**5. References**

154 Non-Flavivirus Encephalitis

(Yanai et al., 2003b). As the most severely affected area was the olfactory bulb, the virus inoculated into the nasal cavity gained access to the olfactory bulb and then progressed along the rhinencephalon over time. In our study, all of the marmosets inoculated intranasally had severe rhinitis with intranuclear inclusions, and EHV-9 antigen was detected in the olfactory epithelium and glands. From these findings, the EHV-9 inoculated into the nasal cavity presumably multiplied in the olfactory mucosa, and then intruded into the nerve sheath connected to the olfactory bulb, going through the foramina in the cribriform plate of the ethmoid bone. As the olfactory epithelium is usually covered by secreta produced in the olfactory glands, the question remains of how the virus infected the epithelial and glandular cells. The inclusion body formation in the glandular epithelium indicated that a large amount of EHV-9 virus had multiplied in the olfactory glands and shed into the nasal cavity. This suggests that, once EHV-9 has infected the nasal mucosa, the marmoset sheds a large enough quantity of virus for transmission to another animal when contact occurs. In addition, a smaller amount of the virus may cause rhinitis with viral propagation once the virus intrudes into the nasal cavity. However, in the present study, it was not clear how the nerve axons were affected by the EHV-9 in the olfactory mucosa, or

The study demonstrated that marmosets can be infected by a larger dose of EHV-9 by the intranasal route. It suggests the possibility that EHV-9 might be transmitted to other primates, including macaques, great apes and humans. EHV-9 might also be easily transmitted via the nasal route to immuno-compromised animals and patients such as AIDS patients. A recent study showed that Burchell's zebras (*Equus burchelli*) in Tanzania had a high seroprevalence to EHV-9 or to viruses serologically similar to EHV-9 (Borcher et al., 2005), which suggested that EHV-9 is present in zebras permanently residing in East Africa. Also, there has been some possibility of an outbreak of EHV-9 infection as an emerging

One male and four female cynomolgus macaques were obtained from a commercial breeder (Kodama et al., 2011). All of the animals were free from pathogens such as salmonella and *Mycobacterium spp*. and passed the viral antibody tests for B virus and measles virus. The animals were divided into two groups consisting of Nos. 1 and 2 in one group and Nos. 3 and 4 in the other, and the two groups were inoculated intranasally with 1 ml of EHV-9 virus solution containing 103 and 106 plaque-forming units, respectively. The virus fluid was prepared by propagating the fifth passage of the original stock, which is in Madin-Darby bovine kidney (MDCK) cells, in fetal horse kidney cells. The infectivity of the inoculums was confirmed by virus plaque assay with MDCK cells. As a control, cynomolgus monkey No. 5 was inoculated with 1 ml of minimal essential medium. Animals Nos. 1 and 3 were euthanized in accordance with animal welfare regulations on 6 dpi. The other animals were

In contrast with the control animal, the inoculated animals began avoiding light starting from 4 dpi. Blood studies showed no hematological abnormalities in any of the animals. At necropsy, no significant abnormalities were observed in any organs from any of the

Histopathologically, no significant pathological changes were observed in any of the organs from any of the animals. Immunohistochemistry revealed no positive reactions in any of the

how the virus in the nerve sheath migrated to the olfactory bulb.

infection in immuno-compromised animals and patients.

**3. Cynomolgus macaques** 

euthanized on 10 dpi.

animals.


**8** 

**Subacute Sclerosing Panencephalitis and** 

Fernandez-Muñoz R.\*, Carabaña J.1, Caballero M.1, Ortego J.2, Liton P.B.1, Duque B.M, Martin-Cortes A.3, Serrano-Pardo A., Muñoz-Alia M.A.,

Measles virus (MV) is a human, negative-stranded RNA virus, member of the Paramyxoviridae family, genus Morbillivirus. The virus enters cells by interaction of viral glycoprotein Hemagglutinin (H) with cellular receptors (CD46, CD150, CD147/EMMPRIN) and membrane fusion is mediated by viral fusion glycoprotein (F); helical nucleocapsids replicate in the cytoplasm on replication-transcription complexes formed by the viral catalytic subunit (L), the phosphoproteín (P) and the RNA wrapped in the viral nucleoprotein (N); virus particles bud out from plasmatic cell membrane patches internally lined by viral matrix protein(M). MV causes cytopathic effects by cell fusion forming syncytia, by inducing apoptosis, or both together, and may produce persistent infections in cultured cells and in the infected host. MV is highly lymphotropic infecting macrophages, lymphocytes and dendritic cells; causes systemic acute infections after cell-associated

Despite the availability of an efficient live attenuated vaccine, MV still remains an important global pathogen infecting over 25 millions individuals and causing over 250.000 deaths per year, being one of the main causes of child death worldwide. Plans for the global eradication of measles are hindered by a number of factors: 1. high contagiousness of MeV (it is the most transmissible respiratory virus known, and it is needed a 95% to 98% protection in a population to avoid measles out-brakes), 2. vaccination fails in over 5% of the general population (non-responders), 3. vaccination has a low efficiency in infants under 9 months, 4. poor health care in some countries, and 5. objection to vaccination in sectors of the

*Virology Unit ( Madrid and Nacional Reference Laboratory for Measles Virus) Ramón y Cajal University* 

*2 Present address: Animal Health Research Center (CISA-INIA),Valdeolmos, Madrid, Spain* 

viremia generating life-long immunity (Griffin, 2007 for a review).

*1 Present address: Duke University Medical Center, Durham, NC, USA* 

*3 Present address: Complutense University of Madrid. Madrid, Spain 4 Neurology Department, Ramón y Cajal University Hospital, Madrid, Spain* 

**1. Introduction** 

population.

*Hospital, Madrid, Spain* 

*\* Corresponding authors* 

**Other Lethal Encephalitis Caused by** 

**and New Approaches to Treatment** 

**Measles Virus Infection: Pathogenesis** 

Porras-Mansilla R., Alvarez-Cermeño J.C.4 and Celma M.L.\*

