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Toxoplasmosis
Definition:
A common infection with the protozoan intracellular parasite Toxoplasma gondii.
Causes, incidence, and risk factors:
Toxoplasmosis is found in humans worldwide and in many species of animals and birds. The cat is the definitive
host of the parasite. Human infection results from ingestion of contaminated soil, careless handling of cat litter,
ingestion of raw or undercooked meat, or transmission from a mother to a fetus through the placenta (congenital
infection). Over 80% of primary infections produce no symptoms, but the incubation period for symptoms is 1 to
2 weeks.
Symptoms:
In the normal host:
mild febrile illness resembling mononucleosis
enlarged lymph nodes in the head and neck
headache
sore throat
muscle pain
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Rubella
Definition:
A contagious viral infection with mild symptoms associated with a rash.
Causes, incidence, and risk factors:
The disease is caused by a virus that is spread through the air or by close contact. It can also be transmitted
to a fetus by a mother with an active infection. The disease is usually mild and may even go unnoticed. Children
may have few symptoms, but adults may experience a prodrome (warning symptom) of a fever, headache, malaise, runny
nose, and inflamed eyes that lasts from 1 to 5 days before the rash appears. A person can transmit the disease
from 1 week before the onset of the rash until 1 week after the rash disappears. The disease is not as contagious
as rubeola (measles), therefore many people are not infected during childhood. Lifelong immunity to the disease
follows infection. Epidemics may occur at about 6- to 9-year intervals. The risk factors are the unimmunized individuals.
Only 1,400 cases were reported in the U.S. in 1991.
Symptoms:
low-grade fever (102 F or lower)
headache
general discomfort or uneasiness (malaise)
runny nose
inflammation of the eyes (bloodshot eyes)
rash with skin redness or inflammation
cloudy cornea
Note: There may be no symptoms
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Cytomegalovirus
Definition:
An acute viral infection causing high temperature, sore throat, and swollen lymph glands,
especially in the neck (when caused by the cytomegalovirus).
Causes, incidence, and risk factors:
The infection is caused by two viruses, the Epstein-Barr virus (EB) or cytomegalovirus (CMV pneumonia), both members
of the herpes virus family. Infection with CMV occurs less commonly than Epstein-Barr. The infection is probably
transmitted by saliva, sexual contact, respiratory droplets, and blood transfusions. Sore throat is less common
in CMV infectious mononucleosis than in Epstein-Barr. While the peak incidence occurs in 15- to 17-year-old adolescents,
the infection may occur at any age, usually between 10 and 35 years old. Abnormal lymphocytes (white blood cells)
are seen in the peripheral blood and may persist for 2 to 8 weeks. Abnormalities of liver function are also characteristic.
Risk factors other than age are not known. The incidence is 8 out of 100,000 people.
Symptoms:
fever
sore throat
enlarged lymph nodes, especially in the neck (CMV)
malaise (vague ill feeling)
frequent tiredness or fatigue
loss of appetite
muscular aches or stiffness
enlarged spleen
rash
Less frequently occurring symptoms include:
jaundice (yellow cast to skin)
headache
neck stiffness
sensitivity to light
cough
shortness of breath
chest pain
rapid heart rate
irregular heart rate
hives
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Herpes simplex.
Definition:
An infection caused by the herpes virus; it is characterized by an eruption of small and usually painful blisters
on the skin.
Causes, incidence, and risk factors:
There are two strains of herpes viruses. Herpes simplex virus type 1 (HSV-1) is usually associated with infections
of the lips, mouth, and face. It is common in children between 1 and 3 years old and may cause lesions inside the
mouth and inflamed gums. It causes cold sores or fever blisters and is transmitted by oral and respiratory secretions
(for example, sneezing or coughing can transmit the virus). Herpes simplex virus 2 (HSV-2) is usually associated
with genital lesions and is transmitted by sexual contact. Cross-infection of type 1 and 2 viruses may occur from
oral-genital sex. Both viruses are contagious and the first symptoms usually appear 1 or 2 weeks after contact
with an infected person.
The virus spreads to nerve cells within the body, and then to other mucosal skin surfaces. The virus remains dormant
in the body after an active infection and recurrences of the symptoms can take place at a later time. Recurrences
may be precipitated by overexposure to sunlight, fever, stress, or certain foods and drugs.
Symptoms:
skin rash or lesion with itching
skin rash or lesion with a burning or tingling sensation before other symptoms develop
mouth sores
genital lesions (male)
genital lesions (female)
blisters anywhere on the skin, most frequent on the mouth, lips, conjunctiva and cornea of the
eye, and the genitalia
smaller blisters merge to form a larger blister
yellow crusts form on blisters at the beginning of healing (7 to 10 days)
fever blisters
mild fever
enlargement of lymph nodes in the neck or groin
Additional symptoms that may be associated with this disease:
vaginal discharge
throat, sore
memory loss
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