RUBELLA VIRUS – MORPHOLOGY, RESISTANCE, CULTIVATION, PATHOGENESIS, CLINICAL FEATURES, LABORATORY DIAGNOSIS & PROPHYLAXIS

INTRODUCTION TO RUBELLA VIRUS

⇒ RUBELLA VIRUS is the causative agent of disease Rubella or German measles, a mild exanthematous fever which may be acquired Congenitally or Postnatally.

⇒ It was first described by an Australian Ophthalmologist Gregg in 1941 & was first isolated in tissue cultures in 1962.

⇒ This virus belongs to the Rubivirus genus of Togaviridae Family.

MORPHOLOGY OF RUBELLA VIRUS

⇒ Rubella virus is pleomorphic, roughly spherical & enveloped particle.

⇒ Envelope carries the Hemagglutinin peplomers.

⇒ Size: 50-70 nm in diameter.

⇒ Genetic Material:- ssRNA.

RESISTANCE SHOWN BY RUBELLA VIRUS

⇒ Rubella virus is heat labile – destroyed by eating at 56°

⇒ It is inactivated by Ether, Chloroform & Formaldehyde.

⇒ It can survive at -56°C for several years.

CULTIVATION OF RUBELLA VIRUS

⇒ It can be grown in many primary cell tine cultures & continuous cell line cultures, Such as,

• Rabbit Kidney (RK 13)
• Baby Hamster Kidney (BHK 21)
• Vero cell cine culture.
• Human Amnion tissue culture.
• Human thyroid tissue culture

PATHOGENESIS OF RUBELLA VIRUS

⇒ Rubella virus is the causative agent of disease Rubella or German measles, a mild exanthematous fever characterized by transient macular rash and Lymphadenopathy.

The infection of Rubella is acquired

by inhalation.

⇓

The replication of virus occurs in

Cervical lymph nodes.

⇓

Viremia occurs and can be demonstrated

As early as the 7^th day before the rash.

⇓

After about 7 days of viremia, the rashes develop,

First on the face and then spreading to the neck, trunk

and extremities sparing palms & soles.

CLINICAL FEATURES OF GERMAN MEASLES

⇒ The incubation period of Rubella virus is 9-11 days.

⇒ The common symptoms include –

• Rashes
• Fever
• Lymphadenopathy
• Arthritis

⇒ The disease occurs principally in children but may affect all ages.

⇒ Rubella can be of two types – Congenital or Post-Natal Rubella.

⇒ If rubella occurs in early pregnancy, the fetus may die. Transient effects observed in infants with Congenital Rubella infection includes –

• Cardiac defects
• Cataract
• Deafness
• Hepatosplenomegaly
• Thrombocytopenic purpura
• Myocarditis
• Bone lesions
• Mental retardation

⇒ In neonates and Adults, infection occurs through the mucosa of the upper Respiratory tract and termed as post-natal rubella infection.

⇒ The symptom of postnatal rubella begins with Malaise followed by fever, lymphadenopathy, and Rashes; arthritis is more common in females.

LABORATORY DIAGNOSIS OF RUBELLA VIRUS

⇒ In Pregnancy: Diagnosis can be done by virus isolation or serology. The virus can be isolated from blood during the early stage in RK or Vero cells. Virus-specific IgG and IgM antibodies can be detected by ELISA.

⇒ In congenital rubella: Virus can be isolated from urine, leucocytes, bone marrow or CSF. Viral-specific IgM antibodies can be detected in newborns.

PROPHYLAXIS OF GERMAN MEASLES

⇒ Live attenuated vaccine for rubella is available and can be administered subcutaneously.

⇒ A combined mumps-measles-rubella (MMR) vaccine is recommended for the infants at the age of 5 months, followed by a booster at the age of 4-6 years.

SAHIL BATRA

Hi, I’m the Founder and Developer of Paramedics World, a blog truly devoted to Paramedics. I am a Medical Lab Tech, a Web Developer and Bibliophiliac. My greatest hobby is to teach and motivate other peoples to do whatever they wanna do in life.