MBV forms single or multiple spherical, eosinophilic occlusion bodies in hypertrophied nuclei. Diagnosis of MBV can be made by observation of the occlusion bodies in a wet mount of the hepatopancreas. The nuclear membrane is so persistant and will hold multiple occlusion bodies. The virus can be passed in the intact nuclear membrane through the digestive tract of the shrimp and can be viewed by histology in the lumen of the gut. The severity of infections seems to decrease after PL-25.
Mortality rates are variable with the conditions the shrimp are subjected to.
It has also been found in Kuwait, Oman, Israel, Italy, Kenya, and Gambia. It has not been found in the local populations of penaeids in the United States. Disease risk posed by MBV to native shrimp stocks of the Gulf of Mexico is unkown. The best approach to preventing introduction of a virus into a culturing facility is to implement strict biosecurity measures including histological examination of all incoming stock. C.M. Fauquet, D.L. Knudson, and F. Brown.