دراسة عزل فيروس الحصبة الألمانية من الأجنة المجهضة والأطفال المصابين بتشوهات خلقية

 

الحصبة الألمانية من الأجنة المجهضة والأطفال المصابين بتشوهات خلقية

دراسة عزل فيروس الحصبة الألمانية من الأجنة المجهضة والأطفال المصابين بتشوهات خلقية

 ومن لديهم أمراض قلبية وراثية. تم استخدام اختبارات مختلفة لتحديد الاستجابة المناعية ضد فيروس الحصبة، وأظهرت النتائج وجود حالات إيجابية لأضداد IgM و IgG في العينات المختلفة. كما تمت دراسة تأثير التطعيم ضد فيروس الحصبة على النساء الحوامل. هذه الدراسة تسلط الضوء على الوضع الحالي للتطعيم ضد فيروس الحصبة والاستجابة المناعية لدى النساء والأطفال في المحافظتين المذكورتين.

Rubella (German measles) 

 The name rubella is derived from Latin, meaning “little red .It was
initially considered to be a variant of measles or scarlet fever and was
called “third disease ” (Chin, 2000). It was not until 1814 when it was
first described as a separate in the German medical literature (Peter,
1997).
Rubella virus infection acquired postnatally are usually mild, and
many infection are asymptomatic, lymphadenopathy, and low –grade
fever. Joint aches are also common, particularly in women. Rare
complications include thrombocytopenia and encephalitis (CDC &
Prevention, 2005). Humans are the only known host of the rubella virus,
which is transmitted from person to person through respiratory droplets.
The incubation period is 14–21 days, and the disease is infectious from
one week before until four days after the onset of rash (Chin , 2000 ).

History 

 Rubella was first described by two German physicians in the mid-18th
century (TICM, 1881 ; Forbes ,1969). The disease was initially thought to
be generally mild, to occur mostly in childhood, and have few
complications. In 1914, Hess postulated a viral etiology based on his
work with monkeys .Hiro and Tosaka (1938) confirmed the viral etiology
by passing the disease to children using filtered nasal washing from acute
cases .Following a widespread Australian epidemic of rubella infection in
1941 (Gregg ,1941). The occurrence of congenital cataracts among 78
infants born following maternal rubella infection in early pregnancy .
This was the first reported recognition of congenital rubella syndrome
(CRS) (CDC , 1991 – 1992) . Most of the mothers had a history of rubella

in early pregnancy and illness with rash occurring over a limited time
period during an extensive epidemic in New South Wales. The major
historical developments in the understanding of rubella, including
isolation of virus, vaccine development, and WHO’s recommendations
for prevention of congenital rubella syndrome (McAlister, 1941 ; Weller
& Neva, 1962 ; PHSAC ,1969; Bantavala & Brown, 2004).
Rubella virus was first isolated in 1962 by Parkman and Weller.
Rubella virus is classified as Togavirus ,genus Rubivirus It is most
closely related to group A arbovirus ,such as Eastern and western Equine
Encephalitis viruses .It is an enveloped RNA virus , With a single
antigenic type that dose not cross- react with other members of the
Togavirus group (Ploikin & Orenstein, 1999).

 Physicochemical and physical properties

 Molecular mass (Mr) of virion 52 x 106. Buoyant density 1.18-1.19
g/ml in sucrose, or 1.22 g/ml in cesium chloride. Sedimentation
coefficient 280 S. growth at 37°C in culture medium). Under in vitro
conditions virions are stable. Virions sensitive to organic solvents and
detergents (which solubilzes their lipoprotein envelops). Infectivity
reduced after exposure to irradiation ( Danovaro-Holliday et al., 2003).

 Resistance to environmental conditions

 The rubella virus is relatively unstable and quite sensitive to
inactivation after 39 minutes at 56 C, 4 minutes at 70 C and 1 minute at
100C, . It dreads rapidly with conventional freezing and dried, the virus is
stable indefinitely at – 60 C and be more stabilized with protein. It can be
repeatedly frozen and have no loss of titer (FHC , 2003).
lipid solvents, weak acid and alkalis, amantadine inactivate the rubella
virus. It is also susceptible to many detergents including 1% sodium
hypochlorite, 70% ethanol and formaldehyde which soluble their
lipoprotein envelops ( Poltkin, 1999) . 

 Congenital rubella syndrome 

 Rubella virus in multiplication strategy is similar to the alphaviruses
Sindbis virus and Semliki Forest virus (SFV), which are also members of
the family Togaviridae and have been studied more intensively. While,
postnatally acquired rubella usually presents as only a mild syndrome
(with joint involvement being the most common complication), a fetus
infected via its pregnant mother can sustain birth defects (collectively
termed congenital rubella syndrome or CRS). The majority of CRS cases
involve the CNS (Atkins et al., 1995 ). It has been shown that one of the
initial steps in RV-induced teratogenesis involves the interaction of the

RV replicase (NSP90) with the retinoblastoma tumor suppressor protein
(pRb), which possibly alters fetal cell growth (Atreya et al., 1998 ).