Passive surveillance of African Swine Fever (ASF) in wild boars as an effective tool for prevention, control and eradication of ASF: A new approach

The latest recommendations of the European Commission and the scientific opinions of the EFSA and other bodies define the passive surveillance of ASF in wild boars as a key means of epidemiological surveillance and a basic tool for the eradication of the ASF virus from the natural environment in the areas where this disease occurs, especially in the early stage of its development. The key to eradication is the management of the wild boar population and its reduction to a low and controlled number, so as to diminish the virus pressure in the environment and lessen the risk to pig farms. Wild boar hunting should take place in a planned manner that is adapted to the epizootic situation (as part of centrally managed hunting and sanitary culling). The most intensive hunting should take place in ASF-free areas, with the use of tailored methods and the latest technologies. Periodic hunting moratoria and restrictions on any activity in newly infected zones are necessary. This approach provides for phased eradication of the infectious agent by culling or capturing wild boars, as well as identifying and safely removing their carcasses and remains. When passive ASF surveillance in wild fauna is undertaken, data on the incidence of the disease in wild boars are obtained by the Veterinary Inspectorate without its active participation. The inspectorate is notified of any suspicion or occurrence of the disease, including discoveries of carcasses of animals of susceptible species. Then it acts according to an established plan including clinical examination of suspected or sick animals, anatomopathological examinations and sample collection for laboratory tests. The article describes the use of passive ASF surveillance in wild boars as a tool to prevent, control and combat ASF in Poland.

Passive epidemiological surveillance in wildlife in Costa Rica identifies pathogens of zoonotic and conservation importance

Epidemiological surveillance systems for pathogens in wild species have been proposed as a preventive measure for epidemic events. These systems can minimize the detrimental effects of an outbreak, but most importantly, passive surveillance systems are the best adapted to countries with limited resources. Therefore, the present study aims to evaluate the technical and infrastructural feasibility to establish this type of scheme in Costa Rica targeting thedetection of pathogens of zoonotic and conservation importance in wildlife. Between 2018 and 2020, 85 carcasses of free-ranging vertebrates were admitted for post mortem analysis and complementary laboratory analysis, representing a solid basis for the implementation of a passive surveillance system for wildlife diseases in the country. However, we encounter during this research significant constraints that affected the availability of carcasses for analysis, mainly related to the initial identification of cases, detection biases towards events in populated- or easily accessible-areas with nearby located wildlife management centers, further associated with financial disincentives, and limited local logistics capacity. Thus resulting in the exclusion of some geographic regions of the country. This epidemiological surveillance scheme allowed us to estimate the general state of health of the country's wildlife, establishing the cause of death of the analyzed animals as follows: (i) 46 (54.1%) traumatic events, (ii) 23 (27.1%) infectious agents, (iii) two (2.4%) degenerative illness, (iv) three (3.5%) presumably poisoning, and (v) in 11 (12.9%)undetermined. It also allowed the detection of pathogens such as, canine distemper virus, Klebsiella pneumoniae, Toxoplasma gondii, Trypanosoma spp., Angiostrongylus spp., Dirofilaria spp., Baylisascaris spp., among others. As well as recognizing the circulation of these pathogens around national territory and also on those analyzed species. This strategy is crucial in geographical regions defined as critical for the appearance of diseases due to their great biodiversity and social conditions.

821. Changes in Cleaning Practices and Non-conventional Personal Protective Equipment Use due to SARS-CoV-2 and Association with Increases in Multi-drug Resistant Organism Cases

Background During the pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), policy at a Minnesota hospital changed to state that environmental services would not clean rooms of patients with confirmed or suspected SARS-CoV-2 infections, requiring nursing staff to perform these duties. Investigation of a cluster of carbapenem-resistant Enterobacterales (CRE) in patients hospitalized in the same or adjoining rooms on the medical intensive care unit (MICU) raised concern over whether SARS-CoV-2 cleaning practices and non-conventional personal protective equipment (PPE) use led to transmission of multi-drug resistant organisms (MDROs). Methods Infection Prevention conducts passive surveillance for MDRO acquisition in inpatient units. Passive surveillance of SARS-CoV-2 was performed early in the pandemic. Active surveillance SARS-CoV-2 testing on admission was initiated in July 2020 and active surveillance testing for admitted patients every 7 days was initiated in December. Incident cases of vancomycin-resistant Enterococcus (VRE), extended-spectrum-β-lactamase-producing organisms (ESBL), methicillin-resistant S. aureus (MRSA), and CRE were determined for hospitalized patients between March 1, 2020 and February 28, 2021, excluding patients with infection on admission. Rates of hospitalized patients testing positive for SARS-CoV-2 per 100 patient days were compared to rates of patients testing positive for VRE, ESBL, MRSA, and CRE per 100 patient days respectively. The same rate comparisons were completed for the MICU. Using the F-Test Two-Sample to determine variance, the Two-Sample T-test assuming unequal variances was applied to each comparison. Results Correlation was significant between rates of SARS-CoV-2 and VRE (p< 0.005), ESBL (p< 0.005), MRSA (p< 0.005), and CRE (p< 0.005) (Table 1). MICU correlation was significant between rates of SARS-CoV-2 and VRE (p< 0.005), ESBL (p< 0.005), MRSA (p< 0.005), and CRE (p< 0.005) (Table 2). Table 1: Two-sample T-test results assuming unequal variances: Hospital COVID rates per 100 patient days vs. rates of incident positive tests for VRE, ESBL, MRSA, and CRE per 100 patient days Table 2: Two-sample T-test results assuming unequal variances: MICU COVID rates per 100 patient days vs. rates of incident positive tests for VRE, ESBL, MRSA, and CRE per 100 patient days Conclusion The relationships between the rates of SARS-CoV-2 and four MDROs were statistically significant. It can be inferred from this data that changes in hospital cleaning and non-conventional PPE use may have led to an increase in transmission of MDROs in this facility. Disclosures All Authors: No reported disclosures

Monitoring Risk: Tick and Borrelia burgdorferi Public Participatory Surveillance in the Canadian Maritimes, 2012–2020

Ticks are vectors of many diseases, including Lyme disease (Ld). Lyme disease is an emerging disease in Canada caused by infection with the Lyme borreliosis (Lb) members of the Borrelia genus of spirochaete bacteria, of which Borrelia burgdorferi is regionally the most prevalent. The primary tick vector in central and eastern Canada, Ixodes scapularis, is increasing in numbers and in the geographical extent of established populations. This study documents the distribution of ticks recovered by passive surveillance, and their B. burgdorferi infection prevalence, in three Canadian Maritime provinces from 2012–2020. These regions represent areas in which tick populations are widely established, establishing, and considered non-established. Using a community science approach by partnering with veterinarians and members of the public, we collected over 7000 ticks from the 3 provinces. The three species found most often on companion animals and humans were I. scapularis (76.9%), Ixodes cookei (10.4%) and Dermacentor variabilis (8.9%). The most common hosts were dogs (60.5%), cats (16.8%) and humans (17.6%). As is typical of passive surveillance tick collections, the majority of ticks recovered were adult females; for I. scapularis 90.2%, 5.3%, 3.9% and 0.6% of the total of 5630 ticks recovered for this species were adult females, adult males, nymphs and larvae, respectively. The majority of B. burgdorferi-infected ticks were I. scapularis, as expected. Borrelia infection prevalence in I scapularis was higher in Nova Scotia (20.9%), the province with the most endemic regions, than New Brunswick (14.1%) and Prince Edward Island (9.1%), provinces thought to have established and non-established tick populations, respectively. The province-wide Borrelia infection prevalence generally increased in these latter tow provinces over the course of the study. The host did not have a significant effect on B. burgdorferi infection prevalence; I. scapularis ticks from dogs, cats, humans was, 13.3% (n = 3622), 15.6% (n = 817), 17.9% (n = 730), respectively. No I. scapularis larvae were found infected (n = 33) but B. burgdorferi was detected in 14.8% of both adults (n = 5140) and nymphs (n = 215). The incidence of B. burgdorferi infection also did not differ by engorgement status 15.0% (n = 367), 15.1% (n = 3101) and 14.4% (n = 1958) of non-engorged, engorged and highly engorged ticks, respectively, were infected. In New Brunswick, at the advancing front of tick population establishment, the province-wide infection percentages generally increased over the nine-year study period and all health district regions showed increased tick recoveries and a trend of increased percentages of Borrelia-infected ticks over the course of the study. Within New Brunswick, tick recoveries but not Borrelia infection prevalence were significantly different from endemic and non-endemic regions, suggesting cryptic endemic regions existed prior to their designation as a risk area. Over the 9 years of the study, tick recoveries increased in New Brunswick, the primary study region, and I. scapularis recoveries spread northwards and along the coast, most but not all new sites of recoveries were predicted by climate-based models, indicating that ongoing tick surveillance is necessary to accurately detect all areas of risk. Comparison of tick recoveries and public health risk areas indicates a lag in identification of risk areas. Accurate and timely information on tick distribution and the incidence of Borrelia and other infections are essential for keeping the public informed of risk and to support disease prevention behaviors.

Incursion of European Bat Lyssavirus 1 (EBLV-1) in Serotine Bats in the United Kingdom

Lyssaviruses are an important genus of zoonotic viruses which cause the disease rabies. The United Kingdom is free of classical rabies (RABV). However, bat rabies due to European bat lyssavirus 2 (EBLV-2), has been detected in Daubenton’s bats (Myotis daubentonii) in Great Britain since 1996, including a fatal human case in Scotland in 2002. Across Europe, European bat lyssavirus 1 (EBLV-1) is commonly associated with serotine bats (Eptesicus serotinus). Despite the presence of serotine bats across large parts of southern England, EBLV-1 had not previously been detected in this population. However, in 2018, EBLV-1 was detected through passive surveillance in a serotine bat from Dorset, England, using a combination of fluorescent antibody test, reverse transcription-PCR, Sanger sequencing and immunohistochemical analysis. Subsequent EBLV-1 positive serotine bats have been identified in South West England, again through passive surveillance, during 2018, 2019 and 2020. Here, we confirm details of seven cases of EBLV-1 and present similarities in genetic sequence indicating that emergence of EBLV-1 is likely to be recent, potentially associated with the natural movement of bats from the near continent

Salmonella Typhi stool shedding by enteric fever patients and asymptomatic chronic carriers in an endemic urban setting

The burden of Salmonella Typhi shedding in stool and its contribution to transmission in endemic settings is unknown. During passive surveillance S. Typhi shedding was seen during convalescence in 332 bacteremic typhoid patients although none persisted at one-year follow-up. Anti-Vi-IgG titres were measured in age-stratified cohort of serosurveillance participants. Systematic stool sampling of 303 participants with high anti-Vi-IgG titres identified one asymptomatic carrier shedding. These findings suggest ongoing S. Typhi transmission in this setting is more likely to occur from acute convalescent cases although better approaches are needed to identify true chronic carriers in the community to enable typhoid elimination.

Prevalence of shifted Rayleigh filter for passive surveillance in underwater

PurposeFrom many decades, bearings-only tracking (BOT) is the interested problem for researchers. This utilises nonlinear filtering methods for state estimation as there is only information about the target, i.e. bearing is a nonlinear measurement. The measurement bearing is tangentially related to the target state vector. There are many nonlinear filtering algorithms developed so far in the literature.Design/methodology/approachIn this research work, the recently developed nonlinear filtering algorithm, i.e. shifted Rayleigh filter (SRF), is applied to BOT.FindingsThe SRF is tested for two-dimensional BOT against various scenarios. The simulation results emphasise that the SRF performs well when compared to the standard nonlinear filtering algorithm, unscented Kalman filter (UKF).Originality/valueSRF utilises the nonlinearities present in the bearing measurement through the use of moment matching. The SRF is able to produce the solution in highly noisy environment, long ranges and high dimension tracking.