Seroprevalence of Foot-and-Mouth Disease in Susceptible Wildlife in Israel

Foot and mouth disease (FMD) epidemics recur in Israel almost every year. Wild even-toed ungulates are seldom affected during these epidemics. The sero-prevalence of FMD in wild ungulates during 2000 and 2005-13 was estimated using anti non-structural proteins (NSP) ELISA. Overall, 209 samples were tested, comprising sera of 120 wild boar (Sus scrofa lybicus), 64 mountain gazelles (Gazella gazella gazella), six water buffaloes (Bubalus bubalis), and 19 Persian fallow deer (Dama dama mesopotamica). None of the tested animals presented clinical signs of FMD during blood collection. Sixteen samples (7.7% (95% confidence interval (CI95%) = 4.4 - 12.1%)) were found to be sero-positive. Fifteen out of 120 samples (12.5%) from wild boar were sero-positive, compared with only one out of 89 samples (1.1%) from all other species combined (Fisher's Exact test: p=0.003). Most of the positive samples obtained from wild boar (13/15 (86.7%)) were collected during 2007 and analysis was restricted to that year and species only. The sero-prevalence of FMD in this species during 2007 was estimated at 54.2% (CI95%=32.8 - 74.5%; n=24). A significant infection cluster, comprising nine sero-positive samples collected in three different locations, was identified in the north-eastern part of Israel. These findings indicate that wild boar were affected during the 2007 FMD epidemic, even though wild boar presenting FMD typical clinical signs were not observed during that year. The actual role of wild boar in the spread of FMD virus in this epidemic, however, could not be determined. The negligible sero-prevalence of FMD found for all other surveillance years indicates that ongoing circulation of FMD among wildlife in Israel is unlikely. It is concluded that while the role of wildlife species in the dynamics of FMD in Israel is usually limited, there might be occasions in which wildlife play a part in the spread of the virus

Estimation of the basic reproduction number for Streptococcus equi spp. equi outbreaks by meta-analysis of strangles outbreak reports

Background Streptococcus equi spp. equi (S. equi), the cause of strangles in horses, is considered a highly contagious pathogen affecting equines and the equine industry worldwide. Fundamental epidemiological characteristics of outbreaks, such as the basic reproduction number (R-0), are not well described. Objectives Estimate R-0 for S. equi in equine populations from outbreak data. Study design Systematic review and meta-analysis of published and unpublished data. Methods A literature search for outbreak reports was carried out. Depending on data available in the reports, the early epidemic growth rate or final attack rate (AR) approach was used to estimate the basic reproduction number for that outbreak. Other recorded outbreak characteristics were the type of housing (group vs. individual). An overall estimate for R-0 was computed by meta-analysis. Results Data from eight outbreaks were extracted from peer-reviewed publications. Data from two additional, non-published outbreaks was also included in the meta-analysis. A conservative estimate for R-0 was 2.2 (95% confidence interval [CI] 1.9-2.5). A less conservative estimate, including outbreaks with a 100% AR for which a lower limit R-0 was estimated, was 2.7 (95% CI 2.1-3.3). Main limitations Few papers describing longitudinal incidence data were found so most estimates were based on the outbreaks' final size. Several outbreaks had a 100% attack rate and could therefore only be included as a lower limit estimate in the meta-analysis. The reported result therefore may be an underestimation. Conclusions This estimate for R-0 for S. equi informs parameters for future mathematical modelling, quantifies desired preventive vaccine coverage and helps evaluate the effect of prevention strategies through future modelling studies

Estimation of the basic reproduction number for Streptococcus equi spp. equi outbreaks by meta-analysis of strangles outbreak reports

BACKGROUND: Streptococcus equi spp. equi (S. equi), the cause of strangles in horses, is considered a highly contagious pathogen affecting equines and the equine industry worldwide. Fundamental epidemiological characteristics of outbreaks, such as the basic reproduction number (R0 ), are not well described. OBJECTIVES: Estimate R0 for S. equi in equine populations from outbreak data. STUDY DESIGN: Systematic review and meta-analysis of published and unpublished data. METHODS: A literature search for outbreak reports was carried out. Depending on data available in the reports, the early epidemic growth rate or final attack rate (AR) approach was used to estimate the basic reproduction number for that outbreak. Other recorded outbreak characteristics were the type of housing (group vs. individual). An overall estimate for R0 was computed by meta-analysis. RESULTS: Data from eight outbreaks were extracted from peer-reviewed publications. Data from two additional, non-published outbreaks was also included in the meta-analysis. A conservative estimate for R0 was 2.2 (95% confidence interval [CI] 1.9-2.5). A less conservative estimate, including outbreaks with a 100% AR for which a lower limit R0 was estimated, was 2.7 (95% CI 2.1-3.3). MAIN LIMITATIONS: Few papers describing longitudinal incidence data were found so most estimates were based on the outbreaks' final size. Several outbreaks had a 100% attack rate and could therefore only be included as a lower limit estimate in the meta-analysis. The reported result therefore may be an underestimation. CONCLUSIONS: This estimate for R0 for S. equi informs parameters for future mathematical modelling, quantifies desired preventive vaccine coverage and helps evaluate the effect of prevention strategies through future modelling studies

Experimental and field investigations of exposure, replication and transmission of SARS-CoV-2 in pigs in the Netherlands

In order to assess the risk of SARS-CoV-2 infection, transmission and reservoir development in swine, we combined results of an experimental and two observational studies. First, intranasal and intratracheal challenge of eight pigs did not result in infection, based on clinical signs and PCR on swab and lung tissue samples. Two serum samples returned a low positive result in virus neutralization, in line with findings in other infection experiments in pigs. Next, a retrospective observational study was performed in the Netherlands in the spring of 2020. Serum samples (N =417) obtained at slaughter from 17 farms located in a region with a high human case incidence in the first wave of the pandemic. Samples were tested with protein micro array, plaque reduction neutralization test and receptor-binding-domain ELISA. None of the serum samples was positive in all three assays, although six samples from one farm returned a low positive result in PRNT (titers 40-80). Therefore we conclude that serological evidence for large scale transmission was not observed. Finally, an outbreak of respiratory disease in pigs on one farm, coinciding with recent exposure to SARS-CoV-2 infected animal caretakers, was investigated. Tonsil swabs and paired serum samples were tested. No evidence for infection with SARS-CoV-2 was found. In conclusion, Although in both the experimental and the observational study few samples returned low antibody titer results in PRNT infection with SARS-CoV-2 was not confirmed. It was concluded that sporadic infections in the field cannot be excluded, but large-scale SARS-CoV-2 transmission among pigs is unlikely.info:eu-repo/semantics/publishedVersio

Globetrotting strangles: the unbridled national and international transmission of Streptococcus equi between horses.

The equine disease strangles, which is characterized by the formation of abscesses in the lymph nodes of the head and neck, is one of the most frequently diagnosed infectious diseases of horses around the world. The causal agent, Streptococcus equi subspecies equi, establishes a persistent infection in approximately 10 % of animals that recover from the acute disease. Such 'carrier' animals appear healthy and are rarely identified during routine veterinary examinations pre-purchase or transit, but can transmit S. equi to naïve animals initiating new episodes of disease. Here, we report the analysis and visualization of phylogenomic and epidemiological data for 670 isolates of S. equi recovered from 19 different countries using a new core-genome multilocus sequence typing (cgMLST) web bioresource. Genetic relationships among all 670 S. equi isolates were determined at high resolution, revealing national and international transmission events that drive this endemic disease in horse populations throughout the world. Our data argue for the recognition of the international importance of strangles by the Office International des Épizooties to highlight the health, welfare and economic cost of this disease. The Pathogenwatch cgMLST web bioresource described herein is available for tailored genomic analysis of populations of S. equi and its close relative S. equi subspecies zooepidemicus that are recovered from horses and other animals, including humans, throughout the world. This article contains data hosted by Microreact

Detection and control of lentiviral infections in sheep and goats

The quality of the laboratory diagnosis for Small Ruminant Lentivirus (SRLV) infections, particularly their early detection in sheep and goats is of utmost importance to their control in the host animal population. However, the reliability of serological as well as molecular biological assays is seriously hampered by the immense heterogeneity of the viral genomes. Consequences of sub-optimal laboratory diagnosis include unnoticed transmission of the disease - complicating international trade- and decreasing support for voluntary control programs. This thesis-based review focuses on technically improving the laboratory detection of SRLV and on reducing its costs, starting with an overview relevant to the biology and control of SRLV infections. The quality of antibody testing was thoroughly evaluated and secured, and subsequent efforts to reduce costs proved successful. In addition, a molecular biological tool for the detection of the viral genome was developed in view of the intrinsic limitation of antibody detection, i.e. slow or no antibody formation. Because the collection of the usual sample for testing, blood, which is legally restricted to veterinarians, adds considerably to the testing costs, the possibilities for using less costly samples were evaluated. After some adaptation of the testing protocols, milk (and plasma) was shown to be a reliable substitute of serum. Moreover, the feasibility of testing bulk milk was studied, since this could offer a new and very cost effective way of monitoring for infection at the flock level