347 Choosing an external marker for measuring intake and digestibility in ruminants

Proper nutrition is key to maintaining and improving animal productivity. Measuring intake and site and extent of digestion is essential for appropriate diet formulation. However, it is extremely difficult to accurately account for the dynamic nature of the ruminant digestive tract. External markers have long been used as a tool to measure digesta output, yet proper marker selection can be challenging. The aim of this review is to provide guidance in the selection of external markers in ruminant nutrition studies. External markers must satisfy certain requirements in order to be considered a valid marker. These requirements include, but are not limited to, being inert in the gastrointestinal tract, mixing with the digesta, and having high recovery rate in the feces. In addition, laboratory analysis needs to be easily reproducible within and amongst laboratories. Health hazards of the marker must also be kept in mind for the laboratory worker and the animal. There are a number of elements that have been utilized as external markers. Currently in the literature, chromic oxide (Cr2O3), long-chain alkanes (C32 to C36) and titanium dioxide (TiO2) are the most commonly used external markers. Each have been extensively evaluated and have their own positive and negative attributes. Results comparing fecal recoveries has been extensively reported in various diets fed to large and small ruminants. Of the three most widely utilized external markers, all have demonstrated adequate fecal recoveries, reasonable estimates of total duodenal and fecal digesta flows or output. Therefore, the selection of the appropriate marker comes down to the ease and accuracy at which analysis can be conducted, dosage rate, minimum dosage frequency, and safety to the user and animal.

COMPARATIVE STUDY BETWEEN OPTIMAL AND REDUCED FORMALIN-BASED FIXATIVE FOR NORMAL AND PATHOLOGICAL TISSUES

Objectives: This study aims to use an alternative fixative compound with reduced concentration of formalin to minimize the exposure and related side effects. Methods: Human normal and pathological tissue samples of different organs were immediately immersed in a modified fixative containing formalin, glycerin, ethanol, and hypotonic saline with pH around 7. Two time schedules were used at 8 and 12 h. Tissue samples were undergone routine processing procedure used in histopathological laboratories, scoring of samples was done, tissue sections of new compound fixative were examined for cytoplasmic, nuclear, and architectural properties and compared with 10% neutral buffered formalin (NBF). Results: Tissue samples treated with modified fixative showed good and acceptable preservation of structural, cellular details with less harmful effects when compared with those preserved with routine 10% (NBF). Conclusion: The suitability and effectiveness of reduced formalin-based fixative in histological and histopathological routine examination with minimal harmful effects for laboratory worker were clearly indicated in this study.

Occupational Exposure to the Ugandan Research Strain (MR766) of Zika Virus

A laboratory worker suffered an accidental needle-stick resulting in an exposure to the Ugandan strain (MR766) of Zika virus, which has rarely been studied in humans. We report the clinical presentation and outcomes, molecular and serological diagnostic results, and antibody response.

2802. Occupational Exposure to the Ugandan Strain of Zika Virus in a Laboratory Worker in the United States: Clinical Presentation, Viral Persistence, and Antibody Response

Background A laboratory worker suffered an accidental needle stick resulting in infection with the Ugandan strain (MR766) of Zika virus (ZIKV), a strain that has rarely been studied in humans. We report the clinical presentation and outcomes, molecular and serological diagnostic results, and immunological response. A 34-year-old Brazilian-born female laboratory researcher, presented with malaise, skin rash, myalgia and joint pain 10 days after an accidental needle stick while inoculating a mouse with ZIKV-MR766. On physical examination she had bilateral maculopapular rash on the cheeks, and tender effusions at the metacarpal and proximal interphalangeal joints and ankles. Symptoms and signs resolved within 3 weeks. ZIKV infection was confirmed by Nucleic Acid Amplification Test (Lab Corp®) in urine. Serological testing using the ZIKV IgM ELISA test from Lab Corp®, and a confirmatory plaque reduction neutralization test (PRNT) in accordance with the Centers for Disease Control and Prevention (CDC), results were negative. Methods Whole blood, plasma, urine, saliva, and a vaginal swab were collected from day (D) 14 post exposure (PE) to D104 PE. A novel, antibody competition-based ZIKV diagnostic test (highly specific for ZIKV antibodies) was performed in serum, and detection of ZIKV-MR766 genomic RNA was performed in all body fluids longitudinally. Results Antibody response revealed broad IgM response to both ZIKV-Paraiba (strain from the 2015 outbreak) and ZIKV-MR766 during the acute phase of the infection, suggesting cross-reactivity. There was no cross-reactivity against dengue or yellow fever viruses. An IgG response was detected against both ZIKV strains and increased until D104 PE. ZIKV RNA was detected in whole blood, saliva, urine, and the vaginal swab at D14 PE. At D20 PE, virus was only detectable in whole blood at a value of less than 37 copies per mL. At D23 PE, there was no detectable virus. (figure). Conclusion This case highlights the potential for ZIKV occupational exposure. Findings may be useful for the development of diagnostic tests against ZIKV as we were able to accurately determine time of exposure, presence of virus in body fluids, development of symptoms, and antibody responses after a well-documented infection. Disclosures All authors: No reported disclosures.

Understanding safety data sheets as a strategy to protect humans and the environment at the laboratory

Safety Data Sheet (SDS) gave important information for safe chemicals handling and widely used in communicating chemical hazards. Laboratory as one of the places associated with the consumption of a number of chemicals, then the worker in laboratory have to know the information chemicals used. The purpose of this research is to know the perception and understanding of workers in a laboratory toward SDS. The quantitative research was used and the collect data by questionnaire using Likert scale, then analyzed descriptively. The total sample of data was twenty-seven of laboratory worker people. The finding from this study showed that a great majority of people agree SDS has benefits for workers in the laboratory, agree the SDS should be available in the workplace, feel the need to know the contents of the SDS, but not so many people agree ‘I access SDS while working using chemicals’ and great majority of people feel ‘I obtained chemical information other than SDS’.