim) using discriminant cluster analysis. Within BT, ultrasonic variables were regressed on age. Quadratic effects (P < .01) were detected for both FTU and LMU. Weight also contributed to variation observed in both ultrasonically measured variables for all BT (P < .001). These data indicate that changes in fat and muscle size as affected by age and weight are detectable using serially collected ultrasound measures. Furthermore, the age and weight relationships of predicted FTA and LMA varied across the four biological types. This suggests a need for derivation of biological type-specific age and(or) weight adjustment equations for cattle evaluation purposes.

Ultrasonic prediction of carcass merit in beef cattle: evaluation of technician effects on ultrasonic estimates of carcass fat thickness and longissimus muscle area.

The objective of this study was to determine technician effects of live animal ultrasonic estimates of fat thickness (FTU) and longissimus muscle area (LMAU). Steers (n = 36) representing four breed-types (Brown Swiss, Average Zebu-cross Mexican, Corriente Mexican, and typical British crossbred) of commercial slaughter cattle were isonified to estimate accuracy and repeatability of fat thickness (FT) and longissimus muscle area (LMA) measurements by two experienced technicians. Repeated measures of FTU and LMAU were taken by technicians on two consecutive days with an Aloka 500V ultrasound unit equipped with a 3.5-MHz, 172-mm scanning width, linear-array transducer. Ultrasonic estimates of fat thickness and LMAU were taken at the 12th and 13th rib interface 48 h before slaughter; carcass fat thickness (FTC) and longissimus muscle area (LMAC) were measured 48 h postmortem. Means for FTU, FTC, LMAU, and LMAC were .91 +/- .36 cm, .82 +/- .40 cm, 70.7 +/- 9.43 cm2, and 72.4 +/- 8.9 cm2, respectively. Ultrasound and carcass measures of FT and LMA were different (P less than .01) among breed-types but were not different (P greater than .10) between technicians or for technician x breed-type interactions. Pooled simple correlation coefficients (P less than .01) were .87 and .86 between FTU and FTC and .76 and .82 between LMAU and LMAC for Technicians 1 and 2, respectively. Repeatabilities estimated by intraclass correlation methods were .91 +/- .03 and .81 +/- .06 for images repeated over 2 d and .95 +/- .02 and .83 +/- .05 for images repeated by two technicians for FT and LMA, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of ultrasonic estimates of carcass fat thickness and longissimus muscle area in beef cattle.

Yearling crossbred feedlot steers (n = 495) and heifers (n = 151) were ultrasonically measured at the 12-13th rib interface 24 h before slaughter to evaluate the accuracy of ultrasonic measurements of fat thickness (BFU) and longissimus muscle area (LMAU) for prediction of actual carcass measures. Isonification was with an Aloka 210DX ultrasound unit equipped with a 12.5-cm, 3.0-MHz, linear array transducer by two technicians. Carcass fat thickness (BFC) and longissimus muscle area (LMAC) were measured 48 h postmortem. Differences between ultrasonic and actual carcass measures were expressed in actual (BFDIFF and LMADIFF) and in absolute (magnitude of BFDIFF and magnitude of LMADIFF) terms for backfat and longissimus muscle area, respectively. When expressed as percentages of the actual carcass measures, the average absolute differences indicated error rates of 20.6% for backfat and 9.4% for longissimus muscle area. Average actual differences (BFDIFF and LMADIFF) indicated that underprediction occurred more often than overprediction for both measures. The BFU was within .25 cm of BFC 70% of the time, and LMAU was within 6.5 cm2 of LMAC 53% of the time. Ultrasound measurements BFU and LMAU more accurately predicted BFC and LMAC in thinner and more lightly muscled cattle, respectively. Simple correlation coefficients between ultrasonic and carcass measures were .75 (P less than .01) for BF and .60 (P less than .01) for LMA. Analyses of variance of absolute differences between ultrasonic and carcass measures indicated no significant differences to exist between technicians. Predictive accuracy of ultrasonic measures did not change as the level of experience of technicians increased during the study.(ABSTRACT TRUNCATED AT 250 WORDS)