The causal agent of Toxoplasmosis is the bacteria Toxoplasma gondii. a member of the phylum Apicomplexa which includes other parasites responsible for a variety of diseases (malaria, cryptosporidiosis).
Toxoplasma Tachyzoites (Image: CDC USA)
Page Links: Introduction | Some Recent Findings | Toxoplasma Lifecycle | Genome | References | WWW Links | Glossary
"Bacteria and protists are rarely teratogenic, but two of them can damage human embryos. Toxoplasma gondii, a protozoan carried by rabbits and cats (and their feces), can cross the placenta and cause brain and eye defects in the fetus. Treponema pallidum, the cause of syphilis, can kill early fetuses and produce congenital deafness in older ones."
(Text extract from: Developmental Biology. 6th ed. Gilbert, Scott F. Sunderland (MA): Sinauer Associates, Inc.; c2000. Toxoplasma gondii)
Acute infections in pregnant women can be transmitted to the fetus and cause severe illness (e.g., mental retardation, blindness, and epilepsy). An estimated 400-4,000 cases of congenital toxoplasmosis occur each year in the United States. Of the 750 deaths attributed to toxoplasmosis each year, 375 (50%) are believed to be caused by eating contaminated meat, making toxoplasmosis the third leading cause of foodborne deaths in this country. (From CDC Puiblication - Preventing Congenital Toxoplasmosis)
Reviews | Articles | Search NCBI Bookshelf | Search PubMed
Reviews
Hill DE, Chirukandoth S, Dubey JP. Biology and epidemiology of Toxoplasma gondii in man and animals. Anim Health Res Rev. 2005 Jun;6(1):41-61.
Saeij JP, Boyle JP, Boothroyd JC Differences among the three major strains of Toxoplasma gondii and their specific interactions with the infected host. Trends Parasitol. 2005 Oct;21(10):476-81.
Articles
Gatkowska J, Hiszczynska-Sawicka E, Kur J, Holec L, Dlugonska H. Toxoplasma gondii: An evaluation of diagnostic value of recombinant antigens in a murine model. Exp Parasitol. 2006 May 15
Sensini A. Toxoplasma gondii infection in pregnancy: opportunities and pitfalls of serological diagnosis. Clin Microbiol Infect. 2006 Jun;12(6):504-12.
Gruenberg J, van der Goot FG. Toxoplasma: guess who's coming to dinner. Cell. 2006 Apr 21;125(2):226-8.
Search NCBI Bookshelf: Bookshelf - Toxoplasma gondii
Medical Microbiology - Toxoplasma gondii | Molecular Biology of the Cell - The life cycle of the intracellular parasite Toxoplasma gondii | Molecular Biology of the Cell - Pathogens in many forms
Search PubMed: Search May 2006 "Toxoplasma gondii" 8,909 reference articles of which 656 were reviews. Search term = Toxoplasma gondii
CDC Publications (USA) Toxoplasmosis Factsheet | Toxoplasma gondii Infection in the United States, 1999–2000 | Newborn Screening for Congenital Infectious Diseases | Preventing Congenital Toxoplasmosis |
Australia
World Health Organisation (WHO) Toxoplasmosis among women with habitual abortion
Toxoplasma Full-Length cDNA project (WHO) Toxoplasma
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Below is a list of some known maternal (then fetal) infections that impact upon neurological development.
Only a very brief overview is given, for more details see Abnormal Development Notes or the listed internal and external links.
Viral infection causes systemic infection and extensive brain damage and cell death by necrosis.
NCBI Bookshelf (external link) Medical Microbiology: Cytomegalovirus | Search Medical Microbiology "Cytomegalovirus"
Viral infection causes systemic infection and extensive brain damage and cell death by necrosis.
NCBI Bookshelf (external link) Search Medical Microbiology "Herpes Simplex Virus"
Bacterial infection by E. coli or streptocci B. can cause vascular thrombosis involving choroid plexus which can effect CSF flow, and can cause hydrocephalus.
NCBI Bookshelf (external link) Search Medical Microbiology "Purulent Meningitus"
Toxoplasma infection causes random necrosis throughout the brain and can cause hydrocephalus.
NCBI Bookshelf (external link) Medical Microbiology: 84. Toxoplasma Gondii | Figure 84-1. Girl with hydrocephalus due to congenital toxoplasmosis. | Search Medical Microbiology "Toxoplasmosis"
The Australian NHMRC (1988) recommends neonates be assessed for follow-up care under the following conditions.
(see the NHMRC WWW Page)
These developmental abnormalities usually involve only small DNA mutations affecting individual or a few genes, two exceptions are the major chromosomal abnormalities usualy trisomy; trisomy 21 (Down syndrome) and trisomy 18 (Edwards syndrome) (also trisomy 9, 13, 15). Note that the occurance of chromosomal abnormalities also increases with increasing maternal age. There are many pamphlets providing information about prenatal diagnosis (see NSW State Health Publication Checking your baby's health before birth).
Each section of the notes covering early development and specific systems contain references to specific abnormalities (on Page 2 of each notes section). The best source for Australian statistical data is the Australian Institute of Health and Welfare National Perinatal Statistics Unit, UNSW which publishes "Congenital Malformations Australia" every 2 years. Be aware that some congenital abnormalities, by their nature, affect multiple systems. In the USA, the Center for Disease Control (CDC) keeps and publishes relevant statistical information. A very difficult issue in abnormal development are the many different Ethical implications.
This current page is a link to Normal and Abnormal Development and Population Data.
You should look at normal development. Development Notes
Alternatively, go on to look at Systematic Development of organs and tissues.
For those wanting to see dynamic processes of development (and have a reasonably quick connection) then the Movies pages are good for watching changes occur.
The study of human development has relied extensively on studying the process in other model animals. For those wanting to see the process of development in other species then the other embryos pages are a good start.
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Abnormalities in human development can be due to many different maternal factors, this page gives introduces Toxoplasmosis infection and links to several external resources for further information.
Please email Dr Mark Hill if you wish to make a comment about this current project.
