Select Toxicologic Pathology Case Studies of the Hepatobiliary System.

This case study session of the hepatobiliary system was held during the 42nd Annual Society of Toxicologic Pathology Symposium in Summerlin, Nevada. The case studies highlighed potential hepatic and biliary toxicity liabilities. This article comprises several of the case studies that were presented during the session which included copper-associated hepatitis in a dog, sinusoidal obstruction syndrome in non-human primates, hepatic cytoplasmic alteration in mice and rats, and Kupffer cell hyperplasia/granulomatous inflammation in rats. Presenters, when applicable, provided case signalment, anatomic/clinical pathology data, and diagnoses and discussed potential pathogeneses.

Safety in Chemical and Biomedical Laboratories: Guidelines for the Use of Head Covers by Female Muslim Scientists.

Introduction: Personal protective equipment (PPE) complements the safety measures required for working in various laboratories. The main purpose of PPE is to limit the exposure of laboratory personnel and the environment to hazardous chemicals and biological materials. Despite the wide acceptance of PPE, limited accommodation exists for customization of these items based on personal or cultural preferences. Discussion: This article describes the basic recommendations and specifications for Muslim women's head covers as a part of PPE requirements in chemical and biological laboratories. Conclusions: These guidelines will significantly help safety professionals, laboratorians, and teachers to plan accordingly and customize PPE that will not only be safe but also fit the needs of scientists of varying cultural backgrounds.

Pathology in Practice.

In collaboration with the American College of Veterinary Pathologists.

In Vitro Infection Dynamics of Japanese Encephalitis Virus in Established Porcine Cell Lines.

Japanese encephalitis virus (JEV) is a zoonotic mosquito-borne pathogen that regularly causes severe neurological disease in humans in Southeast Asia and the Western Pacific region. Pigs are one of the main amplifying hosts of JEV and play a central role in the virus transmission cycle. The objective of this study was to identify in vitro cell systems to investigate early effects of JEV infection including viral replication and host cell death. Here, we demonstrate the susceptibility of several porcine cell lines to the attenuated genotype III JEV strain SA14-14-2. Monolayers of porcine nasal turbinate (PT-K75), kidney (SK-RST), testis (ST), and monocyte-derived macrophage (CΔ2+) cells were infected with SA14-14-2 for up to five days at a multiplicity of infection (MOI) of 0.1. The hamster kidney cell line BHK-21, previously shown to be susceptible to SA14-14-2, was used as a positive control. Culture supernatants and cells were collected between 0 and 120 h post infection (hpi), and monolayers were observed for cytopathic effect (CPE) using brightfield microscopy. The number of infectious virus particles was quantified by plaque assay and cell viability was determined using trypan blue staining. An indirect immunofluorescence assay was used to detect the presence of JEV NS1 antigens in cells infected at 1 MOI. All four porcine cell lines demonstrated susceptibility to SA14-14-2 and produced infectious virus by 12 hpi. Virus titers peaked at 48 hpi in CΔ2+, BHK-21, and SK-RST cells, at 72 hpi in PT-K75, and at 120 hpi in ST cells. CPE was visible in infected CΔ2+ and BHK-21 cells, but not the other three cell lines. The proportion of viable cells, as measured by trypan blue exclusion, declined after 24 hpi in BHK-21 and 48 hpi in CΔ2+ cells, but did not substantially decline in SK-RST, PT-K75 or ST cells. At 48 hpi, JEV NS1 was detected in all infected cell lines by fluorescence microscopy. These findings demonstrate several porcine cell lines which have the potential to serve as useful research tools for investigating JEV infection dynamics and host cell mechanisms in a natural amplifying host species, such as pigs, in vitro.

Brucella abortus and Pregnancy in Mice: Impact of Chronic Infection on Fertility and the Role of Regulatory T Cells in Tissue Colonization.

Stealthy intracellular bacterial pathogens are known to establish persistent and sometimes lifelong infections. Some of these pathogens also have a tropism for the reproductive system, thereby increasing the risk of reproductive disease and infertility. To date, the pathogenic mechanism involved remains poorly understood. Here, we demonstrate that Brucella abortus, a notorious reproductive pathogen, has the ability to infect the nonpregnant uterus, sustain infection, and induce inflammatory changes during both acute and chronic stages of infection. In addition, we demonstrated that chronically infected mice had a significantly reduced number of pregnancies compared to naive controls. To investigate the immunologic mechanism responsible for uterine tropism, we explored the role of regulatory T cells (Tregs) in the pathogenesis of Brucella abortus infection. We show that highly suppressive CD4+FOXP3+TNFR2+ Tregs contribute to the persistence of Brucella abortus infection and that inactivation of Tregs with tumor necrosis factor receptor II (TNFR2) antagonistic antibody protected mice by significantly reducing bacterial burden both systemically and within reproductive tissues. These findings support a critical role of Tregs in the pathogenesis of persistence induced by intracellular bacterial pathogens, including B. abortus Results from this study indicate that adverse reproductive outcomes can occur as sequelae of chronic infection in nonpregnant animals and that fine-tuning Treg activity may provide novel immunotherapeutic and prevention strategies against intracellular bacterial infections such as brucellosis.

Building the Evidence Base for the Prevention of Raw Milk-Acquired Brucellosis: A Systematic Review.

Background: The scientific evidence of the health risks associated with the consumption of raw milk has been known for a long time. However, less clear is the impact of acquiring infectious diseases from raw milk consumption in the United States (US) due to incomplete reporting of cases and the complex factors associated with the sale and consumption of raw milk. Investigations of this current study focused on human brucellosis, one of the infectious diseases commonly acquired through the consumption of raw milk and milk products, and which continues to be a public health threat worldwide. Methodology: A qualitative systematic review of the sources of opinions that contribute to the increased trend of raw milk sales and consumption in the US was conducted. Results: Interestingly, opinions about the sale of raw milk and/or the benefits arising from its consumption varied by US region, with the proportion of messages supporting raw milk consumption being highest in the Northeast compared to other US regions. Several evidence gaps and factors that possibly contribute to the increased prevalence of raw milk-acquired brucellosis were identified including inadequate monitoring of the raw milk sales process and lack of approved diagnostic methods for validating the safety of raw milk for human consumption. Conclusions: The unavailability of data specifying brucellosis cases acquired from raw milk consumption have precluded the direct association between raw milk and increased brucellosis prevalence in the United States. Nevertheless, the evidence gaps identified in this study demonstrate the need for intensified surveillance of raw-milk acquired infectious diseases including human brucellosis; establishment of safety and quality control measures for the process of selling raw milk; and design of an effective strategy for the prevention of raw milk-acquired infectious diseases including brucellosis. Overall, for the first time, this study has not only shown the gaps in evidence that require future investigations, but also, variations in the perception of raw milk consumption that may impact disease acquisition in different US regions.

A systematic review and meta-analysis of the prevalence of osteoarticular brucellosis.

BACKGROUND: Infection of bones and joints remains one of the most commonly described complications of brucellosis in humans and is predominantly reported in all ages and sexes in high-risk regions, such as the Middle East, Asia, South and Central America, and Africa. We aimed to systematically review the literature and perform a meta-analysis to estimate the global prevalence of osteoarticular brucellosis (OAB). METHODOLOGY: Major bibliographic databases were searched using keywords and suitable combinations. All studies reporting the incidence and clinical manifestations of osteoarticular brucellosis in humans, and demonstrated by two or more diagnostic methods (bacteriological, molecular, serological, and/or radiographic) were included. Random model was used, and statistical significance was set at 0.05. PRINCIPAL FINDINGS: A total of 56 studies met the inclusion criteria and were included in the systematic review and meta-analysis. There was an evidence of geographical variation in the prevalence of osteoarticular disease with estimates ranging from 27% in low-risk regions to 36% in high-risk regions. However, the difference was not significant. Thus, brucellosis patients have at least a 27% chance of developing osteoarticular disease. CONCLUSIONS: The prevalence of OAB is not dependent on the endemicity of brucellosis in a particular region. Hence, further research should investigate the potential mechanisms of OAB, as well as the influence of age, gender, and other socioeconomic factor variations in its global prevalence, as this may provide insight into associated exposure risks and management of the disease.

MELANOMA IN GOLDEN AND KING WILDEBEESTS ( CONNOCHAETES TAURINUS).

Pigmentation of the skin is a crucial component in the pathogenesis of melanocytic neoplasms and other skin-related tumors, as melanin is known to function in both the absorbance of ultraviolet radiation and as an antioxidant. Very limited information exists regarding the incidence and metastatic potential of neoplastic conditions of the skin in game animals, especially wildebeests, relative to domestic animals. Four cases of cutaneous melanoma in color-variant golden and king wildebeests ( Connochaetes taurinus) (from 2014 to 2015) in South Africa were investigated. Melanoma in these captive animals was characterized using histopathology, transmission electron microscopy, and an immunohistochemistry panel, which consisted of monoclonal antibodies against three melanocytic markers: Melan A, PNL2, and S100. Overall, 2/4 cases (50%) of the melanocytic neoplasms stained strongly positive for all the melanocytic markers, while 4/4 cases (100%) stained positively for at least one of the markers. Cutaneous melanocytic neoplasia has not been reported in wildebeests; the current study suggests that selection of wildebeests for coat color potentially predisposes to this condition.

Staphylococcus aureus in two municipal abattoirs in Nigeria: Risk perception, spread and public health implications.

Staphylococcus aureus is a zoonotic pathogen of significant public health concern. Information on the prevalence and risk factors facilitating bacterial colonization and spread under abattoir settings in Nigeria are scarce. This cross-sectional study was designed to determine prevalence of S. aureus as well as risk factors on knowledge and practices facilitating pathogen carriage among workers and slaughter animals in two municipal abattoirs of Ilorin and Ibadan, Nigeria. Swab samples (n = 1671) from nostrils of cattle, goats, pigs and abattoir workers, and from meat tables and abattoir walls were collected for detection of S. aureus. A questionnaire was administered to 275 workers to elucidate risk factors of pathogen carriage applying a logistic regression model. S. aureus prevalence was 6.5%. In total, MSSA and MRSA were detected at a frequency of 5.4% and 1.1%. Molecular analysis of the isolates revealed 19 different spa types, including a novel spa type (t16751). Gender, marital status, occupation and abattoir location were factors influencing worker's practices in relation to pathogen carriage and spread in the abattoir setting. This present study detected not only low MSSA and MRSA prevalence, in both abattoirs but also low risk perception and hygiene practices employed by abattoir workers. Good practices among workers at Nigerian abattoirs are needed to mitigate S. aureus carriage. Further studies expounding the antibiotic resistance and relationships of MSSA and MRSA strains detected in this study are needed to complement understanding of the spread of S. aureus in the abattoir food chain.

Serological detection of Tick-Borne Relapsing Fever in Texan domestic dogs.

Tick-Borne Relapsing Fever (TBRF) is caused by spirochetes in the genus Borrelia. Very limited information exists on the incidence of this disease in humans and domestic dogs in the United States. The main objective of this study is to evaluate exposure of dogs to Borrelia turicatae, a causative agent of TBRF, in Texas. To this end, 878 canine serum samples were submitted to Texas A&M Veterinary Medical Diagnostic Laboratory from October 2011 to September 2012 for suspected tick-borne illnesses. The recombinant Borrelial antigen glycerophosphodiester phosphodiesterase (GlpQ) was expressed, purified, and used as a diagnostic antigen in both ELISA assays and Immunoblot analysis. Unfortunately, due to significant background reaction, the use of GlpQ as a diagnostic marker in the ELISA assay was not effective in discriminating dogs exposed to B. turicatae. Nevertheless, immunoblot assays showed that 17 out of 853 samples tested were considered to be seropositive, which constitutes 1.99% of all Texas samples tested in this study. The majority of positive samples were from central and southern Texas. Exposure to TBRF spirochetes may be seasonal, with 70.59% (12 out of 17) of the cases detected between June and December. In addition, 2 out of the 17 sero-reactive cases (11.76%) showed reactivity to both B. burgdorferi (causative agent of Lyme disease) and B. turicatae (a causative agent of TBRF). This is the first report of TBRF sero-prevalence in companion animals in an endemic area. Our findings further indicate that B. turicatae is maintained in domestic canids in Texas in regions where human disease also occurs, suggesting that domestic dogs could serve as sentinels for this disease.

Seroprevalence of Borrelia burgdorferi antibodies in white-tailed deer from Texas.

Lyme Disease is caused by the bacterial pathogen Borrelia burgdorferi, and is transmitted by the tick-vector Ixodes scapularis. It is the most prevalent arthropod-borne disease in the United States. To determine the seroprevalence of B. burgdorferi antibodies in white-tailed deer (Odocoileus virginianus) from Texas, we analyzed serum samples (n = 1493) collected during the 2001-2015 hunting seasons, using indirect ELISA. Samples with higher sero-reactivity (0.803 and above) than the negative control group (0.662) were further tested using a more specific standardized western immunoblot assay to rule out false positives. Using ELISA, 4.7% of the samples were sero-reactive against B. burgdorferi, and these originated in two eco-regions in Texas (Edwards Plateau and South Texas Plains). However, only 0.5% of the total samples were sero-reactive by standardized western immunoblot assay. Additionally, both ELISA and standardized western immunoblot assay results correlated with an increased incidence in human Lyme Disease cases reported in Texas. This is the first longitudinal study to demonstrate fluctuation in sero-reactivity of white-tailed deer to B. burgdorferi sensu stricto antigens in southern United States. Future ecological and geographical studies are needed to assess the environmental factors governing the prevalence of Lyme Disease in non-endemic areas of the southern United States.