Assessment of the ability of ratite-origin influenza viruses to infect and produce disease in rheas and chickens.
Pathobiologic characteristics were determined for three mildly pathogenic (MP) ratite-origin avian influenza viruses (AIVs). Ratite-origin AIVs produced respiratory disease in rheas, and virus was reisolated from oropharyngeal and cloacal swabs on days 2-6 postinoculation. Inoculation of two ratite-origin AIVs in the upper respiratory tract of chickens resulted in viral infections, but the mean chicken infectious…Read More
Combined adenovirus and rotavirus enteritis with Escherichia coli septicemia in an emu chick (Dromaius novaehollandiae).
A 2-week-old emu chick (Dromaius novaehollandiae) of approximately 200 g body weight was presented for necropsy with a history of weakness, diarrhea, pallor of the head, and acute death. Hemorrhagic enteritis with mild hepatomegaly was noted on gross examination. Microscopic examination revealed necrohemorrhagic enteritis with intralesional intranuclear basophilic viral inclusion bodies in intestinal epithelial cells;…Read More
Changes in pattern of heat loss at high ambient temperature caused by water deprivation in a large flightless bird, the emu.
When exposed to high ambient temperatures, birds defend body temperature by increasing evaporative water loss, via either respiratory or cutaneous water loss. Water deprivation can lead to changes in thermal responses and lower levels of water use for thermoregulation. We have studied the effect of 2-3 wk of water deprivation on the physiological responses of…Read More
A neuroendocrine model for prolactin as the key mediator of seasonal breeding in birds under long- and short-day photoperiods.
Seasonal breeding is associated with sequential increases in plasma luteinizing hormone (LH) and prolactin in the short-day breeding emu, and in long-day breeding birds that terminate breeding by the development of reproductive photorefractoriness. A model of the avian neuroendocrine photoperiodic reproductive response is proposed, incorporating a role for prolactin, to account for neuroendocrine mechanisms controlling…Read More
Cardiovascular changes in the exercising emu.
Cardiovascular variables were studied as a function of oxygen consumption in the emu, a large, flightless ratite bird well suited to treadmill exercise. At the highest level of exercise, the birds’ rate of oxygen consumption (VO2) was approximately 11.4 times the resting level (4.2 ml kg-1 min-1). Cardiac output was linearly related to VO2, increasing…Read More
Cardiac rhythms in prenatal and perinatal emu embryos.
Emu eggs weigh approximately 600 g and have an incubation duration (ID) of approximately 50 days. The egg mass is approximately 10-fold heavier than the chicken egg and the ID is approximately 2.5-fold longer. Daily changes in mean heart rate (MHR) of emu embryos were previously determined, but further measurement was needed to investigate the…Read More
A DNA test to sex ratite birds.
DNA-based sex tests now exist for many avian species. However, none of these tests are widely applicable to ratites. We present DNA sequence data for a locus that is W chromosome-linked in the kiwi, ostrich, cassowary, rhea, and emu. At the amino acid level, this sequence has significant homology to X-linked genes in platyfish and…Read More
Encephalomalacia associated with vitamin E deficiency in commercially raised emus.
Thirteen of 64 emus on a commercial emu farm in Ohio exhibited neurological signs that included backward staggering, incoordination, generalized weakness, and sitting on their hocks with head retracted backward. Eight of the birds showing such signs were found dead. Two of these emus were necropsied, and no significant gross lesions were observed. Major histopathological…Read More
Eastern equine encephalitis transmission to emus (Dromaius novaehollandiae) in Volusia County, Florida: 1992 through 1994.
From May 1992 through October 1994, sera were collected from 204 domestic emus (Dromaius novaehollandiae) at a ranch in Volusia County, FL, and tested for antibody evidence of arboviral infection. Hemagglutination-inhibition (HI) and neutralizing (NT) antibodies to eastern equine encephalitis (EEE) virus were identified in sera collected during each year. In addition, HI and NT…Read More
Detection of eastern equine encephalomyelitis virus RNA in formalin-fixed, paraffin-embedded tissues using DNA in situ hybridization.
Eastern equine encephalomyelitis (F.EE) virus was detected in infected formalin-fixed horse and emu tissues and in infected chicken embryo fibroblasts. Results of in situ hybridization using a digoxigenin-labeled 40-base DNA probe complementary to a conserved region of the EEE virus RNA compared favorably with results of both virus isolation and serum neutralization tests. This technique…Read More