Genotyping

Molecular epidemiology has been used to complement and extend traditional epidemiological methods of measles contact tracing.
Molecular epidemiological evidence generated at VIDRL has been used to determine the source of measles virus importation in recent Victorian outbreaks.

VIDRL also provides molecular surveillance to other Australian states to assist identification of sources of measles virus importation:

Chibo D, Riddell MA, Catton MG, Lyon M, Lum G, Birch CJ. Studies of measles viruses circulating in Australia between 1999 and 2001 reveals a new genotype. Virus Res 2003; 91:213-221

VIDRL has identified and described 3 new measles genotypes imported into Australia and causing outbreaks here:

Chibo D, Birch C, Rota PA and Catton M. 2000. Molecular characterisation of measles viruses isolated in Victoria, Australia, between 1973 and 1998. J. Gen. Virol. 81: 2511-2518
Chibo D, Riddell M, Catton MC, and Birch C. 2002. Novel measles virus genotype, East Timor and Australia. Emerg Infect Dis 8:735-7
Chibo D, Riddell MA, Catton MG, Lyon M, Lum G, Birch CJ. Studies of measles viruses circulating in Australia between 1999 and 2001 reveals a new genotype. Virus Res 2003; 91:213-221

Testing by PCR at VIDRL of specimens collected from serologically confirmed measles cases has shown that the virus can be detected in the upper respiratory tract in approximately 70% of cases for at least 2 weeks after onset of rash (see diagram):

Riddell MA, Chibo D, Kelly HA, Catton MG, and Birch CJ. 2001. Investigation of optimal specimen type and sampling time for detection of measles virus RNA during a measles epidemic. J Clin Microbiol 39:375-376

 

Percentage of measles IgM positive specimens with positive PCR result

click diagram to view full size version