The epithelium sticks to the basement membrane, which also separates the epithelium from the stroma. The corneal stroma comprises 90 percent of the thickness of the cornea. It contains the collagen fibers organized into lamellae. The lamellae are in sheets which separate easily. Posterior to the stroma is Descemets membrane, which is a basement membrane for the corneal endothelium. The endothelium is a single cell layer that separates the cornea from the aqueous humor. Corneal healing
A healing of a corneal ulcer involves two processes: migration of surrounding epithelial cells followed by mitosis (dividing) of the cells, and introduction of blood vessels from the conjunctiva. Superficial small ulcers heal rapidly by the first process. However, larger or deeper ulcers often require the presence of blood vessels to supply inflammatory cells. White blood cells and fibroblasts produce granulation tissue and then scar tissue, effectively healing the cornea. Superficial and deep corneal ulcers
Corneal ulcers are one of the most common eye diseases in dogs. They are caused by trauma, detergent burns, and infections. Other eye conditions can cause corneal ulcers, such as entropion, distichiae, corneal dystrophy, and keratoconjunctivitis sicca (dry eye). There have been at least two cases where corneal ulceration was caused by canine herpesvirus.Superficial ulcers involve a loss of part of the epithelium. Deep ulcers extend into or through the stroma and can result in severe scarring and corneal perforation. Descemetoceles occur when the ulcer extends through the stroma, exposing Descemets membrane. This type of ulcer is especially dangerous and can result in perforation.
Post infection (and providing that the person survives the infection), those that have contracted BHF are usually immune to further infection of the disease. Weaponization
Bolivian hemorrhagic fever was one of three hemorrhagic fevers and one of more than a dozen agents that the United States researched as potential biological weapons before the nation suspended its biological weapons program in 1969. Albert Nickel, a 53-year old animal caretaker at Fort Detrick, died in 1964 from the disease after being bitten by an infected mouse. Nickel Place, on Fort Detrick, is named in his honor. It was also under research by the Soviet Union, under the Biopreparat bureau. Vaccine research
Investigational vaccines exist for Argentine hemorrhagic fever and RVF; however, neither is approved by FDA or commonly available in the United States.The structure of the attachment glycoprotein has been determined by X-ray crystallography and this glycoprotein is likely to be an essential component of any successful vaccine. References
Bibliography

Medical Microbiology 2nd Edition Mims et al. Mosby Publishing 1998 p 371


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