Dynamics of Fasciola hepatica infection in two species of snails in a rural locality of Mexico     

Cruz-Mendoza I  Figueroa JA  Correa D  Ramos-Martínez E  Lecumberri-López J  Quiroz-Romero H 《Veterinary parasitology》2004,121(1-2):87-93

The aim of the present study was to identify the species that are natural intermediate hosts of Fasciola hepatica in a Research Centre in Chapa de Mota, State of Mexico, Mexico, where temperate and humid conditions prevail. Also, the magnitude and dynamics of the natural infection in four biotopes were analysed. The study was performed between October 2000 and November 2001. The molluscs were collected, identified and studied for trematode infection. Soil humidity and temperature were determined monthly. A total of 4042 snails were collected 3372 (83%) were Fossaria humilis and 670 (17%) F. bulimoides. F. hepatica was present in 2537 (75.2%) and 515 (76.9%) of the two snail species, respectively. Temperature, soil humidity and microenvironment affected the dynamics of the host population and the parasite infestation, with a significant increase from August to November 2001. The highest prevalence was observed in the warmer and more humid biotopes.  相似文献   

The effects of oral magnesium hydroxide administration on rumen fluid in cattle     

Smith GW  Correa MT 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2004,18(1):109-112

This study was conducted to determine the effects of oral magnesium hydroxide administration on rumen fluid in cattle. Six lactating Holstein cows (4-7 years of age) with rumen fistulas were studied. Cattle were randomly assigned to receive boluses of magnesium hydroxide (162 g) or a powdered form (450 g dissolved in 3.5 L of water) PO daily for 3 days. Analysis of rumen fluid, blood gas tensions, and pH and measurement of serum magnesium concentrations were conducted daily. The study was discontinued after 72 hours, or sooner if rumen pH exceeded 8.0. After at least 3 weeks, the study was repeated with each cow receiving the other form of magnesium hydroxide (powder or bolus). Compared with baseline rumen pH (mean +/- SD: 6.22 +/- 0.28), magnesium hydroxide boluses caused a significant increase (P < .05) in rumen pH after 48 (7.27 +/- 0.11) and 72 (8.01 +/- 0.16) hours of administration, whereas the powdered form caused a significant increase (P < .05) in rumen pH after 24 (7.54 +/- 0.19) and 48 (8.43 +/- 0.22) hours of administration. Both the powdered and bolus forms of magnesium hydroxide decreased rumen protozoal numbers and increased methylene blue reduction times compared with baseline values. There was no change in blood pH, bicarbonate, or base excess values. Serum magnesium concentrations were significantly increased (P < .05) in cows that received the magnesium hydroxide powder. The results of this study indicate that magnesium hydroxide has a potent alkalinizing effect on rumen pH and significantly decreases rumen microbial activity.  相似文献   

Phenol poisoning in three dogs     

Gieger TL  Correa SS  Taboada J  Grooters AM  Johnson AJ 《Journal of the American Animal Hospital Association》2000,36(4):317-321

Three adult dogs were evaluated following oral administration of phenol by the owner. All three dogs experienced severe oral and gastric ulceration. Hematological abnormalities included neutropenia with the presence of toxic neutrophils, thrombocytopenia, and increased muscle enzymes. Endoscopic examination was performed, and biopsies yielded a diagnosis of gastric mucosal necrosis in two of the dogs. Following supportive care, the dogs recovered completely. Phenol is a caustic, highly poisonous derivative of coal tar. The dogs of this report were poisoned inadvertently by their owner who received misinformation concerning the use of this chemical via the Internet.  相似文献   

Metabolic and physiological characteristics of salt-tolerant strains of Bradyrhizobium spp.     

Faviana Barboza  Néstor S Correa  Susana B. Rosas 《Biology and Fertility of Soils》2000,32(5):368-373

 Biochemical and physiological characteristics of salt-tolerant (88 mM, 264 mM and 440 mM NaCl) strains of Bradyrhizobium were evaluated according to their capacity for using different carbon sources, growth rate, resistance to antibiotics, plasmid profile and exopolysaccharide production. Salt-tolerant strains significantly enhance their capacity to oxidize C sources (about 75–85 compounds) by increasing growth rate and exopolysaccharide production involved in adhesion, resulting in a greater adapting capacity to colonize unfavorable saline environments. However, salt stress could work as a curing agent and thus the gene stability would become critical for the biological nitrogen-fixation information present in plasmids, as is the case in Rhizobium. Received: 5 January 1998  相似文献   

Sun coral management effectiveness in a wildlife refuge from south-eastern Brazil     

Lucca A. C. Savio  Gustavo M. Dias  Kelen L. Leite  Silvia N. Godoi  Apoena C. Figueiroa  Geraldo F. O. Neto  Edineia C. Correa  Carlo L. B. Francini  Gustavo Shintate  Marcelo V. Kitahara 《水产资源保护:海洋与淡水生态系统》2021,31(10):2830-2841

1. The introduction of exotic species is one of the major causes for biodiversity loss in marine environments. Introduced species can change habitat complexity, impacting local communities and altering ecosystem functioning.
2. Since the 1980s, the scleractinian species Tubastraea coccinea and Tubastraea. tagusensis (commonly known as sun corals) have been spreading in the south-western Atlantic, posing a major threat to local biodiversity and marine ecosystems. Nowadays, these species are reported from more than 3,500 km along the Brazilian coast and on at least 21 oil and gas offshore platforms.
3. Considering the great environmental pressure resulting from sun coral invasion, this study verified the effectiveness of manual removal of Tubastraea spp. along a rocky shore in Alcatrazes Wildlife Refuge, one of the most pristine marine regions in Brazil.
4. Results indicate that removal is indeed effective as a control technique; however, as invaders have high regeneration capabilities and recruitment rates, successive management efforts are essential. In order for management to be effective against Tubastraea's year-round release of clonal larvae, results suggest invaded areas should receive at least two management actions per year.
5. Successive management efforts, in addition to the development of new techniques and prevention of new invasions should be priorities for mitigating sun coral impacts.

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Comparative drug systemic exposure and clinical efficacy against resistant nematodes in lambs treated with different albendazole formulations     

Suárez G  Alvarez L  Castells D  Correa O  Fagiolino P  Lanusse C 《Journal of veterinary pharmacology and therapeutics》2011,34(6):557-564

Suárez, G., Alvarez, L., Castells, D., Correa, O., Fagiolino, P., Lanusse, C. Comparative drug systemic exposure and clinical efficacy against resistant nematodes in lambs treated with different albendazole formulations. J. vet. Pharmacol. Therap. 34 , 557–564. A pharmaco‐parasitological assessment of four different albendazole (ABZ) formulations was carried out in lambs infected with multiple resistant gastrointestinal (GI) nematodes. The comparative drug systemic exposure profiles (ABZ sulphoxide plasma concentrations) and anthelmintic efficacies (clinical endpoint measured through the faecal nematode eggs reduction counts) were determined for a reference formulation (RF) and three different test (T1, T2, T3) generic ABZ preparations. Fifty (50) Corriedale lambs naturally infected with multiple resistant GI nematodes were allocated into five experimental groups (n = 10). Animals in each group received treatment with either the RF, one of the test ABZ formulations (5 mg/kg by the intraruminal route) or were kept as untreated control. Blood samples were collected over 48 h post‐treatment. ABZ parent drug was not recovered in the bloodstream. The ABZ sulphoxide (ABZSO) and sulphone (ABZSO₂) metabolites were measured in plasma by ultraviolet high‐performance liquid chromatography over 36–48 h post‐treatment. A faecal nematode egg count reduction test (FECRT) was performed at day 10th post‐treatment to lambs from all treated and untreated groups, which indicated the predominance of nematodes with high level of resistance to ABZ. Both ABZSO C_max and AUC_0–LOQ values obtained for the RF (pioneer product) were significantly higher (P < 0.05) than those obtained for the T1 and T3 preparations. Based on the currently available bioequivalence criteria, the test (generic) ABZ formulations under evaluation could not be considered equivalent to the RF regarding the rate (C_max) and extent (AUC_0–LOD) of drug absorption (indirectly estimated through the ABZSO metabolite). A large variation in nematode egg counts did not permit to obtain statistically significant differences among formulations. However, a favourable trend in the efficacy against the most resistant nematodes was observed for the formulations with the highest ABZSO systemic exposure.  相似文献   

Transmission dynamics of Fasciola hepatica in the Plateau Region of Mexico. Effect of weather and treatment of mammals under current farm management     

Cruz-Mendoza I  Quiroz-Romero H  Correa D  Gómez-Espinoza G 《Veterinary parasitology》2011,175(1-2):73-79

The aim of the present work was to study the dynamics of Fasciola hepatica natural infection in ovines, caprines, bovines and two mollusc species, Lymnaea (Fossaria) humilis and Lymnaea (F.) bulimoides, from 2004 to mid 2007 under normal farm management conditions, and the relation to climate changes. The study was performed in a research centre in the plateau of Mexico. Temperature and rainfall were registered every month, as well as the number and intensity of infection in livestock and molluscs, as determined by coprology and direct observation/cercariae release, respectively. The first two years mammals were treated with clorsulon/ivermectin because the animals were harbouring concomitant intestinal nematode infections and this was the available drug combination. During the second period treatment was with triclabendazole. The temperature ranged from around cero to 30 °C, except during September 2005 to January 2006, when a cold climate prevailed. The rainfall augmented every year in July-August, and slightly in April, 2006. Lymneid snails appeared during or immediately after the rainfall peaks of 2004 and 2006, while few L. humilis and no L. bulimoides were present during the same period of 2005, probably because it was cold. A total of 15564 cercariae were released from molluscs during the wet time of 2004, 76 during 2005 and 368 in 2006. Several peaks of infection in mammals were observed, most occurring up to 4 months after the snails had disappeared. As expected, the weather had strong impact on snails and then on livestock infection. Also, treatment given to livestock was related to reduced cercarieae release five months later. Therefore, the combination of treatment and inspection of snails in the biotopes where the livestock graze may facilitate control of fasciolosis under current farm management.  相似文献   

Past,present and future of wild ungulates in relation to changes in land use     

Pelayo Acevedo  Miguel Ángel Farfán  Ana Luz Márquez  Miguel Delibes-Mateos  Raimundo Real  Juan Mario Vargas 《Landscape Ecology》2011,26(1):19-31

In recent decades, Mediterranean landscapes have been experiencing more rapid changes in land use than usual, which have affected the ecology of the species inhabiting this biodiversity hotspot. Some studies have assessed the effect of such changes on biodiversity, but most of these were diachronic studies of population dynamics, or synchronic studies of species habitat selection, whereas few studies have simultaneously taken into account temporal changes in habitat composition and changes in species distribution. This study analysed the effects of land-use changes on the distribution of wild ungulates (Capreolus capreolus, Capra pyrenaica, Cervus elaphus and Sus scrofa). Using favourability function and Markov chain analysis combined with cellular automata, we addressed the following objectives: (i) to examine the environmental determinants of ungulate distribution in the past (1960s) and present (1990s), (ii) to model land use for 2040 to forecast future species distributions and (iii) to assess the biogeographical differences between the above-mentioned study periods (past–present and present–future). Species favourability was predicted to be more widely distributed in the present than in the past, but this increase varied across species. Areas predicted to be favourable in the present should remain stable in the future, but in addition there will be more new favourable areas not previously occupied by these species. The results are discussed from the perspective of the socio-economic relevance of wild ungulates in relation to some unfavourable areas of Mediterranean regions.  相似文献   

Ulcerative posthitis in bulls in Uruguay.     

F Riet Correa  A de Freitas  M V de Puignau  E Perdomo 《The Cornell veterinarian》1979,69(1):33-44

Ulcerative posthitis in bulls in Uruguay is described; 1096 bulls in 17 different establishments were examined. The incidence of bulls grazing on improved pasture was 32.9% in those under one year and 80.8% in animals of 18 to 36 months of age. Bulls grazing on natural pasture showed an incidence of 63.5% in adult animals irrespective of age. Histologic characteristics of the preputial lesions were acanthosis, parakeratosis and hyperkeratosis followed by invasion of leukocytes in the epithelium and ulceration. Corynebacterium renale was isolated from 59 of 204 prepuces. Based on the isolation of C. renale, histological lesions and the greater incidence in animals on high planes of nutrition, it is postulated that the lesion is due primarily to production of ammonia following the hydrolization of urea by the organism.  相似文献   

Importation of NZ bovine frozen embryos to Chile     

J E Correa  I Davis  S Ferguson 《The Veterinary record》1984,115(23):605-606

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