Below is a list of some known maternal, then fetal and postnatal infections that impact upon development. Only a very brief overview is given for each virus for more specific details see the listed internal and external links. Viruses cannot reproduce by themselves and therefore infect cells to use the cell machinery to produce more virus. Different viruses have genetic material as single- or double-stranded RNA or DNA. The infectious virus particle is called a "virion" and is the genetic material packed in a protein shell. Viruses come in many genetic sizes, as little as 4 proteins up to 200 proteins. |
Viral infections can range in their effects from no discernable impact through to severe impacts on development. Furthermore this may occur either directly by the infection or indirectly by the associated maternal fever and other side-effects of the infection. (More? Maternal Hyperthermia)
Rubella virus "German Measles" infection during pregnancy is one of the most serious causing congenital rubella syndrome with serious malformations of the developing fetus. (More? Rubella)
Viral infections have also recently been in the news with the 2009 novel influenza A (H1N1) "Swine Flu" pandemic. (More? Swine Influenza Virus)
Some early postnatal viral infections can also impact upon development and have been the target for worldwide immunization and eradication. (More? Polio)
Human Immunodeficiency Virus (HIV) leads to AIDS and according to United Nations 2005 data about 38.6 million people had HIV. Of the 17.3 million women infected with HIV, 3.28 million gave birth each year (mostly in sub-Saharan Africa), leading to 700,000 new infections of HIV in children each year. (More? Human Immunodeficiency Virus)
Note also that many cancers can be caused by viruses (papilloma viruses, hepatitis B and C viruses, Epstein-Barr virus and human T-cell lymphotropic virus). Virus-induced cancers account for about 20% of worldwide cancer incidence.
In a few developing countries, and mainly in Africa, at least 3 viruses induce a hemorrhagic fever: Ebola hemorrhagic fever, Marburg virus disease, and Lassa fever.
Page Links: Introduction | Some Recent Findings | Rubella Images | Cytomegalovirus | Herpes Simplex Virus | Hepatitis Virus | Human Immunodeficiency Virus | Influenza Virus | Swine Influenza Virus | Avian Influenza Virus | Lassa Virus | Adenovirus | Prevention | References | WWW Links | Glossary
Related Pages: Herpes Simplex Virus | Rubella | Lassa virus | Polio |
Dating the emergence of pandemic influenza viruses. Smith GJ, Bahl J, Vijaykrishna D, Zhang J, Poon LL, Chen H, Webster RG, Peiris JS, Guan Y. Proc Natl Acad Sci U S A. 2009 Jul 13. PMID: 19597152
"In the 20th century, 3 influenza viruses caused major pandemics: the 1918 H1N1 virus, the 1957 H2N2 virus, and the 1968 H3N2 virus. These pandemics were initiated by the introduction and successful adaptation of a novel hemagglutinin subtype to humans from an animal source, resulting in antigenic shift. ...Our results indicate that genetic components of the 1918 H1N1 pandemic virus circulated in mammalian hosts, i.e., swine and humans, as early as 1911 and was not likely to be a recently introduced avian virus. Phylogenetic relationships suggest that the A/Brevig Mission/1/1918 virus (BM/1918) was generated by reassortment between mammalian viruses and a previously circulating human strain, either in swine or, possibly, in humans. Furthermore, seasonal and classic swine H1N1 viruses were not derived directly from BM/1918, but their precursors co-circulated during the pandemic. Mean estimates of the time of most recent common ancestor also suggest that the H2N2 and H3N2 pandemic strains may have been generated through reassortment events in unknown mammalian hosts and involved multiple avian viruses preceding pandemic recognition. The possible generation of pandemic strains through a series of reassortment events in mammals over a period of years before pandemic recognition suggests that appropriate surveillance strategies for detection of precursor viruses may abort future pandemics."
Cytomegalovirus infection in the human placenta: maternal immunity and developmentally regulated receptors on trophoblasts converge. Pereira L, Maidji E. Curr Top Microbiol Immunol. 2008;325:383-95. Review. PMID: 19067401
"During human pregnancy, CMV infects the uterine-placental interface with varied outcomes from fetal intrauterine growth restriction to permanent birth defects, depending on the level of maternal immunity and gestational age. Virus spreads from infected uterine blood vessels, amplifies by replicating in decidual cells, and disseminates to the placenta in immune complexes."
(More? UNSW Embryology - Rubella)
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Viral infection causes systemic infection and extensive brain damage and cell death by necrosis.
References: Cytomegalovirus infection in the human placenta: maternal immunity and developmentally regulated receptors on trophoblasts converge. Pereira L, Maidji E. Curr Top Microbiol Immunol. 2008;325:383-95. Review. PMID: 19067401 |
Links: Medical Microbiology- Cytomegalovirus | Search Medical Microbiology "Cytomegalovirus"
NCBI Bookshelf (external link) Search Medical Microbiology "Herpes Simplex Virus"
Search PubMed: term = Herpes Simplex Virus teratology | embryo infection | fetal infection | neonatal infection
Poliomyelitis (polio) is a highly infectious viral disease, affecting only humans of any age, but mainly children under the age of 3 (> 50% cases) causing paralysis and death. There are three types (type 1, type 2, and type 3) of wild poliovirus which can invade the nervous system and can cause total paralysis in several hours.
(More? UNSW Embryology - Polio)
Pubmed Coll O, Suy A, Hernandez S, Pisa S, Lonca M, Thorne C, Borrell A. Prenatal diagnosis in human immunodeficiency virus-infected women: a new screening program for chromosomal anomalies. Am J Obstet Gynecol. 2006 Jan;194(1):192-8.
Search PubMed: term = Human Immunodeficiency Virus teratology | embryo infection | fetal infection | neonatal infection
Links: British HIV Association Guidelines for management of HIV and hepatitis C coinfection in adults |
Guidelines for the management of HIV infection in pregnant women and the prevention of mother-to-child transmission of HIV, 2005 |
Guidelines for management of HIV and hepatitis B coinfection in adults |
World Health Organization HIV-infected women and their families: psychosocial support and related issues. A literature review. 2003
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Hepatitis (inflammation of the liver) is caused in humans by one of 7 viruses (A, B, C, D, E) with the 2 additional F has not been confirmed as a distinct genotype; and G is a newly described flavivirus. "All of these viruses can cause an acute disease with symptoms lasting several weeks including yellowing of the skin and eyes (jaundice); dark urine; extreme fatigue; nausea; vomiting and abdominal pain. It can take several months to a year to feel fit again." (CDC text). Virus particles measure 42nm in overall diameter and contain a 27nm diameter DNA-based core. |
Hepatitis Transmission Risk to the Fetus
Hepatitis A
Hepatitis B
Hepatitis C
Data Source: Hepatitis and reproduction. Practice Committee of American Society for Reproductive Medicine. Fertil Steril. 2008 Nov;90(5 Suppl):S226-35. Review. PMID: 19007636
References:
Search PubMed: term = Hepatitis Virus teratology | embryo infection | fetal infection | neonatal infection
Flu is the general term and abbreviation of influenzaviral infections and the possible teratogenic effect of influenza viruses (orthomyxoviruses, "flu") is unclear, with very little evidence directly linking the two events. A relatively recent study was unable to identify any placental transmission of influenza virus during the second and third trimester. Severe maternal infection though may lead to hyperthermia, which has been demonstrated to be teratogenic, particularly in early neural development. (More? Maternal Hyperthermia)
Irving WL, James DK, Stephenson T, Laing P, Jameson C, Oxford JS, Chakraverty P, Brown DW, Boon AC, Zambon MC. Influenza virus infection in the second and third trimesters of pregnancy: a clinical and seroepidemiological study. BJOG. 2000 Oct;107(10):1282-9.
"We found no evidence for transplacental transmission of influenza virus or auto-antibody production in pregnancies complicated by influenza infections. There was an increase in the complications of pregnancy in our influenza cohort."
Postnatally, the suggested initial limited neonatal immune system makes postnatal infection dangerous.
References:
Brankston G, Gitterman L, Hirji Z, Lemieux C, Gardam M. Transmission of influenza A in human beings. Lancet Infect Dis. 2007 Apr;7(4):257-65.
Links: Medline Plus - Flu | Search Medical Microbiology "orthomyxovirus"
In 2009 a global pandemic of the novel influenza A (H1N1) or Swine Flu has occurred. At this stage the possible teratogenic effect of this influenza virus should be considered the same as those described for the influenza virus above. The term "Pandemic" refers only to the spread of the virus, not the severity of the infection or potential developmental outcomes. This virus has also been spreading in an unseasonable pattern, that is in the northern hemisphere summer, when typically viral infections increase in the winter period.
H1 refers to one of the hemagglutinin subtypes (H1, H2 or H3) and N1 refers to one of the two neuraminidase subtypes (N1 or N2). Over the last century there have been at least three different human viral pandemic circulating strains H1N1 (1918, 1977), H2N2 (1957) and H3N2 (1968).
Region |
Number of Confirmed Cases |
Number of Confirmed Deaths |
USA |
37,246 |
211 |
Mexico |
11,699 |
121 |
Canada |
9,717 |
39 |
UK |
9,718 |
14 |
Europe |
13,667 |
16 |
(Table data source: BMJ 2009;339:b2840)
Confirmed infections per million population (July 2009)
Australia - H1N1 Influenza 09 (Human Swin Flu) Facts
Australian State Information
(Facts from: Australian Commonwealth Department of Health and Ageing H1N1 Influenza 09 (Human Swine influenza) – Summary Sheet for General Practitioners Current as of 24 May 2009)
UK Information
20 July 2009: Chief Medical Officer's advice to pregnant women
"Some pregnant women who catch the H1N1 (swine) ‘flu virus will develop complications of the infection (including pneumonia) that could put their own and their baby’s health at risk. The risks are greatest in the second and third trimesters of pregnancy. It is too early in the pandemic of influenza to be able to quantify these risks for the individual but most pregnant women who catch the disease are likely to make an uncomplicated recovery...."
Links: WHO - H1N1 Pandemic | USA CDC - H1N1 Flu | Medline Plus - H1N1 Flu (Swine Flu) | GenBank sequences from pandemic (H1N1) 2009 viruses
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In 1997 the first instance of direct bird-to-human spread of influenza A (H5N1) virus was documented during an outbreak of avian influenza among poultry in Hong Kong. The virus caused severe respiratory illness in 18 people (6 died) and there have been subsequent instances of other H5N1 infection. The virus does not typically infect humans, and there is no evidence yet of a direct effect on development. |
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Lassa virus of the arenaviridae family, a single-stranded RNA virus. The virus is the causative agent of a hemorrhagic fever and can be transmitted between species (zoonotic). Death rates are high for women in the third trimester of pregnancy. Fetal death (95%) occurs in uterus of infected pregnant mothers. (More? UNSW Embryology - Lassa virus) |
Adenoviruses have a double-stranded linear DNA structure. This virus family is the causative agent of membrane infections in: respiratory tract, eyes, gastrointestinal tract, and urinary tract.
Modified adenovirus is currently used as a research tool to introduce genes into cells in vitro and in animal systems.
Links: Medical Microbiology - Adenoviruses | Search Medical Microbiology "adenovirus"
References:
Gordon JW. Adenovirus gene transfer vector toxicity to mouse embryos: implications for human IVF. Hum Reprod. 2002 Sep;17(9):2380-7.
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Coxsackie B virus are 6 pathogenic enteroviruses with a range of adult illness from mild gastrointestinal to pericarditis and myocarditis. These viruses may cause an increase in early spontaneous abortions and rarely a fetal myocarditis. |
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Marburg RNA virus of the filovirus family, causes hemorrhagic fever in both humans and non-human primates and is a very rare. Virus has characteristic "Shepherd’s Crook" shape. |
The Australian NHMRC (1988) recommends neonates be assessed for follow-up care under the following conditions.
CDC (USA)
Public Health Training Network Epidemiology and Prevention of Vaccine-Preventable Diseases (viewable Webcasts requires Media Player) |
Advisory Committee on Immunization Practices (ACIP) Recommendations
Royal College of Obstetricians and Gynaecologists (UK)
Infection and Pregnancy - study group recommendations (Jun 2001)
Reviews | Articles | Search NCBI Bookshelf | Search PubMed | Glossary
Cytomegalovirus infection in the human placenta: maternal immunity and developmentally regulated receptors on trophoblasts converge. Pereira L, Maidji E. Curr Top Microbiol Immunol. 2008;325:383-95. Review. PMID: 19067401
Degani S. Sonographic findings in fetal viral infections: a systematic review. Obstet Gynecol Surv. 2006 May;61(5):329-36.
Ornoy A, Tenenbaum A. Pregnancy outcome following infections by coxsackie, echo, measles, mumps, hepatitis, polio and encephalitis viruses. Reprod Toxicol. 2006 May;21(4):446-57.
Giles ML, Garland SM, Grover SR, Lewin SM, Hellard ME. Impact of an education campaign on management in pregnancy of women infected with a blood-borne virus. Med J Aust. 2006 Apr 17;184(8):389-92.
Kriebs JM. Changing the paradigm: HIV in pregnancy. J Perinat Neonatal Nurs. 2006 Jan-Mar;20(1):71-3.
Bailao LA, Osborne NG, Rizzi MC, Bonilla-Musoles F, Duarte G, Bailao TC. Ultrasound markers of fetal infection part 1: viral infections. Ultrasound Q. 2005 Dec;21(4):295-308.
Slowik MK, Jhaveri R. Hepatitis B and C viruses in infants and young children. Semin Pediatr Infect Dis. 2005 Oct;16(4):296-305.
Dating the emergence of pandemic influenza viruses. Smith GJ, Bahl J, Vijaykrishna D, Zhang J, Poon LL, Chen H, Webster RG, Peiris JS, Guan Y. Proc Natl Acad Sci U S A. 2009 Jul 13. PMID: 19597152
Revello MG, Zavattoni M, Furione M, Fabbri E, Gerna G. Preconceptional primary human cytomegalovirus infection and risk of congenital infection. J Infect Dis. 2006 Mar 15;193(6):783-7.
Coll O, Suy A, Hernandez S, Pisa S, Lonca M, Thorne C, Borrell A. Prenatal diagnosis in human immunodeficiency virus-infected women: a new screening program for chromosomal anomalies. Am J Obstet Gynecol. 2006 Jan;194(1):192-8.
Search NCBI Bookshelf: prenatal viral infection | Medical Microbiology - prenatal viral infection
Search PubMed: Search May 2006 "prenatal viral infection" 2,710 reference articles of which 441 were reviews.
Search term = prenatal viral infection | rubella virus | Cytomegalovirus | Herpes Simplex Virus | Polio |
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You should look at normal development of the effected systems in the embryo. Development Notes
Alternatively, go on to look at Systematic Development of organs and tissues.
This quick link is to the abnormal development page for each system. |