Measles is caused by a virus from the Paramyxoviridae family and Morbillivirus genus. It is a spherical, pleomorphic virus around 150nm in diameter with an envelope containing glycoproteins and a helical nucleocapsid containing single-stranded RNA. It is transmitted via airborne droplets or direct contact and causes symptoms like fever, rash, red eyes, and white spots in the mouth. The virus replicates in the nasopharynx and lymph nodes before spreading via the bloodstream. Diagnosis involves detecting viral antigens, observing cytopathic effects in cell culture, or serological testing for antibodies.
6. Transmission
Airborne
Direct contact with infected nasal
or throat secretions.
Symptoms
•Fever
•Muscle Pain
•Rash (itchy, red
areas that
spread together)
•Redness and/or
irritation of the
eyes
•Sore throat
•White spots in
the mouth
(Koplik’s spots)
Pleomorphic– has the ability to alter their shape or size in response to environmental conditions
Envelope: Two membrane envelope proteins are important in pathogenesis. They are the F (fusion) protein,, and the H (hemagglutinin) protein,
Very Fragile
Contains G, Haemagglutinin which is responsible for adsorption of virus to cells. ,or HN which
carries hemagglutinin or nueraminidase activity
and fusion ( F) glycoprotein which is responsible for fusion of virus and host cell membranes, viral penetration, and hemolysis
Replication occurs in the cytoplasm.Replication of paramyxovirus is initiated by the binding of The virus binds to glycolipids or proteins and then and fuses with the cell surface. Individual mRNAs for each protein and a full-length template are transcribed from the genome. The nucleocapsid associates with matrix and glycoprotein-modified plasma membranes. Mature virions then leaves the cell by budding.
It is an acute viral infection characterized by a final stage with a maculopapular rash erupting successively over the neck and face, trunk, arms, and legs, and accompanied by a high fever. After 2 days of illness, the typical mucous membrane lesions, known as Koplik’s spots appear. They are seen most commonly on the buccal mucosa across from the molars, but they may appear on other mucous membranes as well, including the conjunctivae and the vagina.
Rubella, also called German measles or three-day measles, is a contagious viral infection best known by its distinctive red rash.
Rubella is not the same as measles (rubeola), though the two illnesses do share some characteristics, including the red rash. However, rubella is caused by a different virus than measles and is neither as infectious nor usually as severe as measles.
The measles-mumps-rubella (MMR) vaccine, usually given to children in the United States twice before they reach school age, is highly effective in preventing rubella. Because of widespread use of the vaccine, the Centers for Disease Control and Prevention (CDC) has declared rubella eliminated in the United States, but cautions parents to make sure their children are vaccinated to prevent its reemergence.
Maculopapular rash-- a type of rash characterized by a flat, red area on the skin that is covered with small confluent bumps.
The term "maculopapular" is a compound: macules are small, flat discolored spots on the surface of the skin; and papules are small, raised bumps.
Respiratory transmission of virus
Replication in nasopharynx and regional lymph node
Primary viremia 2-3 days after exposure
Secondary viremia 5-7 days after exposure w/ spread to tissues
Viremia- presence of virus in the blood.
