Comparative medicine最新文献

As the use of zebrafish (Danio rerio) as a research model continues to rise, so too will the shipping and sharing of zebrafish strains across collaborating institutions. If done incorrectly, shipping can result in significant mortality, welfare concerns, and loss of valuable resources for researchers and research institutions. Here we introduce a novel method to track temperatures of zebrafish containers during shipping and show that internal packaging temperatures are directly affected by the external temperatures. We used temperature logging Thermochron iButtons to track the temperatures of 2 packages containing adult zebrafish that were shipped overnight from Dallas, TX to Columbus, OH during winter following recommended fish shipping guidelines. We found that the external packaging of both boxes of fish were exposed to temperatures that had previously been shown to be lethal to zebrafish. However, internal temperatures and, more specifically, water temperature, stayed within 24.0 to 26.5^°C during shipment, resulting in 100% survival of adult zebrafish. This novel method of tracking packaging temperatures of live fish during shipping can help to inform fish health status on arrival.

FELASA and AALAS established a joint working group to advise on good practices for the exchange of fish for research. In a first manuscript, the working group made recommendations for health monitoring and reporting of monitoring results. The focus of this second related manuscript is biosecurity in fish facilities. First, we define the risk of contamination of personnel by zoonotic pathogens from fish or from system water, including human mycobacteriosis. Preventive measures are recommended, such as wearing task-specific personal protective equipment. Then we discuss biosecurity, highlighting the establishment of biosecurity barriers to preserve the health status of a facility. A functional biosecurity program relies on integration of the entire animal facility organization, including the flow of staff and animals, water treatments, and equipment sanitation. Finally, we propose 4 steps for introducing new fish colonies: consideration of international trade and national restrictions; assessing risk according to fish source and developmental stage; establishing quarantine barriers; and the triage, screening, and treatment of newly imported fish. We then provide 3 realistic sample scenarios to illustrate practical biosecurity risk assessments and mitigation measures based on considerations of health status and quarantine conditions.

The exchange of fish for research may expose an aquatic laboratory to pathogen contamination as incoming fish can introduce bacteria, fungi, parasites, and viruses capable of affecting both experimental results and fish and personnel health and welfare. To develop risk mitigation strategies, FELASA and AALAS established a joint working group to recommend good practices for health monitoring of laboratory fish. The recommendations address all fish species used for research, with a particular focus on zebrafish (Danio rerio). First, the background of the working group and key definitions are provided. Next, fish diseases of high impact are described. Third, recommendations are made for health monitoring of laboratory fishes. The recommendations emphasize the importance of daily observation of the fish and strategies to determine fish colony health status. Finally, report templates are proposed for historical screening data and aquatic facility description to facilitate biohazard risk assessment when exchanging fish.

Alfaxalone, a synthetic neuroactive steroid, has been tested as an immersion anesthetic in ornamental fish, but its safety and efficacy in sport fish have not been investigated. In the current study, we compared the physiologic and behavioral effects of alfaxalone with those of tricaine methanesulfonate (MS222) for anesthesia of rainbow trout (Oncorhynchus mykiss) via water immersion. We also analyzed alfaxalone-exposed tissues to determine residue clearance times. Fish were anesthetized for 10 min by immersion in low-dose alfaxalone (A_low; 5 mg/L induction, 1 mg/L maintenance), high-dose alfaxalone (A_high; 5 mg/L induction, 2 mg/L maintenance), or MS222 (MS; 150 mg/L induction, 100 mg/L maintenance). Fish received all 3 treatments, separated by a washout period of at least 18 d in a blinded, complete crossover design. We hypothesized that immersion in A_low or A_high would provide a stable plane of anesthesia in rainbow trout, with dose-dependent time to recovery, and that opercular rates and depths of anesthesia would be equivalent to that of MS222. The time to anesthesia induction was longer for alfaxalone than MS222 but averaged less than 100 s. The time to recovery from anesthesia was also longer for alfaxalone than MS222, with significantly shorter recovery time for A_{low than for Ahigh}. All treatments decreased opercular rate and response to noxious stimuli. Alfaxalone residue clearance was greater than 80% from all tissues within 1 h, greater than 99% from muscle within 4 h, and 100% from all tissues within 36 h after exposure. We conclude that alfaxalone immersion at 5 mg/L for induction and 2 mg/L for maintenance provides a safe, viable alternative to MS222 for the anesthesia of rainbow trout.

Otitis externa (OE) is a condition that involves inflammation of the external ear canal. OE is a commonly reported condition in humans and some veterinary species (for example, dogs, cats), but has not been reported in the literature in macaques. Here, we present a case series of acute and chronic OE likely precipitated by abrasion of the ear canal with a tympanic membrane electrode in 7 adult male rhesus macaques (Macaca mulatta). All animals displayed purulent, mucinous discharge from 1 or both ears with 3 macaques also displaying signs of an upper respiratory tract (URT) infection during the same period. A variety of diagnostic and treatment options were pursued including consultation with an otolaryngologist necessitated by the differences in response to treatment in macaques as compared with other common veterinary species. Due to the nature of the studies in which these macaques were enrolled, standard audiological testing was performed before and after OE, including tympanometry, auditory brainstem responses (ABRs), and distortion product otoacoustic emissions (DPOAEs). After completion of study procedures, relevant tissues were collected for necropsy and histopathology. Impaired hearing was found in all macaques even after apparent resolution of OE signs. Necropsy findings included abnormalities in the tympanic membrane, ossicular chain, and middle ear cavity, suggesting that the hearing impairment was at least partly conductive in nature. We concluded that OE likely resulted from mechanical disruption of the epithelial lining of the ear canal by the ABR electrode, thereby allowing the development of opportunistic infections. OE, while uncommon in macaques, can affect them and should be included as a differential diagnosis of any macaque presenting with otic discharge and/or auricular discomfort.

Campylobacter jejuni is an important cause of bacterial gastroenteritis worldwide and is linked to Guillain-Barré syndrome (GBS), a debilitating postinfectious polyneuropathy. The immunopathogenesis of GBS involves the generation of antibodies that are cross reactive to C. jejuni lipooligosaccharide and structurally similar peripheral nerve gangliosides. Both the C. jejuni infecting strain and host factors contribute to GBS development. GBS pathogenesis is associated with Th2-mediated responses in patients. Moreover, induction of IgG1 antiganglioside antibodies in association with colonic Th2-mediated immune responses has been reported in C. jejuni-infected C57BL/6 IL10^-/- mice at 4 to 6 wk after infection. We hypothesized that, due to their Th2 immunologic bias, BALB/c mice would develop autoantibodies and signs of peripheral neuropathy after infection with a GBS patient-derived strain of C. jejuni (strain 260.94). WT and IL10^-/- BALB/c mice were orally inoculated with C. jejuni 260.94, phenotyped weekly for neurologic deficits, and euthanized after 5 wk. Immune responses were assessed as C. jejuni-specific and antiganglioside antibodies in plasma and cytokine production and histologic lesions in the proximal colon. Peripheral nerve lesions were assessed in dorsal root ganglia and their afferent nerve fibers by scoring immunohistochemically labeled macrophages through morphometry. C. jejuni 260.94 stably colonized both WT and IL10^-/- mice and induced systemic Th1/Th17-mediated immune responses with significant increases in C. jejuni-specific IgG2a, IgG2b, and IgG3 plasma antibodies. However, C. jejuni 260.94 did not induce IgG1 antiganglioside antibodies, colitis, or neurologic deficits or peripheral nerve lesions in WT or IL10^-/- mice. Both WT and IL10^-/- BALB/c mice showed relative protection from development of Th2-mediated immunity and antiganglioside antibodies as compared with C57BL/6 IL10^-/- mice. Therefore, BALB/c mice infected with C. jejuni 260.94 are not an effective disease model but provide the opportunity to study the role of immune mechanisms and host genetic background in the susceptibility to post infectious GBS.