Murder by HIV?Grades 5–8 EditionbyMichèle I. ShusterDepartment of BiologyNew Mexico State University, Las Cruces, NM

Naowarat (Ann) CheepthamDepartment of Biological SciencesThompson Rivers University, Kamloops, B.C., Canada

Laura B. RegassaDepartment of BiologyGeorgia 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

EarlyEarly LaterLater Even LaterEven 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 1994No HIV Blood donation

August 1994Injection by Doc/boyfriend

January 1995HIV positive

January 1995Nurse 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

April 1994No HIV Blood donation

August 4, 1994Injection by Doc/boyfriend

January 1995HIV positive

January 1995Nurse accused boyfriend of infecting her

August 4, 1994: Blood drawn from HIV-positive patient at Doc’s office

August 4, 1994: Blood drawn from HIV-positive patient at Doc’s office

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 HIVB. Victim HIV and LA cases HIVC. 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 HereThen 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 thisAn 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 Victim (Nurse) strains?

Last Common Ancestor between USA strain and LA strains?

Last Common Ancestor between USA strain and LA strains?

Last Common Ancestor between Patient strains and LA strains?

Last Common Ancestor between Patient strains and LA strains?

So which HIV is more closely related to the Nurse’s HIV?A. Patient HIVB. LA HIVC. USA HIV

So which HIV is more closely related to the Nurse’s HIV?A. Patient HIVB. LA HIVC. USA HIV

So what is most likely source of Nurse’s 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!

April 1994No HIV Blood donation

August 4, 1994Injection by Doc/boyfriend

January 1995HIV positive

January 1995Nurse accused boyfriend of infecting her

August 4th, 1994: Blood drawn from HIV-positive patient at Doc’s office

August 4th, 1994: Blood drawn from HIV-positive patient at Doc’s office

1998Doc convicted50 yrs of hard labor

1998Doc convicted50 yrs of hard labor

2000LA Court of AppealsUpheld conviction

2000LA Court of AppealsUpheld conviction

2002US Supreme CourtUpheld conviction

2002US Supreme CourtUpheld conviction