Among the preferred species within these families are the American crow, a corvid, and the American robin (Turdus migratorius).Some species of birds develop sufficient viral levels (>~104.2 log PFU/ml;) after being infected to transmit the infection to biting mosquitoes that in turn go on to infect other birds. In birds that die from WNV, death usually occurs after 4 to 6 days. In mammals and several species of birds, the virus does not multiply as readily and so does not develop high viremia during infection. Mosquitoes biting such hosts are not believed to ingest sufficient virus to become infected, making them so-called dead-end hosts. As a result of the differential infectiousness of hosts, the feeding patterns of mosquitoes play an important role in WNV transmission, and they are partly genetically controlled, even within a species.Direct human-to-human transmission initially was believed to be caused only by occupational exposure, such as in a laboratory setting, or conjunctival exposure to infected blood. The US outbreak identified additional transmission methods through blood transfusion, organ transplant, intrauterine exposure, and breast feeding. Since 2003, blood banks in the United States routinely screen for the virus among their donors. As a precautionary measure, the UKs National Blood Service initially ran a test for this disease in donors who donate within 28 days of a visit to the United States, Canada, or the northeastern provinces of Italy, and the Scottish National Blood Transfusion Service asks prospective donors to wait 28 days after returning from North America or the northeastern provinces of Italy before donating.
Limb body wall complex (LBWC) is a rare fetal malformation of unknown origins. Traditionally diagnosis has been based on the Van Allen et al., criteria, i.e. the presence of two out of three of the following anomalies:
Exencephaly or encephalocele with facial clefts
Thoraco and or abdominoschisis and
Limb defects.LBWC occurs in approximately 0.32 in 100,000 births.At this time, there is no known cause of Limb Body Wall Complex. However, there have been tentative links made between a diagnosis of LBWC and cocaine use. In addition, current research has shown that there may be a genetic cause for a small limited number of LBWC cases.Limb Body Wall Complex is a lethal birth defect. There are only anecdotal stories of survivors. == References ==