RESUMO
Trypanosoma vivax is a blood parasite of ruminants that was introduced into Latin America in cattle imported from Africa, possibly in the late 19th century. The parasite has now spread to ten of the 13 countries of the South American continent, often resulting in a severe wasting disease and death. Here, we review the current state of knowledge about this parasite and the problems faced by animal health agencies in controlling the disease.
Assuntos
Trypanosoma vivax , Tripanossomíase Bovina/epidemiologia , África/epidemiologia , Animais , Bovinos , América do Sul/epidemiologia , Tripanossomíase Africana/epidemiologia , Tripanossomíase Bovina/diagnóstico , Tripanossomíase Bovina/prevenção & controleRESUMO
Thirty-eight dual purpose calves in the 3 agricultural zones of the state of Yucatan, Mexico were monitored for antibodies to Babesia bovis and B. bigemina from close to birth up to 12 months of age. The results showed that infection with both parasites is widespread throughout the 3 zones. Many of the animals had produced antibody to both parasites by 6 months of age indicating high transmission rates resulting in enzootic stability for both parasites. Any changes to agricultural practices in the state that could affect disease stability through either reduction in numbers of tick vectors or the introduction of susceptible adults will have to be accompanied with measures such as vaccination to limit losses due to clinical babesiosis.
Assuntos
Criação de Animais Domésticos/métodos , Babesiose/epidemiologia , Doenças dos Bovinos/epidemiologia , Distribuição por Idade , Animais , Anticorpos Antiprotozoários/sangue , Babesia/imunologia , Babesia bovis/imunologia , Bovinos , México/epidemiologia , PrevalênciaRESUMO
OBJECTIVE: To determine the incidence of significant nocturnal hypoglycemia occurring at home in young children with insulin-dependent diabetes mellitus using conventional therapy. DESIGN: Sixty-one children (aged 2.6 to 8.5 years) were studied on one night, at home, with blood collection occurring at dinner, bedtime/supper, 11 PM, 2 AM, and breakfast, with subsequent laboratory analysis. RESULTS: The proportion of subjects with blood glucose levels less than 64, 55, 45, and 36 mg/dl (3.5, 3.0, 2.5, and 2.0 mmol/L) was 37.8%, 17%, 13%, and 8%, respectively. Nocturnal hypoglycemia was associated with younger age (< 5 years 57% vs 5 to 8.5 years 36%; p < 0.001) and lowered glycosylated hemoglobin levels (HbA1c) with a greater than 50% incidence of hypoglycemia seen in subjects with HbA1c levels of less than 8.5%. The average HbA1c concentration was lower in the hypoglycemic group than in the nonhypoglycemic group (7.8 vs 8.3%; p < 0.02). Nocturnal hypoglycemia occurred with increasing frequency throughout the night in subjects less than 5 years of age (dinner, supper, 11 PM, 2 AM, and breakfast incidences being 0%, 12.5%, 26%, 33%, and 30%, respectively) but not in those older than 5 years. Carbohydrate intake at supper did not prevent subsequent hypoglycemia. Blood glucose levels at 11 PM were poor predictors of subsequent hypoglycemia at 2 AM in either the group as a whole or in the children less than 5 years of age. Symptom recognition of nocturnal hypoglycemia was decreased in younger children (< 5 years (36%) > 5 years (58%)), in those with a lower HbA1c, and when hypoglycemia occurred at breakfast rather than at dinner (0% vs 50%). CONCLUSIONS: The incidence of nocturnal hypoglycemia in young children with insulin-dependent diabetes mellitus receiving conventional therapy is unacceptably high and is increased with lowered age and HbA1c concentration; the condition is often asymptomatic. Early-morning hypoglycemia is poorly predicted by a blood glucose determination at 11 PM and is not prevented by carbohydrate intake at supper. In younger children, blood glucose profiles should include early-morning measurements.
Assuntos
Diabetes Mellitus Tipo 1/fisiopatologia , Hipoglicemia/epidemiologia , Fatores Etários , Glicemia/análise , Criança , Pré-Escolar , Ritmo Circadiano , Diabetes Mellitus Tipo 1/tratamento farmacológico , Carboidratos da Dieta/administração & dosagem , Feminino , Hemoglobinas Glicadas/análise , Humanos , Hipoglicemia/diagnóstico , Hipoglicemia/prevenção & controle , Hipoglicemiantes/uso terapêutico , Incidência , Insulina/uso terapêutico , Insulina Isófana/uso terapêutico , Masculino , Valor Preditivo dos TestesRESUMO
OBJECTIVE: Eating simple sugars has been suggested as having adverse behavioral and cognitive effects in children, but a physiologic mechanism has not been established. This study was performed to address this issue. DESIGN: Metabolic, hormonal, and symptomatic responses to a standard oral glucose load (1.75 gm/kg; maximum, 120 gm) were compared in 25 healthy children and 23 young adults, and the hypoglycemic clamp, together with measurements of P300 auditory evoked potentials, was used to assess whether children are more vulnerable than adults to neuroglycopenia. SETTING: Children's Clinical Research Center, Yale University School of Medicine. RESULTS: Baseline and oral glucose-stimulated plasma glucose and insulin levels were similar in both groups, including the nadir glucose level 3 to 5 hours after oral administration of glucose (3.4 +/- 0.1 mmol/L (61 +/- 1.8 mg/dl) in children and 3.5 +/- 0.1 mmol/L (63 +/- 1.8 mg/dl) in adults). The late glucose decrease stimulated a rise in plasma epinephrine levels that was twofold higher in children than in adults (2260 +/- 289 vs 1031 +/- 147 pmol/L (407 +/- 52 vs 186 +/- 26 pg/ml), p < 0.01) and a significant increase in hypoglycemic symptom scores in children (p < 0.01), but not in adults. During control experiments, in which six of the healthy children ingested a sugar-free drink, there were no significant changes in plasma glucose levels, hormone concentrations, or hypoglycemic symptom scores. During the hypoglycemic clamp, P300 potentials did not change in any of eight adult subjects until the plasma glucose concentration was lowered to 3.0 mmol/L (54 mg/dl), whereas similar changes in P300 potentials were observed in six of seven children at glucose levels 3.6 to 4.2 mmol/L (65 to 75 mg/dl). CONCLUSION: Enhanced adrenomedullary responses to modest reductions in plasma glucose concentration and increased susceptibility to neuroglycopenia may be important contributing factors to adverse behavioral and cognitive effects after sugar ingestion in healthy children.