A Multiplex RT-PCR Method for the Detection of Reptarenavirus Infection.

Reptarenaviruses cause Boid Inclusion Body Disease (BIBD), a fatal disease of boid snakes with an economic and ecological impact, as it affects both captive and wild constrictor snakes. The clinical picture of BIBD is highly variable but often only limited. Intracytoplasmic inclusion bodies (IB), which develop in most cell types including blood cells, are the pathognomonic hallmark of BIBD; their detection represents the diagnostic gold standard of the disease. However, IBs are not consistently present in clinically healthy reptarenavirus carriers, which can, if undetected, lead to and maintain the spread of the disease within and between snake populations. Sensitive viral detection tools are required for screening and control purposes; however, the genetic diversity of reptarenaviruses hampers the reverse transcription (RT) PCR-based diagnostics. Here, we describe a multiplex RT-PCR approach for the molecular diagnosis of reptarenavirus infection in blood samples. The method allows the detection of a wide range of reptarenaviruses with the detection limit reaching 40 copies per microliter of blood. Using 245 blood samples with a reference RT-PCR result, we show that the technique performs as well as the segment-specific RT-PCRs in our earlier studies. It can identify virus carriers and serve to limit reptarenavirus spreading in captive snake collections.

Reptarenavirus S Segment RNA Levels Correlate with the Presence of Inclusion Bodies and the Number of L Segments in Snakes with Reptarenavirus Infection-Lessons Learned from a Large Breeding Colony.

Reptarenaviruses cause boid inclusion body disease (BIBD), a fatal disease particularly impacting captive boa constrictor collections. The development of cytoplasmic inclusion bodies (IBs) comprising reptarenavirus nucleoprotein (NP) in many cell types of affected snakes is characteristic of BIBD. However, snakes can harbor reptarenaviruses without showing IBs, hence representing carriers and a potential source of transmission. The RNA genome of reptarenaviruses comprises a small (S) and a large (L) segment, and the snakes with BIBD commonly carry a swarm of reptarenavirus segments. To design sensitive and reliable tools for the diagnosis of reptarenavirus infection in snake colonies, we used metatranscriptomics to determine the reptarenavirus segments present in a large boa constrictor breeding colony. The analysis identified one reptarenavirus S segment and three L segments in the colony. The sequence data served to design real-time reverse transcription-PCR (RT-PCR) targeting the found S segment. This allowed us to identify all infected animals and to quantify the S segment RNA levels, which we found to correlate with the presence of IBs. We further found a positive correlation between the number of L segments and the S segment RNA level, which could suggest that L segment excess also contributes to the IB formation. Information on cohousing of the snakes showed a clear association of reptarenavirus infection with cohousing in general and cohousing with infected animals. Information on breeding and offspring confirmed that vertical transmission occurred. Furthermore, our data suggest that some animals might be able to clear the infection or at least exhibit transient or intermittent viremia. IMPORTANCE Boid inclusion body disease (BIBD) is caused by reptarenavirus infection, and while reptarenavirus nucleoprotein is the main component of the inclusion bodies (IBs) characteristic of BIBD, not all reptarenavirus-infected snakes demonstrate IBs in their cells. Identification of infected individuals is critical for controlling the spread of the disease; however, the genetic divergence of reptarenaviruses complicates reverse transcription-PCR (RT-PCR)-based diagnostics. Here, we tested a next-generation-sequencing-based approach to establish a tailored "colony-specific" set of diagnostic tools for the detection of reptarenavirus small (S) and large (L) genome segments. With this approach, we could demonstrate that an S-segment-specific RT-PCR is highly effective in identifying the infected individuals. We further found the S segment RNA level to positively correlate with the presence of IBs and the number of L segments, which could direct future studies to identify the BIBD pathogenetic mechanisms.

A Muskrat (Ondatra zibethicus) with alveolar echinococcosis bitten to death by a dog - a challenge for the forensic pathologist as an expert witness.

We present a case that illustrates the complex contexts in which forensic veterinary pathology examinations may be carried out. A wild muskrat (Ondatra zibethicus) had died after a putative bite attack from a domestic dog. Bite attacks by privately owned dogs on wild animals in Switzerland violate the Swiss civil (and/or hunting) laws, and dog owners are generally punished with a monetary fine; hence, this case appeared to be straightforward. However, the results of the subsequent post-mortem examination of the muskrat not only confirmed the presence of injuries related to the bite attack, but also detected alveolar echinococcosis (ie, infestation with Echinococcus multilocularis). Therefore, as an intermediate host of the parasite, the muskrat could have contributed to further spread of a severe helminthic zoonosis had it not been killed by the dog. It was probably an easy prey for the dog as it probably had been weakened by the disease. Furthermore, muskrats are considered as pests and invasive species, and are non-indigenous huntable game in Switzerland and other European countries in which programmes for the prevention of their further spread and endangerment of native wildlife are established. The role of the forensic veterinary pathologist in such a complex scenario is to adopt an unbiased approach and establish the facts, which in this case was to determine the cause of death and suspected perpetrator, identify any concomitant and/or underlying diseases and consider potential animal welfare issues.

[Surgery site healing disorder following laparotomy in cattle: a retrospective study]. / Wundheilungsstörungen nach abdominal-chirurgischen Eingriffen beim Rind: eine retrospektive Studie.

OBJECTIVES: Wound healing processes in consequence to bovine abdominal surgery performed from 2007 to 2016 at the University of Veterinary Medicine in Vienna were retrospectively assessed. The aim of this study was to evaluate the occurrence of wound healing complications following abdominal surgery in cattle during this 10-year-period as well as to identify possible risk factors such as elevated temperatures. MATERIAL AND METHODS: Surgical procedures finding inclusion comprised ileus, left and right abomasal displacement, caecal dilation or displacement (right flank laparotomies), foreign body syndrome (left flank laparotomy), and umbilical surgery. Additionally, weather data during the study period were collected in order to investigate the possible association between ambient temperatures and wound healing disorders. RESULTS: During this period 1365 abdominal surgical procedures were performed. The majority (68.6 %) of the cattle were Simmental cows, followed by 19.6 % Holstein Friesians. Female animals were overrepresented (73.0 %), and 24.0 % of the patients were calves. In 156 cases (11.7 %), a postoperative wound healing disorder (WHD) occurred. The majority of the laparotomies were performed from the right side; of these 21.4 % were left abomasal displacements and 21.7 % ileus surgeries. Left abomasal displacements (24.4 %) and surgery in the umbilical region (21.2 %) were associated with a higher occurrence of WHDs than other abdominal surgical procedures. Animals with right abomasal displacement developing WHDs were significantly younger than those without a WHD. A significant association between WHD frequency and higher temperatures could not be demonstrated. A total of 34.6 % WHD occurred during the summer months (June-September). However, the probability of developing WHDs increased significantly starting at an environmental temperature of 12.5 °C. Most WHD were observed in May (17.1 %) followed by July (15.6 %) and June (15.3 %). CONCLUSION AND CLINICAL RELEVANCE: The occurrence of WHDs is influenced by numerous different factors such as age of the animal, disease, and type of the surgical procedure. The environmental temperature may increase the risk to develop a WHD but is only one parameter of a multifactorial process.

Non-Infectious, Necrotizing and Granulomatous Aortitis in a Female Gorilla.

A 41-year-old female captive gorilla with progressive weight loss and hydrothorax of unknown origin was euthanized and submitted for necropsy. The ascending aorta showed intimal aortic thickenings, consistent with so called 'tree bark' changes. Microscopic examination revealed a non-infectious, necrotizing and granulomatous aortitis with no evidence of systemic vasculitis or infectious disease elsewhere in the body. While rare, large vessel vasculitides should be considered as a differential diagnosis in gorillas presenting with progressive non-specific signs and vascular intimal changes.