Epizootic Yersinia enterocolitica in captive African green monkeys (Chlorocebus aethiops sabaeus).

Yersinia enterocolitica is a Gram-negative bacterium that typical results in enterocolitis in humans and poses significant worldwide risks to public health. An outbreak of yersiniosis in the Vervet/African green monkey colony at the WFSM during the winter of 2015-2016 accounted for widespread systemic infection with high morbidity and mortality. Most of the cases had extensive necrosis with suppuration and large colonies of bacilli in the large bowel and associated lymph nodes; however, the small intestine, stomach, and other organs were also regularly affected. Positive cultures of Yersinia enterocolitica were recovered from affected tissues in 20 of the 23 cases. Carrier animals in the colony were suspected as the source of the infection because many clinically normal animals were culture-positive during and after the outbreak. In this study, we describe the gross and histology findings and immune cell profiles in different organs of affected animals. We found increased numbers of myeloid-derived phagocytes and CD11C-positive antigen-presenting cells and fewer adaptive T and B lymphocytes, suggesting an immunocompromised state in these animals. The pathogen-mediated microenvironment may have contributed to the immunosuppression and rapid spread of the infection in the vervets. Further studies in vervets could provide a better understanding of Yersinia-mediated pathogenesis and immunosuppression, which could be fundamental to understanding chronic and systemic inflammatory diseases in humans.

Hematology and Clinical Chemistry Measures During and After Pregnancy and Age- and Sex-Specific Reference Intervals in African Green Monkeys (Chlorocebus aethiops sabaeus).

Clinical decisions and experimental analyses often involve the assessment of hematology and clinical chemistry. Using clinical pathology to assess the health status of NHP in breeding colonies or data from studies than involve pregnancy can often be complicated by pregnancy status. This study had 2 objectives regarding the hematology and clinical chemistry of African green monkeys (AGM, Chlorocebus aethiops sabaeus): 1) to compare pregnant or recently postpartum animals with nonpregnant, nonlactating animals and 2) to create age- and sex-specific reference intervals. Subjects in this study were 491 AGM from the Vervet Research Colony of the Wake Forest University Primate Center. Results indicated that changes in BUN, serum total protein, albumin, ALP, GGT, calcium, phosphorus, sodium, potassium, cholesterol, total CO2, globulins, lipase, amylase, WBC, neutrophils, lymphocytes, platelets, RBC, Hgb, and Hct occur during pregnancy and the postpartum period. Age- and sex-specific reference intervals consistent with guidelines from the American Society for Veterinary Clinical Pathology were established and further expand the understanding of how to define health in AGM on the basis of clinical pathology. The combination of understanding the changes that occur in pregnancy and postpartum and expansive reference intervals will help guide clinical and experimental decisions.

Rosiglitazone treatment improves insulin regulation and dyslipidemia in type 2 diabetic cynomolgus monkeys.

Impairment of peroxisome proliferator-activated receptor-gamma (PPAR-gamma), a nuclear receptor that regulates genes involved in lipid and glucose metabolism, may contribute to the onset of metabolic disorders such as diabetes and the accompanying dyslipidemia. Fat-derived tumor necrosis factor alpha (TNF-alpha) and the acute-phase response protein, C-reactive protein (CRP), may also have a role in the development of obesity-related insulin resistance and type 2 diabetes mellitus. In this study, a group of 14 naturally occurring, insulin-requiring, type 2 diabetic cynomolgus monkeys were used to evaluate the effects of the PPAR-gamma agonist, rosiglitazone, on glycemic and lipid parameters and serum levels of TNF-alpha and CRP. The animals were randomized into 2 groups of 7. One group was treated with 0.5 mg/kg rosiglitazone orally once a day for 7 weeks. Blood was collected for evaluation at baseline, at 2 and 7 weeks during the treatment period, and at 7 and 13 weeks after treatment. Daily insulin requirements were recorded during the entire study. Results showed daily exogenous insulin requirements were significantly reduced (P <.01) in those treated with rosiglitazone, while glycemic control was maintained. Plasma triglyceride concentrations were significantly lower (P <.01) whereas plasma cholesterol levels tended to be lower and high-density lipoprotein (HDL) concentrations tended to be higher after treatment. No significant differences were noted in TNF-alpha and CRP serum levels during the treatment period. Body weights remained steady in both groups during the study. These results suggest overall improvement in insulin regulation and lipid profiles during treatment with rosiglitazone.

Development of a nested polymerase chain reaction assay for the detection and identification of Pythium insidiosum.

Pythium insidiosum is an important cause of cutaneous and gastrointestinal disease in horses and dogs in the southeastern United States. Culture-based diagnosis of pythiosis is rarely definitive because production and identification of reproductive structures is difficult. The purpose of this study was to develop a polymerase chain reaction (PCR)-based assay for the identification of P insidiosum. Genomic DNA was extracted from 3 clinical isolates of P insidiosum and I isolate each of Pythium graminicola and Pythium arrhenomanes. The ITS I region of the ribosomal RNA gene of each isolate was amplified and sequenced, and the resultant sequences were aligned with published sequences for Pythium aphanidermatum, P acanthicum, and P myriotylum. A pair of P insidiosum-specific primers (PI-1 and PI-2) were designed from variable regions within the ITSI region. A nested PCR assay was developed in which the 1st round amplified the ITSI region by use of universal fungal primers. Second-round amplification utilized the internal P insidiosum-specific primers PI-1 and PI-2. Specificity of the assay was tested with DNA extracted from cultures of the following: 10 clinical isolates of P insidiosum and 1 isolate each of P graminicola, P irregulare, P arrhenomanes, P myriotylum, P deliense, Basidiobolus ranarum, Conidiobolus coronatus, Aspergillus terreus, Lagenidium giganteum, and a canine-pathogenic Lagenidium species. Nested PCR produced a single 105-base pair amplicon for each of the P insidiosum isolates, but did not produce amplicons for any of the other isolates. Results of this study suggest that PCR is a useful tool for the identification of P insidiosum.

Development and evaluation of an enzyme-linked immunosorbent assay for the serodiagnosis of pythiosis in dogs.

Pythiosis (caused by the aquatic oomycete Pythium insidiosum) is a devastating and often fatal cause of either severe transmural gastroenteritis or locally invasive subcutaneous disease in dogs living in the southeastern United States. Although early diagnosis is essential for successful treatment, tools available for this task are limited. Therefore, we developed and evaluated an enzyme-linked immunosorbent assay (ELISA) for the detection of anti-P insidiosum antibodies in canine serum. A soluble mycelial extract of P insidiosum was utilized as antigen in the ELISA, which was used to evaluate serum from 43 dogs with pythiosis, 8 dogs with lagenidiosis (another canine oomycosis), 16 dogs with nonoomycotic fungal or algal infections, 22 dogs with nonfungal gastrointestinal or skin disease, and 55 healthy dogs. Results were expressed as percent positivity (PP) relative to a strong positive control serum run on each plate. Medians and ranges for each of the 5 groups were as follows: pythiosis (81.7%, 50.6-98.5%), lagenidiosis (17.3%, 11.3-29.2%), other fungal or algal infections (8.2%, 4.7-15.4%), nonfungal gastrointestinal or skin disease (6.2%, 3.9-20.7%), and healthy dogs (6.7%, 3.0-15.2%). When using a cutoff value of 40% PP, the sensitivity and specificity of the ELISA both were 100%. In addition, ELISA values measured after successful surgical therapy in 2 dogs showed a decrease of anti-P insidiosum antibody concentrations into the normal range as early as 2 months after treatment. We conclude that the ELISA is a sensitive and specific test for the diagnosis of canine pythiosis, and may be a useful tool for monitoring response to medical or surgical therapy.