TORCH infections

TORCH infections

Upper respiratory tract infections are common in pregnancy and are generally no more serious than when the mother is 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 the mother is 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:

• Toxoplasmosis
• Others
• Rubella
• Cytomegalovirus (CMV)
• Herpes (simplex) virus (HSV).

The 'Others' category includes represent syphilis, a bacterial infection; parvovirus B19 (B19V, cause of fifth disease); the cause of erythema infectiosum (also known as fifth disease); varicella zoster virus (VZV) cause of chickenpox measles virus enteroviruses; lymphocytic choriomeningitis (LCM) 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

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

Syphilis

• Syphilis is a sexually transmitted bacterial infection caused by Spirochaeta bacteria.
• Primary chancre (lesion) is followed by a secondary rash and mucosal lesions. Latent infection can be followed by tertiary, gummatous (tumourous) syphilis.
• Early maternal infection can cause fetal loss or congenital syphilis.
• The signs of syphilis include blisters, scaly rash, mucous patches and condyloma latum. Infected infants are very infectious.
• Other signs are snuffles, inflamed bones, a swollen liver and swollen lymph glands, anaemia, thrombocytopenia, and leukocytosis.
• Late congenital syphilis often affects the eyes, resulting in interstitial keratitis (inflammation of the cornea), ears, joints, and central nervous system.
• Characteristic signs of congenital syphilis include Hutchinson teeth, bowed sabre shins (malformation of the tibia, with bowing or convexity) and the typical facial appearance (a prominent brow ridge, a 'saddle nose' with a collapse in the bony part of the nose, a short upper jaw, a defect in the hard palate, and protruding jaw).
• Syphilis is cured by antibiotics, including penicillin, but some signs of congenital syphilis are permanent.

TORCH viral infections

The TORCH viral infections are listed alphabetically below.

Measles 

Parvovirus 

Varicella 

Cytomegalovirus

• Primary CMV infection is either asymptomatic or causes fever, fatigue, and enlarged lymph nodes.
• Primary, reactivated, or recurrent CMV infection can occur in pregnancy.
• The transplacental transmission of CMV occurs in 0.5–1.5% of pregnancies and can result in intrauterine growth restriction, sensorineural hearing loss, intracranial calcification, microcephaly, hydrocephalus, hepatosplenomegaly, delayed psychomotor development, optic atrophy, and fetal death.
• CMV 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 (a type of acute kidney failure).

Herpes simplex virus

• 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 type 1 HSV (HSV-1) and type 2 HSV (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 of the infection this way can result in blisters on skin, eyes, or mouth; one third develop meningitis or encephalitis, and multiple organs are infected in one quarter of cases.
• 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 is the cause of AIDS (acquired immunodeficiency syndrome).
• Congenital HIV infection is a major cause of infant and childhood morbidity and mortality, and is 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 HIV-infected mother should be treated with antiretroviral treatment. Breast feeding is discouraged to reduce HIV 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 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.
• Infants affected with LCM virus present with chorioretinitis, hydrocephalus, intellectual disability, and/or visual impairment.

Measles

• Measles causes a febrile respiratory illness in children with a 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

• B19V is the cause of erythema infectiosum and papular purpuric gloves and socks syndrome.
• Infection with B19V during pregnancy occurs in 1–5% of pregnancies. The virus can cause miscarriage, fetal anaemia, hydrops fetalis (abnormal accumulation of fluid in the fetal tissues), myocarditis, and/or intrauterine fetal death.
• Infection occurs most frequently in the winter and spring.
• Hydrops fetalis due to B19V infection is treated by intrauterine blood transfusions.
• Treatment is limited to symptomatic relief of mothers with paracetamol (acetaminophen) and to the treatment of fetal anaemia.

Rubella

• Rubellacauses febrile illness with lymphadenopathy and a rash.
• Congenital rubella syndrome is characterised by intrauterine growth restriction, intracranial calcifications, microcephaly, cataracts, cardiac defects, neurological disease, osteitis (inflammation of the bones), and hepatosplenomegaly.
• A 'blueberry muffin' appearance is due to extramedullary haematopoeisis (maturation of blood cells that occurs outside of the bone marrow).
• Most of these complications develop in infants born to mothers who acquire rubella infection during the first 16 weeks of pregnancy, which is when 50–80% of exposed fetuses are infected.

Varicella zoster virus

• VZV is the cause of chickenpox, a childhood illness characterised by an itchy vesicular eruption, that later reoccurs in some people as shingles (herpes zoster).
• VZV affects about 1 in 10,000 pregnancies. The morbidity and mortality rates associated with VZV infection are much higher in pregnant women 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 its effects have not been studied in uncomplicated chickenpox in immunocompetent pregnant women.

Zika virus

• Zika virus is transmitted by mosquitoes, 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 all been reported as resulting from congenital infection.

Prevention of infection in pregnancy

It is very important to educate women of childbearing age about the importance of vaccination against measles, rubella, and VZV.

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 also be warned about the risks of travel to regions where these infections are endemic.