Multidrug resistance in pathogenic Escherichia coli isolates from urinary tract infections in dogs, Spain.

Escherichia coli (E. coli) is a pathogen frequently isolated in cases of urinary tract infections (UTIs) in both humans and dogs and evidence exists that dogs are reservoirs for human infections. In addition, E. coli is associated to increasing antimicrobial resistance rates. This study focuses on the analysis of antimicrobial resistance and the presence of selected virulence genes in E. coli isolates from a Spanish dog population suffering from UTI. This collection of isolates showed an extremely high level of phenotypic resistance to 1st-3rd generation cephalosporins, followed by penicillins, fluoroquinolones and amphenicols. Apart from that, 13.46% of them were considered extended-spectrum beta-lactamase producers. An alarmingly high percentage (71.15%) of multidrug resistant isolates were also detected. There was a good correlation between the antimicrobial resistance genes found and the phenotypic resistance expressed. Most of the isolates were classified as extraintestinal pathogenic E. coli, and two others harbored virulence factors related to diarrheagenic pathotypes. A significant relationship between low antibiotic resistance and high virulence factor carriage was found, but the mechanisms behind it are still poorly understood. The detection of high antimicrobial resistance rates to first-choice treatments highlights the need of constant antimicrobial resistance surveillance, as well as continuous revision of therapeutic guidelines for canine UTI to adapt them to changes in antimicrobial resistance patterns.

Identification of Sarcocystis spp. in Slaughtered Sheep from Spain and Evaluation of Bradyzoite Viability after Freezing.

Sarcocystis spp. are complex apicomplexan parasites that cause a substantial economic impact on livestock used for meat production. These parasites are present worldwide. Our study aimed to identify Sarcocystis species affecting sheep meat in southern-central Spain and to evaluate the effectiveness of freezing for parasite inactivation. A total of 210 condemned samples of sheep meat were thoroughly assessed grossly and microscopically; the presence of macro- and microcysts was confirmed. The samples were then frozen at -20 °C for various time intervals (24, 48, 72, 96, 120, and 144 h) and compared with untreated samples. Bradyzoites were isolated through pepsin digestion for subsequent molecular analysis and viability assessment, employing trypan blue and double fluorescence staining techniques. Our measurements confirmed the presence of S. tenella, S. gigantea, and S. medusiformis in Spanish domestic sheep. Freezing for 96 to 144 h resulted in a significant reduction in parasite viability, with a robust correlation observed between the two staining methods. Both stains effectively measured the viability of Sarcocystis, thereby promising future advances in meat safety.

Peripheral neuropathy caused by fenugreek (Trigonella foenum-graecum) straw intoxication in cattle and experimental reproduction in sheep and goats.

Trigonella foenum-graecum (fenugreek) is a legume widely used as a food supplement in humans and less frequently in ruminants. Toxicity has been described sporadically in ruminants grazing mature fenugreek plants or stubble; however, the pathological features are unclear. This report describes a natural outbreak of intoxication in cattle fed fenugreek straw and the experimental reproduction using 8 sheep and 8 goats. Affected cattle presented clinical signs approximately 1 month after consuming the straw and 100 of 400 cattle (25%) were affected, of which 60 of 100 (60%) died or were euthanized. Clinical signs were characterized by proprioceptive positioning defects with abnormal postures and weakness of hindlimbs. Forelimbs were also affected in severely affected animals, and cattle became recumbent. Locomotion was characterized by trembling, and some cattle showed high-stepping movements of their forelimbs and knuckled over in their fetlocks. Experimental intoxication induced clinical signs only in sheep and were similar to cattle, although with signs starting in the forelegs. Gross and microscopic lesions were similar in spontaneous and experimental intoxications. Macroscopic changes corresponded with muscular hemorrhages and edema, mainly surrounding the peripheral nerves. Microscopic examination only demonstrated lesions in the distal peripheral nerves, which included edema, hemorrhages, and Wallerian degeneration. Neurofilament immunohistochemistry revealed altered axon labeling and S100 showed a decrease in myelin intensity and loss of its typical compact arrangement around axons. Biochemical and hematological abnormalities included elevated levels of muscle and liver enzymes and thrombocytopenia. These findings indicate that fenugreek straw induces peripheral neuropathy in cattle and sheep, but not in goats.

Atypical Lesions in Canine Leishmaniosis: Description of New Cases.

Pathological characteristics are well described in canine leishmaniosis (CanL). However, atypical lesions that can be confused with other pathologies or trigger unusual clinical signs are sporadically reported. Atypical lesions were observed during routine postmortem examination in three Leishmania-infected dogs and samples were taken for histopathological and immunohistochemical studies. Clinical signs, biochemical parameters, level of antibodies, and parasite detection by PCR were also evaluated. Atypical lesions were found in the peritoneal cavity, liver, and spleen. Splenomegalia and hepatomegalia were observed in all dogs. In addition, multifocal dark to white nodules of variable size were observed in the peritoneal cavity, liver, and spleen of one dog and in the spleen of the other two dogs. One dog presented diffuse irregular whitish lines with a threadlike appearance and another an intense fibrotic depression in the intermediate lobe. Microscopically, an intense granulomatous inflammation with abundant macrophages, a variable number of lymphocytes, and a low to moderate number of parasites was observed. This study represents the first description of granulomatous peritonitis associated with Leishmania in dogs. It also shows atypical macroscopic expression of hepatitis in CanL. In the absence of an adequate clinical history and laboratory analyses, certain lesions observed in CanL could admit alternative diagnoses.

Characterization of lesions in the temporal muscle and the male reproductive system (epididymis and testicle) of dogs experimentally infected with Leishmania infantum with different clinical stages.

Leishmaniosis is a zoonotic disease with a very complex pathogenesis modulated by the interaction between the parasite, the vector and the host. Although the pathological characteristics have been extensively studied in the typically affected organs, some locations such as muscles and reproductive organs have been less studied. The objective of this study was to evaluate the presence of lesions in the temporal muscle and the male reproductive organs (testicle and epididymis) and correlate their characteristics with the presence of the parasite and with the clinical status of the dogs. The temporal muscle was studied in 25 infected beagle dogs (nine females and 16 males) and five uninfected control dogs (two females and three males) and the testicle and epididymis in the 19 males. Dogs were euthanized one year after infection and clinical signs, anti-Leishmania serum antibodies, and lymph node parasite load were assessed. Muscular and reproductive lesions were characterized by H&E and immunohistochemistry (IHC). The presence of the parasite in the lesions was evaluated using IHC and molecular techniques. Myositis was observed in 72% (18/25) of the dogs and was characterized by lymphoplasmacytic or histiocytic lesions. Mild and severe lesions were detected, the latter being statistically associated with the presence of the parasite and with the clinical status of the dogs. Orchitis was observed in 50% (8/16) of the dogs and was mainly mild and lymphoplasmacytic. No statistical relationship was found between testicular lesions and the presence of the parasite or the clinical status. Epididymitis was observed in 87.5% (14/16) of the dogs, and the lesions were often infiltrated by numerous histiocytes and neutrophils. Epididymal lesions were statistically associated with the clinical status of the dogs and with the presence of the parasite in the lesions. IgG and IgM immunoglobulins were found in all lesions, suggesting a local immune response with reactivation of the infection. Leishmania was more frequently detected in severe and histiocytic lesions, although some lesions had no detectable parasites. These results have shown that lesions in the temporal muscle, epididymis, and testicles are common in dogs infected by Leishmania infantum and that dogs may show a different response to infection. This response is characterized by varying degrees of cellular and immune responses associated with a variable presence of the parasite.

A re-appraisal of the ENSO response to volcanism with paleoclimate data assimilation.

The potential for explosive volcanism to affect the El Niño-Southern Oscillation (ENSO) has been debated since the 1980s. Several observational studies, based largely on tree-ring proxies, have since found support for a positive ENSO phase in the year following large eruptions. In contrast, recent coral data from the heart of the tropical Pacific suggest no uniform ENSO response to explosive volcanism over the last millennium. Here we leverage paleoclimate data assimilation to integrate both tree-ring and coral proxies into a reconstruction of ENSO state, and re-appraise this relationship. We find only a weak statistical association between volcanism and ENSO, and identify the selection of volcanic events as a key variable to the conclusion. We discuss the difficulties of conclusively establishing a volcanic influence on ENSO by empirical means, given the myriad factors affecting the response, including the spatiotemporal details of the forcing and ENSO phase preconditioning.

Comparative Study of Real-Time PCR (TaqMan Probe and Sybr Green), Serological Techniques (ELISA, IFA and DAT) and Clinical Signs Evaluation, for the Diagnosis of Canine Leishmaniasis in Experimentally Infected Dogs.

Canine leishmaniasis (CanL) diagnosis is not fully resolved. Currently, two specific methodologies are in continuous development, the detection of the parasite DNA or RNA in target organs and the detection of specific antibodies against Leishmania sp. For a correct diagnosis, it has been shown that the joint use of this type of test is necessary. In this work, a Sybr Green and a TaqMan Probe based on real time PCRs (qPCR) was performed for the detection of Leishmania sp. in order to correlate the results with clinicopathological and serological evaluations (IFA, ELISA and DAT) to propose an optimal biological sample to be used to detect the parasite in both early and late stages of the infection. A total of four samples were processed: conjunctival swabs, popliteal lymph node aspirates, bone marrow aspirates, and peripheral blood from experimentally infected dogs belonging to a larger study. Our results indicated that a single non-invasive sample (conjunctival swab) and the application of both types of qPCR would be reliable for determining Leishmania infection as well as the disease stage in dogs, thus avoiding bone marrow, lymph node aspirate or blood samples collection.

Different climate sensitivity for radial growth, but uniform for tree-ring stable isotopes along an aridity gradient in Polylepis tarapacana, the world's highest elevation tree species.

Tree growth is generally considered to be temperature limited at upper elevation treelines, yet climate factors controlling tree growth at semiarid treelines are poorly understood. We explored the influence of climate on stem growth and stable isotopes for Polylepis tarapacana Philipi, the world's highest elevation tree species, which is found only in the South American Altiplano. We developed tree-ring width index (RWI), oxygen (δ18O) and carbon (δ13C) chronologies for the last 60 years at four P. tarapacana stands located above 4400 m in elevation, along a 500 km latitude aridity gradient. Total annual precipitation decreased from 300 to 200 mm from the northern to the southern sites. We used RWI as a proxy of wood formation (carbon sink) and isotopic tree-ring signatures as proxies of leaf-level gas exchange processes (carbon source). We found distinct climatic conditions regulating carbon sink processes along the gradient. Current growing-season temperature regulated RWI at northern-wetter sites, while prior growing-season precipitation determined RWI at arid southern sites. This suggests that the relative importance of temperature to precipitation in regulating tree growth is driven by site water availability. By contrast, warm and dry growing seasons resulted in enriched tree-ring δ13C and δ18O at all study sites, suggesting that similar climate conditions control carbon-source processes along the gradient. Site-level δ13C and δ18O chronologies were significantly and positively related at all sites, with the strongest relationships among the southern drier stands. This indicates an overall regulation of intercellular carbon dioxide via stomatal conductance for the entire P. tarapacana network, with greater stomatal control when aridity increases. This manuscript also highlights a coupling (decoupling) between physiological processes at leaf level and wood formation as a function of similarities (differences) in their climatic sensitivity. This study contributes to a better understanding and prediction of the response of high-elevation Polylepis woodlands to rapid climate changes and projected drying in the Altiplano.

Neutrophil Gelatinase-Associated Lipocalin (NGAL) Is Related with the Proteinuria Degree and the Microscopic Kidney Findings in Leishmania-Infected Dogs.

Early diagnosis of renal damage in Leishmania infected dogs may allow appropriate treatments and prevent some deaths. This study investigates neutrophil gelatinase-associated lipocalin (NGAL) as a biomarker of kidney disease in dogs experimentally infected with Leishmania infantum. Serum, urine, and kidney samples were collected from 30 infected beagle dogs and six uninfected control dogs. Based on proteinuria and azotemia values, dogs were initially classified. NGAL was measured in urine and serum samples. Then, the urinary NGAL to creatinine ratio (uNGAL/C) was calculated. Kidney samples were taken for histopathological studies, and the dogs were classified according to the severity of glomerular and tubulointerstitial lesions. In Leishmania-infected dogs, the uNGAL/C was significantly higher in proteinuric non-azotemic dogs compared with non-proteinuric non-azotemic dogs (p = 0.038). Serum NGAL (sNGAL) concentration did not differ between groups. Microscopic studies revealed several degrees of glomerulonephritis and slight focal lymphoplasmacytic interstitial nephritis in 89% and 55% of infected dogs, respectively. Urinary protein to creatinine ratio (UPC) and uNGAL/C were significantly higher in dogs with affected glomeruli compared to infected dogs without renal lesions (p = 0.045 and p = 0.043, respectively). The results show that uNGAL/C correlates with proteinuria and the presence of moderate glomerular lesions in non-azotemic dogs experimentally infected with L. infantum.

Six hundred years of South American tree rings reveal an increase in severe hydroclimatic events since mid-20th century.

South American (SA) societies are highly vulnerable to droughts and pluvials, but lack of long-term climate observations severely limits our understanding of the global processes driving climatic variability in the region. The number and quality of SA climate-sensitive tree ring chronologies have significantly increased in recent decades, now providing a robust network of 286 records for characterizing hydroclimate variability since 1400 CE. We combine this network with a self-calibrated Palmer Drought Severity Index (scPDSI) dataset to derive the South American Drought Atlas (SADA) over the continent south of 12°S. The gridded annual reconstruction of austral summer scPDSI is the most spatially complete estimate of SA hydroclimate to date, and well matches past historical dry/wet events. Relating the SADA to the Australia-New Zealand Drought Atlas, sea surface temperatures and atmospheric pressure fields, we determine that the El Niño-Southern Oscillation (ENSO) and the Southern Annular Mode (SAM) are strongly associated with spatially extended droughts and pluvials over the SADA domain during the past several centuries. SADA also exhibits more extended severe droughts and extreme pluvials since the mid-20th century. Extensive droughts are consistent with the observed 20th-century trend toward positive SAM anomalies concomitant with the weakening of midlatitude Westerlies, while low-level moisture transport intensified by global warming has favored extreme rainfall across the subtropics. The SADA thus provides a long-term context for observed hydroclimatic changes and for 21st-century Intergovernmental Panel on Climate Change (IPCC) projections that suggest SA will experience more frequent/severe droughts and rainfall events as a consequence of increasing greenhouse gas emissions.

Antimicrobial resistance among canine enteric Escherichia coli isolates and prevalence of attaching-effacing and extraintestinal pathogenic virulence factors in Spain.

The aim of this study was to estimate the prevalence of antimicrobial resistance (AMR) in Escherichia coli from a dog population in Spain and assess specific virulence factors. Susceptibility to 22 antimicrobials was tested along with the production of extended-spectrum ß-lactamases (ESBLs) and AmpC in faecal isolates from 100 dogs. Virulence-related genes associated with attaching and effacing E. coli (eae, Stx1, Stx2) and extraintestinal pathogenic E. coli - ExPEC - (papC, hlyA and cnf1) were detected by PCR. At least one kind of AMR was observed in 73% of the isolates. The highest prevalences corresponded to penicillin (45%), aminoglycoside (40%) and non-extended spectrum cephalosporin (39%) classes. Multidrug resistance (MDR) was observed in 53.4% of the resistant isolates. No resistance to colistin was found. Production of ESBL/AmpC enzymes was detected in 5% of E. coli. Shiga toxin-producing E. coli were not observed, enteropathogenic E. coli were identified in only 12% of them, and ExPEC were found in 25%. Dog faeces can be a source of E. coli strains potentially presenting a threat to humans through their virulence factors or AMR. The non-hygienic keeping of animals may increase the risk of colonisation of such pathogens in humans.

Antimicrobial Susceptibilities and Phylogenetic Analyses of Enterococcus hirae Isolated from Broilers with Valvular Endocarditis.

Enterococcus hirae is a zoonotic Enterococcus species that causes opportunistic infections in both humans and animals and can be transmitted by contact with animals or through contaminated food. The aim of this study was to investigate the importance of E. hirae in broilers with endocarditis, as well as the antimicrobial resistance patterns and genetic relatedness of the isolates. A total of 477 three- to five-week-old broilers were studied during five fattening periods on a farm with mortality due to endocarditis. Endocarditis was observed in 27 chickens (5.66%), and samples were taken for pathological, microbiological, and molecular studies. Lesions were mainly found in the right atrioventricular valve and corresponded with a fibrinous endocarditis. Enterococcus hirae was identified in all cases. Pulsed-field gel electrophoresis results showed clonality among some isolates, with one pulsotype harboring 11 isolates that were found throughout the study. Most of the isolates showed multi-drug-resistant phenotypes. These results confirm that E. hirae is a significant cause of endocarditis in broilers, and suggest that broilers may be important carriers of antimicrobial-resistant E. hirae that might enter into the food chain.

Susceptibilidad antimicrobiana y análisis filogenético de Enterococcus hirae aislados de pollos de engorde con endocarditis valvular. Enterococcus hirae es una especie zoonótica de enterococo que provoca infecciones oportunistas en el hombre y en los animales y que puede transmitirse mediante el contacto con animales o a través de alimentos contaminados. El objetivo de este estudio fue la investigación de la importancia de E. hirae en pollos de engorde con endocarditis, así como el estudio de sus patrones de resistencia antimicrobiana y la relación genética entre los aislados. Se estudiaron 477 pollos de engorde de tres a cinco semanas de edad, durante cinco periodos de engorde, en una granja con historial de muertes por endocarditis. Se detectó endocarditis en 27 pollos (5.66%) y se recolectaron muestras para estudios histopatológicos, microbiológicos y moleculares. Las lesiones se observaron principalmente en la válvula atrioventricular derecha, correspondiendo con una endocarditis fibrinosa. En todos los casos se identificó E. hirae. Mediante electroforesis en gel de campo con pulsaciones se detectó clonalidad en algunos aislados, con once aislados agrupados en un pulsotipo, los cuales fueron detectados a lo largo de todo el estudio. La mayoría de los aislados presentaban fenotipos multirresistentes a varios antibióticos. Estos resultados confirman que E. hirae es una causa importante de endocarditis en pollos de engorde y que estos pueden ser portadores importantes de cepas multirresistentes de E. hirae, las cuales podrían entrar en la cadena alimentaria.

Preliminary studies on isolates of Clostridium difficile from dogs and exotic pets.

BACKGROUND: Clostridium difficile infection (CDI) is recognised as an emerging disease in both humans and some animal species. During the past few years, insights into human CDI epidemiology changed and C. difficile is also considered as an emerging community-acquired pathogen. Certain ribotypes (RT) are possibly associated with zoonotic transmission. The objective of this study was to assess the presence of C. difficile in a population of pets and to characterise the isolates. RESULTS: Faecal samples from a total of 90 diarrhoeic dogs and 24 from exotic animal species (both diarrhoeic and non-diarrhoeic) were analysed. Clostridium difficile was isolated from 6 (6.7%) dogs and one reptile sample (4.2%). Four (66.7%) of the six dog strains were capable of producing toxins. Four known different RTs were detected in dogs (010, 014, 123 and 358) and a new one was found in a faecal sample of an exotic animal. This new RT isolate was negative for all toxin genes tested and belonged to sequence type 347 which has been proposed as a Clade-III member. Importantly, two dog strains showed a stable resistance to metronidazole (initial MIC values: 128 and 48 µg/ml). CONCLUSIONS: The results obtained in this study suggest the implementation of antimicrobial susceptibility surveillance programs to assess the prevalence of metronidazole resistance in dogs; molecular studies to elucidate C. difficile metronidazole resistance mechanisms are warranted. Based on the similarity between the ribotypes observed in dogs and those described in humans, the zoonotic transmission should be further explored. Furthermore, exotic animals have shown to harbor uncommon C. difficile strains which require further genomic studies.

[Cedrela odorata (Meliaceae) potential for dendrochronological studies in the Selva Central of Perú]. / Potencialidad de Cedrela odorata (Meliaceae) para estudios dendrocronológicos en la selva central del Perú.

Despite the progress made during the past 20 years, searching dendrochronological potential in tropical and subtropical tree species, tropical dendrochronology, is still in a development stage. The aim of this research was to determine the potential of C. odorata for dendrochronological studies in the Selva Central of Perú. The tree-ring anatomical characteristics were carefully examined and we were able to develop a 215 year (1795-2 009) tree-ring chronology and correlate it with precipitation records. The tree-ring chronology was developed based on 47 series of 27 trees. Tree rings are clearly delimited by large pore diameters in earlywood and small ones in latewood associated with marginal and paratracheal parenchyma. The tree-ring chronology was related to precipitation records from Satipo and significant correlations were found with the previous rainy season and late dry season of the current growth period. Moreover, we found close relationship between tree growth and total precipitations of the hydrological period (December to September) for the interval 1990-2009. These results demonstrate the influence of rainfall at different stages of C. odorata radial growth. The good discrimination of annual rings, strong relationship with precipitation, the wide range and longevity of trees (200 years) make C. odorata a very promising species for dendrochronological studies in tropical and subtropical forest of America.

Potencialidad de Cedrela odorata (Meliaceae) para estudios dendrocronológicos en la selva central del Perú / Cedrela odorata (Meliaceae) potential for dendrochronological studies in the Selva Central of Perú

Despite the progress made during the past 20 years, searching dendrochronological potential in tropical and subtropical tree species, tropical dendrochronology, is still in a development stage. The aim of this research was to determine the potential of C. odorata for dendrochronological studies in the Selva Central of Perú. The tree-ring anatomical characteristics were carefully examined and we were able to develop a 215 year (1 795-2 009) tree-ring chronology and correlate it with precipitation records. The tree-ring chronology was developed based on 47 series of 27 trees. Tree rings are clearly delimited by large pore diameters in earlywood and small ones in latewood associated with marginal and paratracheal parenchyma. The tree-ring chronology was related to precipitation records from Satipo and significant correlations were found with the previous rainy season and late dry season of the current growth period. Moreover, we found close relationship between tree growth and total precipitations of the hydrological period (December to September) for the interval 1 990-2 009. These results demonstrate the influence of rainfall at different stages of C. odorata radial growth. The good discrimination of annual rings, strong relationship with precipitation, the wide range and longevity of trees (200 years) make C. odorata a very promising species for dendrochronological studies in tropical and subtropical forest of America.

En este trabajo determinamos el potencial de Cedrela odorata para estudios dendrocronológicos en la Selva Central del Perú. Para ello, analizamos las características anatómicas que definen los anillos de crecimiento, desarrollamos una cronología de ancho de anillos y relacionamos el crecimiento de los árboles con los registros de precipitación. La cronología de ancho de anillos está compuesta por 47 series de 27 árboles y cubre el período 1795-2009. Los anillos están claramente delimitados por porosidad semicircular, asociados a bandas de parénquima marginal y paratraqueal. El crecimiento de los árboles estuvo relacionado con las precipitaciones de la estación lluviosa previa y con las de finales de la estación seca del corriente período de crecimiento. Así mismo, observamos una estrecha relación entre el crecimiento y las precipitaciones totales, considerando el ciclo hidrológico de diciembre a setiembre, para el periodo 1990-2009. Estos resultados indican la influencia de las precipitaciones en el crecimiento radial de C. odorata. La buena discriminación de los anillos anuales, la fuerte relación con la precipitación, el amplio rango de distribución y la longevidad de los árboles, hacen de C. odorata una especie promisoria para estudios dendrocli-matológicos y dendroecológicos en los bosques tropicales y subtropicales de América.

Influence of precipitation pulses on long-term Prosopis ferox dynamics in the Argentinean intermontane subtropics.

Biological processes in arid communities are associated with episodic precipitation pulses. We postulate that annual to decadal-scale precipitation pulses modulate the dynamics of the intermontane Prepuna woodlands. To study this hypothesis, we have assessed the influence of precipitation pulses on the rates of growth and survival of Prosopis ferox in the Prepuna woodlands during the past century. Tree ages from several P. ferox stands were used to reconstruct the establishment patterns at each sampling site. Ring-width chronologies provided the basis to assess the influence of annual versus multiannual precipitation pulses on radial growth and establishment over time. Both the radial growth and the stand dynamics of P. ferox at the regional scale were found to be largely modulated by climate, with precipitation the dominant factor influencing interannual variations in P. ferox ring-widths. Our analysis of dendrochronological dating data on 885 individuals of P. ferox revealed a period of abundant establishment from the mid-1970s to beginning of 1990 s, which is coincident with an interval of remarkable above-average precipitation. However, tree-growth and establishment patterns at the local scale in the Prepuna also reflected land-use changes, particularly long-term variations in livestock intensity. The P. ferox dynamics documented here substantiates the hierarchical concept of "resource-pulse" in dry ecosystems, with precipitation pulses of different lengths modulating distinct dynamic processes in the P. ferox woodlands. Interannual variations in precipitation influence year-to-year patterns of P. ferox radial growth, whereas multiannual oscillations in rainfall influence episodic events of tree establishment. The long-term interval considered in this study enabled us to disentangle the roles of natural versus human controls on P. ferox dynamics in the region.