The seasonal change, i.e. the marked differences between seasons of low and high productivity, in the abundance of ectosymbionts and the defence intensity of the host against pathogens is a well defined characteristic of temperate zone organisms. Here we investigate the seasonal variation in the uropygial gland size and the abundance of Proctophyllodes feather mites on the wing feathers of house sparrows Passer domesticus in two breeding populations. The size of the uropygial gland varied significantly in male and female house sparrows over the annual cycle. The gland was small during the non‐breeding and mating season, after that it started to grow sharply, reaching its maximum size during breeding. Females had larger gland volumes than males during breeding, and the increase in gland size during breeding was more pronounced in females than in males. The number of feather mites was the lowest during breeding, followed by an increase during moult, and reaching its maximum between the wintering and mating seasons. The absence of a significant relationship between the uropygial gland size and the abundance of feather mites, after controlling for potential confounding variables, supports the view that gland oils do not regulate the number of mites. To investigate further this hypothesis, through a full factorial experimental design we tested the effect of uropygial gland and photoperiod manipulation on the population size and population dynamics of feather mites. The manipulation of uropygial gland had no effect on mites, supporting our observational results. As a result of the experimentally increased day‐length, the abundance of feather mites on wing feathers decreased significantly and more sharply than in the control group, supporting the previous anecdotal evidence about the photosensitivity of these organisms. Using photoperiodic cues, feather mites may respond to seasonal changes that affect their life‐history and population dynamics.
The preen gland is a holocrine sebaceous gland of the avian integument which produces an oily secretion that is spread on the plumage during preening. It has been suggested that birds may defend themselves against feather-degrading bacteria (FDB) and other potential pathogens using preen gland secretions. However, besides some in vitro studies, the in vivo bacterial inhibitory effects of the preen oil on the abundance of feather-associated bacterial species has not yet been studied in passerines. Here we tested the effect of gland removal on the abundance of FDB and other-cultivable bacterial loads (OCB) of male house sparrows (Passer domesticus). Our results did not support earlier results on in vitro antibacterial activity of preen oil against FDB since the absence of the preen gland did not significantly affect their loads related to the control birds. In contrast, we found that preen gland removal led to higher loads of OCB. This result suggests that the antimicrobial spectrum of the preen oil is broader than previously thought and that, by reducing the overall feather bacterial loads, the preen gland could help birds to protect themselves against a variety of potentially harmful bacteria.
Background Canine parvovirus (CPV) is one of the most important pathogens of dogs. Despite vaccination, CPV infections are still ubiquitous in dogs, and the three antigenic variants 2a, 2b and 2c are variously distributed in the canine population worldwide. To date, no information is available on CPV variants circulating in some European countries. The aim of this study was to genetically characterise the CPV detected in ten dogs with clinical signs of acute gastroenteritis in Romania. The presence of Carnivore protoparvovirus 1 DNA was investigated in faecal samples using an end-point PCR targeting the complete VP2 gene and positive amplicons were sequenced and analysed. Results All ten dogs with acute gastroenteritis tested positive to Carnivore protoparvovirus 1 DNA in faecal samples. The identified viruses belonged to CPV-2c type, showed identical sequences of the VP2 gene and were characterised by distinctive amino acid residues in the deduced VP2 protein: 5-glicine (5Gly), 267-tirosine (267Tyr), 324-isoleucine (324Ile) and 370-arginine (370Arg). These distinctive amino acid residues have already been reported in CPV-2c widespread in Asia and occasionally detected in Italy and Nigeria. Conclusions Since CPV-2c with VP2 amino acid residues 5Gly, 267Tyr, 324Ile and 370Arg were never reported before 2013, it can be assumed that this virus is progressively expanding its spread in the world dog population. This study adds new data about the presence of this new virus in Europe and underline worrying questions about its potential impact on the health of the canine population.
Glucocorticoid (GC) hormones are significant regulators of homeostasis. The physiological effects of GCs critically depend on the time of exposure (short vs. long) as well as on their circulating levels (baseline vs. stress-induced). Previous experiments, in which chronic and high elevation of GC levels was induced, indicate that GCs impair both the activity of the immune system and the oxidative balance. Nonetheless, our knowledge on how mildly elevated GC levels, a situation much more common in nature, might influence homeostasis is limited. Therefore, we studied whether an increase in GC level within the baseline range suppresses or enhances condition (body mass, hematocrit and coccidian infestation) and physiological state (humoral innate immune system activity and oxidative balance). We implanted captive house sparrows Passer domesticus with either 60 days release corticosterone (CORT) or control pellets. CORT-treated birds had elevated baseline CORT levels one week after the implantation, but following this CORT returned to its pre-treatment level and the experimental groups had similar CORT levels one and two months following the implantation. The mass of tail feathers grown during the initial phase of treatment was smaller in treated than in control birds. CORT implantation had a transient negative effect on body mass and hematocrit, but both of these traits resumed the pre-treatment values by one month post-treatment. CORT treatment lowered oxidative damage to lipids (malondialdehyde) and enhanced constitutive innate immunity at one week and one month post-implantation. Our findings suggest that a relatively short-term (i.e. few days) elevation of baseline CORT might have a positive and stimulatory effect on animal physiology.
The aim of the present report is to describe a novel successful treatment approach for metaldehyde poisoning in a dog: intravenous lipid emulsion therapy (ILE). A 2.5-month-old female Labrador Retriever was referred to the Emergency Department following deliberate ingestion of a metaldehyde-containing granular bait. Severe continuous tonic-clonic activity, muscle tremors, loss of consciousness, diffuse congestion of the oral mucosa, tachycardia, tachypnoea and nystagmus were observed upon admission. Additional intravenous administration of a 20% lipid emulsion resulted in normalization of the vital signs and complete neurological recovery. To the authors' knowledge, this is the first report describing ILE in the treatment of canine metaldehyde intoxication and the first description of a case of metaldehyde poisoning in a dog in Romania. Considering the severity of the neurological signs and the fact that no specific antidote is known, treatment can be significantly challenging to the veterinary practitioner. This finding should be included in metaldehyde poisoning therapy protocols, especially when severe clinical signs fail to respond to symptomatic treatment.
A real-time polymerase chain reaction (qPCR) is considered the gold standard for the laboratory diagnosis of canine parvovirus (CPV) infection but can only be performed in specialized laboratories. Several point-of-care tests (POCT), detecting CPV antigens in faeces within minutes, are commercially available. The aim of this study was to evaluate eight POCT in comparison with qPCR. Faecal samples of 150 dogs from three groups (H: 50 client-owned, healthy dogs, not vaccinated within the last four weeks; S: 50 shelter dogs, healthy, not vaccinated within the last four weeks; p = 50 dogs with clinical signs of CPV infection) were tested with eight POCT and qPCR. Practicability, sensitivity, specificity, positive (PPV) and negative predictive values (NPV), as well as overall accuracy were determined. To assess the differences between and agreement among POCT, McNemar’s test and Cohen’s Kappa statistic were performed. Specificity and PPV were 100.0% in all POCT. Sensitivity varied from 22.9–34.3% overall and from 32.7–49.0% in group P. VetexpertRapidTestCPVAg® had the highest sensitivity (34.3% overall, 49.0% group P) and differed significantly from the 3 POCT with the lowest sensitivities (Fassisi®Parvo (27.7% overall, 36.7% group P), Primagnost®ParvoH+K (24.3% overall, 34.7% group P), FASTest®PARVOCard (22.9% overall, 32.7% group P)). The agreement among all POCT was at least substantial (kappa >0.80). A positive POCT result confirmed the infection with CPV in unvaccinated dogs, whereas a negative POCT result did not definitely exclude CPV infection due to the low sensitivity of all POCT.
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