Murder by HIV?
Grades 5–8 Edition
by
Michèle I. Shuster
Department of Biology
New Mexico State University, Las Cruces, NM
Naowarat (Ann) Cheeptham
Department of Biological Sciences
Thompson Rivers University, Kamloops, B.C., Canada
Laura B. Regassa
Department of Biology
Georgia Southern University, Statesboro, GA
Key Concepts and Background
• Basic knowledge of HIV and what happens
during an HIV infection (see next slides for a
brief re-cap)
• Genetic relationships and phylogenetic trees
– # of genetic differences indicates distance
– Reading nodes/common ancestors on
phylogenetic trees
HIV Infection
• Infects, replicates, infects, replicates
• Every time
– Chance for mutation
– “Typo” during replication
• So within the body
–
–
–
–
Many RELATED strains of HIV
All descended from original (infecting) strain
All related to each other
All related to the infecting strain
Over time:
genetically diverse population
Early
Later
Even Later
The Case
State of Louisiana vs.
Richard J. Schmidt, MD
• Dr. Schmidt was having an affair with a nurse in
his office
• On-going for 10 years
• During this time
– He gave her injections
– Vitamin B-12
• She broke off the relationship (July 1994)
• August 4, 1994
– He showed up and gave her a “B-12” injection
– Against her will
January 1995
• She tested positive for HIV
• Question: Was this a new or old infection?
– She was a regular blood donor (HIV testing)
– Last blood donation—April 1994
– She was HIV negative
• Accusation…
April 1994
No HIV
Blood donation
January 1995
HIV positive
August 1994
Injection by
Doc/boyfriend
January 1995
Nurse accused
boyfriend of
infecting her
Investigation
• Doctor’s office
• Hidden blood-draw record
– HIV positive patient
– Blood drawn on August 4th, 1994
– Blood not sent to lab
– Staff were told to hold the tube of blood for the
doctor
August 4, 1994: Blood
drawn from HIV-positive
patient at Doc’s office
April 1994
No HIV
Blood donation
January 1995
HIV positive
August 4, 1994
Injection by
Doc/boyfriend
January 1995
Nurse accused
boyfriend of
infecting her
Questions
• Is Nurse’s (victim) HIV related to the patient’s
HIV?
• Is Nurse’s (victim) HIV related to other HIV
strains in LA?
• Is Nurse’s (victim) HIV related to other strains
of HIV in the U.S.?
Based on the questions
• What are some hypotheses?
• How can these be tested?
• What do you need in order to test these?
Draw Blood and Obtain HIV Sequences
• HIV positive patient
– Possible source
• Nurse
– Victim
• HIV positive people from the same city in LA
• HIV positive person from the U.S. (not LA)
If Doctor injected Nurse with Patient HIV…
• Which will be most closely related?
A. Victim HIV and Patient HIV
B. Victim HIV and LA cases HIV
C. Victim HIV and USA HIV
Let’s Build the Tree
• Go online to MUSCLE:
http://www.ebi.ac.uk/Tools/msa/muscle/
• We will import HIV sequences
– The pol gene
– From patient HIV, from Victim HIV, from “other”
HIV
Copy/Paste Sequences from HIV
Sequence file
Paste Here
Then hit “Submit”
Submit
You will need the .txt file from the supplemental materials for the sequences to copy and paste.
Wait……
Wait… then you will get this—
click on “Result Summary”
Then click on “Start Jalview”
Then you’ll get this
An alignment of all the sequences
•Patient (possible source)
•Victim (the nurse)
•LA (random HIV from LA)
•USA (random HIV from the US)
Click on Calculate…
Calculate
• Calculate Tree
– Average Distance/ BLOSUM 62
Last Common Ancestor between
Patient strains and Victim (Nurse)
strains?
Last Common Ancestor
between Patient strains and
LA strains?
Last Common Ancestor
between USA strain and LA
strains?
So which HIV is more closely
related to the Nurse’s HIV?
A. Patient HIV
B. LA HIV
C. USA HIV
So what is most
likely source of
Nurse’s HIV?
So what can we conclude?
Jury Agreed
• So did the LA Court of Appeals
• So did US Supreme Court
• Sentence Upheld
– 50 years of hard labor
• Don’t underestimate the power of the
phylogenetic tree!
August 4th, 1994: Blood
drawn from HIV-positive
patient at Doc’s office
April 1994
No HIV
Blood donation
January 1995
HIV positive
August 4, 1994
Injection by
Doc/boyfriend
January 1995
Nurse accused
boyfriend of
infecting her
1998
Doc convicted
50 yrs of hard labor
2002
US Supreme Court
Upheld conviction
2000
LA Court of Appeals
Upheld conviction