From the Editor's Desk: West Nile Virus in the US: There Goes the Neighborhood

Robert Perrillo

This issue of the Ochsner Journal (Summer/Fall) has been long in coming. There are several reasons why this is so. The initial discussions of the Editorial Board about committing a topical issue to the West Nile virus (WNV) were laid in the late summer of 2001, when Louisiana stood in the epicenter of that season's outbreaks in the coastal South. Back then, the decision to proceed met with some skepticism by some members of the Board due to considerations that this would not be a significant health problem in the following year, and the medical significance of the outbreak had already been described, if not exaggeratingly so, in the lay medical press. Unfortunately, the infection HAS persisted in the United States since first described in 1999; and perhaps more importantly, the number of cases has increased dramatically this season and it has spread across the United States. This year, states that were previously spared or barely affected, such as Utah, Nevada, Colorado, New Mexico, Oregon, and California, may be vulnerable to this mosquito borne illness because of warmer-than-normal winter conditions followed by heat waves and drought. The other reason for the delay in coming to print was that as we gave further shape to the issue it became clear that it would be best if we could assemble a group of national as well as local experts in this disorder after there was enough data on the medical significance of the infection in the year 2002 as well as reasonable projections for the current year.

Our Guest Editor, Joe Dalovisio, head of the Ochsner Clinic and Alton Ochsner Medical Foundation Section on Infectious Diseases, inaugurates this issue with an overview of the WNV infection in the United States. It is interesting that the first cases were reported in New York City since the states that have been hit the hardest have been in the South and mid-West. One of the outside experts that we have assembled for this issue, Dr. James Sjevar of the Division of Viral and Ricketsial Diseases, Centers for Disease Control and Prevention, has written a fascinating article in which he describes that the first case occurred in Northern Uganda in 1937; this was followed by reports in the Mediterranean region in the 1950s and 1960s; and later on in the former Soviet bloc nations. As Dr. Sjevar points out, the WNV strain in the New York City cases was the same strain that had been reported in the Middle East. As the infection is conventionally spread by mosquitoes that have had a blood meal from an infected bird, it is possible that the first cases in New York City arose from a stowaway mosquito(es) traveling on an international jetliner. Although the vector is not the same, this is reminiscent of the recent SARS outbreak in Toronto and speculation about the first cases of AIDS that occurred in the Western hemisphere a number of years ago. The message seems to be that in today's day of rapid international travel, novel infections are apt to occur in geographic areas where they previously did not exist, and as a corollary to this it is precisely these infections which we are initially least prepared to deal with medically. This is underscored in the article on the diagnosis and treatment of West Nile infection by Dr. Sandra Kemmerly, from the Ochsner Section on Infectious Diseases. Much of Dr. Kemmerly's article deals with methods to diagnose the condition, and relatively little information is available on the means to treat this condition. Surprisingly, there have been no controlled studies of the use of interferon or ribavirin, a nucleoside with broad antiviral properties. I suspect that this or another class of antivirals will be used in controlled clinical trials by this time next year. Equally interesting would be to see if immune globulin harvested from convalescent donors would prove effective in ameliorating some of the serious neurologic side effects. Until then, the major message remains prevention, prevention, prevention!

In this issue, Drs. Om Prakash and George Pankey of the Sections of Laboratory Molecular Oncology, and the Section on Infectious Diseases, respectively, also provide an excellent overview of disease pathogenesis of the WNV and mention other members of the genus Flaviviridae. While infections with some of the Flaviviruses may seem unlikely in the United States, occurring primarily in remote regions of the world, others such as St. Louis encephalitis have already left their mark in the United States. While the hepatitis C virus is not discussed in their article, I would like to note that it is another important member of this genus, and fortunately, here studies in which mosquitoes were allowed to feed on infected units of blood have not shown them to be a plausible vector for cases where there is no known means of exposure. Also in this issue is a description of the West Nile Epidemic in Louisiana in 2002 by Dr. Gary Balamso and colleagues from the Louisiana Office of Public Health. This informative articles delineates the case description that was used to confirm West Nile infection and to separate instances of infection from disease, which is an important piece of documentation since most infections are either clinically inapparent or overlap with other viral infections. Finally, Dr. Jay Van Gerpen provides an excellent clinical summary of the neurologic complications of West Nile virus infection as it occurred in Louisiana in 2002. Whereas only a small number (1/150) of those infected with WNV have serious neurologic sequelae, Dr. Van Gerpen's article delineates that the disease can present as a case of encephalitis, meningitis, and acute flaccid paralysis, either alone or in combination. We feel confident that this issue of The Ochsner Journal will provide an up-to-date summary of an illness which will unfortunately probably hang around for a number of years. No doubt, WNV will ultimately move into relative medical obscurity as we develop methods of passive or active immunization and/or treatment. It is difficult to know, however, who will require immunoprophylaxis as the disease becomes more widespread throughout the North American continent. I hear they even have huge mosquitoes in Alaska!