Abstract:
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Measles continues to be a major childhood disease in terms of global morbidity and mortality. In the main
areas of its endemicity the only available means of diagnosis are based on clinical criteria: the presence of a
maculopapular rash and fever accompanied by cough, coryza, and/or conjunctivitis. We have studied 38
clinically diagnosed cases of measles in Khartoum, Sudan, by means of serology, reverse transcriptase PCR
(RT-PCR) on throat swabs and virus isolation from lymphocytes. On the basis of serology, 28 patients were
diagnosed as having an acute measles virus (MV) infection, while in 10 cases the clinical symptoms proved to
have other causes. It was shown that in cases with low serum immunoglobulin M (IgM) levels, an additional
measurement of IgG or virus-neutralizing antibodies was necessary to discriminate between patients with an
acute MV infection sampled during an early stage of the disease and patients who had experienced an MV
infection in the more distant past. The serological laboratory diagnosis was validated by an MV-specific
RT-PCR: for all confirmed measles cases tested a fragment of the correct size which hybridized with a third
MV-specific primer could be amplified, while all serologically negative cases were also RT-PCR negative. MV
could be isolated from 17 out of 23 of the serologically confirmed cases, demonstrating that virus isolation is
less reliable as a diagnostic tool than serology or RT-PCR. This study stresses the urgent need for a rapid
diagnostic field test for measles. |