Bovine Respiratory Syncytial Virus Infection in McNay Farm Calves

Clinical respiratory disease occurs almost every year in fall calves in the McNay Farm herd. Diagnostic procedures have implicated Haemophilus somnus (H. somnus) and bovine respiratory syncyial virus (BRSV) as the infectious agents primarily associated with this disease. Therefore, the 1995 calves were closely monitored after weaning and during the course of a respiratory disease. Serologic evidence indicated the involvement of the same two agents in the pathogenesis of the disease. Also, experimental evidence suggested a role for a preexisting immediate hypersensitivity to H. somnus and the development of this type of response to BRSV. We theorize that the pathogenesis of the clinical disease involved infection with H. somnus, establishment of immediate hypersensitivity in the lungs, viral infection with associated pathologic lesions, and viral exacerbation of the immediate hypersensitivity reaction with resultant clinical signs and tissue damage.

Prebreeding Immunization of Beef Cows

A number of infectious agents are potential threats to the fetus of a pregnant cow and may result in abortion. These agents include Leptospira sp., Campylobacter fetus and viruses such as infectious bovine rhinotracheitis (IBR) and bovine virus diarrhea (BVD). Maintenance in the cow of a high level of immunity to these agents during pregnancy can insure protection of the fetus. In particular, vaccines against BVD and IBR viruses can establish protective immunity throughout gestation. An appropriate vaccination regimen prior to breeding is required to establish this protective immunity. This can be achieved with a single dose of certain modified live virus vaccines, but those vaccines must be administered at least 30 days prior to breeding to avoid interference with conception. We have evaluated an oil-adjuvanted inactivated virus vaccine in cattle with differing immunological histories. Two doses of the vaccine administered 30 days apart to serologically negative animals induced appreciable levels of BVD and IBR anti-viral antibodies with persisting titers throughout gestation. In other experiments a single dose of the vaccine was administered to: (1) animals given two doses of the vaccine several months earlier, (2) animals previously vaccinated with other inactivated virus vaccines, or (3) animals previously vaccinated with modified live virus vaccine. The vaccine consistently induced marked anamnestic responses in these animals. Not only did mean titers rise, but a vast majority of individual animals responded. This contrasts with efforts to boost titers with modified live virus vaccines where the effect may be erratic among animals. The safety and efficacy of selected inactivated viral vaccines argues for their use in prebreeding immunization of beef cows.

Investigation of potential causes for the development of porcine ear necrosis: different study designs--comparable results?

During the last years two studies for the investigation of the etiology of porcine ear necrosis were carried out at the Clinic for Swine of the University of Veterinary Medicine Vienna. In study 1, parameters, which are discussed in this context, were collected by veterinary practitioners by completing specially designed questionnaires in farms with symptoms of the porcine ear necrosis syndrome. In study 2, samples of piglets and feed were collected for laboratory analysis of the most important infectious agents as well as mycotoxins. In the present manuscript, the results of both projects were compared. Even if the selection criteria of both studies differed, the affected age class was comparable (5.5 to ten weeks of life in study 1 and six to ten weeks of life in study 2). The herd-specific prevalence of the porcine ear necrosis syndrome varied considerably with percentages between 2 and 10, respectively, to 100%. The evaluation of questionnaires in study 1 showed that 51% of the farms had problems with cannibalism. Particles of plant material, which were frequently seen on the histologic slides of study 2, could have got into the tissue by chewing the ears of the pen mates or cannibalism. Whereas in study 1 the negative effect of parameters as high pig density, suboptimal climate, missing enrichment material and bad quality of feed and water were considered, in study 2 all these factors were checked at sample collection and ruled out as precursor for cannibalism. In both studies bacterial agents proved to be a crucial co-factor for the expansion of the necroses to deeper tissue layers, whereas viral pathogens were classified less important. In both projects it was not possible to estimate the direct impact of infectious agents and mycotoxins as direct trigger of the necroses as well as their participation as co-factors or precursor in the sense of an immunosuppression or previous damage of blood vessels or tissue.

Multiple infections of rodents with zoonotic pathogens in Austria

Rodents are important reservoirs for a large number of zoonotic pathogens. We examined the occurrence of 11 viral, bacterial, and parasitic agents in rodent populations in Austria, including three different hantaviruses, lymphocytic choriomeningitis virus, orthopox virus, Leptospira spp., Borrelia spp., Rickettsia spp., Bartonella spp., Coxiella burnetii, and Toxoplasma gondii. In 2008, 110 rodents of four species (40 Clethrionomys glareolus, 29 Apodemus flavicollis, 26 Apodemus sylvaticus, and 15 Microtus arvalis) were trapped at two rural sites in Lower Austria. Chest cavity fluid and samples of lung, spleen, kidney, liver, brain, and ear pinna skin were collected. We screened selected tissue samples for hantaviruses, lymphocytic choriomeningitis virus, orthopox viruses, Leptospira, Borrelia, Rickettsia, Bartonella spp., C. burnetii, and T. gondii by RT-PCR/PCR and detected nucleic acids of Tula hantavirus, Leptospira spp., Borrelia afzelii, Rickettsia spp., and different Bartonella species. Serological investigations were performed for hantaviruses, lymphocytic choriomeningitis virus, orthopox viruses, and Rickettsia spp. Here, Dobrava-Belgrade hantavirus-, Tula hantavirus-, lymphocytic choriomeningitis virus-, orthopox virus-, and rickettsia-specific antibodies were demonstrated. Puumala hantavirus, C. burnetii, and T. gondii were neither detected by RT-PCR/PCR nor by serological methods. In addition, multiple infections with up to three pathogens were shown in nine animals of three rodent species from different trapping sites. In conclusion, these results show that rodents in Austria may host multiple zoonotic pathogens. Our observation raises important questions regarding the interactions of different pathogens in the host, the countermeasures of the host's immune system, the impact of the host–pathogen interaction on the fitness of the host, and the spread of infectious agents among wild rodents and from those to other animals or humans.

Tumor-induced inflammation alters neutrophil phenotype and disease progression

Neutrophils are essential to combat infectious agents but contribute to collateral inflammatory damage. Likewise, neutrophils can kill cancer cells and have been shown to promote malignant growth and metastasis through immunosuppressive functions. Two articles in a recent issue of Nature reveal new mechanisms by which tumors induce changes in neutrophil phenotype through production of inflammatory cytokines. Although the two studies report different outcomes on the effects of neutrophils on tumor growth and metastasis, they delineate novel molecular pathways influencing neutrophil phenotype that may provide new approaches to harnessing neutrophil functions in the treatment of cancer.

Interferon-gamma and interleukin-4 mRNA expression by peripheral blood mononuclear cells from pregnant and non-pregnant cattle seropositive for bovine viral diarrhea virus

The acceptance of the fetal allograft by pregnant women and mice seems to be associated with a shift from a Th 1 dominated to a Th 2 dominated immune response to certain infectious agents. The goal of this study was to examine cytokine expression in peripheral blood mononuclear cells (PBMCs) from cattle immune to bovine viral diarrhea virus (BVDV) to determine whether pregnancy also has an influence on the type of immune response in this species. Forty-six heifers and cows between 14 months and 13 years of age were included in this study. Twenty-four were seropositive and 22 seronegative for BVDV. Eleven of the seropositive animals and 11 of the seronegative animals were in the eighth month of gestation, the remaining animals were virgin heifers. PBMC from these animals were analyzed for Interferon (IFN)-gamma and Interleukin (IL)-4 mRNA expression by real-time RT-PCR after stimulation with a non-cytopathic strain of BVDV. Additionally, an ELISA was performed to measure IFN-gamma in the supernatants of stimulated cell cultures. In BVDV seropositive animals, IFN-gamma mRNA levels were significantly higher than in BVDV seronegative animals and there was a significant positive correlation between the changes in IFN-gamma and IL-4 mRNA expression. There was, however, no significant difference in IFN-gamma and IL-4 mRNA levels between pregnant and non-pregnant animals. These results are inconsistent with BVDV inducing a Th1 or Th2 biased immune response. Furthermore, a shift in the cytokine pattern during bovine pregnancy was not evident.

Texas dental hygiene/dietitian occupational health study

Occupational asthma is the most common form of reported occupational respiratory disease in many industrialized countries. Recent studies show that environmental exposures account for up to 40% of the cases of asthma and that 2% to 15% of all cases of asthma are attributable to occupational exposures. In the dental workplace, dental hygienists are exposed to hazardous substances. Among these hazards are respiratory sensitizers, irritants and infectious agents. A cross-sectional study of Texas dental hygienists was conducted to assess the prevalence of occupational asthma. Registered dietitians were surveyed as a comparison group, because this group is similar in demographic makeup to dental hygienists, but conducts no clinical treatment with associated hazardous exposures. Neither the questionnaire survey nor the cover letter revealed the focus of this investigation. Three hundred and thirty five dental hygienists licensed to practice in the state of Texas as of January 1, 1999, and 320 dietitians that are also licensed by the state of Texas were randomly selected. (Abstract shortened by UMI.)^

Using the results of routine laboratory workplace surveillance activities to assess compliance with recommended biosafety guidelines

The biological safety profession has historically functioned within an environment based on recommended practices rather than regulations, so summary data on compliance or noncompliance with recommended practices is largely absent from the professional literature. The absence of safety performance outcome data is unfortunate since the concept of biosafety containment is based on a combination of facility based controls and workplace practices, and persistent failures in either type of controls could ultimately result in injury or death. In addition, the number of laboratories requiring biosafety containment is likely to grow significantly in the coming years in the wake of the terrorist events of 2001. In this study, the outcomes of 768 biosafety level 2 (BSL-2) safety surveys were analyzed for commonalities and trends. Items of non-compliance noted were classified as facility related or practice related. The most frequent item of noncompliance encountered was the failure to re-certify biosafety cabinetry. Not surprisingly, the preponderance of the other frequent items of non-compliance encountered were practice related, such as general housekeeping orderly, changes in compliance levels, as well as establish trends in the elements of items of non-compliance during the sequential survey period. The findings described in this study are significant because, for the first time, the outcomes of compliance with recommended biosafety practices can be characterized and thus used as the basis for focused interventions. Since biosafety is heavily reliant on adherence to specific safety practices, the ability to focus interventions on objectively identified practice-related items of non-compliance can assist in the reduction of worker risk in this area experiencing tremendous growth. The information described is also of heighten importance given the number of workplaces expected to involve potentially infectious agents in the coming years. ^

Diffusely adherent Escherichia coli (DAEC) as a cause of acute diarrhea

Acute diarrhea is the most common medical problem in the developing countries. Infectious agents are responsible for a majority of cases of acute diarrhea. Knowing the cause of acute diarrhea is important to developing plans for disease prevention, control and therapy. Acute diarrhea is caused by many viruses, bacteria and parasites. ^ Travelers to developing countries of the world commonly develop diarrhea as a result of eating contaminated food or drinking contaminated water. About 30-50% of travelers who travel from industrialized countries like United States to the developing countries are at risk of developing diarrhea. High risk areas for travelers' diarrhea are Mexico, Latin America and Southeast Asia. Public restaurants are the common sites for exposure to this type of food-borne infectious disease in travelers. Food becomes contaminated when they are handled by people with fecal content on their hands. ^ The importance of Diffusely Adherent Escherichia Coli (DAEC) in travelers to these areas has not been well studied. Some of the studies looking at DAEC have shown the organism to be present in children without symptoms. Other studies have shown a relationship between DAEC infection and presence of symptoms. I have selected this topic because the patho-physiological processes in DAEC infection that allow intestinal and extra-intestinal infections to develop are not fully understood. DAEC related acute diarrhea is a relatively new topic of public health significance. There is a limited number of studies regarding the virulence and pathogenic mechanisms of DAEC. The presumed virulence factor of the organism is diffuse attachment to the intestinal lining of the infected host. However more research needs to be done to identify the pathogenic mechanisms and virulence factors associated with DAEC infection for better treatment planning and diarrhea prevention. ^

Associations between vaccination and childhood cancers in Texas counties

Background. In Dr. Mel Greaves "delayed-infection hypothesis," postponed exposure to common infections increases the likelihood of childhood cancer. Hygienic advancements in developed countries have reduced children's exposure to pathogens and children encounter common infectious agents at an older age with an immune system unable to deal with the foreign antigens. Vaccinations may be considered to be simulated infections as they prompt an antigenic response by the immune system. Vaccinations may regulate the risk of childhood cancer by modulating the immune system. The aim of the study was to determine if children born in Texas counties with higher levels of vaccination coverage were at a reduced risk for childhood cancer.^ Methods. We conducted a case-control study to examine the risk of childhood cancers, specifically leukemia, brain tumors, and non-Hodgkin lymphoma, in relation to vaccination rates in Texas counties. We utilized a multilevel mixed-effects regression model of the individual data from the Texas Cancer Registry (TCR) with group-level exposure data (i.e., the county- and public health region-level vaccination rates).^ Results. Utilizing county-level vaccination rates and controlling for child's sex, birth year, ethnicity, birth weight, and mother's age at child's birth the hepatitis B vaccine revealed negative associations with developing all cancer types (OR = 0.81, 95% CI: 0.67–0.98) and acute lymphoblastic leukemia (ALL) (OR = 0.63, 95% CI: 0.46–0.88). The decreased risk for ALL was also evident for the inactivated polio vaccine (IPV) (OR = 0.67, 95% CI: 0.49–0.92) and 4-3-1-3-3 vaccination series (OR = 0.62, 95% CI: 0.44-0.87). Using public health region vaccine coverage levels, an inverse association between the Haemophilus influenzae type b (Hib) vaccine and ALL (OR: 0.58; 95% CI: 0.42–0.82) was present. Conversely, the measles, mumps, and rubella (MMR) vaccine resulted in a positive association with developing non-Hodgkin lymphoma (OR = 2.81, 95% CI: 1.27–6.22). ^

Adenovirus-36 infection and obesity related hormones in children

Obesity has a complex, multi-factorial etiology. Infectious agents have recently emerged as a possible contributor to the current obesity epidemic. Seven viruses have demonstrated an association with obesity in animals; however, Adenovirus-36 (Ad-36) is the only known virus associated with obesity in humans. The primary aim of this research was to determine the association between Ad-36 infection and the expression of obesity related hormones in children. Additionally, this study proposed to compare the mean three year change in the level of obesity related hormones between Ad-36 positive and negative children. This study utilized pilot data collected from 98 children at baseline and year three of the Project Heartbeat! cohort. Fasting serum samples were analyzed for the concentration of adiponectin, insulin and leptin. The crude analysis uncovered Ad-36 positive children had significantly lower mean concentrations of insulin (p=0.039) and leptin (p=0.038) at baseline compared to Ad-36 negative children. The results of the adjusted analysis indicated the leptin association with Ad-36 infection at baseline was statistically significant even after controlling for age, sex, ethnicity, and BMI percentile. The longitudinal evaluation revealed individuals with a history of Ad-36 infection experienced a larger mean decrease in adiponectin, a larger mean increase in leptin, and a smaller mean increase in insulin levels over a three year period compared to individuals without a history of infection. These results suggest Ad-36 infection may produce changes in hormone expression. The only statistically significant findings in the crude and adjusted longitudinal analysis occurred at baseline when the children were younger, suggesting physical changes that occur during sexual maturation may mask or enhance Ad-36 induced changes in hormone expression. Furthermore, the longitudinal analysis revealed the duration and course of Ad-36 infection may influence changes in the expression of obesity-related hormones. Taken together, the results of this pilot study are suggestive of an association between Ad-36 infection and the expression of obesity-related hormones.^

Evaluation of elevator shafts as a pathway for fungal spores and particles to enter a hospital housing immuno-compromised patients

Background. It is estimated that hospitals spend between 28 and 33 billion dollars per year as a result of hospital-acquired infections. (Scott, 2009) The costs continue to rise despite the guidance and controls provided by hospital infection control staff to reduce patient exposures to fungal spores and other infectious agents. With all processes and controls in place, the vented elevator shaft represents an unprotected opening from the top of the building to the lower floors. The hypothesis for this prospective study is that there is a positive correlation between the number of Penicillium/Aspergillus-like spores, Cladosporium, ascospores, basidiospores in spores/m3 as individual spore categories found in the hoistway vent of an elevator shaft and the levels of the same spores, sampled near-simultaneously in the outdoor intake of the elevator shaft. Specific aims of this study include determining if external Penicillium/Aspergillus-like spores are entering the healthcare facility via the elevator shaft and hoistway vents. Additional aims include determining levels of Penicillium/Aspergillus-like spores outdoors, in the elevator shafts, and indoors in areas possibly affected by elevator shaft air; and, finally, to evaluate whether any effect is observed due to the installation of a hoistway vent damper, installed serendipitously during this study. ^ Methods. Between April 2010 and September 2010, a total of 3,521 air samples were collected, including 363 spore trap samples analyzed microscopically for seven spore types, and polymerase chain reaction analyses on 254 air samples. 2178 particle count measurements, 363 temperature readings and 363 relative humidity readings were also obtained from 7 different locations potentially related to the path of air travel inside and near a centrally-located and representative elevator shaft. ^ Results. Mean Penicillium/Aspergillus-like spore values were higher outside the building (530 spores/m3 of air) than inside the hoistway (22.8 spores/m3) during the six month study. Mean values inside the hospital were lower than outside throughout the study, ranging from 15 to 73 spores/m3 of air. Mean Penicillium/Aspergillus-like spore counts inside the hoistway decreased from 40.1 spores/m3 of air to 9 spores/m3 of air following the installation of a back draft damper between the outside air and the elevator shaft. Comparison of samples collected outside the building and inside the hoistway vent prior to installing the damper indicated a strong positive correlation (Spearman's Rho=0.8008, p=0.0001). The similar comparison following the damper installation indicated a moderate non-significant inverse correlation (Spearman's rho = −0.2795, p=0.1347). ^ Conclusion. Elevator shafts are one pathway for mold spores to enter a healthcare facility. A significant correlation was detected between spores and particle counts inside the hoistway and outside prior to changes in the ventilation system. The insertion of the back draft damper appeared to lower the spore counts inside the hoistway and inside the building. The mold spore counts in air outside the study building were higher in the period following the damper installation while the levels inside the hoistway and hospital decreased. Cladosporium and Penicillium/Aspergillus -like spores provided a method for evaluating indoor air quality as a natural tracer from outside the building to inside the building. Ascospores and basidiospores were not a valuable tracer due to low levels of detection during this study. ^ Installation of a back draft damper provides additional protection for the indoor environment of a hospital or healthcare facility, including in particular patients who may be immunocompromised. Current design standards and references do not require the installation of a back draft damper, but evaluation of adding language to relevant building codes should be considered. The data indicate a reduction in levels of Penicillium/Aspergillus -like spores, particle counts and a reduction in relative humidity inside of the elevator shaft after damper installation.^

¿Cómo mejorar la bioseguridad en hospitales y servicios de salud?

Bioseguridad en un sentido amplio es definida como: vida libre de peligros. Medidas de bioseguridad son acciones que contribuyen para la seguridad de la vida, en el dia a dia de las personas (ej. Cinturon de seguridad, senda peatonal). Las normas de bioseguridad engloban todas las medidas que buscan evitar riesgos fisicos (radiacion o temperatura), ergonomicos (posturales), quimicos (sustancias toxicas), biologicos (agentes infecciosos) y psicologicos (como el estres). Cada tanto, cuando hay conflictos gremiales, aparecen en las noticias hospitales que tienen ratas o cucarachas, y recien ahi se toman algunas medidas correctivas, per0 la mayoria de las instalaciones de servicios de salud no cuentan con servicios de control de plagas, o si 10s tienen no son efectivos, mas por causas administrativas que tecnicas. Es inadmisible la presencia de invertebrados y vertebrados (no humanos) en hospitales y centros de salud. Se proponen algunas medidas para mejorar la bioseguridad en esas instalaciones.

Caracterización y optimización de estructuras biofotónicas y técnicas avanzadas de interrogación para desarrollo de biosensores ópticos

El núcleo fundamental de esta tesis doctoral es un modelo teórico de la interacción de la luz con un tipo particular de biosensor óptico. Este biosensor se compone de dos regiones: en la región inferior puede haber capas de materiales con diferentes espesores y propiedades ópticas, apiladas horizontalmente; en la zona superior, sobre la que incide directamente el haz de luz, puede haber estructuras que hacen que las propiedades ópticas cambien tanto en el plano horizontal como en la dirección vertical. Estos biosensores responden ópticamente de forma diferente al ser iluminados dependiendo de que su superficie externa esté, en mayor o menor medida, recubierta con diferentes tipos de material biológico. En esta tesis se define un modelo analítico aproximado que permite simular la respuesta óptica de biosensores con estructuras en su región más externa. Una vez comprobada la validez práctica del modelo mediante comparación con medidas experimentales, éste se utiliza en el diseño de biosensores de rendimiento óptimo y en la definición de nuevas técnicas de interrogación óptica. En particular, el sistema de transducción IROP (Increased Relative Optical Power), basado en el efecto que produce la presencia de material biológico, en la potencia total reflejada por la celda biosensora en determinados intervalos espectrales, es uno de los sistemas que ha sido patentado y es objeto de desarrollo por la empresa de base tecnológica BIOD [www.biod.es/], estando ya disponibles en este momento varios dispositivos de diagnóstico basados en esta idea. Los dispositivos basados en este sistema de transducción han demostrado su eficiencia en la detección de proteínas y agentes infecciosos como los rotavirus y el virus del dengue. Finalmente, el modelo teórico desarrollado se utiliza para caracterizar las propiedades ópticas de algunos de los materiales de los que se fabrican los biosensores, así como las de las capas de material biológico formadas en las diferentes fases de un inmunoensayo. Los parámetros ópticos de las capas mencionadas se obtienen mediante el método general de ajuste por mínimos cuadrados a las curvas experimentales obtenidas en los inmunoensayos. ABSTRACT The core of this thesis is the theoretical modeling of the interaction of light with a particular type of optical biosensor. This biosensor consists of two parts: in the lower region may have layers of materials with different thicknesses and optical properties, stacked horizontally; at the top, on which directly affects the light beam, there may be structures that make optical properties change in both, the horizontal and in the vertical direction. These biosensors optically respond differently when illuminated depending on its external surface is greater or lesser extent, coated with different types of biological material. In this thesis an approximate analytical model to simulate the optical response of biosensors with structures in its outer region is defined. After verifying the practical validity of the model by comparison with experimental measurements, it is used in the design of biosensors with optimal performance and the definition of new optical interrogation techniques. In particular, the transduction system IROP (Increased Relative Optical Power) based on the effect of the presence of biological material in the total power reflected from the biosensor cell in certain spectral ranges, has been patented and is under development by the startup company BIOD [www.biod.es/], being already available at this time, several diagnostic devices based on this idea. Devices based on this transduction system have proven their efficiency in detecting proteins and infectious agents such as rotavirus and virus of dengue. Finally, the developed theoretical model is used to characterize the optical properties of some of the materials from which biosensors are fabricated, as well as the optical properties of the biological material layers formed at different stages of an immunoassay. The optical parameters of the layers above are obtained by the general method of least squares fit to the experimental curves obtained in immunoassays.

Protective long-term antibody memory by antigen-driven and T help-dependent differentiation of long-lived memory B cells to short-lived plasma cells independent of secondary lymphoid organs

Memory is a hallmark of immunity. Memory carried by antibodies is largely responsible for protection against reinfection with most known acutely lethal infectious agents and is the basis for most clinically successful vaccines. However, the nature of long-term B cell and antibody memory is still unclear. B cell memory was studied here after infection of mice with the rabies-like cytopathic vesicular stomatitis virus, the noncytopathic lymphocytic choriomeningitis virus (Armstrong and WE), and after immunization with various inert viral antigens inducing naive B cells to differentiate either to plasma cells or memory B cells in germinal centers of secondary lymphoid organs. The results show that in contrast to very low background levels against internal viral antigens, no significant neutralizing antibody memory was observed in the absence of antigen and suggest that memory B cells (i) are long-lived in the absence of antigen, nondividing, and relatively resistant to irradiation, and (ii) must be stimulated by antigen to differentiate to short-lived antibody-secreting plasma cells, a process that is also efficient in the bone marrow and always depends on radiosensitive, specific T help. Therefore, for vaccines to induce long-term protective antibody titers, they need to repeatedly provide, or continuously maintain, antigen in minimal quantities over a prolonged time period in secondary lymphoid organs or the bone marrow for sufficient numbers of long-lived memory B cells to mature to short-lived plasma cells.