178 resultados para CARNIVORES


Relevância:

10.00% 10.00%

Publicador:

Resumo:

1. Hydatid cysts are found in more than 30 per cent of all cattle, sheep and goats in Kenya, but the disease is prevalent in man only in the semi-desert area of Turkana. Up to the time of the present investigation the life-cycle of the parasite in East Africa had not been studied, but it was suggested that wild carnivores, such as hyenas and jackals, might be the main hosts of the adult worms. 2. One hundred and forty-three carnivores, representing 23 species, have been examined. Echinococcus adults were found in 27 out of 43 domestic dogs (Canis familiaris), in three out of four hunting dogs (Lycaon pictus), in one out of nine jackals (Thos mesomelas), and in three out of 19 hyaenas (Crocuta crocuta). 3. A detailed morphological study was made of the Kenya material. After comparison with specimens from other parts of the world, it was concluded that the only species occurring in Kenya was E. granulosus, but it is possible that the minor morphological and biological differences are evidence of distinct strains. Further laboratory studies are necessary to compare the parasite from man and animals in different parts of Kenya with material from elsewhere. 4. A search was made for larval hydatids in 92 ungulates representing 18 species, and in a miscellaneous collection of nearly 2,000 rodents and primates representing a further 31 species. Only one animal was positive, a wildebeest (Gorgon taurinus). 5. The infections in the wild carnivores were all very light; only domestic dogs were heavily infected. It is concluded that the main cycle of transmission in Kenya is between dogs and domestic livestock. 6. Turkana tribesmen are the most heavily infected people in Kenya, either because the strain of parasite is more pathogenic to man in that area, or, more probably, because of the intimate contact between children and the large number of infected dogs. A particularly dangerous custom in the area is the use of dogs to clean the face and anal regions of babies when they vomit or have diarrhea. No satisfactory explanation can be given for the rarity of the disease in man in many of the other areas of Kenya where hydatids are very common in domestic animals. 7. The control of the disease will depend upon an active health-education campaign, together with the destruction of all unregistered dogs and improvement in meat hygiene.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Bovine tuberculosis (bovine TB), caused by Mycobacterium bovis, has reemerged in northern Michigan, USA, with detections in white-tailed deer (Odocoileus virginianus) in 1994 and in cattle in 1998. Since then, significant efforts have been directed toward reducing deer densities in the area in the hopes of reducing the bovine TB prevalence rate in deer and eliminating spillover of the disease into cattle. Despite the success of the efforts to reduce deer densities, additional cattle herds have become infected. Other mammals can be infected with M. bovis, and some carnivores and omnivores had been found to be infected with the disease in northern Michigan, USA. We conducted a multiyear surveillance effort to detect bovine TB in wild species of mammals in the Michigan, USA, outbreak area. From 2002 to 2004, tissue samples from 1,031 individual animals of 32 species were collected, processed, and cultured for M. bovis. Only 10 (1.0%) were culture-positive for M. bovis (five raccoons [Procyon lotor], four opossums [Didelphis virginiana], and one grey fox [Urocyon cinereoargenteus]). We also found two raccoons and four opossums to be positive for Mycobacterium avium. We collected 503 environmental samples from cattle farms recently identified as bovine TB positive; none yielded positive M. bovis culture results. Finally, we used infrared cameras to document wildlife use of four barns in the area. Many avian and mammalian species of wildlife were observed, with raccoons being the most commonly observed species. This surveillance study identified no new wildlife species that should be considered significant reservoirs of bovine TB in the outbreak area in northern Michigan, USA. However, the relatively high, apparent bovine TB prevalence rates in some carnivorous and omnivorous species, their relatively long life spans, and their frequent use of barns, suggests that removal of raccoons, opossums, foxes, and coyotes (Canis latrans) should be considered when a newly infected farm is depopulated of cattle.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Patterns of geographic variation of the canid Cerdocyon thous have historically been obscured by its remarkable intraspecific morphological variability. The observed distribution is highly associated with phytophysiognomy, a feature considered highly dynamic along geological time. In the present study, we tested whether vegetation distribution during the Holocene Glacial Maximum of South America (HGM) explains the patterns of morphological variation within Cerdocyon thous. The species was divided in groups according to paleohabitats that could support their presence during the HGM, and then tested for differences in skull morphometrics. The results obtained demonstrate that the climatic changes during the HGM influenced the population structure of this species, resulting in the establishment of geographical groups with different degrees of morphological cohesion. Higher morphological cohesion found in the Northern group might be explained by the marked discontinuity between its geographical range and the rest of the species`distribution. The Eastern and Southern morphological divergence is less striking and, although this could be related to past vegetation distribution, the disappearance of those barriers leads to a population structure that could be slowly breaking down. (C) 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 77-84.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Thirty-eight stations were sampled in Guanabara Bay, Rio de Janeiro, Brazil, to assess the spatio-temporal diversity and biomass of sublittoral polychaetes. Samples were collected during the dry (September 2000) and rainy season (May 2001) in shallow sublittoral sediments. The polychaete spatial composition showed a heterogeneous distribution throughout the bay. A negative gradient of diversity and biomass was observed towards the inner parts of the bay and sheltered areas. A wide azoic area was found inside the bay. Some high-biomass and low-diversity spots were found near a sewage-discharge point. In these areas, the polychaete biomass increased after the rainy season. A diversified polychaete community was identified around the bay mouth, with no dramatic changes of this pattern between the two sampling periods. Deposit-feeders were dominant in the entire study area. The relative importance of carnivores and omnivores increased towards the outer sector, at stations with coarse sediment fractions. Guanabara Bay can be divided into three main zones with respect to environmental conditions and polychaete diversity and biomass patterns: A) High polychaete diversity, hydrodynamically exposed areas composed of sandy, oxidized or moderately reduced sediments with normoxic conditions in the water column. B) Low diversity and high biomass of deposit and suspension-feeding polychaete species in the middle part of the bay near continental inflows, comprising stations sharing similar proportions of silt, clay and fine sands. C) Azoic area or an impoverished polychaete community in hydrodynamically low-energy areas of silt and clay with extremely reduced sediments, high total organic matter content and hypoxic conditions in the water column, located essentially from the mid-bay towards the north sector. High total organic matter content and hypoxic conditions combined with slow water renewal in the inner bay seemed to play a key role in the polychaete diversity and biomass. Sedimentation processes and organic load coming from untreated sewage into the bay may have negatively affected the survivorship of the fauna.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The Brazilian Atlantic forest has been reduced to a small fraction of its original area, with most remaining fragments being small and surrounded by anthropogenic matrices. This degree of disturbance, together with the increasing sprawl of cities towards the rural zone, greatly facilitates the entrance of domestic animals into these remnants. We used camera traps to compare the abundances of the domestic dog with a similarly sized native carnivore, the ocelot, in a 957-ha reserve of the Brazilian Atlantic forest in a landscape largely composed by pastures and agriculture. The dog was the most recorded species among all 17 mammal species "captured" by the cameras. Dog abundance (32-38 dogs) and density (0.812-1.813 dogs/km(2)) were significantly higher than that of the ocelot (n=2 ocelots; density=0.158-0.347 ocelots/km(2)). Although our result is restricted to a single study site, it is supported by an increasing number of recent studies, which have detected dogs inside other Atlantic forest reserves. Our study suggests, therefore, that this invasion might be more widespread than generally thought. The presence of the domestic dog is a threat to native fauna and constitutes an important edge effect of human presence at the rural zone.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Coexistence of sympatric species is mediated by resource partitioning. Pumas occur sympatrically with jaguars throughout most of the jaguar's range but few studies have investigated space partitioning between both species. Here, camera trapping and occupancy models accounting for imperfect detection were employed in a Bayesian framework to investigate space partitioning between the jaguar and puma in Emas National Park (ENP), central Brazil. Jaguars were estimated to occupy 54.1% and pumas 39.3% of the sample sites. Jaguar occupancy was negatively correlated with distance to water and positively correlated with the amount of dense habitat surrounding the camera trap. Puma occupancy only showed a weak negative correlation with distance to water and with jaguar presence. Both species were less often present at the same site than expected under independent distributions. Jaguars had a significantly higher detection probability at cameras on roads than at off-road locations. For pumas, detection was similar on and off-road. Results indicate that both differences in habitat use and active avoidance shape space partitioning between jaguars and pumas in ENP. Considering its size, the jaguar is likely the competitively dominant of the two species. Owing to its habitat preferences, suitable jaguar habitat outside the park is probably sparse. Consequently, the jaguar population is likely largely confined to the park, while the puma population is known to extend into ENP's surroundings. (C) 2011 Deutsche Gesellschaft fur Saugetierkunde. Published by Elsevier GmbH. All rights reserved.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The present study raised the hypothesis that the trophic status in a tropical coastal food web from southeastern Brazil can be measured by the relation between total mercury (THg) and nitrogen isotope (delta(15)N) in their components. The analysed species were grouped into six trophic positions: primary producer (phytoplankton), primary consumer (zooplankton), consumer 1 (omnivore shrimp), consumer 2 (pelagic carnivores represented by squid and fish species), consumer 3 (demersal carnivores represented by fish species) and consumer 4 (pelagic-demersal top carnivore represented by the fish Trichiurus lepturus). The values of THg, delta(15)N, and trophic level (TLv) increased significantly from primary producer toward top carnivore. Our data regarding trophic magnification (6.84) and biomagnification powers (0.25 for delta(15)N and 0.83 for TLv) indicated that Hg biomagnification throughout trophic positions is high in this tropical food web, which could be primarily related to the quality of the local water.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This study presents the electrocardiogram findings from 97 captive tufted capuchin monkeys (Cebus apella) at the Sao Paulo Zoo (Sao Paulo, Brazil) while under ketamine anesthesia. The results did not differ greatly from data of domestic carnivores or other studied primate species. The most common rhythm recorded was normal sinus rhythm, followed by normal sinus rhythm with wandering pacemaker. Electrical axis varied from 0 degrees to -150 degrees but was most commonly between +60 degrees and +90 degrees. QRS complexes were predominantly positive in leads DI, DII, DIII, and AVF. These findings allow for the recognition of abnormal rhythms in these primate species and can contribute to future investigations into the cardiovascular diseases routinely diagnosed in primates and humans.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

As ticks spend most of their time off-host, the environment is a major selective force of these parasites. In fact, human impact on landscapes has favored a minority of tick species which became well-known pests. However, this is an ongoing process and novel pests may arise. We herein report a surrogate life cycle of a neotropical tick species. Amblyomma ovate, and which may be related to an increased risk of human rickettsiosis. Under natural conditions, adults of this tick species feed on carnivores and exhibit non-nidicolous ambush behavior, whereas larvae and nymphs feed on small rodents and birds. In an anthropized spot within an Atlantic rainforest reserve of Brazil, an A. ovate population exhibited a nidicolous behavior with all 3 tick stages feeding on the dog. This dog's infestation was outstandingly high, and it displayed the highest anti-Rickettsia titers and harbored Rickettsia-infected ticks. (c) 2012 Elsevier GmbH. All rights reserved.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

O quati (Nasua nasua) é um animal que pertence à Família Procyonidae. Foram utilizados três animais ortotanasiados, de ambos os sexos, provenientes do Criatório Científico de Animais Silvestres, Centro Universitário Fundação de Ensino Octávio Bastos (Cecrimpas, Unifeob) autorizado pelo IBAMA (Proc.02027.003731/04-76). Para a análise macroscópica, as línguas foram retiradas, analisadas e foto-documentadas. Para análise microscópica, as línguas foram processadas rotineiramente pela técnica de microscopia eletrônica de varredura e inclusão em Paraplast; pela técnica de microscopia de luz os fragmentos foram cortados em micrótomo, com espessura média de 5mm e corados em HE e Picrosírius com fundo de hematoxilina. Os resultados macroscópicos e microscópicos mostram que a língua do quati apresenta papilas filiformes, fungiformes, valadas e cônicas sendo estas distribuídas nas regiões rostralis, medialis e caudalis. Histologicamente, a língua do quati é revestida por um epitélio pavimentoso estratificado queratinizado apresentando camada basal, espinhosa, granulosa e córnea com fibras de músculos estriados esqueléticos longitudinais e transversais e diversas glândulas. De acordo com os resultados pode-se concluir que a língua do quati possui características macroscópicas e microscópicas semelhantes aos canídeos, tendo como diferença o número de papilas valadas e o grau de queratinização.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Advances in the understanding of ecological factors determining predatorprey interactions have provided a strong theoretical background on diet preferences of predators. We examined patterns of jaguar predation on caiman in southern Pantanal, Brazil. We investigated factors affecting predation rates and vulnerability of caiman to predation by jaguars. We recorded 114 caiman mortality incidents. Predation accounted for 62.3% (n = 71) of all caiman found dead, while other causes of mortality (nonpredation) accounted for 37.7% (n = 43). We found that jaguars prey on a broad size range of caiman body and caiman predation was influenced by distance to forests. During dry seasons, 70% (n = 49) of deaths were due to predation, while 30% (n = 21) were due to nonpredation causes. However, we found no significant relationship between annual and monthly killings of caiman and rainfall totals by year and month (r = 0.130, r = -0.316). The annual flooding regime may be a more important factor influencing prey selection by jaguars. Although neotropical crocodilians are relatively well studied, their interactions with jaguars have been mostly ignored and should be prioritized in future studies.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

L’ampliamento dello spettro d’ospite è strettamente connesso al processo evolutivo a cui i virus sono assoggettati e rappresenta una notevole sfida alla loro capacità di adattarsi. L’attitudine a superare le barriere di specie è conseguente alla costante e relativamente rapida evoluzione che caratterizza i virus; allo stesso tempo, la forza selettiva esercitata dal nuovo ospite rappresenterà un ulteriore stimolo per le capacità adattative del virus. Ad oggi, i meccanismi genetici ed evolutivi responsabili del salto di specie virale, cioè la trasmissione di un virus da un ospite tradizionale ad uno precedentemente resistente all’infezione, sono parzialmente sconosciuti. Nel seguente lavoro verranno presentati gli studi effettuati sulle dinamiche evolutive caratterizzanti virus a RNA e a DNA in cui si sono osservate variazioni dello spettro d’ospite. Gli studi hanno riguardato i coronavirus, con particolare riferimento al ruolo svolto dai pipistrelli nell’evoluzione dei coronavirus SARS-correlati, e l’importanza del gatto nell’evoluzione dei parvovirus dei carnivori. Nella prima sezione saranno mostrate le correlazioni genetiche dei coronavirus identificati in Italia nei pipistrelli appartenenti alla specie Rhinolophus ferrumequinum con i ceppi europei e del resto del mondo, allo scopo di chiarire l’origine evolutiva dei coronavirus dei pipistrelli correlati al virus della SARS (Bat-SARS-like CoV) europei, gli eventi migratori che hanno caratterizzato la loro diffusione nel continente e le potenziali ripercussioni sulla salute pubblica. Nella seconda sezione saranno evidenziate le caratteristiche molecolari dei ceppi di parvovirus circolanti nella popolazione felina, valutandone la diversità di sequenza e la complessità genetica, allo scopo di ottenere importanti informazioni in merito all’evoluzione del virus e alle interazioni tra il parvovirus e l’ospite.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

ZusammenfassungrnrnrnDer Köderstreifentest, die Auswertung der Minicontainer und die Erfassung der Bodenlebewesen mit Hilfe der Bodenstechkerne ergeben zusammen eine gut standardisierte Methode zur Darstellung und Beurteilung der Mesofauna. Unter der Vorraussetzung gleicher abiotischer Faktoren ist es problemlos möglich, selbst unterschiedliche Standorte wie Agrarflächen, Weinberge und Waldböden vergleichend zu untersuchen.rnrnAuf den verschiedenen Versuchsflächen des Laubenheimer Weinberges gelingt es deutlich zu zeigen, wie wichtig eine naturnahe Begrünung für den Boden ist. Dies betrifft nicht nur die Entwicklung der Humusschicht und damit die Bodenlebewesen, sondern auch die Schaffung von Kapillaren und Poren, die durch schwere landwirtschaftliche Geräte im Rahmen der Bo-denverdichtung reduziert werden. Erosionserscheinungen kommen vollständig zum Stillstand. Das Ökosystem Boden sollte auch so gut wie keine Belastung durch Herbizide, Insektizide und Pestizide erfahren. Ähnliches gilt auch für agrarisch genutzte Flächen. rnrnDer Lennebergwald als Naherholungsregion von Mainz ist besonders schützenswert, da dieser durch intensiven Immissionseintrag aufgrund der Nähe zu den Autobahnen und durch die Eutrophierung über die Haustiere stark belastet wird. Die immer größere Ausdehnung des Siedlungsgebietes und die damit verbundene steigende Anzahl an Waldbesuchern, die durch Verlassen der vorgegebenen Wege den Boden zerstören, gefährden zusätzlich das Ökosystem.rnrnÜber Sinn und Zweck einer Flurbereinigung zu diskutieren ist hier nicht angebracht. Aus bo-denkundlicher Sicht ist sie nicht zu befürworten, da hiermit alle bodenbewahrenden Maßnah-men ignoriert werden. Wichtig ist es, bei den Landwirten Aufklärungsarbeit zu leisten, was bodenschonende und bodenweiterentwickelnde Bearbeitungsmethoden bedeuten. Mit Hilfe sachgemäßer Aufklärung und richtiger Umsetzung kann durch Begrünungsmaßnahmen der zum Teil sehr stark strapazierte Boden erhalten, gefördert und auf lange Sicht stabilisiert wer-den.rnrnAufgrund der festgestellten Tatsachen wurde ab 2008 auf eine flächige Dauerbegrünung um-gestellt, so dass es auch in den unbegrünten Rebzeilen zu einer Bodenverbesserung kommen kann. Mit großer Wahrscheinlichkeit dürfte diese schneller voranschreiten, da die Mesofauna von den benachbarten begrünten Rebzeilen einwandern kann. rnDie Mesofauna landwirtschaftlich genutzter Flächen und Waldgebiete kann, obwohl extrem unterschiedlich, miteinander verglichen werden.rnrnBrachflächen und Waldgebiete lassen sich aufgrund der unberührten Bodenstrukturen sogar gut miteinander vergleichen. Temperatur- und Niederschlagsverhältnisse müssen dabei über-einstimmen. Die Azidität der jeweiligen Böden gilt es zu berücksichtigen, da verschiedene Tiergruppen damit unterschiedlich umgehen. Collembolen bevorzugen neutrale Böden, wäh-rend Acari als Räuber mit den Lebewesen in sauren Böden besser zurechtkommen. Die Streu-auflage ist dabei von großer Bedeutung.rnrnIm Rahmen von Bearbeitungsmaßnahmen kommt es durch jeglichen Maschineneinsatz zu ei-ner mehr oder weniger starken Veränderung der Bodenstruktur und somit auch der darin le-benden Mesofauna. Bis sich diese erholt hat, steht meist schon die nächste Bodenbewirtschaf-tung an. Die Bodenverdichtung spielt auch eine Rolle. Bei herkömmlichem Ackerbau ist eine Fruchtfolge mit eingeschalteter Brache oder Gründüngung mit Klee oder Luzerne angebracht, um die Mesofauna nicht zu stark zu strapazieren. Organische Düngegaben leicht abbaubarer Streu sind deutlich zu bevorzugen gegenüber sehr zellulose- und ligninhaltigen Pflanzenresten. Die Einbringung von Stoppeln nach Aberntung von Getreidefeldern ist sinnvoll, solange dabei nicht zu tief in die Bodenstruktur eingegriffen wird (ZIMMER 1997).rnrnIm Rahmen der Sonderkultur Wein, bei der eine Bodenbearbeitung aus den aufgezeigten Gründen eigentlich nicht notwendig wäre, sind Dauerbegrünungsmaßnahmen generell von Nutzen: der Erosion wird vorgebeugt, die Bodenfeuchte konstant gehalten, der anfallende Mulch als Gründüngung genutzt. Dies sind alles entscheidende Faktoren, die die Meso- und Makrofauna fördern. Nur die Bodenverdichtung durch schweres Gerät, wie Schlepper und Vollernter, sind für den Boden nicht förderlich (HEISLER 1993, EHRENSBERGER 1993). Nie-derdruckreifen und Verringerung der Befahrung sind geeignete Gegenmaßnahmen. rnrnEntgegen landläufiger Winzermeinung, stellen die Pflanzen einer Begrünung eigentlich keine Konkurrenz für die Weinstöcke dar. Die Vorteile einer Begrünung sind nicht nur die Förde-rung der einheimischen Flora in ihrem standortgerechten Artenreichtum, sondern auch Ver-vielfältigung von Meso- und Makrofauna aufgrund der dadurch mehr anfallenden und ein-zuarbeitenden leicht abbaubaren Streu (GRIEBEL 1995).rn

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Biodiversity is rapidly declining, and this may negatively affect ecosystem processes, including economically important ecosystem services. Previous studies have shown that biodiversity has positive effects on organisms and processes across trophic levels. However, only a few studies have so far incorporated an explicit food-web perspective. In an eight-year biodiversity experiment, we studied an unprecedented range of above- and below-ground organisms and multitrophic interactions. A multitrophic data set originating from a single long-term experiment allows mechanistic insights that would not be gained from meta-analysis of different experiments. Here we show that plant diversity effects dampen with increasing trophic level and degree of omnivory. This was true both for abundance and species richness of organisms. Furthermore, we present comprehensive above-ground/below-ground biodiversity food webs. Both above ground and below ground, herbivores responded more strongly to changes in plant diversity than did carnivores or omnivores. Density and richness of carnivorous taxa was independent of vegetation structure. Below-ground responses to plant diversity were consistently weaker than above-ground responses. Responses to increasing plant diversity were generally positive, but were negative for biological invasion, pathogen infestation and hyperparasitism. Our results suggest that plant diversity has strong bottom-up effects on multitrophic interaction networks, with particularly strong effects on lower trophic levels. Effects on higher trophic levels are indirectly mediated through bottom-up trophic cascades.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Trichinellosis is a worldwide occurring zoonosis caused by the intracellular nematode Trichinella spp. One of the main infection sources in Europe is raw or undercooked meat from wild boar. Trichinella britovi is prevalent in wild carnivores in Switzerland, thus a possible inclusion of wild boar in this wildlife cycle cannot be excluded. In order to assess the prevalence of Trichinella infection in wild boar, we tested 1,458 animals with both parasitological and serological methods. In none of the animals Trichinella-larvae could be recovered by the artificial digestion method (prevalence of larvae: 0 %; 95 % CI 0.0 - 0.3). Antibodies in meat juice were detected in 57 animals using a standardized E/S-Ag-ELISA. However, in the confirmatory westernblot, only 3 animals remained seropositive (seroprevalence: 0.2 %; 95 % CI 0.07 %-0.60 %). The occurrence of wild boar positive for anti-Trichinella-antibodies indicates that meat inspection for Trichinella-larvae in this species is important to prevent human infections.