Avian metapneumovirus subtypes circulating in Brazilian vaccinated and nonvaccinated chicken and turkey farms.

Avian metapneumovirus (AMPV) causes turkey rhinotracheitis and is associated with swollen head syndrome in chickens, which is usually accompanied by secondary infections that increase mortality. AMPVs circulating in Brazilian vaccinated and nonvaccinated commercial chicken and turkey farms were detected using a universal reverse transcriptase (RT)-PCR assay that can detect the four recognized subtypes of AMPV. The AMPV status of 228 farms with respiratory and reproductive disturbances was investigated. AMPV was detected in broiler, hen, breeder, and turkey farms from six different geographic regions of Brazil. The detected viruses were subtyped using a nested RT-PCR assay and sequence analysis of the G gene. Only subtypes A and B were detected in both vaccinated and nonvaccinated farms. AMPV-A and AMPV-B were detected in 15 and 23 farms, respectively, while both subtypes were simultaneously found in one hen farm. Both vaccine and field viruses were detected in nonvaccinated farms. In five cases, the detected subtype was different than the vaccine subtype. Field subtype B virus was detected mainly during the final years of the survey period. These viruses showed high molecular similarity (more than 96% nucleotide similarity) among themselves and formed a unique phylogenetic group, suggesting that they may have originated from a common strain. These results demonstrate the cocirculation of subtypes A and B in Brazilian commercial farms.

Long-term effects of diagnostic ultrasound during fetal period on postnatal development and adult behavior of mouse.

Pregnant Swiss albino mice were exposed to diagnostic levels of ultrasound (3.5 MHz, intensity 65 mW, I(SPTP) = 1 W/cm(2), I(SATA) = 240 W/cm(2)) for 10, 20 and 30 minutes on day 14 of gestation. Sham exposed controls were maintained for comparison. Fifteen pregnant mice were exposed for each group. Exposed as well as control animals were left to complete gestation and parturition. Ultrasound induced changes in maternal vaginal temperature was recorded. The changes in the physiological reflexes and postnatal mortality up to 6 weeks of age were recorded. The litters were subjected to behavioral tests for locomotor activity, learning and memory at 4 month and 1 year of age. Neither the physiological reflexes nor the postnatal mortality was affected by ultrasound exposure. However, there was a noticeable impairment in both locomotor and learning behavior even after a 10 min exposure, which further increased with increases in exposure time. Thus the present study demonstrates the neurotoxicity of diagnostic ultrasound and the high susceptibility of early fetal brain to induction of lasting detrimental changes by ultrasound exposure.

Long-term effects of diagnostic ultrasound during fetal period on postnatal development and adult behavior of mouse

Pregnant Swiss albino mice were exposed to diagnostic levels of ultrasound (3.5 MHz, intensity 65 mW, I(SPTP) = 1 W/cm(2), I(SATA) = 240 W/cm(2)) for 10, 20 and 30 minutes on day 14 of gestation. Sham exposed controls were maintained for comparison. Fifteen pregnant mice were exposed for each group. Exposed as well as control animals were left to complete gestation and parturition. Ultrasound induced changes in maternal vaginal temperature was recorded. The changes in the physiological reflexes and postnatal mortality up to 6 weeks of age were recorded. The litters were subjected to behavioral tests for locomotor activity, learning and memory at 4 month and 1 year of age. Neither the physiological reflexes nor the postnatal mortality was affected by ultrasound exposure. However, there was a noticeable impairment in both locomotor and learning behavior even after a 10 min exposure, which further increased with increases in exposure time. Thus the present study demonstrates the neurotoxicity of diagnostic ultrasound and the high susceptibility of early fetal brain to induction of lasting detrimental changes by ultrasound exposure.