Surveillance, Investigation and Analysis of Human Leptospirosis Infections in Taiwan, 2009-2010

u-Chun Chiu, Shih-Hui Chiu, Hsiu-I Wang, Jung-Jung Mu

2011 Vol.27 NO.16

Correspondence Author: Shu-Chun Chiu


Leptospirosis is a Category IV notifiable or reportable communicable disease in Taiwan. It is a zoonosis and caused by a bacterium commonly referred to as leptospires. The bacterium usually excreted by animal carrier through urination. The bacterium can survive for more than a month in water. The bacterium enters and infects humans when contaminated food or water is ingested or passing through skin wound and mucous membrane when the victim is swimming or playing in contaminated water. In 2009, typhoon Morakot brought a catastrophic flood in areas of southern Taiwan including parts of Kaohsiung County and City as well as Pingtung County and City. Many clustering infections of leptospirosis broke out in flooded areas and had drawn attention of people.
In this study, we analyzed the prevalence of human leptospirosis in Taiwan over the two-year period of 2009 and 2010. We noticed that the leptospirosis infection in Taiwan was significantly higher in males. However, there was no significant difference to the people live in urban or rural area. Also, no seasonal variation was found in the prevalence. Similar to other countries, the epidemiological data suggested flooding problem caused by natural disasters is the primary factor to cause clustering infection of leptospirosis. We noticed that the monthly positive rate revealed by the notification system stayed lower than 10% throughout the period except the three months in 2009 when many clustering cases showed up, with confirmed rates of 18.5~39.7% , after the flooding brought up by typhoon.
Besides continuing leptospirosis surveillance, the health authorities should strengthen the leptospirosis prevention campaign before the typhoon season to alert people and lower the infection risk. Meanwhile, since symptoms of leptospirosis are quite similar to common cold, yet the transmission routes are different, the clinicians should also look into the situation of patient’s other family members, the patient’s occupation, and residential environment before collecting specimen and reporting the suspect leptospirosis. This shall facilitate sorting the infection source and controlling the endemic, and also avoid wasting of the medical resources.