Confirmation by laboratory testing of clinically suspected cases of measles and rubella is recommended as clinical diagnosis can be unreliable since symptoms can be mimicked by other viruses (eg. Parvovirus B19, enteroviruses etc). Other samples for virological investigation should be collected in consultation with the laboratory.
Patients with suspected measles or with clinical symptoms of measles infection (i.e. morbilliform rash, cough and fever at rash onset) within a few days (<5 days) after rash onset, should be sampled for diagnostic testing.
Virus is more likely to be present at the time of rash onset or within the first week after rash onset.
The specimen of choice is a nasopharyngeal swab in a vial of universal transport medium (UTM). Recovery of a virus will allow genotyping and the identification of both wild-type virus or vaccine strains.
Blood samples (5ml plain blood or serum) should be collected day 3 and onwards following rash onset for IgM and IgG antibody detection.
Timing and choice of sample is important for accurate diagnosis.
Universal Transport Medium (UTM): Viral transport medium usually consisting of sterile Hanks balanced salt solution and antibiotics to reduce bacterial contamination growth. To be used for sample collection with nasopharyngeal swabs. UTM should be available from your laboratory service provider or nearest virus laboratory.
Dry swabs or swabs placed into gel type transport media ARE NOT SUITABLE for recovery of viral RNA and are not recommended.
Samples should be transported to the laboratory strictly in accordance with the IATA dangerous regulations for transporting biological specimens within New Zealand. Samples should be kept at 4°C whenever possible. All samples must be accompanied by either a copy of the public health notification form or the New Zealand National Measles Laboratory Form.