Identifying Candidate Targets of Immune Responses in Zika Virus Based on Homology to Epitopes in Other Flavivirus Species

·

Introduction: The current outbreak of Zika virus has resulted in a massive effort to accelerate the development of ZIKV-specific diagnostics and vaccines. These efforts would benefit greatly from the definition of the specific epitope targets of immune responses in ZIKV, but given the relatively recent emergence of ZIKV as a pandemic threat, few such data are available.

Methods: We used a large body of epitope data for other Flaviviruses that was available from the IEDB for a comparative analysis against the ZIKV proteome in order to project targets of immune responses in ZIKV.

Results: We found a significant level of overlap between known antigenic sites from other Flavivirus proteins with residues on the ZIKV polyprotein. The E and NS1 proteins shared functional antibody epitope sites, whereas regions of T cell reactivity were conserved within NS3 and NS5 for ZIKV. 

Discussion: Our epitope based analysis provides guidance for which regions of the ZIKV polyprotein are most likely unique targets of ZIKV-specific antibodies, and which targets in ZIKV are most likely to be cross-reactive with other Flavivirus species. These data may therefore provide insights for the development of antibody- and T cell-based ZIKV-specific diagnostics, therapeutics and prophylaxis.

Pokémon Go and Exposure to Mosquito-Borne Diseases: How Not to Catch ‘Em All

·

Pokémon Go is a new game that encourages players to venture outdoors and interact with others in the pursuit of virtual Pokémon characters. With more time spent outdoors overall and in sometimes large congregations, Pokémon Go players could inadvertently elevate their risk of exposure to mosquito-borne diseases when playing in certain areas at certain times of year. Here, we make an initial assessment of the possible scope of this concern in the continental United States, which experiences its highest seasonal transmission of West Nile, Zika, and other viruses during summer and early fall. In particular, we propose that the times of day when many disease-relevant mosquito species are most likely to engage in blood feeding coincide with times of day when Pokémon Go activity is likely to be high, and we note that locations serving as hubs of Pokémon Go activity may in some cases overlap with areas where these mosquitoes are actively engaged in blood feeding. Although the risk of mosquito-borne diseases in the continental U.S. is low overall and is unlikely to be impacted significantly by Pokémon Go, it is nonetheless important for Pokémon Go players and others who spend time outdoors engaging in activities such as barbecues and gardening to be aware of these ongoing risks and to take appropriate preventative measures in light of the potential for outdoor activity to modify individual-level risk of exposure. As Pokémon Go and other augmented reality games become available in other parts of the world, similar risks should be assessed in a manner that is consistent with the local epidemiology of mosquito-borne diseases in those areas.

The Ebola Crisis and the Corresponding Public Behavior: A System Dynamics Approach

·

Background: The interaction of several sociocultural and environmental factors during an epidemic crisis leads to behavioral responses that consequently make the crisis control a complex problem.

Methods: The system dynamics approach has been adopted to study the relationships between spread of disease, public attention, situational awareness, and community’s response to the Ebola epidemic.

Results: In developing different simulation models to capture the trend of death and incidence data from the World Health Organization for the Ebola outbreak, the final model has the best fit to the historical trends. Results demonstrate that the increase of quarantining rate over time due to increase in situational awareness and performing safe burials had a significant impact on the control of epidemic. However, public attention did not play a significant role.

Conclusion: The best fit to historical data are achieved when behavioral factors specific to West Africa like studying the Situational Awareness and Public Attention are included in the model. However, by ignoring the sociocultural factors, the model is not able to represent the reality; therefore, in the case of any epidemics, it is necessary that all the parties and community members find the most significant behavioral factors that can curb the epidemic.

Series of Norovirus Outbreaks Caused by Consumption of Green Coral Lettuce, Denmark, April 2016

·

Introduction: In early April 2016, an unusual high number of point-source outbreaks of gastrointestinal disease were reported to occur in Denmark.

Methods: Outbreaks were individually investigated. Two analytical studies were performed. Patient stool samples collected and analysed; positive stool samples were sequenced over the polymerase and/or capsid gene areas. Implicated lettuce heads were collected and analysed for the presence of norovirus. Foods were traced-back and traced-forward and international alert systems applied.

Results: A total of 23 linked point-source outbreaks occurred over the course of one week. Fresh green coral lettuce (Lollo Bionda lettuce) had been consumed in all settings. In a cohort study including 234 participants a dish containing green lettuce was associated with illness. Norovirus of Genogroup I (GI) was detected in samples from 28 patients comprising eight of the outbreaks. Sequencing showed GI.P2-GI.2. GI norovirus was detected in one of 20 examined lettuce heads. All lettuce consumed was supplied by the same packer who in turn had bought the lettuce from a wholesaler in France. The two lots of lettuce came from two different growers in different parts of France.

Discussion: Green coral lettuce produced in France was found to have caused a large series of linked norovirus outbreaks in Denmark as established by a number of lines of evidence. A similar incidence occurred in 2010. Fresh lettuce increasingly appear to be a risk food for norovirus infections.

Experiences and Psychosocial Impact of West Africa Ebola Deployment on US Health Care Volunteers

·

Background: This qualitative study was designed to assess health care volunteers’ experiences and psychosocial impacts associated with deployment to the West Africa Ebola epidemic.

Methods: In 2015, using snowball sampling, 16 US health care volunteers who had recently returned from West Africa were recruited for this study. Semi-structured interviews were conducted to collect information associated with each phase of deployment (pre, peri, and post).

Results: Participants reported that they were motivated to volunteer because of a sense of responsibility and feelings of empathy and altruism. Immediately prior to deployment, most reported fear of contagion and death, as well as doubts regarding the adequacy of their training. Family members and close friends expressed high levels of concern regarding participants’ decisions to volunteer. During the deployment, participants were fearful of exposure and reported feeling emotionally and physically exhausted. They also reported feeling frustrated by extreme resource limitations, poor management of the mission, lack of clearly defined roles and responsibilities, and inability to provide high quality care. Upon return home, participants felt a sense of isolation, depression, stigmatization, interpersonal difficulties, and extreme stress.

Conclusion: Preparedness of volunteers was suboptimal at each stage of deployment. All stakeholders, including volunteers, sponsoring organizations, government agencies, and professional organizations have a shared responsibility in ensuring that volunteers to medical missions are adequately prepared. This is especially critical for high risk deployments. Effective policies and practices need to be developed and implemented in order to protect the health and well-being of health care volunteers to the fullest extent possible.

Isolation of Zika Virus Imported from Tonga into Australia

·

Introduction: The globally emergent Zika virus (ZIKV) is a threat to Australia, given the number of imported cases from epidemic regions and the presence of competent mosquito vectors. We report the isolation of ZIKV from a female traveler who recently returned from Tonga to Brisbane, Queensland, Australia in 2016.

Methods: A specific TaqMan real-time reverse transcriptase polymerase chain reaction assay (RT-PCR) assay was used to detect ZIKV in serum and urine samples. Conventional cell culture techniques and suckling mice were employed in an attempt to isolate ZIKV from serum and urine.

Results: A ZIKV isolate (TS17-2016) was recovered from the serum sample after one passage in suckling mouse brains and harvested 11 days post inoculation. Phylogenetic analysis of complete envelope (E) gene sequences demonstrated TS17-2016 shared 99.9% nucleotide identity with other contemporary sequences from Tonga 2016, Brazil 2015 and French Polynesia 2013 within the Asian lineage.

Discussion: This is the first known report of successful isolation of ZIKV from a human clinical sample in Australia and the first from a traveler from Tonga. This study highlights the potential difficulties in isolating ZIKV from acute clinical samples using conventional cell culture techniques, particularly in non-endemic countries like Australia where access to samples of sufficient viral load is limited. The successful isolation of TS17-2016 will be essential for continued investigations of ZIKV transmission and pathogenicity and will enable the advancement of new preventative control measures extremely relevant to the Australian and Pacific region.

Lessons from Ebola: Sources of Outbreak Information and the Associated Impact on UC Irvine and Ohio University College Students

·

Objectives. We examined the role of outbreak information sources through four domains: knowledge, attitudes, beliefs, and stigma related to the 2014 Ebola virus disease (EVD) outbreak.

Methods. We conducted an online survey of 797 undergraduates at the University of California, Irvine (UCI) and Ohio University (OU) during the peak of the outbreak. We calculated individual scores for domains and analyzed associations to demographic variables and news sources.

Results. Knowledge of EVD was low and misinformation was prevalent. News media (34%) and social media (19%) were the most used sources of EVD information while official government websites (OGW) were among the least used (11%). Students who acquired information through OGW had higher knowledge, more positive attitudes towards those infected, a higher belief in the government, and were less likely to stigmatize Ebola victims.

Conclusions. Information sources are likely to influence students’ knowledge, attitudes, beliefs, and stigma relating to EVD. This study contains crucial insight for those tasked with risk communication to college students. Emphasis should be given to developing effective strategies to achieve a comprehensive knowledge of EVD and future public health threats.

Invasion Dynamics of Teratogenic Infections in Light of Rubella Control: Implications for Zika Virus

·

Introduction: The greatest burden for a subset of pathogens is associated with infection during pregnancy. Evidence for teratogenic effects of Zika Virus have highlighted the importance of understanding the epidemiology of such pathogens. Rubella is perhaps the most classic example, and there is much to be learned from the long history of modelling associated with this virus.

Methods: We extended an existing framework for modeling age-specific dynamics of rubella to illustrate how the body of knowledge of rubella dynamics informs the dynamics of teratogenic infections more broadly, and particularly the impact of control on such infections in different transmission settings.

Results: During invasion, the burden in women of childbearing age is expected to peak, but then fall to low levels before eventually levelling out. Importantly, as illustrated by rubella dynamics, there is potential for a paradoxical effect, where inadequate control efforts can increase the burden.

Conclusions: Drawing on the existing body of work on rubella dynamics highlights key knowledge gaps for understanding the risks associated with Zika Virus. The magnitude and impacts of sterilizing immunity, plus antigenic maps measuring cross-protection with other flaviviruses, and the magnitude of transmission, as well as likely impact of control efforts on transmission are likely to be key variables for robust inference into the outcome of management efforts for Zika Virus.

Genetic Studies of Vibrio cholerae in South West Cameroon—A Phylogenetic Analysis of Isolates from the 2010-2011 Epidemic

·

Introduction: During the cholera outbreak from 2010 to 2011 in Cameroon, 33,192 cases with 1,440 deaths (case fatality ratio 4.34%) were reported to the World Health Organization. Of these, the South West Region reported 3,120 clinical cases. This region is in the Equatorial Monsoon climatic subzone of Cameroon, close to the coast, raising questions as to whether cases were linked with development of environmental reservoirs.

Methods: In an investigation conducted by the Laboratory for Emerging Infectious Diseases, University of Buea, toxigenic V. cholerae O1 were isolated from diarrheal stool samples from 18 patients, with ages ranging from <3 to 70 years. Coordinates for clinical centers at which cases were identified were obtained using a handheld GPS, and were mapped using ArcGIS. Antibiotic susceptibility testing was performed using the Kirby ‘Bauer agar disc diffusion method. The full genomes of these strains were sequenced with the Illumina MiSeq platform. De novo assembly of cholera genomes and multiple sequence alignment were carried out using the bioinformatics pipeline developed in the Emerging Pathogens Institute laboratory at the University of Florida.

Results/Discussion: Genetic comparisons showed that isolates were closely related, with pairwise p-distances ranging from 2.25 to 14.52 10-5 nt substitutions per site, and no statistically significant correlation between the pairwise genetic distances and the geographic distances among sampling locations. Indeed, the phylogeny of the Cameroonian strains displays the typical star-like topology and intermixing of strains from different locations that are characteristic of an exponential outbreak localized around a relatively restricted area with occasional spillover to other parts of the country, likely mediated by direct human contact and human movement. Findings highlight the utility of whole genome sequencing and phylogenetic analysis in understanding transmission patterns at the local level.

Taste and Safety: Is the Exceptional Cuisine Offered by High End Restaurants Paralleled by High Standards of Food Safety?

·

Introduction: Restaurant guides such as the Good Food Guide Top 50 create a hierarchy focussing on taste and sophistication. Safety is not explicitly included. We used restaurant associated outbreaks to assess evidence for safety.

Methods: All foodborne disease outbreaks in England reported to the national database from 2000 to 2014 were used to compare the Top 50 restaurants (2015) to other registered food businesses using the Public Health England (PHE) outbreak database. Health Protection Teams were also contacted to identify any outbreaks not reported to the national database. Among Good Food Guide Top 50 restaurants, regression analysis estimated the association between outbreak occurrence and position on the list.

Results: Four outbreaks were reported to the PHE national outbreak database among the Top 50 giving a rate 39 times higher (95% CI 14.5–103.2) than other registered food businesses. Eight outbreaks among the 44 English restaurants in the Top 50 were identified by direct contact with local Health Protection Teams. For every ten places higher ranked, Top 50 restaurants were 66% more likely to have an outbreak (Odds Ratio 1.66, 95% CI 0.89–3.13).

Discussion: Top 50 restaurants were substantially more likely to have had reported outbreaks from 2000-2014 than other food premises, and there was a trend for higher rating position to be associated with higher probability of reported outbreaks. Our findings, that eating at some of these restaurants may pose an increased risk to health compared to other dining out, raises the question of whether food guides should consider aspects of food safety alongside the clearly important complementary focus on taste and other aspects of the dining experience.