AIDS and HIV - Solution

by
Erik Oosterwal



The key to finding the solution to this puzzle is dicovering the initial source of the infection. Just for the sake of this puzzle, we will assume that each person is considered not at risk until some action in the puzzle mentions a risky behavior with a known high risk person.  The first step in solving the proble is to draw up a chart with dates and check off each action based on the linear time:

Risky Behavior Timeline


Now we move from left to right and compare the action at each date to see if that action denoted a risky bahavior and whether or not the partner in that behavior was already a high risk person or not.

10 Risky behavior, but not with a high risk partner. Not at risk.
5 Risky behavior, but not with a high risk partner. Not at risk.
9 Risky behavior with a known HIV positive partner. Yes--at risk.
12 Risky behavior, but not with a high risk partner. Not at risk.
1 Risky behavior, but not with a high risk partner. Not at risk.
6 Not a risky behavior. Not at risk.
7 Risky behavior with a partner (9) who had previously engaged in high risk behavior with a known HIV case. Yes--at risk.
15 Risky behavior, but not with a high risk partner. Not at risk.
13 Risky behavior with a high risk partner (9) who had previously engaged in high risk behavior with a known HIV positive person. Yes--at risk.
17 Risky behavior with a not at risk partner. Not at risk.
20 Risky behavior with a partner (7) who had previously received blood from a high risk person (9) who had previously engaged in high risk behaviorwith a known HIV positive person. Yes--at risk.
18 Not a risky behavior. Not at risk.
19 Risky behavior with a partner (7) who had previously received blood from a high risk person (9) who had previously engaged in high risk behavior with a known HIV positive person. Yes--at risk.
2 Not a risky behavior. Not at risk.
4 Risky behavior with a partner (13) who had previously shared a needle with a high risk person (9) who had previously engaged in high risk behavior with a known HIV positive person. Yes--at risk.
14 Not a risky behavior (assuming partner (19) is not also bleeding.) Not at risk.
16 Risky behavior with a high risk partner(4) who had previously shared a needle with a high risk person (13) who had previously shared a needle with a high risk person (9) who engaged in high risk behavior with a known HIV positive person. Yes--at risk.
3 Risky behavior with a partner (20) who had previously received blood from a high risk person (7) who had previously received blood from a high risk person (9) who had previously engaged in high risk behavior with a known HIV positive person. Yes--at risk.
8 Risky behavior with a high risk partner (4) who had previously shared a needle with a high risk person (13) who had previously shared a needle with a high risk person (9) who had previously engaged in high risk behavior with a known HIV positive person. Yes--at risk.
21 Risky behavior with a high risk partner (3) who previously received milk from a high risk person (20) who previously received blood from a high risk person (7) who previously received blood from a high risk person (9) who had previously engaged in high risk behavior with a known HIV positive person. Yes--at risk.
22 Not a risky behavior. Not at risk.
11 Risky behavior with a high risk person (4) who previously shared a needle with a high risk person (13) who previously shared a needle with a high risk person (9) who had previously engaged in high risk behavior with a known HIV positive person. Yes--at risk.



All original puzzles and solutions are © Erik Oosterwal 1993-2008

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