ABSTRACT

Overview of surveillance types Until the 1950s the word surveillance was only applied to a person with a disease entity such as plague and involved appropriate community alertness to keep that person quarantined and away from other, noninfected people. After World War II, that definition was changed with the formation of the U.S. Communicable Disease Center (now the Centers for Disease Control) to mean a disease or condition instead of a sick person.1 This change fundamentally altered the way public health departments conducted disease surveillance. Under this new paradigm, public health entomologists are often charged with surveillance for vector-borne diseases (VBDs), which may include collecting arthropod specimens and testing them for various disease agents such as Lyme spirochetes, spotted fever group rickettsiae, ehrlichial organisms, and trypanosomes, among others. However, in most state public health programs, surveillance is primarily focused on mosquito-borne arboviruses such as those causing encephalitis. There is no one-size-fits-all arbovirus surveillance model. Some states have no vector surveillance of any kind, with little hopes of establishing one.2 Therefore, in each state, surveillance systems must be tailored according to the probability of arbovirus activity and the reality of available resources. In states without any preexisting VBD programs, developing a new avian-based or mosquito-based arbovirus surveillance systems may be required. For some projects, previously abandoned surveillance systems may need to be resurrected. In others, modification or strengthening of existing systems (e.g., for detection of West Nile virus (WNV), eastern equine encephalitis (EEE), western equine encephalitis (WEE), or St. Louis encephalitis (SLE)) may be the most appropriate response. States with low probability of arbovirus activity or lack of resources to support avian-based or mosquito-based surveillance may just conduct hospital or clinic surveillance for neurologic disease in humans and equines. Freeaccess information on how to establish surveillance programs is available online. Examples include the CDC Guidelines for Arbovirus Surveillance Programs in the United States,3 CDC Epidemic WNV in the United States,3a and the WHO chapter entitled “Entomology in Public Health Practice.”4 The following discussion utilizes information contained in those documents. Appropriate response(s) to surveillance data is the key to preventing

human and animal disease associated with mosquito-borne arboviruses. That response must be immediate and effective mosquito control in the local area if virus activity is detected in the bird, mosquito, or human surveillance systems.