Assuntos
Actinas/metabolismo , Junções Célula-Matriz/metabolismo , Mecanotransdução Celular , Músculo Liso/metabolismo , Actinas/deficiência , Animais , Aorta/metabolismo , Colágeno/metabolismo , Matriz Extracelular/metabolismo , Imageamento Tridimensional , Camundongos Endogâmicos C57BL , Microscopia de Fluorescência , Relaxamento MuscularRESUMO
BACKGROUND: Many thoracic transplant recipients who receive organs from the same donor share facilities for 3 months, and are aware that they have received organs from the same donor. METHODS: A confidential questionnaire including open and closed questions assessed relationships between "twins" and the experience of having a twin. The Significant Others Scale assessed social support. Of 141 heart and 58 lung transplants, 25 pairs of transplant twins were identified. Questionnaires were sent to the 32 surviving twins. RESULTS: Twenty-six twins responded; 17 had received a heart and nine a lung. The 17 men and 9 women had a mean age of 51 years. Eighteen respondent's "twins" remained alive at the time of participation and eight had died. Sixty-six percent of the both- twin alive group and 43% of one-twin alive group felt they had a special bond with their twin, different from the other relationships that they have experienced. Fifty-six percent of the both-twin alive group and 43% of one-twin alive group felt having a twin enriched their transplant experience. Transplant twins rated social support last behind: the transplant support personnel; close family members; other transplant recipients; and good friends and general practitioners, both in levels of ideal and actual support. Transplant twins showed the largest discrepancy between levels of ideal and actual support than any other individual ranked. CONCLUSIONS: Being a transplant twin is a special experience that generally enriches the overall transplant experience but having a transplant twin, does not appear to enhance the amount of social support.
Assuntos
Transplante de Coração/métodos , Transplante de Pulmão/métodos , Doadores de Tecidos/psicologia , Coleta de Tecidos e Órgãos/métodos , Gêmeos/psicologia , Cadáver , Feminino , Humanos , Relações Interpessoais , Masculino , Pessoa de Meia-Idade , Apoio Social , Inquéritos e QuestionáriosRESUMO
AIM: To compare demographic, clinical and outcome data of Maori and Polynesian with New Zealand European heart transplant patients. METHODS: A retrospective analysis was made of data from the 104 patients who underwent heart transplantation at Green Lane Hospital over a period of twelve years, of whom 79 were European, 23 Maori/Polynesian, and two Asian. Clinical characteristics, blood group, HLA matching and outcomes of recipients were compared. RESULTS: There was no significant difference in age and gender between the two groups. Maori and Polynesian patients were heavier, had a greater body mass index and were more likely to have rheumatic heart disease than their European counterparts. Maori/Polynesian patients were predominantly blood group A, whilst European patients were mainly group O. The waiting time for a donor heart was similar in both groups. There was no significant difference in number of rejection episodes and survival. CONCLUSIONS: Green Lane Hospital has the largest international experience of heart transplantation in Maori and Polynesian patients. Although there are some differences in clinical profile, outcome in terms of rejection episodes and survival is similar in the two groups.
Assuntos
Etnicidade/estatística & dados numéricos , Transplante de Coração/mortalidade , Havaiano Nativo ou Outro Ilhéu do Pacífico/estatística & dados numéricos , Complicações Pós-Operatórias/mortalidade , Adolescente , Adulto , Criança , Comparação Transcultural , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Nova Zelândia/etnologia , Estudos Retrospectivos , Análise de Sobrevida , Resultado do Tratamento , Listas de EsperaRESUMO
AIMS: To determine the prevalence of cardiac allograft vasculopathy in heart transplant recipients at Green Lane Hospital and to examine potential risk factors for vasculopathy. METHODS: We retrospectively reviewed the coronary angiograms of all cardiac transplant recipients. Angiography was usually performed one, two and five years after operation. The diagnosis of allograft vasculopathy was made if there was any evidence of coronary artery disease. Patients' medical records were reviewed for potential risk factors. RESULTS: Ninety-one patients underwent cardiac transplantation between December 1987 and March 1998. One year survival was 87%. Angiographic evidence of coronary disease was present in 30 patients and in three patients coronary lesions were first identified at post mortem. Vasculopathy was present in 25%, 35% and 61% of patients at one two and five years following transplant. Donor-acquired lesions could not be excluded as few patients had immediate postoperative angiograms for comparison. Five late deaths have been due to vasculopathy. Recipient age, race, donor age and ischaemic time were similar for those with and without vasculopathy. Frequency or severity of acute rejection episodes, cytomegalovirus infection, lipid profiles, diabetes and hypertension were not significantly different in patients with vasculopathy. CONCLUSION: Cardiac allograft vasculopathy is a common finding after heart transplantation. No definite risk factors were identified in this patient group.
Assuntos
Doença das Coronárias/etiologia , Transplante de Coração , Complicações Pós-Operatórias , Adulto , Angiografia Coronária , Doença das Coronárias/diagnóstico por imagem , Doença das Coronárias/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Nova Zelândia , Estudos Retrospectivos , Fatores de Risco , Transplante Homólogo , Função Ventricular EsquerdaRESUMO
Effects of strategic anthelmintic treatment on pathophysiologic and immunomologic changes induced by infection with Ostertagia ostertagi and Cooperia oncophora were studied in 2 groups, of 12 calves each: an infected group, inoculated with 200,000 mixed O ostertagi and C oncophora third-stage larvae (L3) on day 1; and an infected-treated group, similarly inoculated, but treated with ivermectin at 9 and 33 days. All calves were also inoculated at 12 weeks with Brucella abortus vaccine, at 13 weeks with bovine rhinotracheitis vaccine (bovine herpesvirus 1), and at 14 weeks with a soluble O ostertagi L3 extract, then were allowed to graze on a contaminated pasture. Four calves from each group were slaughtered at 7, 11, and 19 weeks of the study. Calves of the infected group had significantly (P < 0.05) lower weight gain than did those in the infected-treated group (60.90 kg vs 75.86 kg). They also had high plasma pepsinogen and serum gastrin values, and low serum albumin concentration from 2 or 4 weeks. Calves in the infected-treated group had steady weight gain and no significant changes in albumin and gastrin values. They also had less severe abomasal lesions and higher carcass yield. Compared with calves of the infected-treated group, those of the infected group had significantly (P < 0.05) lower blood lymphocyte reactivity to phytohemagglutinin at 14 and 16 weeks, to concanavalin A at 10 weeks, to pokeweed mitogen at 14 weeks, and to soluble O ostertagi L3 extract at 2, 4, and 14 weeks. (ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Anti-Helmínticos/uso terapêutico , Vacina contra Brucelose/administração & dosagem , Brucella abortus/imunologia , Doenças dos Bovinos , Gastroenteropatias/veterinária , Herpesvirus Bovino 1/imunologia , Linfócitos/imunologia , Infecções por Nematoides/veterinária , Ostertagíase/veterinária , Vacinas Virais/administração & dosagem , Animais , Peso Corporal , Bovinos , Gastrinas/sangue , Gastroenteropatias/parasitologia , Gastroenteropatias/prevenção & controle , Ativação Linfocitária , Masculino , Nematoides/isolamento & purificação , Infecções por Nematoides/fisiopatologia , Infecções por Nematoides/prevenção & controle , Orquiectomia , Ostertagíase/fisiopatologia , Ostertagíase/prevenção & controle , Contagem de Ovos de Parasitas , Pepsinogênios/sangue , Fatores de Tempo , Aumento de PesoRESUMO
Immunomodulation by Ostertagia ostertagi and the effects of strategic anthelmintic treatments were studied in 3 groups of 6 calves each: an infected group, inoculated with 100,000 third-stage larvae (L3)/calf at 1 and 28 days; an infected-treated group, similarly inoculated, but treated with ivermectin 9 days after each inoculation; and a noninfected control group. Calves were grazed on 2 previously clean pastures, with the infected and infected-treated calves sharing 1 pasture. All calves were inoculated at 12 weeks with Brucella abortus and infectious bovine rhinotracheitis vaccines, and at 13 weeks with a soluble O ostertagi L3 extract (SLE). Infected and infected-treated calves had lower blood lymphocyte responses to phytohemagglutinin than did control calves at 2, 4, and 14 weeks, whereas the infected calves had higher responses at 6 and 8 weeks (P < 0.05). Responses to pokeweed mitogen followed a similar pattern, whereas those to SLE were low in all calves. Infected and infected-treated calves had increased values of IgG1 to excretory-secretory antigens of L4 larvae, but no changes in the values of IgG1 to SLE. They also had lower values of IgG and IgM to B abortus and antibodies to infectious bovine rhinotracheitis at 13 weeks. The infected-treated calves, however, had higher blood lymphocyte and monocyte counts and lower eosinophil count than did infected calves. They also had reduced abomasal mucosa thickness, abomasal wall weight, and abomasal lymph node weight than infected calves. It was concluded that O ostertagi causes nonspecific suppression of cellular and humoral immunity, hypersensitivity reactions coexisted with immunosuppression, and strategic anthelmintic treatments attenuated hypersensitivity reactions and initiated better immune responses.
Assuntos
Doenças dos Bovinos , Ivermectina/uso terapêutico , Ostertagíase/imunologia , Ostertagíase/veterinária , Abomaso/patologia , Animais , Anticorpos Antibacterianos/sangue , Brucella abortus/imunologia , Bovinos , Imunoglobulina G/sangue , Imunoglobulina G/classificação , Larva , Contagem de Leucócitos , Ativação Linfocitária , Masculino , Ostertagia , Ostertagíase/tratamento farmacológicoRESUMO
White-tailed deer (Odocoileus virginianus) collected in Maine (USA) from November 1988 to December 1989 were examined for Parelaphostrongylus tenuis. Relationships of deer age class, sex, collection year, and deer density to prevalence and intensity of P. tenuis infections were analyzed. Prevalence increased with deer age (P < 0.001) and interaction of deer age class and collection year (P < 0.001). Prevalence did not vary by year in deer > or = 1 yr old (85%, n = 519), but was higher in fawns in 1988 (66%, n = 87) than 1989 (23%, n = 73, P < 0.001). Based on such yearly variations, prevalence in fawns during late autumn could provide an index of annual transmission of P. tenuis. Intensity of P. tenuis averaged 2.5 worms per infected fawn (SD = 2.8, n = 72) versus 3.9 (SD = 3.1, n = 375) in deer > or = 1 yr old (P = 0.032). Neither prevalence (P > 0.50) nor intensity (P > 0.50) of infection was associated with deer density over a range of 1.4 to 5.8 deer per km2. Heads and fecal samples from the same individuals (n = 42) provided prevalence estimates of 73% and 44%, respectively. No differences in prevalence, intensity, or geographic distribution of P. tenuis in adult deer collected in Maine during fall were evident between the late 1980's (this study) and the late 1960's (Gilbert, 1973).(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Cervos/parasitologia , Metastrongyloidea/crescimento & desenvolvimento , Infecções por Strongylida/veterinária , Fatores Etários , Animais , Feminino , Maine/epidemiologia , Masculino , Metastrongyloidea/isolamento & purificação , Prevalência , Estações do Ano , Fatores Sexuais , Infecções por Strongylida/epidemiologia , Infecções por Strongylida/parasitologiaRESUMO
Most gastrointestinal nematode infections of cattle in the northeast USA are combinations of Ostertagia ostertagi and Cooperia oncophora. These infections are usually of little consequence in adult cattle because of immunity and consequent low levels of infection. Some work has been done on the effects of infection on milk production but the results are equivocal. Clinical ostertagiasis in calves can lead to mortality. Such outbreaks are often associated with situations where calves are pastured at an early age onto special calf pastures that are used consistently for this purpose. Subclinical ostertagiasis is more usual in this region where light infections become established in calves with no obvious clinical signs. Such infections exact a toll on productivity in the form of decreased weight gains, decreased carcass quality, reduced nitrogen balance and negative effects on post-absorptive protein metabolism. Subclinical infections can also cause transient suppression of cell-mediated immune responses in calves. Increases in fecal worm egg counts of cows have been shown to occur during the spring months and these may contribute to increased contamination of pastures. Ostertagia infective larvae overwinter successfully on pasture and can persist until midsummer. Typical egg production patterns in calves involve a prepatent period, after introduction to pasture in mid to late May, of approximately 3 weeks. Peak egg production occurs at about 6-8 weeks and is followed by a gradual decline in egg counts into the fall. Hypobiosis is very apparent in this region and is most pronounced in late fall (October-November).(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Doenças dos Bovinos/epidemiologia , Ostertagíase/veterinária , Ração Animal , Animais , Bovinos , Feminino , Parasitologia de Alimentos , Infecções por Nematoides/epidemiologia , Infecções por Nematoides/veterinária , New England/epidemiologia , Ostertagia/isolamento & purificação , Ostertagíase/epidemiologia , PoaceaeRESUMO
Four balance trials were conducted in 3 groups of 5 calves each at 0, 4, 8, and 14 weeks after initial inoculation with Ostertagia ostertagi. Group-1 calves were inoculated with 100,000 third-stage larvae (L3) of O ostertagi/wk for 14 weeks. Group-2 calves were inoculated with 10,000 L3/wk for 14 weeks, and group-3 calves were not inoculated. Effects of infection on apparent digestibilities of dry matter and nitrogen, and balances of nitrogen and water were evaluated. Neither clinically apparent (group 1) nor subclinical (group 2) O ostertagi infections had observable effects on the apparent digestibility of dry matter. Subclinical infection also had no significant effects on nitrogen digestibility or nitrogen and water balance. Clinically apparent infection, however, decreased the apparent digestibilities of nitrogen significantly (P < 0.05) at 4, 8, and 14 weeks after inoculation, and decreased nitrogen balance at 4 and 8 weeks after inoculation. Group-1 calves also had lower water intake, fecal-water excretion, and apparent water balance, but higher urinary water output at 4, 8, and 14 weeks after inoculation.
Assuntos
Doenças dos Bovinos/metabolismo , Doenças dos Bovinos/parasitologia , Nitrogênio/metabolismo , Ostertagíase/veterinária , Água/metabolismo , Animais , Bovinos , Digestão/fisiologia , Masculino , Ostertagíase/metabolismoRESUMO
Nutritional and physiologic effects of clinically apparent and subclinical Ostertagia ostertagi infections were studied in 3 groups of 5 calves each. Group-1 calves were inoculated with 100,000 Ostertagia ostertagi third-stage larvae (L3)/calf/wk for 14 weeks. Group-2 calves were inoculated with 10,000 L3/calf/wk for 14 weeks, and group-3 calves were no inoculated. Calves in group 1 had decreased dry matter intake and feed utilization from 4 weeks after initial inoculation. Group-2 calves had no changes in dry matter intake, but had decreased feed utilization at 12 and 14 weeks. Calves with clinically apparent infections (group 1) lost a mean weight of 11.8 kg, whereas calves with suclinical infections (group 2) lost a mean of 46.6 kg, and control calves lost a mean of 60.7 kg. Calves with O ostertagi infections (group 1 and 2) also had decreased carcass quality at slaughtering, which was reflected in decreased dressing weights and increased water-holding capacity of the rib-eye muscle. Calves in groups 1 and 2 also had lower carcass yield and rib-eye muscle weight, and group-1 calves had decreased protein content. Results of hematologic, pathologic, parasitologic, and clinical examinations mirrored nutritional changes.
Assuntos
Doenças dos Bovinos/fisiopatologia , Doenças dos Bovinos/parasitologia , Ostertagíase/veterinária , Fenômenos Fisiológicos da Nutrição Animal , Animais , Nitrogênio da Ureia Sanguínea , Composição Corporal , Bovinos , Doenças dos Bovinos/patologia , Creatinina/sangue , Ingestão de Alimentos , Crescimento , Masculino , Ostertagíase/patologia , Ostertagíase/fisiopatologia , Albumina Sérica/metabolismo , Redução de PesoRESUMO
Effects of Ostertagia ostertagi infection on secretion of insulin, pancreatic glucagon, cortisol, gastrin, and pepsinogen were studied in calves inoculated with 100,000 (group 1) or 10,000 (group 2) O ostertagi infective larvae weekly for 14 weeks. Plasma insulin concentrations in both inoculated groups were lower than those in a non-infected (group 3) control group. The differences between group 1 and group 3 were significant (P < 0.05) at 2 and 12 weeks after initial inoculation. Plasma pancreatic glucagon and cortisol concentrations of groups 1 and 2 did not differ significantly from those of the control group, although plasma pancreatic glucagon concentration was consistently lower in group-1 calves from 4 weeks to end of the study. Plasma pepsinogen and serum gastrin concentrations also increased significantly (P < 0.05) in both groups that received inoculations. We concluded that decreased plasma insulin concentrations are contributory to changes in postabsorptive protein metabolism, and that serum gastrin concentrations are more representative of the pathologic changes in the abomasum than are plasma pepsinogen concentrations.
Assuntos
Doenças dos Bovinos/sangue , Doenças dos Bovinos/parasitologia , Hormônios/sangue , Ostertagíase/veterinária , Animais , Bovinos , Gastrinas/sangue , Glucagon/sangue , Hormônios/metabolismo , Hidrocortisona/sangue , Insulina/sangue , Masculino , Ostertagíase/sangue , Pepsinogênios/sangueRESUMO
Pathophysiologic effects of Ostertagia ostertagi infection and their prevention by strategic anthelmintic treatments were studied in 3 groups each of 6 steer calves. Group-1 calves were noninfected controls. Group-2 calves were inoculated with 100,000 third-stage larvae on the 1st and 28th days of the experiment and grazed on pasture initially free of contamination. Group-3 calves were on a similar regimen as those in group 2, but were also treated with ivermectin 9 days after each larval inoculation. Group-2 calves had increased plasma pepsinogen and gastrin values and decreased weight gains, and total serum protein and albumin concentrations from the 2nd week of infection onward. They were anemic at 10 to 12 weeks and had lower carcass and meat quality at slaughter. Strategic anthelmintic treatments were effective in preventing these effects and calves in groups 1 and 3 had similar performances. On the basis of our findings, high pepsinogen values were related to worm burdens, whereas high gastrin concentrations were related to gastric lesions.
Assuntos
Doenças dos Bovinos/fisiopatologia , Ivermectina/uso terapêutico , Ostertagíase/veterinária , Abomaso/patologia , Animais , Proteínas Sanguíneas/análise , Nitrogênio da Ureia Sanguínea , Bovinos , Doenças dos Bovinos/tratamento farmacológico , Fezes/parasitologia , Gastrinas/sangue , Hematócrito/veterinária , Masculino , Carne/normas , Estado Nutricional , Ostertagia/isolamento & purificação , Ostertagíase/tratamento farmacológico , Ostertagíase/fisiopatologia , Contagem de Ovos de Parasitas/veterinária , Pepsinogênios/sangue , Distribuição Aleatória , Soroalbumina Bovina/análise , Aumento de PesoRESUMO
The possible development of type-1 hypersensitivity reactions in the abomasal mucosa caused by soluble L3 products of Ostertagia ostertagi was studied in 4-month-old calves sensitized by repeated exposure to L3 over a 50-day period followed by anthelmintic treatment. Four groups each of 4 calves were used. Group 1 served as nonsensitized controls and group 2 as sensitized controls, group 3 was challenge exposed at 2-week intervals beginning at week 10 with a soluble L3 product (OAG), and group 4 was challenge exposed at 2-week intervals with an oral dose of L3, followed by anthelmintic treatment 3 days later. All calves infected with L3 became sensitized, as indicated by a positive reaction to an intradermal skin test. However, a passive cutaneous anaphylaxis was only partly effective in indicating the presence of homocytotropic antibody in the infected calves. Sensitized calves had significantly (P less than 0.05) higher eosinophil counts and plasma pepsinogen values for the entire 14 weeks than uninfected controls. Globule leukocyte and mast cell counts from the abomasal mucosa were also significantly (P less than 0.05) higher. Studies for possible immunomodulation revealed that lymphocyte counts decreased between every 2-week challenge-exposure period for groups-3 and -4 calves. A transient depression of blood lymphocyte (BL) responses to phytohemagglutinin (PHA), a T-cell mitogen, was observed over the first 8 weeks in the infected calves. Increases in BL responses to OAG were also observed. Differences were not observed in BL responses to pokeweed mitogen, a T- and B-cell mitogen. Blood lymphocyte responses to PHA in group-3 calves were low following the initial challenge exposure with OAG.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Antígenos de Helmintos/imunologia , Doenças dos Bovinos/imunologia , Hipersensibilidade/veterinária , Ostertagíase/veterinária , Tricostrongiloidíase/veterinária , Abomaso/citologia , Animais , Bovinos , Doenças dos Bovinos/etiologia , Fezes/parasitologia , Fenbendazol/uso terapêutico , Hipersensibilidade/etiologia , Hipersensibilidade/parasitologia , Contagem de Leucócitos , Ativação Linfocitária , Masculino , Ostertagia/imunologia , Ostertagia/patogenicidade , Ostertagíase/etiologia , Ostertagíase/imunologia , Contagem de Ovos de Parasitas , Pepsinogênios/sangue , Distribuição Aleatória , Fatores de TempoRESUMO
Possible immunomodulation by low-level infection with Ostertagia ostertagi was studied in 4-month-old calves. Six groups of 4 calves each were subjected to the following regimens: group 1--nonparasitized controls; group 2--nonparasitized, but challenge exposed at day 64 with Brucella abortus strain 19 vaccine (BA) and at day 78 with IV administration of a soluble third-stage larval (L3) antigen preparation of O ostertagi (OAG); group 3--nonparasitized, but challenge exposed at day 78 with 75 x 10(3) L3 of O ostertagi; group 4--continuously parasitized by weekly dosing with 30 x 10(3) L3 of O ostertagi; group 5--continuously parasitized by weekly dosing with 30 x 10(3) L3 of O ostertagi, then challenge exposed on day 64 with BA and on day 78 with IV inoculation of OAG; and group 6--continuously parasitized by weekly dosing with 30 x 10(3) L3 of O ostertagi, then challenge exposed on day 78 with 75 x 10(3) L3 of O ostertagi. Over the initial 10 weeks of the study, nonparasitized calves, (groups 1, 2, and 3) had higher body weight, blood lymphocyte (BL) response to phytohemagglutinin (PHA), and significantly (P less than 0.05) higher feed consumption and lymphocyte numbers, whereas parasitized calves (groups 4, 5, and 6) had higher BL responses to pokeweed mitogen (PWM) and significantly (P less than 0.05) higher neutrophil and eosinophil numbers, plasma pepsinogen (PP) values, and BL response to OAG.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Antígenos de Helmintos/imunologia , Doenças dos Bovinos/imunologia , Imunização/veterinária , Ostertagia/imunologia , Ostertagíase/veterinária , Tricostrongiloidíase/veterinária , Abomaso/patologia , Animais , Anticorpos Anti-Helmínticos/análise , Proteínas Sanguíneas/análise , Peso Corporal , Bovinos , Contagem de Células/veterinária , Ingestão de Alimentos , Fezes/parasitologia , Contagem de Leucócitos/veterinária , Linfonodos/patologia , Ativação Linfocitária , Masculino , Ostertagíase/imunologia , Contagem de Ovos de Parasitas/veterinária , Pepsinogênios/sangueRESUMO
Mycobacterium paratuberculosis infection was detected in 2 goats in 1974 and in 5 goats in 1975; 5 of which were from a single herd. The magnitude of the subsequent epizootic in the goat herd was not recognized until 1977, when results of bacteriologic culture of fecal and tissue specimens, antibody determinations (agar-gel immuno-diffusion test), and histopathologic studies became available. By 1984, paratuberculosis had been diagnosed in 124 goats. Nearly all the goats were being used in antiserum production and had been given Freund complete adjuvant and human antigens. From 1974 to 1986, herd size varied from 100 to 300. The yearly incidence of paratuberculosis decreased from 13.2% (27 of 204 goats) in 1977 to 0% in 108 goats in 1985. The prevalence was higher in does. In goats that arrived on the farm in 1975 and before, 49 of 121 (40.5%) does developed paratuberculosis vs 41 of 120 (34.2%) wethers. In goats arriving on the farm in 1976 and after, 25 of 274 (8.5%) does and 9 of 216 (4.1%) wethers developed paratuberculosis. The average incubation period was approximately 4 years from arrival on the farm in every year except 1978, regardless of whether the goat was born on the farm or was purchased elsewhere.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Surtos de Doenças/veterinária , Cabras , Paratuberculose/prevenção & controle , Animais , Etambutol/uso terapêutico , Feminino , Imunodifusão , Isoniazida/uso terapêutico , Masculino , Paratuberculose/diagnóstico , Paratuberculose/epidemiologia , Paratuberculose/patologia , Rifampina/uso terapêutico , Fatores Sexuais , Redução de PesoRESUMO
Ostertagia ostertagi is widely distributed and is the most pathogenic of the parasitic nematodes affecting cattle in this region. Clinical ostertagiasis is seen mainly in calves and yearlings but outbreaks tend to be sporadic; the subclinical disease is of greater importance. Studies on the population dynamics of the free-living stages have shown that infective larvae can survive on pasture over the relatively severe winter conditions encountered in this region but that such pasture contamination declines during the succeeding grazing season and is lost by midsummer. In the host there is gradual acquisition of worms from pasture over the summer period, with relatively high burdens accumulating in the autumn. A dramatic shift in the proportion of adult to immature worms occurs during the autumn (October). By the time calves are housed, the proportion of larvae (mainly L4) is greater than 80%. This relative distribution of adults to larvae continues through the winter months until early spring when there appears to be a shift to a higher proportion of adults, presumably due to resumption of development of the L4. These persistent L4 stages are considered to be undergoing hypobiosis. Spring infections of calves appear to be mainly acquired from larvae that have successfully overwintered on pasture, and availability of these larvae is drastically reduced by midsummer. There appears to be negligible development of the eggs that result from the spring infections until late summer and early autumn. At this time because of favorable climatic conditions there is rapid larval development which can result in heavy infections in susceptible calves in the autumn.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Doenças dos Bovinos/epidemiologia , Ostertagíase/veterinária , Tricostrongiloidíase/veterinária , Animais , Bovinos , Clima , América do Norte , Ostertagíase/epidemiologia , Chuva , Estações do Ano , TemperaturaRESUMO
The possibility of a mucosal hypersensitivity reaction and its relationship to the pathogenesis of simulated natural infections with Ostertagia ostertagi were studied in calves. Four groups of 4 calves each were used. One group was used as noninfected control; a 2nd group was given increasing doses of infective larvae; a 3rd group was given increasing doses of larvae and these were removed by succeeding treatment with an anthelmintic; and a 4th group was given an initial dose of larvae which was then eliminated with an anthelmintic. All calves given larvae became sensitized, as shown by an intradermal skin test. The continuously infected calves had significantly (P less than 0.05) higher fecal egg counts, eosinophil counts, plasma pepsinogen values, and worm burdens and significantly (P less than 0.05) lower lymphocyte counts than did the other groups of calves. These animals also had the most extensive mucosal pathologic changes. The group given intermittent larval challenge exposures followed by an anthelmintic showed decreased lymphocyte values, but these were not significant. Plasma pepsinogen values of this group increased between every challenge exposure and treatment, a 3-day period. This indicated that a mucosal hypersensitivity reaction had occurred in these calves at these times, because they were shown to have been sensitized, and challenge-exposure infections were not present for sufficient time to have produced direct pathologic effects. It therefore seems that a part of the pathologic changes in O ostertagi infections may be the result of the continuous challenge exposure experienced by the animals through a constant intake of larvae from pasture and the intestinal reaction to this challenge exposure.
Assuntos
Doenças dos Bovinos/parasitologia , Ostertagíase/veterinária , Tricostrongiloidíase/veterinária , Animais , Bovinos , Doenças dos Bovinos/etiologia , Doenças dos Bovinos/imunologia , Fezes/parasitologia , Hipersensibilidade/veterinária , Ostertagíase/etiologia , Ostertagíase/imunologia , Contagem de Ovos de Parasitas/veterinária , Testes Cutâneos/veterináriaRESUMO
From autumn (April) to spring (November), groups of pregnant and dry Merino ewes grazed pasture contaminated with infective larvae of Haemonchus contortus, Ostertagia circumcincta and Trichostrongylus colubriformis. A periparturient rise in faecal egg counts occurred in the pregnant ewes, following the maturation in early spring of arrested fourth-stage larvae of H. contortus and failure of pregnant ewes to expel the resulting adult worms. Peak egg counts were seen in September, just before lambing. In dry ewes, egg counts were slightly elevated at the time of the rise in the pregnant ewes, but fell to very low levels as adult worms developing from previously arrested larvae were expelled. Lactating ewes acquired greater burdens of O. circumcincta and T. colubriformis than did dry ewes, but were equally refractory to new infections with H. contortus. It is therefore suggested that the impairment of immunity to helminth infection seen in reproductive ewes may be more specific than was previously envisaged.
Assuntos
Lactação , Complicações Infecciosas na Gravidez/veterinária , Doenças dos Ovinos/parasitologia , Tricostrongiloidíase/veterinária , Animais , Suscetibilidade a Doenças , Feminino , Hemoncose/parasitologia , Hemoncose/fisiopatologia , Hemoncose/veterinária , Haemonchus/crescimento & desenvolvimento , Trabalho de Parto , Ostertagia/crescimento & desenvolvimento , Ostertagíase/parasitologia , Ostertagíase/fisiopatologia , Ostertagíase/veterinária , Contagem de Ovos de Parasitas/veterinária , Gravidez , Complicações Infecciosas na Gravidez/parasitologia , Complicações Infecciosas na Gravidez/fisiopatologia , Ovinos , Doenças dos Ovinos/fisiopatologia , Tricostrongiloidíase/parasitologia , Tricostrongiloidíase/fisiopatologia , Tricostrongilose/parasitologia , Tricostrongilose/fisiopatologia , Tricostrongilose/veterinária , Trichostrongylus/crescimento & desenvolvimentoRESUMO
The population dynamics of concurrent infections of Syphacia obvelata and Aspiculuris tetraptera (Nematoda) in laboratory mice were investigated under conditions of constant re-exposure over periods of 56 and 115 days. The results indicate that A. tetraptera burdens equilibrate at a higher level than S. obvelata burdens and that both parasites become aggregated in the mouse population. Parasite burdens were higher following short-term (7 day) exposure of uninfected tracer mice to both parasites when compared with parasite burdens attained over long-term exposure, indicating probable development of immunity. A significant positive correlation was detected between numbers of immature S. obvelata and immature A. tetraptera for both experimental and tracer mice.