Nematode control in suckler beef cattle over their first two grazing seasons using a targeted selective treatment approach

peer-reviewedBackground With concerns over the development of anthelmintic resistance in cattle nematode populations, we must re-examine our approach to nematode control in cattle. Targeted selective treatments (TST), whereby individual animals are treated instead of entire groups, are being investigated as an alternative. The study objective was to determine if anthelmintic usage could be reduced using a TST-based approach to nematode control in spring-born suckler beef cattle over their first and second grazing seasons (SGS) without affecting performance. In the first grazing season (FGS), 99 calves with an initial mean (s.d.) calf age and live weight on day 0 (June 28th 2012) of 107 (23.1) days and 160 (32.5) kg, respectively, were used. The study commenced on day 0 when calves were randomised and allocated to one of two treatments; 1), standard treatment (control) and 2), TST. Control calves were treated subcutaneously with ivermectin on days 0, 41 and 82 in the FGS. All calves were treated with ivermectin on day 124 and housed on day 133. In the SGS, only heifer calves from the FGS were used and control heifers were treated with ivermectin on day 393. Animals were weighed, blood and faecal sampled every three weeks. The TST animals were treated with ivermectin if thresholds based on a combination of plasma pepsinogen concentrations, faecal egg count and/or the presence of Dictyocaulus viviparus larvae in faeces (FGS only) were reached. Results No TST calves reached the treatment threshold criteria in the FGS. The FGS average daily live weight gain (ADG ± s.e.m.) for control and TST group calves was 0.89 ± 0.02 kg and 0.94 ± 0.02 kg day−1, respectively (P = 0.17). In the SGS, all heifers were treated with ivermectin on day 431 due to clinical signs of respiratory disease. The ADG for control and TST heifers from turnout on day 321 to day 431 was 0.90 ± 0.04 and 0.80 ± 0.04 kg day−1, respectively (P = 0.03). Conclusions Spring-born FGS suckler beef calves require minimal anthelmintic treatment to maintain performance. In contrast, clinical parasitic disease may develop in the SGS unless appropriate anthelmintic treatment is provided

EPIDEMIOLOGY OF TUBERCULOSIS IN INTERNATIONALLY DISPLACED CHILDREN RESETTLING IN HARRIS COUNTY

Background More than 300,000 refugees arrived in the United States (U.S.) from 2010-2015, and Texas accepts the 2nd highest number of refugees. Texas also accepts large numbers of asylees, parolees, and special immigrant visa holders. Additionally, a large proportion of trafficked persons in the U.S. live in or pass through Texas. Foreign-born children are disproportionately affected by tuberculosis (TB) and account for two-thirds of U.S. childhood TB cases. Children are at greater risk for progression from TB infection to disease and experience greater morbidity and mortality from TB disease. This makes screening for and treatment of TB infection in children from high-prevalence areas an important public health intervention. Since 2007, children 2-14 years old emigrating from high-prevalence countries (TB incidence \u3e20 cases /100,000 persons) have been tested for TB infection. Children ≥15 years old are additionally screened with a chest radiograph. The Centers for Disease Control and Prevention (CDC) recommends treatment of children with TB infection, as treatment reduces the risk of life threatening disease and prevents future transmission. There are few studies describing the epidemiology of TB in internationally displaced children relocating to the U.S.; there have been no studies centered on Texas. We describe the secular trends and comparative epidemiology of positive TSTs and IGRAs in children of different immigration statuses cared for through the Houston-area public health program. Methods This was a retrospective cross-sectional study of children \u3c18 years-old evaluated by the Harris County Public Health Refugee Health Screening Program between January 1st, 2010 and December 31st, 2015 with the following immigration statuses: refugee, asylee, parolee, special immigrant visa holder, or victim of human trafficking. We analyzed factors associated with TB test positivity, infection and disease for children with these immigration statuses. Data are from the U.S. Committee for Refugees and Immigrants (USCRI), the Harris County Public Health Refugee Health Screening Program, and the Texas Children\u27s Hospital TB clinic. Chi-square test or Fisher’s exact test were used for dichotomous variables, one-way ANOVAs for univariate analyses, and Wilcoxon rank sum or Kruskal-Wallis for continuous variables. Multivariate logistic regression was performed to further analyze factors associated with TB test positivity. To assess secular trends in usage and positivity, monthly totals were analyzed using linear regression and the Wilcoxon Sign Rank test. A p-value \u3c0.05 was considered significant. Children \u3c 5 years were typically tested using tuberculin skin test (TSTs) and older children typically using interferon-gamma release assays (IGRAs). The primary outcome was a positive test of TB infection (TST and/or IGRA). Children who were TST+/IGRA- with no known contacts, a normal chest radiograph and no signs or symptoms consistent with TB disease were typically considered uninfected. However, there were some children who met these criteria who were considered to have TB infection and were treated as such –this typically occurred earlier in the study period, and was most commonly due to young age (\u3c 2 years old) or some variability in provider practice. Results The program evaluated 5,990 children, of whom 5870 (98%) were tested, predominantly (64%) with an IGRA alone. During the study period, IGRA use increased (p\u3c0.001), though percentages of positive test results (IGRA or TST) did not decline significantly (p=0.10). Overall, 364 (6.2%) children had at least one positive test of infection: 143/1,842 (7.8%) tested with TST alone, 129/3,730 (63.6%) tested with IGRA alone, and 92/298 (30.9%) had at least one positive test result for those tested with both TST and IGRA. Among the 364 children with any positive test of infection, 4 (1.1%) were diagnosed with TB disease, 325 (89.3%) were diagnosed with TB infection, and 35 (9.6%) were considered uninfected. Three factors were significantly associated with a positive TST or IGRA result: region of origin, younger age group, and HIV infection. All children were more likely to have a positive TST compared to IGRA (OR 2.92, 95% CI: 2.37-3.59). Discordant test results were common (20%) and most often were TST+/IGRA- (95.0%). 35/57 (61.4%) of children who were TST+/IGRA- were considered uninfected and did not receive therapy for TB infection; none developed TB disease. The 22/57 (38.6%) TST+/IGRA- children who were treated for TB infection, were treated as such typically due to young age (\u3c 2 years old) or variability in provider practice. Conclusions Positive TST results were twice as common as positive IGRA results and discordant TST/IGRA results were common. Positive TST results in BCG-immunized children frequently represent cross-reactivity and false positivity. Use of IGRAs as opposed to TSTs in BCG-immunized children would reduce false positive tests and allow for TB infection therapy to be targeted to those who would most benefit. These findings support 2018 changes in U.S. immigration guidelines that mandate IGRA use for recently immigrated children above 2 years of age

QuantiFERON®-TB gold in-tube performance for diagnosing active tuberculosis in children and adults in a high burden setting.

To determine whether QuantiFERON®-TB Gold In-Tube (QFT) can contribute to the diagnosis of active tuberculosis (TB) in children in a high-burden setting and to assess the performance of QFT and tuberculin skin test (TST) in a prospective cohort of TB suspect children compared to adults with confirmed TB in Tanzania. Sensitivity and specificity of QFT and TST for diagnosing active TB as well as indeterminate QFT rates and IFN-γ levels were assessed in 211 TB suspect children in a Tanzanian district hospital and contrasted in 90 adults with confirmed pulmonary TB. Sensitivity of QFT and TST in children with confirmed TB was 19% (5/27) and 6% (2/31) respectively. In adults sensitivity of QFT and TST was 84% (73/87) and 85% (63/74). The QFT indeterminate rate in children and adults was 27% and 3%. Median levels of IFN-γ were lower in children than adults, particularly children <2 years and HIV infected. An indeterminate result was associated with age <2 years but not malnutrition or HIV status. Overall childhood mortality was 19% and associated with an indeterminate QFT result at baseline. QFT and TST showed poor performance and a surprisingly low sensitivity in children. In contrast the performance in Tanzanian adults was good and comparable to performance in high-income countries. Indeterminate results in children were associated with young age and increased mortality. Neither test can be recommended for diagnosing active TB in children with immature or impaired immunity in a high-burden setting

Asymptotically Schroedinger Space-Times: TsT Transformations and Thermodynamics

We study the complete class of 5-dimensional asymptotically Schroedinger space-times that can be obtained as the TsT transform of a 5-dimensional asymptotically AdS space-time. Based on this we identify a conformal class of Schroedinger boundaries. We use a Fefferman-Graham type expansion to study the on-shell action for this class of asymptotically Schroedinger space-times and we show that its value is TsT invariant. In the second part we focus on black hole space-times and prove that black hole thermodynamics is also TsT invariant. We use this knowledge to argue that thermal global Schroedinger space-time at finite chemical potential undergoes a Hawking-Page type phase transition.Comment: References adde

Thermal spin-transfer in Fe-MgO-Fe tunnel junctions

We compute thermal spin transfer torques (TST) in Fe-MgO-Fe tunnel junctions using a first principles wave function-matching method. At room temperature, the TST in a junction with 3 MgO monolayers amounts to 10^-7J/m^2/K, which is estimated to cause magnetization reversal for temperature differences over the barrier of the order of 10 K. The large TST can be explained by multiple scattering between interface states through ultrathin barriers. The angular dependence of the TST can be very skewed, possibly leading to thermally induced high-frequency generation.Comment: 5 pages, 5 figure

Screening for Tuberculosis in Health Care Workers. Experience in an Italian Teaching Hospital

Health care workers (HCW) are particularly at risk of acquiring tuberculosis (TB), even in countries with low TB incidence. Therefore, TB screening in HCW is a useful prevention strategy in countries with both low and high TB incidence. Tuberculin skin test (TST) is widely used although it suffers of low specificity; on the contrary, the in vitro enzyme immunoassay tests (IGRA) show superior specificity and sensitivity but are more expensive. The present study reports the results of a three-year TB surveillance among HCW in a large teaching hospital in Rome, using TST (by standard Mantoux technique) and IGRA (by QuantiFERON-TB) as first- and second-level screening tests, respectively. Out of 2290 HCW enrolled, 141 (6.1%) had a positive TST; among them, 99 (70.2%) underwent the IGRA and 16 tested positive (16.1%). The frequency of HCW tested positive for TB seems not far from other experiences in low incidence countries. Our results confirm the higher specificity of IGRA, but, due to its higher cost, TST can be considered a good first level screening test, whose positive results should be further confirmed by IGRA before the patients undergo X-ray diagnosis and/or chemotherapy

Nursing and community rates of Mycobacterium tuberculosis infection among students in Harare, Zimbabwe.

BACKGROUND: African hospitals have experienced major increases in admissions for tuberculosis, but they are ill-equipped to prevent institutional transmission. We compared institutional rates and community rates of tuberculin skin test (TST) conversion in Harare, Zimbabwe. METHODS: We conducted a cohort study of TST conversion 6, 12, and 18 months into training among 159 nursing and 195 polytechnic school students in Harare. Students had negative TST results (induration diameter, or =10 mm) per 100 person-years (95% confidence interval [CI], 14.2-26.2 conversions per 100 person-years), and polytechnic school students experienced 6.0 (95% CI, 3.5-10.4) conversions per 100 person-years. The rate of difference was 13.2 conversions (95% CI, 6.5-20.0) per 100 person-years. With a more stringent definition of conversion (increase in the induration diameter of > or =10 mm to at least 15 mm), which is likely to increase specificity but decrease sensitivity, conversion rates were 12.5 and 2.8 conversions per 100 person-years in nursing and polytechnic school students, respectively (rate difference, 9.7 conversions per 100 person-years; 95% CI, 4.5-14.8 conversions per 100 person-years). Nursing students reportedly nursed 20,868 inpatients with tuberculosis during 315 person-years of training. CONCLUSIONS: Both groups had high TST conversion rates, but the extremely high rates among nursing students imply high occupational exposure to Mycobacterium tuberculosis. Intense exposure to inpatients with tuberculosis was reported during training. Better prevention, surveillance, and management of institutional M. tuberculosis transmission need to be supported as part of the international response to the severe human immunodeficiency virus infection epidemic and health care worker crisis in Africa