Concurrent measles infection of cynomolgus monkey during a Reston Ebola virus outbreak in the Philippines

Abstract

Purpose: Measles virus (MV) infections is still a major cause of vaccine-preventable childhood deaths worldwide. In the Philippines, an outbreak of measles virus occurs every 2 to 3 years. In 2015, a non-human primate facility noted unusual deaths of 6 cynomolgus monkeys (Macaca fascicularis), characterized by generalized rashes and sudden death. This is the first report of concurrent outbreaks of Measles and Reston Ebola virus among non-human primates in the Philippines. Methods & Materials: 174 serum samples were collected from macaques in the quarantine facility and were tested for MV antibody by Enzygnost Measles Anti-IgM ELISA (Siemens, Healthcare Diagnostics, Germany). The serum samples were diluted in rheumatoid factor absorbent to remove inhibitors that might interfere with the reaction. A TaqMan RT-PCR assay was performed to amplify partial N gene of MV from serum samples. Likewise, amplification of the partial L gene of MV RNA and sequencing of the product was done. Results: A total of 174 serum samples were tested with 8 samples with anti-MV IgM detected. Also, 1 sample was positive for MV RNA using RT-PCR and was subjected to sequencing. One macaque was found to have both anti-RESTV and anti-MV while another one had dual infection of RESTV and MV as detected by PCR. Phylogenetic analysis of the partial L gene using Mega 6 showed that the MV belonged to genotype B3, the same genotype that caused a large outbreak in the Philippines in 2014. Conclusion: Measles virus was detected in non-human primates in the Philippines during a RESTV outbreak in a non-human primate quarantine facility. Human to non-human primate MV were reported in quarantine facilities and wildlife parks in other countries. Considering the high risk of MV infection in macaques associated with human MV outbreak in the Philippines, further studies are required to mitigate the transmission.