Virological and Immunological Outcomes in Rhesus Monkeys after Exposure to Dengue Virus-Infected Aedes aegypti Mosquitoes

This study describes the natural history of dengue virus (DENV) infection in rhesus monkeys exposed to the bites of DENV-infected Aedes aegypti mosquitoes. Dengue virus–infected mosquitoes were generated by either intrathoracic inoculation or by oral feeding on viremic blood meals. Each of the six rhesus monkeys that were fed upon by intrathoracically infected mosquitoes developed non-structural protein 1 (NS1) antigenemia and an IgM response; viremia was detected in 4/6 individuals. No virological or immunological evidence of DENV infection was detected in the three monkeys exposed to mosquitoes that had been orally infected with DENV. These results demonstrate the utility of mosquito-borne challenge of rhesus monkeys with DENV.

Retrospective analyses of serum lipids and lipoproteins and severity of disease in 60Co-irradiated Sus scrofa domestica and Macaca mulatta

Profound neutropenia that provides an opportunity for infections to develop into sepsis remains an important cause of morbidity and mortality in patients after irradiation. Human clinical studies find extremely low concentrations of cholesterol (less than 120 mg/dl) associated with high risk of death in critically ill adult patients admitted to intensive care units. This retrospective study was initiated as part of separate investigations of radiation-induced acquired infections in 2 large animal species receiving high-dose whole-body irradiation from a 60Co gamma-photon source. Nine Yucatan minipigs (Sus scrofa domestica) and 16 rhesus macaques (Macaca mulatta) were evaluated for sepsis, serum lipid and lipoprotein concentrations, and other blood parameters. For each species, animals were grouped into 2 categories--septic and nonseptic--and severity of disease was quantified by use of a scoring system. Significantly lower high-density lipoprotein (HDL) concentrations were found in the septic pigs at 24 and 48 h as compared with nonseptic pigs. HDL was significantly decreased in septic macaques within 24 h and 3 to 4, 6 to 7, and 9 to 10 d after diagnosis of sepsis, compared with that in nonseptic macaques. Coupled with hypocholesterolemia, decreased serum HDL was the parameter that was associated with disease severity at the time of sampling. Our data indicate that HDL is a reliable marker for severity of disease in these 2 preclinical models of irradiation-induced sepsis.

Noninfectious complications due to vascular access ports (VAPs) in Yucatan minipigs (Sus scrofa domestica)

Vascular access ports (VAPs) for studies requiring intermittent or continuous infusion and frequent sampling are well accepted and widely used in large animal species. However, the use of medical devices such as VAPs to facilitate sample collection can lead to complications. Noninfectious complications of VAP implantation can result from thrombotic or mechanical obstructions, other mechanical problems, and animal-associated complications. To facilitate our research, we surgically implanted VAPs in the right external jugular vein of 6 adult male and 3 female Yucatan miniswine (age, 12 mo) to enable collection of blood samples every 30 min for 8 h and then every 8 h for as long as 60 d. The VAPs were operational an average of 35.6 d (range, 29 to 56 d) and had an overall success rate of 77.8% with 7 of 9 VAPs functional. In these 7 animals, 53.1 samples on average (range, 28 to 95 samples) were collected from each VAP. Rates of noninfectious complications were 60% for thrombotic events and 40% for nonthrombotic events over the course of this study.