** Horses After inoculation by the vector, the virus travels via lymphatics to lymph nodes, and replicates in macrophages and neutrophils, resulting in lymphopenia, leukopenia and fever. Subsequent replication occurs in other organs leading to viremia. Symptoms in horses occur one to three weeks after infection, and begins with a fever that may reach as high as 106 °F (41 °C). The fever usually lasts for 24–48 hours. Nervous signs appear during the fever that include sensitivity to sound, periods of excitement, and restlessness. Brain lesions appear, causing drowsiness, drooping ears, circling, aimless wandering, head pressing, inability to swallow, and abnormal gait. Paralysis follows, causing the horse to have difficulty raising its head. The horse usually suffers complete paralysis and death two to four days after symptoms appear. Mortality rates among horses with the eastern strain range from 70 to 90%. **Humans In humans, symptoms include high fever, muscle pain, altered mental status, headache, meningeal irritation, photophobia, and seizures, which occur three to 10 days after the bite of an infected mosquito. **Prevention The disease can be prevented in horses with the use of vaccinations. These vaccinations are usually given together with vaccinations for other diseases, most commonly WEE, VEE, and tetanus. Most vaccinations for EEE consist of the killed virus. **Treatment and prognosis Magnetic resonance images (MRIs) and computed tomography (CT) neuro radiographs showing lesions in brains of 3 children with eastern equine encephalitis. A) Results of noncontrast CT scan of the brain of patient 12 on hospital day 2; the neuro radiograph shows subtle hypoattenuation of the left caudate head (arrow) and diencephalic region. Axial fluid attenuated inversion recovery (FLAIR) image from brain MRI scan of patient 14 on hospital day 2; the image shows abnormal T2 hyperintense regions of the bimesial temporal regions (thick arrows) with accompanying abnormal T2 hyperintense regions of the dorsal pontomesencephalic regions (thin arrows). C, D) FLAIR images from brain MRI scan of patient 15 on hospital day 3. C) Abnormal T2 hyperintense caudate and thalamic nuclei, most prominent on the right (arrow). D) Abnormal T2 hyperintense regions are most prominent in the right parietal temporal gray matter (arrow) and subcortical white matter but are also seen scattered throughout. **There is no cure for EEE. Treatment consists of corticosteroids, anticonvulsants, and supportive measures (treating symptoms)[2] such as intravenous fluids, tracheal intubation, and antipyretics.[citation needed] About four percent of humans known to be infected develop symptoms, with a total of about six cases per year in the US.[2] A third of these cases develop permanent brain damage.
Posted on: Thu, 18 Jul 2013 04:42:20 +0000
Trending Topics
Recently Viewed Topics
© 2015