Case Study
MICR 420 Emerging and Re-Emerging Infectious
Diseases
S2010
Case 10
Jessica Cisneros
Susana Hernandez
Case Summary
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3 yr old male
Acute illness with four day history of fever, fever was reduced with Tylenol
Patient experiencing fatigue
Patient had irritated, itchy eyes (bilateral conjunctivitis)
No rash
Dry cracked lips, reduction of urinary output (dehydration)
Attended preschool two times a week where he was in close contact with
multiple sick children
• During patients physical examination, the vital signs were 38.6°C and heart
beat was 126 beats/min. Respiratory rate was at 28/min.
• 100% oxygen saturation
• Nasopharyngeal swab pending
Key Information Pointing to Diagnosis
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Fever
Bilateral conjunctivitis, exudate in the left eye
Rhinorrhea
Cracked bleeding lips
Swollen lymph nodes
No rash
Feet were slightly edematous
The Diagnosis for Case 10
• Seasonal Influenza H3N2
• Presumably a laboratory test
would show the presence of H3N2
antigens
Microbiology of H3N2
• It is a from the family Orthomyxoviridae from the Genus
influenza virus, type A.
• Does not grow on plates (agar, nutrient plates)
• Single Strand (-) RNA
• Segmented in 8 parts
Pathogenesis of Seasonal H3N2
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Can be aerosol transmitted
H3N2 takes an incubation period of about three days
Has ability to bind to host cell in upper respiratory tract
Ciliated epithelial cells lost due to host and viral actions such as viral
multiplication, oxygen radical from host cell, and apoptosis
Primary Research Article Contributing to the
Understanding of this Disease
• Joshi A.Y., et al, 2009, Effectiveness of inactivated influenza vaccine in children less
than 5 years of age over multiple influenza seasons: A case–control study, Vaccine,
27:4457-4461.
• Only children from the ages of 6 to 59 months who reside in Olmsted County, MN were
allowed in the study, to guarantee a precise ascertainment of their immunization history.
▫ The study period occurred from November 1 to April 30 every year from 1999-2007.
▫ Test run polymerase chain reaction (PCR) and viral cultures
▫ The case and controls were coded as 34 children completely vaccinated with 2 doses
of Trivalent Inactivated Influenza Vaccine (TIV), 23 children partially vaccinated with 1
dose of TIV and 46 children unvaccinated
• Vaccine effectiveness (VE) in children vaccinated against influenza had a lower risk of
laboratory confirmed medically attended influenza illness than the unvaccinated children
▫ vaccinated children as compared with unvaccinated children was 86%
▫ partially vaccinated group was 73% as compared with the unvaccinated group
▫ This analysis shows that, TIV is highly effective in preventing laboratory-confirmed
influenza illness in children <5 years old, especially if administrated as recommended,
therefore every effort should be made to give two doses to children.
• Children under 5 will most likely be in some type of child care service where they tend to
be in close contact with other children, the 3 year old patient in the case study goes to
preschool two times a week where multiple kids were sick this study shows that if parents
would vaccinate their children every year it will reduce flu illnesses, but also preventing a
flu epidemic.
Diagnostic Tests for H3N2 seasonal Flu
• Early diagnostic tests done include a nasopharyngeal swab, washes
and aspirates
• A direct assay for virus
• Indirect assay for antibodies (hemagglutination for a specific
influenza virus)
Therapy and Prognosis for Seasonal H3N2
• The best way to alleviate symptoms from the flu in children are:
▫ Plenty of rest
▫ Lots of liquids
▫ Acetaminophen or ibuprofen for fever.
▫ Over the counter medication may be given to help with symptoms
but should not be given to children under 4.
• For healthy adults, the flu may be debilitating for a week or more.
After the infection has run its course, infected individuals are
expected to fully recover.
How to prevent the seasonal flu
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Influenza Vaccine
Avoid close contact with people that are sick
Stay home when you or your child is sick to not contaminate others
Always cover your mouth and nose during coughing or squeezing
Wash your hands
Avoid touching your eyes, mouth, or nose to prevent spreading of
germs
Epidemiology and Threats from H3N2
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Every year in the United States on average
At least 5 to 20 percent of the population get the flu
More than 200,000 people are hospitalized from flu-related complications
About 36,000 people die from flu-related causes
The flu virus can cause illness in people of any age group
Some people are more likely to have complications from the seasonal flu
▫ those of age 65 or older
▫ children younger than 2 years old
▫ people of any age who have chronic medical conditions
 Diabetics
 Asthmatics
 Lung disease
 Congestive heart failure
• Further complications can occur from the seasonal flu
▫ Bacterial pneumonia
▫ Dehydration
▫ Worsening of an individuals medical condition
Take Home Message
• The case study pertains to a 3 year old male that had a 4 day fever controlled with
Tylenol, he was fatigued, coughing, and had a reduction in urinary output. After
physical examination symptoms included a fever of 39˚C, bilateral conjunctivitis,
rhinorrhea, swollen lymph nodes, no rash, and feet edema.
• The most typical symptoms for the seasonal flu are rhinorrhea, fever of
approximately 39˚C, conjunctivitis, and swollen lymph nodes.
• The flu can be aerosol transmitted, H3N2 takes an incubation period of about three
days, and it can bind to a host cell in the upper respiratory tract. The ciliated epithelial
cells are lost due to viral multiplication, oxygen radical formation, and apoptosis.
• A diagnostic tests performed was a nasopharyngeal swab, washes, and aspirates. A
direct assay for virus. Indirect assay for antibodies (hemagglutination for a specific
influenza virus).
• Therapy is based on the severity of the infection. Rest and fluids are usually
recommended, as well as ibuprofen and acetaminophen to reduce the fever.
• Prognosis is good. If no secondary infection occurs, the patient will recover.
Complications include secondary infections which may cause problems such as
pneumonia, bronchitis or other respiratory problems.
• The best way to prevent the flu is get vaccinated, remember to wash your hands,
avoid close contact with people who are sick, and stay home so not to contaminate
others.
• Transmission of the flu is contacted from person to person.
• The seasonal flu will affect mostly the elderly, young children, and people who have
chronic medical conditions (e.g. diabetes, asthma, and congestive heart failure).
References
• http://www.cdc.gov/flu/protect/habits.htm
• http://pandemicflu.gov/individualfamily/about/seasonalflu/
• Joshi A.Y., et al, 2009, Effectiveness of inactivated influenza vaccine in
children less than 5 years of age over multiple influenza seasons: A case–
control study, Vaccine, 27:4457-4461.
• http://www.webmd.com/cold-and-flu/flu-guide/default.htm