Vertically transmitted infection

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Vertically transmitted infection
CMV placentitis1 mini.jpg
Micrograph of cytomegalovirus (CMV) infection of the placenta (CMV placentitis), a vertically transmitted infection: The characteristic large nucleus of a CMV-infected cell is seen off-centre at the bottom-right of the image, H&E stain.
Specialty Pediatrics   Blue pencil.svg

A vertically transmitted infection is an infection caused by pathogens (such as bacteria and viruses) that uses mother-to-child transmission, that is, transmission directly from the mother to an embryo, fetus, or baby during pregnancy or childbirth. It can occur when the mother gets an infection as an intercurrent disease in pregnancy. Nutritional deficiencies may exacerbate the risks of perinatal infection.

Infection invasion of a host by disease-causing organisms

Infection is the invasion of an organism's body tissues by disease-causing agents, their multiplication, and the reaction of host tissues to the infectious agents and the toxins they produce. Infectious disease, also known as transmissible disease or communicable disease, is illness resulting from an infection.

In biology, a pathogen, in the oldest and broadest sense, is anything that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ.

Bacteria A domain of prokaryotes – single celled organisms without a nucleus

Bacteria are a type of biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods and spirals. Bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep portions of Earth's crust. Bacteria also live in symbiotic and parasitic relationships with plants and animals. Most bacteria have not been characterised, and only about half of the bacterial phyla have species that can be grown in the laboratory. The study of bacteria is known as bacteriology, a branch of microbiology.

Contents

Examples

Bacteria, viruses, and other organisms are able to be passed from mother to child. Several vertically transmitted infections are included in the TORCH complex, which stands for:

  1. T Toxoplasmosis / Toxoplasma gondii
  2. O Other infections (see below)
  3. R Rubella
  4. C Cytomegalovirus
  5. H Herpes simplex virus-2 or neonatal herpes simplex

"Other infections" include:

Parvovirus B19 species of virus

Primate erythroparvovirus 1, generally referred to as B19 virus, parvovirus B19 or sometimes erythrovirus B19, was the first known human virus in the family Parvoviridae, genus Erythroparvovirus; it measures only 23–26 nm in diameter. The name is derived from Latin, parvum meaning small, reflecting the fact that B19 ranks among the smallest DNA viruses. B19 virus is most known for causing disease in the pediatric population; however, it can also affect adults. It is the classic cause of the childhood rash called fifth disease or erythema infectiosum, or "slapped cheek syndrome".

Coxsackievirus A virus that causes digestive upset and sometimes heart damage

Coxsackievirus is a virus that belongs to a family of nonenveloped, linear, positive-sense single-stranded RNA viruses, Picornaviridae and the genus Enterovirus, which also includes poliovirus and echovirus. Enteroviruses are among the most common and important human pathogens, and ordinarily its members are transmitted by the fecal-oral route. Coxsackieviruses share many characteristics with poliovirus. With control of poliovirus infections in much of the world, more attention has been focused on understanding the nonpolio enteroviruses such as coxsackievirus.

Chickenpox Human viral disease

Chickenpox, also known as varicella, is a highly contagious disease caused by the initial infection with varicella zoster virus (VZV). The disease results in a characteristic skin rash that forms small, itchy blisters, which eventually scab over. It usually starts on the chest, back, and face then spreads to the rest of the body. Other symptoms may include fever, tiredness, and headaches. Symptoms usually last five to seven days. Complications may occasionally include pneumonia, inflammation of the brain, and bacterial skin infections. The disease is often more severe in adults than in children. Symptoms begin 10 to 21 days after exposure to the virus.

The human T-lymphotropic virus, human T-cell lymphotropic virus, or human T-cell leukemia-lymphoma virus (HTLV) family of viruses are a group of human retroviruses that are known to cause a type of cancer called adult T-cell leukemia/lymphoma and a demyelinating disease called HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP). The HTLVs belong to a larger group of primate T-lymphotropic viruses (PTLVs). Members of this family that infect humans are called HTLVs, and the ones that infect Old World monkeys are called Simian T-lymphotropic viruses (STLVs). To date, four types of HTLVs and four types of STLVs have been identified. HTLV types HTLV-1 and HTLV-2 viruses are the first retroviruses which were discovered. Both belong to the oncovirus subfamily of retroviruses and can transform human lymphocytes so that they are self-sustaining in vitro. The HTLVs are believed to originate from intraspecies transmission of STLVs. The HTLV-1 genome is diploid, composed of two copies of a single-stranded RNA virus whose genome is copied into a double-stranded DNA form that integrates into the host cell genome, at which point the virus is referred to as a provirus. A closely related virus is bovine leukemia virus BLV. The original name for HIV, the virus that causes AIDS, was HTLV-3. Confusingly, however, since reassignment, the virus now called HTLV-3 is not HIV.

Syphilis sexually transmitted infection

Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum subspecies pallidum. The signs and symptoms of syphilis vary depending in which of the four stages it presents. The primary stage classically presents with a single chancre but there may be multiple sores. In secondary syphilis, a diffuse rash occurs, which frequently involves the palms of the hands and soles of the feet. There may also be sores in the mouth or vagina. In latent syphilis, which can last for years, there are few or no symptoms. In tertiary syphilis, there are gummas, neurological problems, or heart symptoms. Syphilis has been known as "the great imitator" as it may cause symptoms similar to many other diseases.

Zika fever infectious arboviral disease

Zika fever, also known as Zika virus disease or simply Zika, is an infectious disease caused by the Zika virus. Most cases have no symptoms, but when present they are usually mild and can resemble dengue fever. Symptoms may include fever, red eyes, joint pain, headache, and a maculopapular rash. Symptoms generally last less than seven days. It has not caused any reported deaths during the initial infection. Mother-to-child transmission during pregnancy can cause microcephaly and other brain malformations in some babies. Infections in adults have been linked to Guillain–Barré syndrome (GBS).

Hepatitis B may also be classified as a vertically transmitted infection. The virus is large and does not cross the placenta. Hence it cannot infect the fetus unless breaks in the maternal-fetal barrier have occurred. But such breaks can occur in bleeding during childbirth or amniocentesis. [7]

Hepatitis B human viral infection

Hepatitis B is an infectious disease caused by the hepatitis B virus (HBV) that affects the liver. It can cause both acute and chronic infections. Many people have no symptoms during the initial infection. Some develop a rapid onset of sickness with vomiting, yellowish skin, tiredness, dark urine and abdominal pain. Often these symptoms last a few weeks and rarely does the initial infection result in death. It may take 30 to 180 days for symptoms to begin. In those who get infected around the time of birth 90% develop chronic hepatitis B while less than 10% of those infected after the age of five do. Most of those with chronic disease have no symptoms; however, cirrhosis and liver cancer may eventually develop. These complications result in the death of 15 to 25% of those with chronic disease.

<i>Hepatitis B virus</i> species of the genus Orthohepadnavirus

Hepatitis B virus, abbreviated HBV, is a partially double-stranded DNA virus, a species of the genus Orthohepadnavirus and a member of the Hepadnaviridae family of viruses. This virus causes the disease hepatitis B.

Childbirth expulsion of a fetus from the pregnant mothers uterus

Childbirth, also known as labour and delivery, is the ending of a pregnancy by one or more babies leaving a woman's uterus by vaginal passage or Caesarean section. In 2015, there were about 135 million births globally. About 15 million were born before 37 weeks of gestation, while between 3 and 12% were born after 42 weeks. In the developed world most deliveries occur in hospitals, while in the developing world most births take place at home with the support of a traditional birth attendant.

The TORCH complex was originally considered to consist of the four conditions mentioned above, [8] with the "TO" referring to Toxoplasma. The four-term form is still used in many modern references, [9] and the capitalization "ToRCH" is sometimes used in these contexts. [10] The acronym has also been listed as TORCHES, for TOxoplasmosis, Rubella, Cytomegalovirus, HErpes simplex, and Syphilis.

A further expansion of this acronym, CHEAPTORCHES, was proposed by Ford-Jones and Kellner in 1995: [11]

Signs and symptoms

The signs and symptoms of a vertically transmitted infection depend on the individual pathogen. In the mother it may cause subtle signs such as an influenza-like illness, or possibly no symptoms at all. In such cases the effects may be seen first at birth.

Symptoms of a vertically transmitted infection may include fever and flu like symptoms. The newborn is often small for gestational age. A petechial rash on the skin may be present, with small reddish or purplish spots due to bleeding from capillaries under the skin. An enlarged liver and spleen (hepatosplenomegaly) is common, as is jaundice. However, jaundice is less common in hepatitis B because a newborn's immune system is not developed well enough to mount a response against liver cells, as would normally be the cause of jaundice in an older child or adult. Hearing impairment, eye problems, mental retardation, autism, and death can be caused by vertically transmitted infections.

The genetic conditions of Aicardi-Goutieres syndrome are possibly present in a similar manner. [13] [14]

Routes

The main routes of transmission of vertically transmitted infections are across the placenta (transplacental) and across the female reproductive tract during childbirth.

Transmission is also possible by breaks in the maternal-fetal barrier such by amniocentesis [7] or major trauma.

Transplacental

The embryo and fetus have little or no immune function. They depend on the immune function of their mother. Several pathogens can cross the placenta and cause (perinatal) infection. Often, microorganisms that produce minor illness in the mother are very dangerous for the developing embryo or fetus. This can result in spontaneous abortion or major developmental disorders. For many infections, the baby is more at risk at particular stages of pregnancy. Problems related to perinatal infection are not always directly noticeable.

During childbirth

Babies can also become infected by their mothers during birth. Some infectious agents may be transmitted to the embryo or fetus in the uterus, while passing through the birth canal, or even shortly after birth. The distinction is important because when transmission is primarily during or after birth, medical intervention can help prevent infections in the infant.

During birth, babies are exposed to maternal blood, body fluids, and to the maternal genital tract without the placental barrier intervening. Because of this, blood-borne microorganisms (hepatitis B, HIV), organisms associated with sexually transmitted disease (e.g., Neisseria gonorrhoeae and Chlamydia trachomatis ), and normal fauna of the genitourinary tract (e.g., Candida albicans ) are among those commonly seen in infection of newborns.

Pathophysiology

Virulence versus symbiosis

In the spectrum of optimal virulence, vertical transmission tends to evolve benign symbiosis. It is, therefore, a critical concept for evolutionary medicine. Because a pathogen's ability to pass from parent to child depends significantly on the hosts' ability to reproduce, pathogens' transmissibility tends to be inversely related with their virulence. In other words, as pathogens become more harmful to, and thus decrease the reproduction rate of, their host organism, they are less likely to be passed on to the hosts' offspring, since they will have fewer offspring. [15]

Although HIV is sometimes transmitted through perinatal transmission, its virulence can be accounted for because its primary mode of transmission is not vertical. Moreover, medicine has further decreased the frequency of vertical transmission of HIV. The incidence of perinatal HIV cases in the United States has declined as a result of the implementation of recommendations on HIV counselling and voluntary testing practices and the use of zidovudine therapy by providers to reduce perinatal HIV transmission. [16]

The price paid in the evolution of symbiosis is, however, great: for many generations, almost all cases of vertical transmission will continue to be pathological—in particular if any other routes of transmission exist. Many generations of random mutation and selection are needed to evolve symbiosis. During this time, the vast majority of vertical transmission cases exhibit the initial virulence.[ citation needed ]

In dual inheritance theory, vertical transmission refers to the passing of cultural traits from parents to children. [17]

Diagnosis

When physical examination of the newborn shows signs of a vertically transmitted infection, the examiner may test blood, urine, and spinal fluid for evidence of the infections listed above. Diagnosis can be confirmed by culture of one of the specific pathogens or by increased levels of IgM against the pathogen.[ citation needed ]

Classification

A vertically transmitted infection can be called a perinatal infection if it is transmitted in the perinatal period, which is the period starting at a gestational age of between 22 [18] and 28 weeks [19] (with regional variations in the definition) and ending seven completed days after birth. [18]

The term congenital infection can be used if the vertically transmitted infection persists after childbirth.

Treatment and prevention

Micrograph of a pap test showing changes (upper-right of image) associated with herpes simplex virus, a vertically transmitted infection Herpes simplex virus pap test.jpg
Micrograph of a pap test showing changes (upper-right of image) associated with herpes simplex virus, a vertically transmitted infection

Some vertically transmitted infections, such as toxoplasmosis and syphilis, can be effectively treated with antibiotics if the mother is diagnosed early in her pregnancy. Many viral vertically transmitted infections have no effective treatment, but some, notably rubella and varicella-zoster, can be prevented by vaccinating the mother prior to pregnancy.

Pregnant women living in malaria endemic areas are candidates for malaria prophylaxis. It clinically improves the anemia and parasitemia of the pregnant women, and birthweight in their infants. [20]

If the mother has active herpes simplex (as may be suggested by a pap test), delivery by Caesarean section can prevent the newborn from contact, and consequent infection, with this virus.

IgG2 antibody may play crucial role in prevention of intrauterine infections and extensive research is going on for developing IgG2-based therapies for treatment and vaccination. [21]

Prognosis

Each type of vertically transmitted infection has a different prognosis. The stage of the pregnancy at the time of infection also can change the effect on the newborn.

See also

Related Research Articles

Toxoplasmosis parasitic human disease

Toxoplasmosis is a parasitic disease caused by Toxoplasma gondii. Infections with toxoplasmosis usually cause no obvious symptoms in adults. Occasionally, people may have a few weeks or months of mild, flu-like illness such as muscle aches and tender lymph nodes. In a small number of people, eye problems may develop. In those with a weak immune system, severe symptoms such as seizures and poor coordination may occur. If infected during pregnancy, a condition known as congenital toxoplasmosis may affect the child.

Virulence is a pathogen's or microbe's ability to infect or damage a host.

Coinfection is the simultaneous infection of a host by multiple pathogen species. In virology, coinfection includes simultaneous infection of a single cell by two or more virus particles. An example is the coinfection of liver cells with hepatitis B virus and hepatitis D virus, which can arise incrementally by initial infection followed by superinfection.

In medicine, public health, and biology, transmission is the passing of a pathogen causing communicable disease from an infected host individual or group to a particular individual or group, regardless of whether the other individual was previously infected.

ICD-10 is an international statistical classification used in health care and related industries.

Herpes simplex virus Species of virus

Herpes simplex virus1 and 2, also known by their taxonomical names Human alphaherpesvirus 1 and Human alphaherpesvirus 2, are two members of the human Herpesviridae family, a set of viruses that produce viral infections in the majority of humans. Both HSV-1 and HSV-2 are very common and contagious. They can be spread when an infected person begins shedding the virus. About 67% of the world population under the age of 50 has HSV-1. In the United States more than one-in-six people have HSV-2. Although it can be transmitted through any intimate contact, it is one of the most common sexually transmitted infections.


TORCH syndrome is a cluster of symptoms caused by congenital infection with toxoplasmosis, rubella, cytomegalovirus, herpes simplex, and other organisms including syphilis, parvovirus, and Varicella zoster. Zika virus is considered the most recent member of TORCH infections.

Maternal health is the health of women during pregnancy, childbirth, and the postpartum period. It encompasses the health care dimensions of family planning, preconception, prenatal, and postnatal care in order to ensure a positive and fulfilling experience in most cases and reduce maternal morbidity and mortality in other cases.

Condom effectiveness is how effective condoms are at preventing STDs and pregnancy. Correctly using male condoms and other barriers like female condoms and dental dams, every time, can reduce the risk of sexually transmitted diseases (STDs), including human immunodeficiency virus (HIV) and viral hepatitis. They can also provide protection against other diseases that may be transmitted through sex like Zika and Ebola. Using male and female condoms correctly, every time, can also help prevent pregnancy.

The Central Nervous System controls most of the functions of the body and mind. It comprises the brain, spinal cord and the nerve fibers that branch off to all parts of the body. The Central Nervous System viral diseases are caused by viruses that attack the CNS. Existing and emerging viral CNS infections are major sources of human morbidity and mortality. Virus infections usually begin in the peripheral tissues, and can invade the mammalian system by spreading into the peripheral nervous system and more rarely the CNS. CNS is protected by effective immune responses and multi-layer barriers, but some viruses enter with high-efficiency through the bloodstream and some by directly infecting the nerves that innervate the tissues. Most viruses that enter can be opportunistic and accidental pathogens, but some like herpes viruses and rabies virus have evolved in time to enter the nervous system efficiently, by exploiting the neuronal cell biology. While acute viral diseases come on quickly, chronic viral conditions have long incubation periods inside the body. Their symptoms develop slowly and follow a progressive, fatal course.

Sexually transmitted infection Infection transmitted through human sexual behavior

Sexually transmitted infections (STI), also referred to as sexually transmitted diseases (STD), are infections that are commonly spread by sexual activity, especially vaginal intercourse, anal sex and oral sex. Many times STIs initially do not cause symptoms. This results in a greater risk of passing the disease on to others. Symptoms and signs of disease may include vaginal discharge, penile discharge, ulcers on or around the genitals, and pelvic pain. STIs can be transmitted to an infant before or during childbirth and may result in poor outcomes for the baby. Some STIs may cause problems with the ability to get pregnant.

Herpes simplex Viral disease caused by the herpes simplex virus

Herpes simplex is a viral infection caused by the herpes simplex virus. Infections are categorized based on the part of the body infected. Oral herpes involves the face or mouth. It may result in small blisters in groups often called cold sores or fever blisters or may just cause a sore throat. Genital herpes, often simply known as herpes, may have minimal symptoms or form blisters that break open and result in small ulcers. These typically heal over two to four weeks. Tingling or shooting pains may occur before the blisters appear. Herpes cycles between periods of active disease followed by periods without symptoms. The first episode is often more severe and may be associated with fever, muscle pains, swollen lymph nodes and headaches. Over time, episodes of active disease decrease in frequency and severity. Other disorders caused by herpes simplex include: herpetic whitlow when it involves the fingers, herpes of the eye, herpes infection of the brain, and neonatal herpes when it affects a newborn, among others.

Neonatal herpes simplex is a rare but serious condition, usually caused by vertical transmission of herpes simplex virus from mother to newborn. Around 1 in every 3,500 babies in the United States contract the infection.

Congenital cytomegalovirus infection mother-to-child transmission of cytomegalovirus occurring in the prenatal period

Congenital cytomegalovirus infection refers to a condition where cytomegalovirus is transmitted in the prenatal period.

An intercurrentdisease in pregnancy is a disease that is not directly caused by the pregnancy, but which may become worse or be a potential risk to the pregnancy. A major component of this risk can result from necessary use of drugs in pregnancy to manage the disease.

In pregnancy, there is an increased susceptibility and/or severity of several infectious diseases.

HIV in pregnancy is the presence of HIV in a woman while she is pregnant. HIV in pregnancy is of concern because women with HIV/AIDS may transmit the infection to their child during pregnancy, childbirth and while breastfeeding. However, the risk of mother-to-child transmission of HIV may be reduced by treatment of the HIV infection with antiretroviral therapy (ART). This lifelong therapy may be initiated in women before, during, and after pregnancy. After delivery, children are also given the medication temporarily as a prophylactic measure to reduce the risk of infection. Because HIV may also be spread through breast milk, mothers in the United States who are infected are encouraged to avoid breastfeeding. However, in developing countries such as South Africa, where the risk of death of the infant associated with avoiding exclusive breastfeeding is higher than the risk of contracting HIV, exclusive breastfeeding in a mother who is virally suppressed is encouraged.

Neonatal infection human disease

Neonatal infections are infections of the neonate (newborn) acquired during prenatal development or in the first four weeks of life. Neonatal infections may be contracted by mother to child transmission, in the birth canal during childbirth, or contracted after birth. Some neonatal infections are apparent soon after delivery, while others may develop in the postnatal period. Some neonatal infections such as HIV, hepatitis B, and malaria do not become apparent until much later.

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Classification
D