Retrospective Analysis Of Surveillance Data Research Articles

Epidemiology of tuberculosis in Saudi Arabia following the implementation of end tuberculosis strategy: Analysis of the surveillance data 2015-2019.

To analyze the evolution of tuberculosis (TB) epidemiology in Saudi Arabia in the 5 years following the implementation of the end-TB Strategy. A retrospective analysis of surveillance data, reported by the national tuberculosis control program from 2015-2019, was carried out. The annual incidence and the percentage of yearly changes were calculated and compared to the World Health Organization (WHO) milestones, which anticipate a 4-5% annual decline. Additionally, various other epidemiological indicators of TB were examined. The national TB incidence declined from 10.55% per 100,000 in 2015 to 8.76% per 100,000 in 2019, aligning with the WHO's 2019 milestone estimated between 8.59-8.96% per 100,000. While Makkah Region (40.3%) and Riyadh (24.6%) accounted for the majority of cases, Jazan region consistently exhibited the highest incidence throughout the study period. Demographic features shifted towards a younger age category, male, and native dominance. There was a consistent decrease in resistance and intermediate sensitivity to all first-line anti-TB drugs, associated with a substantial decrease in both polydrug resistance (from 4.7-1.9%; p<0.001) and multidrug resistance (from 4.4-2.4%; p=0.008). The figures of TB incidence TB in Saudi Arabia between 2015-2019 has met the WHO end-TB milestones, predicting successful progress toward the 2035 goal.

Transmission dynamics, responses, and clinical features for the first 1100 COVID-19 cases in South Batinah, Oman: Major lessons from a provincial perspective

ObjectivesThis study was aimed at exploring and analyzing the epidemiological profile, surveillance, and response to COVID-19, including transmission dynamics and cluster formation. MethodologyThis was a retrospective analysis of surveillance data, including contact tracing, risk factors, and clinical information. Binary logistic regressions were used to assess the likelihood of admission, cluster formation, and of each individual being an index patient. Clusters were demonstrated through geographic data systems, network analysis, and visualization software. ResultsA total of 1100 COVID-19 cases were diagnosed from 20 March to 7 June 2020, of which 144 (13.1%) were asymptomatic. The median time from symptom onset to admission was 7 days (IQR, 4.5–10), and the median symptom duration was 5 days (IQR, 3–9). Eighty-nine clusters containing 736 patients were identified. The surveillance and control actions were divided into three phases. Clusters began to form in phase 2 and became more pronounced in phase 3. Patients ≥50 years of age and patients presenting with fever had relatively higher odds of admission: OR = 12.85 (95% CI 5.13–32.19) and 2.53 (95% CI 1.24–5.17), respectively. Cluster formation was observed among females, asymptomatic patients, and people living in Awabi: OR = 2.3 (95% CI 1.7–3.1), 6.39 (95% CI 2.33–17.2), and 3.54 (95% CI 2.06–6.07), respectively. Patients working in the police and defense sectors had higher odds of being an index patient: OR = 7.88 (95% CI 3.35–18.52). ConclusionCase-based interventions should be supported by population-wide measures, particularly movement restrictions. Establishing prevention teams or district units, or primary care will be crucial for the control of future pandemics. Prevention should always be prioritized for vulnerable populations.

Feeding practices of children within institution-based care: A retrospective analysis of surveillance data.

There is limited information on the feeding practices of 9.42 million children living within institution‐based care (IBC) worldwide. Poor feeding practices can predispose or exacerbate malnutrition, illness and disability. Here we describe the feeding practices of children living within IBC based on a retrospective analysis of records from 3335 children, 0–18 years old, participating in Holt International's Child Nutrition Program (CNP), from 36 sites in six countries. Data analysed included demographic information on age, sex, feeding practices, disabilities and feeding difficulties. Descriptive statistics were produced. A generalised linear model explored associations between feeding difficulties and disability and 2 × 2 tables examined feeding difficulties over time. An additional set of feeding observations with qualitative and quantitative data was analysed. At baseline, the median age of children was 16 months (0.66–68 months) with 1650/3335 (49.5%) females. There were 757/3335 (22.7%) children with disabilities; 550/984 (55.9%) were low birth weight; 311/784 (39.7%) were premature; 447/3113 (14.4%) had low body mass index and 378/3335 (11.3%) had feeding difficulties. The adjusted risk of having a feeding difficulty was 5.08 ([95% confidence interval: 2.65–9.7], p ≤ 0.001) times greater in children with disabilities than those without. Many children saw their feeding difficulties resolve after 1‐year in CNP, 54/163 (33.1%) for children with disabilities and 57/106 (53.8%) for those without disabilities. Suboptimal hygiene, dietary and feeding practices were reported. In conclusion, feeding difficulties were common in IBC, especially among children with disabilities. Supporting safe interactive mealtimes for children living within IBC should be prioritised, to ensure overall health and development.

Characterization of Unlinked Cases of COVID-19 and Implications for Contact Tracing Measures: Retrospective Analysis of Surveillance Data.

BackgroundContact tracing and intensive testing programs are essential for controlling the spread of COVID-19. However, conventional contact tracing is resource intensive and may not result in the tracing of all cases due to recall bias and cases not knowing the identity of some close contacts. Few studies have reported the epidemiological features of cases not identified by contact tracing (“unlinked cases”) or described their potential roles in seeding community outbreaks.ObjectiveFor this study, we characterized the role of unlinked cases in the epidemic by comparing their epidemiological profile with the linked cases; we also estimated their transmission potential across different settings.MethodsWe obtained rapid surveillance data from the government, which contained the line listing of COVID-19 confirmed cases during the first three waves in Hong Kong. We compared the demographics, history of chronic illnesses, epidemiological characteristics, clinical characteristics, and outcomes of linked and unlinked cases. Transmission potentials in different settings were assessed by fitting a negative binomial distribution to the observed offspring distribution.ResultsTime interval from illness onset to hospital admission was longer among unlinked cases than linked cases (median 5.00 days versus 3.78 days; P<.001), with a higher proportion of cases whose condition was critical or serious (13.0% versus 8.2%; P<.001). The proportion of unlinked cases was associated with an increase in the weekly number of local cases (P=.049). Cluster transmissions from the unlinked cases were most frequently identified in household settings, followed by eateries and workplaces, with the estimated probability of cluster transmissions being around 0.4 for households and 0.1-0.3 for the latter two settings.ConclusionsThe unlinked cases were positively associated with time to hospital admission, severity of infection, and epidemic size—implying a need to design and implement digital tracing methods to complement current conventional testing and tracing. To minimize the risk of cluster transmissions from unlinked cases, digital tracing approaches should be effectively applied in high-risk socioeconomic settings, and risk assessments should be conducted to review and adjust the policies.

Risk factors for the spread of vaccine-derived type 2 polioviruses after global withdrawal of trivalent oral poliovirus vaccine and the effects of outbreak responses with monovalent vaccine: a retrospective analysis of surveillance data for 51 countries in Africa

SummaryBackgroundExpanding outbreaks of circulating vaccine-derived type 2 poliovirus (cVDPV2) across Africa after the global withdrawal of trivalent oral poliovirus vaccine (OPV) in 2016 are delaying global polio eradication. We aimed to assess the effect of outbreak response campaigns with monovalent type 2 OPV (mOPV2) and the addition of inactivated poliovirus vaccine (IPV) to routine immunisation.MethodsWe used vaccination history data from children under 5 years old with non-polio acute flaccid paralysis from a routine surveillance database (the Polio Information System) and setting-specific OPV immunogenicity data from the literature to estimate OPV-induced and IPV-induced population immunity against type 2 poliomyelitis between Jan 1, 2015, and June 30, 2020, for 51 countries in Africa. We investigated risk factors for reported cVDPV2 poliomyelitis including population immunity, outbreak response activities, and correlates of poliovirus transmission using logistic regression. We used the model to estimate cVDPV2 risk for each 6-month period between Jan 1, 2016, and June 30, 2020, with different numbers of mOPV2 campaigns and compared the timing and location of actual mOPV2 campaigns and the number of mOPV2 campaigns required to reduce cVDPV2 risk to low levels.FindingsType 2 OPV immunity among children under 5 years declined from a median of 87% (IQR 81–93) in January–June, 2016 to 14% (9–37) in January–June, 2020. Type 2 immunity from IPV among children under 5 years increased from 3% (<1–6%) in January–June, 2016 to 35% (24–47) in January–June, 2020. The probability of cVDPV2 poliomyelitis among children under 5 years was negatively correlated with OPV-induced and IPV-induced immunity and mOPV2 campaigns (adjusted odds ratio: OPV 0·68 [95% CrI 0·60−0·76], IPV 0·82 [0·68−0·99] per 10% absolute increase in estimated population immunity, mOPV2 0·30 [0·20−0·44] per campaign). Vaccination campaigns in response to cVDPV2 outbreaks have been smaller and slower than our model shows would be necessary to reduce risk to low levels, covering only 11% of children under 5 years who are predicted to be at risk within 6 months and only 56% within 12 months.InterpretationOur findings suggest that as mucosal immunity declines, larger or faster responses with vaccination campaigns using type 2-containing OPV will be required to stop cVDPV2 transmission. IPV-induced immunity also has an important role in reducing the burden of cVDPV2 poliomyelitis in Africa.FundingBill & Melinda Gates Foundation, Medical Research Council Centre for Global Infectious Disease Analysis, and WHO.TranslationFor the French translation of the abstract see Supplementary Materials section.

Tick-borne encephalitis (TBE) in Switzerland: does the prolongation of vaccine booster intervals result in an increased risk of breakthroughs?

In 2006, the Swiss Federal Office of Public Health (FOPH) decided recommending a prolongation of vaccine booster intervals after the third dose for the prevention of tick-borne encephalitis (TBE) from 3 to 10years. To ascertain whether this amendment resulted in an increased rate of vaccine breakthroughs, we conducted a retrospective analysis of surveillance data collected 2000-19 by mandatory reporting to the Swiss FOPH. Fractions of breakthroughs [with 95% confidence intervals (CIs)]-0-3years vs >3-10years after the third vaccination dose-were compared across time periods and age groups. Among 3205 notified TBE cases, known vaccination status was reported in 2562 (79.9%), including 103 patients with ≥3 vaccine doses (4.0%). Among those, there were 39 patients who had received the last dose within 3years and 48 patients in the >3-10years group. During the 2010-19 period in which the new booster strategy was implemented there were 23 and 38 breakthroughs, respectively, and the annual breakthrough rate was 7.7 (95% CI 5.0-11.7) cases during the first 3years after the last dose, and 5.4 (95% CI 3.9-7.5) cases in following 7years. We observed no significant trend of TBE breakthroughs with increasing age. Increasing numbers of TBE and of vaccine breakthroughs over time have been associated with spreading endemicity and higher vaccination coverage in Switzerland. There is no indication that extended booster intervals resulted in an increased rate of breakthroughs, but there was a marked public health benefit with respect to increased acceptability of TBE immunization in the general population.

The changing epidemiology of hemorrhagic fever with renal syndrome in Southeastern China during 1963-2020: A retrospective analysis of surveillance data.

Hemorrhagic fever with renal syndrome (HFRS) is a rodent-borne disease caused by hantavirus which was endemic Zhejiang Province, China. In this study, we aim to explore the changing epidemiology of HFRS in Zhejiang, identify high-risk areas and populations, and evaluate relevant policies and interventions to better improve HFRS control and prevention. Surveillance data on HFRS during 1963-2020 in Zhejiang Province were extracted from Zhejiang Provincial Center for Disease Control and Prevention archives and the Chinese Notifiable Disease Reporting System. The changing epidemiological characteristics of HFRS including seasonal distribution, geographical distribution, and demographic features, were analyzed using joinpoint regression, autoregressive integrated moving average model, descriptive statistical methods, and Spatio-temporal cluster analysis. From 1963 to 2020, 114 071 HFRS cases and 1269 deaths were reported in Zhejiang Province. The incidence increased sharply from 1973 and peaked in 1986, then decreased steadily and maintained a stable incidence from 2004. HFRS cases were reported in all 11 prefecture-level cities of Zhejiang Province from 1963 to 2020. The joint region (Shengzhou, Xinchang, Tiantai, and surrounding areas), and Kaihua County are the most seriously affected regions throughout time. After 1990, the first HFRS incidence peak was in May-June, with another one from November to January. Most HFRS cases occurred in 21- (26.48%) and 30- years group (24.25%) from 1991 to 2004, but 41- (25.75%) and 51-years (23.30%) had the highest proportion from 2005 to 2020. Farmers accounted for most cases (78.10%), and cases are predominantly males with a male-to-female ratio of 2.6:1. It was found that the median time from onset to diagnosis was 6.5 days (IQR 3.75-10.42), and the time from diagnosis to disease report was significantly shortened after 2011. We observed dynamic changes in the seasonal distribution, geographical distribution, and demographic features of HFRS, which should be well considered in the development of control and prevention strategies in future. Additional researches are warranted to elucidate the environmental, meteorological, and social factors associated with HFRS incidence in different decades.

Regional differences in COVID-19 attack and case fatality rates in the first quarter of 2020: a comparative study

Background and Objective: The COVID-19 (Coronavirus disease 2019) outbreak has become a public health threat all over the world. From December 31, 2019 to March 19, 2020, 146 countries were affected. Evidence on the management approaches of current COVID-19 pandemic is still limited though the numbers of affected countries are increasing as the days go by. This study was aimed at determining the attack rate (AR) and case fatality rate (CFR) of Covid-19 in six different regions around the world in the first quarter of 2020. An attempt was also made to provide an overview of the ongoing situation of COVID-19.&#x0D; Methods: The design of the study was mixed approach where a retrospective analysis of surveillance data of six different regions around the world were collected from COVID-19 dashboard of World Health organization, between 31 December 2019 to 19 March 2020 (Time: 2:00 pm. BST [CET: 9 am]). Besides, other different validated sources (example: Worldometer, Center for Disease Control and Prevention) were used to assess the ongoing situation regarding COVID-19. A statistical software SPSS version 26 was used to analyze the data.&#x0D; Results: There were a total of 207,860 confirmed cases and 8779 deaths across six different regions around the world from 31 December 2019 to 19 March 2020, with the highest AR of 9.92/100,000 population in Europe region, followed by Asia (2.7/ 100,000), Australia (1.75/100,000), North America (1.42/100,000), South America (0.23/100,000) and Africa (0.06/100,000) regions. Study results revealed statistically significant association between attack rates and the six regions of the world (p=0.002), meaning that AR varied in the regions around the world. The CFR was high in Europe region (4.81%), followed by Asia (4.06%), Africa (2.72%), South America (1.41%), Australia (1.12%), and North America (0.69%) regions. Data reviewed from different countries revealed that the highest number of cases was confirmed in the United States, followed by Spain and Italy. The findings revealed that the reported confirmed cases varied widely in different regions of the world.&#x0D; Conclusion: The severity and variation in -geographical distribution of COVID-19 cases and deaths suggest that urgent response from various government and public health authorities should be taken and research regarding underlying factors determining this severity should be sought for.&#x0D; Ibrahim Med. Coll. J. 2020; 14(2): 1-10

Geographical and socioeconomic disparities in opioid access in Mexico, 2015–19: a retrospective analysis of surveillance data

SummaryBackgroundIn 2015, Mexico implemented regulatory changes and an electronic system to improve access to prescription opioids. We aimed to investigate trends in opioid dispensing after the implementation of these changes and assess how opioid dispensing varied geographically and by socioeconomic status.MethodsIn this retrospective analysis of prescription medication surveillance data, we analysed dispensing data for group 1 medications (all opioids, including morphine, methadone, hydromorphone, oxycodone, tapentadol, fentanyl, sufentanil, and remifentanil) obtained from the Federal Commission for the Protection against Sanitary Risk database for 32 states and six large metropolitan areas in Mexico. We calculated crude annual opioid prescriptions per 10 000 people at the national, state, and municipal levels. Adapting methods from the report of the Lancet Commission on Palliative Care and Pain Relief, we calculated the need for palliative opioids by state, and then assessed the observed opioid dispensing rates as a percentage of expected need by geographical socioeconomic status. Within the six major metropolitan areas, we mapped the geocoded location of opioid prescriptions and assessed the association between opioid dispensing and socioeconomic status as well as the association between opioid dispensing and time to US border crossing for areas on the US–Mexico border.FindingsBetween June 25, 2015, and Oct 7, 2019, opioid dispensing rates increased by an average of 13% (95% CI 6·8–19·6) per quarter (3 months). The overall national opioid dispensing rate during the study period was 26·3 prescriptions per 10 000 inhabitants. States with a higher socioeconomic status had higher opioid dispensing rates than states with lower socioeconomic status (rate ratio [RR] 1·88, 95% CI 1·33–2·58, p=0·00016) after controlling for the estimated opioid requirement per state, the presence of methadone clinics, and the presence of tertiary hospitals and cancer centres. The same association between opioid dispensing and socioeconomic status was observed in the metropolitan areas, and in those metropolitan areas on the US–Mexico border a 20% decrease (RR 0·80, 95% CI 0·75–0·86) in opioid dispensation was observed per each SD increase (SD 17·1 min) in travel time to the border.InterpretationMeasures introduced by the Mexican federal Government to increase opioid access for patients with palliative care needs were only marginally successful in raising opioid prescription rates. Opioid access should be improved for patients with palliative care needs who live in geographical areas of lower socioeconomic status.FundingUS National Institutes of Health.

Epidemiology of measles in a security compromised setting: A retrospective analysis of surveillance data in Borno State Nigeria, 2007–2017

Epidemiology of measles in a security compromised setting: A retrospective analysis of surveillance data in Borno State Nigeria, 2007–2017

Spatial analysis of chronic wasting disease in free‐ranging white‐tailed deer ( Odocoileus virginianus ) in Illinois, 2008–2019

Understanding the geographic distribution and clustering of chronic wasting disease (CWD) among free-ranging white-tailed deer (Odocoileus virginianus) populations can inform disease management practices. We used a retrospective analysis of surveillance data to evaluate CWD's spatial and temporal dynamics within 16 CWD-infected northern Illinois counties. Of 42,541 deer samples collected and tested for CWD from recreational hunter harvest between 2008 and 2019, we recorded 359 (0.84%) CWD-positive samples. We observed variability in CWD cases over time and space. By county, the median CWD-positive proportion was 0.84%, varying from a minimum of 0.14% in McHenry County to a maximum of 6.28% in Boone County. Across years, there were differences among CWD-positive proportions with a median of 0.90%, ranging from a minimum of 0.27% in 2012 to a maximum of 1.60% in 2019. We used a retrospective discrete Poisson scan statistic model to evaluate the space-time clustering of CWD-positive deer. We identified a statistically significant (p<.001) primary cluster C1 (area=23.59km2 ; RR=10.48), occurring from 2010 to 2015 in the north-central part of the study area, and a secondary cluster C2, occurring from 2014 to 2019 (area=9.27km2 ; RR=3.88) in the north-west of the study area. Detected CWD-positive space-time clusters suggest that the risk of CWD is not random. Space-time clusters of CWD can be used to evaluate the effectiveness of the Illinois CWD management programme. The area surrounding the older C1 cluster has undergone longer and more intense CWD management compared with C2. Currently, the older C1 cluster is no longer as high risk compared with the newer cluster C2, suggesting that management efforts in C2 should be increased. However, all CWD clusters should be targeted with surveillance, prevention and management programmes, including reducing deer densities to limit further spread of CWD.

Reflecting on tuberculosis case notification and treatment outcomes in the Volta region of Ghana: a retrospective pool analysis of a multicentre cohort from 2013 to 2017

BackgroundTuberculosis (TB) remains a petrified condition with a huge economic and health impact on families and health systems in Ghana. Monitoring of TB programme performance indicators can provide reliable data for direct measurement of TB incidence and mortality. This study reflects on the trends of TB case notification and treatment outcomes and makes comparison among 10 districts of the Volta region of Ghana.MethodsThis was a retrospective analysis of surveillance data of a cohort of TB cases from 2013 to 2017. Trends of case notification and treatment outcomes were examined and compared. Logistic regression was used to determine the independent relationship between patients and disease characteristics and unsuccessful treatment outcomes. Odds ratios, 95% confidence intervals and p-values were estimated.ResultsA gradual declining trend of case notification of all forms of TB was noticed, with an overall case notification rate (CNR) of 65 cases per 100,000 population during the period. A wide variation of case notification of TB was observed among the districts, ranging from 32 to 124 cases per 100,000 population. Similarly, treatment success rate decreased slightly from 83.1% during the first year to 80.2% in 2017, with an overall treatment success rate of 82.5% (95% CI: 81.3–83.8%). Treatment failure, death, and lost to follow up rates were 0.8% (range 0.5–1.2%), 13.5% (range 12.4–14.7%), and 3.1% (range 2.6–3.8%) respectively. The treatment success rate among districts ranged from 70.5% in South Tongu to 90.8% in Krachi West district. Returned after treatment interruption (Adjusted odds ratio [AOR]: 3.62; 95% CI: 1.66–7.91; P < 0.001) and TB/HIV co-infection (AOR: 1.94; 95% CI: 1.57–2.40; P < 0.001) predicts poor treatment outcomes.ConclusionOver the past five years, TB case notification and successful treatment outcomes did not significantly improve. Wide district variations in CNR was observed. The overall treatment success rate observed in this study is below the target of > 90% set by the World Health Organization’s (WHO) end TB strategy. Additionally, patients who returned to continue treatment after interruption and those who were co-infected with HIV strongly predict unsuccessful treatment outcomes. Sustained interventions to prevent treatment interruptions and improved management of co-morbidities can enhance treatment outcomes, as required to achieve the elimination goal.

Descriptive epidemiology of cholera outbreak in Nigeria, January\u2013November, 2018: implications for the global roadmap strategy

BackgroundThe cholera outbreak in 2018 in Nigeria reaffirms its public health threat to the country. Evidence on the current epidemiology of cholera required for the design and implementation of appropriate interventions towards attaining the global roadmap strategic goals for cholera elimination however seems lacking. Thus, this study aimed at addressing this gap by describing the epidemiology of the 2018 cholera outbreak in Nigeria.MethodsThis was a retrospective analysis of surveillance data collected between January 1st and November 19th, 2018. A cholera case was defined as an individual aged 2 years or older presenting with acute watery diarrhoea and severe dehydration or dying from acute watery diarrhoea. Descriptive analyses were performed and presented with respect to person, time and place using appropriate statistics.ResultsThere were 43,996 cholera cases and 836 cholera deaths across 20 states in Nigeria during the outbreak period, with an attack rate (AR) of 127.43/100,000 population and a case fatality rate (CFR) of 1.90%. Individuals aged 15 years or older (47.76%) were the most affected age group, but the proportion of affected males and females was about the same (49.00 and 51.00% respectively). The outbreak was characterised by four distinct epidemic waves, with higher number of deaths recorded in the third and fourth waves. States from the north-west and north-east regions of the country recorded the highest ARs while those from the north-central recorded the highest CFRs.ConclusionThe severity and wide-geographical distribution of cholera cases and deaths during the 2018 outbreak are indicative of an elevated burden, which was more notable in the northern region of the country. Overall, the findings reaffirm the strategic role of a multi-sectoral approach in the design and implementation of public health interventions aimed at preventing and controlling cholera in Nigeria.

An evaluation of the electronic reporting system for the enhanced surveillance of carbapenemase-producing Gram-negative bacteria in England

An electronic reporting system (ERS) for the enhanced surveillance of carbapenemase-producing Gram-negative bacteria (CPGNB) was launched by Public Health England in May 2015. This evaluation aimed to assess uptake, timeliness and completeness of data provided and explore potential barriers and facilitators to adopting the system. The evaluation comprised a retrospective analysis of surveillance data and semi-structured interviews with ERS users. The proportion of organisms referred for investigation of carbapenem resistance via ERS increased over the first 12 months post-implementation from 35% to 73%; uptake varied widely across regions of England. Completeness of enhanced data fields was poor in 78% of submitted isolates. The median number of days to report confirmatory test results via ERS was 1 day for the regional service and nine days for the national reference laboratory, which additionally conducts phenotypic testing to confirm carbapenemase negativity. Hindrances to ERS utility included: a lack of designated, ongoing resource for system maintenance, technical support and development; uncertainty about how and when to use ERS and workload. Incomplete data prevented gaining a better understanding of important risk factors and transmission routes of CPGNB in England. The ERS is the only surveillance system in England with the potential to gather intelligence on important risk factors for CPGNB to inform public health measures to control their spread. Although the ERS captures more information on CPGNB than other surveillance systems, timeliness and completeness of the enhanced data require substantial improvements in order to deliver the desired health benefits.

Predicting the climatic risk of myrtle rust during its first year in New Zealand

After the first detection of myrtle rust (Austropuccinia psidii) on mainland New Zealand in May 2017, the Ministry for Primary Industries sought information about how weather conditions would affect regional and seasonal risk of disease establishment to help plan the incursion response. Using internationally published information, a pathogen-process model was developed to predict infection, latent period and sporulation in relation to weather variables (temperature, relative humidity and solar radiation). This Myrtle Rust Process Model (MRPM) was implemented by the National Institute of Water and Atmospheric Research Limited using numerical weather model data to produce weekly maps of potential risk. Predicted risk was greatest in northern North Island and decreased further south, but was still substantial in coastal areas of the north-western South Island during summer and autumn. Risk was low in southern coastal areas of the South Island and the lowest risk occurred in mountainous areas, particularly in the South Island. Retrospective analysis of surveillance data showed that the MRPM accurately predicted geographic risk and it is currently in use for tactical planning of incursion surveillance and organism management.&#x0D;

Temporal trends in Giardia occurrence in the Grand River and surrounding tributaries, Waterloo, Ontario (2005-2013), a retrospective analysis of surveillance data.

Giardia contamination in the Grand River Watershed (south-western Ontario, Canada) was monitored from 2005 to 2013 as part of FoodNet Canada. Our study objectives were to describe the temporal pattern of Giardia occurrence and determine whether water quality parameters and bacterial indicators could act as effective markers for Giardia occurrence. Water samples were collected monthly from the Grand River near a drinking water intake point (2005-2013) and also collected intermittently from other areas in the watershed during the study period. Samples were tested for Giardia cysts using the US EPA method 1623. Samples were also tested for chemical and microbial water quality indicators. Univariable and multivariable linear regression models were built to examine whether temporal, water quality and bacterial indicators were associated with Giardia cyst concentration. Giardia cysts were identified in 89% of samples (n=228), with highest measured concentrations downstream of a waste water treatment plant outfall. Year and season were found to be predictors for Giardia occurrence. Concentrations were significantly higher in the winter and fall compared to the summer, and significantly higher in 2007 compared to other study years. After controlling for season, year and sampling location, dissolved oxygen was the only variable significantly associated with Giardia cyst concentration. Seasonal peaks in Giardia cyst concentrations in samples collected near the intake for the drinking water plant did not align with the seasonal peak in human Giardiasis cases in this region that are reported annually by public health authorities. This suggests that the risk of contracting Giardiasis from treated drinking water in this community is possibly low when the treatment plant is functioning adequately. Instead, waterborne exposure is likely the result of seasonal behaviours surrounding recreational water use. Therefore, the collective findings of our study are important to help inform future risk management studies and guide public health protection policies.

P202 Increase in diagnoses of early infectious syphilis: local outbreak or following the national trend?

IntroductionThere has been a substantial increase in the incidence of early infectious syphilis (EIS) in our large city clinic, apparent since reconfiguration of services in July 2015.MethodsA retrospective case note review of electronic patient records was undertaken to investigate whether this was due to a local outbreak or in keeping with recent national trend. A database search for primary, secondary &amp; early latent syphilis identified 78 and 116 cases in 2015 and 2016 respectively. These records were assessed using BASHH audit standards and reviewed for various lifestyle risk factors. We worked with Public Health England to address concerns regarding a possible local syphilis outbreak.ResultsOf 168 patients, 85% were MSM: 34% and 28% were HIV positive in 2015 and 2016 respectively. Of the patients with known HIV, 64% were diagnosed as part of their HIV care. Partner notification reached 0.56 contacts per index case. Of the 89 contacts, over 50% were positive for syphilis. Retrospective analysis of surveillance data identified a breakpoint in July 2014 associated with a monthly increase in cases since then with no observable change in patient demographics.DiscussionService reconfiguration focussed on MSM risk groups, coincided with increased EIS diagnoses within 1 year. However, epidemiological analyses indicate a continuum from 2014 following national trend. Routine syphilis screening in HIV care remains an essential tool for early case finding. As 80% were first syphilis infections we are evaluating syphilis point of care testing alongside capillary blood sampling to increase screening in outreach settings.

Temporal Patterns of Influenza A and B in Tropical and Temperate Countries: What Are the Lessons for Influenza Vaccination?

IntroductionDetermining the optimal time to vaccinate is important for influenza vaccination programmes. Here, we assessed the temporal characteristics of influenza epidemics in the Northern and Southern hemispheres and in the tropics, and discuss their implications for vaccination programmes.MethodsThis was a retrospective analysis of surveillance data between 2000 and 2014 from the Global Influenza B Study database. The seasonal peak of influenza was defined as the week with the most reported cases (overall, A, and B) in the season. The duration of seasonal activity was assessed using the maximum proportion of influenza cases during three consecutive months and the minimum number of months with ≥80% of cases in the season. We also assessed whether co-circulation of A and B virus types affected the duration of influenza epidemics.Results212 influenza seasons and 571,907 cases were included from 30 countries. In tropical countries, the seasonal influenza activity lasted longer and the peaks of influenza A and B coincided less frequently than in temperate countries. Temporal characteristics of influenza epidemics were heterogeneous in the tropics, with distinct seasonal epidemics observed only in some countries. Seasons with co-circulation of influenza A and B were longer than influenza A seasons, especially in the tropics.DiscussionOur findings show that influenza seasonality is less well defined in the tropics than in temperate regions. This has important implications for vaccination programmes in these countries. High-quality influenza surveillance systems are needed in the tropics to enable decisions about when to vaccinate.

An Unprecedented High Incidence of Leptospirosis in Futuna, South Pacific, 2004 - 2014, Evidenced by Retrospective Analysis of Surveillance Data.

Futuna is a small Polynesian island in the South Pacific with a population of 3,612 in 2013. The first human leptospirosis case was confirmed in 1997. Active surveillance started in 2004. Cases were confirmed by PCR or real time PCR, or by serology using MAT or a combination of IgM-ELISA and MAT. A retrospective analysis of surveillance data shows that the disease was endemic with a mean annual incidence of 844 cases per 100,000 over an 11-year period from 2004 to 2014. An epidemic peak as high as 1,945 cases per 100,000 occurred in 2008. Serogroup Australis was predominant until 2007, Icterohaemorrhagiae was dominant afterwards. Cluster analysis revealed different hot spots over time. Lifestyle habits, such as walking barefoot in irrigated taro fields or pig pens probably contributed to contamination from the swine and rodent reservoirs to humans. Severe forms were rare, and the case fatality rate was 0.5%. The medical community and general population were aware of leptospirosis and rapid treatment with amoxycillin was the main treatment, probably contributing to this low fatality rate.

Outcomes for surgical and endovascular revision procedures in arteriovenous fistulae: Stevenage experience

s / International Journal of Surgery 12 (2014) S13 S117 S113 Laura McCormack . NHS GGC, Glasgow, UK; NHS Lothian, Edinburgh, UK; NHS Grampian, Aberdeen, UK; NHS Tayside, Dundee, UK. Introduction: Endovascular aneurysm repair (EVAR) is the dominant treatment strategy for Abdominal Aortic Aneurysms. Several large RCTs have demonstrated early survival benefits when compared to open sur gical repair. However long term outcome data is limited. The aim of this study was to investigate long term outcomes following EVAR in Scotland. Methods: Retrospective analysis of surveillance data, between Jan 2001 Dec 2012, in the four main Vascular Units was performed. Patients were identified locally and imaging data was collected by manually searching a combination of databases. Primary outcome measures included operative mortality, aneurysm related mortality and all cause mortality. Secondary outcomemeasures included long term graft related complications and re intervention. Results: Data was available for 569 patients. All centres had data available for a minimum of 5 continuous years. Mean patient agewas 75.6years, 89% were male. Mean follow up was 36.3months. 138 patients were recorded to be cease of which 19 died from aneurysm related causes. 30day mor tality was 1.2%, aneurysm related mortality and all cause mortality at 5 years were 4.5% and 33.5%, respectively. Complications and re interven tion report at 5 years were 44.2% and 11.2%. Conclusions: Operative mortality, aneurysm related mortality and all cause mortality in Scotland are similar to previously published data. Complication rates were also comparable; however re intervention rate were lower. 0383: OUTCOMES FOR SURGICAL AND ENDOVASCULAR REVISION PRO CEDURES IN ARTERIOVENOUS FISTULAE: STEVENAGE EXPERIENCE Khalid Hureibi, Kamal Bushreda, Josh Cohen *, Mike Guest. Lister Hospital,