RESUMEN
Severe dermatitis and branchitis are described in a wild population of empire gudgeon Hypseleotris compressa, an Australian eleotrid, exposed naturally to runoff from acid sulfate soils (ASS) in a drained estuarine embayment in eastern Australia. After at least 2 d exposure to pH < 4, and up to 7 d exposure to pH < 6, approximately 50% of the fish sampled had moderate to severe diffuse epidermal hyperplasia, usually at scale margins, and scattered areas of moderate to severe, focal to locally extensive, subacute, necrotising dermatitis. Saprolegnia spp. had invaded epidermis in some inflamed areas. In gills, there was moderate to severe hyperplasia and necrosis of secondary lamellar epithelium, with fusion of adjacent secondary lamellae. Inorganic monomeric aluminium and calcium concentrations in water at the site during the event were 27.7 and 16.6 mg l(-1), respectively. Large numbers of empire gudgeons at the study site had died after at least 8 d exposure to pH < 4, and up to 13 d exposure to pH < 6. These findings provide clear evidence that acidification of estuarine systems by runoff from ASS has deleterious effects on aquatic biota. Furthermore, study findings suggest a mechanism whereby lesions of epizootic ulcerative syndrome (EUS) may be initiated in estuarine fishes by a combination of sublethal exposure to ASS runoff and Aphanomyces invadans infection, a suggestion consistent with the geographic and temporal distribution of EUS outbreaks in Australian estuaries.
Asunto(s)
Dermatitis/veterinaria , Exposición a Riesgos Ambientales , Enfermedades de los Peces/inducido químicamente , Branquias/patología , Perciformes , Sulfatos/toxicidad , Contaminantes Químicos del Agua/toxicidad , Animales , Dermatitis/mortalidad , Dermatitis/patología , Monitoreo del Ambiente/estadística & datos numéricos , Femenino , Enfermedades de los Peces/mortalidad , Enfermedades de los Peces/patología , Técnicas Histológicas/veterinaria , Masculino , Nueva Gales del Sur , Lluvia , Piel/microbiología , Piel/patologíaRESUMEN
We report on a 3-month-old infant whose sirenomelia was diagnosed prenatally. The infant is neurologically normal and has "fusion" of the lower limbs with associated renal dysplasia, imperforate anus, pelvic and sacral "dysplasia," and genital abnormalities. In addition she has a preauricular skin tag and rib fusion. The infant's anomalies are compatible with life and surgical separation of the lower limbs is planned.
Asunto(s)
Ectromelia/patología , Anomalías Múltiples/patología , Anomalías del Sistema Digestivo , Ectromelia/diagnóstico por imagen , Ectromelia/embriología , Femenino , Humanos , Lactante , Pierna/anomalías , Embarazo , Ultrasonografía Prenatal , Anomalías UrogenitalesRESUMEN
A series of 28 patients is presented with the two conditions of omphalocoele and gastroschisis treated over a five-year period . Improved survival can be obtained by the use of staged procedures with a silastic prosthesis plus intravenous alimentation with later definitive operation. If peripheral veins are used, serious complications are almost totally avoided. This combined form of therapy is the treatment of choice in infants with massive defects in the abdominal wall.
Asunto(s)
Músculos Abdominales/anomalías , Músculos Abdominales/cirugía , Anomalías Múltiples/cirugía , Peso Corporal , Femenino , Gastrostomía , Hernia Umbilical/congénito , Hernia Umbilical/cirugía , Hernia Ventral/congénito , Hernia Ventral/cirugía , Humanos , Recién Nacido , Enfermedades del Recién Nacido/cirugía , Masculino , Nutrición Parenteral Total/efectos adversos , Nutrición Parenteral Total/métodos , Prótesis e Implantes , Elastómeros de Silicona , Mallas QuirúrgicasRESUMEN
Sixty-one children and infants who had significant gastroesophageal reflux and associated complications underwent 73 surgical procedures to control the reflux. In order to evaluate the procedure, several esophageal manograms were obtained from each patient, before, during, and after the operation. Delayed follow-up reports were also obtained from follow-up visits, letter and telephone contact, in order to assess how the patient had progressed. The results were evaluated by actuarial analytic methods. Ninety-four percent of the patients remained alive over the 7-year follow-up period. At the completion of the seventh year, 62% of these patients (actuarially calculated) remained event free. All events occurred within 18 months of surgery. One patient could not be traced at long-term follow-up, which was therefore 92% complete. The 7-year actuarial probability of failure of the fundoplication at this institution is 24% when performed using this technique in these patients. These findings support that manometric calibration of the antireflux procedure tends to give uniform results in pediatric patients, but, compared with other published series has not proved to be superior to procedures that employ only a rubber bougie in the esophagus as an obdurator to prevent a repair that will be too tight.
Asunto(s)
Fundus Gástrico/cirugía , Reflujo Gastroesofágico/cirugía , Análisis Actuarial , Adolescente , Niño , Preescolar , Esófago , Femenino , Estudios de Seguimiento , Humanos , Lactante , Masculino , ManometríaRESUMEN
Perforation is common in the young preschool child who has appendicitis, and can occur as the result of an ingested foreign body. A variety of objects have been incriminated. The present report describes a case in which the appendiceal wall was pierced by a stiff canine hair.
Asunto(s)
Apendicitis/patología , Apéndice , Perros , Migración de Cuerpo Extraño/patología , Cabello , Perforación Intestinal/patología , Absceso/patología , Absceso/cirugía , Animales , Apendicectomía , Apendicitis/cirugía , Apéndice/patología , Preescolar , Migración de Cuerpo Extraño/cirugía , Humanos , Perforación Intestinal/cirugía , MasculinoRESUMEN
This report describes a neonate with sirenomelia who was recently treated at British Columbia Children's Hospital. Prenatal diagnosis was made at 29 weeks' gestation. Survival was not anticipated. Cesarean-section at term showed a live 2,375-g infant with excellent Apgar scores. Anomalies noted were fused lower extremities, imperforate anus, colon atresia, bilateral fused pelvic kidneys with renal dysplasia, pelvic and sacral dysplasia, and genital abnormalities. Laparotomy and colostomy were performed. All other anomalies are compatible with life and she is neurologically normal. Eventual separation of the lower extremities is planned. This is the second reported case of survival in a patient born with sirenomelia.
Asunto(s)
Anomalías Múltiples/diagnóstico , Ectromelia/diagnóstico , Diagnóstico Prenatal , Adulto , Arterias/anomalías , Diagnóstico por Imagen , Femenino , Humanos , Recién Nacido , Pierna/irrigación sanguínea , Pelvis/irrigación sanguínea , EmbarazoRESUMEN
Twelve neonates with sacrococcygeal teratoma (SCT) have been treated at British Columbia Children's Hospital over the past 5 years. Clinically significant coagulopathy developed in four of these neonates and two died, one before surgical intervention could be undertaken. Disseminated intravascular coagulation (DIC) was found in one patient and thrombocytopenia in another on preoperative laboratory studies. Etiology of the coagulopathy is unclear, but appears to be multifactorial. Although several clinical reviews have noted mortalities due to exsanguinating hemorrhage, no study has focused solely on this issue. The diagnosis of SCT in the neonate at high risk for development of coagulopathy is usually made prenatally. Premature labor is often precipitated by associated polyhydramnios and large tumor size. Fetal distress, prematurity, and low birth weight are common. Presence of placentamegaly, hydrops fetalis, and congestive heart failure are ominous prognostic signs. Early identification of patients at increased risk for development of hemorrhagic complications may allow optimization of their management. Cesarean section should minimize trauma to the SCT during delivery. Expeditious resection of the lesion may improve survival.
Asunto(s)
Cóccix/anomalías , Trastornos Hemorrágicos/diagnóstico , Sacro/anomalías , Neoplasias de la Columna Vertebral/congénito , Teratoma/congénito , Pruebas de Coagulación Sanguínea , Cesárea , Cóccix/cirugía , Hemorragia/sangre , Hemorragia/mortalidad , Trastornos Hemorrágicos/sangre , Humanos , Recién Nacido , Complicaciones Posoperatorias/sangre , Complicaciones Posoperatorias/mortalidad , Diagnóstico Prenatal , Factores de Riesgo , Sacro/cirugía , Neoplasias de la Columna Vertebral/sangre , Neoplasias de la Columna Vertebral/cirugía , Teratoma/sangre , Teratoma/cirugíaRESUMEN
Despite proper technique, pull-through operations for Hirschsprung's disease sometimes fail to deliver normal or effective bowel evacuation. Ten patients, described herein, had had a pull-through procedures. The procedures had been performed by various pediatric surgeons. Five cases had been diagnosed in the newborn period and had undergone colostomies. The remainder had been diagnosed later (at 2 months to 2 years of age). They too had undergone colostomy initially, and all had an elective pull-through procedure. The techniques varied; two had Soave procedures, seven had Duhamel procedures, and one had a Kimura-Soave procedure (the only case of total colonic Hirschsprung's disease in the series). All the patients had manifested difficulty in passing stools after the pull-throughs. The problem was described as "severe constipation," "obstipation," or "fecal retention." Four patients had been treated with many laxatives, suppositories, enema routines, and diet regimens for years, with no success. All had been examined radiographically to detect megarectum or megacolon. All had additional biopsies to confirm the presence of ganglia in the pulled-through segments. At 21 months to 12 years of age, these patients underwent full posterior internal sphincterotomies. Nine of the 10 had a good or excellent outcome, with resolution of the megarectum or megacolon. Three patients still require small doses of senna compound, which are being decreased continuously. Therapy failed for a patient with Down's syndrome and a, Duhamel pull-through, and a stoma was required.
Asunto(s)
Canal Anal/cirugía , Colostomía/efectos adversos , Estreñimiento/etiología , Enterocolitis/etiología , Enfermedad de Hirschsprung/cirugía , Niño , Preescolar , Estreñimiento/cirugía , Enterocolitis/cirugía , Enfermedad de Hirschsprung/diagnóstico , Humanos , Lactante , ReoperaciónRESUMEN
Rhabdomyosarcoma is the most common childhood sarcoma, whereas, primary pararectal rhabdomyosarcoma is very rare. To date, four pediatric and eight adult cases have been reported. In children, the tumor presents as a perianal polypoid mass, often initially misdiagnosed. Formerly a very lethal sarcoma, rhabdomyosarcoma is now treated with combined surgery, radiation, and chemotherapy, with encouraging results.
Asunto(s)
Neoplasias del Ano/cirugía , Rabdomiosarcoma/cirugía , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias del Ano/patología , Femenino , Humanos , Lactante , Rabdomiosarcoma/tratamiento farmacológico , Rabdomiosarcoma/patologíaRESUMEN
Simultaneous occurrence of choriocarcinoma in mother and child is rare. Such a case is described in which a massive intrahepatic tumor in the infant led to its treatment and that of the mother who showed evidence of the same tumor. Both are alive and well 1 year after treatment, the longest recorded infant survival.
Asunto(s)
Coriocarcinoma/secundario , Neoplasias Hepáticas/cirugía , Neoplasias Pulmonares/secundario , Intercambio Materno-Fetal/fisiología , Neoplasias Uterinas/cirugía , Angiografía , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Quimioterapia Adyuvante , Coriocarcinoma/diagnóstico , Coriocarcinoma/tratamiento farmacológico , Coriocarcinoma/cirugía , Gonadotropina Coriónica/sangre , Gonadotropina Coriónica Humana de Subunidad beta , Terapia Combinada , Femenino , Estudios de Seguimiento , Humanos , Lactante , Neoplasias Hepáticas/diagnóstico , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Pulmonares/diagnóstico , Neoplasias Pulmonares/tratamiento farmacológico , Fragmentos de Péptidos/sangre , Embarazo , Tomografía Computarizada por Rayos X , Ultrasonografía , Neoplasias Uterinas/diagnóstico , Neoplasias Uterinas/tratamiento farmacológicoRESUMEN
Regular bowel washout enemas have been used as a method of management of fecal incontinence. The effective administration of a washout enema to a child with weak anal sphincters is often a problem. Using a new silastic balloon-tipped enema catheter (bowel management tube [BMT]) of our design, we prospectively studied its effectiveness in a group of children who suffered fecal incontinence. Thirty-one children were studied over a 1-year period. Their diagnoses included meningomyelocele (19), postoperative Hirschsprung's disease or imperforate anus (10), and other (2). Before and after starting the BMT enema system, clinical assessment and a diary, which graded the degree of fecal incontinence and satisfaction with the system, were completed. Five patients failed to benefit because of noncompliance (3) or balloon extrusion (2). Three more patients discontinued the use of the tube system. Twenty-three patients achieved successful results with this system as evidenced by a significant amelioration in their fecal incontinence and their unwillingness to give up the use of the BMT. We conclude that the use of a regular washout enemas with BMT can be an effective method for control of fecal incontinence in children.
Asunto(s)
Cateterismo/instrumentación , Enema/instrumentación , Incontinencia Fecal/rehabilitación , Enfermedades Neuromusculares/rehabilitación , Complicaciones Posoperatorias/rehabilitación , Adolescente , Ano Imperforado/cirugía , Niño , Preescolar , Diseño de Equipo , Femenino , Enfermedad de Hirschsprung/cirugía , Humanos , Masculino , Meningomielocele/rehabilitaciónRESUMEN
This report describes our experience in five cases, removing a massive soft tissue tumor by means of placing the patient on cardiopulmonary bypass, with profound hypothermia and circulatory arrest. This technique allowed consideration to be given to the resection of tumors previously adjudged "inoperable."
Asunto(s)
Puente Cardiopulmonar , Paro Cardíaco Inducido , Neoplasias Hepáticas/cirugía , Neoplasias de las Glándulas Salivales/cirugía , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Neoplasias Hepáticas/patología , Masculino , Neoplasias de las Glándulas Salivales/patologíaRESUMEN
The utilization of short stay surgical facilities is increasing and indications for day-care surgery for children are becoming more diverse. These trends were observed in a review of day-care surgery performed at British Columbia Children's Hospital during the years 1982 to 1986. During 1984 and 1985, 688 hernia repairs were undertaken, as were 76 anorectal procedures such as anal fistulotomy, drainage of abscesses, etc. In addition, 127 orchidopexies were performed, which indicated a 40% increase when compared with earlier years. Further procedures included the excision of 38 branchial cleft anomalies and 17 salivary gland lesions, as well as the performance of 95 tracheobronchial endoscopies including the removal of 25 foreign bodies. Head and neck and endoscopic procedures now represent 21% of all general surgery day care cases, and have increased by 50% since 1982. Thirty-six children (1.6%) initially brought in for day care surgery required actual admission to the hospital for such reasons as (1) the procedure being more complex than initially anticipated (15 patients); (2) hemorrhage (5 patients); or (3) postanesthetic concern (11 patients). Two thirds of the anesthetic complications were in infants less than 3 months of age. A special subgroup of high-risk infants were identified--the previous premature less than 52 weeks conceptual age. In our opinion, infants who are less than 3 months of age, especially if born prematurely, should be admitted to the hospital for surgery.
Asunto(s)
Procedimientos Quirúrgicos Ambulatorios/tendencias , Anestesia/efectos adversos , Colombia Británica , Niño , Humanos , Lactante , Pediatría , Complicaciones Posoperatorias , Servicio de Cirugía en HospitalRESUMEN
Neuroblastoma presenting as obstructive jaundice is very rare. The authors present two cases of neuroblastoma, one primary and one recurrent, manifesting as a malignant obstruction of the extrahepatic biliary system. Various methods of biliary decompression were considered in these children including transhepatic or retrograde biliary stenting and internal cholecystoenteric bypass. An attempt at percutaneous transhepatic stent placement failed in one case. In each patient, a simple insertion of a cholecystostomy tube proved effective. Immediately postoperatively, both patients had rapid resolution in symptoms and a decrease in bilirubin levels. Transient mild cholangitis in both children was successfully treated with antibiotics. Chemotherapy reduced the tumor size in each case, and the cholecystostomy tubes were removed within 3 weeks, after cholangiography showed patency of the distal common bile ducts. Temporary cholecystostomy tube drainage and systemic chemotherapy proved to be a safe, simple, and effective method for managing obstructive jaundice caused by neuroblastoma in these two cases.
Asunto(s)
Colestasis Extrahepática/etiología , Colestasis Extrahepática/terapia , Drenaje , Neuroblastoma/complicaciones , Neoplasias Pancreáticas/complicaciones , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Niño , Preescolar , Drenaje/métodos , Femenino , Humanos , Intubación , Masculino , Recurrencia Local de Neoplasia , Neuroblastoma/tratamiento farmacológico , Neoplasias Pancreáticas/tratamiento farmacológicoRESUMEN
Necrotizing fasciitis is a rare entity in the pediatric population. Five cases of this soft tissue infection were treated at the authors' institution between January and December 1993. Three of the children were profoundly neutropenic secondary to chemotherapy. All five were treated with aggressive surgical debridement, frequent dressing changes, broad-spectrum antibiotics, and nutritional support. In addition, the patients with neutropenia received a combination of granulocyte-colony stimulating factor and granulocyte transfusions. One child died of overwhelming sepsis and bone marrow graft failure. The others eventually made a complete recovery. Necrotizing fasciitis may be becoming a more common problem in children. Aggressive chemotherapeutic regimens and more frequent use of bone marrow transplantation could be a factor in this. Early diagnosis and aggressive surgical therapy is critical. However, mortality may be significant, especially in patients with neutropenia. Leukocyte response to the infection may be a prognostic marker. Pseudomonas and enteric gram-negative organisms are seen frequently in immunocompromised children with necrotizing fasciitis. Antimicrobial selection should supply adequate coverage of these organisms.
Asunto(s)
Fascitis Necrotizante/diagnóstico , Adolescente , Antibacterianos/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Infecciones Bacterianas , Vendajes , Trasplante de Médula Ósea/efectos adversos , Causas de Muerte , Niño , Preescolar , Terapia Combinada , Desbridamiento , Fascitis Necrotizante/etiología , Fascitis Necrotizante/patología , Fascitis Necrotizante/terapia , Femenino , Infecciones por Bacterias Gramnegativas/prevención & control , Factor Estimulante de Colonias de Granulocitos/uso terapéutico , Granulocitos/trasplante , Humanos , Huésped Inmunocomprometido , Lactante , Masculino , Neutropenia/inducido químicamente , Neutropenia/prevención & control , Nutrición Parenteral , Infecciones por Pseudomonas/prevención & control , Tasa de SupervivenciaRESUMEN
Traumatic splanchnic artery pseudo-aneurysms are uncommon; only two cases have been reported among the pediatric population. The authors describe their experience with four patients in whom splanchnic artery pseudoaneurysms developed after blunt abdominal trauma. Splenic artery pseudo-aneurysms were found in a 6-year-old boy and an 8-year-old girl after blunt splenic injuries. In both cases, spontaneous thrombosis of the pseudo-aneurysms occurred after a period of observation. Hepatic artery pseudoaneurysms were found in a 7-year-old boy and a 10-year-old girl after major liver lacerations. The boy had successful angiographic embolization of the lesion, but the girl required direct ligation of the pseudo-aneurysm after nearly exsanguinating from acute hemorrhage. All four children have recovered completely, with no long-term sequelae. Traumatic splanchnic artery pseudo-aneurysms are potentially life-threatening complications that can occur after blunt abdominal trauma. The investigation and management of these lesions must be individualized according to the clinical scenario.
Asunto(s)
Traumatismos Abdominales/complicaciones , Aneurisma Falso/etiología , Arteria Hepática/lesiones , Circulación Esplácnica , Arteria Esplénica/lesiones , Heridas no Penetrantes/complicaciones , Aneurisma Falso/diagnóstico , Aneurisma Falso/terapia , Niño , Embolización Terapéutica , Femenino , Humanos , MasculinoRESUMEN
Over the past 9 months, three cases of primary pulmonary rhabdomyosarcoma have been treated at British Columbia Children's Hospital. Two patients (aged 24 and 37 months) presented with spontaneous pneumothoraces and had cystic changes in the affected lung on chest radiograph. The third patient (aged 42 months) was evaluated for chronic cough, fever, and failure to thrive. Chest x-ray showed a large mass in the left lower lobe as well as mediastinal adenopathy. All three of these lesions originated within congenital lung cysts, one a peripheral bronchogenic cyst and the others cystic adenomatoid malformations. This report suggests that there is a significant risk for the development of rhabdomyosarcoma within malformed pulmonary tissue.
Asunto(s)
Transformación Celular Neoplásica/patología , Malformación Adenomatoide Quística Congénita del Pulmón/patología , Neoplasias Pulmonares/patología , Rabdomiosarcoma/patología , Preescolar , Malformación Adenomatoide Quística Congénita del Pulmón/cirugía , Femenino , Humanos , Pulmón/patología , Neoplasias Pulmonares/cirugía , Masculino , Neumonectomía , Rabdomiosarcoma/cirugíaRESUMEN
Comparative tests were carried out on serum samples using the Rose Bengal test (RBT), the complement fixation test (CFT), the antibovine globulin test (ABGT) by tube, plate and rapid variants, the mercaptoethanol test (MET) and the dithiothreitol test (DTT). Forty cows, from which Br. abortus had been recovered, gave strong reactions in all tests except for 2 cows in the SAT and 3 cows in the DTT Another group of 405 cows had not yielded Br. abortus on limited bacteriological examination. There was good correlation between the results of the CFT, RBT, tube ABGT, rapid ABGT and, to a lesser extent, the MET in cows with a CF titre greater than or equal to 16 or less than 4. In cows with CF titres of 8 the correlation was not as good while cows with a CF titre of 4 gave a wide range of reactions in these supplementary tests. A plate variant of the ABGT gave titres which were generally lower, by about 1 dilution, than those in the tube procedure. The results of the rapid ABGT correlated well with the results of the tube ABGT and the CFT in samples of high and low titre but not as well in samples of intermediate titre. The DTT gave titres which were usually lower than the corresponding MET titre. On the basis of the results obtained, tentative standards for the interpretation of the ABGT (tube) and MET were defined. It was concluded that these tests could be used to elucidate the status of a proportion of the cows which gave inconclusive results in the CFT.
Asunto(s)
Brucelosis Bovina/diagnóstico , Pruebas de Aglutinación , Animales , Anticuerpos Antibacterianos/análisis , Brucella abortus/inmunología , Bovinos , Pruebas de Fijación del Complemento , Ditiotreitol , Femenino , Mercaptoetanol , Rosa Bengala , Pruebas SerológicasRESUMEN
OBJECTIVE: To determine the effect of treating naturally acquired gastrointestinal nematode and paramphistome infections on milk production in dairy cattle. DESIGN: A field trial. ANIMALS: One thousand two hundred and thirty nine dairy cows. PROCEDURE: Cows were either not treated or treated with 4.5 mg/kg oxfendazole, 16.6 mg/kg oxyclozanide or 4.5 mg/kg oxfendazole and 16.6 mg/kg oxyclozanide in March, May and August. RESULTS: A significant increase in milk production, averaging 0.4 L (SE 0.2) per day, was seen when dairy cows infected with gastrointestinal nematodes and paramphistomes were treated with oxfendazole or oxfendazole and oxyclozanide in March, May and August. Cows treated with oxyclozanide alone at these times produced no more milk than untreated cows. Faecal egg counts confirmed that oxyclozanide treatment reduced paramphistome populations and oxfendazole treatment reduced nematode populations in cows over the 7-month monitoring period. CONCLUSION: When dairy cows infested with gastrointestinal nematodes and paramphistomes were treated with oxfendazole alone or oxfendazole and oxyclozanide in March, May and August milk production increased.
Asunto(s)
Antihelmínticos/uso terapéutico , Enfermedades de los Bovinos/tratamiento farmacológico , Parasitosis Intestinales/veterinaria , Leche/metabolismo , Infecciones por Nematodos/veterinaria , Paramphistomatidae/aislamiento & purificación , Infecciones por Trematodos/veterinaria , Animales , Antihelmínticos/efectos adversos , Bencimidazoles/efectos adversos , Bencimidazoles/uso terapéutico , Bovinos , Enfermedades de los Bovinos/epidemiología , Enfermedades de los Bovinos/metabolismo , Fasciola hepatica/aislamiento & purificación , Fasciola hepatica/fisiología , Heces/parasitología , Femenino , Helmintos/aislamiento & purificación , Helmintos/fisiología , Parasitosis Intestinales/tratamiento farmacológico , Parasitosis Intestinales/metabolismo , Lactancia , Nematodos/aislamiento & purificación , Nematodos/fisiología , Infecciones por Nematodos/tratamiento farmacológico , Infecciones por Nematodos/metabolismo , Nueva Gales del Sur/epidemiología , Oxiclozanida/efectos adversos , Oxiclozanida/uso terapéutico , Paramphistomatidae/fisiología , Recuento de Huevos de Parásitos/veterinaria , Prevalencia , Estaciones del Año , Infecciones por Trematodos/tratamiento farmacológico , Infecciones por Trematodos/metabolismoRESUMEN
Trends in the numbers of infective menatode larvae on pasture plots contaminated by cattle at different seasons of the year were defined in 3 different climatic regions. The main nematodes were Ostertagia ostertagi, Trichostrongylus spp, Haemonchus spp and Cooperia spp. On the North Coast of New South Wales with a sub-tropical climate, the numbers of infective larvae of all 4 nematodes rose rapidly to peak levels soon after each seasonal period of contamination began, then fell quickly within a few months. On the Central Coast of New South Wales, the trends were similar to those on the North Coast, except that the larvae persisted on the pasture for a much longer time. On the Northern Tablelands of New South Wales, where temperatures were much colder than on the coast, larval development was slower and major peaks of larval availability did not occur until early spring. These different seasonal trends in each region were considered to be related to the climatic differences between the regions. On pastures which were contaminated continuously, larval numbers reached maximum levels in mid-winter on the Central Coast and in early spring on the Northern Tablelands. It was concluded that the majority of these larvae were derived from the contamination of pastures in autumn and winter. Subsequently in summer, a rapid dying out of larvae was observed in all the regions, probably due to the effect of hotter weather. The studies suggest that a reduction in the contamination of pasture with nematode eggs in autumn and winter could result in pastures carrying fewer larvae and thus form the basis of effective worm control programs for cattle.