Toxoplasmosis

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Toxoplasmosis

Toxoplasma gondii, a small parasite less than the size of a human cell, causes the
disease toxoplasmosis. T. gondii infects approximately one-third to one-half of all people
worldwide. People can acquire the parasite when they eat meat that is not cooked to well
done. They can also acquire the parasite directly or indirectly from a domestic cat (or another
member of the cat family, such as a bobcat). An acutely infected cat excretes millions of T
gondii in a dormant form called an oocyst. Even one of these oocysts can cause infection, and
can remain infectious in water for up to six months or in warm, moist soil for up to a year. An
oocyst may remain on anything that touches it. For example, it may be transferred from a cat
to garden soil, to a vegetable in the garden, and finally to someone who eats the vegetable. It
is not uncommon for someone to become infected by T. gondii without knowing the source of
the infection
If a mother is infected for the first time while she is pregnant and passes the parasite
to her child, the baby can suffer eye or brain damage. Babies infected with T. gondii while in
the womb are said to have congenital toxoplasmosis. Older children and adults who become
infected may not have symptoms, or they may develop a flu-like illness or enlarged lymph
glands. In rare cases, older children and adults who are infected develop other conditions
such as brain or heart inflammation.
T. gondii can live in the body in dormant form and can cause toxoplasmosis if a
person becomes immune compromised from conditions such as cancer, autoimmune diseases,
AIDS, or transplantation and associated treatments. It also can resurface and cause eye
disease in congenitally infected children later in life and in some older children and adults
who were infected after birth.
Treatment can prevent transmission of the parasite from mother to child. When
diagnosed and treated early, treatment can also prevent the infection's adverse effects for a
baby or for older persons with brain or eye disease. Medicines currently used to treat
toxoplasmosis have side effects. No medicines currently available can eliminate the dormant
parasites from the body, so toxoplasmosis may recur. However, there is promise for both
improved medicines and a vaccine. A chronically infected mother's immune response (if she
is not immune compromised) prevents her from transmitting the parasite to her baby.
Researchers are encouraged by this response, and are seeking a vaccine that will elicit a
similar protective immune response to prevent infection. There is also encouraging progress
being made towards discovery of improved medicines.
There are several general sanitation and food safety steps you can take to reduce your
chances of becoming infected with Toxoplasma:
-

Do not eat raw or undercooked meat. Meat should be cooked to a temperature of at
least 160°F for 20 minutes.
Do not drink unpasteurized milk.
Do not eat unwashed fruits and vegetables.
Wash hands and food preparation surfaces with warm soapy water after handling raw
meat.

-

Wear gloves when gardening. Wash hands after gardening.
Wash hands before eating (especially for children).
Keep children's sandboxes covered.
Do not drink water from the environment unless it is boiled.
Do not feed raw meat or undercooked meat to cats. Also, do not give them
unpasteurized milk.
Do not allow cats to hunt or roam.
Do not allow cats to use a garden or children's play area as their litter box.
Remove feces from the litter box daily and clean with boiling or scalding water.
Pregnant women, and persons with suppressed immune systems, should not clean the
litter box.
Control rodent populations and other potential intermediate hosts.

Congenital Anomaly

Newborn congenital anomalies, often referred to as birth defects, have a variety of
causes ranging from pregnancy or birth complications to genetic malformations to viral
infections in utero. In many cases, however, a congenital anomaly may have no known cause.
When a congenital anomaly is discovered, a complete physical examination is
important to discover and rule out multiple malformations. A detailed examination should
include:
-

Head, neck and facial features
Skin
Chest wall, heart and lungs
Abdomen
Genitalia and anus
Spine and back
Extremities (including hands and feet)
Neurological functions and reflexes

In the human embryo, the eyes are formed by a delicate and complex process.
Problems in this process can lead to congenital (present at birth) eye malformations. These
conditions are relatively rare, occurring in approximately five per 10,000 live births.
Problems in this developmental process can lead to congenital eye malformations, such as
anophthalmia (no eye), microphthalmia (small eye), coloboma (failure of the optic fissure to
close), aniridia (absent or partial iris), and optic nerve hypoplasia (underdeveloped optic
nerve).
Children’s Hospital takes full advantage of a multi-disciplinary team approach. A
team of experts may include diagnostic screenings and psychiatric support in addition to
surgical treatments and referrals to pediatric general surgeons, plastic surgeons and
orthopaedic surgeons among others.

Immunity

The immune system protects the body from possibly harmful substances by
recognizing and responding to antigens. Antigens are substances (usually proteins) on the
surface of cells, viruses, fungi, or bacteria. Nonliving substances such as toxins, chemicals,
drugs, and foreign particles (such as a splinter) can also be antigens. The system is
remarkably effective, most of the time
Immunity is the defense system with which you were born. It protects you against all
antigens. Innate immunity involves barriers that keep harmful materials from entering your
body. These barriers form the first line of defense in the immune response. Examples of
innate immunity include:
-

Cough reflex
Enzymes in tears and skin oils
Mucus, which traps bacteria and small particles
Skin
Stomach acid

Acquired immunity is immunity that develops with exposure to various antigens. Your
immune system builds a defense against that specific antigen. Infants have passive immunity
because they are born with antibodies that are transferred through the placenta from their
mother. These antibodies disappear between ages 6 and 12 months. Passive immunization
may also be due to injection of antiserum, which contains antibodies that are formed by
another person or animal. It provides immediate protection against an antigen, but does not
provide long-lasting protection. Immune serum globulin (given for hepatitis exposure) and
tetanus antitoxin are examples of passive immunization.
Vaccination (immunization) is a way to trigger the immune response. Small doses of
an antigen, such as dead or weakened live viruses, are given to activate immune system
"memory" (activated B cells and sensitized T cells). Memory allows your body to react
quickly and efficiently to future exposures.
An efficient immune response protects against many diseases and disorders. An
inefficient immune response allows diseases to develop. Too much, too little, or the wrong
immune response causes immune system disorders. An overactive immune response can lead
to the development of "autoimmune diseases," in which antibodies form against the body's
own tissues.
Complications from altered immune responses include:
-

Allergy or hypersensitivity
Anaphylaxis
Autoimmune disorders
Graft versus host disease
Immunodeficiency disorders
Serum sickness

-

Transplant rejection

References

McLoed, Rima. Tanpa tahun. “About Toxoplasmosis”. 7 Oktober 2014.
http://www.uchospitals.edu/specialties/infectious-diseases/toxoplasmosis/about.html.
Anonim. Tanpa tahun. “Newborn Congenital Anomalies”. 7 Oktober 2014.
http://www.chp.edu/CHP/newborn+congenital+anomalies.
Avery, Robert & Mohamad Jaafar. Tanpa tahun. “Congenital/Developmental Anomalies
Affecting the Eye and Orbit”. 7 Oktober 2014. http://childrensnational.org/choosechildrens/conditions-and-treatments/eye-conditions/congenital-developmental-anomaliesaffecting-the-eye-and-orbit?sc_lang=en.
Anonim. 2001. “Immune System”. 7 Oktober 2014.
http://uhaweb.hartford.edu/bugl/immune.htm.
Anonim. Tanpa tahun. “Immune Response”. 7 Oktober 2014.
http://umm.edu/health/medical/ency/articles/immune-response.

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