Rate Of Positive Test Results Research Articles

Pandemic (H1N1) 2009 Virus Circulating in Pigs, Guangxi, China

To the Editor: A novel swine-originated influenza A virus known as pandemic (H1N1) 2009 was first isolated from humans in Mexico in April 2009 (1), and a worldwide pandemic followed, which affected >214 countries and resulted in >18,000 deaths (2). In August 2010, the World Health Organization stated that the pandemic caused by this virus had ended. As this virus emerged, animals, including swine, turkeys, ferrets, cats, and cheetahs, were found to have been infected (3). In addition, transmission from humans to pigs in porcine herds has been reported (4). Swine influenza A virus (SIV) belongs to the family Orthomyxoviridae and is a causative agent of respiratory disease in pigs (5). Currently, 3 subtypes of influenza viruses are circulating in the swine population globally: H1N1, H3N2, and H1N2 (6,7). Although pigs can be simultaneously infected with avian influenza viruses and human influenza viruses, the viruses can exchange genes and produce new variants, which suggests that pigs have become mixing vessels for influenza viruses (8). Pandemic (H1N1) 2009, caused by a virus usually circulating in pigs in Europe and Asia, is a triple hybrid that contains swine, human, and avian virus gene segments, which further emphasizes that SIVs pose a serious threat to public health. We describe an outbreak of pandemic (H1N1) 2009 virus, which was isolated from a pig farm in Guangxi Province, People’s Republic of China, and report the consequences of subsequent epidemiologic studies. In January 2011, an outbreak of severe respiratory problems occurred in pigs on a pig farm. Nine hundred growing and fattening pigs exhibited clinical signs of influenza, including fever, cough, runny nose, loss of appetite, lethargy, edema, watery eyes, conjunctivitis, diarrhea, and vomiting. The incidence rate was ≈80%, and the death rate was 22%. The outbreak lasted ≈2 weeks. However, no outbreak of respiratory disease occurred in other pig farms in the same area simultaneously, and no evidence of human-to-pig transmission was found. We collected lung samples from 3 dead pigs with underlying illness for reverse transcription PCR and virus isolation in 10-day-old specific pathogen–free embryonated chicken eggs. Viral RNA was extracted from the tissue suspension and allantoic fluids. Virus isolation was assessed by hemagglutination inhibition (HI) assay and neuraminidase inhibition assay by using a panel of reference serum samples (National Reference Laboratory for Avian Influenza, Harbin Veterinary Research Institute, Harbin City, China). Later, 3 viruses were isolated. All of them had hemagglutination (HA) activity, and the HA titers ranged from 128–256. The HA-positive isolates were further identified as subtype H1N1. Subsequently, nucleotide sequences of the 8 viral genes were amplified and sequenced (GenBank accession nos. {type:entrez-nucleotide-range,attrs:{text:JN222372-JN222379,start_term:JN222372,end_term:JN222379,start_term_id:339782164,end_term_id:339782180}}JN222372-JN222379). This analysis showed high identities to a pandemic strains A/California/04/2009 (H1N1), hemagglutinin (99.2%), neuraminidase (99.1%), matrix (99.3%), nucleoprotein (99.5%), nonstructural protein (98.5%), polymerase acidic protein (98.5%), polymerase basic protein 1 (99.7%), and polymerase basic protein 2 (99.6%) genes. Bacteria were cultured from spleen, liver, and heart-blood samples from 5 pigs. Four pigs were infected with porcine streptococci, and 1 pig with mild symptoms was negative for the bacterium. We sought to gain more insight into the epidemiology of pandemic (H1N1) 2009 virus in Guangxi Province and collected 600 bronchial swab samples and 200 blood serum samples when pigs were slaughtered every month from February through June 2011. The samples were used to isolate virus in 10-day-old specific pathogen–free embryonated chicken eggs, and then the virus isolates were subjected to sequencing of a partial genome of the HA gene. Overall, we obtained 10 strains of subtype H1N1 influenza virus, including 5 strains of classic swine H1N1, 3 strains of Eurasian avianlike H1N1, and 2 strains of pandemic (H1N1) 2009 virus, which were derived from 3,000 bronchial swab samples. In addition, a serologic survey was implemented by using HI testing with pandemic (H1N1) 2009 virus and SIV (H1N1) antigens. Serologic studies showed that 251 of the 1,000 samples tested had positive HI titers for pandemic (H1N1) 2009 virus, and 248 of these samples had positive HI titers for SIV (H1N1). Notably, cross-reactivity of pandemic (H1N1) 2009 virus between H1 subtype viruses has been reported recently in pigs (9). However, the higher rate of positive test results indicated that swine serum samples contained antibodies against pandemic (H1N1) 2009 virus. Our findings strengthened previous data by showing that growing and fattening pigs are susceptible to infection of pandemic (H1N1) 2009 virus (4). Analysis of the complete genome sequence of the subtype H1N1 isolates suggests that no gene reassortment occurred. The results of serologic studies demonstrated that uninfected pig farms are also susceptible to pandemic (H1N1) 2009 virus infection. Our results suggest that the pandemic virus is currently circulating in swine populations and posing a challenge to pigs in southern China. Increasing serologic surveillance of pigs for prevention and better control of pandemic influenza is urgently needed in China.

Hereditary Breast Ovarian Cancer Syndromes in the Maritimes

ObjectivesThe purpose of this study was to characterize the population referred to the Maritime Medical Genetics Service (MMGS) because of increased risk of breast and/or ovarian cancer, and to evaluate the MMGS referral criteria for this population. MethodsWe reviewed a retrospective cohort of patients at increased risk of breast and/or ovarian cancer (n = 574) with appointments between January 2001 and May 2007 at the MMGS. Data analysis was performed using descriptive statistics in Filemaker Pro 8.5v1 and Microsoft Excel. ResultsAmong 574 patients, 253 (44%) had test results available at the time of data collection, and 65 (25.7%) had BRCA mutations (44 BRCA1 and 21 BRCA2). Positive test results for each referral criterion ranged from 0% to 100%. ConclusionUse of referral criteria at the MMGS yielded higher rates of positive test results than previously thought. It may be beneficial to expand testing criteria to ensure that everyone who may carry a mutation is offered testing.

Cardiological diagnostic work‐up in stroke patients – a comprehensive study of test results and therapeutic implications

In some Western countries, many stroke patients undergo routine tests including ECG, echocardiography, carotid ultrasound and Holter monitoring, even though they have been shown to express limited value in unselected patients. Comprehensive data on yield of tests, especially on consequences taken from positive test results, are scanty. Consecutive stroke patients with evidence of ischaemic lesions by imaging techniques were included. Aetiology was determined using TOAST-classifications. Rates of positive test results and their impact on drug therapy, especially anticoagulation were evaluated. Two hundred and forty-one consecutive patients, age 69 +/- 13 years were included. Positive test results were documented in 19% with 12-lead ECG, 24% with carotid ultrasound, 24% with echocardiography and never with Holter monitoring. Overall, in 41% positive test results were present. Apart from echocardiography (37%), a change of therapy resulted in 51-56% of patients with a positive test result. Even though 12-lead ECG, carotid ultrasound and echocardiography only had relatively low incidences of positive findings, their impact on management in case of positive test results was quite high. Nevertheless, future studies to select patients more appropriately are needed. In contrast, Holter monitoring had no impact and should not be used in routine evaluation of stroke patients.

Prevalence of Tuberculosis Infection Among Health-Care Workers in Hamedan, West of Iran

Objectives: The aim of this study was to ascertain the prevalence of latent TB infection and pulmonary TB, and to assess the risk factors for TB, among health care workers in Hamadan. Patients and Methods: Tuberculin skin test was performed on 245 health care workers, in two educational hospitals. The reaction was considered as if the induration diameter was ≥ 10 mm. Individuals with a positive test > than 15 mm were encouraged to seek further medical evaluation, including a chest-x-ray and a smear and sputum culture of the sputum for acid-fast bacilli, in those with radiographic changes indicating TB. Results: Out of 245 health-care workers included in this study, 92 (38%) had positive tuberculin test. There was a significant association between aging and tuberculin positivity. There was also a significant association between the length of employment and tuberculin positivity. Ward attendants had higher rates of positive test results, compared with other occupational groups. Conclusions: It was concluded that latent TB infection is common among health-care workers in the studied region. Age, occupational group and employment length were found to be strongly associated with tuberculin positivity.

Clinical significance of the soluble interleukin-2 receptor as a putative systemic nutritional index in the elderly*

Background: The clinical significance of a slight increase in serum soluble interleukin-2 receptor (sIL2R) concentration in the stable elderly was investigated. Methods: The subjects consisted of 35 residents of nursing homes with physical impairment as a sequela to cerebral infarctions, who had no inflammatory conditions, and were not receiving anodyne or immunological treatment. They were divided into two groups: 24 subjects without overt or suspected malignancy (NC) and 11 with a history of malignancy (CA). Serological screening with measurement of sIL2R concentrations was performed and numbers of lymphocytes with CD4 and CD8 markers were determined. The NC group was subdivided into control subjects (n = 15, sIL2R < = 883 U/mL) and subjects demonstrating elevated concentrations of sIL2R (n = 9, NH), as in a previous study. Results: Between the NH and control groups, differences were found in serum concentrations of albumin, blood urea nitrogen, total cholesterol concentration, Pettigrew's prognostic nutritional index (PNI) and activities of daily living score, but not in age or sex. Factor analysis in the NC group showed serum creatinine and blood urea nitrogen concentrations to be correlated positively, and serum albumin, total cholesterol concentrations, activities of daily living score, and PNI to be correlated negatively with sIL2R. Differences were found in sIL2R, albumin, total protein, total cholesterol, β-lipoprotein and PNI between the CA and control groups, but no correlations among these parameters were found in the CA group. There was no difference in the rate of positive test results for rheumatoid factor between the NC and CA, or control and NH groups. The survival rate of control subjects over 24 months was better than that of NH subjects, but not that of CA subjects. Conclusion: Our results suggest that a slight increase in the concentration of sIL2R is related to subclinical systemic deterioration, especially regarding nutrition, with a plausible connection to prognosis, in stable elderly patients without malignancy.

Postpartum metabolism and autoantibody markers in women with gestational diabetes mellitus diagnosed in early pregnancy

Objective: Our purpose was to study postpartum metabolism and autoantibody markers of type 1 diabetes mellitus in women with gestational diabetes mellitus diagnosed in early pregnancy. Study Design: Thirty women with gestational diabetes diagnosed in early pregnancy were compared with 72 women who had gestational diabetes diagnosed in late pregnancy. Glucose tolerance, parameters of carbohydrate and lipid metabolism, and antibodies to glutamic acid decarboxylase and to islet cells were measured. Results: The percentages of overt diabetes and abnormal glucose tolerance were significantly higher in the early-pregnancy group (26.7% vs 1.4%; P =.0002; and 40% vs 5.56%; P <.0001; respectively). Only 1 woman had positive test results for antibodies to the islet cells. The rate of positive test results for antibodies to glutamic acid decarboxylase was similar in both groups (13.7% vs 9.3%). Conclusions: Women with early gestational diabetes have an increased risk of postpartum diabetes mellitus, whereas those with late-onset gestational diabetes have a minimal risk. In women predisposed to type 1 diabetes, gestational diabetes develops either early or late in pregnancy. (Am J Obstet Gynecol 2001;184:965-70.)

Excited skin syndrome

Background: Excited skin syndrome (ESS) occurs when, after a battery of patch tests is applied to patients with suspect allergic contact dermatitis, an excessive number of positive patch tests is obtained that are no longer reproduced when the patient is retested. Objective: This study was performed to verify the occurence of ESS when patch tests were applied to a population with a hypothetical diagnosis of allergic contact dermatitis, to determine the rate of positive test result loss among the tested patients who developed ESS, and to try to identify factors that might initiate the ESS. Methods: From January 1985 to May 1990, patch tests were performed on 1,500 patients referred to the Allergy Sector of the Dermatology Clinic of Santa Casa de São Paulo with a hypothetical diagnosis of contact dermatitis. Thirty-four of the 1,500 patients were considered because they showed three or more positive test results during the first phase of the patch tests. These patients were submitted to the retesting of substances with positive test results in the first phase. Results and Conclusions: Analysis of the results allowed us to conclude that the frequency of ESS in the 1,500 patients tested was 2.2% and that the number of lost test results between the first and the second phase was 175, showing a loss rate of positive test results of 63.5%. Regarding the facts that might interfere with the ESS, it was shown that (1) the loss rate of positive test results varied among patients, ie, polysensitized patients showed a lower rate of test result losses than monosensitized or bisensitized patients; (2) the longer the time of evolution of the chronic eczematous dermatitis, the higher the tendency to develop ESS; (3) ESS might be initiated by positive test results of weak, medium, or high intensity; (4) when the patch tests are applied close to one another, the positive test results may induce additional responses in the area; and (5) it was not possible to show statistically that the nature of certain substances interferes with the induction of ESS.

Evaluation of four serological tests for bovine paratuberculosis.

The standard complement fixation (CF) test, a commercial agarose gel immunodiffusion (AGID) test (ImmuCell Corporation, Portland, Maine), and two commercial enzyme-linked immunosorbent assays (ELISAs; Allied Laboratories, Glenwood Springs, Colo. [Allied ELISA], and the CSL, Limited, [Parkville, Victoria, Australia] enzyme immunoassay [CSL ELISA]) were evaluated by using sera from the Repository for Paratuberculosis Specimens. The case definition of subclinical bovine paratuberculosis was isolation of Mycobacterium paratuberculosis from fecal samples or internal organs of dairy cattle without diarrhea or weight loss. Animals designated as free of the disease originated exclusively from certified paratuberculosis-free herds in Wisconsin. None of the cattle evaluated had been vaccinated for paratuberculosis. Among 177 M. paratuberculosis-infected cattle, the CF test, the AGID test, the Allied ELISA, and the CSL ELISA had test sensitivities of 38.4, 26.6, 58.8, and 43.4%, respectively, and specificities of 99.0, 100.0, 95.4, and 99.0%, respectively. Only 108 of the infected cattle were confirmed by culture or by a commercial DNA probe (IDEXX Corporation, Portland, Maine) to be shedding the organism in fecal samples at the time of serological testing. Among the 108 M. paratuberculosis fecal shedders, the CF test, the AGID test, the Allied ELISA, and the CSL ELISA were positive for 54.6, 40.7, 65.7, and 56.5% of the cows, respectively; and among the 69 cows that were nonshedders, the tests were positive for 14.5, 4.3, 47.8, and 24.6% of the cows, respectively. There was a significant difference (P < 0.05) in the rate of positive test results for all four tests between these two groups of animals. The CF test performed well when it was compared with the other serological tests if a titer of >/- 1.8 was classified as a positive test result.