Primarily used for the detection of arthropod-borne viruses such as St. Louis Encephalitis (SLE), Eastern Equine Encephalomyelitis (EEE), Western Equine Encephalitis (WEE), West Nile Virus (WNV), and La Crosse (LAC). Disease surveillance is performed throughout the mosquito season by the biologist/entomologist and/or inspector(s), and is accomplished using one or several of the following:
A. Vertebrate Host Surveillance
1. Sentinel flocks (chicken, quail, pheasant), a common means of surveillance employed by organized mosquito control in Louisiana, are established and routinely serologically tested throughout the mosquito season.
2. Free ranging wild birds are captured using walk-in traps, ground mist nets or other trapping devices and are bled, banded and released for possible later recapture to check seroconversions (primarily for EEE, SLE, WEE and WNV).
3. Nestling birds are bled and banded to provide early-season indication of transmission intensity.
4. Equine cases in areas with susceptible horse populations may provide a practical and sensitive tool for recognition of potential public health problems (EEE, WNV, WEE). Veterinarians are required to report to the state veterinarian the occurrence of suspected equine cases.
5. Wild mammals (rodents, squirrels, rabbits, etc.) are captured and blood samples taken for serology testing (LAC, Keystone virus, WNV).
B. Vector Surveillance
1. Adult mosquito species, density, age structure and minimum infection rates (MIR) are monitored (see section I. B. Adult mosquito surveillance above for adult surveillance).
2. Adult mosquitoes are collected, placed in pools of 10-50 and sent to the laboratory for virus isolation.
3. Vec Test Kits may be used in-house to test for West Nile virus and St. Louis Encephalitis virus.
4. State and local public health officials need to be contacted immediately if evidence is found of increased arbovirus activity in a mosquito or vector host population.
C. Human Case Surveillance
1. Contacting State Public Health Officials
a. Immediately contacted by Louisiana Veterinary Medical Diagnostic Laboratory - Arboviral Surveillance Laboratory, School of Veterinary Medicine, Louisiana State University (LVMDL) if evidence is found of increased arbovirus activity in a mosquito or vector host population.
b. Vector Control Officials shall notify immediately the Office of Public Health, Infectious Disease Epidemiology Section should evidence of increased activity be learned through sources other than LVMDL.
2. Contacting Vector Control Officials
a. The Infectious Disease Epidemiology Section of the Office of Public Health will notify vector control officials of laboratory confirmed suspect human cases of arboviral encephalitis within the respective mosquito control districts.
b. Vector control officials should contact the Infectious Disease Epidemiology section for information concerning suspected human cases in their jurisdictions.
3. Contacting Parish Officials
a. Regional public health officials will report confirmed human cases to parish officials.
D. Louisiana ARBONET - A Web site (Websites) hosted by Tulane School of Public Health and Tropical Medicine (TSPHTM) in collaboration with the LMCA, DHH/OPH and LSU School of Veterinary Medicine.
1. TSPHTM maintains a repository of laboratory information concerning all animal surveillance, including mosquitoes.
2. TSPHTM coordinates the sharing and reporting of information to all parties concerned.
E. Operational Factors
1. Mosquito pool specimens, sentinel chicken blood samples and blood samples from a number of wild birds can be submitted to the LVMDL for arbovirus surveillance testing as resources are available.
2. Should a mosquito control district establish a laboratory for serologic screening, arrangements can be made with CDC to transfer existing Enzyme-Linked Immunosorbent Assay (ELISA) technology and reagents, and to obtain appropriate training (see Websites).
3. The biologist/entomologist shall, with the assistance of inspector(s), routinely perform disease surveillance activities throughout the mosquito season (normally from March through October, depending on climatic conditions).
4. Both federal and state permits shall be required when obtaining blood samples from the wild and when banding (see More Resources at right).