Correspondence

Correction

Flavivirus Encephalitis

N Engl J Med 2004; 351:1803-1804October 21, 2004

Article

To the Editor:

In his excellent review of flavivirus encephalitis (July 22 issue),1 Solomon asserts that Murray Valley encephalitis virus causes disease in New Zealand. Until now, we have been unaware of any reports of flavivirus encephalitis in New Zealand, but we do acknowledge the possibility.2 At least one local species of mosquito, Culex quinquefasciatus, is a competent vector of Murray Valley, West Nile, and St. Louis encephalitis viruses. No vector of Japanese encephalitis virus has been recognized here. Incursions of the diseases, introduced by travelers or migratory birds, may not be detected until an outbreak occurs in humans, because serologic monitoring of vertebrate hosts for flavivirus is not routinely performed.3 We recently saw a severe case of Japanese encephalitis in an unvaccinated, middle-aged woman who had returned from a four-week organized tour of Japan and China (including a Yangtze River cruise). Even if she had sought advice before departure, vaccination might not have been recommended against Japanese encephalitis. Solomon could have mentioned a strategy of offering such vaccination to short-stay tourists undertaking high-risk activities and could have emphasized the importance of measures to avoid mosquito bites.4

Rupert Handy, M.B., Ch.B.
Selwyn Lang, F.R.A.C.P., F.R.C.P.A.
Middlemore Hospital, Auckland 1006, New Zealand

4 References

1. 1

   Solomon T. Flavivirus encephalitis. N Engl J Med 2004;351:370-378
   Full Text | Web of Science | Medline

2. 2

   Weinstein P, Laird M, Calder L. Australian arboviruses: at what risk New Zealand? Aust N Z J Med 1995;25:666-669
   CrossRef | Medline

3. 3

   Broom AK. Sentinel chicken surveillance program in Australia, July 2002 to June 2003. Commun Dis Intell 2003;27:367-369
   Medline

4. 4

   Centers for Disease Control and Prevention. Health information for international travel, 2003-2004: encephalitis, Japanese. (Accessed October 1, 2004, at http://www.cdc.gov/travel/diseases/jenceph.htm.)
   

Author/Editor Response

I thank Drs. Handy and Lang for their clarification. Although at least one competent mosquito vector of Murray Valley encephalitis virus is found in New Zealand, no disease due to this virus has been recognized to date. The question of which travelers to Asia should be vaccinated against Japanese encephalitis remains controversial.1 Although the chances of infection are small, the effects can be devastating, and many who have seen patients with the disease advocate more liberal use of the vaccine than is recommended in the current guidelines of the Centers for Disease Control and Prevention Advisory Committee on Immunization Practices.2 Furthermore, the only internationally approved vaccine is the mouse-brain–derived, formalin-inactivated vaccine, which is expensive, cumbersome to produce, and associated with side effects. New vaccines are needed, for both travelers to and residents of Asia. Unfortunately, space constraints did not allow me to discuss other protective and control measures in my article. Such measures include avoidance of mosquito bites, zoo-prophylaxis, use of natural insecticides (such as neem cake), placement of larvivorous fish in rice paddies, and intermittent irrigation of rice paddies to control mosquito breeding.3

Tom Solomon, M.D., Ph.D.
University of Liverpool, Liverpool L9 7LJ, United Kingdom
tsolomon@liv.ac.uk

3 References

1. 1

   Shlim DR, Solomon T. Japanese encephalitis vaccine for travelers: exploring the limits of risk. Clin Infect Dis 2002;35:183-188
   CrossRef | Web of Science | Medline

2. 2

   Inactivated Japanese encephalitis virus vaccine: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Morb Mortal Wkly Rep 1993;42:1-15
   Medline

3. 3

   Solomon T. Vaccines against Japanese encephalitis. In: Jong EC, Zuckerman JN, eds. Travelers' vaccines. Ontario, Canada: B.C. Decker, 2004:219-56.
   

Citing Articles (1)

Citing Articles

1. 1

   Chih-Cheng Lai, Wen-Lun Liu, Shih-Chang Lin, Yao-Chuan Hsiao, Liang-Wen Ding. (2008) Diagnostic MR Images of Japanese Encephalitis. The Journal of Emergency Medicine 35:3, 305-307
   CrossRef