Do animal exhibitors support and follow recommendations to prevent transmission of variant influenza at agricultural fairs? A survey of animal exhibitor households after a variant influenza virus outbreak in Michigan.

Influenza A viruses circulate in swine and can spread rapidly among swine when housed in close proximity, such as at agricultural fairs. Youth who have close and prolonged contact with influenza-infected swine at agricultural fairs may be at increased risk of acquiring influenza virus infection from swine. Animal and human health officials have issued written measures to minimize influenza transmission at agricultural exhibitions; however, there is little information on the knowledge, attitudes, and practice (KAP) of these measures among animal exhibitors. After an August 2016 outbreak of influenza A(H3N2) variant ("H3N2v") virus infections (i.e., humans infected with swine influenza viruses) in Michigan, we surveyed households of animal exhibitors at eight fairs (including one with known H3N2v infections) to assess their KAP related to variant virus infections and their support for prevention measures. Among 170 households interviewed, most (90%, 151/167) perceived their risk of acquiring influenza from swine to be low or very low. Animal exhibitor households reported high levels of behaviours that put them at increased risk of variant influenza virus infections, including eating or drinking in swine barns (43%, 66/154) and hugging, kissing or snuggling with swine at agricultural fairs (31%, 48/157). Among several recommendations, including limiting the duration of swine exhibits and restricting eating and drinking in the animal barns, the only recommendation supported by a majority of households was the presence of prominent hand-washing stations with a person to monitor hand-washing behaviour (76%, 129/170). This is a unique study of KAP among animal exhibitors and highlights that animal exhibitor households engage in behaviours that could increase their risk of variant virus infections and have low support for currently recommended measures to minimize infection transmission. Further efforts are needed to understand the lack of support for recommended measures and to encourage healthy behaviours at fairs.

Outbreak of type A foodborne botulism at a boarding school, Uganda, 2008.

Botulism has rarely been reported in Africa. In October 2008, botulism was reported in three Ugandan boarding-school students. All were hospitalized and one died. A cohort study was performed to assess food exposures among students, and clinical specimens and available food samples were tested for botulinum toxin. Three case-patients were identified; a homemade, oil-based condiment was eaten by all three. In the cohort study, no foods were significantly associated with illness. Botulinum toxin type A was confirmed in clinical samples. This is the first confirmed outbreak of foodborne botulism in Uganda. A homemade, oil-based condiment was the probable source. Consumption of homemade oil-based condiments is widespread in Ugandan schools, putting children at risk. Clinicians and public health authorities in Uganda should consider botulism when clusters of acute flaccid paralysis are seen. Additionally, schools should be warned of the hazard of homemade oil-based condiments, and take steps to prevent their use.

Impact of medical and behavioural factors on influenza-like illness, healthcare-seeking, and antiviral treatment during the 2009 H1N1 pandemic: USA, 2009-2010.

We analysed a cross-sectional telephone survey of U.S. adults to assess the impact of selected characteristics on healthcare-seeking behaviours and treatment practices of people with influenza-like illness (ILI) from September 2009 to March 2010. Of 216,431 respondents, 8.1% reported ILI. After adjusting for selected characteristics, respondents aged 18-64 years with the following factors were more likely to report ILI: a diagnosis of asthma [adjusted odds ratio (aOR) 1.88, 95% CI 1.67-2.13] or heart disease (aOR 1.41, 95% CI 1.17-1.70), being disabled (aOR 1.75, 95% CI 1.57-1.96), and reporting financial barriers to healthcare access (aOR 1.63, 95% CI 1.45-1.82). Similar associations were seen in respondents aged ≥ 65 years. Forty percent of respondents with ILI sought healthcare, and 14% who sought healthcare reported receiving influenza antiviral treatment. Treatment was not more frequent in patients with high-risk conditions, except those aged 18-64 years with heart disease (aOR 1.90, 95% CI 1.03-3.51). Of patients at high risk for influenza complications, self-reported ILI was greater but receipt of antiviral treatment was not, despite guidelines recommending their use in this population.

Multistate outbreak of Listeria monocytogenes associated with Mexican-style cheese made from pasteurized milk among pregnant, Hispanic women.

Listeriosis is a severe infection caused by Listeria monocytogenes. Since 2004, the Centers for Disease Control and Prevention has requested that listeriosis patients be interviewed using a standardized Listeria Initiative (LI) questionnaire. In January 2009, states and the Centers for Disease Control and Prevention began investigating a multistate outbreak of listeriosis among pregnant, Hispanic women. We defined a case as an illness occurring between October 2008 and March 2009 with an L. monocytogenes isolate indistinguishable from the outbreak strain by pulsed-field gel electrophoresis. We conducted a multistate case-control study using controls that were selected from L. monocytogenes illnesses in non-outbreak-related pregnant, Hispanic women that were reported to the LI during 2004 to 2008. Eight cases in five states were identified. Seven of these were pregnant, Hispanic females aged 21 to 43 years, and one was a 3-year-old Hispanic girl, who was excluded from the study. Seven (100%) cases but only 26 (60%) of 43 controls had consumed Mexican-style cheese in the month before illness (odds ratio, 5.89; 95% confidence interval, 1.07 to ∞; P = 0.04). Cultures of asadero cheese made from pasteurized milk collected at a manufacturing facility during routine sampling by the Michigan Department of Agriculture on 23 February 2009 yielded the outbreak strain, leading to a recall of cheeses produced in the plant. Recalled product was traced to stores where at least three of the women had purchased cheese. This investigation highlights the usefulness of routine product sampling for identifying contaminated foods, of pulsed-field gel electrophoresis analysis to detect multistate outbreaks, and of the LI for providing timely exposure information for case-control analyses. Recalls of contaminated cheeses likely prevented additional illnesses.

Multistate outbreak of Escherichia coli O157:H7 infections associated with a national fast-food chain, 2006: a study incorporating epidemiological and food source traceback results.

A multistate outbreak of Escherichia coli O157:H7 infections occurred in the USA in November-December 2006 in patrons of restaurant chain A. We identified 77 cases with chain A exposure in four states - Delaware, New Jersey, New York, and Pennsylvania. Fifty-one (66%) patients were hospitalized, and seven (9%) developed haemolytic uraemic syndrome; none died. In a matched analysis controlling for age in 31 cases and 55 controls, illness was associated with consumption of shredded iceberg lettuce [matched odds ratio (mOR) 8·0, 95% confidence interval (CI) 1·1-348·1] and shredded cheddar cheese (mOR 6·2, CI 1·7-33·7). Lettuce, an uncooked ingredient, was more commonly consumed (97% of patients) than cheddar cheese (84%) and a single source supplied all affected restaurants. A single source of cheese could not explain the regional distribution of outbreak cases. The outbreak highlights challenges in conducting rapid multistate investigations and the importance of incorporating epidemiological study results with other investigative findings.

Repair of an interstrand DNA cross-link initiated by ERCC1-XPF repair/recombination nuclease.

Interstrand DNA cross-link damage is a severe challenge to genomic integrity. Nucleotide excision repair plays some role in the repair of DNA cross-links caused by psoralens and other agents. However, in mammalian cells there is evidence that the ERCC1-XPF nuclease has a specialized additional function during interstrand DNA cross-link repair, beyond its role in nucleotide excision repair. We placed a psoralen monoadduct or interstrand cross-link in a duplex, 4-6 bases from a junction with unpaired DNA. ERCC1-XPF endonucleolytically cleaved within the duplex on either side of the adduct, on the strand having an unpaired 3' tail. Cross-links that were cleaved only on the 5' side were purified and reincubated with ERCC1-XPF. A second cleavage was then observed on the 3' side. Relevant partially unwound structures near a cross-link may be expected to arise frequently, for example at stalled DNA replication forks. The results show that the single enzyme ERCC1-XPF can release one arm of a cross-link and suggest a novel mechanism for interstrand cross-link repair.

A critique of the Model State Social Work Practice Act.

This article reviews the Model State Social Work Practice Act approved by the American Association of State Social Work Boards in 1998. The limitations of the definition of social work practice included in the model stature, inclusion of BSWs and social workers employed by public and nonprofit agencies, the promulgation of dual codes of ethics, and lack of assurance of effective services are discussed. Strategies for political action to benefit consumers, the public, and social workers are provided.

Xeroderma pigmentosum group F caused by a defect in a structure-specific DNA repair endonuclease.

Nucleotide excision repair, which is defective in xeroderma pigmentosum (XP), involves incision of a DNA strand on each side of a lesion. We isolated a human gene homologous to yeast Rad1 and found that it corrects the repair defects of XP group F as well as rodent groups 4 and 11. Causative mutations and strongly reduced levels of encoded protein were identified in XP-F patients. The XPF protein was purified from mammalian cells in a tight complex with ERCC1. This complex is a structure-specific endonuclease responsible for the 5' incision during repair. These results demonstrate that the XPF, ERCC4, and ERCC11 genes are equivalent, complete the isolation of the XP genes that form the core nucleotide excision repair system, and solve the catalytic function of the XPF-containing complex.

Enhancement of damage-specific DNA binding of XPA by interaction with the ERCC1 DNA repair protein.

The human XPA and ERCC1 proteins, which are involved in early steps of nucleotide excision repair of DNA, specifically interacted in an in vitro binding assay and a yeast two-hybrid assay. A stretch of consecutive glutamic acid residues in XPA was needed for binding to ERCC1. Binding of XPA to damaged DNA was markedly increased by the interaction of the XPA and ERCC1 proteins. ERCC1 did not enhance binding to DNA when a truncated XPA protein, MF122, was used in place of the XPA protein. MF122 retains damaged DNA binding activity but lacks the region for protein-protein interaction including the E-cluster region. These results suggest that the XPA/ERCC1 interaction may participate in damage-recognition as well as in incision at the 5' site of damage during nucleotide excision repair.

Mammalian DNA nucleotide excision repair reconstituted with purified protein components.

Nucleotide excision repair is the principal way by which human cells remove UV damage from DNA. Human cell extracts were fractionated to locate active components, including xeroderma pigmentosum (XP) and ERCC factors. The incision reaction was then reconstituted with the purified proteins RPA, XPA, TFIIH (containing XPB and XPD), XPC, UV-DDB, XPG, partially purified ERCC1/XPF complex, and a factor designated IF7. UV-DDB (related to XPE protein) stimulated repair but was not essential. ERCC1- and XPF-correcting activity copurified with an ERCC1-binding polypeptide of 110 kDa that was absent in XP-F cell extract. Complete repair synthesis was achieved by combining these factors with DNA polymerase epsilon, RFC, PCNA, and DNA ligase I. The reconstituted core reaction requires about 30 polypeptides.

Co-correction of the ERCC1, ERCC4 and xeroderma pigmentosum group F DNA repair defects in vitro.

The mammalian ERCC1-encoded polypeptide is required for nucleotide excision repair of damaged DNA and is homologous to Saccharomyces cerevisiae RAD10, which functions in repair and mitotic intrachromosomal recombination. Rodent cells representing repair complementation group 1 have nonfunctional ERCC1. We report that repair of UV-irradiated DNA can be reconstituted by combining rodent group 1 cell extracts with correcting protein from HeLa cells. Background repair was minimized by employing fractionated rodent cell extracts supplemented with human replication proteins RPA and PCNA. Group 1-correcting activity has a native molecular mass of 100 kDa and contains the 33 kDa ERCC1 polypeptide, as well as complementing activities for extracts from rodent group 4 and xeroderma pigmentosum group F (XP-F) cells. Extracts of group 1, group 4 or XP-F cells do not complement one another in vitro, although they complement extracts from other groups. The amount of ERCC1 detectable by immunoblotting is reduced in group 1, group 4 and XP-F extracts. Recombinant ERCC1 from Escherichia coli only weakly corrected the group 1 defect. The data suggest that ERCC1 is part of a functional protein complex with group 4 and XP-F correcting activities. The latter two may be equivalent to one another and analogous to S. cerevisiae RAD1.

Requirement for ERCC-1 and ERCC-3 gene products in DNA excision repair in vitro. Complementation using rodent and human cell extracts.

Numerous rodent cell lines exist that have defects in nucleotide excision repair of DNA caused by alterations in genes that fall into 10 different complementation groups. The precise roles in the repair of these genes are unknown. We report here that extracts from Chinese hamster ovary cells of excision repair-defective complementation groups 1 and 3 are defective in DNA excision repair in a cell-free system. In vitro complementation can be achieved by mixing extracts from the two groups with one another. In addition, extracts from a human cell line representing xeroderma pigmentosum complementation group B could complement rodent complementation group 1 extracts, but not group 3 extracts. This is consistent with an identity of the ERCC-3 and xeroderma pigmentosum group B genes. Cellular evidence points toward a defect in the incision of damaged DNA in group 1 and 3 mutants. Since the ERCC-1 and ERCC-3 proteins are required for the in vitro reaction, it appears that both gene products are directly involved in the enzymatic incision of damaged DNA, or in preincision reactions. The experiments reported here provide the biochemical basis of an approach to analyze the function of these nucleotide excision repair proteins.

Complementation of DNA repair in xeroderma pigmentosum group A cell extracts by a protein with affinity for damaged DNA.

Complementation group A of xeroderma pigmentosum (XP) represents one of the most prevalent and serious forms of this cancer-prone disorder. Because of a marked defect in DNA excision repair, cells from individuals with XP-A are hypersensitive to the toxic and mutagenic effects of ultraviolet light and many chemical agents. We report here the isolation of the XP-A DNA repair protein by complementation of cell extracts from a repair-defective human XP-A cell line. XP-A protein purified from calf thymus migrates on denaturing gel electrophoresis as a doublet of 40 and 42 kilodaltons. The XP-A protein binds preferentially to ultraviolet light-irradiated DNA, with a preference for damaged over nondamaged nucleotides of approximately 10(3). This strongly suggests that the XP-A protein plays a direct role in the recognition of and incision at lesions in DNA. We further show that this protein corresponds to the product encoded by a recently isolated gene that can restore excision repair to XP-A cells. Thus, excision repair of plasmid DNA by cell extracts sufficiently resembles genomic repair in cells to reveal accurately the repair defect in an inherited disease. The general approach described here can be extended to the identification and isolation of other human DNA repair proteins.

Effect of exogenous DNA fragments on human cell extract-mediated DNA repair synthesis.

Extracts from HeLa cells were used to study the susceptibility of repair synthesis in UV-irradiated plasmid DNA to inhibition by exogenously added nucleic acid. Purified DNA restriction fragments have little inhibitory effect on repair synthesis. However, activated calf thymus DNA fragments, genomic DNA fragments in cell extracts, and sonicated plasmid DNA all inhibited repair synthesis. Degraded DNA fragments arising from E. coli during bacterial plasmid purification were found to be particularly inhibitory. tRNA is not a potent inhibitor of in vitro repair synthesis. In order to observe efficient DNA repair synthesis mediated by human cell extracts, it is essential to prepare highly purified closed circular plasmid DNA, and we describe a reliable method for doing so.

ELISA detection of human IgG subclass antibodies to Streptococcus mutans.

A sensitive enzyme-linked immunosorbent assay (ELISA) has been developed to measure IgG subclass antibodies against whole cells of Streptococcus mutans and to a purified streptococcal antigen (SA I/II). Bacterial cells were bound to the solid phase using methyl glyoxal and mouse monoclonal antisera against IgG and each IgG subclass were used to detect antibodies. Natural antibodies to S. mutans were predominantly of the IgG1 and IgG2 subclasses, though IgG3 and IgG4 antibodies were detectable in most subjects, and were the majority response in a few subjects. Antibodies to SA I/II were predominantly of the IgG1 subclass with virtually no activity detectable in the IgG3 and IgG4 subclasses. Inhibition studies suggested some restriction of IgG subclass responses to bacterial antigens since SA I/II and c polysaccharide could inhibit binding of all subclasses to whole cells of S. mutans equally, whereas glucosyltransferase, lipoteichoic acid and dextran showed greatest inhibition of the IgG3 and IgG4 subclasses.

Immunological and histochemical analysis of regional variations of epidermal Langerhans cells in normal human skin.

Epidermal Langerhans' cells (LC) were enumerated in normal human skin from various anatomical sites using a monoclonal antibody (NA1/34) to human thymocyte antigen (HTA-1) and the standard ATPase reaction on frozen sections. The same population of cells was identified with each technique. LC densities were found to be significantly higher in hair bearing skin than in skin from the palm and sole. LC were also identified in hair follicles (where the numbers decreased from the superficial to the deep portions) and sebaceous glands but in no other adnexal structure. Normal numbers were encountered in patients who had received radiotherapy or systemic chemotherapy for malignant disease for periods of greater than two months before death. As LC are important antigen presenting cells, the variation in their density suggests that the immunological properties of normal skin may not be uniform throughout the body. This may be related to the varying anatomical distribution of some skin disorders with an immunological basis.