As of 13 July 2016, 13 countries have reported fetal Zika virus (ZIKV) infection. Here we report a case of fetal ZIKV infection that resulted from an infection originating in Vietnam.
Introduction: Uganda has reported eight outbreaks caused by filoviruses between 2000 to 2016, more than any other country in the world. We used species distribution modeling to predict where filovirus outbreaks are likely to occur in Uganda to help in epidemic preparedness and surveillance.
Methods: The MaxEnt software, a machine learning modeling approach that uses presence-only data was used to establish filovirus – environmental relationships. Presence-only data for filovirus outbreaks were collected from the field and online sources. Environmental covariates from Africlim that have been downscaled to a nominal resolution of 1km x 1km were used. The final model gave the relative probability of the presence of filoviruses in the study area obtained from an average of 100 bootstrap runs. Model evaluation was carried out using Receiver Operating Characteristic (ROC) plots. Maps were created using ArcGIS 10.3 mapping software.
Results: We showed that bats as potential reservoirs of filoviruses are distributed all over Uganda. Potential outbreak areas for Ebola and Marburg virus disease were predicted in West, Southwest and Central parts of Uganda, which corresponds to bat distribution and previous filovirus outbreaks areas. Additionally, the models predicted the Eastern Uganda region and other areas that have not reported outbreaks before to be potential outbreak hotspots. Rainfall variables were the most important in influencing model prediction compared to temperature variables.
Conclusions: Despite the limitations in the prediction model due to lack of adequate sample records for outbreaks, especially for the Marburg cases, the models provided risk maps to the Uganda surveillance system on filovirus outbreaks. The risk maps will aid in identifying areas to focus the filovirus surveillance for early detection and responses hence curtailing a pandemic. The results from this study also confirm previous findings that suggest that filoviruses are mainly limited by the amount of rainfall received in an area.
Background: A multi-provincial outbreak of Salmonella enterica serovar Enteritidis was linked to newly hatched chicks and poults from a single hatchery during the spring of 2015. In total, there were 61 human cases that were epidemiologically confirmed to be linked to the chicks and poults and the outbreak was deemed to have ended in the summer of 2015.
Methods: PulseNet Canada, in coordination with the affected provinces, used genome sequencing of human and agricultural Salmonella Enteritidis isolates to aid in the epidemiological investigation, while also using traditional typing methods such as phagetyping and pulsed-field gel electrophoresis (PFGE).
Results: All human outbreak cases, except one, were Phage Type (PT) 13a. Single nucleotide variant analysis (SNV) was able to provide a level of resolution commensurate with the results of the epidemiological investigation. SNV analysis was also able to separate PT13a outbreak-related isolates from isolates not linked to chicks or poults, while clustering some non-PT13a agricultural strains with the outbreak cluster.
Conclusions: Based on conventional typing methods (phagetyping or PFGE), clinical and agricultural PT13a SE isolates would have been considered as part of a related cluster. In contrast, phagetyping would have led to the exclusion of several non- PT13a strains that clustered with the outbreak isolates using the genome sequence data. This study demonstrates the improved resolution of genome sequence analysis for coordinated surveillance and source attribution of both human and agricultural SE isolates.
Introduction: Infrequent natural human inhalational anthrax cases coupled with high bioterrorism risk have brought about use of animal models to serve as the basis for approval of novel treatments. For inhalational anthrax, protective antigen (PA) drives much of the mortality, and raxibacumab, an anti-PA monoclonal antibody, has been approved for therapeutic use using the Animal Rule. Given the paucity of human inhalational anthrax clinical data including PA kinetics, the post-exposure period for effective treatment of human disease remains unknown. The objective of this investigation was to extrapolate animal PA kinetics to a conceptual human model to estimate the post-exposure period for effective treatment of human inhalational anthrax.
Methods: Human PA kinetic parameters were extrapolated from reported rabbit and monkey data. PA profiles were simulated with and without antibiotic induced PA clearance to represent antibiotic-sensitive and -resistant infections, respectively. Antitoxin levels equimolar to or greater than concurrent PA levels were considered protective.
Results: For antibiotic sensitive infections, treatment with antibiotics alone ≤4 days after spore exposure prevents toxemia. Administration of raxibacumab together with antibiotics protects ≥ 80% of subjects for 3 additional days (7 days post exposure). In the setting of antibiotic resistance, raxibacumab would be protective for at least 6 days post exposure.
Conclusions: Although the animal model of disease does not reflect the potential impact of supportive care (e.g. fluid resuscitation received by critically ill patients) on PA kinetics and raxibacumab PK, the simulations suggest that administration of antitoxin in combination with antibiotics should provide a longer postexposure window for effective treatment than for antibiotics alone. In addition, raxibacumab administration soon after exposure to an antibiotic resistant strain should provide effective treatment.
Listeria monocytogenes (Lm) is a bacterium widely distributed in nature and able to contaminate food processing environments, including those of dairy products. Lm is a primary public health issue, due to the very low infectious dose and the ability to produce severe outcomes, in particular in elderly, newborns, pregnant women and immunocompromised patients.
In the period between April and July 2015, an increased number of cases of listeriosis was observed in the area of Pavia, Northern Italy. An epidemiological investigation identified a cheesemaking small organic farm as the possible origin of the outbreak. In this work we present the results of the retrospective epidemiological study that we performed using molecular biology and genomic epidemiology methods. The strains sampled from patients and those from the target farm’s cheese were analyzed using PFGE and whole genome sequencing (WGS) based methods. The performed WGS based analyses included: a) in-silico MLST typing; b) SNPs calling and genetic distance evaluation; c) determination of the resistance and virulence genes profiles; d) SNPs based phylogenetic reconstruction.
Three of the patient strains and all the cheese strains resulted to belong to the same phylogenetic cluster, in Sequence Type 29. A further accurate SNPs analysis revealed that two of the three patient strains and all the cheese strains were highly similar (0.8 SNPs of average distance) and exhibited a higer distance from the third patient isolate (9.4 SNPs of average distance).
Despite the global agreement among the results of the PFGE and WGS epidemiological studies, the latter approach agree with epidemiological data in indicating that one the patient strains could have originated from a different source. This result highlights that WGS methods can allow to better
Introduction: Predicting the timing and locations of future mosquito-borne disease outbreaks has the potential to improve the targeting of mosquito control and disease prevention efforts. Here, we present and evaluate prospective forecasts made prior to and during the 2016 West Nile virus (WNV) season in South Dakota, a hotspot for human WNV transmission in the United States.
Methods: We used a county-level logistic regression model to predict the weekly probability of human WNV case occurrence as a function of temperature, precipitation, and an index of mosquito infection status. The model was specified and fitted using historical data from 2004-2015 and was applied in 2016 to make short-term forecasts of human WNV cases in the upcoming week as well as whole-year forecasts of WNV cases throughout the entire transmission season. These predictions were evaluated at the end of the 2016 WNV season by comparing them with spatial and temporal patterns of the human cases that occurred.
Results: There was an outbreak of WNV in 2016, with a total of 167 human cases compared to only 40 in 2015. Model results were generally accurate, with an AUC of 0.856 for short-term predictions. Early-season temperature data were sufficient to predict an earlier-than-normal start to the WNV season and an above-average number of cases, but underestimated the overall case burden. Model predictions improved throughout the season as more mosquito infection data were obtained, and by the end of July the model provided a close estimate of the overall magnitude of the outbreak.
Conclusions: An integrated model that included meteorological variables as well as a mosquito infection index as predictor variables accurately predicted the resurgence of WNV in South Dakota in 2016. Key areas for future research include refining the model to improve predictive skill and developing strategies to link forecasts with specific mosquito control and disease prevention activities.
Background: Subtype H5N1 avian influenza viruses, both high pathogenicity and low pathogenicity, have been enzootic in Vietnam since 2001. The viruses are readily identified at live bird markets, but virus prevalence on smallholder poultry is typically zero or very low. If the true direction of the viral transmission chain is farm to market, it is unknown why farm prevalence should be low when market prevalence is moderate to high.
Methods: We established a cohort of 50 smallholder poultry farms in Ca Mau province in the Mekong Delta region of Vietnam. From March 2016 to January 2017, we collected naso-pharyngeal and cloacal samples from 156 ducks and 96 chickens. In addition, 126 environmental samples were collected. Samples were assayed for H5 subtype influenza by real-time RT-PCR.
Results/Discussion: None of the 378 collected samples were positive for H5 influenza. This is likely to mean that circulation of subtype H5 influenza viruses was low in Ca Mau in 2016. Detection of avian influenza on smallholder poultry farms is necessary to determine the directionality and association between farm prevalence and market prevalence of avian influenza viruses. Larger farm-level studies should be planned as these will be critical for determining the presence and strength of this association.
Introduction: We report the results of a rapid assessment of Zika virus awareness among key clinical specialties in Singapore.
Methods: Between June 6 and June 19, 2016 we conducted an online survey of doctors working in obstetrics and gynaecology, neonatology and paediatrics in Singapore. The survey included 15 multiple choice questions to measure respondents’ knowledge of Zika virus in four domains covering clinical and public health.
Results: A total of 110 survey responses (15% response rate) were obtained, 82% of respondents worked in the public sector. Overall, the median respondent score was 9.4 (Max score=15), with substantial variation (range: 3.5 – 14.7). Microcephaly and Guillain-Barré syndrome were recognised as causal complications of Zika virus infection by 99% and 50% of respondents respectively. Clinical features which could help differentiate Zika from Dengue were less well understood with 50% and 68% correctly identifying conjunctivitis and low grade fever respectively. Worryingly, 14% favoured non-steroidal anti-inflammatory drugs as part of treatment, without first excluding dengue as a diagnosis. Also, only 36% of respondents were aware of the current recommendation for preventing sexual transmission of Zika virus. Fewer than 50% were aware of the need for ophthalmological evaluation as part of congenital Zika virus infection.
Discussion: Our assessment demonstrates that there is good awareness of the clinical manifestation of Zika virus disease among key specialty doctors, but confusion with Dengue disease remains. It also highlights knowledge gaps in the prevention of sexually-transmitted Zika virus infection and the clinical management of congenital Zika virus infection in newborns. Our study identified strategic areas to improve communication to front-line doctors during public health response to the Zika epidemic.
Introduction: Although many studies have investigated the probability of Ebola virus disease (EVD) outbreaks while other studies have simulated the size and speed of EVD outbreaks, few have investigated the environmental and population-level predictors of Ebola transmission once an outbreak is underway. Identifying strong predictors of transmission could help guide and target limited public health resources during an EVD outbreak. We examined several environmental and population-level demographic predictors of EVD risk from the West African epidemic. Methods: We obtained district-level estimates from the World Health Organization EVD case data, demographic indicators obtained from the Demographic and Health surveys, and satellite-derived temperature, rainfall, and land cover estimates. A Bayesian hierarchical Poisson model was used to estimate EVD risk and to evaluate the spatial variability explained by the selected predictors. Results: We found that districts had greater risk of EVD with increasing proportion of households not possessing a radio (RR 2.79, 0.90-8.78; RR 4.23, 1.16-15.93), increasing rainfall (RR 2.18; 0.66-7.20; 5.34, 1.20-23.90), and urban land cover (RR 4.87, 1.56-15.40; RR 5.74, 1.68-19.67). Discussion: The finding of radio ownership and reduced EVD transmission risk suggests that the use of radio messaging for control and prevention purposes may have been crucial in reducing the EVD transmission risk in certain districts, although this association requires further study. Future research should examine the etiologic relationships between the identified risk factors and human-to-human transmission of EVD with a focus on factors related to population mobility and healthcare accessibility, which are critical features of epidemic propagation and control.
Introduction: This paper reports the findings of a national online survey to parents of children aged 5 and younger. The objectives of the study were to assess parental understanding of childhood immunizations, identify sources of information that they trust for vaccine-related content, assess where parents with young children stand on the key issues in the public debate about vaccination, and identify which risk communication messages are most effective for influencing the behaviours of vaccine hesitant parents.
Methods: A total of 1,000 surveys (closed and open-ended questions) were administered in November 2015 using the Angus Reid Forum Panel, a key consumer panel consisting of approximately 150,000 Canadian adults aged 18 and older, spread across all geographic regions of Canada.
Results: Approximately 92% of the Canadian parents surveyed consider vaccines safe and effective, and trust doctors and public health officials to provide timely and credible vaccine-related information. However, a concerning number of them either believe or are uncertain whether there is a link between vaccines and autism (28%), worry that vaccines might seriously harm their children (27%), or believe the pharmaceutical industry is behind the push for mandatory immunization (33%). Moreover, despite the common assumption that social media are becoming the go-to source of health news and information, most parents still rely on traditional media and official government websites for timely and credible information about vaccines and vaccine preventable diseases, particularly during community-based disease outbreaks. Finally, parents reported high levels of support for pro-vaccine messaging that has been demonstrated in previous research to have little to no positive impact on behaviour change, and may even be counterproductive.
Discussion: The study’s results are highly relevant in a context where public health officials are expending significant resources to increase rates of childhood immunization and combat vaccine hesitancy. The data offer insight into where parents stand on the political and public debate about mandatory vaccination, what aspects of vaccine science remain uncertain to them, which media and institutional sources they use and trust to navigate the health information environment, how they look for information and whom they trust during periods of health emergency or crisis, and which communication strategies are considered most effective in persuading vaccine hesitant parents to immunize their children.