TORCH infections can be transmitted to a newborn during a variety of stages. During pregnancy, the mother can transmit the infection to the fetus through the placenta, the organ that provides oxygen and nutrients from the mother to the developing fetus. During childbirth, the infant may catch the infection from the mother while passing through the birth canal. After birth, the mother can pass an infection to the infant through breast milk. The mothers initially become infected through a variety of different means that depend on the specific type of infection.
Toxoplasma gondii is a protozoan parasite that is primarily transmitted through consumption of undercooked meats or exposure to cat feces. It can result in toxoplasmosis, which may present as fever and fatigue in the mother. If passed to a fetus or infant, toxoplasmosis may cause inflammation of the choroid and retina in the eye (i.e., chorioretinitis), a buildup of fluid in the brain (i.e., hydrocephalus), rash, and intracranial calcifications.
In the case of rubella, a mother may become infected if they are exposed to the rubella virus through direct contact with infected saliva, mucus, or air droplets. In the mother, rubella may present with mild symptoms: swollen lymph nodes (i.e., lymphadenopathy), polyarthritis, or rashes. However, rubella that is transmitted to a developing fetus during pregnancy can result in congenital rubella syndrome, which is characterized by deafness, clouding of the eyes (i.e., cataracts), rash, and heart defects.
Like rubella, cytomegalovirus (CMV) can be transmitted through direct contact with infected bodily fluids, including saliva, tears, mucus, semen, and vaginal fluids. Although symptoms of CMV are generally mild for adults, a congenital CMV infection in a developing fetus can present with rashes, deafness, inflammation of the eye (i.e., chorioretinitis), seizures, an unusually small head (i.e., microcephaly), and intracranial calcifications.
The herpes simplex virus (HSV) is very contagious, and the two types of the virus can be transmitted in two ways. HSV-1, also called oral herpes, can be transmitted through the exchange of oral secretions (e.g., kissing, sharing utensils, sharing drinks, etc.), while HSV-2 is a sexually transmitted disease. HSV usually infects a newborn during passage through the birth canal. In infants, HSV can cause blisters and inflammation of the brain, known as meningoencephalitis.
Other agents that can cause TORCH infections include
Treponema pallidum,
varicella zoster virus (VZV),
parvovirus B19, and
human immunodeficiency virus (
HIV).
Treponema pallidum is the bacterium that causes
syphilis. When transmitted to the fetus during pregnancy, the resulting
congenital syphilis can lead to fetal death. If the fetus survives, congenital syphilis may cause craniofacial malformations, rash, and deafness.
Treponema pallidum can also pass from mother to infant during
vaginal delivery. VZV, the virus responsible for
chickenpox, can cause congenital
varicella syndrome in a developing fetus. Meanwhile, severe reduction in red blood cells is a symptom of parvovirus B19, which can lead to anemia in an infected newborn. The majority of
HIV infections in young children occur during delivery or
breastfeeding. Newborns with HIV may present with low birth weight and hepatosplenomegaly, and they may develop recurrent bacterial infections, such as
meningitis and
pneumonia. In addition to these agents,
Zika virus, which is carried by mosquitoes, is a recent addition to the list of infectious diseases that can cause a congenital infection.