Rodney E. Rohde

Bat-associated rabies virus in Skunks.

Rabies was undetected in terrestrial wildlife of northern Arizona until 2001, when rabies was diagnosed in 19 rabid skunks in Flagstaff. Laboratory analyses showed causative rabies viruses associated with bats, which indicated cross-species transmission of unprecedented magnitude. Public health infrastructure must be maintained to address emerging zoonotic diseases.

Molecular epidemiology of rabies epizootics in Texas

BACKGROUND Texas is in the midst of two independent epizootics of rabies, involving coyotes (Canis latrans) and domestic dogs (Canis familiaris) in southern Texas and grey foxes (Urocyon cinereoargenteus) in west central Texas. The domestic dog/coyote (DDC) and grey for (TF) rabies virus variants cannot be differentiated by antigenic typing with currently available monoclonal antibodies. These two variants also cannot be distinguished from a third variant, Sonora dog (SD) rabies, that is not enzootic in Texas, but occasionally occurs in animals along the western border with Mexico. OBJECTIVES To determine a method for the differentiation of the DDC. TF and SD variants, which is essential for epidemiologic monitoring of the Oral Rabies Vaccination Program (ORVP), a program instituted to control rabies in coyotes and grey foxes in Texas. STUDY DESIGN Primers complementary to nucleoprotein sequence of either the DDC or TF rabies virus permit specific reverse transcription and amplification by polymerase chain reaction. In addition, general primers, which recognize a broad range of rabies variants, used in conjunction with a restriction digest for the differentiation of DDC, TF of SD rabies virus were investigated. RESULTS AND CONCLUSIONS Of 122 specimens tested with specific primers. 111 (91%) were specifically identified as either DDC (33 samples) or TF (78 samples). Overly stringent conditions, enzyme inhibitors, or limiting RNA may account for the 11 non-amplifications. Amplification of RNA under less stringent conditions, with primers recognizing a broad range of rabies variants followed by digestion with either restriction enzyme Desulfovibrio desulfuricans I (Dde I) or Haemophilus influenzae Rf. (HinfI), was used to identify the 11 isolates that did not amplify with specific primers (6 DDC, 4 TF and 1 SD). In addition to these 11 isolates, the less stringent method of amplification, followed by enzyme digestion has identified a total of 125 additional specimens (26 DDC, 94 TF and 5 SD) that were not tested by variant-specific amplification. These data provide a means to track the spread of the different rabies virus variants and allow the ORVP to plan its vaccine disbursement by defining the two epizootic boundaries.

Effect of Bacteriophage Infection in Combination with Tobramycin on the Emergence of Resistance in Escherichia coli and Pseudomonas aeruginosa Biofilms

Bacteriophage infection and antibiotics used individually to reduce biofilm mass often result in the emergence of significant levels of phage and antibiotic resistant cells. In contrast, combination therapy in Escherichia coli biofilms employing T4 phage and tobramycin resulted in greater than 99% and 39% reduction in antibiotic and phage resistant cells, respectively. In P. aeruginosa biofilms, combination therapy resulted in a 60% and 99% reduction in antibiotic and PB-1 phage resistant cells, respectively. Although the combined treatment resulted in greater reduction of E. coli CFUs compared to the use of antibiotic alone, infection of P. aeruginosa biofilms with PB-1 in the presence of tobramycin was only as effective in the reduction of CFUs as the use of antibiotic alone. The study demonstrated phage infection in combination with tobramycin can significantly reduce the emergence of antibiotic and phage resistant cells in both E. coli and P. aeruginosa biofilms, however, a reduction in biomass was dependent on the phage-host system.

Bat rabies, Texas, 1996-2000.

Bats submitted to the Texas Department of Health (1996–2000) were speciated and tested for rabies virus antigen by direct immunofluorescence microscopy. Antigenic analysis of rabies virus–positive specimens was performed with monoclonal antibodies against the nucleoprotein of the virus; atypical or unexpected results were confirmed by genetic analysis of nucleoprotein sequence.

Epidemiology of rabies in skunks in Texas.

OBJECTIVE To obtain epidemiologic information on rabies in skunks in Texas. DESIGN Epidemiologic study. SAMPLE POPULATION Reports of skunks that had been submitted for rabies testing in Texas from 1953 through 2007. PROCEDURES Reports were reviewed to obtain information on seasonality of rabies in skunks, seasonality of human and domestic animal exposure to rabid skunks, commonly reported clinical signs of rabies in skunks, domestic animals frequently exposed to rabid skunks, common scenarios for exposure of domestic animals to rabid skunks, disposition of domestic animals exposed to rabid skunks, age and gender of humans exposed to rabid skunks, and usual routes of exposure of humans to rabid skunks. RESULTS On a yearly basis, the number of rabid skunks peaked in 1961, 1979, and 2001. On a monthly basis, the number of rabid skunks peaked in March and April. Over the study period, the percentage of rabid skunks from urban areas increased and the percentage from rural areas decreased. Striped skunks were the most common species. Dogs and cats were the domestic animals most frequently exposed to rabid skunks. On average, the highest numbers of humans exposed to rabid skunks were between 36 and 50 years old. Most humans were exposed through means other than a bite. Typical behaviors of rabid skunks were entering a dog pen, appearing outside during daytime, and attacking pets. CONCLUSIONS AND CLINICAL RELEVANCE Information on the epidemiology of rabies in skunks may be useful in planning and implementing local, state, and national rabies control and prevention campaigns.

Epidemiology of rabies in bats in Texas (2001–2010)

OBJECTIVE To obtain epidemiological information on rabies in bats in Texas. DESIGN Epidemiological study. SAMPLE Laboratory reports of bats that had been submitted for rabies testing in Texas from 2001 through 2010. PROCEDURES Laboratory reports were reviewed to obtain information on seasonality of rabies in bats; distribution, species, and rabies virus variants of rabid bats; and human and domestic animal exposures to rabid bats. RESULTS The number of rabid bats during the first 5 years of the study period remained static until a > 2-fold increase in 2006; during the subsequent 4 years, the annual number of rabid bats remained at this higher level, including a peak in 2008. The highest proportions of rabid bats were seen in late summer and early fall. The Brazilian free-tailed bat (Tadarida brasiliensis) was the most often affected species. Additionally, the rabies virus variant associated with the Brazilian free-tailed bat was the most prevalent. The percentage of rabid bats from urban areas was greater than that from rural areas. Dogs and cats were the domestic animals most frequently exposed to rabid bats. Most humans exposed to rabid bats did not report a known bite or scratch. The highest numbers of humans exposed to rabid bats were males between 11 to 15 years old. CONCLUSIONS AND CLINICAL RELEVANCE Information on the epidemiology of rabies in bats and the epidemiology of exposures to rabid bats may be useful in planning and implementing local, state, and national rabies control and prevention campaigns and in encouraging rabies vaccination of domestic animals.

MRSA model of learning and adaptation: a qualitative study among the general public

BackgroundMore people in the US now die from Methicillin Resistant Staphylococcus aureus (MRSA) infections than from HIV/AIDS. Often acquired in healthcare facilities or during healthcare procedures, the extremely high incidence of MRSA infections and the dangerously low levels of literacy regarding antibiotic resistance in the general public are on a collision course. Traditional medical approaches to infection control and the conventional attitude healthcare practitioners adopt toward public education are no longer adequate to avoid this collision. This study helps us understand how people acquire and process new information and then adapt behaviours based on learning.MethodsUsing constructivist theory, semi-structured face-to-face and phone interviews were conducted to gather pertinent data. This allowed participants to tell their stories so their experiences could deepen our understanding of this crucial health issue. Interview transcripts were analysed using grounded theory and sensitizing concepts.ResultsOur findings were classified into two main categories, each of which in turn included three subthemes. First, in the category of Learning, we identified how individuals used their Experiences with MRSA, to answer the questions: What was learned? and, How did learning occur? The second category, Adaptation gave us insights into Self-reliance, Reliance on others, and Reflections on the MRSA journey.ConclusionsThis study underscores the critical importance of educational programs for patients, and improved continuing education for healthcare providers. Five specific results of this study can reduce the vacuum that currently exists between the knowledge and information available to healthcare professionals, and how that information is conveyed to the public. These points include: 1) a common model of MRSA learning and adaptation; 2) the self-directed nature of adult learning; 3) the focus on general MRSA information, care and prevention, and antibiotic resistance; 4) the interconnected nature of adaptation; and, 5) the need for a consistent step by step plan to deal with MRSA provided at the time of diagnosis.

Methicillin-Resistant Staphylococcus aureus Nasal Carriage Rate in Texas County Jail Inmates

Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a health issue in corrections. The Texas Department of State Health Services (DSHS) partnered with an urban jail to investigate risk factors for MRSA carriage. This study assessed nasal carriage rate and strainrelatedness of MRSA among recently booked inmates. Of 403 inmates, 115 (28.5%) carried S. aureus; 18 were MRSA-positive (4.5%). Pulsed field gel electrophoresis identified 10 MRSA strains. Previous health care exposures and history of skin infection were more strongly associated with carriage risk than previous correctional facility exposure, although none of these exposures was statistically significant after adjustment. Our data suggest that MRSA is endemic in persons coming into correctional facilities. Correctional health care workers should be prepared to treat MRSA infections that arise from exposures before incarceration.

Typing of rabies virus isolates by DNA enzyme immunoassay.

BACKGROUND Alternatives to antigenic typing are needed for epidemiologic surveys of the rabies virus associated with translocated coyotes and foxes, especially in areas where a closely related rabies virus is transmitted by striped skunks. OBJECTIVES We developed and evaluated two enzyme based typing methods for rabies virus. The products of a reverse transcription-polymerase chain reaction (RT/PCR) of the nucleoprotein gene were hybridized to type specific probes and detected by enzyme assay after immobilization on microtiter plates. STUDY DESIGN We tested RT/PCR products of 27 rabies isolates by two different DNA enzyme immunoassays (DEIA) and evaluated the quality of the results from the corresponding nucleotide sequence of the samples. RESULTS Using a set of two probes, one of the DEIAs correctly identified 26/27 samples as variants of rabies virus associated with either skunks, foxes, or coyotes. The identity of one fox rabies sample was unresolved by this assay. The second DEIA correctly identified 24/27 samples as variants of rabies virus associated with either skunks, foxes, or coyotes. This assay did not resolve the identity of two fox rabies samples, and misidentified one fox rabies sample as a skunk rabies sample. CONCLUSIONS DEIA can be used for epidemiologic studies of variants of rabies virus associated with skunks, foxes, and coyotes. Both DEIA methods were effective when typing probes recognized changes at a minimum of two nucleotide positions between variants, but only one assay method was sufficiently stringent to detect a single base pair mismatch. The inherent mutability of RNA viruses must be considered when designing and evaluating typing methods.

Stress-induced change in serum BDNF is related to quantitative family history of alcohol use disorder and age at first alcohol use

ABSTRACT Previous research in animal models suggests that brain‐derived neurotrophic factor (BDNF) is involved in stress‐modulated alcohol consumption. However, relatively few studies have investigated this issue in humans, and results of existing studies have been heterogeneous. The primary aim of the current study was to examine the within‐subjects effect of acute stress (timed math plus cold pressor) on serum BDNF levels (&Dgr;BDNF: post‐ minus pre‐stress) in healthy social drinkers (N = 68, 20 male). A secondary aim was to explore which heritable and environmental factors in our limited sample might exert the greatest influences on &Dgr;BDNF. Importantly, presence versus absence of the BDNF Val66Met polymorphism (rs6265), which has often been discounted in studies of human serum BDNF, was included as a between‐subjects control variable in all statistical analyses. Our results indicated that acute stress decreased serum BDNF. Further, multiple regression analyses revealed that quantitative family history of alcohol use disorder (qFH) and age at first alcohol use together accounted for 15% of the variance in &Dgr;BDNF. Thus, the influences of qFH and age at first alcohol use may explain some of the heterogeneity that exists in previous studies of human serum BDNF. These results parallel findings in animal models and suggest that stress‐related changes in serum BDNF are influenced by both heritable (qFH) and environmental (early alcohol consumption) factors. HighlightsAcute stress reduced serum BDNF levels in healthy social drinkers.Family history and age at first drink accounted for 15% of the variance in &Dgr;BDNF.BDNF stress‐reactivity is influenced by both heritable and environmental factors.