Guest researcher gives presentation on dengue virus

Dengue outbreaks occur in various places throughout the world, mostly in urban areas. (World Health Organization)

MaryAnne Curry Shults

The dengue virus has emerged as the most important mosquito-transmitted virus in the world. This was the topic of the second lecture in the science series hosted by the Math, Science and Engineering division of Saddleback College last Friday.

Guest speaker Richard Kuhn, head of the biological sciences department at Purdue University gave a comprehensive presentation to a crowd of about 75 curious students, faculty and staff.

“I’m interested in medicine and biology,” said Brett Larson, 35, a soon-to-be graduate student in physician assistant studies. “I’m also interested in the development of scientific research to aid prevention and treatment of disease.”

Kuhn dedicated the lecture to his friend and colleague Richard McCullough, former president, dean and instructor at Saddleback.

Kuhn and McCullough met five years ago and struck up a friendship. Kuhn said the two men shared a lab at Purdue.

“[McCollough] has a passion for education. He loves Saddleback College,” Kuhn said. “He single-handedly changed Saddleback. It’s been a remarkable change.”

Dean Jim Wright shared a brief biographical sketch of McCullough, crediting him for his nearly 40 years at the college in various roles, including setting up the electron microscopy lab, the solar observatory, as well as McCullough’s efforts initiating the Veteran’s Memorial project. Wright also enlightened the audience saying McCollough once said to always be kind to people. This rang true as the two men often switched roles as dean-to-instructor and vice versa.

“He began teaching at Saddleback in 1971,” said Wright. “He taught everything in the biology department except botany.”

Presenting McCollough with a formal certificate as a memento, Wright dubbed the lecture the “first official Richard McCollough Lecture.”

The lecture began with Kuhn explaining basic information about the dengue virus. He said scientists don’t really know its origin, but assume it came from Africa.

The Center for Disease Control reports with more than one-third of the world’s population living in areas at risk for transmission, dengue is a leading cause of illness and death in the tropics and subtropics. As many as 100 million people are infected yearly. Dengue is caused by any one of four related viruses transmitted by mosquitoes.

Kuhn said dengue is spread by “urban mosquitoes,” because it is found in more densely populated areas, and not necessarily in areas with high poverty. He warned that up to 2.5 billion people worldwide are at risk.

Dengue has emerged as a worldwide problem only since the 1950s. Although dengue rarely occurs in the continental U.S., it is endemic in Puerto Rico and in many popular tourist destinations in Latin America and Southeast Asia with periodic outbreaks occurring in Samoa and Guam.

“The CDC is worried about the spread of dengue from tourists coming into the U.S.,” Kuhn said.

There are not yet any vaccines to prevent infection and the most effective protective measures are those that avoid mosquito bites. However, there are several vaccines in various stages of clinical trials.

Kuhn said 87 percent who contract the virus will have no symptoms, which include fever, headache, joint pain, vomiting and rash, but seldom causes death.

Some develop dengue hemorrhagic fever, or DHF. According to the World Health Organization, it is the leading cause of serious illness and death among children in some Asian countries. DHF is a potentially deadly complication that is characterized by high fever, often with enlargement of the liver, and in severe cases circulatory failure. The illness often begins with a sudden rise in temperature accompanied by facial flush and other flu-like symptoms. The fever usually continues for two to seven days and can be as high as 106 F, possibly with convulsions and other complications.

“Dengue makes influenza seem mild,” Kuhn said. “Patients with even mild dengue say they literally want to die because the pain is so bad.”

When infected, early recognition and prompt supportive treatment can substantially lower the risk of developing severe disease.

After explaining the virus for those with an understanding of microbiology, Kuhn acquainted the audience with the details of his laboratory’s work and how it specifically ties into establishment of a vaccine.

“The virus is far more complex than we originally thought,” Kuhn said. “We study basic biology to design antivirals and better vaccines.”

As the PowerPoint and projector shut off, and the house lights came up, Larson felt he’d learned a great deal during the 90-minute lecture.

“It was very interesting, informative, and a little confusing,” Larson said. “But developments are being made and that’s what is important.”

This informational flier is a public service informational flier about the dengue virus. (World Health Organization)

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