Of use to O&G and other clinicians

1. TORCH
Foreword
Infections acquired in utero or during the birth process are a significant cause of fetal
and neonatal mortality and an important contributor to early and later childhood
morbidity. The original concept of the TORCH perinatal infections was to group 5
infections with similar presentations, including rash and ocular findings.
Introduction
The TORCH test, which is sometimes called the TORCH panel is actually a category of
blood tests called Infectious-Disease Antibody Titer tests [IDAT]. TORCH tests measure
the presence of antibodies against a specific group of infectious diseases and their level
of concentration in the blood. TORCH is an acronym for a group of 5 infectious
diseases:
• Toxoplasmosis
• Other (Syphilis)
• Rubella (German measles)
• Cytomegalovirus (CMV)
• Herpes Simplex Virus (HSV)
These 5 diseases are relevant as
1. Each disease may be teratogenic;
2. Each crosses the placenta;
3. Each may adversely affect the developing foetus;
4. The effect of each varies, depending on developmental stage at time of
exposure.
All are grouped together because they can cause a cluster of symptomatic birth defects
in newborns, collectively called the TORCH syndrome. The guiding reasons to think of
TORCH infections could be:
• IUGR infants
• Hepatosplenomegaly
• Thrombocytopenia
• Unusual rash
• Bad maternal obstetric history [BOH]
• Classic findings of any specific infection
Bad obstetric history (BOH) implies previous unfavourable foetal outcome in terms of 2
or more consecutive spontaneous abortion, history of intrauterine foetal death,
intrauterine growth retardation, still births, early neonatal death and / or congenital
anomalies. Cause of BOH may be genetic, hormonal, abnormal maternal immune
response and maternal infection. Recurrent pregnancy wastage due to maternal
infections transmissible in utero at various stage of gestation can be caused by a wide
array of organisms which include the TORCH complex.
Background of TORCH diseases
Toxoplasmosis
Caused by Toxoplasma gondii, and is found in human worldwide, a
parasite that the mother can acquire from handling infected cats,
drinking unpasteurized milk, or eating contaminated meat. The
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2. infection is carried to the infant through the mother's placenta, and
can cause infections of the eyes or central nervous system. The later
in pregnancy that the mother is infected, the higher the probability
that the fetus will be infected. On the other hand, toxoplasmosis early
in pregnancy is more likely to cause a miscarriage or serious birth
defects.
Syphilis
This disease is added to the TORCH panel because of a rapid
increase in reported cases since 1990. It is also a potentially lifethreatening infection for the fetus.
Rubella
This is a virus that has a seasonal pattern, with epidemics most likely
in the spring. Between 0.1-2% of newborns will be infected with
rubella. The rate of fetal infection varies according to the timing of the
mother's infection during pregnancy. Birth defects, however, are most
likely (85%) in infants infected during the first eight weeks of
pregnancy.
Cytomegalovirus This is also a virus belonging to the herpesvirus group. It can be
(CMV)
transmitted through body secretions, as well as by sexual contact;
some newborns which acquire CMV through the mother's breast
milk. Infected infants may have severe problems, such as hearing
loss, mental retardation, pneumonia, hepatitis, or
blood disorders.
Herpes simplex This is also a virus that enters the infant through his eyes, skin,
mouth, and upper respiratory tract. About 20% of infants born with
HSV infection will have localized infections of the eyes, mouth, or
skin and about 50% of infected infants will develop disease spread
throughout the body (disseminated) within (9-11) days after birth.
HSV-2 is sexually transmitted. Symptoms include genital ulcers or
sores. In addition to oral and genital sores, the virus can also lead to
complications such as infection of the lining of the brain and the brain
itself (meningoencephalitis) or infection of the eye especially the
conjunctiva and cornea.
Mode of transmission
Toxoplasmosis
•
•
•
• Rubella
•
• Cytomegalo
•
virus
•
• Herpes virus
Syphilis
•
•
Handling of excrement of infected cats,
Drinking unpasteurized goat’s milk,
Eating contaminated meat.
Salivary secretions
Secretions from cutaneous ulcers.
Cervical secretions
Sexual contact;
Blood & its products
Time to perform
1. As a routine at the time of 1st antenatal visit;
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3. 2. Repeat Ig G (Serum) at mid trimester. (possibility of seroconversion);
3. In a suspected pregnancy case, where patients shows Flu-like symptoms & rash
while pregnant;
4. Amniotic fluid testing later.
5. Cord blood to know fetal infection.
Result interpretation
1. Serial serological testing (ELISA) is preferable and diagnosis of acute infection is
made at <12 weeks of gestation if it is +ve for IgG & IgM antibodies.
2. If IgM is -ve & IgG is +ve, repeat after 3 weeks and check for 4-fold rise.
3. If -ve in early pregnancy, perform test at 18-20 weeks of gestation.
(Joul. Of OBGI Feb-2006).
Summary
TORCH screening is now accepted by clinicians as a reliable test for investigating
pregnant women and infants for congenital, perinatal and neonatal TORCH infections.
The IgG antibody in the pregnant woman may be a sign of past infection with one of
these infectious agents. By testing a second blood sample drawn 2 weeks later, the
level of antibody can be compared. If the second blood draw shows an increase in IgG
antibody, it may indicate a recent infection with the infectious agent.
IgM is never zero as it cross-reacts with many other IgMs and other proteins. IgM is a
specific class of antibodies that seeks out virus particles. It is, therefore, the most useful
indicator of the presence of a TORCH infection. Any general abnormal or positive
presence gives high levels of IgM finding. IgM antibodies against TORCH organisms
usually persist for about 3 months, while IgG antibodies remain detectable for a lifetime,
providing immunity and preventing or reducing the severity of reinfection. Thus,
1. If IgM antibodies are present in a pregnant woman, a current or recent infection with
the organism has occurred.
2. If IgM antibodies are absent and IgG antibodies are present and do not demonstrate
an increase on serial testing several weeks later, it can be assumed that the person
has had a previous infection by the corresponding organism, or has been vaccinated
to prevent an infection.
3. If the serum of a person has no evidence of either IgM or IgG antibodies specific for
the organism, then the person is at risk of infection because they do not have any
demonstrable immunity.
Reference:
1. Indian Journal of Medical Microbiology, (2002) 20 (1): 57-58, Prevalence of torch infections in Indian
pregnant women, S Singh
2. Indian Journal of Medical Microbiology, (2003) 21 (2):108-110, seroprevalence of torch infection in
bad obstetric history, D Turbadkar, M Mathur, M Rele.
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