Role of oral-fluid based measles diagnostic methods for measles global elimination

Table 1 Samples for laboratory diagnosis of measles virus infections

Virus disease	Samples for virus isolation for detection of antigen	Samples for serology	Remarks
Acute measles	Blood (leukocytes), throat secretions (saliva/oral-fluid), conjunctival secretions, urine; skin biopsies	Acute and convalescent serum	Period of infectivity; prodromal stage until 1-2 d after rash; antibody rises occur at appearance of rash; in tropical measles, possibly prolonged virus excretion also in stools
Measles pneumonia	Blood (leukocytes), throat secretions, conjunctival secretions, urine	Acute and convalescent serum	Frequently no rash; prolonged period of infectivity
Acute measles encephalitis	Brain specimen (biopsy or autopsy specimen), cells in CSF	Serum and CSF	In most cases, no infectious virus is detectable; occasional local production of antibodies in the CNS
SSPE	Brain specimen (biopsy or autopsy specimen), cells in CSF, lymph node biopsy (?)	Serum and CSF	Virus antigen detected in CSF cell; virus isolation requires propagation of explants cultures and cocultivation with susceptible cells; hyper-immune antibody response; local production of antibodies in the CNS

Modified from Norrby et al[137]. CSF: Central spinal fluid; CNS: Central nervous system.

Table 2 Application of oral-fluid methods under different countries settings

Applications of oral-fluid methods	Setting for country/district
	Low /Med uptake routine	High uptake routine	Campaign
Population survey	Methods: community surveys of IgG across wide age range. Including hard-to-reach groups, informal settlements. Purpose: immunity profiles. Identifies susceptibility gaps and age range for campaigns. Implications: increase in coverage, need for and age range for campaigns	As previous	As previous plus. Methods: Post-campaign surveys of IgG and perhaps IgM. Purpose: IgG-Identify immunity levels post-campaign. Susceptibility in target age group and outside target group. IgM-indicator of impact, i.e., proportion responding to vaccine. Implications: Age-range for future campaigns; locate problems of vaccine efficacy
Vaccine surveys	Methods: Vaccine clinic samples pre- and post-vaccination. IgM and/or IgG testing. Purpose: Assess efficacy of routine vaccination. Implications: Identify cause of low efficacy.	As previous	As previous plus. Methods: IgG survey of individuals attending vaccine clinics. Purpose: Identify proportion able to respond to vaccine. Implications: Assess potential effectiveness, and suggest alternative method for delivery eg hard-to-reach groups.
Diagnosis	Not indicated while measles incidence remains high	Method: IgM testing on demand. Purpose: Confirmation of clinical diagnosis	As previous
Case surveillance: serological and genetic	Not indicated while measles transmission remains high	Method: System of reporting and oral fluid sampling from sporadic cases and outbreaks. IgM and Genotyping Purpose: Verify cases, and monitor distribution of virus and endemicity Implications: Need for additional control measures	As previous

IgG: Immunoglobulin G; IgM: Immunoglobulin M.