Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 45
Filter
1.
Animal ; 16 Suppl 3: 100537, 2022 Aug.
Article in English | MEDLINE | ID: mdl-35606270

ABSTRACT

Ruminants have evolved with the capability to recycle endogenous urea to the gastrointestinal tract (GIT). Ruminal ammonia derived from urea recycling makes a net contribution to digestible N flow if it is used to synthesise microbial protein. The dynamics of urea recycling and its quantitative importance to the N economy of ruminants are affected by dietary and physiological factors. In general, the transfer of endogenous urea to the GIT is related positively to blood urea concentration and rumen-fermentable energy supply and negatively to ruminal ammonia concentration. After consumption of a meal rich in rumen-degradable N, ruminal ammonia concentrations peak and can exceed the rate of carbohydrate fermentation, resulting in inefficient ammonia capture by microbes. These periods are characterised by greater ruminal ammonia efflux and reduced urea influx. A low ruminal ammonia concentration over time can stimulate recycling of endogenous urea-N to the rumen and its capture into microbial protein and reduce N excretion. Shifting protein digestion to the postruminal GIT can reduce ruminal ammonia concentration and increase plasma urea concentration, conditions that should promote greater reliance on urea recycling to meet N requirements of the rumen. Their ability to use non-protein N, of dietary or endogenous origin, to synthesise metabolisable protein and subsequently meat and milk contributes positively to the human-edible protein efficiency of ruminants. Dietary urea is rapidly degraded to ammonia in the rumen, and high rates of ammonia absorption across the rumen wall when a urea-rich meal is consumed can lead to hypophagic and toxic effects associated with urea feeding. Non-protein N absorbed in the postruminal GIT can contribute substantially to net urea and ammonia uptake into the portal vein, which reflects the potential for targeted urea release in postruminal sections of the GIT. In this review, we suggest that the regulation of urea recycling to the rumen is a critical step towards improved efficiency of ruminal N utilisation. We describe an approach by which postruminal urea supplementation, as an alternative to its ruminal application, may allow a slow and steady return of N to the rumen, avoid peaks in ammonia concentration associated with feeding, confer a greater and more efficient microbial synthesis, and improve fibre digestion compared with conventional urea supplementation.


Subject(s)
Rumen , Urea , Ammonia/metabolism , Animal Feed/analysis , Animals , Diet/veterinary , Dietary Proteins/metabolism , Digestion/physiology , Fermentation , Humans , Nitrogen/metabolism , Rumen/metabolism , Ruminants/metabolism , Urea/metabolism
2.
Microb Ecol ; 83(1): 202-215, 2022 Jan.
Article in English | MEDLINE | ID: mdl-33758979

ABSTRACT

Exposure to environmental stressors, an increasingly recurring event in natural communities due to anthropogenic-induced environmental change, profoundly impacts disease emergence and spread. One mechanism through which this occurs is through stress-induced immunosuppression increasing disease susceptibility, prevalence, intensity and reactivation in hosts. We experimentally evaluated how exposure to stressors affected both the physiology of avian hosts and the prevalence of the zoonotic bacteria Borrelia burgdorferi sensu lato (s.l.), in two model species-the blackbird Turdus merula and the robin Erithacus rubecula captured in the wild, using xenodiagnoses and analysis of skin biopsies and blood. Although exposure to stressors in captivity induced physiological stress in birds (increased the number of circulating heterophils), there was no evidence of increased infectivity to xenodiagnostic ticks. However, Borrelia detection in the blood for both experimental groups of blackbirds was higher by the end of the captivity period. The infectivity and efficiency of transmission were higher for blackbirds than robins. When comparing different methodologies to determine infection status, xenodiagnosis was a more sensitive method than skin biopsies and blood samples, which could be attributed to mild levels of infection in these avian hosts and/or dynamics and timing of Borrelia infection relapses and redistribution in tissues.


Subject(s)
Borrelia burgdorferi Group , Borrelia burgdorferi , Borrelia , Ixodes , Lyme Disease , Songbirds , Animals , Borrelia burgdorferi Group/physiology , Ixodes/microbiology , Lyme Disease/microbiology , Lyme Disease/veterinary , Songbirds/microbiology
3.
Animal ; 15(3): 100170, 2021 Mar.
Article in English | MEDLINE | ID: mdl-33485830

ABSTRACT

Male Holstein calves commonly receive minimal quantities of milk replacer (MR) to speed up weaning and reduce costs. Studies with Holstein female calves show that early life feed restriction affects energy metabolism later in life. Aiming to test this hypothesis, 120 Holstein bull calves (48.4 ± 2.2 kg of BW and 20 ± 3.2 d of age) housed in 24 pens were blocked and randomized to two treatments: A low calf MR allowance (LP) (two daily doses of 2 l each, 582 g/d of DM), or a high MR allowance (HP) (two daily meals of 4 l each, 1164 g/d of DM). Calves were weaned at day 49 of the study and slaughtered at 32.8 ± 0.5 weeks of age. Throughout the study, animals had ad libitum access to a common compound feed, straw, and water. Twenty-four animals were randomly selected for an intravenous glucose tolerance test (IVGTT). The IVGTT was performed at week 6 and 12 of the study and consisted of an intravenous glucose infusion and sequential blood sampling up to 90 min after glucose infusions. Calves were heavier for HP until week 12, after which the difference disappeared. By design, the MR intake was higher in the HP group resulting in a higher energy intake and a higher average daily gain in the preweaning phase. Blood glucose curves were not different at week 6, but at week 12, 5 min after the infusion, glucose was higher in HP calves. Insulin curves were not different at week 6. Nevertheless, in week 12, a higher insulin concentration was observed for HP 5, 10, 15, 20, 30, 35, and 45 min' postinfusion, indicating a higher requirement of insulin to control glycemia. Differences between HP and LP calves were also observed for the quantitative insulin sensitivity check index, maximum insulin concentration, and insulin delta at week 12. Blood glucose reached maximum concentration within 5-10 min of the IVGTT test, and the concentration was, on average, 8.58 and 10.80 mmol/l at weeks 6 and 12, respectively. Insulin reached maximum concentration within 10-15 min of the IVGTT, and concentrations were, on average, 33.32 and 32.61 µUI/ml at weeks 6 and 12, respectively. Doubling MR supply improved animal growth up to weaning, but these differences disappeared by the end of the feeding period. Despite similar responses to glucose infusions preweaning, higher milk supply seemed to decrease insulin sensitivity after weaning.


Subject(s)
Milk Substitutes , Milk , Animal Feed/analysis , Animals , Cattle , Diet , Energy Metabolism , Female , Male , Weaning
4.
Maturitas ; 141: 39-45, 2020 Nov.
Article in English | MEDLINE | ID: mdl-33036701

ABSTRACT

OBJECTIVES: To investigate the effect of omega-3 (ω-3) polyunsaturated fatty acid supplementation and a multidomain intervention (MI) (physical activity counselling, cognitive training and nutritional advice) among community-dwelling older adults on levels of intrinsic capacity (IC), a construct recently proposed by the World Health Organization. STUDY DESIGN: Secondary analysis from the factorial-design 3-year Multidomain Alzheimer Preventive Trial (MAPT) with 1445 subjects (64.2 % female, mean age 75.3 years, SD = 4.4) randomized to one group of MI plus ω-3 (800 mg docosahexaenoic acid and 225 mg eicosapentaenoic acid/day); MI plus placebo; ω-3 supplementation alone; or placebo alone. Data collection was held between 2008 and 2014. MAIN OUTCOME MEASURES: IC domains were examined with the Geriatric Depression Scale (psychological); Short Physical Performance Battery (mobility); Z-score combining four tests (cognitive function); and handgrip strength (vitality). All domains were combined into a composite IC Z-score. RESULTS: After 3 years, IC Z-score decreased among all groups when time was considered continuous (MI plus ω-3: -0.16, 95 %CI: -0.22 to -0.10; MI alone: -0.13, 95 %CI: -0.19 to -0.07; ω-3 alone: -0.19, 95 %CI: -0.25 to -0.10; placebo: -0.20, 95 %CI: -0.26 to -0.14; all p < 0.0001). There were no significant differences between groups. In a sensitivity analysis with categorical time, significant within-group declines were first identified at 24 months for all groups. CONCLUSIONS: This trial designed to improve cognitive function was unable to find effects of the intervention on the composite IC Z-score. Further investigations are needed, especially trials providing stronger interventions (such as exercise training and a controlled diet) and also embracing the sensorial domain of IC.


Subject(s)
Alzheimer Disease/prevention & control , Cognition/drug effects , Fatty Acids, Omega-3/therapeutic use , Aged , Aged, 80 and over , Dietary Supplements , Docosahexaenoic Acids , Eicosapentaenoic Acid/analogs & derivatives , Exercise , Fatty Acids, Omega-3/pharmacology , Female , Geriatric Assessment , Hand Strength , Healthy Lifestyle , Humans , Independent Living , Life Style , Longitudinal Studies , Male , Range of Motion, Articular/drug effects
5.
J Prev Alzheimers Dis ; 7(2): 70-74, 2020.
Article in English | MEDLINE | ID: mdl-32236394

ABSTRACT

BACKGROUNDS: The World Health Organization has published the Integrated Care for Older People, ICOPE handbook Guidance on person-centred assessment and pathways in primary care. This is an integrated individual care tool focused on the individual and healthy ageing. The ICOPE tool proposes step by step, a screening, a fine assessment, the development of a personalized care plan, its implementation and follow up and finally the consideration of the caregivers and community. The new Geroscience field is focusing on preventing age-related diseases, and should now investigate with the ICOPE tool the optimal maintenance of intrinsic capacity (IC) through mobility, cognition, psychology, vitality, hearing and vision. This article aims to present this new tool and to presents its innovative implementation at the Toulouse University Hospital through the INSPIRE study. We believe that the ICOPE integrated care program will also be a pragmatic way to maintain cognitive functions and detect early Alzheimer. OBJECTIVES: The main objective of the INSPIRE study is to build a Bio-resource Research Platform for Healthy Ageing gathering biological, clinical and digital resources in order to identify markers of ageing, age-related diseases and IC evolution. The study will be also testing the implementation and follow up of the ICOPE tool. METHODS: The Inspire Platform will gather clinical data and bio-specimens from 1000 subjects in the Occitania Region, of different ages (from 30 years and over) over 10 years. Data will be collected annually. Using the ICOPE tool IC domains will be monitored every 4 months. Once IC decline is identified, participants will have a thorough clinical assessment and blood sampling to investigate the response of markers of ageing at the time of decline. The French ethic committee approved the study. RESULTS: The Inspire platform aims to develop an integrative approach to promote novel new technologies for the assessment and monitoring of functional capacities.


Subject(s)
Aging/physiology , Delivery of Health Care, Integrated/organization & administration , Patient-Centered Care/organization & administration , Primary Health Care/organization & administration , Cohort Studies , Geriatrics/standards , Global Health , Humans , World Health Organization
6.
J Frailty Aging ; 9(1): 4-8, 2020.
Article in English | MEDLINE | ID: mdl-32150207

ABSTRACT

Biomarkers of frailty and sarcopenia are essential to advance the understanding of these conditions of aging and develop new diagnostic tools and effective treatments. The International Conference on Frailty and Sarcopenia Research (ICFSR) Task Force - a group of academic and industry scientists from around the world -- met in February 2019 to discuss the current state of biomarker development for frailty and sarcopenia. The D3Cr dilution method, which assesses creatinine excretion as a biochemical measure of muscle mass, was suggested as a more accurate measure of functional muscle mass than assessment by dual energy x-ray absorptiometry (DXA). Proposed biomarkers of frailty include markers of inflammation, the hypothalamic-pituitary-adrenal (HPA) axis response to stress, altered glucose insulin dynamics, endocrine dysregulation, aging, and others, acknowledging the complex multisystem etiology that contributes to frailty. Lack of clarity regarding a regulatory pathway for biomarker development has hindered progress; however, there are currently several international efforts to develop such biomarkers as tools to improve the treatment of individuals presenting these conditions.


Subject(s)
Frailty , Sarcopenia , Advisory Committees , Biomarkers , Congresses as Topic , Humans
7.
J Frailty Aging ; 9(1): 14-22, 2020.
Article in English | MEDLINE | ID: mdl-32150209

ABSTRACT

With aging populations around the world, frailty is becoming more prevalent increasing the need for health systems and social systems to deliver optimal evidence based care. However, in spite of the growing number of frailty publications, high-quality evidence for decision making is often lacking. Inadequate descriptions of the populations enrolled including frailty severity and frailty conceptualization, lack of use of validated frailty assessment tools, utilization of different frailty instruments between studies, and variation in reported outcomes impairs the ability to interpret, generalize and implement the research findings. The utilization of common data elements (CDEs) and core outcome measures (COMs) in clinical trials is increasingly being adopted to address such concerns. To catalyze the development and use of CDEs and COMs for future frailty studies, the Canadian Frailty Network (www.cfn-nce.ca; CFN), a not-for-profit pan-Canadian nationally-funded research network, convened an international group of experts to examine the issue and plan the path forward. The meeting was structured to allow for an examination of current frailty evidence, ability to learn from other COMs and CDEs initiatives, discussions about specific considerations for frailty COMs and CDEs and finally the identification of the necessary steps for a COMs and CDEs consensus initiative going forward. It was agreed at the onset of the meeting that a statement based on the meeting would be published and herein we report the statement.


Subject(s)
Biomedical Research/organization & administration , Frailty , Canada , Common Data Elements , Consensus , Humans , Outcome Assessment, Health Care
9.
J Nutr Health Aging ; 22(1): 117-130, 2018.
Article in English | MEDLINE | ID: mdl-29300431

ABSTRACT

OBJECTIVES: The objective of this study was to perform a systematic review to investigate the effects protein, essential amino acids (EAA), ß-hydroxy ß-methylbutyrate (HMB), creatine, dehydroepiandrosterone (DHEA) and fatty acid supplementation on muscle mass, muscle strength and physical performance of elderly subjects. METHODS: Using the electronic databases MEDLINE and EMBASE we identified RCTs published until February 2016 which assessed the effects of these nutrient supplementation on muscle strength, muscle mass or physical performance. Study selection and data extraction were performed by two independent reviewers. RESULTS: Search strategy allowed us to identify 23 RCTs. Among them, four used proteins as nutritional supplement, seven EAAs, six creatine, four DHEA and finally, two HMB. From our systematic review, it seems that the effects of these supplementations on muscle health are rather limited. Only consistent effects of EAA supplementation on physical performance (3 out of the 4 RCTs using EAA supplementation found significant effect of this supplementation on physical performance) and HMB supplementation on muscle mass (all the 2 identified RCTs using HMB supplementation found significant effect of this supplementation on muscle mass) have been found across studies. No consistent effects were found for the other types of dietary supplementation. Because of the important limitations in study design, inconsistency and lack of directness, the overall quality of the evidence was judged to be low or very low using the GRADE system. CONCLUSION: This systematic review showed a limited effect of nutritional supplementation on muscle mass, muscle power and physical function. Inconsistent positive effects were observed for some specific supplementations but the results only concerned one aspect of the muscle. Well designed and appropriately powered RCTs are needed to provide evidence for appropriate clinical recommendations.


Subject(s)
Amino Acids, Essential/metabolism , Creatine/metabolism , Dehydroepiandrosterone/metabolism , Dietary Proteins/metabolism , Exercise/physiology , Fatty Acids/metabolism , Muscle Strength/physiology , Muscle, Skeletal/physiology , Physical Functional Performance , Aged , Aged, 80 and over , Dietary Supplements , Female , Humans , Male , Middle Aged , Resistance Training
10.
Ticks Tick Borne Dis ; 7(1): 159-165, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26520052

ABSTRACT

The presence of Francisella species in 2134 ticks, 93 lagomorphs and 280 small mammals from the Iberian Peninsula was studied. Overall, 19 ticks and 6 lagomorphs were positive for Francisella tularensis subsp. holarctica, suggesting, as described for other regions, that lagomorphs may have an important role in the maintenance of F. tularensis in nature. Of the 6 positive lagomorphs, 4 were identified as the European rabbit, Oryctogalus cuniculus. Additionally, 353 ticks and 3 small mammals were PCR positive for Francisella-like endosymbionts (FLEs) and one small mammal was also positive for Francisella hispaniensis-like DNA sequences. Among FLE positive specimens, a variety of sequence types were detected: ticks were associated with 5 lpnA sequence types, with only one type identified per tick, in contrast to 2 lpnA sequence types detected in a single wood mouse (Apodemus sylvaticus). To our knowledge, this is the first report of FLEs in free-living small mammals as well as the first detection of F. hispaniensis-like sequences in a natural setting.


Subject(s)
Francisella/isolation & purification , Gram-Negative Bacterial Infections/veterinary , Ticks/microbiology , Animals , Animals, Wild , DNA, Bacterial/genetics , Francisella/genetics , Gram-Negative Bacterial Infections/epidemiology , Gram-Negative Bacterial Infections/microbiology , Livestock , Phylogeny , Polymorphism, Genetic , Portugal/epidemiology , Spain/epidemiology
11.
Ticks Tick Borne Dis ; 6(6): 743-50, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26159798

ABSTRACT

Wild birds may act as reservoirs for zoonotic pathogens and may be mechanical carriers of pathogen infected vector ticks through long distances during migration. The aim of this study was to assess tick infestation patterns in birds in Portugal and the prevalence of tick infection by Borrelia burgdorferi s.l. using PCR techniques. Seven tick species were collected from birds including Haemaphysalis punctata, Hyalomma spp., Ixodes acuminatus, Ixodes arboricola, Ixodes frontalis, Ixodes ricinus and Ixodes ventalloi. We found that I. frontalis and Hyalomma spp. were the most common ticks infesting birds of several species and that they were widespread in Portugal. Turdus merula was the bird species that presented the highest diversity of infesting ticks and had one of the highest infestation intensities. B. burgdorferi s.l. was detected in 7.3% (37/505) of Ixodidae ticks derived from birds. The most common genospecies was Borrelia turdi (6.9%), detected in ticks collected from Parus major, T. merula and Turdus philomelos, but Borrelia valaisiana (0.2%) and one Borrelia sp. (0.2%) similar to Borrelia bissettii (96% of similarity of the flaB gene in Blastn) were also detected. This study contributed to a better knowledge of the Ixodidae tick fauna parasitizing birds in Western Europe and to the assessment of the prevalence of B. burgdorferi s.l. associated with birds and their ticks.


Subject(s)
Bird Diseases/parasitology , Borrelia burgdorferi Group/isolation & purification , Ixodes/microbiology , Lyme Disease/veterinary , Tick Infestations/veterinary , Animals , Animals, Wild , Bird Diseases/epidemiology , Bird Diseases/microbiology , Birds , Lyme Disease/epidemiology , Lyme Disease/microbiology , Lyme Disease/parasitology , Molecular Sequence Data , Portugal/epidemiology , Tick Infestations/epidemiology , Tick Infestations/parasitology
12.
Comp Immunol Microbiol Infect Dis ; 37(2): 85-96, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24480622

ABSTRACT

In recent years, several emerging zoonotic vector-borne infections with potential impact on human health have been identified in Europe, including tularaemia, caused by Francisella tularensis. This remarkable pathogen, one of the most virulent microorganisms currently known, has been detected in increasingly new settings and in a wide range of wild species, including lagomorphs, rodents, carnivores, fish and invertebrate arthropods. Also, a renewed concern has arisen with regard to F. tularensis: its potential use by bioterrorists. Based on the information published concerning the latest outbreaks, the aim of this paper is to review the main features of the agent, its biology, immunology and epidemiology. Moreover, special focus will be given to zoonotic aspects of the disease, as tularaemia outbreaks in human populations have been frequently associated with disease in animals.


Subject(s)
Disease Outbreaks , Disease Reservoirs , Francisella tularensis/physiology , Tularemia/veterinary , Animals , Biological Warfare Agents , Bioterrorism , Europe/epidemiology , Francisella tularensis/pathogenicity , Humans , Immune System , Phylogeography , Tularemia/epidemiology , Tularemia/immunology , Tularemia/microbiology , Zoonoses
13.
J Nutr Health Aging ; 17(8): 688-93, 2013.
Article in English | MEDLINE | ID: mdl-24097023

ABSTRACT

UNLABELLED: Frailty tends to be considered as a major risk for adverse outcomes in older persons, but some important aspects remain matter of debate. OBJECTIVES: The purpose of this paper is to present expert's positions on the main aspects of the frailty syndrome in the older persons. PARTICIPANTS: Workshop organized by International Association of Gerontology and Geriatrics (IAGG), World Health Organization (WHO) and Société Française de Gériatrie et de Gérontologie (SFGG). RESULTS: Frailty is widely recognized as an important risk factor for adverse health outcomes in older persons. This can be of particular value in evaluating non-disabled older persons with chronic diseases but today no operational definition has been established. Nutritional status, mobility, activity, strength, endurance, cognition, and mood have been proposed as markers of frailty. Another approach calculates a multidimensional score ranging from "very fit" to "severely frail", but it is difficult to apply into the medical practice. Frailty appears to be secondary to multiple conditions using multiple pathways leading to a vulnerability to a stressor. Biological (inflammation, loss of hormones), clinical (sarcopenia, osteoporosis etc.), as well as social factors (isolation, financial situation) are involved in the vulnerability process. In clinical practice, detection of frailty is of major interest in oncology because of the high prevalence of cancer in older persons and the bad tolerance of the drug therapies. Presence of frailty should also be taken into account in the definition of the cardiovascular risks in the older population. The experts of the workshop have listed the points reached an agreement and those must to be a priority for improving understanding and use of frailty syndrome in practice. CONCLUSION: Frailty in older adults is a syndrome corresponding to a vulnerability to a stressor. Diagnostic tools have been developed but none can integrate at the same time the large spectrum of factors and the simplicity asked by the clinical practice. An agreement with an international common definition is necessary to develop screening and to reduce the morbidity in older persons.


Subject(s)
Adaptation, Physiological , Aging/physiology , Frail Elderly , Geriatric Assessment , Geriatrics , Stress, Physiological , Aged , Cardiovascular Diseases/etiology , Chronic Disease , Congresses as Topic , Greece , Humans , Neoplasms/etiology , Risk Factors , Societies, Medical , World Health Organization
14.
J Viral Hepat ; 20(6): 414-21, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23647958

ABSTRACT

Several new direct-acting antiviral (DAA) drugs are in development for chronic hepatitis C viral (HCV) infection, and NS3-NS4A serine protease and the NS5B RNA-dependent RNA polymerase have been the major targets. HCV variants displaying drug-resistant phenotypes have been observed both in vitro and during clinical trials. Our aim was to characterize amino acid changes at positions previously associated with resistance in protease (NS3) and polymerase (NS5B) regions from treatment-naïve HCV patients infected with genotypes 1a, 1b and 3a. All 1383 NS3 protease sequences (genotype 1a = 680, 1b = 498 and 3a = 205) and 806 NS5B polymerase sequences (genotypes 1a = 471, 1b = 329, 3a = 6) were collected from Los Alamos databank. Genotype 3a protease sequences showed the typical low-level resistance mutation V36L. NS3 sequences from other genotypes presented mutations on positions 36, 39, 41, 43, 54, 80, 109, 155 and 168 in a frequency lower than 2%, except for the mutation Q80R found in 35% of genotype 1a isolates. Polymerase sequences from genotype 3a patients showed five typical mutations: L419I, I424V, I482L, V499A and S556G. Two positions presented high polymorphism in the NS5B region from genotype 1a (V499A) and genotype 1b (C316N) subjects. Our results demonstrated a natural profile of genotype 3a that can be associated with the pre-existence of HCV variants resistant to first-generation protease inhibitors and to non-nucleoside polymerase inhibitors. Likewise, genotype 1b isolates and genotype 1a sequences exhibited pre-existing mutations associated with resistance to Palm II and Thumb I polymerase inhibitors, respectively.


Subject(s)
Drug Resistance, Viral , Hepacivirus/genetics , Protease Inhibitors/pharmacology , Viral Nonstructural Proteins/genetics , Amino Acid Substitution , Antiviral Agents/pharmacology , Base Sequence , Catalytic Domain , Databases, Genetic , Genotype , Hepacivirus/drug effects , Hepacivirus/enzymology , Hepatitis C, Chronic/drug therapy , Humans , Mutation Rate , Viral Nonstructural Proteins/antagonists & inhibitors
15.
Parasitol Res ; 112(5): 1903-12, 2013 May.
Article in English | MEDLINE | ID: mdl-23430359

ABSTRACT

Ticks consume resources from their hosts shaping their life-history traits and are vectors of many zoonotic pathogens. Several studies have focused on the health effects of blood-sucking ectoparasites on avian hosts, but there is limited information on the effects of ticks on adult and sub-adult birds, which may actively avoid ticks and are likely to present low infestation intensities. We evaluated the effects of the presence of feeding ticks and intensity of infestation on health variables of avian hosts. We also evaluated whether these variables were affected by tick infection by Borrelia burgdorferi sensu lato (s.l.) and by the presence of Borrelia infection on the birds' skin. Presence of parasite association among ticks, haemosporidea and Borrelia within the bird-host was also tested. We found that infestation by ticks significantly increased heterophyl/lymphocyte ratio in Turdus merula suggesting increased stress. This was especially evident at high infestation intensities when a significant decrease in body mass and body condition (body mass corrected for size) was also observed. Erithacus rubecula infested with more than 10 larvae tended to have lower haematocrit and blood haemoglobin. Plasma globulin concentration in T. merula tended to be affected by the presence of attached ticks and their infection with Borrelia, but this depended on the age of the bird. No association was detected among ticks, haemosporidea and Borrelia infection. We showed that ticks have detrimental effects on their avian hosts even under natural infestation conditions and that confirmed Borrelia reservoir hosts may also present symptoms of infection, though these may be subtle.


Subject(s)
Bird Diseases/physiopathology , Birds , Borrelia burgdorferi/pathogenicity , Lyme Disease/veterinary , Tick Infestations/veterinary , Ticks , Animals , Arachnid Vectors/parasitology , Bird Diseases/parasitology , Bird Diseases/transmission , Birds/microbiology , Birds/parasitology , Disease Reservoirs/veterinary , Female , Lyme Disease/physiopathology , Lyme Disease/transmission , Male , Tick Infestations/parasitology , Tick Infestations/pathology , Tick Infestations/transmission , Ticks/microbiology , Ticks/parasitology
16.
Environ Microbiol ; 15(2): 386-97, 2013 Feb.
Article in English | MEDLINE | ID: mdl-22882497

ABSTRACT

Birds are important in the ecology of Borrelia burgdorferi sensu lato (s.l.) because they are important hosts for vector tick immature stages and are known reservoirs for some Borrelia genospecies. The aim of our study was to assess the role of common passerine bird species as reservoirs for B. burgdorferi s.l. in Western Europe. We surveyed birds in enzootic areas in Portugal, where no information is available for birds as reservoirs for this aetiologic agent and where B. lusitaniae, for which few reservoirs have been identified, is the dominant genospecies. Twenty-three birds (2.9%), including Turdus merula, T. philomelos, Parus major and Fringilla coelebs harboured infected ticks, but only Turdus sp. harboured infected tick larvae. In one study area, although B. lusitaniae was dominant in questing Ixodes ricinus, no ticks feeding on birds were infected with this genospecies, and B. valaisiana was the dominant genospecies in I. ricinus larvae feeding on birds. In the other area ticks collected from birds were mainly I. frontalis which were infected with B. turdi. Two skin biopsies (4.2%) from two T. merula were positive, one for B. valaisiana and the other for B. turdi. This is the first report for B. turdi in Western Europe.


Subject(s)
Borrelia burgdorferi/physiology , Borrelia/physiology , Disease Reservoirs , Ectoparasitic Infestations/veterinary , Passeriformes/microbiology , Passeriformes/parasitology , Ticks/microbiology , Animals , Borrelia/classification , Borrelia/genetics , Borrelia burgdorferi/genetics , Ectoparasitic Infestations/microbiology , Host-Pathogen Interactions , Lyme Disease/transmission , Molecular Sequence Data , Phylogeny , Portugal , RNA, Ribosomal, 23S/genetics , RNA, Ribosomal, 5S/genetics
17.
Exp Appl Acarol ; 58(3): 327-39, 2012 Nov.
Article in English | MEDLINE | ID: mdl-22669280

ABSTRACT

The diversity and abundance of questing ticks and ticks parasitizing birds was assessed during 1 year in two recreational forests in western Portugal, a suburban forest and an enclosed game area. The aim of this study was to assess the distribution and seasonality of tick species and to understand the role of bird species as hosts for ticks. Ixodes ricinus was the most abundant questing tick collected in the enclosed game area, whereas in the suburban forest, only three ticks were collected by blanket dragging. Tick species parasitizing birds included I. ricinus, I. frontalis, I. arboricola, I. acuminatus, Haemaphysalis punctata, Hyalomma marginatum and H. lusitanicum. This is the first record of I. arboricola in Portugal. Tick prevalence and intensity of infestation differed between study areas and was higher in birds from the game area where a large population of deer and wild boar may support tick populations. Ground and shrub dwelling bird species such as Turdus merula, Erithacus rubecula and Sylvia melanocephala were the most heavily parasitized by ticks, but the importance of different bird species as hosts of larvae and nymphs of I. ricinus and I. frontalis differed. Therefore, different bird species may contribute differently for tick population maintenance.


Subject(s)
Birds/parasitology , Host-Parasite Interactions , Seasons , Tick Infestations/veterinary , Ticks/physiology , Animals , Geography , Population Density , Population Dynamics , Portugal , Species Specificity , Tick Infestations/epidemiology
18.
Appl Environ Microbiol ; 78(10): 3767-9, 2012 May.
Article in English | MEDLINE | ID: mdl-22407681

ABSTRACT

PCR screening of ticks and tissue samples collected from 151 Teira dugesii lizards seems to indicate a potential role of this lizard species in the maintenance and transmission cycle of some Ixodes ricinus tick-borne agents, such as Rickettsia monacensis, Rickettsia helvetica, and Borrelia lusitaniae, that are circulating on Madeira Island.


Subject(s)
Anaplasma phagocytophilum/isolation & purification , Borrelia/isolation & purification , Disease Reservoirs , Ixodes/microbiology , Lizards/microbiology , Rickettsia/isolation & purification , Tick-Borne Diseases/transmission , Anaplasma phagocytophilum/genetics , Animals , Bacteriological Techniques , Borrelia/genetics , Lizards/parasitology , Polymerase Chain Reaction , Rickettsia/genetics
19.
Clin Microbiol Infect ; 18(7): 696-701, 2012 Jul.
Article in English | MEDLINE | ID: mdl-21883668

ABSTRACT

Tick-borne relapsing fever (TBRF) is a spirochetal infection caused by the genus Borrelia. The disease is distributed in the Old and New World with many different species reported. In Europe, TBRF is caused by B. hispanica transmitted to man by Ornithodoros erraticus, a soft tick usually found in old premises to shelter pig herds. In Portugal, the first human case of TBRF was reported in 1942 but since the beginning of the 1960s, the disease has rarely been described and seems to either have disappeared or have been undiagnosed. Therefore, in 2009 a survey was undertaken to evaluate the presence of the tick in this type of premises and to evaluate its role as a reservoir of Borrelia. The work was carried out where the ticks were previously reported in the Alentejo and Algarve regions. Of 63 pigpens surveyed, O. erraticus was collected from 19% (n = 12) of these pigpens using CO(2) traps. To evaluate potential Borrelia hosts, both pigs (n = 25) and small rodents (n = 10) inhabiting these pigpens were surveyed for Borrelia presence, by whole blood PCR and/or tissue culture, respectively. All results for pigs and rodents were negative for the presence of B. hispanica. PCR assays targeting the 16S rRNA gene and intergenic spacer region of Borrelia were used. Sequence analysis of the positive samples confirmed the presence of B. hispanica in 2.2% (n = 5) of ticks from a pigpen in Alentejo. These results confirm natural, but albeit low, persistence of this agent in Portugal.


Subject(s)
Borrelia/isolation & purification , Ornithodoros/microbiology , Animals , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , DNA, Ribosomal/chemistry , DNA, Ribosomal/genetics , Disease Reservoirs , Molecular Sequence Data , Portugal , RNA, Ribosomal, 16S/genetics , Rodentia , Sequence Analysis, DNA , Swine
20.
Acta Med Port ; 22(3): 281-90, 2009.
Article in Portuguese | MEDLINE | ID: mdl-19686629

ABSTRACT

Tularemia is a zoonotic disease caused by Francisella tularensis. The etiological agent is transmitted to man by direct contact with infected animals, air, water or contaminated food, or through hematophagous vectors. In Portugal, in 1998, after an outbreak in Spain, the Direcção Geral de Saúde issued a warning, alerting the clinicians to the possibility of the disease spreading throughout the national territory. In this work, an epidemiological review of tularemia is made in order to contribute to the better knowledge of this disease.


Subject(s)
Tularemia , Humans , Tularemia/diagnosis , Tularemia/drug therapy , Tularemia/epidemiology , Tularemia/microbiology
SELECTION OF CITATIONS
SEARCH DETAIL
...