TOXOPLASMOSIS
Developed by
Pam Holmes, Christy Stalcup, and
Pam Yarborough
WHAT IS TOXOPLASMOSIS?
Toxoplasmosis is an infection caused by a parasite most
often found in cats and farm animals. Humans can catch
this disease from:
coming into contact with infected cat feces
eating raw or undercooked meat that’s infected
eating contaminated vegetables or fruits
being born with it
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Note: Once a person is infected, the infection remains in
the body for life, usually in an inactive form. It can
reactivate when that person’s immune system is weak.
About 98% of cases of Toxoplasmosis are
acquired through Congenital Toxoplasmosis.
One study showed that 76% of
infants infected with congenital
toxoplasmosis had ocular lesions,
51% had neurological involvement,
and 26% had either hydrocephalus
(increased intracranial pressure) or
michrocephaly (small brain). It is
evident that vision problems are
very common with Congenital
Toxoplasmosis.
Once the mother develops
immunity to the organism, all
future pregnancies are protected
from transmission of the organism.
Signs and Symptoms
1. Toxoplasmosis in an otherwise healthy person
may have no symptoms or only a few swollen
glands usually in the patient’s neck.
2. Toxoplasmosis in a person with a weakened
immune system may only have symptoms of
swollen glands, or in the case of an infection
that attacks the brain and nervous system, the
symptoms may include fever, seizures,
headache, psychosis, and problems with vision,
speech, movement, or thinking.
3. Children born with Toxoplasmosis, which accounts for
about 98% of cases, may show symptoms including:
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Fever
Swollen glands
Jaundice
An unusually large or small head
Rash
Bruises or bleeding under the skin
Anemia
Enlarged liver or spleen
Seizures
Limp muscle tone
Mental retardation
Hearing loss
Vision problems (toxoplasmosis of the eye)
Toxoplasmosis of the Eye
Congenital Toxoplasmosis is the
most common form. If the
mother acquires the infection
during the first trimester, 17%
of these babies develop
congenital toxoplasmosis and
the effects are severe.
However, if the infection
occurs during the third
trimester, 65% of the babies
develop the disease. Yet, the
infant usually has no
symptoms.
90
80
70
Develop
Toxoplas
mosis
60
50
40
Do not
develop
Toxoplas
mosis
30
20
10
0
1st 3rd
Tri. Tri.
DAMAGE TO THE EYE
The parasite usually invades the retina and the choroid tissue.
Depending upon the area and severity of the infection, visual
acuity can be unaffected to severely affected. The retina is
inflamed by the infection and sometimes when the inflammation
settles, scars are left on the retina. Symptoms include floaters
and blurred vision. If the scarring is on the central macula,
detailed vision will be affected. Approximately 35% of all
retinachoroiditis cases can be attributed to toxoplasmosis.
Active Toxoplasmosis
Inactive Toxoplasmosis Scar
Effects of Ocular Toxoplasmosis
Common Effects:
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Inflammation of retina
Blurred vision
Floaters
Nystagmus
Amblyopia
Squint
Occasional Effects:
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Cataracts
The eye can be small
Optic atrophy
Cerebral visual
impairment
Functional Implications
Functional implications vary depending on severity of
infection and/or scaring and how successful the
treatment. Those affected often describe vision as
“hazy” with floaters. Some implications are more
serious such as total blindness in one or both eyes.
Those affected early during pregnancy often suffer
other implications such as mild to severe mental
retardation, cerebral palsy, seizures and other
problems. Appropriate accommodations and
modifications should be determined by the FVE.
Treatment
Treatment will not result in the elimination of the
organism from the eye. Since new lesions can
form if the organism reactivates, especially
during adolescence, patients should be closely
monitored.
Medications:
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Spiramycin during pregnancy
Antibiotics and steroid tablets during an infection
Pyrimethamine/sulphadoxine for 6-12 months as
follow-up procedure
History
Sam
Sam is a third grader that was diagnosed with Toxoplasmosis (visual impairment),
mental retardation, and other health impairment. He suffered acute retino-choroidal
inflammation which produced dense scaring in both eyes. He has suffered
reactivations which caused adjacent scars creating satellite lesions to the macula in
the right eye. His eye report states that there is significant scar tissue stretching
from the nasal passage to the optic nerve. There is little medical information other
than eye examination reports. It was determined in ARD meeting that there was little
(if any) pre-natal care and treatment of the toxoplasmosis after birth. It is a
continuing problem to get consent signed to obtain medical records from the parents.
Environment
Sam is attending third grade in an inclusive classroom environment. He functions
about 2 ½ years below grade level. It is difficult to determine if it is visual deficits or
cognitive ability that hinders learning. Some modifications in the classroom are 36 pt
font, one step directions, peer tutoring, slant board, frequent breaks, well lit
environment, auditory instruction coupled with visual input, clear/uncluttered copies,
contrast, allow positioning for materials as needed, do not ask questions like “can
you see this” have him tell you what he sees, do not place him beyond 6-8 feet from
board, make sure he is wearing glasses at all times and watch for signs such at
fatigue and headaches.
Sources
http://www.nlm.nih.gov/medlineplus/ency/imagepages/17
186.htm
http://www.eyemdlink.com/Condition.asp?ConditionID=4
44
http://www.patient.co.uk/showdoc/40000376/
www.viscotland.org.uk
http://www.kidshealth.org/PagManager.jsp?dn=KidsHeal
th&lic=1&ps-107&cat_id=20045&art......
http://www.revoptom.com/handbook/sect5i.htm
Program in Low Vision Therapy, Region 4 Education
Service Center, McKinney, Bill, Ph.D. Executive
Director, 2004. Houston, Tx pg 25