Bluetongue and epizootic haemorrhagic disease in wildlife with emphasis on the South American scenario

Bluetongue and epizootic hemorrhagic disease affect domestic ruminants and cervids. However, other species may act as pathogen carriers in the transition of bluetongue virus (BTV) and epizootic hemorrhagic disease virus (EHDV). The wild species affected by these diseases manifest a variable range of clinical signs and lesions, and while some species appear to be extremely susceptible, showing high levels of mortality, some are resistant to these pathogens, acting as potential reservoirs of these orbiviruses.  The purpose of the following review is to describe the clinical and pathological manifestations related to these diseases in wild species and to review studies performed on non-domestic species in South America, emphasizing the challenges of studying infectious diseases in free-living animals and the gaps in knowledge about bluetongue and epizootic haemorrhagic disease epidemiology. These gaps should be filled by more studies on the range of species affected and the transmission mechanisms, including in domestic species.

Multiple bluetongue virus serotypes causing death in Brazilian dwarf brocket deer (Mazama nana) in Brazil, 2015-2016.

Bela Vista Biological Sanctuary (RBV) is a protected area of Itaipu Binacional, a hydroelectric power company located on the border of Brazil and Paraguay. A captive population of Brazilian dwarf brocket deer (Mazama nana, Cervidae, Artiodactyla) is maintained for conservation purposes. Despite the reproductive success of the animals, outbreaks of a fatal hemorrhagic disease have been registered over the years, compromising conservation efforts. In order to identify the etiological agents of these hemorrhagic diseases, 32 captive Brazilian dwarf brockets were sampled to investigate bluetongue virus (BTV), epizootic hemorrhagic disease (EHD), and adenovirus hemorrhagic disease (AHD), in 2015. Only one deer (1/32; 3.12%) was seropositive for BTV. After this survey, five animals died in the early autumn of 2015 and 2016, again presenting clinical signs of hemorrhagic disease. Using RT-qPCR, RT-PCR and DNA sequencing, five BTV serotypes (3, 14, 18, 19, and 22) were identified in blood and tissues collected during necropsies. These BTV serotypes had not been previously described or isolated in Brazil, either in wild or domestic ruminants. Additionally, differential diagnosis was performed for EHD and AHD, but all samples were negative for both diseases. The multiple distinct BTV serotypes identified in these outbreaks resulted in a high lethality (100%) of Brazilian dwarf brockets and indicated that various BTV serotypes are circulating in the area.

Effect of low-level laser therapy on incorporation of block allografts.

OBJECTIVE: To assess the effect of low-level laser therapy (LLLT) on the incorporation of deep-frozen block allografts in a rabbit model. BACKGROUND DATA: Studies have shown that LLLT has beneficial effects on tissue repair and new bone formation. METHODS: Bone tissue was harvested from two rabbits, processed by deep-freezing and grafted into the calvaria of 12 animals, which were then randomly allocated into two groups: experimental (L) and control (C). Rabbits in group L were irradiated with an aluminum gallium arsenide diode laser (AlGaAs; wavelength 830 nm, 4 J/cm(2)), applied to four sites on the calvaria, for a total dose of 16 J/cm(2) per session. The total treatment dose after eight sessions was 128 J/cm(2). Animals were euthanized at 35 (n = 6) or 70 days (n = 6) postoperatively. RESULTS: Deep-freeze-processed block allografts followed by LLLT showed incorporation at the graft-host interface, moderate bone remodeling, partial filling of osteocyte lacunae, less inflammatory infiltrate in the early postoperative period, and higher collagen deposition than the control group. CONCLUSION: Optical microscopy and scanning electron microscopy showed that allograft bone processed by deep-freezing plus LLLT is suitable as an alternative for the treatment of bone defects. Use of the deep-freezing method for processing of bone grafts preserves the structural and osteoconductive characteristics of bone tissue.

Effects of intraarticular ropivacaine and morphine on lipopolysaccharide-induced synovitis in horses.

OBJECTIVE: To compare the intraarticular (IA) analgesic effects of ropivacaine and morphine in horses with experimentally induced synovitis. STUDY DESIGN: Randomized, blinded cross-over design. ANIMALS: Twelve healthy mixed breed horses between 8-15 years old. METHODS: Synovitis was induced in the left radio-carpal joint with an injection of lipopolysaccharide (Escherichia coli 055:B5). Six hours later, the horses were treated with an IA injection of 40 mg of ropivacaine (ROPI), 40 mg of morphine (MOR), 20 mg of ropivacaine added to 20 mg of morphine in saline (RM) or 4 mL of saline (SAL), as control. Analgesia was measured subjectively using a numerical rating scale, a simple descriptive scale, pain upon maximal flexion of the carpus and by the range of motion exhibited by the affected joint. Data are reported as mean +/- SD and were analyzed using anova. Blood and synovial data were analyzed by split plots in time with units (treatments: SAL, ROPI, MOR and RM) and subunits (times: T0-24), in a completely randomized design with six replicates. Mean comparisons were made by Tukey's test; differences were considered significant at p < 0.05. RESULTS: Ropivacaine had a clinical analgesic effect with a relative short duration ( approximately 2.5 to 3.5 hours). Morphine had a slower onset of action than ROPI, but a stronger analgesic effect of longer duration. The RM showed an earlier onset of action than MOR and had a strong analgesic effect for the 24-hour post-injection period. All treatments caused a significant decrease in total nucleated cells compared with the control, 24 hours after administration. CONCLUSIONS AND CLINICAL RELEVANCE: Morphine alone or in combination with ropivacaine produced a strong analgesic effect of prolonged duration, which may offer pain relief for acute synovitis for at least 24 hours.