Methicillin Resistant Staphylococcus aureus (MRSA) in market age pigs on-farm, at slaughter and retail pork

This study was conducted to determine the occurrence and prevalence of methicillin resistant Staphylococcus aureus (MRSA) in finishing pigs on-farm, at lairage and assess the likelihood of carriage at slaughter and retail levels. A cross-sectional study targeting ten cohorts of commercial swine farms was conducted for carriage of MRSA

Detection and distribution of a Rocky Mountain spotted fever group Rickettsia sp. and Babesia microti from Ixodes scapularis in Indiana counties

In Indiana, Ixodes scapularis is an important tick in public health because it feeds on a variety of hosts including humans, and transmits Borrelia burgdorferi (Lyme disease), Anaplasma phagocytophilum (human granulocytic ehrlichiosis), and Babesia microti (babesiosis). Symbiotic, non-pathogenic Rickettsia found in Ixodes scapularis may play a role in excluding pathogenic species of Rickettsia from being transovarially transmitted. In order to investigate this idea further in Indiana, a total of 378 adult I. scapularis from 4 different counties (Jasper, Pulaski, Newton and Starke) were tested by polymerase chain reaction analysis (PCR) for the presence of Rickettsia sp. Four positive samples from the PCR (using Rocky Mountain spotted fever group specific primers to target the rOmpA gene; Rr190.70p and RH 90.602n) reactions were sequenced to verify identity. These four samples matched closest to the reference number AB002268 from GenBank which describes, I. scapularis endosymbiont DNA for rOmpA. A total of 62 engorged females were tested; 53 (85.5%) harbored the rickettsial symbiont. A total of 41 questing females were tested; 33 (80.5%) were positive. Of the 249 males tested, 14 (5.6%) were positive. A restriction digestion on some of the positive samples revealed that the 1 scapularis symbiont was different from R. montana and R. rickettsii. The second goal of this study was to identify the presence of B. microti. In I. scapularis ticks, this would be the first time this pathogen was identified in Indiana. To accomplish this goal 106, ticks were tested using the primers Babl and Bab4, which target the 18S rRNA gene specific for B. microti. Three tick samples were found to harbor B. microti as determined by sequencing. However, sequencing of amplification band in the negative control also yielded B. microti. Thus, the presence of B. microti in Indiana ticks could not be confirmed. A negative control was also sequenced and was identified as Babesia microti indicating that there was a contamination so it is not possible to conclude that B. microti was found in Indiana ticks.Thesis (M.S.)Department of Physiology and Health Scienc

Detection and distribution of a Rocky Mountain spotted fever group Rickettsia sp. and Babesia microti from Ixodes scapularis in Indiana counties

In Indiana, Ixodes scapularis is an important tick in public health because it feeds on a variety of hosts including humans, and transmits Borrelia burgdorferi (Lyme disease), Anaplasma phagocytophilum (human granulocytic ehrlichiosis), and Babesia microti (babesiosis). Symbiotic, non-pathogenic Rickettsia found in Ixodes scapularis may play a role in excluding pathogenic species of Rickettsia from being transovarially transmitted. In order to investigate this idea further in Indiana, a total of 378 adult I. scapularis from 4 different counties (Jasper, Pulaski, Newton and Starke) were tested by polymerase chain reaction analysis (PCR) for the presence of Rickettsia sp. Four positive samples from the PCR (using Rocky Mountain spotted fever group specific primers to target the rOmpA gene; Rr190.70p and RH 90.602n) reactions were sequenced to verify identity. These four samples matched closest to the reference number AB002268 from GenBank which describes, I. scapularis endosymbiont DNA for rOmpA. A total of 62 engorged females were tested; 53 (85.5%) harbored the rickettsial symbiont. A total of 41 questing females were tested; 33 (80.5%) were positive. Of the 249 males tested, 14 (5.6%) were positive. A restriction digestion on some of the positive samples revealed that the 1 scapularis symbiont was different from R. montana and R. rickettsii. The second goal of this study was to identify the presence of B. microti. In I. scapularis ticks, this would be the first time this pathogen was identified in Indiana. To accomplish this goal 106, ticks were tested using the primers Babl and Bab4, which target the 18S rRNA gene specific for B. microti. Three tick samples were found to harbor B. microti as determined by sequencing. However, sequencing of amplification band in the negative control also yielded B. microti. Thus, the presence of B. microti in Indiana ticks could not be confirmed. A negative control was also sequenced and was identified as Babesia microti indicating that there was a contamination so it is not possible to conclude that B. microti was found in Indiana ticks.Department of Physiology and Health ScienceThesis (M.S.

Methicillin-resistant Staphylococcus aureus in pigs and farm workers on conventional and antibiotic-free swine farms in the USA.

Much uncertainty remains about the origin and public health implications of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA). This study aimed to investigate the occurrence and prevalence of MRSA in general and LA-MRSA in particular in pigs and farm workers in five states. We collected nasal swabs from pigs and farm workers at 45 swine herds (21 antibiotic-free herds; 24 conventional herds) in Illinois, Iowa, Minnesota, North Carolina and Ohio. MRSA was isolated from 50 of 1085 pigs (4.6%) and 31 of 148 (20.9%) of farm workers. MRSA-positive pigs and people were clustered in four conventional swine farms in Iowa and Illinois. Based on genotyping, spa type t034, a common livestock associated variant, was predominant among both human and swine isolates. These results confirm the presence of LA-MRSA in pigs and swine farm workers in the USA, but the prevalence found is relatively low compared with European studies

Demographic and occupational characteristics of participating workers from farms with MRSA-positive swine.

*<p>Not all categories sum to the column total because of missing data for some participants.</p>1<p>p-values are based on Fisher's exact test (for categorical data) or the Wilcoxon rank sum test (for continuous data).</p>2<p>Interquartile range (IQR), represented by the values of the 25^th and 75^th percentiles.</p

Distribution of <i>spa</i> types among human and swine isolates of MRSA.

*<p>Ridom <i>spa</i> type.</p>#<p><i>spa</i> types of ST398 lineage.</p

Mosquito Species (Diptera: Culicidae) and the Transmission of Ross River Virus in Brisbane, Australia

This study aimed to identify the major mosquito vectors of Ross River virus (family Togaviridae, genus Alphavirus, RRV) and to explore the threshold of mosquito abundance necessary for RRV transmission in Brisbane, Australia. Data on the monthly counts of RRV cases by statistical local areas from the Queensland Health and the monthly mosquito abundance in Brisbane between November 1998 and December 2001 from the Brisbane City Council were used to assess the pairwise relationship between mosquito abundance and the incidence of RRV disease over a range of time lags using cross-correlations. We used time series Poisson regression models to identify major mosquito species associated with incidence of RRV after adjusting for overdispersion, maximum temperature, autocorrelation, and seasonality. Our results show that Aedes vigilax (Skuse) (relative risk [RR] = 1.32; 95% CI = 1.01-1.74 per 100 mosquitoes per trap) and Culex annulirostris (Skuse) (RR = 1.14, 95% CI = 1.04-1.24 per 100 mosquitoes per trap) were most strongly associated with RRV transmission at a lag of 1 mo. Classification and regression tree (CART) analyses indicate that the occurrence of RRV was associated with an average monthly mosquito abundance ofAedes vigilax above 72 and Cx. annulirostris above 52. The validation analyses indicate that the crude agreement between predicted values and actual observations was 76% (sensitivity, 61%; specificity, 80%). The results may have applications as a decision support tool in planning disease control and risk-management programs