Outbreak of giardiasis associated with a community drinking-water source.

Giardiasis is a common waterborne gastrointestinal illness. In 2007, a community giardiasis outbreak occurred in New Hampshire, USA. We conducted a cohort study to identify risk factors for giardiasis, and stool and environmental samples were analysed. Consuming tap water was significantly associated with illness (risk ratio 4.7, 95% confidence interval 1.5-14.4). Drinking-water samples were coliform-contaminated and a suspect Giardia cyst was identified in a home water filter. One well was coliform-contaminated, and testing indicated that it was potentially under the influence of surface water. The well was located 12.5 m from a Giardia-contaminated brook, although the genotype differed from clinical specimens. Local water regulations require well placement at least 15 m from surface water. This outbreak, which caused illness in 31 persons, represents the largest community drinking-water-associated giardiasis outbreak in the USA in 10 years. Adherence to well placement regulations might have prevented this outbreak.

Are insurance companies liable under the Americans with Disabilities Act?

Federal courts have split on the question of the applicability of the Americans with Disabilities Act to insurance coverage decisions that insurance companies make on the basis of disability; they have similarly split on other issues pertaining to the scope of that Act's application. In deciding whether to read the Act as prohibiting discrimination in insurance decisions that are often crucial in the lives of people with disabilities, courts have faced two problems. First, where it prohibits discrimination in the equal enjoyment of the goods and services of places of public accommodation, the Act's area of concern may be limited to the ability of people with disabilities to gain physical access to facilities; or that area may extend to all forms of disability-based discrimination in the provision of goods and services. This Comment argues that the language and legislative history of the Act are consistent only with the latter view. Second, the provision limiting the Act's applicability to insurance may create an exemption for all insurance decisions; or it may protect only the ability of an insurance company to make an insurance decision to the disadvantage of an insured with a disability where actuarial data support the decision. This comment argues that the ambiguous language of the limiting provision should be resolved in favor of the latter view. Legislative history and the broader background of the history of insurance discrimination law support this resolution. Consequently, the Act should be interpreted as prohibiting disability-based discrimination by insurance companies in selling insurance policies and as defining discrimination as making disability-based insurance decisions without the support of actuarial data. By accepting this interpretation, courts can help stop the pattern of judicial narrowing of the Act's application through inappropriately restrictive statutory construction.

The role of bipolarity in depression in the family practice setting.

The literature suggests that bipolar spectrum disorders are more prevalent than previously thought but still poorly recognized. In the primary care setting, this poor recognition is largely the result of an insensitive, cross-sectional approach and clinicians' lack of familiarity with the phenomenology of bipolar II. Failure to recognize the role of bipolarity in depressive illness is more often a cause of the poor outcome of this illness in this setting than under dosing with antidepressants. Hypomania is easily missed in clinical evaluations and, as currently defined by DSM-IV, may not represent the most diagnostic marker for all variants of bipolar illness: Mood lability and energetic activity, temperamental traits embodied in the construct of cyclothymia, have emerged as more specific. Given emerging data that as much as one third of depressions in both psychiatric and primary care settings belong to the soft bipolar spectrum, practitioner education on the necessity to consider course, temperament, and family history in the approach to depression may improve the identification of bipolar spectrum disorders and limit unproductive or potentially harmful antidepressants use unprotected with mood stabilizers.

The bipolar spectrum: a review of current concepts and implications for the management of depression in primary care.

Family physicians inevitably encounter patients with bipolar disorders, often when the patient is depressed. For most of these patients, the attendant elevations in mood fall short of mania. Such milder periods of expansive mood, hypomanias, may go unrecognized unless the physician specifically queries the patient to uncover them. In addition, patients with bipolar disorders often manifest other distinctive characteristics. An understanding of these hints of bipolarity is helpful to clinicians treating depressive illness. Patients with bipolar disorders are at risk for treatment complications caused by the administration of antidepressants without the concurrent use of mood stabilizers, such as lithium carbonate, valproate sodium, and carbamazepine. Such complications include exacerbation of hypomania or mania, induction of refractory states, and, perhaps, rapid cycling or mixed states. We review current issues in classification of bipolar disorders and emphasize the importance of identifying hypomania. An introduction to the concept of affective temperaments and a brief review of treatment strategies and treatment complications are included.

On the nature of depressive and anxious states in a family practice setting: the high prevalence of bipolar II and related disorders in a cohort followed longitudinally.

Much of the scientific literature on affective states in primary care settings is derived from instrument-based diagnoses, typically without the benefit of clinical in-depth examination. In a naturalistic family practice setting, we prospectively evaluated 108 consecutive anxious and/or depressed patients. All diagnoses derived from semistructured interviews conducted by a family physician with enhanced training in mood disorders. Nonbipolar depressions were found in 60 of 108 patients (55.6%), nearly half of whom were in the depression not otherwise specified (DNOS) category; yet on careful history, all but two of 28 DNOS cases had major depressive episodes in the past. Twenty-eight patients (25.9%) were diagnosed with bipolar I, II, or III disorder or cyclothymia. Panic disorder was found in 9%, and obsessive-compulsive disorder and active chemical dependency were each diagnosed in 3%. Bipolar spectrum disorders were common (one in three within the depressive group) and at times were not recognized until several weeks or months into the treatment phase of the depressed or anxious state. Although the largest percentage of patients had DNOS at the index episode, bipolar illness (usually bipolar II) was also common. Our findings contrast with the nearly total unipolarity reported in the instrument-based (nonclinician) literature. If generalizable, our observations have significant implications for physician education and practice, since bipolar depressions require different interventions. Further investigation to explore interview approaches and/or instruments sensitive for hypomania and other "soft" bipolar features seems warranted.

Antidepressant augmentation with lithium.

Depression is one of the most prevalent disorders seen in primary care. About 50% of depression is treated in general medical settings. Although depression is highly treatable, incomplete response to a single antidepressant is common. We describe two clinical cases in which antidepressant augmentation was a therapeutic option and lithium carbonate was an appropriate choice. A brief review of the practical aspects of the clinical pharmacology of lithium is included. Lithium is a well-tolerated, safe, and effective medication for antidepressant augmentation.

A phosphorylated 34-kDa protein and a subpopulation of polyhedrin are thiol linked to the carbohydrate layer surrounding a baculovirus occlusion body.

Surrounding baculovirus occlusion bodies is an electron-dense layer reported to be composed of carbohydrate which we term calyx. Incubation of Autographa californica nuclear polyhedrosis virus occlusion bodies (AcMNPV OBs) with dilute alkaline saline (DAS) followed by centrifugation at 12,000 g resulted in the sedimentation of calyx material which contained pp34, residual polyhedrin (p32), and entrapped occluded virions (DAS P-12 fraction). Incubation of the DAS P-12 fraction with sodium dodecyl sulfate (SDS) resulted in solubilization of the entrapped virions and the majority of p32, while calyx material, pp34, and some p32 remained sedimentable at 12,000 g. Immunofluorescence microscopy of DAS-solubilized OBs using monoclonal antibody to pp34 and p32 revealed that both pp34 and p32 are closely associated with the calyx. When DAS P-12 fractions were resuspended in SDS and reducing agent, not only were the entrapped virions solubilized, but pp34 and the remaining p32 were also liberated, indicating that pp34 and a subpopulation of p32 are associated with the calyx via thiol linkages. Immunoblot analysis and peptide mapping demonstrated that pp34 is neither immunologically nor structurally related to p32. The kinetics of pp34 synthesis were also examined by immunoprecipitation of infected cell polypeptides using pp34-specific monoclonal antibody. pp34 was detected initially 15 hr postinfection (p.i.) and continued to be phosphorylated until 60-70 hr p.i. This study demonstrates that the AcMNPV calyx has a proteinaceous component and we propose that other occluded baculoviruses may also have a calyx-associated protein analogous to pp34.

Identification of the thymidine kinase gene of infectious bovine rhinotracheitis virus and its function in Escherichia coli hosts.

In an attempt to understand the gene expression of the infectious bovine rhinotracheitis virus (IBRV), the viral thymidine kinase gene (tk), a well regulated viral gene has been chosen for this study. A cosmid library of IBRV has been constructed in Escherichia coli HB101 by cloning partially Sau3A-digested DNA fragments into a cosmid vector, pJB8. Recombinant cosmids were further analyzed by restriction digestions and by Southern blot hybridization. Results showed that this cosmid library comprised all of the IBRV genome with the exception of both termini. The individual recombinant cosmid clones were then used to transform E. coli tdk- mutant strains, Ky895 or C600tdk- for the selection of the IBRV tk gene. The clones able to grow on the selection plates containing 5-fluorouracil, uridine, thymidine and ampicillin were selected and further characterized. The physical location of the viral DNA inserts of one of the clones, pIBR5, was determined and the sequences complementing the tk activity have been isolated by subcloning. The plasmid, pIBRTK, was shown to grow on selection plates and therefore, retained the ability to complement the tk gene. The E. coli mutant strain C600tdk- harboring pIBRTK partially restores the tk activity by exhibiting a three and half fold increase in the level of the incorporation of [3H]thymidine into bacterial DNA over that of C600tdk- mutant.

Coordination of cleavage of gag and env gene products of murine leukemia virus: implications regarding the mechanism of processing.

Mouse 3T6 cells infected with Murine Leukemia Virus (MuLV) were cloned to yield several sublines producing viruses distinct from one another with respect to the ratio of uncleaved to cleaved gag gene-coded polyprotein, Pr65gag. The virus produced by the cloned sublines also differed in the ratio of the env gene-coded protein, p15E, to its product, p12E. The two ratios, Pr65gag/p30 and p15E/p12E, were found to be highly correlated among the cloned cell lines. Velocity gradient separation of the virions produced by individual sublines, followed by polypeptide analysis, demonstrated that the particles were inhomogeneous with respect to extent of cleavage both of PR65gag and of p15E. The two cleavages were again highly correlated. These data indicate that the gag and env gene product cleavages are not independent events but are tightly coupled.

Bluetongue virus: comparative evaluation of enzyme-linked immunosorbent assay, immunodiffusion, and serum neutralization for detection of viral antibodies.

Comparative studies on the detection of bovine serum immunoglobulin G antibodies to bluetongue virus with an enzyme-linked immunosorbent assay, an immunodiffusion method, and a serum neutralization assay demonstrated complete concordance between the enzyme-linked immunosorbent assay and the serum neutralization assay results. However, the immunodiffusion method failed to detect bluetongue virus antibody in a substantial number of sera found to possess bluetongue virus immunoglobulin G with the enzyme-linked immunosorbent assay.

Bioactivities and the effect of dilution on various milk-borne murine mammary tumor viruses.

Infectivity titrations of milk-borne murine mammary tumor virus (MuMTV) from different sources or prepared in different ways or stored for periods of time have been compared. Titration curves were in general reproducible for MuMTVs of different sources or handled in different ways and for different methods of measurement, such as hyperplastic alveolar nodule (HAN) development, tumor development, or MuMTV antigen secretion in third-lactation milk, The curves had characteristic shapes with a low incidence of infection at low dilutions of milk, high incidences at intermediate dilutions, and low incidences at high dilutions. Infectivity incidences were unaffected by dilution over the range 10(-2) to 10(-5). The curves did not change appreciably with time of storage of milk at liquid N2 temperature for periods up to 3 years. Rate zonal fractionation of RIII milk gave zones with bioactivities which were not proportional to B-particle content. Upon dilution, the bioactivity of Zone 3, rich in B particles, and Zone 5, poor in B particles, increased, while the bioactivity of all the other zones usually decreased with dilution. The low incidence of infection at low dilutions may have been due, in part, to an immune response of the inoculated mouse. Administration of inactivated virions 4 h prior to or with MuMTV inoculations gave some evidence in support of this hypothesis but the complexity of the bioassay system for MuMTV lends uncertainty to interpretation of results.

Effects of cell culture and laboratory conditions on type 2 dengue virus infectivity.

The stability of type 2 dengue virus to exposure to a variety of laboratory conditions was determined. Suckling mouse brain passage virus was adapted for growth in BHK-21 cells, and plaque assays were performed using a tragacanth gum overlay. A three- to fourfold increase in plaque size could be obtained if monolayers were subconfluent at time of inoculation. Incubation of virus for 24 h at 37 degrees C, pH 6.5, or in buffer containing 1 mM ethylenediaminetetraacetate considerably reduced virus infectivity as compared with virus incubated for the same period at 4 degrees C, pH 8.0, or in buffer with or without 1 mM CaCl2 and 1 mM MgCl2. Multiple freezing and thawing of virus tissue culture medium containing 10% fetal calf serum did not reduce virus infectivity.

Cellular immunologic studies of malignant lymphoma in rhesus macaques.

Cells from malignant lymphoma in 10 rhesus macaques were examined for lymphocyte surface markers. Three had features of T cells, 5 had features of B cells, and 2 lacked evidence of either B- or T-cell differentiation. Correlation between the histologic classification of cell type and the B- or T-cell nature of the neoplasms was not evident. Evaluation of serum electrophoresis, mitogen responses tests, and previous histologic studies suggest that the development of the neoplastic lymphocyte proliferation occurred following or during an abnormal immunologic response.

Viruses detected in cells explanted into tissue culture from naturally occurring malignant lymphoma in rhesus monkeys.

During a 4-year period 43 cases of spontaneous lymphoma occurred in macaques at the California Primate Research Center. In an attempt to determine if there might be a common viral etiology to the outbreak, lymphoma tissues from 10 rhesus monkeys were explanted into tissue culture and examined for the presence of virus. Electron microscopic studies of the cultured lymphoma cells revealed viruses morphologically characteristics of adenovirus, reovirus, foamy virus, and herpesvirus. Cell-free filtrates from tissue cultures possessing the latter three viruses produced cytopathology in virus-free indicator cells. Virus particles typical of the explant culture were demonstrable in the infected indicator cells. Type-C RNA tumor virus particles were not observed electron microscopically in any of the lymphoma tissues or lymphoma cell cultures examined.

Malignant lymphoma with B-lymphocyte characteristics in dogs.

Cell surface membrane characteristics of B and T lymphocytes were demonstrated on cells from canine malignant lymphoma, and the results were compared with cytologic classification. Lymphoma in 4 of 5 dogs was found to have one or more characteristics of B lymphocytes. Correlation between the cytologic classification and the presence of B- and T-lymphocyte characteristics was not apparent.