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Dive into the research topics where Ralph Eric Thijl Vanstreels is active.

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Featured researches published by Ralph Eric Thijl Vanstreels.


PLOS ONE | 2013

Phenological changes in the southern hemisphere.

Lynda E. Chambers; Res Altwegg; Christophe Barbraud; Phoebe Barnard; Linda J. Beaumont; Robert J. M. Crawford; Joël M. Durant; Lesley Hughes; Marie R. Keatley; Matthew Low; Patrícia C. Morellato; Elvira S. Poloczanska; Valeria Ruoppolo; Ralph Eric Thijl Vanstreels; Eric J. Woehler; Ac Wolfaardt

Current evidence of phenological responses to recent climate change is substantially biased towards northern hemisphere temperate regions. Given regional differences in climate change, shifts in phenology will not be uniform across the globe, and conclusions drawn from temperate systems in the northern hemisphere might not be applicable to other regions on the planet. We conduct the largest meta-analysis to date of phenological drivers and trends among southern hemisphere species, assessing 1208 long-term datasets from 89 studies on 347 species. Data were mostly from Australasia (Australia and New Zealand), South America and the Antarctic/subantarctic, and focused primarily on plants and birds. This meta-analysis shows an advance in the timing of spring events (with a strong Australian data bias), although substantial differences in trends were apparent among taxonomic groups and regions. When only statistically significant trends were considered, 82% of terrestrial datasets and 42% of marine datasets demonstrated an advance in phenology. Temperature was most frequently identified as the primary driver of phenological changes; however, in many studies it was the only climate variable considered. When precipitation was examined, it often played a key role but, in contrast with temperature, the direction of phenological shifts in response to precipitation variation was difficult to predict a priori. We discuss how phenological information can inform the adaptive capacity of species, their resilience, and constraints on autonomous adaptation. We also highlight serious weaknesses in past and current data collection and analyses at large regional scales (with very few studies in the tropics or from Africa) and dramatic taxonomic biases. If accurate predictions regarding the general effects of climate change on the biology of organisms are to be made, data collection policies focussing on targeting data-deficient regions and taxa need to be financially and logistically supported.


PLOS ONE | 2014

Outbreak of avian malaria associated to multiple species of Plasmodium in magellanic penguins undergoing rehabilitation in southern Brazil.

Ralph Eric Thijl Vanstreels; Cristiane K. M. Kolesnikovas; Sandro Sandri; Patricia Silveira; Nayara O. Belo; Francisco Carlos Ferreira Junior; Sabrina Epiphanio; Mário Steindel; Érika Martins Braga; José Luiz Catão-Dias

Avian malaria is a mosquito-borne disease caused by Plasmodium spp. Avian plasmodia are recognized conservation-threatening pathogens due to their potential to cause severe epizootics when introduced to bird populations with which they did not co-evolve. Penguins are considered particularly susceptible, as outbreaks in captive populations will often lead to high morbidity and rapid mortality. We used a multidisciplinary approach to investigate an outbreak of avian malaria in 28 Magellanic penguins (Spheniscus magellanicus) at a rehabilitation center during summer 2009 in Florianópolis, Brazil. Hemosporidian infections were identified by microscopic and molecular characterization in 64% (18/28) of the penguins, including Plasmodium (Haemamoeba) tejerai, Plasmodium (Huffia) elongatum, a Plasmodium (Haemamoeba) sp. lineage closely related to Plasmodium cathemerium, and a Haemoproteus (Parahaemoproteus) sp. lineage closely related to Haemoproteus syrnii. P. tejerai played a predominant role in the studied outbreak and was identified in 72% (13/18) of the hemosporidian-infected penguins, and in 89% (8/9) of the penguins that died, suggesting that this is a highly pathogenic parasite for penguins; a detailed description of tissue meronts and lesions is provided. Mixed infections were identified in three penguins, and involved P. elongatum and either P. tejerai or P. (Haemamoeba) sp. that were compatible with P. tejerai but could not be confirmed. In total, 32% (9/28) penguins died over the course of 16 days despite oral treatment with chloroquine followed by sulfadiazine-trimethoprim. Hemosporidian infections were considered likely to have occurred during rehabilitation, probably from mosquitoes infected while feeding on local native birds, whereas penguin-mosquito-penguin transmission may have played a role in later stages of the outbreak. Considering the seasonality of the infection, rehabilitation centers would benefit from narrowing their efforts to prevent avian malaria outbreaks to the penguins that are maintained throughout summer.


Parasitology International | 2013

Parasitological and new molecular-phylogenetic characterization of the malaria parasite Plasmodium tejerai in South American penguins.

Patricia Silveira; Nayara O. Belo; Gustavo A. Lacorte; Cristiane K. M. Kolesnikovas; Ralph Eric Thijl Vanstreels; Mário Steindel; José Luiz Catão-Dias; Gediminas Valkiūnas; Érika Martins Braga

This study is the first report on mortality of Spheniscus magellanicus, penguin of South America, caused by Plasmodium tejerai, which was identified using morphological and molecular analyses. Blood stages (trophozoites, meronts and gametocytes) were reported and illustrated. The necropsy revealed marked splenomegaly and pulmonary edema, as well as moderate hepatomegaly and hydropericardium. The histopathology revealed the presence of tissue meronts in the macrophages and endothelial cells of multiple organs. The molecular analyses showed 5.6% of genetic divergence in cytochrome b gene between P. tejerai and Plasmodium relictum. Morphology of blood and tissue stages of P. tejerai is similar to P. relictum; the distinction between these two species requires experience in the identification of avian Plasmodium species. Molecular studies associated with reliably identified morphological species are useful for barcoding and comparisons with previous studies of wildlife malaria infections as well as for posterior phylogenetic and phylogeographic studies. S. magellanicus is a new host record of P. tejerai, which is the virulent parasite and worth more attention in avian conservation and veterinary medicine projects in South America.


Zoo Biology | 2010

Impacts of animal traffic on the Brazilian Amazon parrots (Amazona species) collection of the Quinzinho de Barros Municipal Zoological Park, Brazil, 1986-2007.

Ralph Eric Thijl Vanstreels; Rodrigo Hidalgo Friciello Teixeira; Adauto Luis Veloso Nunes; Eliana Reiko Matushima

Eleven species of Amazon parrots (genus Amazona) are known to occur in Brazil, and nest poaching and illegal traffic pose serious conservation threats to these species. When the illegal owners realize these animals are incompatible with their expectations and lifestyle, or when the police arrests traders and owners, these trafficked animals are often considered unfit for release and sent to local zoos and captive breeders. A retrospective survey of animal and necropsy records from 1986 to 2007 was used to evaluate the impacts of animal traffic on the population composition and mortality patterns of Amazon parrots at the Quinzinho de Barros Municipal Zoological Park, Sorocaba, Brazil. Data were obtained for 374 Amazon parrots of ten Brazilian species, and there was evidence that the studied population could be split into two major groups: a majority belonging to the Amazona aestiva species and a minority belonging to the remaining species. In comparison, the animals of the first group were more frequently admitted from traffic-related origins (98 vs. 75%), had a shorter lifespan (median 301 days vs. 848 days) and a higher mortality within the first year postadmission (54 vs. 37%), were less likely to receive expensive treatments, and were more frequently housed off-exhibit. On an average, parrots were found to have a short postadmission lifespan (median 356 days), with 92.5% of the birds dying within their first five years in captivity. The paper discusses the difficult dilemmas these incoming traffic-related animals pose to zoo management and official anti-traffic policies.


International journal for parasitology. Parasites and wildlife | 2015

Epidemiology and molecular phylogeny of Babesia sp. in little penguins Eudyptula minor in Australia

Ralph Eric Thijl Vanstreels; Eric J. Woehler; Valeria Ruoppolo; Peter Vertigan; Nicholas Carlile; David Priddel; Annett Finger; Peter Dann; Kimberly Vinette Herrin; Paul Thompson; Francisco Carlos Ferreira Junior; Érika Martins Braga; Renata Hurtado; Sabrina Epiphanio; José Luiz Catão-Dias

Highlights • We examined blood smears from 263 wild little penguins in southeastern Australia.• Babesia sp. was detected in penguins in New South Wales, Victoria and Tasmania.• True prevalence is estimated between 3.4% and 4.5%.• Babesia sp. from little penguins is closely related to B. poelea and B. uriae.• Babesia infections were assymptomatic.


Biota Neotropica | 2010

Microestrutura de pêlos-guarda de felídeos Brasileiros: considerações para a identificação de espécies

Ralph Eric Thijl Vanstreels; Fernanda do Passo Ramalho; Cristina Harumi Adania

The analysis of cuticle and medulla hair microstructure is a simple and inexpensive technique to identify mammal species for a variety of applications. We studied the guard-hairs of 66 individuals of eight felid species occurring in Brazil (Leopardus colocolo, L.geoffroyi, L.pardalis, L.tigrinus, L.wiedii, Panthera onca, Puma concolor, Puma yagouaroundi), through hair samples collected from anesthetized zoo animals. The microstructure of the guard-hairs was analyzed and described through cuticle impressions and medulla preparations; a blind test was conducted to evaluate the accuracy of species identification. Although distinctive morphological characters could be identified for each species, the subtlety of these characters and the overlap of features among species resulted in a relatively poor accuracy (75%). The identification of pairs or trios of species whose hair has similar morphologies (Group A: L. pardalis, L. tigrinus, L. wiedii; Group B: L. colocolo, L. geoffroyi, P. yagouaroundi; Group C: P. concolor, P. onca) significantly improved accuracy (91%). The identification of Brazilian felids through the microstructure of their hair is challenging and requires careful examination of subtle features, and should be complemented by more accurate techniques and/or be limited mostly to applications where high accuracy is not essential or where a broader taxonomic scale is being evaluated.


Polar Biology | 2014

Investigation of blood parasites of pygoscelid penguins at the King George and Elephant Islands, South Shetlands Archipelago, Antarctica

Ralph Eric Thijl Vanstreels; Flavia R. Miranda; Valeria Ruoppolo; Ana Olívia de Almeida Reis; Erli Schneider Costa; Adriana Rodrigues de Lira Pessôa; João Paulo Machado Torres; Larissa Schmauder Teixeira da Cunha; Roberta da Cruz Piuco; Victor Hugo Valiati; Daniel González-Acuña; Marcelo B. Labruna; Maria Virginia Petry; Sabrina Epiphanio; José Luiz Catão-Dias

Abstract Parasites may adversely affect the breeding success and survival of penguins, potentially hampering the viability of their populations. We examined 161 pygoscelid penguins (3 Pygoscelis adeliae, 98 Pygoscelis antarcticus, and 60 Pygoscelis papua) at the South Shetlands Archipelago during the 2010–2011 summer; blood smears were examined for 64 penguins (2 P. adeliae, 18 P. antarcticus, and 44 P. papua), and a PCR test targeting Haemoproteus sp. and Plasmodium sp. was applied for 37 penguins (2 P. adeliae, 17 P. antarcticus, 19 P. papua). No blood parasites were observed, and all PCR tests were negative, leukocyte profiles were similar to those reported in other studies for wild pygoscelid penguins, and all penguins were in good body condition and had no external signs of disease. One specimen of chewing lice (Austrogoniodes sp.) was recorded in one P. antarcticus at King George Island. Ticks (Ixodes uriae) were not observed on the penguins, but were found on the ground near P. antarcticus nests at King George Island. The absence of avian blood parasites in Antarctic penguins is thought to result from the absence of competent invertebrate hosts in the climatic conditions. Predicted climate changes may redefine the geographic distribution of vector-borne pathogens, and therefore, the occurrence of blood parasites and their invertebrate hosts should be monitored regularly in Antarctic birds, particularly in the northernmost Antarctic Peninsula.


Journal of Wildlife Diseases | 2014

HEALTH EVALUATION AND SURVEY OF ZOONOTIC PATHOGENS IN FREE-RANGING CAPYBARAS (HYDROCHOERUS HYDROCHAERIS)

Rosely Gioia-Di Chiacchio; Fabiola Eloisa Setim Prioste; Ralph Eric Thijl Vanstreels; Terezinha Knöbl; Milton Kolber; Samantha Ive Miyashiro; Eliana Reiko Matushima

Abstract Capybaras (Hydrochoerus hydrochaeris) are the worlds largest rodents and play an epidemiologic role in the transmission of zoonotic pathogens, including the causative agents of Brazilian spotted fever, leptospirosis, and others. We surveyed the health of 31 free-ranging capybaras at the Alberto Löfgren State Park, São Paulo, Brazil using a variety of diagnostic methods. Hematology and serum chemistry were consistent with mild malnutrition and parasitism but did not indicate severe physiologic imbalance or disease. All animals were serologically negative for Rickettsia rickettsii, Leishmania spp., and Trypanosoma sp., but antibodies against rabies virus (71%), Leptospira sp. (26%), and Toxoplasma sp. (23%) were detected. Salmonella sp. was not cultured from fecal samples. Frequently cultured enterobacteria included Escherichia coli (61%), Enterococcus casseiflavus (35%), Enterococcus faecalis (35%), Enterobacter aerogenes (32%), Klebisella pneumoniae (32%), and Serratia marcescens (32%). No potentially pathogenic fungi were cultured from hair samples. Fecal parasitology revealed infection by Protozoophaga sp. (58%), Viannella spp. (23%), Strongyloides spp. (10%), and Ancilostomatidae (10%). A total of 218 ticks was retrieved from the animals: Amblyomma sp. larvae and nymphs (43%), A. dubitatum adults (52%), and A. cajennense adults (5%). The capybaras were free from most potentially zoonotic pathogens evaluated; however, the presence of Amblyomma spp. ticks (potential vectors of Rickettsia spp.) and indirect evidence of exposure to the rabies virus, Leptospira sp., and Toxoplasma sp. warrant the maintenance of public health programs and wildlife health monitoring.


Avian Diseases | 2012

Hematologic reference values for clinically healthy captive golden conures (Guaruba guarouba).

Fabiola Eloisa Setim Prioste; Ticiana Zwarg; Rodrigo Hidalgo Friciello Teixeira; Ralph Eric Thijl Vanstreels; Arnaldo Rocha; Eliana Reiko Matushima

SUMMARY. Golden conures or ararajubas (Guaruba guarouba) are endangered parrots endemic to the Brazilian Amazon forest. Body mass, blood cell counts, and total plasma protein were determined for 70 clinically healthy golden conures captive at zoologic parks and private breeder facilities in Brazil. Hematologic results (mean ± SD) were: Erythrocytes 3.6 ± 0.5 × 106 cells/mm3, hemoglobin 12.8 ± 1.4 g/dl, packed cell volume 46 ± 3.8%, mean corpuscular volume 132 ± 20 fl, mean corpuscular hemoglobin (MCH) 36 ± 5.7 pg, mean corpuscular hemoglobin concentration (MCHC) 28 ± 3.5%, thrombocytes 26.3 ± 9.3 × 103 cells/mm3, leukocytes 11.9 ± 4.5 × 103 cells/mm3, heterophils 6284 ± 2715 cells/mm3, lymphocytes 5473 ± 2408 cells/mm3, monocytes 113 ± 162 cells/mm3, eosinophils 10 ± 42 cells/mm3, basophils 27 ± 64 cells/mm3. Body mass was 254 ± 24.9 g and total plasma protein (TPP) was 3.54 ± 0.58 g/dl. No statistical differences were observed between genders within age groups. Differences between juveniles (J) and adults (A) were identified for TPP (J < A), MCH (J > A), and MCHC (J > A). These results provide reliable reference values for the clinical interpretation of hematologic results for the species. Hematology may be an important tool for population health investigations on free-ranging golden conure populations and will also be essential to survey the health of release candidates in future reintroduction programs.


Onderstepoort Journal of Veterinary Research | 2016

Health evaluation of African penguins ( Spheniscus demersus ) in southern Africa

Nola J. Parsons; Tertius A. Gous; Adam M. Schaefer; Ralph Eric Thijl Vanstreels

The African penguin (Spheniscus demersus) is an endangered seabird that breeds along the coast of Namibia and South Africa, and disease surveillance was identified as a priority for its conservation. Aiming for the establishment of baseline data on the presence of potential pathogens in this species, a comprehensive health assessment (blood smear examination, haematology, biochemistry and serology) was conducted on samples obtained from 578 African penguins at 11 breeding colonies and a rehabilitation centre. There were 68 penguins that were seropositive for at least one of seven pathogens tested: avian encephalomyelitis virus, avian infectious bronchitis virus, avian reovirus, infectious bursal disease virus, Newcastle disease virus, Mycoplasma gallisepticum and Mycoplasma synoviae. All samples were seronegative for avian influenza virus subtypes H5 and H7 and infectious laryngotracheitis virus. The apparent prevalence of Babesia sp. and Borrelia sp. in blood smears was consistent with previous studies. Babesia-infected individuals had a regenerative response of the erythrocytic lineage, an active inflammatory response and hepatic function impairment. These findings indicate that African penguins may be exposed to conservation-significant pathogens in the wild and encourage further studies aiming for the direct detection and/or isolation of these microorganisms.

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Renata Hurtado

University of São Paulo

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Érika Martins Braga

Universidade Federal de Minas Gerais

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Rodolfo Pinho da Silva-Filho

Universidade Federal do Rio Grande do Sul

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