The association between sporadic Legionnaires' disease and weather and environmental factors, Minnesota, 2011-2018.

From 2011 through 2018, there was a notable increase in sporadic Legionnaires' disease in the state of Minnesota. Sporadic cases are those not associated with a documented outbreak. Outbreak-related cases are typically associated with a common identified contaminated water system; sporadic cases typically do not have a common source that has been identified. Because of this, it is hypothesised that weather and environmental factors can be used as predictors of sporadic Legionnaires' disease. An ecological design was used with case report surveillance data from the state of Minnesota during 2011 through 2018. Over this 8-year period, there were 374 confirmed Legionnaires' disease cases included in the analysis. Precipitation, temperature and relative humidity (RH) data were collected from weather stations across the state. A Poisson regression analysis examined the risk of Legionnaires' disease associated with precipitation, temperature, RH, land-use and age. A lagged average 14-day precipitation had the strongest association with Legionnaires' disease (RR 2.5, CI 2.1-2.9), when accounting for temperature, RH, land-use and age. Temperature, RH and land-use also had statistically significant associations to Legionnaires' disease, but with smaller risk ratios. This study adds to the body of evidence that weather and environmental factors play an important role in the risk of sporadic Legionnaires' disease. This is an area that can be used to target additional research and prevention strategies.

Understanding Spatio-Temporal Variability in the Reproduction Ratio of the Bluetongue (BTV-1) Epidemic in Southern Spain (Andalusia) in 2007 Using Epidemic Trees.

Andalusia (Southern Spain) is considered one of the main routes of introduction of bluetongue virus (BTV) into Europe, evidenced by a devastating epidemic caused by BTV-1 in 2007. Understanding the pattern and the drivers of BTV-1 spread in Andalusia is critical for effective detection and control of future epidemics. A long-standing metric for quantifying the behaviour of infectious diseases is the case-reproduction ratio (Rt), defined as the average number of secondary cases arising from a single infected case at time t (for t>0). Here we apply a method using epidemic trees to estimate the between-herd case reproduction ratio directly from epidemic data allowing the spatial and temporal variability in transmission to be described. We then relate this variability to predictors describing the hosts, vectors and the environment to better understand why the epidemic spread more quickly in some regions or periods. The Rt value for the BTV-1 epidemic in Andalusia peaked in July at 4.6, at the start of the epidemic, then decreased to 2.2 by August, dropped below 1 by September (0.8), and by October it had decreased to 0.02. BTV spread was the consequence of both local transmission within established disease foci and BTV expansion to distant new areas (i.e. new foci), which resulted in a high variability in BTV transmission, not only among different areas, but particularly through time, which suggests that general control measures applied at broad spatial scales are unlikely to be effective. This high variability through time was probably due to the impact of temperature on BTV transmission, as evidenced by a reduction in the value of Rt by 0.0041 for every unit increase (day) in the extrinsic incubation period (EIP), which is itself directly dependent on temperature. Moreover, within the range of values at which BTV-1 transmission occurred in Andalusia (20.6°C to 29.5°C) there was a positive correlation between temperature and Rt values, although the relationship was not linear, probably as a result of the complex relationship between temperature and the different parameters affecting BTV transmission. Rt values for BTV-1 in Andalusia fell below the threshold of 1 when temperatures dropped below 21°C, a much higher threshold than that reported in other BTV outbreaks, such as the BTV-8 epidemic in Northern Europe. This divergence may be explained by differences in the adaptation to temperature of the main vectors of the BTV-1 epidemic in Andalusia (Culicoides imicola) compared those of the BTV-8 epidemic in Northern Europe (Culicoides obsoletus). Importantly, we found that BTV transmission (Rt value) increased significantly in areas with higher densities of sheep. Our analysis also established that control of BTV-1 in Andalusia was complicated by the simultaneous establishment of several distant foci at the start of the epidemic, which may have been caused by several independent introductions of infected vectors from the North of Africa. We discuss the implications of these findings for BTV surveillance and control in this region of Europe.

Quantifying the Risk of Introduction of West Nile Virus into Great Britain by Migrating Passerine Birds.

West Nile virus (WNV) is a mosquito borne arbovirus that circulates within avian reservoirs. WNV can spill over into humans and Equidae that are dead-end hosts for WNV but suffer fever, acute morbidity and sometimes death. Outbreaks of WNV are common across Africa and Eastern Europe, and there have also been sporadic outbreaks in Spain and the Camargue Regional Park in France, but never in Great Britain (GB). These areas all fall along a major bird migration route. In this study, we analyse a scenario in which WNV is circulating in the Camargue or in other wetland areas in France and we estimate the risk of northward migrating passerine birds stopping in a WNV hotspot, becoming infected and carrying active infection to GB. If the disease were circulating in the Camargue during a single migratory season, the probability that one or more migrating birds becomes infected and lands in GB whilst still infected is 0.881 with 0.384 birds arriving in areas of suitable vector habitat. However, if WNV became established in the Grand Brière National Park or La Brenne Regional Park wetland areas further to the north, the model predicts that at least one infected bird will continue to GB. Thus, GB is at risk of WNV introduction from the Camargue, but the risk is considerably greater if WNV were to circulate further north than its previous focus in France, but this is highly sensitive to the force of infection in the infected area. However, the risk of establishment and infection of humans in GB is dependent upon a number of additional factors, in particular the vector and epidemiological situation in GB.

Identifying environmental drivers of insect phenology across space and time: Culicoides in Scotland as a case study.

Interpreting spatial patterns in the abundance of species over time is a fundamental cornerstone of ecological research. For many species, this type of analysis is hampered by datasets that contain a large proportion of zeros, and data that are overdispersed and spatially autocorrelated. This is particularly true for insects, for which abundance data can fluctuate from zero to many thousands in the space of weeks. Increasingly, an understanding of the ways in which environmental variation drives spatial and temporal patterns in the distribution, abundance and phenology of insects is required for management of pests and vector-borne diseases. In this study, we combine the use of smoothing techniques and generalised linear mixed models to relate environmental drivers to key phenological patterns of two species of biting midges, Culicoides pulicaris and C. impunctatus, of which C. pulicaris has been implicated in transmission of bluetongue in Europe. In so doing, we demonstrate analytical tools for linking the phenology of species with key environmental drivers, despite using a relatively small dataset containing overdispersed and zero-inflated data. We demonstrate the importance of landcover and climatic variables in determining the seasonal abundance of these two vector species, and highlight the need for more empirical data on the effects of temperature and precipitation on the life history traits of palearctic Culicoides spp. in Europe.

Haploinsufficiency of RanBP2 is neuroprotective against light-elicited and age-dependent degeneration of photoreceptor neurons.

Prolonged light exposure is a determinant factor in inducing neurodegeneration of photoreceptors by apoptosis. Yet, the molecular bases of the pathways and components triggering this cell death event are elusive. Here, we reveal a prominent age-dependent increase in the susceptibility of photoreceptor neurons to undergo apoptosis under light in a mouse model. This is accompanied by light-induced subcellular changes of photoreceptors, such as dilation of the disks at the tip of the outer segments, prominent vesiculation of nascent disks, and autophagy of mitochondria into large multilamellar bodies. Notably, haploinsufficiency of Ran-binding protein-2 (RanBP2) suppresses apoptosis and most facets of membrane dysgenesis observed with age upon light-elicited stress. RanBP2 haploinsufficiency promotes decreased levels of free fatty acids in the retina independent of light exposure and turns the mice refractory to weight gain on a high-fat diet, whereas light promotes an increase in hydrogen peroxide regardless of the genotype. These studies demonstrate the presence of age-dependent and RanBP2-mediated pathways modulating membrane biogenesis of the outer segments and light-elicited neurodegeneration of photoreceptors. Furthermore, the findings support a mechanism whereby the RanBP2-dependent production of free fatty acids, metabolites thereof or the modulation of a cofactor dependent on any of these, promote apoptosis of photoreceptors in concert with the light-stimulated production of reactive oxygen species.

A prospective, randomized, parallel group, controlled study of the effect of intensity of speech and language therapy on early recovery from poststroke aphasia.

OBJECTIVE: To examine whether the amount of speech and language therapy influences the recovery from poststroke aphasia. SETTING: A hospital stroke unit and community. DESIGN: A prospective, randomized controlled trial. INTERVENTION: Aphasic stroke patients were randomly allocated to receive 5 hours (intensive therapy group, n=51) or 2 hours (standard therapy group) of speech and language therapy per week for 12 consecutive weeks starting as soon as practicable after the stroke. Another 19 patients were recruited for 2 hours per week of therapy and were treated by National Health Service (NHS) staff (NHS group). OUTCOME MEASURE AND ASSESSMENT: The Western Aphasia Battery. Assessments were made blind to randomization at baseline and 4, 8, 12 and 24 weeks after the start of therapy. Data were analysed by intention to treat. RESULTS: The mean (SD) Western Aphasia Battery score at week 12 for the intensive, standard and NHS groups was 70.3 (26.9), 66.2 (26.2) and 58.1 (33.7), respectively. There was no treatment effect of intensive therapy (P > 0.05), but there was a statistically significant difference between the standard study and the NHS groups (P = 0.002 at week 12 and 0.01 at week 24). CONCLUSIONS: Intensive speech and language therapy (as delivered in this study) did not improve the language impairment significantly more than the ;standard' therapy which averaged 1.6 hours/week. The improvement in aphasia was least in patients who were in the NHS group. These patients received 0.57 (0.49) hours of therapy per week.

The role of inflammation in preterm birth--focus on periodontitis.

It is universally accepted that acute inflammation is responsible for a substantial fraction of preterm births, particularly early cases. Much of this inflammation is caused by intrauterine infection. There is also evidence that infection and perhaps inflammation remote from the genitourinary tract can trigger preterm labour. Several studies have suggested that periodontitis during pregnancy increases the risk of preterm birth. Periodontitis may cause preterm birth by causing low-grade bacteraemia, which lodges in the decidua, chorion and amnion or by releasing endotoxin into the maternal circulation, which triggers intrauterine inflammation and preterm birth. Alternatively, it may release cytokines and other inflammatory products, which then trigger preterm labour. It is also conceivable that periodontitis might serve as a marker for other unhealthy behaviours, or immune hyperresponsiveness and that hyperresponsiveness to low-grade intrauterine infection itself might cause preterm birth. Currently, there are few data available to distinguish these possibilities. Such distinctions are important since they have clear implications for whether treatment of periodontitis might reduce the incidence of preterm birth. Several clinical trials of treatment of periodontitis are continuing, but until their results are known there is currently little evidence that treatment of periodontitis during pregnancy reduces the incidence of preterm birth.

High scores on the Western Aphasia Battery correlate with good functional communication skills (as measured with the Communicative Effectiveness Index) in aphasic stroke patients.

OBJECTIVE: To examine the correlation between an impairment-level and a functional-level assessment scale of aphasia. DESIGN: Prospective, longitudinal study. SETTING: A stroke rehabilitation unit. SUBJECTS: Sixty-seven aphasic acute stroke patients who were undergoing a multi-disciplinary rehabilitation programme, including conventional speech and language therapy (SLT). INTERVENTION: Patients were assessed on study entry and 4, 8, 12 and 24 weeks after the start of SLT. The language impairment was assessed with the Western Aphasia Battery (WAB) and the communicative functional limitation associated with aphasia was measured with the Communicative Effectiveness Index (CETI).Results. There was a statistically significant correlation between the two scales for all assessment periods (Pearson's r=0.71; P<0.01). CONCLUSION: The study suggests that in the acute and subacute stages of stroke the scores of WAB and CETI can be surmised from one another.

Electrical stimulation of transforming growth factor-beta 1 secretion by human dermal fibroblasts and the U937 human monocytic cell line.

The in vitro effects on human dermal fibroblasts and the U937 human monocytic cell line of three phases of electrical microcurrents generated by the ACE Stimulator were investigated. The growth and viability of growing and confluent dermal fibroblasts were not directly influenced by the separate microcurrent phases. One form of microcurrent (designated phase 1) stimulated both dermal fibroblasts and U937 cells to secrete transforming growth factor-beta 1 (TGF-beta 1), which is an important regulator of cell-mediated inflammation and tissue regeneration, but none of the three phases stimulated secretion of the pro-inflammatory cytokine interleukin-6 by U937 cells. The stimulation of TGF-beta 1 secretion in these experiments was not dramatic (a median increase over control levels of 20-30%), although it could be biologically significant.

Seroprevalence of parvovirus B19 NS1-specific IgG in B19-infected and uninfected individuals and in infected pregnant women.

Parvovirus B19 is the causative agent of erythema infectiosum in children, but the virus is associated with an increasing range of different diseases. These include acute and chronic arthritis, hydrops fetalis in pregnant women, aplastic anemia, and thrombocytopenia. The host's immune response is directed against the viral structural proteins VP1 and VP2. This study investigated the presence of IgG against the viral nonstructural protein NS1 using Western blot. Serum panels from healthy individuals, B19-infected pregnant women, and various disease groups were tested. The disease groups included patients with symptoms that may be linked to parvovirus B19 infection. The results showed that IgG against the NS1 protein was present in 22% of healthy individuals with past B19 infection. In cases of persistent or prolonged B19 infections, the prevalence of NS1-specific antibodies was as high as 80%. It is concluded that NS1-specific IgG may be used as an indicator of chronic or more severe courses of parvovirus B19 infections.

Development of antibodies to the nonstructural protein NS1 of parvovirus B19 during acute symptomatic and subclinical infection in pregnancy: implications for pathogenesis doubtful.

At present little is known about the mechanisms influencing the course and severity of parvovirus B19 infection. Antibodies to the parvovirus nonstructural protein NS1 were reported in patients with parvovirus-associated arthritis and those with persisting infection but not in those without complications, suggesting a potential involvement of NS1 or anti-NS1 antibodies in pathogenesis. The immune response to NS1 was examined retrospectively in 33 pregnant women with acute parvovirus B19 infection, 14 of whom experienced symptomatic infection and 19 in whom the infection was subclinical. Antibodies to NS1 were found in 15 (45%) of the women, seven with symptomatic and eight with subclinical infection. No association was found between the development of anti-NS1 antibodies and the occurrence of fetal complications. Of the seven cases in which fetal complications were observed, anti-NS1 antibodies were detected in only three. The finding that an immune response to NS1 can also be demonstrated in patients with asymptomatic infection suggests that anti-NS1 antibodies do not appear to represent a marker for an altered or severe course of infection in pregnant women or to contribute significantly to pathogenesis. Since anti-NS1 antibodies first become detectable at least six weeks postinfection, their presence can be used to exclude acute infection in patients with unclear serology or be used to aid differential diagnosis of rashlike illnesses.

Acute parvovirus B19 infection in pregnant women--an analysis of serial samples by serological and semi-quantitative PCR techniques.

The serological and virological course of parvovirus B19 infection was followed in 14 women who suffered symptomatic or subclinical acute infection during pregnancy. Serial serum samples from the patients were tested for IgG and IgM antibodies and the levels of parvovirus B19 DNA were monitored using a semi-quantitative PCR assay. In addition, the outcome of the pregnancies was documented by clinical information and by testing cord blood for parvovirus B19 specific antibodies as well as for parvovirus B19 DNA by PCR. Levels of IgG antibodies rose steadily within 2 months of infection and in some cases began to decline at the end of pregnancy. IgM antibodies were usually detected for at least 2 months and persisted for as long as 9 months in one case. Viral DNA was detectable for at least 8 weeks following infection and semi-quantitative analysis revealed a gradual reduction in virus load during the viraemic phase of infection. There were no apparent differences in the course of antibody development and duration of viraemia in symptomatic versus subclinical infections.

Life-threatening parvovirus B19-associated myocarditis and cardiac transplantation as possible therapy: two case reports.

Parvovirus B19 infection can cause a wide spectrum of disease syndromes. Two cases of parvovirus B19 infection were identified that resulted in life-threatening myocarditis shortly after acute infection in immunocompetent individuals. The diagnosis was made with serological and polymerase chain reaction techniques. One patient was successfully treated by heart transplantation. Sequence analysis showed that the parvovirus B19 cloned from the patients' sera had 99% homology with the prototype sequence. Clinicians should be alerted to the possible role of parvovirus B19 in myocarditis presenting in immunocompetent patients.

Maternal serum alpha-fetoprotein and human chorionic gonadotropin in pregnant women with acute parvovirus B19 infection with and without fetal complications.

Maternal serum alpha-fetoprotein (MS-AFP) and human gonadotropin (MS-hCG) were retrospectively determined in 137 sera from 65 pregnant women with an acute parvovirus B19 infection. In 35 of the pregnant women, fetal complications occurred (group 1); in the remaining 30 women, there were no fetal complications (group 2). In group I, significant elevations of MS-AFP were detected in 13 of the 35 women (37 per cent) and of MS-hCG in 25 of the 35 women (71 per cent). In nine of those women, sera were obtained before occurrence of fetal complications and MS-AFP was elevated in one case and MS-hCG in four cases. In one woman, both MS-AFP and MS-hCG were elevated. In group 2, significant elevations of MS-AFP were found in two of the 30 women (6-7 per cent) and of MS-hCG in five of the 30 women (16.7 per cent). Neither MS-AFP nor MS-hCG appears to be a regular early marker for poor pregnancy outcome in parvovirus B19-infected pregnancies, although they were frequently elevated at the time of complications.

Parvovirus B19 diagnosis in pregnant women--quantification of IgG antibody levels (IU/ml) with reference to the international parvovirus B19 standard serum.

On the basis of the results of a collaborative study the Expert Committee on Biological Standardisation of the World Health Organisation has issued an international standard (IS) serum for parvovirus B19 IgG antibody (NIBSC 93/724). In this study this IS was used to calibrate an in-house standard serum for reporting the results of parvovirus B19 IgG testing in IU/ml. The IgG titre distribution in 939 pregnant women was determined. These samples were sent to the laboratory for determining the immune status to parvovirus B19 following contact with parvovirus B19 infected individuals or for detecting acute infection in patients with symptoms suggestive of parvovirus B19 infection.

Violence and remote area nursing.

The Federal government and others have accepted that violence is a problem in rural and remote communities across Australia. The issue of personal safety for Remote Area Nurses (RANs) living in remote areas has been mentioned in a number of State and Regional reports. However, to the knowledge of this research group, no systematic attempt to gather data on the incidence of violence experienced by RANs and other remote health workers has occurred. This study aims to redress the lack of data on the experience and description of violence against remote area nurses. Results indicate that remote area nurses are living with frequent threats to their personal safety while on duty, on call and off duty, and that violent incidents are often handled badly by employers, the community and remote area nurses themselves. Twenty-four-hour call is an employment requirement for 82% of respondents. Those required to be on call 24 hours experience episodes of violence more frequently. Despite nearly all of the respondents experiencing episodes of violence within the 12 months prior to the study, there was a tendency for remote area nurses, except in the case of physical violence, to perceive both the frequency and the severity of their experiences with violence as low and not personally directed.

A successful laboratory outreach program.

Many economists say the recession is ending--if not over already. Those of us in health care are still facing trying times, and health-care reform may be just around the corner. Many hospitals are developing or enhancing laboratory outreach programs to ease their financial burdens. In the first of a two-part "As We See It," CLMR spoke with expert laboratorians who discuss the need for an outreach program and who should be involved in its development, as well as how hospital laboratories can establish the proper business culture to run a successful program. We asked: How do you develop and operate a successful laboratory outreach program?