A distinct isoform of lymphoid enhancer binding factor 1 (LEF1) epigenetically restricts EBV reactivation to maintain viral latency.

As a human tumor virus, EBV is present as a latent infection in its associated malignancies where genetic and epigenetic changes have been shown to impede cellular differentiation and viral reactivation. We reported previously that levels of the Wnt signaling effector, lymphoid enhancer binding factor 1 (LEF1) increased following EBV epithelial infection and an epigenetic reprogramming event was maintained even after loss of the viral genome. Elevated LEF1 levels are also observed in nasopharyngeal carcinoma and Burkitt lymphoma. To determine the role played by LEF1 in the EBV life cycle, we used in silico analysis of EBV type 1 and 2 genomes to identify over 20 Wnt-response elements, which suggests that LEF1 may bind directly to the EBV genome and regulate the viral life cycle. Using CUT&RUN-seq, LEF1 was shown to bind the latent EBV genome at various sites encoding viral lytic products that included the immediate early transactivator BZLF1 and viral primase BSLF1 genes. The LEF1 gene encodes various long and short protein isoforms. siRNA depletion of specific LEF1 isoforms revealed that the alternative-promoter derived isoform with an N-terminal truncation (ΔN LEF1) transcriptionally repressed lytic genes associated with LEF1 binding. In addition, forced expression of the ΔN LEF1 isoform antagonized EBV reactivation. As LEF1 repression requires histone deacetylase activity through either recruitment of or direct intrinsic histone deacetylase activity, siRNA depletion of LEF1 resulted in increased histone 3 lysine 9 and lysine 27 acetylation at LEF1 binding sites and across the EBV genome. Taken together, these results indicate a novel role for LEF1 in maintaining EBV latency and restriction viral reactivation via repressive chromatin remodeling of critical lytic cycle factors.

Retinoblastoma Protein Is Required for Epstein-Barr Virus Replication in Differentiated Epithelia.

Coinfection of human papillomavirus (HPV) and Epstein-Barr virus (EBV) has been detected in oropharyngeal squamous cell carcinoma. Although HPV and EBV replicate in differentiated epithelial cells, we previously reported that HPV epithelial immortalization reduces EBV replication within organotypic raft culture and that the HPV16 oncoprotein E7 was sufficient to inhibit EBV replication. A well-established function of HPV E7 is the degradation of the retinoblastoma (Rb) family of pocket proteins (pRb, p107, and p130). Here, we show that pRb knockdown in differentiated epithelia and EBV-positive Burkitt lymphoma (BL) reduces EBV lytic replication following de novo infection and reactivation, respectively. In differentiated epithelia, EBV immediate early (IE) transactivators were expressed, but loss of pRb blocked expression of the early gene product, EA-D. Although no alterations were observed in markers of epithelial differentiation, DNA damage, and p16, increased markers of S-phase progression and altered p107 and p130 levels were observed in suprabasal keratinocytes after pRb knockdown. In contrast, pRb interference in Akata BX1 Burkitt lymphoma cells showed a distinct phenotype from differentiated epithelia with no significant effect on EBV IE or EA-D expression. Instead, pRb knockdown reduced the levels of the plasmablast differentiation marker PRDM1/Blimp1 and increased the abundance of c-Myc protein in reactivated Akata BL with pRb knockdown. c-Myc RNA levels also increased following the loss of pRb in epithelial rafts. These results suggest that pRb is required to suppress c-Myc for efficient EBV replication in BL cells and identifies a mechanism for how HPV immortalization, through degradation of the retinoblastoma pocket proteins, interferes with EBV replication in coinfected epithelia. IMPORTANCE Terminally differentiated epithelium is known to support EBV genome amplification and virion morphogenesis following infection. The contribution of the cell cycle in differentiated tissues to efficient EBV replication is not understood. Using organotypic epithelial raft cultures and genetic interference, we can identify factors required for EBV replication in quiescent cells. Here, we phenocopied HPV16 E7 inhibition of EBV replication through knockdown of pRb. Loss of pRb was found to reduce EBV early gene expression and viral replication. Interruption of the viral life cycle was accompanied by increased S-phase gene expression in postmitotic keratinocytes, a process also observed in E7-positive epithelia, and deregulation of other pocket proteins. Together, these findings provide evidence of a global requirement for pRb in EBV lytic replication and provide a mechanistic framework for how HPV E7 may facilitate a latent EBV infection through its mediated degradation of pRb in copositive epithelia.

Particle size as a driver of dewatering performance and its relationship to stabilization in fecal sludge.

Poor and unpredictable dewatering performance of fecal sludge is a major barrier to sanitation provision in urban areas not served by sewers. Fecal sludge comprises everything that accumulates in onsite containments, and its characteristics are distinct from wastewater sludges and from feces. There is little fundamental understanding of what causes poor dewatering in fecal sludge. For the first time, we demonstrate that particle size distribution is a driver of dewatering performance in fecal sludge, and is associated with level of stabilization. Higher concentrations of small particles (<10 µm) and smaller median aggregate size (D50) corresponded to poor dewatering performance (measured by capillary suction time (CST) and supernatant turbidity) in field samples from Kenya and Uganda and in controlled laboratory anaerobic storage experiments. More stabilized fecal sludge (higher C/N, lower VSS/TSS) had better dewatering performance, corresponding to lower concentrations of small particles. Samples with the largest aggregates (D50 > 90 µm) had higher abundance of Gammaproteobacteria Pseudomonas, and samples with the smallest aggregates (D50 ≤ 50 µm) were characterized by higher abundance of Bacteroidetes Vadin HA17 and Rikenellaceae. Contrary to common perceptions, stabilization, particle size distribution, and dewatering performance were not dependent on time intervals between emptying of onsite containments or on time in controlled anaerobic storage experiments. Our results suggest that the stabilization process in onsite containments, and hence the dewaterability of sludge arriving at treatment facilities, is not dependent on time in containment but is more likely associated with specific microbial populations and the in-situ environmental conditions which promote or discourage their growth.

EBV Association with Lymphomas and Carcinomas in the Oral Compartment.

Epstein-Barr virus (EBV) is an oncogenic human herpesvirus infecting approximately 90% of the world's population. The oral cavity serves a central role in the life cycle, transmission, and pathogenesis of EBV. Transmitted to a new host via saliva, EBV circulates between cellular compartments within oral lymphoid tissues. Epithelial cells primarily support productive viral replication, while B lymphocytes support viral latency and reactivation. EBV infections are typically asymptomatic and benign; however, the latent virus is associated with multiple lymphomas and carcinomas arising in the oral cavity. EBV association with cancer is complex as histologically similar cancers often test negative for the virus. However, the presence of EBV is associated with distinct features in certain cancers. The intrinsic ability of EBV to immortalize B-lymphocytes, via manipulation of survival and growth signaling, further implicates the virus as an oncogenic cofactor. A distinct mutational profile and burden have been observed in EBV-positive compared to EBV-negative tumors, suggesting that viral infection can drive alternative pathways that converge on oncogenesis. Taken together, EBV is also an important prognostic biomarker that can direct alternative therapeutic approaches. Here, we discuss the prevalence of EBV in oral malignancies and the EBV-dependent mechanisms associated with tumorigenesis.

Spatio-temporal variations and age effect on Toxoplasma gondii seroprevalence in seals from the Canadian Arctic.

Toxoplasmosis is a significant public health threat for Inuit in the Canadian Arctic. This study aimed to investigate arctic seals as a possible food-borne source of infection. Blood samples collected from 828 seals in 7 Canadian Arctic communities from 1999 to 2006 were tested for Toxoplasma gondii antibodies using a direct agglutination test. Polymerase chain reaction (PCR) was used to detect T. gondii DNA in tissues of a subsample of seals. Associations between seal age, sex, species, diet, community and year of capture, and serological test results were investigated by logistic regression. Overall seroprevalence was 10·4% (86/828). All tissues tested were negative by PCR. In ringed seals, seroprevalence was significantly higher in juveniles than in adults (odds ratio=2·44). Overall, seroprevalence varied amongst communities (P=0·0119) and by capture year (P=0·0001). Our study supports the hypothesis that consumption of raw seal meat is a significant source of infection for Inuit. This work raises many questions about the mechanism of transfer of this terrestrial parasite to the marine environment, the preponderance of infection in younger animals and the natural course of infection in seals. Further studies to address these questions are essential to fully understand the health risks for Inuit communities.

High-yield amplification of Cryptosporidium parvum in interferon gamma receptor knockout mice.

To date, large-scale production of Cryptosporidium parvum oocysts has only been achieved by amplification in neonatal calves and sheep. Many laboratories currently depend on supplies from external sources and store oocysts for prolonged periods which results in progressive loss of viability. Six to 8-week-old interferon gamma receptor knockout (IFN gamma R-KO) mice on a C57BL/6 background were inoculated by gavage (2000 oocysts/animal). Fecal pellets were collected daily from 7 days post-infection (p.i.) up to 2 weeks p.i. Intestinal oocyst yield was assessed at days 11, 12 and 14 p.i. by homogenization of intestinal tissues. Ether extraction and one or more NaCl flotations were used to purify oocysts. Total recoveries averaged 2.6 x 10(6) oocysts/mouse from fecal material and 3.8 x 10(7) oocysts/mouse from intestinal tissues. Overall, 2.3 x 10(9) purified oocysts were obtained from 60 mice. Recovered oocysts were capable of sporulation and were shown to be infectious both in vitro and in vivo. Oocyst amplification was achieved in only 11-14 days with minimal expense. The simplicity of this method presents a practical alternative for the routine passage, maintenance and storage of C. parvum in biomedical laboratories.

Travellers and influenza: risks and prevention.

BACKGROUND: Influenza viruses are among the major causes of serious human respiratory tract infection worldwide. In line with the high disease burden attributable to influenza, these viruses play an important, but often neglected, role in travel medicine. Guidelines and recommendations regarding prevention and management of influenza in travellers are scarce. Of special interest for travel medicine are risk populations and also circumstances that facilitate influenza virus transmission and spread, like travel by airplane or cruise ship and mass gatherings. METHODS: We conducted a PUBMED/MEDLINE search for a combination of the MeSH terms Influenza virus, travel, mass gathering, large scale events and cruise ship. In addition we gathered guidelines and recommendations from selected countries and regarding influenza prevention and management in travellers. By reviewing these search results in the light of published knowledge in the fields of influenza prevention and management, we present best practice advice for the prevention and management of influenza in travel medicine. RESULTS: Seasonal influenza is among the most prevalent infectious diseases in travellers. Known host-associated risk factors include extremes of age and being immune-compromised, while the most relevant environmental factors are associated with holiday cruises and mass gatherings. CONCLUSIONS: Pre-travel advice should address influenza and its prevention for travellers, whenever appropriate on the basis of the epidemiological situation concerned. Preventative measures should be strongly recommended for travellers at high-risk for developing complications. In addition, seasonal influenza vaccination should be considered for any traveller wishing to reduce the risk of incapacitation, particularly cruise ship crew and passengers, as well as those participating in mass gatherings. Besides advice concerning preventive measures and vaccination, advice on the use of antivirals may be considered for some travellers.

Randomized, double-blind clinical trial of topical imiquimod 5% with parenteral meglumine antimoniate in the treatment of cutaneous leishmaniasis in Peru.

BACKGROUND: Current treatments for cutaneous leishmaniasis are limited by their toxicity, high cost, and discomfort and the emergence of drug resistance. New approaches, including combination therapies, are urgently needed. We performed a double-blind, randomized trial of therapy with parenteral antimony plus topical imiquimod, an innate immune-response modulator, versus therapy with antimony alone, in subjects with cutaneous leishmaniasis for whom an initial course of antimony therapy had failed. METHODS: Forty subjects with clinical resistance to antimony were recruited in Lima, Peru, between February 2001 and December 2002. All subjects received meglumine antimoniate (20 mg/kg/day im or iv) and were randomized to receive either topical imiquimod 5% cream (Aldara; 3M Pharmaceuticals) or vehicle control every other day for 20 days. Lesions and adverse events were evaluated during treatment and at 1, 2, 3, 6, and 12 months after the treatment period. RESULTS: The mean number of lesions was 1.2 per person; 71% of the lesions were facial and 76% were ulcerative. There were no major differences between the groups, and all but 2 subjects completed therapy. Mild adverse events were reported by 73% of the subjects, but only erythema occurred more commonly in the imiquimod group (P < or = .02). Lesions resolved more rapidly in the imiquimod group: 50% of the imiquimod group achieved cure at 1 month after the treatment period versus 15% of the vehicle cream group (P < or = .02); 61% of the imiquimod group at 2 months versus 25% of the vehicle cream group (P < or = .03); and 72% of the imiquimod group at 3 months versus 35% of the vehicle cream group (P < or = .02). Residual scarring in the imiquimod group was less prominent than in the vehicle cream group. CONCLUSIONS: Combined antimony plus imiquimod treatment was well tolerated, accelerated healing of lesions, and improved scar quality. This therapy may have particular advantages for subjects with facial lesions.

Hypoxia induced disruption of the cardiac endothelial glycocalyx: implications for capillary permeability.

OBJECTIVE: The aim was to determine the effect of hypoxia on the ultrastructure of the endothelial glycocalyx of cardiac capillaries. METHODS: Isolated rat hearts were perfused with oxygenated or hypoxic Krebs solution for 30 min after equilibration with oxygenated medium. They were then perfused with a cationic marker (ruthenium red, lanthanum nitrate, or cationised ferritin) to delineate the cardiac endothelial glycocalyx in the electron microscope. With ruthenium red and lanthanum, perfusions were carried out both in the presence and absence of bovine serum albumin. Ferritin perfused hearts were used to quantify changes in the glycocalyx as a result of hypoxia and to measure the cross sectional area of the endothelial cells. RESULTS: In all the hearts perfused with well oxygenated solution, all three markers showed an even, electron dense layer on the luminal surface of the capillaries. With ruthenium red and lanthanum (but not with ferritin), the marker was occasionally observed throughout the length of the interendothelial clefts and on the albuminal surface. After 30 min hypoxic perfusion, both ruthenium red and lanthanum showed disruption and irregular clumping of the glycocalyx, with or without albumin. Ferritin, however, showed a sparse and uneven layer. Measurements of endothelial cell area showed that some cells from hypoxic hearts were swollen when compared with controls. Measurements of the percentage of luminal membrane covered by ferritin molecules showed a significant loss of glycocalyx in hypoxic hearts. There was, however, no correlation between loss of glycocalyx and endothelial cell swelling. CONCLUSIONS: The endothelial cell glycocalyx of continuous capillaries is sensitive to changes in PO2. The disruption of this surface coat may explain the reported increase in capillary permeability in hypoxia.

Contraction in cardiac endothelial cells contributes to changes in capillary dimensions following ischaemia and reperfusion.

OBJECTIVE: Ischaemia followed by reperfusion brings about a reduction in cardiac capillary cross-sectional dimensions which is consistent with constriction. The aim of this study was to test the hypothesis that the reduction in cardiac capillary dimensions that occurs in ischaemia and reperfusion is caused by endothelial cell contraction and that modulating the endothelial cell contractile apparatus reduces microvascular reperfusion injury. METHODS: In isolated rat hearts we used phalloidin to stabilise the endothelial actin filaments in order to prevent the dimensional changes during ischaemia. The changes in endothelial cell dimensions were quantified by measuring whole capillary and luminal cross-sectional areas, abluminal and luminal membrane lengths. We have also used resin casts of the coronary vasculature coupled with scanning electron microscopy to examine the structural changes along the length of the capillaries in ischaemia-reperfusion. RESULTS: We found that the reduction in capillary dimensions was prevented by the addition of phalloidin and, in the resin casts, that ischaemia-reperfusion cause focal narrowings along the capillaries which are consistent with constriction. CONCLUSIONS: (1) The endothelial contractile apparatus is involved in the reduction in cross-sectional dimensions. (2) This implies that the capillary bed may have a greater role in the local control of flow than was previously thought and that modulation of the actomyosin contractile system in cardiac capillary endothelial cells may be useful in reducing 'no reflow' injury which results from reperfusion.

Plant-derived H7 VLP vaccine elicits protective immune response against H7N9 influenza virus in mice and ferrets.

In March 2013, the Chinese Centre for Disease Control and Prevention confirmed the first reported case of human infection with an avian influenza A H7N9 virus. Infection with this virus often caused severe pneumonia and acute respiratory distress syndrome resulting in a case fatality rate >35%. The risk of pandemic highlighted, once again, the need for a more rapid and scalable vaccine response capability. Here, we describe the rapid (19 days) development of a plant-derived VLP vaccine based on the hemagglutinin sequence of influenza H7N9 A/Hangzhou/1/2013. The immunogenicity of the H7 VLP vaccine was assessed in mice and ferrets after one or two intramuscular dose(s) with and without adjuvant (alum or GLA-SE™). In ferrets, we also measured H7-specific cell-mediated immunity. The mice and ferrets were then challenged with H7N9 A/Anhui/1/2013 influenza virus. A single immunization with the adjuvanted vaccine elicited a strong humoral response and protected mice against an otherwise lethal challenge. Two doses of unadjuvanted vaccine significantly increased humoral response and resulted in 100% protection with significant reduction of clinical signs leading to nearly asymptomatic infections. In ferrets, a single immunization with the alum-adjuvanted H7 VLP vaccine induced strong humoral and CMI responses with antigen-specific activation of CD3(+) T cells. Compared to animals injected with placebo, ferrets vaccinated with alum-adjuvanted vaccine displayed no weight loss during the challenge. Moreover, the vaccination significantly reduced the viral load in lungs and nasal washes 3 days after the infection. This candidate plant-made H7 vaccine therefore induced protective responses after either one adjuvanted or two unadjuvanted doses. Studies are currently ongoing to better characterize the immune response elicited by the plant-derived VLP vaccines. Regardless, these data are very promising for the rapid production of an immunogenic and protective vaccine against this potentially pandemic virus.

Effect of L-carnitine on cultured murine melanoma cells exposed to azelaic acid.

The cytotoxic effect of azelaic acid on murine melanoma cells in culture is due, at least in part, to an antimitochondrial action. We investigated the possibility that the addition of carnitine to the medium may increase the transport of azelaic acid into the mitochondria and thereby increase its cytotoxic effect. Using mitochondrial cross-sectional area measured from electron micrographs as a criterion for mitochondrial damage, we found that the addition of L-carnitine to the culture medium had no effect either alone or with a low (10(-3) M) concentration of azelaic acid. At a high concentration (5 X 10(-2) M) azelaic acid caused swelling and disruption of the mitochondria to such an extent that this was not increased by carnitine. At 10(-2) M azelaic acid, however, some swelling of the mitochondria occurred which was significantly increased by the addition of carnitine. This indicates that carnitine-mediated transport of the diacid into the mitochondria had occurred. We conclude that carnitine may reduce the time or concentration needed for azelaic acid to have a toxic effect on the malignant melanocyte.

Effect of dicarboxylic acids on Harding-Passey and Cloudman S91 melanoma cells in tissue culture.

Clinically, dicarboxylic acids have a cytotoxic effect on the abnormally hyperactive and malignant epidermal melanocyte, and diacids from C8 to C13 have been shown to inhibit mitochondrial oxidoreductases. Here, their effect on the growth kinetics and ultrastructure of murine melanoma cells in culture is examined. Cultures of Harding-Passey and Cloudman S91 melanoma cells were exposed to single doses of the disodium salts of C12, C9, and C6 (which does not significantly inhibit mitochondrial enzymes) dicarboxylic acids at concentrations of 10(-3) M to 10(-1) M. With C12 and C9, viability and cell proliferation over 3 days were significantly affected by concentrations greater than 10(-2) M. With exposure to C6 at 10(-1) M and to medium to which NaCl was added to produce equal osmolarity, the effect was much less. Electron microscopy of cells exposed to C9 at 10(-1) M for 1 h and 6 h revealed massive swelling of mitochondria with destruction of cristae, but plasma and nuclear membranes and membranes of endoplasmic reticulum were intact. Similar damage was not seen with C6 at 10(-1) M nor with equiosomolar NaCl. The results confirm (1) the cytotoxicity of dicarboxylic acids for malignant melanocytes, and (2) that the mitochondrion is a prime target for their action.

Mycobacterium ulcerans infection (Buruli ulcer): first reported case in a traveler.

A chronic, painless sore developed over a 2-month period on the left calf of a Canadian man traveling for 8 months in Africa. A presumptive diagnosis of a Mycobacterium spp. infection was made despite initially negative biopsy and culture results, after failure of several courses of anti-bacterial antibiotics. Mycobacterium ulcerans was eventually isolated and the lesion progressed despite treatment with multiple anti-mycobacterial agents. The lesion finally responded to wide and repeated excision, aggressive treatment with anti-mycobacterial antibiotics, and split-thickness skin grafting. The isolation and treatment of this unusual organism are discussed.

Wheat germ supplement reduces cyst and trophozoite passage in people with giardiasis.

The protozoan parasite Giardia lamblia is a major cause of waterborne enteric disease worldwide. Lectins are proteins that bind to carbohydrate (sugar) moieties. Potential targets for lectins are found on the surface of most single-celled organisms. Modest concentrations of wheat germ agglutinin (WGA) have been shown to inhibit G. lamblia excystation and trophozoite growth in vitro and can reduce cyst passage in mice infected with the closely related protozoan parasite, G. muris. Commercial preparations of wheat germ (WG) contain 13-53 microg of WGA per gram. We performed a double-masked, placebo-controlled study of dietary supplementation with WG in 63 subjects with giardiasis in Montreal and Lima (25 asymptomatic patients passing cysts; 38 patients with symptoms). Asymptomatic subjects received WG (2 g, 3 times a day) or placebo (cornstarch, 2 g, 3 times a day) for 10 days, followed by metronidazole (250 mg 3 times a day) for 7 days. Symptomatic subjects received metronidazole (250 mg 3 times a day) plus either WG or placebo for 7 days. Stool specimens were collected every day (Montreal) or every other day (Lima) for 10 days and on Day 35 for microscopic examination and coproantigen determination. Subjects kept a diary of symptoms for 10 days after recruitment. In asymptomatic subjects, both cyst passage and coproantigen levels were reduced by approximately 50% in those taking WG compared with the placebo group (P < 0.01 and P = 0.06, respectively). In symptomatic subjects, cyst passage and coproantigen levels fell precipitously in response to metronidazole therapy, and there were no clinically important differences between those receiving supplemental WG or placebo. However, symptoms appear to have resolved more rapidly in the subjects taking WG in addition to metronidazole. The WG supplement was well tolerated in both symptomatic and asymptomatic subjects. These data suggest that components of WG, possibly WGA, either alone or in combination with antiprotozoal agents, can influence the course of human giardiasis.

Measurement of measles virus-specific neutralizing antibodies: evaluation of the syncytium inhibition assay in comparison with the plaque reduction neutralization test.

Plaque reduction neutralization (PRN) is the "gold-standard" for the measurement of measles-specific neutralizing antibodies. However, it is a complicated assay and tends to be operator-dependent. It has been suggested that the simpler syncytium inhibition assay (SIA) can give results comparable to the PRN test. We compared these two assays using 594 serum or plasma samples obtained from children at various times after natural infection, primary measles immunization, and measles revaccination. The results of the two assays correlated well overall (r = .86; p < 0.0001). The strain of challenge virus (wild-type versus vaccine strain) did not significantly influence SIA titers and the assay performed equally well with serum and plasma. PRN titers > or = 120 and > 800 are thought to indicate protection against clinical illness and infection respectively. The equivalent SIA cut-off values using 125 plaque-forming units as the challenge inoculum were > or = 16 and > 128 respectively. At low PRN titers (< 200), the correlation between PRN and SIA values was reasonable (r = 0.60; p < 0.001) when a challenge inoculum of 12.5 plaque-forming units was used. At the lowest PRN titers (< 100), 15% of the samples gave divergent results. These data confirm the utility of the SIA in the determination of measles-specific neutralizing antibodies when antibody titers are high. However, the PRN assay remains the test of choice when maximum sensitivity at low titers is required.

Measles vaccines: a review of adverse events.

A great deal of controversy has recently been generated over the publication of several articles implicating measles vaccine in the induction of Crohn's disease and autism. The publication of this work has already had a negative impact on measles vaccine acceptance in the UK. These allegations are particularly troubling because they arise in the context of increased use of measles vaccine as global control of measles nears and the international community considers strategies for a drive towards eradication. In 1994, the US Institute of Medicine reviewed the world literature and published a comprehensive review of adverse events associated with measles-containing vaccines. Reviewing the literature published between 1994 and the present day, reveals that there is considerable new data suggesting that modified gelatin rather than egg proteins is responsible for most episodes of anaphylaxis following measles vaccination. New work weakens the possible links between measles vaccine and subacute sclerosing panencephalitis and Guillain-Barré syndrome, but strengthens the rare association of measles-containing vaccines with post infectious encephalomyelitis. The alleged associations between measles vaccination and Crohn's disease and autism are based upon weak science and have largely been refuted by a large volume of stronger work. A review of the data generated in the last 4 years amply demonstrates the continued efforts of the scientific community to monitor and understand true measles vaccine-associated adverse events. The rapidity and clarity of this same community's debunking of the spurious associations with Crohn's disease and autism suggests that those charged with vaccination programmes have learned from past mistakes. During 30 years of worldwide use, measles vaccination has proven to be one of the safest and most successful health interventions in the history of mankind. It is not a 'perfect' vaccine, but the benefits of measles vaccination far outweigh the risks even in countries with low incidence of measles and high rates of measles vaccine coverage.

Retinol (vitamin A) supplements in the elderly.

Aging is associated with many changes in epithelial tissues, immune function and haematopoiesis-myelopoiesis. There is increasing evidence that retinoids can significantly influence some of these changes. Retinoids may also have anticancer effects and protect against age-associated conditions such as macular degeneration. However, retinol (vitamin A) can be toxic when taken in excess and the elderly may be at particular risk for hypervitaminosis A. Evaluation of elderly people ingesting significantly more or less than the recommended daily intake of retinol requires an understanding of the biology of retinoids and consideration of the relative risks and benefits of supplementation.

Increasing referral of at-risk travelers to travel health clinics: evaluation of a health promotion intervention targeted to travel agents.

BACKGROUND: Increases in travel-related illness require new partnerships to ensure travelers are prepared for health risks abroad. The travel agent is one such partner and efforts to encourage travel agents to refer at-risk travelers to travel health clinics may help in reducing travel-attributable morbidity. METHODS: A health promotion intervention encouraging travel agents to refer at-risk travelers to travel health clinics was evaluated. Information on the knowledge, attitudes, and behaviors of travel agents before and after the intervention was compared using two self-administered questionnaires. The Wilcoxon signed rank test was used to compare the mean difference in overall scores to evaluate the overall impact of the intervention and also subscores for each of the behavioral construct groupings (attitudes, barriers, intent, and subjective norms). Multiple regression techniques were used to evaluate which travel agent characteristics were independently associated with a stronger effect of the intervention. RESULTS: A small improvement in travel agents overall attitudes and beliefs (p =.03) was found, in particular their intention to refer (p =.01). Sixty-five percent of travel agents self-reported an increase in referral behavior; owners or managers of the agency were significantly more likely to do so than other travel agents (OR = 7.25; 95% CI: 1.64 32.06). Older travel agents, those that worked longer hours and those with some past referral experience, had significantly higher post-intervention scores. CONCLUSIONS: Travel agents can be willing partners in referral, and agencies should be encouraged to develop specific referral policies. Future research may be directed toward investigating the role of health education in certification curricula, the effectiveness of different types of health promotion interventions, including Internet-facilitated interventions, and the direct impact that such interventions would have on travelers attending travel health clinics.

Intestinal amebiasis: a diagnosis not to be missed.

Entamoeba histolytica is a well-recognized cause of infectious colitis and disseminated amebic abscesses. Most prevalent in the tropics and subtropics, E. histolytica infections may also occur in the developed world. We describe a case of a North American traveler with intestinal amebiasis, a diagnosis first made by colonic biopsy. We review the available diagnostic tools and the role of the surgical pathologist in the detection of this infection.