Laboratory Investigations of African Pouched Rats (Cricetomys gambianus) as a Potential Reservoir Host Species for Monkeypox Virus.

Monkeypox is a zoonotic disease endemic to central and western Africa, where it is a major public health concern. Although Monkeypox virus (MPXV) and monkeypox disease in humans have been well characterized, little is known about its natural history, or its maintenance in animal populations of sylvatic reservoir(s). In 2003, several species of rodents imported from Ghana were involved in a monkeypox outbreak in the United States with individuals of three African rodent genera (Cricetomys, Graphiurus, Funisciurus) shown to be infected with MPXV. Here, we examine the course of MPXV infection in Cricetomys gambianus (pouched Gambian rats) and this rodent species' competence as a host for the virus. We obtained ten Gambian rats from an introduced colony in Grassy Key, Florida and infected eight of these via scarification with a challenge dose of 4X104 plaque forming units (pfu) from either of the two primary clades of MPXV: Congo Basin (C-MPXV: n = 4) or West African (W-MPXV: n = 4); an additional 2 animals served as PBS controls. Viral shedding and the effect of infection on activity and physiological aspects of the animals were measured. MPXV challenged animals had significantly higher core body temperatures, reduced activity and increased weight loss than PBS controls. Viable virus was found in samples taken from animals in both experimental groups (C-MPXV and W-MPXV) between 3 and 27 days post infection (p.i.) (up to 1X108 pfu/ml), with viral DNA found until day 56 p.i. The results from this work show that Cricetomys gambianus (and by inference, probably the closely related species, Cricetomys emini) can be infected with MPXV and shed viable virus particles; thus suggesting that these animals may be involved in the maintenance of MPXV in wildlife mammalian populations. More research is needed to elucidate the epidemiology of MPXV and the role of Gambian rats and other species.

Telemetric left ventricular monitoring using wireless telemetry in the rabbit model.

BACKGROUND: Heart failure is a critical condition that affects many people and often results from left ventricular dysfunction. Numerous studies investigating this condition have been performed using various model systems. To do so, investigators must be able to accurately measure myocardial performance in order to determine the degree of left ventricular function. In this model development study, we employ a wireless telemetry system purchased from Data Sciences International to continuously assess left ventricular function in the rabbit model. FINDINGS: We surgically implanted pressure-sensitive catheters fitted to wireless radio-transmitters into the left ventricle of Dutch-belted rabbits. Following recovery of the animals, we continuously recorded indices of cardiac contractility and ventricular relaxation at baseline for a given time period. The telemetry system allowed us to continuously record baseline left ventricular parameters for the entire recording period. During this time, the animals were unrestrained and fully conscious. The values we recorded are similar to those obtained using other reported methods. CONCLUSIONS: The wireless telemetry system can continuously measure left ventricular pressure, cardiac contractility, and cardiac relaxation in the rabbit model. These results, which were obtained just as baseline levels, substantiate the need for further validation in this model system of left ventricular assessment.

Disaster preparedness in biocontainment animal research facilities: developing and implementing an incident response plan (IRP).

Preparing for the wide variety of disasters that can occur is challenging for any animal research facility, but the level of concern for human and animal health rises significantly when infectious agents and toxins are part of the scenario. Federal regulations provide detailed requirements for the development of an incident response plan (IRP) when select agents and toxins (SATs) are used. In addition to the usual issues associated with disaster planning, the IRP must address concerns associated with the potential theft, loss, or release of SATs that may affect both institutional personnel and the surrounding community. The level of detail in the IRP and the intensity of training should be appropriate for the level of risk involved. Regulations describe certain basic requirements but do not address the risks of SAT-exposed animals, which have been the subject of additional guidance to help implement regulatory requirements. A 2008 joint publication of the Centers for Disease Control and Prevention and the Animal and Plant Health Inspection Service describes scenarios in which SAT-exposed animals are handled in the same manner as the agent or toxin itself for the purpose of reporting a SAT theft, loss, or release. Events that resulted from the impact of Hurricane Ike at the University of Texas Medical Branch in Galveston provide a valuable opportunity to evaluate the effectiveness of the federal regulations and to build on lessons learned from this disaster. These lessons can help to supplement the regulatory requirements and improve the safety and security of handling both SATs and animals exposed to them during and after an emergency situation.

The basics of animal biosafety and biocontainment training.

The threat of biocontamination in an animal facility is best subdued by training. 'Training' is an ambiguous designation that may not be adequately appreciated in all animal facilities. The authors set down concrete training topics and provide practical advice on incorporating the basic principles of facility biosafety training--as well as the precautions and procedures that employees must know in case of accident or emergency--into various training models. They also discuss the current biosafety publications and guidelines and their relationship to biosafety training.

Successful topical respiratory tract immunization of primates against Ebola virus.

Ebola virus causes outbreaks of severe viral hemorrhagic fever with high mortality in humans. The virus is highly contagious and can be transmitted by contact and by the aerosol route. These features make Ebola virus a potential weapon for bioterrorism and biological warfare. Therefore, a vaccine that induces both systemic and local immune responses in the respiratory tract would be highly beneficial. We evaluated a common pediatric respiratory pathogen, human parainfluenza virus type 3 (HPIV3), as a vaccine vector against Ebola virus. HPIV3 recombinants expressing the Ebola virus (Zaire species) surface glycoprotein (GP) alone or in combination with the nucleocapsid protein NP or with the cytokine adjuvant granulocyte-macrophage colony-stimulating factor were administered by the respiratory route to rhesus monkeys--in which HPIV3 infection is mild and asymptomatic--and were evaluated for immunogenicity and protective efficacy against a highly lethal intraperitoneal challenge with Ebola virus. A single immunization with any construct expressing GP was moderately immunogenic against Ebola virus and protected 88% of the animals against severe hemorrhagic fever and death caused by Ebola virus. Two doses were highly immunogenic, and all of the animals survived challenge and were free of signs of disease and of detectable Ebola virus challenge virus. These data illustrate the feasibility of immunization via the respiratory tract against the hemorrhagic fever caused by Ebola virus. To our knowledge, this is the first study in which topical immunization through respiratory tract achieved prevention of a viral hemorrhagic fever infection in a primate model.

Superantigen-induced cytokine release from whole-blood cell culture as a functional measure of drug efficacy after oral dosing in nonhuman primates.

Evaluation of drug efficacy for human diseases is routinely performed in animal models for efficiency and in accordance with FDA regulations. Rhesus macaques have been used as models for various lethal diseases and correlates of immunity, as nonhuman primates (NHP) closely resemble humans. We examined the ex vivo cytokine response of superantigen-stimulated whole-blood cells as a first step to therapeutic efficacy testing for bacterial superantigen-induced shock in NHP after oral dosing of pentoxifylline. Doses of 120mg/kg of pentoxifylline effectively attenuated staphylococcal enterotoxin B-induced tumor necrosis factor alpha (TNFalpha), gamma interferon (IFNgamma) and interleukin 2 (IL-2) in ex vivo culture of NHP whole-blood cells by 88%, 81%, and 76%, respectively, whereas lower doses of 48 or 72mg/kg had no inhibitory effect. Thus cytokine release of stimulated peripheral blood cells provides a convenient biological measurement of the anti-inflammatory potency of pentoxifylline and has the advantage of assessing functional responses to a specific biotoxin of interest.

Adaptation of Plasmodium vivax to growth in owl monkeys (Aotus nancymai).

The purpose of this study was reactivation and adaptation of a strain of Plasmodium vivax to Aotus nancymai monkeys. A need arose for malarial parasites for use in serologic and molecular studies and for teaching slides. This particular strain of parasite had been characterized previously as producing high-density parasitemia in splenectomized New World monkeys and therefore represented a good candidate for reactivation. P. vivax (Vietnam II), isolated in 1970, was reactivated after adaptation in Aotus lemurinus griseimembra monkeys nearly 33 years earlier and adapted to A. nancymai monkeys. Passage was achieved by intravenous inoculation of parasite blood stages into splenectomized A. nancymai monkeys. Parasitemia was determined by analyzing daily blood smears stained with Giemsa. Maximum parasite counts ranged from 10,630 to 94,000 parasites/microl; the mean maximum parasite count for the four animals was 39,565 parasites/microl. Parasite counts of > 10,000/microl were maintained for 2 to 64 days. After only three passages of the parasite, attempts to reactive were successful. A. nancymai proved a suitable animal model for the recovery of this parasite. In conclusion, successful reactivation and adaptation of this parasite offers the capability to perform a series of diagnostic, immunologic, and molecular studies as well as to provide otherwise potentially unavailable teaching materials to healthcare professionals.

Comparative study of lung cytologic features in normal rhesus (Macaca mulatta), cynomolgus (Macaca fasicularis), and African green (Chlorocebus aethiops) nonhuman primates by use of bronchoscopy.

Invasive bronchoscopy and bronchoaveolar lavage (BAL) fluid collection represents an important tool in studies of the respiratory system of nonhuman primates. Bronchoscopy and BAL fluid collection was performed on groups of rhesus (Macaca mulatta) and cynomolgus (Macaca fasicularis) macaques and African green monkeys (Chlorocebus aethiops), and the resulting comparative lavage cytologic features are described. Analysis of the BAL fluid did not reveal significant differences among species with respect to total cells recovered or differential cellular composition. This description of the method used to lavage the nonhuman primates and the resulting lung cytologic findings provide important comparative data for three species commonly used in biomedical research.