Native species exhibit physiological habituation to invaders: a reason for hope

Animals cope with environmental perturbations through the stress response, a set of behavioural and physiological responses aimed to maintain and/or return to homeostasis and enhance fitness. Vertebrate neuroendocrine axis activation in response to environmental stressors can result in the secretion of glucocorticoids (GCs), whose acute increases may be adaptive, while chronic elevation may be detrimental. Invasive grey squirrels (Sciurus carolinensis) act as a stressor eliciting elevation of GCs in native red squirrels (Sciurus vulgaris). Here we used 6-year data of variation in faecal glucocorticoid metabolite (FGM) concentrations following invasion by grey squirrels in three red squirrel populations, to identify if red squirrels showed physiological habituation to this stressor. The decrease in FGMs over time was more pronounced shortly after invasion and at high densities of grey squirrels while it decreased less strongly and was no longer influenced by the invader density as time since invasion elapsed. At the individual level, FGMs also decreased more markedly as each red squirrel experienced prolonged contact with the invader. Our study provides compelling new data suggesting that native species in the wild can habituate to prolonged contact with invasive species, showing that they may avoid the potentially harmful effects of chronic elevations in GCs.

Trichinellosis in Slovakia - epidemiological situation in humans and animals (2009-2018)

INTRODUCTION

Trichinella spp. are zoonotic parasitic nematodes with almost worldwide distribution. The infection can be transmitted through the foodborne route and can cause serious health problems in infected human patients. It is also an economically important issue due to the high financial cost connected with prevention of the disease.

OBJECTIVE

The study aimed to discover trends in the epidemiological situation in people and animals in Slovakia in 2009-2018.

MATERIAL AND METHODS

Data on human trichinellosis originated from the Public Health Authority of the Slovak Republic, and data on Trichinella infection in animals from the State Veterinary and Food Administration of the Slovak Republic. A seroepidemiological study on 655 voluntary respondents was performed.

RESULTS

Altogether, 29 human cases were reported between 2009-2018, with a maximum of 13 cases in 2011. Males were affected more often (19 cases) than females (10 cases); the average age of patients was 45.1 years. Antibodies to Trichinellawere detected in two sera (0.3%): in a serum from one hunter and one veterinarian. In the monitored period, the average prevalence of Trichinella infection was 9.6% in 2,295 red foxes, and 0.04% in 165,643 wild boars. Three (1.7%) of 178 surveyed brown bears were positive. Within the compulsory monitoring of trichinellosis in domestic pigs, none from a total of 1,632,688 pigs were positive. The presence of three species, Trichinellabritovi, T. spiralis and T. pseudospiralis, was documented, with T. britovi representing 93.9% of identified isolates.

CONCLUSIONS

The study indicates that the prevalence of Trichinella infection has not changed considerably with time in Slovakia, and the risk of human infection outbreaks is connected mainly with the consumption of wild boar meat.

Toxoplasma gondii infection in selected species of free-living animals in Poland

INTRODUCTION AND OBJECTIVE

Free-living animals can play an important role as a reservoir of Toxoplasma gondi;, however, data concerning this issue in Poland are still limited.The aim of study was to assess the occurrence of T. gondii infection by using molecular methods in free-living animals in selected regions of Poland.

MATERIAL AND METHODS

Tissues samples of 396 animals (foxes, muskrats, birds, martens, badgers, polecats, raccoons, minks, raccoon dogs, otters, small rodents and insectivores, and grass snakes were collected from various regions of Poland. After samples digestion, DNA was isolated using QIAmp DNA Mini Kit (Qiagen). DNA extraction from small rodents and insectivores samples was performed without digestion. Next, nested PCR (B1 gene) and, for a part of nested PCR positive amplicons, RFLP PCR, were performed according to the method by Grigg and Boothroyd (2001). The other part of nested PCR positive DNA isolates were genotyped using 5 genetic markers: SAG1, SAG2 (5'- and 3'), SAG3, BTUB and GRA6, based on the method by Dubey et al. (2006). These PCR products were sequenced and compared with the NCBI database using Blast.

RESULTS

In total, in 50 of the 396 examined animals DNA of T. gondii was detected (12.6%). The highest percentages of positive results in PCR was obtained in martens (40.9%) and badgers (38.5%), lower in birds (27.3%) and the lowest in foxes (7.4%). The RFLP and multilocus PCR analysis showed the dominance of T. gondii clonal type II (or II/III).

CONCLUSIONS

The results of this study indicate the frequent T. gondii infection among free-living animals in Poland, especially martens and badgers, which may indirectly indicate that these animals contribute to the spread of the parasite in the sylvatic environment in Poland. The genotyping analysis showed the dominance of T. gondii clonal type II (or II/III).

Diversity of Staphylococcus aureus clones in wild mammals in Aragon, Spain, with detection of MRSA ST130-mecC in wild rabbits

AIMS

To determine the Staphylococcus aureus carriage rate in wild mammals in Aragon, northern Spain, to analyse their antimicrobial resistance phenotype/genotype and to characterize the recovered isolates.

METHODS AND RESULTS

Nasal and rectal swabs of 103 mammals were collected in Aragón during the period 2012-2015. Antimicrobial susceptibility, the presence of antimicrobial resistance genes and virulence factors were investigated. Molecular characterization was carried out by spa, MLST, agr and SCCmec. Staphylococcus aureus were recovered from 23 animals (22%). Four of the 23 S. aureus were methicillin-resistant S. aureus (MRSA). Three MRSA were mecC-positive and were isolated from European rabbits and were typed as t843 (ascribed to CC130). The remaining MRSA was a mecA-carrying isolate from European hedgehog, typed as ST1-t386-SCCmecIVa-agrIII and it harboured the blaZ, erm(C), ant(6)-Ia and aph(3´)-IIIa resistance genes. A high diversity of spa-types was detected among the 19 methicillin-susceptible S. aureus isolates, which showed high susceptibility to the antimicrobials tested. The tst gene and different combinations of staphylococcal enterotoxins were found.

CONCLUSIONS

Staphylococcus aureus were detected in nasal and rectal samples of wild mammals. Wild rabbits could be a reservoir of mecC-MRSA.

SIGNIFICANCE AND IMPACT OF THE STUDY

This work provides information on the presence and characteristics of S. aureus from mammals in a defined geographic region in Spain.

SERUM BIOCHEMISTRY VALUES FOR THE OLROG'S GULL (LARUS ATLANTICUS): A STUDY BASED ON FREE-LIVING INDIVIDUALS

Analysis of serum parameters provides information about body condition, nutritional state, and health status of individuals/species, and has broad application in ecological research and veterinary diagnosis. This study establishes baseline values for serum chemistries of the Olrog's gull (Larus atlanticus). Glucose, urea, uric acid, total protein, globulin, albumin, cholesterol, triglyceride, calcium, and phosphorus concentrations were determined, as was the activity of the following enzymes: alkaline phosphatase, creatine phosphokinase, aspartate aminotransferase, and alanine aminotransferase. Thirty nonbreeding gulls (juvenile and subadult individuals) were captured and studied in Mar Chiquita Reserve (Buenos Aires, Argentina) during the wintering periods 2016 (n = 17) and 2017 (n = 13). In general terms, most values for the parameters reported were in line with those previously described for other seabirds. The year had a significant effect on several of the biochemical parameters evaluated, and the sex had a significant effect on the alkaline phosphatase and calcium. This study has defined the serum biochemical reference signatures for free-ranging Olrog's gulls during the nonbreeding period, and contributes to the knowledge of the overall health status of this threatened and endemic species.

Microbats appear to have adult hippocampal neurogenesis, but post-capture stress causes a rapid decline in the number of neurons expressing doublecortin

A previous study investigating potential adult hippocampal neurogenesis in microchiropteran bats failed to reveal a strong presence of this neural trait. As microchiropterans have a high field metabolic rate and a small body mass, it is possible that capture/handling stress may lead to a decrease in the detectable presence of adult hippocampal neurogenesis. Here we looked for evidence of adult hippocampal neurogenesis using immunohistochemical techniques for the endogenous marker doublecortin (DCX) in 10 species of microchiropterans euthanized and perfusion fixed at specific time points following capture. Our results reveal that when euthanized and perfused within 15 min of capture, abundant putative adult hippocampal neurogenesis could be detected using DCX immunohistochemistry. Between 15 and 30 min post-capture, the detectable levels of DCX dropped dramatically and after 30 min post-capture, immunohistochemistry for DCX could not reveal any significant evidence of putative adult hippocampal neurogenesis. Thus, as with all other mammals studied to date apart from cetaceans, bats, including both microchiropterans and megachiropterans, appear to exhibit substantial levels of adult hippocampal neurogenesis. The present study underscores the concept that, as with laboratory experiments, studies conducted on wild-caught animals need to be cognizant of the fact that acute stress (capture/handling) may induce major changes in the appearance of specific neural traits.