出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2016/08/03 16:21:12」(JST)
Vertically transmitted infection | |
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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.
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Classification and external resources | |
Specialty | pediatrics |
ICD-10 | P35-P39 |
ICD-9-CM | 771 |
[edit on Wikidata]
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A vertically transmitted infection (or mother-to-child transmission) is an infection caused by bacteria, viruses, or in rare cases, parasites transmitted 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.
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 22 weeks[1] to 28[2] (with regional variations in the definition) and ending seven completed days after birth.[1]
The term congenital infection can be used if the vertically transmitted infection persists after childbirth.
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:
The "other agents" under O include:
Hepatitis B may also be classified as a vertically transmitted infection, but the hepatitis B virus is a large virus and does not cross the placenta, hence it cannot infect the fetus unless breaks in the maternal-fetal barrier have occurred, such as can occur in bleeding during childbirth or amniocentesis.[9]
The TORCH complex was originally considered to consist of the four conditions mentioned above,[10] with the "TO" referring to Toxoplasma. The four-term form is still used in many modern references,[11] and the capitalization "ToRCH" is sometimes used in these contexts.[12] 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:[13]
The signs and symptoms of a vertically transmitted infection depend on the individual pathogen. It may cause subtle signs such as a influenza-like illness and may not even be noticed by the mother during the pregnancy. In such cases, the effects may be seen first at birth.
Symptoms of a vertically transmitted infection may include fever and poor feeding. 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 mother often has a mild infection with few or no symptoms.
The genetic conditions of Aicardi-Goutieres syndrome are possibly present in a similar manner.[15][16]
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The main routes of transmission of vertically transmitted infections are across the placenta (transplacental) and across the female reproductive tract during childbirth.
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.
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.
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.[17]
Although AIDS 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 AIDS. The incidence of perinatal AIDS 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.[18]
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.[19]
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]
CMV placentitis
CMV placentitis
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.
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.[20]
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.
Vertically transmitted infections (P35–P39, 771)
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Gestational |
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During birth |
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Late pregnancy |
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By breastfeeding |
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Certain conditions originating in the perinatal period / fetal disease (P, 760–779)
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Maternal factors and complications of pregnancy, |
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Length of gestation and fetal growth |
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Birth trauma |
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By system |
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Infectious |
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Other |
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リンク元 | 「母子感染」「垂直感染」「vertical disease transmission」「MTCT」「mother-to-child transmission」 |
関連記事 | 「transmission」「vertical」 |
胎内感染 | 分娩時感染 | 母乳時感染 | ||||
経胎盤感染 | 上行性感染 | 経胎盤感染 | 産道感染 | 母乳感染 | ||
ウイルス | 風疹ウイルス | ○ | × | × | × | × |
サイトメガロウイルス | ○ | × | × | △ | △ | |
ヒトパルボウイルスB19 | ○ | × | × | × | × | |
水痘・帯状疱疹ウイルス | △ | × | × | ○ | × | |
単純ヘルペスウイルス | △ | △ | × | ○ | × | |
B型肝炎ウイルス | △ | × | △ | ○ | × | |
C型肝炎ウイルス | △ | × | △ | ○ | × | |
成人T細胞白血病ウイルス1型 | △ | × | × | × | ○ | |
ヒト免疫不全ウイルス | △ | △ | △ | ○ | △ | |
細菌 | 梅毒トレポネーマ | ○ | × | × | △ | × |
淋菌 | × | × | × | ○ | × | |
B群連鎖球菌 | × | × | × | ○ | × | |
真菌 | カンジダ・アルビカンス | × | × | × | ○ | × |
原虫 | トキソプラズマ | ○ | × | × | × | × |
クラミジア | クラミジア・トラコマチス | × | × | × | ○ | × |
病原体 | 疾患 | 感染経路 | 問題となる感染時期 | 母体 | 胎児 | |
ウイルス | 風疹ウイルス | 先天性風疹症候群 | 経胎盤感染 | 妊娠12週未満。18週未満は軽微 | 初感染妊婦 | |
サイトメガロウイルス | 巨細胞封入体症 | 経胎盤感染 | 妊娠前半 | 初感染妊婦。感冒様症状 | 小頭症、脳内石灰化、精神遅滞、網脈絡膜炎、感音性難聴、貧血、黄疸、出血斑、低体重児、肝脾腫 | |
ヒトパルボウイルスB19 | 経胎盤感染 | 妊娠20週未満 | 伝染性紅斑 | 非免疫性胎児水腫、胎児死亡 | ||
水痘・帯状疱疹ウイルス | 先天性水痘症候群 | 産道感染 | 妊娠20週未満 | 初感染妊婦 | 精神遅滞、網脈絡膜炎、皮膚瘢痕、四肢低形成、低出生体重児 | |
単純ヘルペスウイルス | 新生児ヘルペス | 産道感染 | ~ | 中枢神経:小頭症、眼:脈絡網膜炎、角結膜炎、皮膚:水疱疹 | ||
B型肝炎ウイルス | 産道感染 | ~ | 無症候キャリアー化 | |||
C型肝炎ウイルス | 産道感染 | ~ | ||||
成人T細胞白血病ウイルス1型 | 母乳感染 | ~ | ||||
ヒト免疫不全ウイルス | HIV感染症 | 産道感染 | ~ | HIV感染症 | HIV感染症 | |
細菌 | 梅毒トレポネーマ | 先天梅毒 | 経胎盤感染 | 妊娠14週以降 | 梅毒 | 水頭症、難聴、老人様顔貌、鼻炎、粘膜斑(梅毒性天疱瘡)、黄疸、貧血、点状出血、パロー仮性麻痺、肝脾腫、骨軟骨炎 晩発性梅毒、ハッチンソン三徴 |
淋菌 | 淋疾 | 産道感染 | ~ | 産科合併症(流産・早産、前期破水、絨毛膜羊膜炎、子宮内膜炎) | 化膿性結膜炎(膿漏眼) | |
B群連鎖球菌 | B群連鎖球菌感染症 | 産道感染 | ~ | 常在菌 | 髄膜炎 | |
真菌 | カンジダ・アルビカンス | 産道感染 | ~ | 常在菌。カンジダ膣炎 | 口腔内カンジダ症 | |
原虫 | トキソプラズマ | 先天性トキソプラズマ症 | 経胎盤感染 | 妊娠中後期 | 初感染妊婦。無症状 | 脳室拡大、小頭症、脳内石灰化、髄膜炎、精神遅滞、脳性麻痺、けいれん、網脈絡膜炎、黄疸、発疹、貧血、リンパ節腫脹、肝脾腫、低出生体重児 |
クラミジア | クラミジア・トラコマチス | 産道感染 | ~ | 無症状。早産・流産 | 新生児結膜炎、新生児肺炎 |
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