Naturally Occurring Secondary Nutritional Hyperparathyroidism in Cattle Egrets (Bubulcus Ibis) From Central Texas

Abstract

Naturally occurring secondary nutritional hyperparathyroidism is described in the nestlings of two colonies of cattle egrets (Bubulcus ibis) from Central Texas (Bryan and San Antonio, Texas, USA). Nestlings from a third colony (Waco, Texas, USA) were collected in a subsequent year for comparison. Birds from the first two colonies consistently had severe osteopenia and associated curving deformities and folding fractures of their long bones. These birds also had reduced bone ash, increased osteoclasia, a marked decrease in osteoblast activity, variable lengthening and shortening of the hypertrophic zone of the epiphyseal cartilage, decreased and disorganized formation of new bone, and a marked hypertrophy and hyperplasia of the parathyroid glands as compared to birds collected from the third colony. Fibrous osteodystrophy was found in all of the birds from San Antonio and Bryan. Evidence of moderate to severe calcium deficiency was also identified in 33% of the cattle egrets collected from Waco. Gut contents of affected chicks contained predominately grasshoppers and crickets; vertebrate prey items were absent from the Bryan birds. Grasshoppers and crickets collected from fields frequented by the adult egrets in 1994 had 0.12-0.28% calcium and 0.76-0.81% phosphorus. Pooled grasshoppers and crickets collected during a subsequent wet early spring averaged 0.24% calcium and 0.65% phosphorus. Although the phosphorus content of the insect prey was adequate for growth, calcium was approximately one-third the minimum calcium requirement needed for growth for other species of birds. It was postulated that cattle egrets breeding in Central Texas have expanded their range into habitat that contains less vertebrate prey, and as a result, many nestling egrets are being fed diets that contain suboptimal calcium. Therefore, in years where vertebrate prey is scarce and forage for insect prey is reduced in calcium, nestling egrets are at risk for developing secondary nutritional hyperparathyroidism.

Salmonella Enterica Subsp. Enterica in Cattle Egret (Bubulcus Ibis) Chicks From Central Texas: Prevalence, Serotypes, Pathogenicity, and Epizootic Potential

“…Also, a moderate hepatitis was found histologically in birds that were bacteremic with this serotype. The observed hepatitis was not as severe as that reported in a previous study (Phalen et al, 2005), and it was not clear if the observed lesions were sufficient to cause chick mortality in every case. However, these lesions were significant and would have been expected to at least cause morbidity, impacting birds in a critical stage of their development.…”

“…A previous study revealed that 20% of Cattle Egret chicks found in a Central Texas colony had severe hepatitis from which an untyped Salmonella was isolated (Phalen et al, 2005). It was the initial objective of this study to determine if this was a limited observation or if Salmonella infection and disease was a common phenomenon in Cattle Egret chicks in Central Texas.…”

“…In that study 20% of chicks collected from an Egret colony in Central Texas (Bryan, Texas, USA) had a subacute, severe bacterial hepatitis from which an untyped Salmonella was isolated (Phalen et al, 2005).…”

A importância da ordem Ciconiiformes na cadeia epidemiológica de Salmonella spp. para a saúde pública e a conservação da diversidade biológica

“…(Carvalho 2006, Tessari et al 2008), e são comumente envolvidas em casos de gastrenterites e outros tipos de infecções, como febre tifóide, meningites, cistites no Brasil e no mundo (Peresi et al 1998, Millán et al 2004, Nadvorny et al 2004, Fortuna e Franco 2005, Carvalho 2006). Em animais, também são citadas como causadoras de enfermidades com manifestações diversas desde gastroentéricas até septicêmicas, em praticamente todas as classes (Gopee et al 2000, Phalen et al 2005, Carvalho 2006). …”

“…Nos trabalhos internacionais analisados utilizaram-se os meios de cultivo indicados pelo PNSA (Brasil 2002), havendo apenas variação de uso de alguns meios não inclusos neste programa, como Ágar Salmonella-Shigella, Ágar Sangue ou Ágar MacConkey (Smith et al 2002, Rojas et al 2002, Millán et al 2004, Phalen et al 2005, Bada-Alambedji et al 2006. Isto sugere um reconhecimento mundial desses meios como prioritários para isolamento dessas enterobactérias.…”