The arrival of Ebola in Dallas could not have happened at a worse time for Texas Democrats, just weeks before the statewide election.

The fumbled handling of the first domestic case of the virus by a Dallas hospital and federal health officials — possibly leading to the death of the initial patient, the infection of two nurses and the potential exposure of others — is helping feed doubts about the leadership of President Barack Obama, whose sagging popularity was already a drag on Democratic chances.

But the political problem Ebola poses for Democrats in Texas, and in midterm elections nationally, could be even more fundamental. The Ebola story, in which an outsider brings disease to American shores, is the quintessential issue more likely to provoke a gut reaction from conservatives than liberals, and draw them to the polls, according to Rice University political scientist John Alford, a cutting edge researcher on the physiology of ideology.

“There are two things that conservatives are attuned to more and react to more — signals of threat and signals of disgust — so it’s a gift to the Republicans in this election that you’ve got exactly those two things dominating the national news,” Alford said. “Every time someone in the news is talking about projectile vomiting and diarrhea, I think, `The Republican vote just went up another half percent.’”

Alford’s work, published in leading peer-reviewed science journals, is part of a growing body of work cutting across the fields of political science, psychology and biology linking conservatism to more of a survival instinct.

“It’s a very well-positioned issue for the Republicans,” Howard Lavine, a University of Minnesota political scientist, said of the Ebola issue. “It activates both a threat and disgust response.”

A national study found a correlation between a state’s high level of “contamination disgust” — for example, people who were loath to drink from someone else’s soda or eat at a restaurant where the cook has a cold — and support for Republican John McCain in the 2008 presidential election, according to a 2011 article in the journal Social Psychological and Personality Science.

Social psychologist Ravi Iyer, chief data scientist for Ranker.com — a website where 18 million participants rate things and where Ebola was recently ranked the “scariest disease of all time” — said fear of Ebola is most pronounced in the conservative South.

Fear and disgust

Americans generally disapprove of the way Obama and the Centers for Disease Control and Prevention have handled the Ebola crisis so far, according to an Associated Press poll released Thursday. Republicans in Texas have seized on questions about the federal response to the disease.

Last week, Gov. Rick Perry and Texas Attorney General Greg Abbott, the Republican candidate for governor, and state Sen. Dan Patrick, the Republican candidate for lieutenant governor — who has been criticized by Democrats for past comments saying that immigrants illegally crossing the border were “bringing third-world diseases with them” — called for a ban on travel from Ebola-stricken nations in West Africa to the United States. State Sen. Wendy Davis, Abbott’s Democratic rival, said it ought to be “on the table.”

For conservatives, the Obama administration’s failure to contain Ebola is of a piece with its failures to contain the Islamic State militant group or secure the southwestern border or to even defend the White House perimeter from an intruder last month who made it to the East Room before being tackled by the Secret Service.

Texas’ voter identification law, which the Obama administration is fighting in court and Abbott is defending, comes under the same rubric. For conservatives, “ballot security has the same kind of emotional appeal,” said Alford, who was chosen by Abbott to be the state’s expert witness in the state and federal redistricting case.

Alford’s research with John Hibbing and Kevin Smith, both affiliated with the Political Physiology Lab at the University of Nebraska-Lincoln, and other collaborators, have found that conservatives tend to have a stronger startle reflex than liberals.

In an experiment they wrote about in 2008 in the journal Science, the researchers used eye movement sensors to determine that the political conservatives in their study tended to have a harder involuntary blink response to a startling noise, indicating a heightened “fear state.”

In this and another experiment, Alford and his colleagues also used sensors on the subjects’ fingers to measure changes in the skin’s conductance of electricity, a precursor to sweat, when they were confronted with a threatening image, such as a snake ready to strike, or with a disgusting image, such as maggots in an open sore.

In both cases, conservatives tended to have a stronger response to the images.

The stronger reaction to threat, the researchers found, is correlated with a more conservative stance on questions of national defense, border security and immigration, while the heightened sense of disgust correlates with a more conservative stance on gay marriage, abortion and other social issues.

‘Physiological perfect storm’

Both physiological responses are rooted in the survival instinct. A sudden noise might alert one to an imminent danger. “The role of disgust in the avoidance of disease, one of the primary sources of mortality over the years, makes it essential to survival,” Alford, Smith, Hibbing and three co-authors wrote in a 2011 article in PLOS One, the largest open-access science journal.

“When you make people fearful about disease, they become more wary of outsiders,” said Christopher Federico, a scholar at the University of Minnesota’s Center for the Study of Political Psychology. “It is how our distant ancestors would have coped with disease back when the evolutionary process was very harsh.”

While an Ebola scare might particularly rouse conservatives, Federico said it might also awaken that latent instinct across a broader swath of the electorate.

For Texas Democrats, the emergence of Ebola as an issue in an already challenging year is nothing but bad news.

“It’s a kind of physiological perfect storm,” Alford said. “I can’t think of an issue that you could pick that would be worse (for Democrats) for uniting those two traits. You could be physiologically disturbed by Ebola if you are a `threat conservative,’ or if you are a `disgust conservative,’ or, if you have both of those reactions.”

“If the Obama administration had acted decisively and been lucky, and basically handled this, it could have suppressed conservative reaction,” Alford said. But now, he said, “so close to the election, you get this kind of emotional reaction, there is basically no time to dampen that down by a successful policy response. It’s there, and this becomes the physiological backdrop to the decisions about turnout and vote direction and also the political discussion.”