Post-fire salvage logging increases restoration costs in a Mediterranean mountain ecosystem

Post-fire salvage logging (i.e. felling and removing burnt trees, often eliminating the remaining woody debris) is a practice routinely performed by forest managers worldwide. In Mediterranean-type ecosystems, salvage logging is considered a measure to reduce future reforestation costs, but this assumption remains largely untested. We made a cost analysis of different management schemes, addressing the immediate post-fire burnt-wood management as well as the costs and success of subsequent reforestation efforts. Two experimental 25-ha plots were established in a burnt pine reforestation of SE Spain, in which three replicates of three post-fire treatments were applied: non-intervention (NI), partial cut plus lopping (PCL; felling and lopping off the branches from most of the trees, leaving all biomass in situ), and salvage logging (SL). After 4?years, a mechanised reforestation was undertaken, and seedling mortality was monitored for 2?years. The cost of all management operations was recorded in situ, and the cost of re-planting the dead seedlings was estimated according to the expenses of previous reforestation. Initial cost of wood management was greatest in SL and zero in NI. Reforestation cost was highest in NI and lowest in SL, and seedling-mortality rates proved lowest in PCL (43?% vs. 51?% and 52?% in SL and NI, respectively). Considering all the post-fire management operations, salvage logging did not provide particular economic advantages for forest restoration, and had an overall cost of 3,436?±?340?€/ha. By contrast, NI and PCL reduced total restoration costs by 50 and 35?%, respectively, and PCL indeed promoted restoration success. We suggest that the full cost of management operations needs to be considered when evaluating the economic implications of post-fire salvage logging.     

Increase in size and nitrogen concentration enhances seedling survival in Mediterranean plantations. Insights from an ecophysiological conceptual model of plant survival

Reduction in size and tissue nutrient concentration is widely considered to increase seedling drought resistance in dry and oligotrophic plantation sites. However, much evidence indicates that increase in size and tissue nutrient concentration improves seedling survival in Mediterranean forest plantations. This suggests that the ecophysiological processes and functional attributes relevant for early seedling survival in Mediterranean climate must be reconsidered. We propose a ecophysiological conceptual model for seedling survival in Mediterranean-climate plantations to provide a physiological explanation of the frequent positive relationship between outplanting performance and seedling size and nutrient concentration. The model considers the physiological processes outlined in the plantation establishment model of Burdett (Can J For Res 20:415–427, 1990), but incorporates other physiological processes that drive seedling survival, such as N remobilization, carbohydrate storage and plant hydraulics. The model considers that seedling survival in Mediterranean climates is linked to high growth capacity during the wet season. The model is for container plants and is based on three main principles, (1) Mediterranean climates are not dry the entire year but usually have two seasons of contrasting water availability; (2) summer drought is the main cause of seedling mortality; in this context, deep and large roots is a key trait for avoiding lethal water stress; (3) attainment of large root systems in the dry season is promoted when seedlings have high growth during the wet season. High growth is achieved when seedlings can divert large amount of resources to support new root and shoot growth. Functional traits that confer high photosynthesis, nutrient remobilization capacity, and non-structural carbohydrate storage promote high growth. Increases in seedling size and nutrient concentration strongly affect these physiological processes. Traits that confer high drought resistance are of low value during the wet season because hinder growth capacity. We provide specific evidence to support the model and finally we discuss its implications and the factors that may alter the frequent increase in performance with increase in seedling size and tissue nutrient concentration.     

Echinococcus multilocularis in dogs from two French endemic areas: no evidence of infection but hazardous deworming practices

The life cycle of the zoonotic parasite Echinococcus multilocularis is predominantly sylvatic, involving foxes as definitive hosts infected by predation of rodents, the intermediate hosts. The North-Eastern French departments of Meuse and Haute-Sa?ne are highly endemic, with an estimated fox prevalence of 41% and 36% respectively. Although most of the parasites' biomass occurs in foxes, domestic dogs can also be infected, leading to a major risk of human infection due to the close proximity of dogs and owners. In the present study, dog faeces were collected after praziquantel treatment provided by veterinarians. In all, 860 faecal samples were collected throughout Meuse (n=493) and Haute-Sa?ne (n=367). Intestinal helminth eggs were isolated from the faeces using a flotation technique and observed by microscopy. Parasite species were identified in samples positive for taeniid eggs by sequence analysis after PCR amplification. To study the factors associated with infestation, each sample was linked to a questionnaire filled in by the dog owners. Taeniid eggs were observed in seven faecal samples (0.8%) but none of them were positive for E. multilocularis. Thus, the apparent prevalence of E. multilocularis in dog populations is lower than 1.00% for Haute-Sa?ne and lower than 0.75% for Meuse. In Haute-Sa?ne, a high proportion of dogs observed suspected preying on rodents were not dewormed monthly. In endemic areas, these dogs must be considered at risk of transmitting E. multilocularis to humans.     

Differences in helminth infections between captive and wild spur-thighed tortoises Testudo graeca in southern Spain: a potential risk of reintroductions of this species

Although the spur-thighed tortoise, Testudo graeca, is one of the most widely distributed species of tortoises, its natural populations are threatened through its whole range. Particularly at south-eastern Spain, the species is mainly threatened by habitat destruction and over-collection, given that this chelonian has been traditionally considered an appreciate pet. As south-eastern Spanish wildlife recovery centers shelter hundreds of captive animals mainly coming from illegal trade or captive-bred, there is a strong debate about what to do with these animals: maintaining them in captivity all along their lives or reintroducing them to wildlife. It is well known that the reintroduction of captive animals supposes a risk for the wild population due to the uncertainty of their genetic origin and to the possible spread of infectious diseases. However, despite the increasing evidence that infectious agents are a potential health hazard for wildlife, little is known about the risk that introduced parasites could suppose for the wild populations of spur-thighed tortoise. The present study investigates for the first time the presence of helminth eggs and worms in faeces from 107 wild and captive individuals collected from mid-March to mid-June 2010, and relates the findings to different environmental and host variables. Sixteen oxyurid species and the ascarid Angusticaecum holopterum were identified. This last nematode and the oxyurid species Tachygonetria palearticus and T. seurati had not been reported in Spanish wild T. graeca previously. The prevalence of oxyurid eggs and worms were 94% and 70%, respectively; while, ascarid eggs and worms were found in 26% and 5% of tortoises, respectively. Ascarid infections affected mostly captive animals and were associated to caparace deformities and symptoms of upper respiratory tract disease (p<0.05). Oxyurid infections were not associated to negative health traits and prevalence increased with age. In free-living tortoises, the distribution of pharingodonid genera also varied according to habitat; moreover, T. longicollis, T. pusilla, T. conica, T. robusta and Mehdiella stylosa where significantly more frequent in wild compared to captive tortoises (p<0.05). Study results highlight important differences in the nematode fauna of captive and free-living tortoises and questions one more time if the reintroductions of captive animals suppose a risk for the wild population since the former ones can harbor and distribute among free populations pathogens like ascarid nematodes.     

Molecular and serological detection of Theileria equi and Babesia caballi in donkeys (Equus asinus) in Brazil

Piroplasmosis in donkeys has been recognized as a serious problem of major economic importance, since the affected animals manifest loss of appetite and decreased working capacity. The present work is aimed at detecting infection or exposure of donkeys in S?o Paulo, Brazil to Theileria (T.) equi and Babesia (B.) caballi using molecular and serological approaches. EDTA-blood and serum samples were collected from 88 donkeys (Equus asinus). From 88 sampled donkeys, 65 (73.86%; 95% confidence interval, PI=63.41, 82.65) and 82 (93.2%; 95% confidence interval, PI=85.75, 97.46) animals showed IgG antibodies to T. equi (by ELISA) and B. caballi (by IFAT), respectively. Twenty-eight (31.81%; 95% confidence interval, PI=22.3, 42.61) and 18 (20.45%; 95% confidence interval, PI=12.6, 30.39) donkeys were positive to T. equi and B. caballi nested PCR assays, respectively. The results indicated that T. equi and B. caballi are prevalent among donkeys in Brazil.     

A new type of pterocarpanquinone that affects Toxoplasma gondii tachyzoites in vitro

Toxoplasma gondii, the agent of Toxoplasmosis, is an obligate intracellular protozoan able to infect a wide range of vertebrate cells, including nonprofessional and professional phagocytes. Therefore, drugs must have intracellular activities in order to control this parasite. The most common therapy for Toxoplasmosis is the combination of sulfadiazine and pyrimethamine. This treatment is associated with adverse reactions, thus, the development of new drugs is necessary. In previous studies, naphthoquinone derivatives showed anti-cancer activity functioning as agents capable of acting on groups of DNA, preventing cancer cells duplication. These derivatives also display anti-parasitic activity against Plasmodium falciparum and Leishmania amazonensis. The derivative pterocarpanquinone tested in this work resulted from the molecular hybridization between pterocarpans and naphtoquinone that presents anti-tumoral and anti-parasitic activities of lapachol. The aim of this work was to determine if this derivative is able to change T. gondii growth within LLC-MK2 cells. The drug did not arrest host cell growth, but was able to decrease the infection index of T. gondii with an IC(50) of 2.5 μM. Scanning and transmission electron microscopy analysis showed morphological changes of parasites including membrane damage. The parasite that survived tended to encyst as seen by Dolichos biflorus lectin staining and Bag-1 expression. These results suggest that pterocarpanquinones are drugs potentially important for the killing and encystment of T. gondii.     

Enrofloxacin is able to control Toxoplasma gondii infection in both in vitro and in vivo experimental models

Currently, toxoplasmosis is treated with sulfadiazine and pyrimethamine. However, this treatment presents several adverse side effects; thus, there is a critical need for the development and evaluation of new drugs, which do not present the same problems of the standard therapy. Enrofloxacin is a fluoroquinolone antibiotic known to control infection against several bacteria in veterinary medicine. Recently, this drug has demonstrated protective effects against protozoan parasites such as Neospora caninum. The present study aimed to determine the effect of enrofloxacin in the control of Toxoplasma gondii infection. For this purpose, human foreskin fibroblast (HFF) cells were infected with T. gondii RH strain and treated with sulfadiazine, penicillin/streptomycin, pyrimethamine, or enrofloxacin. Following treatment, we analyzed the infection index, parasite intracellular proliferation and the number of plaques. Additionally, tissue parasitism and histological changes were investigated in the brain of Calomys callosus that were infected with T. gondii (ME49 strain) and treated with either sulfadiazine or enrofloxacin. Enrofloxacin was able to reduce the infection index, intracellular proliferation and the number of plaques in HFF cells infected by T. gondii in comparison with untreated or penicillin/streptomycin-treated ones. Enrofloxacin was more protective against T. gondii in HFF infected cells than sulfadiazine treatment (P<0.001). In addition, pyrimethamine, enrofloxacin or the associations of sulfadiazine plus pyrimethamine, enrofloxacin plus sulfadiazine or enrofloxacin plus pyrimethamine-treatments were able to reduce the plaque numbers in HFF cells infected by T. gondii when compared to medium, penicillin/streptomycin or sulfadiazine alone. In vivo experiments demonstrated that enrofloxacin diminished significantly the tissue parasitism as well as the inflammatory alterations in the brain of C. callosus infected with T. gondii when compared with untreated animals. Based on our findings, it can be concluded that enrofloxacin is a potential alternative drug for the treatment of toxoplasmosis.     

Thymomas in rabbits: clinical evaluation, diagnosis, and treatment

Thymomas are rarely recorded in rabbits, and the literature includes comparatively few cases. Medical records were reviewed to identify all pet rabbits in which a mediastinal mass was diagnosed between Feb 2007 and Jan 2010. Signalment, history, clinical signs, diagnostic work-up (including laboratory data, diagnostic imaging, and ultrasound-guided fine-needle aspiration of the mediastinal mass), treatment modalities, survival time, and histologic findings were evaluated. Cytologic and/or histopathologic examinations revealed thymomas in all rabbits with mediastinal masses (n=13). Rabbits with thymomas showed clinical signs of dyspnea (76.9%), exercise intolerance (53.9%), and bilateral exophthalmos (46.2%). In seven rabbits the thymoma was removed surgically. Two rabbits were treated conservatively, and four rabbits were euthanized because of their poor clinical condition. The two rabbits that underwent surgery were euthanized 6 mo and 34 mo later. Mediastinal masses in rabbits appear to be more common than previously believed and consist primarily of thymomas rather than thymic lymphomas. Cytology of samples collected by ultrasound-guided fine-needle aspiration is an accurate diagnostic tool for the identification of thymomas in rabbits. Due to a high rate of perioperative mortality, intensive perioperative care and the provision of a low-stress environment are recommended for a successful thoracotomy.     

Accuracy assessment and screening of a dairy herd with paratuberculosis by three different ELISAs

Although the culture of Mycobacterium avium subsp. paratuberculosisis is the gold standard for the diagnosis of paratuberculosis, this bacterium is difficult to grow. In contrast, serological tests like ELISAs are inexpensive, rapid, and easy to perform. The aims of this study were to evaluate the accuracy of three different ELISAs: one with the commercial antigen PPA-3, another one with L5P (a recently described lipopentapeptide), and a third one with an in-house antigen whole cell lysates (WCL) of M. avium (MAA) strain D4ER (Study 1), and to compare them with other tests for paratuberculosis (PTB) diagnosis (Study 2). In Study 1, the sensitivities of the three ELISAs tested were 74.1%, 37% and 74.1%, respectively, whereas their specificities were 98.9%, 100% and 100%, respectively. In Study 2, we compared the three above-mentioned ELISAs with the intradermal reaction test using Avian PPD (PPDa) and fecal culture associated with Ziehl-Neelsen stain and PCR tests, in a dairy herd with 4.6% of cows with clinical signs of PTB. The results showed that fecal samples from 14 cows (16%) were culture-positive and that fecal samples from nine cows (10%) were PPDa-positive. Most of these animals (culture-positive and PPDa-positive) were detected as positive with any of the three ELISAs tested. Serological results showed that 31% of the animals were positive to ELISA-PPA-3, 17% to ELISA-L5P and 42.5% to ELISA-WCL. The combination of these three ELISAs identified 50.6% of the animals as positive in the infected herd. In particular, the results show that the locally developed ELISA seems to be useful for identifying many infected animals in a herd.     

Species and staphylococcal cassette chromosome mec (SCCmec) diversity among methicillin-resistant non-Staphylococcus aureus staphylococci isolated from pigs

While methicillin-resistant Staphylococcus aureus (MRSA) ST398 is known to be widespread in pig farms, few studies have investigated the species diversity and SCCmec types of methicillin-resistant non-S. aureus staphylococci (MRNAS) residing in the nose of pigs. We examined nasal swab samples of 200 pigs originating from 10 Belgian pig farms previously found positive for MRSA ST398. Suspected staphylococcal isolates were subjected to a 16S rRNA-mecA-nuc PCR. Confirmed MRNAS were genotypically identified to the species level and investigated with a SCCmec typing PCR. MRNAS (n=72) were detected on all 10 farms and were carried by 29.5% of the pigs. Seven MRNAS species were found: Staphylococcus epidermidis (38.9%), Staphylococcus sciuri (18.1%), Staphylococcus pasteuri (18.1%), Staphylococcus rostri (12.5%), Staphylococcus warneri (8.3%), Staphylococcus haemolyticus (2.7%) and Staphylococcus hominis (1.4%). SCCmec cassettes were of type IVa (29.2%), type IVc (25%), type III (22.2%), type V (5.6%) or could not be assigned to any of the known types (NT types) (18.1%). Five distinct NT types were found. The predominance of methicillin-resistant S. epidermidis (MRSE) in our samples is remarkable, as MRSE is mainly associated with humans. The finding of three different SCCmec elements (IVa, V, NT type 1) in MRNAS that also prevail or predominate in MRSA ST398 shows that MRNAS might be an important SCCmec reservoir for MRSA in pigs. Yet, the occurrence of multiple other SCCmec types illustrates that further studies are required to understand the presence and spread of SCCmec in methicillin-resistant staphylococci from animals.