RESUMEN
The humoral and cell-mediated immune responses of pregnant cattle and their fetuses were examined at intervals after infection with Neospora caninum tachyzoites at mid-gestation (day 140). All cattle seroconverted and interferon gamma was detected in supernatants of peripheral blood mononuclear cells stimulated with specific antigen. At day 14 post-inoculation (pi), specific cell proliferation responses were detected in the lymph node draining the site of inoculation and in the uterine lymph node. The peak response was recorded in the majority of maternal lymph nodes by day 28 pi and cells from the maternal retropharyngeal lymph node, which in part drains the central nervous system, showed no specific activity to N. caninum until day 42 pi. This changing pattern of immune responsiveness may reflect parasite invasion and development within different host tissues. Fetal lymph node cells showed mitogen responsiveness from day 14 pi (day 154 of gestation) and also showed N. caninum-specific cell proliferation and interferon-gamma responses by day 28 pi (day 168 of gestation). At day 42 pi, specific cell-mediated immune responses were not apparent; however, N. caninum-specific fetal IgG and IgM antibodies were detected.
Asunto(s)
Enfermedades de los Bovinos/virología , Bovinos/parasitología , Coccidiosis , Transmisión Vertical de Enfermedad Infecciosa/veterinaria , Complicaciones Parasitarias del Embarazo/veterinaria , Animales , Anticuerpos Antiprotozoarios/sangre , Enfermedades de los Bovinos/inmunología , Células Cultivadas , Coccidiosis/inmunología , Coccidiosis/transmisión , Coccidiosis/veterinaria , Femenino , Feto/inmunología , Interacciones Huésped-Parásitos/inmunología , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Interferón gamma/biosíntesis , Leucocitos Mononucleares/inmunología , Ganglios Linfáticos/inmunología , Ganglios Linfáticos/parasitología , Neospora/fisiología , Embarazo , Linfocitos T/inmunología , Factores de TiempoRESUMEN
To investigate the pathogenesis of bovine neosporosis, 14 pregnant cattle were each inoculated subcutaneously with either 10(7) or 5 x 10(8) Neospora caninum (strain NC1) tachyzoites at 140 days' gestation. Serial necropsies were then carried out over an 8-week period. In the placenta, Neospora DNA and histopathological changes were observed in samples taken 14 days post-inoculation (dpi), with focal necrosis of maternal caruncular septa and fetal placental villi, serum leakage, and a maternal and fetal inflammatory response. At subsequent samplings, pathological changes in the placenta showed signs of resolution. No parasitaemia was detected in the dams in the two weeks following inoculation. In the fetus, Neospora DNA was detected at 14 dpi, and histopathological changes in the fetal central nervous system at 28 and 42 dpi consisted of small foci of necrosis and inflammation. Resolution of placental lesions during the experiment indicated that the disease was being controlled, and fetal infection, although established, did not appear to be progressing to a fatal outcome. The two doses of tachyzoites produced similar results, but the higher dose elicited earlier and more extensive lesions in the placenta and fetus. Control animals remained negative for all parameters recorded. It is concluded that in bovine neosporosis the placenta plays a central role in the pathogenesis and epidemiology of the infection, and that while primary tissue destruction by the parasite may endanger the fetus, the maternal and fetal inflammatory responses may also be damaging.
Asunto(s)
Enfermedades de los Bovinos/patología , Coccidiosis/patología , Neospora/patogenicidad , Complicaciones Infecciosas del Embarazo/patología , Infecciones Protozoarias en Animales , Animales , Temperatura Corporal , Bovinos , Enfermedades de los Bovinos/parasitología , Coccidiosis/genética , Coccidiosis/parasitología , ADN Protozoario/análisis , Femenino , Edad Gestacional , Neospora/genética , Placenta/parasitología , Placenta/patología , Embarazo , Complicaciones Infecciosas del Embarazo/parasitologíaRESUMEN
Neospora caninum is an important cause of fetal loss in cattle but has also infrequently been shown to cause disease in sheep and goats. Experimental infection of pregnant sheep with N. caninum causes clinical and pathological changes very similar to those of neosporosis in cattle. An experiment in sheep was undertaken to examine whether infection with N. caninum before pregnancy conferred immunity to subsequent challenge with the parasite during pregnancy. Primary inoculation of NC1 tachyzoites subcutaneously, either before or during pregnancy, caused a significant temperature response in ewes, while those given a secondary challenge at 90 days gestation (dg) did not show such a response. Primary infection of 12 ewes during pregnancy resulted in the loss of all fetuses while a further 12 ewes inoculated with NC1 tachyzoites before mating and subsequently challenged with the same dose at 90 dg produced nine live and seven dead lambs. There were no fetal deaths in ewes only infected with Neospora before mating although there was serological evidence of vertical transmission in four of their clinically normal offspring while Neospora DNA was detected in the cerebrospinal fluid of a fifth healthy lamb. Thus an experimental primary infection with N. caninum during pregnancy killed all the fetuses while inoculation before pregnancy did not cause any mortality but did provide a degree of protection against subsequent challenge with Neospora during pregnancy.
Asunto(s)
Coccidiosis/inmunología , Neospora , Complicaciones Infecciosas del Embarazo/inmunología , Animales , Animales Recién Nacidos , Anticuerpos Antiprotozoarios/sangre , Coccidiosis/sangre , Coccidiosis/parasitología , ADN Protozoario/análisis , Modelos Animales de Enfermedad , Femenino , Sangre Fetal , Inmunización/veterinaria , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Transmisión Vertical de Enfermedad Infecciosa , Neospora/inmunología , Neospora/aislamiento & purificación , Placenta/parasitología , Placenta/patología , Reacción en Cadena de la Polimerasa , Embarazo , Complicaciones Infecciosas del Embarazo/parasitología , Ovinos , Factores de TiempoRESUMEN
Three groups of eight pregnant sheep were inoculated with tachyzoites of the NCl isolate of Neospora caninum at 45 (group 1), 65 (group 2) or 90 (group 3) days' gestation. A further six animals (group 4) served as controls. Fourteen of the infected ewes developed a fever, which in two cases was biphasic. In six ewes in group 1, the fetuses died and were resorbed, and in the other two the fetuses were aborted. In group 2, one ewe resorbed her fetus, six aborted dead fetuses and one produced a live lamb. In group 3, six ewes aborted and two produced one live and one stillborn lamb each. Thus, the stage of gestation influenced the outcome of infection. All but one of the ewes "seroconverted", as shown by enzyme-linked immunosorbent assay, and 10 of 13 fetal sera examined by an indirect immunofluorescent antibody test were positive. The polymerase chain reaction was also used to detect DNA of N. caninum in aborted tissues. Immunohistochemical examination showed that the parasite had invaded the placentas of all cases examined, displaying an apparent predilection for fetal chorionic epithelium and fetal placental blood vessels, as well as inducing thrombosis in some maternal caruncular blood vessels. Organisms were associated with fetal vasculitis, focal degeneration and inflammation of the chorioallantois, and widespread, severe focal necrosis in the placentome. Characteristic lesions were seen in the fetal brains, in addition to focal leucomalacia, thought to be due to anoxia resulting from the placental damage. The six control sheep in group 4 remained clinically healthy and produced normal uninfected lambs.
Asunto(s)
Coccidiosis/veterinaria , Neospora/patogenicidad , Complicaciones Parasitarias del Embarazo/veterinaria , Enfermedades de las Ovejas/etiología , Ovinos/parasitología , Animales , Anticuerpos Antiprotozoarios/análisis , Encéfalo/inmunología , Encéfalo/parasitología , Encéfalo/patología , Coccidiosis/etiología , Coccidiosis/patología , Cartilla de ADN/química , ADN Protozoario/análisis , Ensayo de Inmunoadsorción Enzimática/veterinaria , Femenino , Feto/inmunología , Feto/parasitología , Feto/patología , Inmunohistoquímica , Neospora/genética , Neospora/inmunología , Placenta/parasitología , Placenta/patología , Reacción en Cadena de la Polimerasa/veterinaria , Embarazo , Complicaciones Parasitarias del Embarazo/etiología , Complicaciones Parasitarias del Embarazo/patología , Resultado del Embarazo/veterinaria , Enfermedades de las Ovejas/patología , VirulenciaRESUMEN
Sixteen sheep were inoculated subcutaneously over the left prefemoral lymph node with an abortifacient strain of Chlamydia psittaci. Groups of four animals were killed after 3, 6, 12 and 18 days. Four of eight sheep which received a control inoculum were killed on day 6 and four on day 18. The left and right prefemoral lymph nodes were removed and weighed and portions taken from each for examination by the polymerase chain reaction (PCR), by culture, and by histopathological and immunohistochemical methods. The left prefemoral lymph nodes enlarged after the injection of C. psittaci, with the group mean weight on day 6 being the greatest and that on day 18 being normal. Examination by "nested" PCR showed samples from these nodes to be positive, except for one animal killed on day 3 and one on day 12. Live organisms, however, were not cultured from any of the samples collected. C. psittaci antigen was detected immunohistochemically in three of four nodes on day 3, in each of four on day 6, and in two of four on both days 12 and 18. Nodes from the contralateral side remained normal, as did those from unchallenged control sheep, and no antigen or DNA was detected in them.
Asunto(s)
Antígenos Bacterianos/análisis , Chlamydophila psittaci/aislamiento & purificación , ADN Bacteriano/aislamiento & purificación , Lipopolisacáridos/análisis , Ganglios Linfáticos/microbiología , Psitacosis/veterinaria , Enfermedades de las Ovejas/microbiología , Animales , Anticuerpos Antibacterianos/inmunología , Anticuerpos Monoclonales/inmunología , Secuencia de Bases , Chlamydophila psittaci/inmunología , Femenino , Técnicas para Inmunoenzimas , Ganglios Linfáticos/patología , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Psitacosis/microbiología , Psitacosis/patología , Ovinos , Enfermedades de las Ovejas/patologíaRESUMEN
Analysis of the genomic DNAs of chlamydial isolates from sheep, cattle, and pigs was performed by Southern blot hybridization and by restriction endonuclease (RE) profiling of DNA amplified by PCR. The hybridization probes were derived from whole genomic DNA, the major outer membrane protein (MOMP) gene, the 16S rRNA gene, and an avian Chlamydia psittaci isolate plasmid. The PCR analysis used targets in the MOMP gene, the 16S rRNA gene, and the 60-kDa cysteine-rich protein gene. Together, the results showed that although there was considerable heterogeneity in the DNA sequence in the MOMP gene region, all the isolates had the same underlying total genomic RE profiles and yielded identical RE profiles for the rRNA and 60-kDa-protein gene regions. Most of the isolates were found to hybridize with the plasmid probe. Comparison of the MOMP sequence of one of the isolates (P787) with that of a known Chlamydia pecorum strain together with the results of the RE analyses allowed the conclusion that the isolates should all be classified within this new species.
Asunto(s)
Enfermedades de los Bovinos/microbiología , Infecciones por Chlamydia/veterinaria , Chlamydia/genética , Genoma Bacteriano , Enfermedades de las Ovejas/microbiología , Enfermedades de los Porcinos/microbiología , Secuencia de Aminoácidos , Animales , Artritis Infecciosa/microbiología , Artritis Infecciosa/veterinaria , Secuencia de Bases , Southern Blotting , Bovinos , Infecciones por Chlamydia/microbiología , ADN Bacteriano/genética , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Reacción en Cadena de la Polimerasa , Rumiantes/microbiología , Ovinos , PorcinosAsunto(s)
Vacunas Bacterianas/inmunología , Infecciones por Pasteurella/veterinaria , Neumonía/veterinaria , Enfermedades de las Ovejas/prevención & control , Vacunación/veterinaria , Animales , Femenino , Masculino , Infecciones por Pasteurella/inmunología , Infecciones por Pasteurella/prevención & control , Neumonía/inmunología , Neumonía/microbiología , Neumonía por Mycoplasma/inmunología , Neumonía por Mycoplasma/veterinaria , Ovinos , Enfermedades de las Ovejas/inmunología , Enfermedades de las Ovejas/microbiologíaRESUMEN
Single strains of serotypes A1, A2, A7 and A9 of Pasteurella haemolytica were separately used in combination with Mycoplasma ovipneumoniae to reproduce pneumonia. Macroscopically and microscopically the pneumonias associated with individual serotypes were similar and it is concluded that serotypes of P haemolytica isolated with low frequency in field disease may be equally virulent to common serotypes.
Asunto(s)
Infecciones por Pasteurella/microbiología , Pasteurella/clasificación , Neumonía/microbiología , Animales , Mycoplasma , Pasteurella/aislamiento & purificación , Serotipificación , OvinosRESUMEN
The inoculation of eight five- to seven-month-old sheep by the respiratory route with a culture of Mycoplasma arginini, administered simultaneously with or two days before a culture of Pasteurella haemolytica A2, did not lead to the pulmonary establishment of either organism. Minor lung changes found at slaughter seven days later were therefore considered not to have been induced by the inocula. Two other groups of seven sheep each were initially inoculated intratracheally with an ampicillin-treated lung lesion homogenate in which only M ovipneumoniae was detectable. After seven days one group was inoculated intranasally and intratracheally with mixed cultures of M arginini and P haemolytica A2, and one with P haemolytica A2 alone. In the M arginini-treated group pyrexia peaked earlier and one animal died, but no macroscopic or microscopic differences were apparent between the two groups at necropsy 10 to 11 days later; six sheep from each group had lung lesions indistinguishable from ovine atypical pneumonia. M arginini was isolated in high titre from the respiratory tract of two animals in the M arginini-treated group, including the sole fatality. However, an adventitious parainfluenza type 3 virus infection, identified in four animals from the M arginini-treated group and one from the other, may have been responsible for the inter-group clinical differences. It was concluded that the strain of M arginini used was capable neither of predisposing the lung to secondary invasion by P haemolytica A2, nor of exacerbating the pneumonia and effects elicited with M ovipneumoniae and P haemolytica.
Asunto(s)
Enfermedades Pulmonares/veterinaria , Mycoplasma/patogenicidad , Pasteurella/patogenicidad , Neumonía/veterinaria , Enfermedades de las Ovejas/etiología , Animales , Pulmón/patología , Enfermedades Pulmonares/etiología , Enfermedades Pulmonares/patología , Mycoplasma/aislamiento & purificación , Pasteurella/aislamiento & purificación , Neumonía/etiología , Neumonía/patología , Ovinos , Enfermedades de las Ovejas/patologíaAsunto(s)
Infecciones por Pasteurella/veterinaria , Neumonía por Mycoplasma/veterinaria , Neumonía/veterinaria , Enfermedades de las Ovejas/patología , Animales , Pulmón/patología , Mycoplasma/aislamiento & purificación , Pasteurella/aislamiento & purificación , Infecciones por Pasteurella/patología , Neumonía/patología , Neumonía por Mycoplasma/microbiología , Neumonía por Mycoplasma/patología , Ovinos , Enfermedades de las Ovejas/microbiologíaAsunto(s)
Mycoplasma/patogenicidad , Infecciones por Pasteurella/veterinaria , Pasteurella/patogenicidad , Neumonía por Mycoplasma/veterinaria , Enfermedades de las Ovejas/microbiología , Animales , Pulmón/patología , Infecciones por Pasteurella/patología , Neumonía por Mycoplasma/patología , Ovinos , Organismos Libres de Patógenos EspecíficosRESUMEN
The growth rate, feed consumption and carcase composition of nine untreated wether lambs (controls) were compared with those of lambs in which a chronic pneumonia had been experimentally induced. Six pneumonic lambs (group 1) were killed with the controls on day 109 and eight (group 2) lambs were killed when they had a similar mean liveweight to the controls (42 kg) on day 172. The mean liveweight gain of infected animals to day 108 was 59 per cent, the mean feed intake 69 per cent and the mean carcase weight of group 1 was 73.5 per cent that of the controls. Group 2 lambs required 25 per cent more feed and nine weeks longer than the controls to reach similar live and carcase weights. This depression of appetite and growth rate was most marked in the first 35 days after inoculation, but growth rates of infected lambs continued to be lower than those of the controls throughout the experiment. At slaughter, all infected lambs had consolidated lesions of pneumonia and a significant correlation was noted between the extent of lung lesions and total liveweight gain in individual lambs. Carcases of group 1 lambs had a proportionately low fat, high lean meat and bone content, indicative of immature development and consistent with a lowered feed intake. Carcases of group 2 lambs showed a similar trend but differences from the controls were not significant.
Asunto(s)
Neumonía/veterinaria , Enfermedades de las Ovejas/metabolismo , Animales , Peso Corporal , Ingestión de Alimentos , Infecciones por Pasteurella/metabolismo , Infecciones por Pasteurella/patología , Infecciones por Pasteurella/veterinaria , Neumonía/metabolismo , Neumonía/patología , Neumonía por Mycoplasma/metabolismo , Neumonía por Mycoplasma/patología , Neumonía por Mycoplasma/veterinaria , Ovinos , Enfermedades de las Ovejas/patologíaRESUMEN
Strains of Mycoplasma ovipneumoniae and Pasteurella haemolytica isolated from sheep affected with chronic pneumonia were inoculated by endobronchial route to conventionally-reared and SPF (Specific Pathogen-Free) lambs. Changes resembling those of the naturally-occurring disease were produced in most lambs given the organisms in combination and in some given M. ovipneumoniae alone. Similar but less extensive changes were seen in SPF lambs and fewer animals were affected. Different strains of M. ovipneumoniae did not affect the extent of changes produced in SPF lambs. M. ovipneumoniae became established in the lungs of both types of sheep; P. haemolytica did so less readily. It was concluded that chronic pneumonia may be reproduced in conventional animals by combined inoculation of M. ovipneumoniae and P. haemolytica. Age and status of immunity to mycoplasmas may account for the different responses of conventional and SPF lambs.