The impact of animal age, bacterial coinfection, and isolate pathogenicity on the shedding of Porcine reproductive and respiratory syndrome virus in aerosols from experimentally infected pigs

The objective of this study was to evaluate the role of different variables (animal age, bacterial coinfection, and isolate pathogenicity) on the shedding of Porcine reproductive and respiratory syndrome virus (PRRSV) in aerosols. Animals were grouped according to age (2 versus 6 mo) and inoculated with a PRRSV isolate of either low (MN-30100) or high (MN-184) pathogenicity. Selected animals in each group were also inoculated with Mycoplasma hyopneumoniae. The pigs were anesthetized and aerosol samples (1000 breaths/sample) collected on alternating days from 1 to 21 after PRRSV inoculation. The results indicated that animal age (P = 0.09), M. hyopneumoniae coinfection (P = 0.09), and PRRSV isolate pathogenicity (P = 0.15) did not significantly influence the concentration of PRRSV in aerosols. However, inoculation with the PRRSV MN-184 isolate significantly increased the probability of aerosol shedding (P = 0.00005; odds ratio = 3.22). Therefore, the shedding of PRRSV in aerosols may be isolate-dependent.     

Comparison of plasma histamine levels after intravenous administration of hydromorphone and morphine in dogs

This study compared plasma histamine concentrations, behavioral and cardiovascular parameters following intravenous administration of hydromorphone and morphine in conscious dogs. Five adult female dogs received a 15-sec bolus injection of saline, hydromorphone (0.1 and 0.2 mg/kg) or morphine (0.5 and 1.0 mg/kg) randomly at weekly intervals. Blood samples were collected from the jugular vein before and at 1, 2, 5, 15, 30, 60 and 120 min after drug administration. Plasma histamine concentration, noninvasive oscillometric blood pressure, heart rate and rhythm were evaluated. Data were analyzed with repeated measures anova and Tukey-Kramer post hoc test with a 5% significance level. Median plasma histamine increased significantly only after the higher dose of morphine. Maximum plasma histamine measured was 0.8 ng/mL after saline and, after the lower and higher doses, respectively, 10.2 and 9.7 ng/mL for hydromorphone, and 440 and 589 ng/mL for morphine. One dog became hypotensive immediately after receiving the highest dose of morphine. Occasional ventricular premature contractions occurred in one dog after both opioids and dosages. No dogs vomited or defecated, but all salivated profusely with both opioids. Neuroexcitation occurred in four dogs following each opioid. In conclusion, intravenous hydromorphone induced minimal histamine release and was well tolerated by these conscious healthy dogs.     

Use of a soluble epoxide hydrolase inhibitor as an adjunctive analgesic in a horse with laminitis

HistoryA 4‐year old, 500 kg Thoroughbred female horse diagnosed with bilateral forelimb laminitis and cellulitis on the left forelimb became severely painful and refractory to non‐steroidal anti‐inflammatory therapy (flunixin meglumine on days 1, 2, 3 and 4; and phenylbutazone on days 5, 6 and 7) alone or in combination with gabapentin (days 6 and 7).Physical examinationPain scores assessed independently by three individuals with a visual analog scale (VAS; 0 = no pain and 10 = worst possible pain) were 8.5 on day 6, and it increased to 9.5 on day 7. Non‐invasive blood pressure monitoring revealed severe hypertension.ManagementAs euthanasia was being considered for humane reasons, a decision was made to add an experimental new drug, trans‐4‐{4‐[3‐(4‐Trifluoromethoxy‐phenyl)‐ureido]‐cyclohexyloxy}‐benzoic acid (t‐TUCB), which is a soluble epoxide hydrolase (sEH) inhibitor, to the treatment protocol. Dose and frequency of administration were selected based on the drug potency against equine sEH to produce plasma concentrations within the range of 30 nmol L^?1 and 2.5 μmol L^?1. Pain scores decreased sharply and remarkably following t‐TUCB administration and blood pressure progressively decreased to physiologic normal values. Plasma concentrations of t‐TUCB, measured daily, were within the expected range, whereas phenylbutazone and gabapentin plasma levels were below the suggested efficacious concentrations.Follow upNo adverse effects were detected on clinical and laboratory examinations during and after t‐TUCB administration. No new episodes of laminitis have been noted up to the time of writing (120 days following treatment).ConclusionsInhibition of sEH with t‐TUCB was associated with a significant improvement in pain scores in one horse with laminitis whose pain was refractory to the standard of care therapy. No adverse effects were noticed. Future studies evaluating the analgesic and protective effects of these compounds in painful inflammatory diseases in animals are warranted.     

Insecticide selectivity and behavioral response of the earwig Doru luteipes

Insecticide lethal and sub-lethal effects on non-target species are a focus in pest management programs. However, such studies are usually centered in relatively few groups of natural enemies of insect pests. Earwigs, although insect pest predators of key importance in Neotropical maize fields, have received very little attention. The earwig Doru luteipes (Sccuder) (Dermaptera: Forficulidae) is one of the main predators of the fall armyworm Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae). Both species were subjected to toxicity and selectivity studies with the insecticides chlorantraniliprole, chlorfenapyr, chlorpyrifos, λ-cyhalothrin, deltamethrin, etofenprox, methomyl and spinosad. The behavioral locomotory response of D. luteipes to these compounds was also assessed. Concentration-response bioassays indicated very low potency of chlorantraniliprole (>550,000× less toxic), followed by spinosad (>3,500× less toxic) and etofenprox (>1,100× less toxic) as compared to chlorpyrifos, the most toxic insecticide studied against this earwig species. These same three compounds exhibited the highest selectivity when comparing the earwig with its prey, the fall armyworm. Time-response bioassays using the insecticide label rates recommended against the fall armyworm confirmed the high selectivity of chlorantraniliprole and etofenprox, in addition to deltamethrin and methomyl. Again chlorpyrifos exhibited the lowest levels of selectivity. Exposure of the earwig to insecticide-treated surfaces indicated that spinosad reduced the locomotory activity of the adults probably increasing their insecticide exposure, while they avoided chlorfenapyr-, etofenprox-, and chlorpyrifos-treated surfaces. Chlorantraniliprole and etofenprox seem the most promising compounds for use against S. frugiperda whilst preserving populations of D. luteipes.