By the Numbers: West Nile Versus Flu

West Nile virus made national news recently with an announcement from the Centers for Disease Control and Prevention.

“We're in the midst of one of the largest West Nile virus outbreaks ever seen in the United States,” said Dr. Lyle Petersen, who is the director of the Division of Vector-borne Infectious Diseases at the CDC.

We are hearing more about West Nile virus and the cases of the virus being found on our doorstep. Each weekday, the Pennsylvania West Nile Control Program releases more positive test results of West Nile found in mosquitoes, bird and other animals. Within the recent weeks, they’ve been reporting human cases including

Other than the news reports and the desire to keep away from painful mosquito bites, most people haven’t had too much interaction with West Niles, because even though we hear about the recent cases, the majority of what is being reported are mosquitoes testing positive for the virus. This year, 2,307 mosquito samples tested positive statewide and nine humans tested positive, according to the West Nile Virus Control Program.

On the other hand, something everyone has had contact with in some form or another is the flu.

“There is no validity to comparing the number of cases of influenza to the number of cases of West Nile as a basis to determine the relative importance of these two diseases.  Both represent significant public health concerns that we closely monitor,” said Holli Senior, Deputy Press Secretary for the Pennsylvania Department of Health.

Medical experts can debate the importance of the diseases, but seeing the number of cases and deaths reported to the Department of Health can help give the rest of us some context.

“They are two completely different viruses and more importantly their modes of transmission are different. Flu can be transmitted from person to person while West Nile Virus is transmitted by infected mosquitoes. In addition, for both diseases the number of reported cases represents a fraction of the actual number of infections that occur,” Senior said.

Data provided by the Pennsylvania Department of Health based on the virus' "season." Flu numbers are taken from Oct. 1, 2011 through July 31, 2012 and West Nile virus numbers are taken from Jan. 1, 2012 through Aug. 24, 2012.