MEASLES

 

INTRODUCTION: Measles is a highly contagious, acute, febrile illness. In the developing countries it has the highest morbidity and mortality among all vaccine preventable illnesses. Measles is one of the most ubiquitous and persistent of human viruses. Its distribution is worldwide and it causes disease in any climate and under any conditions, provided enough susceptible human beings are brought together to enable it to spread.

CLINICAL FEATURES: Measles is one of the most important childhood infections. After an incubation period of 10-12 days, the disease manifests with prodromal symptoms of fever and upper respiratory tract infection marked with coryza, cough and conjunctivitis. Early diagnosis can be made by detecting Koplik’s spots, which are red macules or ulcers with a bluish white centre, seen on the mucous membrane of the inside of cheek. Rashes appear on different parts of the body starting from head followed by chest, trunk and then limbs. After a few days they start fading and then recovery is rapid and complete. Measles can cause severe and multiple complications in a large number of patients (10-20%). Encephalomyelitis has an incidence of less than one out of 1000, but carries a mortality of 15%. It also has sequelae of epilepsy and personality changes.

PATHOGENESIS: Measles, like mumps, is a typical systemic viral infection. Virus gains entry through respiratory tract, multiplies in the epithelial lining and then spreads to lymph nodes where another phase of replication occurs. Further spread to organs takes place and skin, brain and lungs get involved. Lesions produced are characterised by the presence of multinucleated giant cells with well defined intranuclear and intracytoplasmic inclusions. It is now well established that the maculopapular rash of measles is mediated by immunopathological mechanism. Such rashes do not appear in immunologically compromised patients who develop pneumonia and in case of adults, the disease proves fatal.

IMMUNE RESPONSE: High titres of IgG, IgM as well as secretory IgA are seen after primary infection with measles virus. IgM and IgA disappear after sometime but IgG persist lifelong making the individual immune to reinfection. Though a strong immune response is mounted by the body on getting infected with measles virus, the disease has got an immunosuppressive action.

LABORATORY DIAGNOSIS: Clinical Samples: Diagnosis of a typical case of measles can be made based upon clinical symptoms. However, demonstration of the virus or seroconversion against the virus is necessary to confirm the diagnosis. Best results for isolation of virus are obtained when specimens are taken during the first few days of illness.

RELATED;

1.  MUMPS

2.  HEPATITIS

3.  MEDICAL CONDITIONS

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