One month later, in March 2002, Karlene Keogh called 911 when her husband had two seizures at their home similar to the one he had been stricken with at St. Joe's.
Kevin Keogh was readmitted to the hospital on March 11, 2002, in an "extremely agitated and confused" state. Doctors immediately ordered another test to see if Keogh had the worms in him.
This time, they had the results within hours.
According to Dr. Clark, an "equivocal, but very suspicious" finding for cysticercosis had arisen in the test.
What "equivocal" meant was that the results were just short of being able to say for sure that Keogh was carrying the worms.
Clark put Keogh on Albendazole, a drug used to kill the pork tapeworm, and Dilantin, a powerful medication used to control seizures.
The patient returned to St. Joe's a month later for a follow-up visit.
Afterward, Dr. Clark wrote that Keogh "still has symptoms, but minimized them. He states they are resolved. His wife, in the room, does take issue with a lot of his comments. . . . Major denial about his symptoms. Probable seizure disorder, temporal lobe. Possible [cysticercosis]."
All the while, Keogh continued to keep his medical troubles from everyone at City Hall, except for a few trusted colleagues.
Around that time, it was reported that two financial services had awarded Phoenix Sky Harbor Airport its highest credit rating a great victory for the city in the aftermath of the 9/11 attacks.
"I am elated and believe we deserve this rating," Keogh told a reporter.
Later that summer, Keogh was examined by Dr. David Treiman, a seizure specialist at Barrow Neurological Institute.
Treiman concluded, "My impression is that this patient has epilepsy, manifested as two complex partial seizures, probably secondary to cysticercosis, even though his MRI scans have been normal."
According to a medical journal, such seizures "cause impaired consciousness and arise from a single brain region. . . . During a complex partial seizure, the patient may not communicate, respond to commands, or remember events that occurred. [But] some patients may continue to perform complex motor behaviors such as operating a car."
Writes Dr. Orrin Devinsky, an editor of the Web site epilepsy.com, "Even though the person's eyes are open and they may make movements that seem to have a purpose, in reality nobody's home. Some people do things during these seizures that can be dangerous or embarrassing, such as walking into traffic or taking their clothes off."
Karlene Keogh says symptoms of her husband's mystery illness would subside for stretches after he completed the drug regimen for cysticercosis and continued on the Dilantin.
The couple even vacationed in Europe in 2003.
As 2004 began, the City of Phoenix was in the middle of several huge money deals in which Keogh's abilities were being put to the test.
His many tasks included coordinating the sale of $500 million in revenue bonds to pay for the light-rail system.
The city also was sorting out how to finance the proposed $350 million downtown hotel. Also pending was a $180 million sale of wastewater revenue bonds.
No one at City Hall seemed to have the slightest doubt that Keogh and his staff would put it all together, just as they always had.
Karlene Keogh says her husband's "symptoms," by which she meant what he had been complaining about on and off since the Mexico trip, reappeared in early 2004.
Keogh's appetite vanished, his stomach and head ached, and he constantly was getting sinus infections and sore throats. Never the best sleeper, he was more restless at night than ever.
Mrs. Keogh says he complained of not being able to concentrate at work nearly as well as he always had.
That June, Keogh was too ill to take his wife out for her birthday. He made an appointment with Dr. Barry Hendin, co-director of Banner Good Samaritan's department of neurophysiology.
During that visit, according to Dr. Hendin's notes, Keogh asked him "to review my situation relative to prior problems with cysticercosis."
The doctor noted that Keogh's symptoms were "suggestive of cysticercosis, [but] without any definitive positive diagnostic studies" to back it up.
Hendin ordered another MRI, as well as an EEG test, the latter to look for irregularities in the brain's electrical activity that may produce seizures. Surprisingly, the doctor did not request an updated test for parasites.
The EEG came up normal.
In October, Keogh received a 7 percent salary increase, to just under $165,000 a year.
His supervisor, Sheryl Sculley (now the city manager in San Antonio, Texas), was glowing in her praise, writing that "you are creative and always willing to figure out a financing strategy. [You are] analytical, creative and outstanding on financial matters."