Bi-national outbreak of Salmonella Newport infections linked to onions: the United States experience.

From 2016-2019, dry bulb onions were the suspected cause of three multistate outbreaks in the United States. We investigated a large multistate outbreak of Salmonella Newport infections that caused illnesses in both the United States and Canada in 2020. Epidemiologic, laboratory and traceback investigations were conducted to determine the source of the infections, and data were shared among U.S. and Canadian public health officials. We identified 1127 U.S. illnesses from 48 states with illness onset dates ranging from 19 June to 11 September 2020. Sixty-six per cent of ill people reported consuming red onions in the week before illness onset. Thirty-five illness sub-clusters were identified during the investigation and seventy-four per cent of sub-clusters served red onions to customers during the exposure period. Traceback for the source of onions in illness sub-clusters identified a common onion grower in Bakersfield, CA as the source of red onions, and onions were recalled at this time. Although other strains of Salmonella Newport were identified in environmental samples collected at the Bakersfield, CA grower, extensive environmental and product testing did not yield the outbreak strain. This was the third largest U.S. foodborne Salmonella outbreak in the last 30 years. It is the first U.S. multistate outbreak with a confirmed link to dry bulb onions, and it was nearly 10-fold larger than prior outbreaks with a suspected link to onions. This outbreak is notable for its size and scope, as well as the international data sharing that led to implication of red onions as the primary cause of the outbreak. Although an environmental assessment at the grower identified several factors that likely contributed to the outbreak, no main reason was identified. The expedient identification of the outbreak vehicle and response of multiple public health agencies allowed for recall and removal of product from the marketplace, and rapid messaging to both the public and industry on actions to protect consumers; these features contributed to a decrease in cases and expeditious conclusion of the outbreak.

Public health investigation and response to a hepatitis A outbreak from imported scallops consumed raw-Hawaii, 2016.

During the summer of 2016, the Hawaii Department of Health responded to the second-largest domestic foodborne hepatitis A virus (HAV) outbreak in the post-vaccine era. The epidemiological investigation included case finding and investigation, sequencing of RNA positive clinical specimens, product trace-back and virologic testing and sequencing of HAV RNA from the product. Additionally, an online survey open to all Hawaii residents was conducted to estimate baseline commercial food consumption. We identified 292 confirmed HAV cases, of whom 11 (4%) were possible secondary cases. Seventy-four (25%) were hospitalised and there were two deaths. Among all cases, 94% reported eating at Oahu or Kauai Island branches of Restaurant Chain A, with 86% of those cases reporting raw scallop consumption. In contrast, a food consumption survey conducted during the outbreak indicated 25% of Oahu residents patronised Restaurant Chain A in the 7 weeks before the survey. Product trace-back revealed a single distributor that supplied scallops imported from the Philippines to Restaurant Chain A. Recovery, amplification and sequence comparison of HAV recovered from scallops revealed viral sequences matching those from case-patients. Removal of product from implicated restaurants and vaccination of those potentially exposed led to the cessation of the outbreak. This outbreak further highlights the need for improved imported food safety.

Post-Campylobacter Guillain Barré Syndrome in the USA: secondary analysis of surveillance data collected during the 2009-2010 novel Influenza A (H1N1) vaccination campaign.

Guillain Barré syndrome (GBS), which is triggered by autoantibodies produced in response to antigenic stimuli such as certain infections and vaccinations, is the most common cause of acute flaccid paralysis worldwide. Campylobacter, the most common bacterial enteric infection in the USA, is reported to be the most commonly diagnosed antecedent of GBS, yet little information is available about the risk of post-Campylobacter GBS. Data collected through active, population-based surveillance in the Emerging Infections Program during the 2009-2010 novel Influenza A (H1N1) vaccination campaign allowed us to compare confirmed and probable GBS cases to non-cases to determine whether antecedent Campylobacter infection (or a diarrhoeal illness consistent with campylobacteriosis) was more common among cases and to assess the risk of GBS following Campylobacter infection. We estimate that 8-12% of GBS cases in the USA are attributable to Campylobacter infection (or a diarrhoeal illness consistent with campylobacteriosis), with 434-650 cases of post-diarrhoeal GBS annually and about 49 cases of GBS per 100 000 Campylobacter infections. These results provide updated estimates for post-Campylobacter GBS incidence in the USA and highlight an important benefit of effective measures to prevent Campylobacter infections.

Unusually high illness severity and short incubation periods in two foodborne outbreaks of Salmonella Heidelberg infections with potential coincident Staphylococcus aureus intoxication.

We describe the investigation of two temporally coincident illness clusters involving salmonella and Staphylococcus aureus in two states. Cases were defined as gastrointestinal illness following two meal events. Investigators interviewed ill persons. Stool, food and environmental samples underwent pathogen testing. Alabama: Eighty cases were identified. Median time from meal to illness was 5·8 h. Salmonella Heidelberg was identified from 27 of 28 stool specimens tested, and coagulase-positive S. aureus was isolated from three of 16 ill persons. Environmental investigation indicated that food handling deficiencies occurred. Colorado: Seven cases were identified. Median time from meal to illness was 4·5 h. Five persons were hospitalised, four of whom were admitted to the intensive care unit. Salmonella Heidelberg was identified in six of seven stool specimens and coagulase-positive S. aureus in three of six tested. No single food item was implicated in either outbreak. These two outbreaks were linked to infection with Salmonella Heidelberg, but additional factors, such as dual aetiology that included S. aureus or the dose of salmonella ingested may have contributed to the short incubation periods and high illness severity. The outbreaks underscore the importance of measures to prevent foodborne illness through appropriate washing, handling, preparation and storage of food.

Comparing Visual and Digital Counting Methods to Estimate Horn Fly (Diptera: Muscidae) Populations on Cattle.

Horn fly, Haematobia irritans (L.), population estimates often serve as a diagnostic tool prior to implementing managerial control options available to researchers and producers. Digital photographs taken of cattle infested with horn flies have been suggested to provide similarly accurate population estimates as compared with traditional visual assessments. The objective of this study was to compare visual and digital techniques used to estimate horn fly populations. Sixteen Angus × Hereford yearling heifers artificially infested with four levels of horn flies (Low = 0 flies; Medium = 250 flies; High = 500 flies; Extreme = 1,000 flies) were evaluated. Population estimates were taken visually by experienced (VE1) and inexperienced (VE2) technicians, as well as digitally, with photographs taken on both lateral sides of the south-facing animal. Horn flies were counted in both photographs and combined (CDC) for full body estimates. In addition, the highest photographed side population times two (DDC) was used for comparison. Estimations were made at 0700, 1200, and 1900 h the day following infestation. A time of observation × infestation level interaction (P < 0.01) was detected. On average, VE1 population estimates were greater (P < 0.01) than any other counting method observed. Morning estimates were greater (P < 0.05) than those taken at noon or in the early evening regardless of counting method. Further research regarding the standardization of these techniques to ensure more accurate population estimates is needed before these methods can be incorporated into integrated pest management programs.

International outbreak of multiple Salmonella serotype infections linked to sprouted chia seed powder - USA and Canada, 2013-2014.

Salmonella is a leading cause of bacterial foodborne illness. We report the collaborative investigative efforts of US and Canadian public health officials during the 2013-2014 international outbreak of multiple Salmonella serotype infections linked to sprouted chia seed powder. The investigation included open-ended interviews of ill persons, traceback, product testing, facility inspections, and trace forward. Ninety-four persons infected with outbreak strains from 16 states and four provinces were identified; 21% were hospitalized and none died. Fifty-four (96%) of 56 persons who consumed chia seed powder, reported 13 different brands that traced back to a single Canadian firm, distributed by four US and eight Canadian companies. Laboratory testing yielded outbreak strains from leftover and intact product. Contaminated product was recalled. Although chia seed powder is a novel outbreak vehicle, sprouted seeds are recognized as an important cause of foodborne illness; firms should follow available guidance to reduce the risk of bacterial contamination during sprouting.

2013 multistate outbreaks of Cyclospora cayetanensis infections associated with fresh produce: focus on the Texas investigations.

The 2013 multistate outbreaks contributed to the largest annual number of reported US cases of cyclosporiasis since 1997. In this paper we focus on investigations in Texas. We defined an outbreak-associated case as laboratory-confirmed cyclosporiasis in a person with illness onset between 1 June and 31 August 2013, with no history of international travel in the previous 14 days. Epidemiological, environmental, and traceback investigations were conducted. Of the 631 cases reported in the multistate outbreaks, Texas reported the greatest number of cases, 270 (43%). More than 70 clusters were identified in Texas, four of which were further investigated. One restaurant-associated cluster of 25 case-patients was selected for a case-control study. Consumption of cilantro was most strongly associated with illness on meal date-matched analysis (matched odds ratio 19·8, 95% confidence interval 4·0-∞). All case-patients in the other three clusters investigated also ate cilantro. Traceback investigations converged on three suppliers in Puebla, Mexico. Cilantro was the vehicle of infection in the four clusters investigated; the temporal association of these clusters with the large overall increase in cyclosporiasis cases in Texas suggests cilantro was the vehicle of infection for many other cases. However, the paucity of epidemiological and traceback information does not allow for a conclusive determination; moreover, molecular epidemiological tools for cyclosporiasis that could provide more definitive linkage between case clusters are needed.

Are psychiatrists only fools and horses to be open all hours?

The UK government's proposal for 24-hour healthcare means effectively asking doctors to work more unsociable hours for relatively little financial gain. In our opinion, psychiatry is particularly vulnerable to deterioration owing to negotiations of the terms of the current Consultant Contract that ensures fewer antisocial hours, whereas without parallel appropriate internal team and intra-agency working, provisions for which are not included in the government's proposals to extend care, patient care is vulnerable. Clarification and a narrower redefinition of what constitutes a psychiatric emergency is called for.

Ozonolysis of mixed oleic-acid/stearic-acid particles: reaction kinetics and chemical morphology.

The ozonolysis of mixed oleic-acid/stearic-acid (OL/SA) aerosol particles from 0/100 to 100/0 wt % composition is studied. The magnitude of the divergence of the particle beam inside an aerosol mass spectrometer shows that, in the concentration range 100/0 to 60/40, the mixed OL/SA particles are liquid prior to reaction. Upon ozonolysis, particles having compositions of 75/25 and 60/40 change shape, indicating that they have solidified during reaction. Transmission electron micrographs show that SA(s) forms needles. For particles having compositions of 75/25, 60/40, and greater SA content, the reaction kinetics exhibit an initial fast decay of OL for low O(3) exposure with no further loss of OL at higher O(3) exposures. For compositions from 50/50 to 10/90, the residual OL concentration remains at 28 +/- 2% of its initial value. The initial reactive uptake coefficient for O(3), as determined by OL loss, decreases linearly from 1.25 (+/-0.2) x 10(-3) to 0.60 (+/-0.15) x 10(-3) for composition changes of 100/0 to 60/40. At 50/50 composition, the uptake coefficient drops abruptly to 0.15 (+/-0.1) x 10(-3), and there are no further changes with increased SA content. These observations can be explained with a combination of three postulates: (1) Unreacted mixed particles remain as supersaturated liquids up to 60/40 composition, and the OL in this form rapidly reacts with O(3). (2) SA, as it solidifies, locks into its crystal structure a significant amount of OL, and this OL is completely inaccessible to O(3). (3) Accompanying crystallization, some stearic acid molecules connect as a filamentous network to form a semipermeable gel containing liquid OL but with a reduced uptake coefficient because of the decrease in molecular diffusivity in the gel. An individual particle of 50/50 to 90/10 is hypothesized as a combination of SA crystals having OL impurities (postulate 2) that are partially enveloped by an SA/OL gel (postulate 3) to explain (a) the abrupt drop in the uptake coefficient from 60/40 to 50/50 and (b) the residual OL content even after high ozone exposure. The results of this study, pointing out the important effects of particle phase, composition, and morphology on chemical reactivity, contribute to an improved understanding of the aging processes of atmospheric aerosol particles.

Ovine prostaglandin F2alpha receptor: steroid influence on steady-state levels of luteal mRNA.

Expression of the receptor for prostaglandin F2alpha (PGF2alpha) is decreased in the ovine corpus luteum during regression and increased in early pregnancy. This study was designed to evaluate the influence of progesterone and/or 17beta-estradiol (E2) on this regulation. Circulating progesterone (functional regression) and luteal PGF receptor mRNA decreased (p < 0.05) within 8 h of PGF2alpha-induced luteal regression in midluteal phase (day 10; d 10) ewes; however, internucleosomal DNA fragmentation (structural regression) was not yet increased. Additionally, luteal PGF receptor mRNA and circulating progesterone were greater (p < 0.05) in pregnant than in nonpregnant ewes on d 14, but not on d 12. Twelve hours following injection of d 10 ewes with E2, steady-state levels of mRNA for PGF receptor were decreased (p < 0.05), although circulating progesterone and DNA laddering were unchanged. Conversely, luteal mRNA for PGF receptor was increased (p < 0.05) by E2 treatment in hysterectomized ewes. These results provide evidence that (1) luteal PGF receptor expression parallels circulating progesterone levels during functional regression and in early pregnancy, but (2) expression of PGF receptor can be dissociated from alterations in circulating progesterone by injection with E2. Additionally, decreased PGF receptor expression initiated by E2 is uterine-dependent, whereas the direct luteal effect (hysterectomized ewes) of E2 is a stimulation of PGF receptor expression. These results collectively support the belief that the apparent downregulation of PGF receptor during luteal regression is associated with uterine-derived PGF2alpha and its intracellular effects rather than with alterations in ovarian steroid production.

Inhibition of hypothalamic GnRH secretion in the ewe by antigonadotropic decapeptide during the estrous cycle and nonbreeding season.

Previous experiments from our laboratory and others have shown that the peptide antigonadotropic decapeptide (AGD) has marked inhibitory effects on luteinizing hormone (LH) secretion in rats and ewes. The first objective of this study was to determine whether AGD inhibits LH secretion by regulating hypothalamic release of gonadotropin hormone (GnRH). AGD (200 microg in 200 microL of 0.3% bovine serum albumin [BSA] saline) or vehicle was infused into the lateral ventricle of ovariectomized (OVX) ewes with hypophyseal-portal cannulae, and GnRH secretion was monitored. The frequency of GnRH and LH pulses in AGD-treated ewes was significantly decreased (p < 0.05) but did not change in the control ewes. The second objective of this investigation was to evaluate changes in hypothalamic sensitivity to AGD in the ewe during the estrous cycle and nonbreeding season. During the estrous cycle, the effects of AGD on LH secretion were assessed following ovariectomy, during the metestrous, diestrous, and proestrous phases of the estrous cycle. The response to AGD during the estrous cycle was compared to its effect during the anestrous season. LH, cortisol, and prolactin (PRL) concentrations were assayed in peripheral blood samples obtained at 10-min intervals over a 6-h period prior to injection of either vehicle (200 microL of 0.3% BSA in 0.9% saline) or AGD (200 microg in 200 microL of vehicle), and for an additional 10 h following treatment. LH pulse frequency decreased after treatment with AGD (p < 0.05) at all times in OVX and intact ewes compared to vehicle-treated controls. During the anestrous season, AGD treatment was more effective in inhibiting LH pulse frequency than during the breeding season (p < 0.05). Furthermore, there was a significant increase (p < 0.05) in mean cortisol concentrations after AGD infusion in all AGD-treated groups compared to controls independent of season or reproductive status. PRL concentrations were also increased (p < 0.05) following treatment with AGD. These results suggest that inhibition of pulsatile LH release induced by AGD is modulated by alterations in frequency of hypothalamic discharges of GnRH. Furthermore, changes in the inhibitory actions of AGD may contribute to the seasonal regulation of hypothalamic GnRH secretion in the ewe.

Estradiol and gonadotropin-releasing hormone (GnRH) interact to increase GnRH receptor expression in ovariectomized ewes after hypothalamic-pituitary disconnection.

Gonadotropin-releasing hormone (GnRH) receptor expression is regulated by estradiol and GnRH itself. The objective of this experiment was to determine the extent to which low levels of estradiol, similar to those observed during the transition from the luteal to the follicular phase of the estrous cycle, and GnRH interact to regulate expression of GnRH receptors and GnRH receptor mRNA. Ewes were ovariectomized (OVX) at least 2 wk prior to initiation of the experiment, and the pituitary gland was surgically disconnected from the hypothalamus to remove ovarian and hypothalamic inputs to the pituitary. Within 24 h after hypothalamic-pituitary disconnection, ewes received pulses of GnRH (250 ng/pulse) every 2 h for 6 d. At the end of 6 d, ewes were randomly assigned to treatments in a 2 x 2 factorial arrangement as follows: half of the animals received a single estradiol implant and half received an empty implant (placebo). At the same time, animals also received one of the following treatments: (1) saline or (2) GnRH (100 ng/pulse/2 h). Additionally, one group of ewes was ovariectomized, but not subjected to hypothalamic-pituitary disconnection (OVX controls). Blood samples were collected 15 min prior to each pulse of GnRH or saline and at 15-min intervals for 1 h after each pulse until tissues were collected and concentrations of luteinizing hormone (LH) were determined. Anterior pituitaries were collected 24 h after implant insertion to quantitate steady-state amounts of GnRH receptor mRNA and numbers of GnRH receptors. Mean LH was greatest in ovariectomized control ewes compared to all other treatments (p < 0.05). Mean LH and LH pulse amplitude in the placebo and GnRH-treated group most closely mimicked LH secretion in ovariectomized control animals. Mean LH and LH pulse amplitude were similar between both GnRH-treated groups (p < 0.05). Mean LH and LH pulse amplitude were significantly lower in all animals treated with saline compared to OVX controls (p < 0.05). Treatment with an estradiol implant and pulsatile GnRH increased (p < 0.05) relative amounts of GnRH receptor mRNA and the number of GnRH receptors compared to all other treatments. There were no differences in GnRH receptor expression between the remaining treatment groups (p > 0.05). Therefore, in OVX ewes after hypothalamic-pituitary disconnection, low levels of estradiol and GnRH are required to increase GnRH receptor mRNA and GnRH receptor numbers. Since we only observed an increase in GnRH receptor expression in the presence of both estradiol and GnRH, we conclude that there is a synergistic interaction between these two hormones in the regulation of GnRH receptor expression.