Whooping Cough (pertussis), caused by the bacterium Bordetella pertussis, is a relatively mild disease in adults but has a significant mortality rate in infants.
The incidence of this disease in developed countries declined dramatically after vaccines were introduced in the mid 1940s. However, since 1980 the incidence of pertussis has been rising and today it is regarded as a re-emerging disease.
Infants and young children continue to have the highest rates of pertussis, although these rates have not increased. However, the incidence among adolescents and adults has increased substantially. Investigations of outbreaks have documented that adults develop infection and then transmit the organism to susceptible children or other adults. Thus, previously immunized adults and adolescents are the main source of transmission of Bordetella pertussis.
Though vaccination is highly effective for young children, immunity diminishes in many adolescents and adults and no vaccine has been developed for these age groups.
It is rather difficult to diagnose pertussis infection in adults since the infection may have an atypical presentation with a modified clinical course. This may lead to under diagnosis and delayed treatment or lack of treatment all together.
Pertussis-like coughing can be caused by other pathogens, e.g., Mycoplasma pneumoniae, Chlamydia pneumoniae and adenoviruses. Therefore, the diagnosis of pertussis, particularly in the vaccinated population, relies mainly on laboratory confirmation.
Culture of Bordetella pertussis is laborious, insensitive and highly dependent on sample collection and transportation. Also, pertussis is not suspected in adults until they have had a prolonged period of coughing. Thus, very little organism is left in the nasopharynx when the culture is obtained and consequently no organism is isolated. Similarly, the PCR assay sensitivity rapidly decreases during the diseases progression.
ELISA-based serology is the main approach used for laboratory diagnosis with Pertussis toxin (PT) and filamentous hemagglutinin (FHA) as the preferred antigen combination.
The detection of specific IgA and IgM antibodies is indicative of acute infection and is useful for the differential diagnosis of pertussiform syndromes of longer duration. Infants do not regularly produce IgA antibody before 6 months of age, so instead, specific IgM antibodies can be used in infants as an indicator of acute infection. IgG antibodies can be used to diagnose active infection when paired sera are available and a rise in antibody level can be demonstrated.
The SeroPertussis™ product line utilizes PT and FHA as antigens for detecting antibodies to Bordetella pertussis in human serum.
SeroPertussis™ IgG is a semi-quantitative kit using 3 built-in calibrators - P10, P50 and P100 – to draw a calibration curve correlating O.D. readings and BU/ml units.
SeroPertussis™ IgA/IgM is a qualitative kit designed to provide flexibility in detecting IgA and/or IgM antibodies.
SeroPertussis™ Toxin IgA is a quantitative Enzyme Linked Immunosorbent assay (ELISA) for the determination of specific IgA antibodies to Bordetella pertussis Toxin.
SeroPertussis™ Toxin IgG is a quantitative Enzyme Linked Immunosorbent assay (ELISA) for the determination of specific IgG antibodies to Bordetella pertussis Toxin