Sensitivity Of Surveillance System Research Articles

An Emerging Group of Membrane Property Sensors Controls the Physical State of Organellar Membranes to Maintain Their Identity.

The biological membranes of eukaryotic cells harbor sensitive surveillance systems to establish, sense, and maintain characteristic physicochemical properties that ultimately define organelle identity. They are fundamentally important for membrane homeostasis and play active roles in cellular signaling, protein sorting, and the formation of vesicular carriers. Here, we compare the molecular mechanisms of Mga2 and Ire1, two sensors involved in the regulation of fatty acid desaturation and the response to unfolded proteins and lipid bilayer stress in order to identify their commonalities and specializations. We will speculate on the cellular significance of membrane property sensors in other organelles and discuss their putative mechanisms. Based on these findings, we propose membrane property sensors as an emerging class of proteins with wide implications for organelle communication and function.

Optimising cost-effectiveness of freedom from disease surveillance—Bluetongue Virus Serotype 8 as an example

The aim of this study was to propose a procedure for optimising the cost-effectiveness of vector borne disease surveillance using a scenario tree model and cost-effectiveness analysis. The surveillance systems for Bluetongue Virus serotype 8 (BTV-8) implemented in Switzerland and Belgium were used as examples. In twenty four different, simulated population structures, passive surveillance and five designs of active surveillance were investigated. The influence of surveillance system design and parameters such as farmer disease awareness, veterinary disease awareness, herd and within-herd design prevalence on the overall surveillance system sensitivity were assessed. Furthermore, the cost-effectiveness of mandatory and voluntary vaccination regimes in relation to disease surveillance was investigated.Under the assumption that BTV-8 manifests clinically, freedom from disease in a population can be established with almost certainty over the period of one year using clinical surveillance alone. Additional investment in active surveillance would therefore economically only be justified, if no clinical manifestation is suspected or other surveillance objectives are to be provided such as early detection. The best cost-effectiveness is obtained by sampling more herds rather than more animals within a herd. Mandatory vaccination reduces the cost of surveillance by 0.26 € per vaccine and voluntary vaccination only marginally reduces the cost of risk-based surveillance, by reducing the population at risk. Finally, in populations with predominantly dairy cattle, bulk-tank milk testing is the method of choice to actively demonstrate freedom from disease.

The effect of genetic susceptibility and targeting of sampling on the sensitivity of the surveillance system and certainty-of-freedom for classical scrapie in Finland in 2008–2014

We applied scenario tree modeling to study how the genetic distribution of the sheep population in Finland and the focusing on fallen stock would influence the surveillance sensitivity of scrapie. To incorporate the unevenly distributed susceptibility into the estimation we used data from GB where the genetic distribution and scrapie occurrence have been documented in both normally slaughtered and deceased animals. Finland’s sheep population is more susceptible to scrapie than the sheep population in GB and surveillance is concentrated on fallen stock. As a result, there is high systemic sensitivity in Finland even with the moderate number of studied animals. The certainty of the freedom-of-disease status is clearly elevated by the low probability of previous disease occurrence and low probability of introduction. The results highlight the need to change the concept from surveillance system sensitivity to freedom-of-disease status and to also consider the risk of introduction and the cumulative nature of the disease prevalence information due repeated surveillance efforts.

Sensitivity and positive predictive value of the measles surveillance system in Uganda, 2012-2015

Introduction : disease surveillance is a critical component in the control and elimination of vaccine preventable diseases. The Uganda National Expanded Program on Immunization strives to have a sensitive surveillance system within the Integrated Disease Surveillance and Response (IDSR) framework. We analyzed measles surveillance data to determine the effectiveness of the measles case-based surveillance system and estimate its positive predictive value in order to inform policy and practice. Methods : an IDSR alert was defined as 1 suspected measles case reported by a district in a week, through the electronic Health Management Information System. We defined an alert in the measles case-based surveillance system (CBS) as 1 suspected measles case with a blood sample collected for confirmation during the corresponding week in a particular district. Effectiveness of CBS was defined as having 80% of IDSR alerts with a blood sample collected for laboratory confirmation. Positive predictive value was defined as the proportion of measles case-patients who also had a positive measles serological result (IgM +). We reviewed case-based surveillance data with laboratory confirmation and measles surveillance data from the electronic Health Management Information System from 2012-2015. Results : a total of 6,974 suspected measles case-persons were investigated by the measles case-based surveillance between 2012 and 2015. Of these, 943 (14%) were measles specific IgM positive. The median age of measles case-persons between 2013 and 2015 was 4.0 years. Between 2013 and 2015, 72% of the IDSR alerts reported in the electronic Health Management Information System, had blood samples collected for laboratory confirmation. This was however less than the WHO recommended standard of 80%. The PPV of CBS between 2013 and 2015 was 8.6%. Conclusion : effectiveness of measles case-based surveillance was sub-optimal, while the PPV showed that true measles cases have significantly reduced in Uganda. We recommended strengthening of case-based surveillance to ensure that all suspected measles cases have blood samples collected for laboratory confirmation to improve detection and ensure elimination by 2020.

Trends of measles in Namibia, a secondary data analysis: 2012-2015

Introduction: measles is one of the vaccines preventable diseases (VPD) which are currently under surveillance in Namibia, due to the high incidence of cases reported worldwide rendering it a public health concern. We determined the trends of measles in Namibia and described the data in terms of person, place and time. Methods: we reviewed secondary data from the National Health Information System database on Measles from 2012-2016. The surveillance system detects cases based on the standard case definition for measles which includes any person, suspected by clinician having measles infection, or, any person with fever and maculopapular rash and cough, coryza or conjunctivitis. Diagnosis is confirmed by positive measles IgM laboratory result, or a suspected case epi linked to a confirmed case. We analyzed the data using Epi info version 7.2, frequencies were derived and data was described in terms of person, place and time. Results: during the 5-year period, a total of 1846 (26.86%) measles cases were confirmed by either IgM positive laboratory result or epidemiological link, out of 6873 reported cases. The trends of positive measles cases were 82 (17.26%) in 2012, 467 (35.43%) in 2013, 1069 (44.91%) in 2014, 196 (8.39%) in 2015 and 32 (8.79%) in 2016 (p-value < 0.001). Over the 5 years, the majority of cases were detected among children aged 0-10 years, 784 (42.47%). The mean age being 13.7 years, with a SD of 11.8 years. The median age of 9 years and mode of 1 year. The ratio of affected males to females was 1.05:1. Conclusion: only 26.86% of reported cases were found to be positive for measles, this is attributed to the sensitivity of the surveillance system. During the years 2013 and 2014 Namibia experienced measles outbreaks, which was detected by the surveillance system. Children under the age of 10 were most affected age group over the 5-year period, which raises concerns about vaccine efficacy and immunization coverage in that population group. We recommend a study on vaccine efficacy and immunization coverage.

Progress towards a leprosy-free country: The experience of Oman.

IntroductionThe World Health Organization (WHO) released the Global Leprosy Strategy 2016–2020 towards a leprosy-free world. The author described the progress made towards the elimination of leprosy and suggested recommendations for the acceleration towards a Leprosy-free country according to WHO laid out criterion.MethodologyCase record review of Leprosy patients managed between the years 1992 to 2015 were registered and analyzed. Data were collected from annual reports of the Ministry of Health including demographics, classification of leprosy new cases, relapse, childhood, grades of disability (GD) and multidrug therapy (MDT) completion rates.ResultsLeprosy prevalence rate declined from 1.64 to 0.09 per 10,000 population during the period 1992 and 2015 (p<0.0001). Between 2005 and 2015, 77 patients were diagnosed with Leprosy as per definition and 75/77 (98%) had smear or biopsy positive. Of these, 53 (69%) cases were among foreign-born (non-national) (p<0.003) and 19 (25%) were among women. Most of the leprosy cases were notified in Muscat governorate 29 (38%) and among patients between 25–44 years of age 41 (53%), followed by ≥45 years 29 (38%) and 6 (8%) were children age ≤ 14 years. Multi-bacillary (MB) cases reported 60 versus 17 for Pauci-bacillary (PB) (p< 0.01), while MB was highest among both nationals (83%) and foreign-born (75%).MDT completion rate was 100% and no relapse cases were notified among nationals. The rate of new patients diagnosed with leprosy related disability was 2.3 per million population, and grade 2 disability (G2D) rate among nationals was 0.9 per million population. No disability was recorded among women or children less than 14 years within the nationals group from 2013. Almost all the foreign-born patients didn’t complete their treatment in Oman as they left the country shortly after diagnosis of leprosy due to a very short term contract, discretionary employment practices by the employers and prefer to go home to complete their treatment.ConclusionOman has met the elimination goals and made great strides towards becoming a leprosy-free country. However, challenges such as improving surveillance system efficiency and sensitivity for detecting timely leprosy cases, as well as foreign-born workers are still a major concerns.

Positive predictive value and effectiveness of measles case-based surveillance in Uganda, 2012-2015.

IntroductionDisease surveillance is a critical component in the control and elimination of vaccine preventable diseases. The Uganda National Expanded Program on Immunization strives to have a sensitive surveillance system within the Integrated Disease Surveillance and Response (IDSR) framework. We analyzed measles surveillance data to determine the effectiveness of the measles case-based surveillance system and estimate its positive predictive value in order to inform policy and practice.MethodsAn IDSR alert was defined as ≥1 suspected measles case reported by a district in a week, through the electronic Health Management Information System. We defined an alert in the measles case-based surveillance system (CBS) as ≥1 suspected measles case with a blood sample collected for confirmation during the corresponding week in a particular district. Effectiveness of CBS was defined as having ≥80% of IDSR alerts with a blood sample collected for laboratory confirmation. Positive predictive value was defined as the proportion of measles case-patients who also had a positive measles serological result (IgM +). We reviewed case-based surveillance data with laboratory confirmation and measles surveillance data from the electronic Health Management Information System from 2012–2015.ResultsA total of 6,974 suspected measles case-persons were investigated by the measles case-based surveillance between 2012 and 2015. Of these, 943 (14%) were measles specific IgM positive. The median age of measles case-persons between 2013 and 2015 was 4.0 years. Between 2013 and 2015, 72% of the IDSR alerts reported in the electronic Health Management Information System, had blood samples collected for laboratory confirmation. This was however less than the WHO recommended standard of ≥80%. The PPV of CBS between 2013 and 2015 was 8.6%.ConclusionIn conclusion, the effectiveness of measles case-based surveillance was sub-optimal, while the PPV showed that true measles cases have significantly reduced in Uganda. We recommended strengthening of case-based surveillance to ensure that all suspected measles cases have blood samples collected for laboratory confirmation to improve detection and ensure elimination by 2020.

Development of a stochastic agent-based model to evaluate surveillance strategies for detection of emergent porcine reproductive and respiratory syndrome strains

BackgroundThe objective of the current study was to develop a stochastic agent-based model using empirical data from Ontario (Canada) swine sites in order to evaluate different surveillance strategies for detection of emerging porcine reproductive and respiratory syndrome virus (PRRSV) strains at the regional level. Four strategies were evaluated, including (i) random sampling of fixed numbers of swine sites monthly; (ii) risk-based sampling of fixed numbers, specifically of breeding sites (high-consequence sites); (iii) risk-based sampling of fixed numbers of low biosecurity sites (high-risk); and (iv) risk-based sampling of breeding sites that are characterized as low biosecurity sites (high-risk/high-consequence). The model simulated transmission of a hypothetical emerging PRRSV strain between swine sites through three important industry networks (production system, truck and feed networks) while considering sites’ underlying immunity due to past or recent exposure to heterologous PRRSV strains, as well as demographic, geographic and biosecurity-related PRRS risk factors. Outcomes of interest included surveillance system sensitivity and time to detection of the three first cases over a period of approximately three years.ResultsSurveillance system sensitivities were low and time to detection of three first cases was long across all examined scenarios.ConclusionTraditional modes of implementing high-risk and high-consequence risk-based surveillance based on site’s static characteristics do not appear to substantially improve surveillance system sensitivity. Novel strategies need to be developed and considered for rapid detection of this and other emerging swine infectious diseases. None of the four strategies compared herein appeared optimal for early detection of an emerging PPRSV strain at the regional level considering model assumptions, the underlying population of interest, and absence of other forms of surveillance.

Measles epidemic in Brazil in the post-elimination period: Coordinated response and containment strategies

The measles virus circulation was halted in Brazil in 2001 and the country has a routine vaccination coverage against measles, mumps and rubella higher than 95%. In Ceará, the last confirmed case was in 1999. This article describes the strategies adopted and the effectiveness of surveillance and control measures implemented during a measles epidemic in the post-elimination period. The epidemic started in December 2013 and lasted 20 months, reaching 38 cities and 1,052 confirmed cases. The D8 genotype was identified. More than 50,000 samples were tested for measles and 86.4% of the confirmed cases had a laboratory diagnosis. The beginning of an campaign vaccination was delayed in part by the availability of vaccine. The classic control measures were not enough to control the epidemic. The creation of a committee of experts, the agreement signed between managers of the three spheres of government, the conducting of an institutional active search of suspected cases, vaccination door to door at alternative times, the use of micro planning, a broad advertising campaign at local media and technical operative support contributed to containing the epidemic. It is important to recognize the possibility of epidemics at this stage of post-elimination and prepare a sensitive surveillance system for timely response.

Strengthening Laboratory Capacity for Early Warning Alert and Response System (EWARS) in Indonesia

Background: Establishment of Early Warning Alert and Response System (EWARS) in Indonesia was initiated since 2009 in few selected provinces and government was planning to roll out in other provinces. Before initiating this roll out the assessment of performance of EWARS in 2012 was conducted. The aim of the assessment is to strengthen laboratory for supporting to EWARS for alerts testing. Methods: Laboratory capacity mapping tool and laboratory algorithm for twenty two priority diseases of EWARS were developed. This mapping tool was used in nine provinces to look at the existing capacities. This mapping tool and algorithm is used to pilot the laboratory support function for EWARS in four districts of West Kalimantan. Results: Almost all alerts have no laboratory confirmation except for few disease like measles, poliomyelitis and malaria. Capacity mapping of five of the nine provinces have available capacity for testing for bacteriology, virology, parasitology, mycology, hematology, immunology and environmental/chemicals in public or private sectors. A piloting of laboratory support for EWARS demonstrated the application of algorithm, development of logistic planning and allocation of resources for laboratory testing for alerts of EWARS. Conclusion: Capacity mapping opens horizon on strengthening support function of the system, which are readily available at local levels and provides opportunities for coordination and collaboration. EWARS is an opportunity to strengthen sustainable and sensitive surveillance system, which in turn assist on overall of health development through health systems strengthening.

Measles outbreak investigation in Guji zone of Oromia Region, Ethiopia.

IntroductionDespite the increase of immunization coverage (administrative) of measles in the country, there are widespread outbreaks of measles. In this respect, we investigated one of the outbreaks that occurred in hard to reach kebeles of Guji Zone, Oromia region, to identify the contributing factors that lead to the protracted outbreak of measles.MethodsWe used a cross-sectional study design to investigate a measles outbreak in Guji zone, Oromia region. Data entry and analysis was performed using EPI-Info version 7.1.0.6 and MS-Microsoft Excel.ResultsIn three months' time a total of 1059 suspected cases and two deaths were reported from 9 woredas affected by a measles outbreak in Guji zone. The cumulative attack rate of 81/100,000 population and case fatality ratio of 0.2% was recorded. Of these, 821 (77.5%) cases were < 15 years of age, and 742 (70%) were zero doses of measles vaccine. Although, all age groups were affected under five years old were more affected 495 (48%) than any other age groups. In response to the outbreak, an outbreak response immunization was organized at the 11th week of the epidemic, when the epidemic curve started to decline. 6 months to14 years old were targeted for outbreak response immunization and the overall coverage was 97 % (range: 90-103%). Case management with vitamin A supplementation, active case search, and health education was some of the activities carried out to curb the outbreak.ConclusionWe conclude that low routine immunization coverage in conjunction with low access to routine immunization in hard to reach areas, low community awareness in utilization of immunization service, inadequate cold chain management and delivery of a potent vaccine in hard to reach woredas/kebeles were likely contributed to the outbreak that's triggered a broad spread epidemic affecting mostly children without any vaccination. We also figured that the case-based surveillance lacks sensitivity and timely confirmation of the outbreak, which as a result outbreak response immunization were delayed. We recommend establishing reaching every child (REC) strategy in Guji zone with particular emphasis too hard reach areas to enhance the current immunization service, and furthermore to conduct data quality self-assessment or cluster coverage survey to verify the reported high vaccination coverage in some kebeles. We also recommend conducting the second opportunity as a form of supplemental immunization activities in 2-3 year interval or consider the national second dose introduction in the routine immunization system to improve population immunity. We further recommend that there is a need to boost the sensitivity of case-based surveillance system to be able to early detect, confirm and react to future epidemics.

Schistosomiasis control progress and endemic situation in Sichuan Province

To understand the schistosomiasis control progress and endemic situation, so as to provide the evidence for formulating the strategy of schistosomiasis elimination in Sichuan Province. The schistosomiasis history data, working reports of schistosomiasis prevention and control, schistosomiasis surveillance data, and data of schistosomiasis prevention and control capacity were collected and analyzed for the schistosomiasis control progress and epidemic situation in Sichuan Province from 2004 to 2015. There were 63 schistosomiasis endemic districts in 11 cities in Sichuan Province, and the standard of schistosomiasis transmission interruption was achieved in the whole province in 2015. Currently, the area with Oncomelania hupensis snails was 2 537.54 hm2, and there were 1 769 advanced schistosomiasis patients. From 2004 to 2015, the accumulated survey area with snails was 433 065.80 hm2, and the area of snail control by molluscicides was 251 259 hm2. There were 26.017 144 million person-times of schistosomiasis blood tests and 7.89 million person-times of chemotherapy. There were 1.276 117 million head-times of cattle that received the schistosomiasis examinations. The schistosomiasis patients and livestock and the area with snails were decreased year by year. Since 2010, there were no local schistosome-infected residents and livestock and since 2004, there were no schistosome-infected snails. However, in some area, the professional personnel were less, the technology and hardware lagged behind, and the schistosomiasis prevention and control capacity was weak. Sichuan Province achieved the standard of schistosomiasis transmission interruption in 2015. In the future, the comprehensive schistosomiasis prevention and control strategy still should be strengthened, including the promotion of schistosomiasis prevention and control capacity, establishment of sensitive early-warning surveillance system, and implementation of accurate schistosomiasis prevention and control, in order to consolidate the control achievements and realize the aim of schistosomiasis elimination as soon as possible.

Genetic disease susceptibility and surveillance system sensitivity: Classical scrapie

Genetic disease susceptibility and surveillance system sensitivity: Classical scrapie

Influence of data quality on early warning sensitivity of syndromic surveillance system based on medical institutions

Objective: To evaluate the influence of data quality on the sensitivity of early warning syndromic surveillance system based on medical institutions in Qianjiang, Hubei province and explore the relationship between data quality and sensitivity of early warning of the system. Methods: The delay reporting rate and underreporting rate were calculated for the evaluation of the data quality. Data obtained from semi-synthetic simulated outbreak and area under the curve (AUC) were used in combination to test the sensitivity of early warning of various models and select the optimal model. Time-series generalized additive model (GAM) was used to analyze the curve fitting and threshold effect between data quality and early warning sensitivity of the system. Results: A total of 179 905 cases were reported from April 1, 2012 to January 31, 2014, in which 8 744 were not reported timely (16.45%). Averagely 416 reporting were delayed in each month. There were 2 566 cases which were underreported (4.83%). Compared with other early warning models, i.e. Cumulative Sum (CUSUM), Shewhart, Exponentially Weighted Moving Average (EWMA), Early Aberration Reporting System (EARS-3C), the MA model had the maximum area under the curve (AUC=0.93), and the difference was significant (P<0.001). The early warning sensitivity ranged from 84.89% to 97.25% during the operation period of the syndromic surveillance system. Underreporting had influence on early warning sensitivity, when underreporting rate was over 2.78%, the sensitivity would decrease obviously. No obvious associations were observed between the delay reporting rate and early warning sensitivity of the system. Conclusion: The data quality had influence on the early warning sensitivity of the syndromic surveillance system based on medical institution in Qianjiang. In the context of this study, underreporting had the main influence on the sensitivity of early warning.

Assessing the sensitivity of European surveillance for detecting BSE in cattle according to international standards

European surveillance for Bovine Spongiform Encephalopathy (BSE), initiated in 2001, has shown a steady exponential decline in the number of infected cattle, demonstrating that control measures have been effective. In 2016 23 European countries out of 28 demonstrated negligible risk status for the disease. The international standard setting body, the World Organization for Animal Health (OIE), prescribes that for countries where there is a non-negligible BSE risk, surveillance should allow the detection of one case per 100,000 in the adult cattle population with 95% confidence (Type A surveillance). The Cattle TSE Monitoring Model (C-TSEMM) was developed to estimate the sensitivity of surveillance systems to detect BSE in cattle. The model includes a cohort-based back calculation model to estimate the number and age of infected animals, the subset of those that are detectable by the diagnostic test, and the stream by which infected animals exit the standing population, that is, healthy slaughter, emergency slaughter, fallen stock and clinical suspects. Data collected by the European Commission (EC) and European Food Safety Authority (EFSA), containing the details of over 91 million cattle tested within the European Member States (EU25) surveillance scheme from 2002 to 2011, was used to populate the model.When considering the EU25 surveillance scheme as a single epidemiological unit, the model estimated that the surveillance scheme in place exceeded the OIE required threshold for Type A surveillance, and that a revised monitoring system excluding all healthy slaughter animals would also exceed this threshold.Results indicated a variation in individual country sensitivity of surveillance with seven countries (Germany, Spain, France, Ireland, Italy, Poland and the UK) exceeding the required threshold individually. Key assumptions included the fitting of an exponential distribution for all countries to describe the decline in prevalence over time and, for those members with no detected cases of BSE, an estimated area prevalence was used as a proxy. These results were part of the evidence base that lifted the testing requirement for healthy slaughter animals in European countries in 2013. The model has been maintained and updated by EFSA each year with the addition of new member states, and updated surveillance data.

Assessing the sensitivity of bovine tuberculosis surveillance in Canada’s cattle population, 2009–2013

The objectives of this study were (1) to estimate the annual sensitivity of Canada’s bTB surveillance system and its three system components (slaughter surveillance, export testing and disease investigation) using a scenario tree modelling approach, and (2) to identify key model parameters that influence the estimates of the surveillance system sensitivity (SSSe). To achieve these objectives, we designed stochastic scenario tree models for three surveillance system components included in the analysis. Demographic data, slaughter data, export testing data, and disease investigation data from 2009 to 2013 were extracted for input into the scenario trees. Sensitivity analysis was conducted to identify key influential parameters on SSSe estimates.The median annual SSSe estimates generated from the study were very high, ranging from 0.95 (95% probability interval [PI]: 0.88–0.98) to 0.97 (95% PI: 0.93–0.99). Median annual sensitivity estimates for the slaughter surveillance component ranged from 0.95 (95% PI: 0.88–0.98) to 0.97 (95% PI: 0.93–0.99). This shows that slaughter surveillance to be the major contributor to overall surveillance system sensitivity with a high probability to detect M. bovis infection if present at a prevalence of 0.00028% or greater during the study period. The export testing and disease investigation components had extremely low component sensitivity estimates—the maximum median sensitivity estimates were 0.02 (95% PI: 0.014–0.023) and 0.0061 (95% PI: 0.0056–0.0066) respectively.The three most influential input parameters on the model’s output (SSSe) were the probability of a granuloma being detected at slaughter inspection, the probability of a granuloma being present in older animals (≥12 months of age), and the probability of a granuloma sample being submitted to the laboratory. Additional studies are required to reduce the levels of uncertainty and variability associated with these three parameters influencing the surveillance system sensitivity.

Measles.

Measles is an infectious disease in humans caused by the measles virus (MeV). Before the introduction of an effective measles vaccine, virtually everyone experienced measles during childhood. Symptoms of measles include fever and maculopapular skin rash accompanied by cough, coryza and/or conjunctivitis. MeV causes immunosuppression, and severe sequelae of measles include pneumonia, gastroenteritis, blindness, measles inclusion body encephalitis and subacute sclerosing panencephalitis. Case confirmation depends on clinical presentation and results of laboratory tests, including the detection of anti-MeV IgM antibodies and/or viral RNA. All current measles vaccines contain a live attenuated strain of MeV, and great progress has been made to increase global vaccination coverage to drive down the incidence of measles. However, endemic transmission continues in many parts of the world. Measles remains a considerable cause of childhood mortality worldwide, with estimates that >100,000 fatal cases occur each year. Case fatality ratio estimates vary from <0.01% in industrialized countries to >5% in developing countries. All six WHO regions have set goals to eliminate endemic transmission of MeV by achieving and maintaining high levels of vaccination coverage accompanied by a sensitive surveillance system. Because of the availability of a highly effective and relatively inexpensive vaccine, the monotypic nature of the virus and the lack of an animal reservoir, measles is considered a candidate for eradication.

Acute Flaccid Paralysis Surveillance in Central of Iran, 2003 To 2007: a Multicenter Study

Purpose: To examine the national program indicators for Acute flaccid paralysis (AFP) surveillance system in Isfahan and Markazi provinces of Iran. Methods: This is an evaluation study assessing indicators of acute flaccid paralysis surveillance system in Isfahan and Markazi provinces. All data registered for suspected AFP cases in departments of communicable diseases in health deputy of the mentioned provinces were reviewed. These documents included linear lists, patient records, national polio lab results, and classification committee reports. Demographic information and specific AFP surveillance indicators such as AFP number and non-polio AFP rate were obtained and calculated exactly, finally being compared with the available standards. Data analysis was performed by SPSS statistical software package. Results: Five-year mean values for all indicators (AFP number, non-polio AFP rate, AFP reported and tested within 48 hours of onset , AFP detected after 7 days, AFP with two stool specimens in 14 days, Stool specimens send to lab in 3 days , AFP cases followed up in 60 days) in both provinces were above the standard rate. Conclusion: Our study showed AFP surveillance system in central parts of Iran worked effectively and appropriately, however, it is necessary to regularly monitor ongoing process of this sensitive surveillance system.

Estimating the sensitivity of passive surveillance for HPAI H5N1 in Bayelsa state, Nigeria

This study identified characteristics of poultry farming with a focus on practices that affect the detection of HPAI; and estimated the system sensitivity of passive surveillance for HPAI H5N1 in commercial and backyard chicken farms in Bayelsa-State, Nigeria. Field studies were carried out in Yenegoa and Ogbia local government areas in Bayelsa state. Willingness to report HPAI was highest in commercial poultry farms (13/13) than in Backyard farms (8/13). Poor means of dead bird disposal was common to both commercial and backyard farms. Administering some form of treatment to sick birds without prior consultation with a professional was higher in backyard farms (8/13) than in commercial farms (4/13). Consumption of sick birds was reported in 4/13 backyard farms and sale of dead birds was recorded in one commercial farm. The sensitivity of passive surveillance for HPAI was assessed using scenario tree modelling. A scenario tree model was developed and applied to estimate the sensitivity, i.e. the probability of detecting one or more infected chicken farms in Bayelsa state at different levels of disease prevalence. The model showed a median sensitivity of 100%, 67% and 23% for detecting HPAI by passive surveillance at a disease prevalence of 0.1%, a minimum of 10 and 3 infected poultry farms respectively. Passive surveillance system sensitivity at a design prevalence of 10 infected farms is increasable up to 86% when the disease detection in backyard chicken farms is enhanced.

Importation and outbreak of wild polioviruses from 2000 to 2014 and interruption of transmission in Cameroon

BackgroundEfficient implementation of the global eradication strategies consisting of Acute Flaccid Paralysis (AFP) surveillance and mass immunization campaigns led to interruption of indigenous wild poliovirus transmission in Cameroon in 1999. ObjectivesThis study describes type 1 and type 3 wild poliovirus (WPV) importation, incidence, geographic distribution and control since the original interruption of transmission in Cameroon. Study designStool samples from AFP patients under the age of 15 years in Cameroon were collected nationwide and subjected to virus isolation on RD and L20B cell cultures. Resulting virus isolates were typed by intratypic differentiation (ITD) and analysis of the VP1 coding sequence of the viral genome. Surveillance data originating from Cameroon between 2000 and 2014 were considered for retrospective descriptive analyses. ResultsFrom 2003 to 2009, multiple WPV importation events from neighboring countries affected mainly in the northern regions of Cameroon but did not led to sustained local transmission. Throughout this period, 16 WPV1 and 5 WPV3 were detected and identified as members of multiple clusters within type-specific West Africa B genotypes (WEAF-B). In 2013–2014, a polio outbreak associated to a highly evolved (“orphan”) WPV1 affected four southern regions of Cameroon. ConclusionsThe appearance of highly evolved lineage of type 1 WPV suggests potential surveillance gap and underscore the need to maintain comprehensive polio immunization activities and sensitive surveillance systems in place as long as any country in the world remains endemic for WPV.