TORCH infections

Author: Mohamed Mahrous, Medical writer, Ontario, Canada and DermNet NZ Editor-in-Chief: A/Prof Amanda Oakley, Dermatologist, Hamilton, New Zealand. February 2018. 

TORCH infections

Upper respiratory tract infections are common in pregnancy and are generally no more serious than when not pregnant. However, the infections listed here are important causes of maternal and fetal morbidity and mortality. The risk that the infection will harm the fetus is often greater if infected in early pregnancy.

Refer also to listeriosis, a cause of fetal loss.

The acronym TORCH has been used as a reminder of infections that cause congenital defects. The TORCH complex represents:

"Others" represent syphilis (a bacterial infection), parvovirus B19 (B19V, cause of fifth disease), varicella-zoster virus (VZV, cause of chickenpox), measles virus, enteroviruseslymphocytic choriomeningitis virus, human immunodeficiency virus (HIV), and zika virus.  Other viruses suspected of causing intrauterine infection are West Nile virus, adenovirus and hepatitis E virus. 


  • Toxoplasmosis is a protozoan parasite infecting many mammals and birds.
  • Infection is unnoticed in most people but in 10% if can cause swollen lymph nodes or chorioretinitis (inflammation of the eye).
  • Infection is transmitted from undercooked meat or is due to poor kitchen hygiene. Cat faeces are a common source.
  • Primary infection during pregnancy can lead to fetal loss or congenital toxoplasmosis and affects about 1 in 1000 newborn babies in the USA.
  • Congenital toxoplasmosis can result in chorioretinitis with blindness and anaemia, hepatic or neurological symptoms.


  • Syphilis is a sexually transmitted spirochaete bacterial infection.
  • Primary chancre is followed by a secondary rash and mucosal lesions. Latent infection can be followed by tertiary, gummatous syphilis.
  • Early maternal infection after 16 weeks gestation can cause fetal loss or congenital syphilis. 
  • Signs include blisters, scaly rash, mucous patches and condyloma latum. Infected infants are very infectious.
  • Other signs are snuffles, inflamed bones, swollen liver and lymph glands; anaemia, thrombocytopenia and leukocytosis.
  • Late congenital syphilis often affects eyes (interstitial keratitis), ears, joints and central nervous system.
  • Characteristic signs include Hutchinson teeth, typical facial appearance and bowed sabre shins.
  • Syphilis is cured by antibiotics including penicillin, but some signs of congenital syphilis are permanent.

TORCH viral infections

The TORCH viruses are listed alphabetically below.

"TORCH" viral infections

Cytomegalovirus (CMV)

  • Primary CMV infection is asymptomatic or causes fever, fatigue, and enlarged lymph nodes.  
  • Primary, reactivation, or recurrent CMV infection can occur in pregnancy.
  • Transplacental transmission of CMV in 0.5–1.5% of pregnancies can result in intrauterine growth restriction, sensorineural hearing loss, intracranial calcification, microcephaly, hydrocephalus, hepatosplenomegaly, delayed psychomotor development, optic atrophy and fetal death.
  • Infection is more severe in the first trimester and more common in the third trimester.  
  • Ganciclovir stops the progression of hearing loss in affected infants and may reverse it. 

Ebola virus

  • Most cases of Ebola virus have occurred in West Africa.
  • Ebola causes rapid onset of fever, myalgia, weakness, fatigue and gastroenteritis. It has a high mortality.
  • There is some suggestion that pregnant women may be more susceptible to severe disease and death from Ebola.
  • There is currently no specific treatment for Ebola infection.
  • Prompt isolation and infection control measures are critical. 
  • Treatment consists of supportive care, including hydration and correction of electrolytic disturbance and coagulopathy.

Enterovirus infections

  • Enteroviruses are the cause of hand foot and mouth disease.
  • It is not clear if enterovirus infections cross the placenta.
  • Some studies have linked coxsackievirus and echovirus to miscarriage, and fetal neurodevelopmental delay, myocarditis, and cortical necrosis.   

Herpes simplex (HSV)

  • HSV is the cause of herpes simplex (cold sores) and genital herpes.
  • Intrauterine HSV infection is associated with fetal intrauterine growth restriction, preterm labour, and miscarriage.  
  • Both HSV-1 and HSV-2 may cause neonatal herpes infection in 1-in-1,700 to 1-in-12,500 births). Neonatal herpes infection is defined as infection within 28 days of birth. HSV-2 is more common than HSV-1.
  • Ninety percent of neonatal infections are perinatally transmitted in the birth canal. Dissemination can result in blisters on skin, eyes, or mouth; one-third develop meningitis or encephalitis, and multiple organs are infected in one quarter.  
  • Aciclovir has been shown to prevent recurrences of HSV lesions during pregnancy and is indicated for the treatment of neonatal HSV.  

Human immunodeficiency virus (HIV)

  • HIV is the cause of AIDS. 
  • Congenital HIV infection is a major cause of infant and childhood morbidity and mortality, responsible for an estimated 4 million deaths since the start of the HIV pandemic.   
  • Infection can be transmitted from an infected mother during pregnancy, during delivery or subsequently through breast milk. The infected mother should be treated with antiretroviral treatment. Breast feeding is discouraged to reduce transmission.
  • Symptoms can include weight loss, lack of energy, fevers, enlarged lymph nodes, and serious bacterial, fungal and viral infections.

Influenza virus

  • Influenza is a cause of a febrile illness with cough, rhinitis, headache, sore throat, myalgia, and shortness of breath.
  • Pregnant women are more likely than non-pregnant individuals to develop complications of influenza virus, such as decreased lung capacity, increased oxygen needs, and increased heart rate.
  • Inactivated influenza vaccine is recommended in all trimesters of pregnancy and reduces the risk of infection and its severity.  

Lymphocytic choriomeningitis virus (LCM)

  • LCM virus causes a non-specific illness with fever, myalgias and headache for 2–3 weeks.
  • The main hosts for LCM virus are rodents. 
  • LCM virus is associated with sporadic cases of congenital infection.
  • Affected infants present with chorioretinitis, hydrocephalus, mental retardation, and/or visual impairment. 


  • Measles causes a febrile respiratory illness in children with characteristic rash.
  • During pregnancy, measles tends to be severe with pneumonitis predominating
  • Maternal infection is associated with spontaneous abortion, premature labour, and low birth weight. 

Parvovirus B19

  • Parvovirus B19 is the cause of erythema infectiosum and papular purpuric gloves and socks syndrome.
  • Infection during pregnancy occurs in 1–5% of pregnancies. The virus can cause miscarriage, fetal anaemia, hydrops fetalis, myocarditis, and/or intrauterine fetal death.
  • Infection occurs most frequently in the winter and spring. 
  • Hydrops fetalis due to B19 infection is treated by intrauterine blood transfusions. 
  • Treatment is limited to symptomatic relief of mothers with acetaminophen/paracetamol and to the treatment of fetal anaemia.


  • Rubella is the cause of a febrile illness with lymphadenopathy and a rash.
  • Congenital rubella syndrome (CRS) is characterised by intrauterine growth restriction, intracranial calcifications, microcephaly, cataracts, cardiac defects, neurological disease, osteitis, and hepatosplenomegaly.
  • Blueberry muffin appearance is due to extramedullary haematopoeisis.
  • Most of these complications develop in infants born to mothers who acquire rubella infection during the first 16 weeks of pregnancy, when 50–80% of exposed fetuses are infected.  

Varicella-zoster virus (VZV)

  • VZV is the cause of chickenpox, a childhood illness characterised by an itchy vesicular eruption and later recurrence in some people as shingles.
  • VZV affects about 1 in 10,000 pregnancies. Morbidity and mortality rates associated with VZV infection are much higher in pregnant adults than in children, mostly due to pneumonitis. VZV is especially dangerous in the third trimester of pregnancy.
  • Congenital varicella syndrome results in spontaneous abortion, fetal chorioretinitis, cataracts, limb atrophy, cerebral cortical atrophy, and/or neurological disability.  
  • Aciclovir is indicated for the treatment of varicella pneumonia during pregnancy but has not been studied in uncomplicated chickenpox in immunocompetent pregnant women.

Zika virus

  • Zika virus is transmitted by mosquitos, mainly in tropical regions.
  • It causes a febrile illness with conjunctivitis, myalgia and a rash.
  • Zika causes severe congenital abnormalities, including microcephaly.  
  • Positional, hearing and ocular abnormalities have also been reportedly due to congenital infection.

Prevention of infection in pregnancy

It is very important to educate women of child-bearing age about the importance of vaccination against measles, rubella and varicella-zoster virus.  

Pregnant women should take care to avoid contact with persons with viral infections and to wash hands frequently when handling food, animals, and children. If exposure to TORCH infections does occur, the patient should seek immediate medical assistance.  Pregnant women should be warned about the risks of travel to regions in which relevant infections are endemic.


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