A genetic investigation of two men found to have asymptomatic MERS-CoV infections after exposure to sick camels supports zoonotic exposure as a transmission route.
Gene sequences from the camels and the men, combined with the epidemiologic findings, strongly suggest zoonotic transmission, but the team said they couldn’t rule out the remote possibility that the camels and men were infected from independent sources.
The investigators said the findings help build the case that asymptomatic infections can result from animal transmission, though they added that it’s not clear if such infections can fuel transmission among humans.
Sequences from the camels and the men were similar to those recently detected in Saudi Arabia and South Korea, according to the study. Although there is no sign the clade is more transmissible, the fact that a single introduction triggered such a gush of cases in South Korea warrants further genetic risk assessment, the team wrote.