Mosquito Surveillance

1. Mosquito Surveillance Greg Chrislip West Virginia Department of Health and Human Resources

2. 2004 Mosquito Surveillance • A total of 43 species are shown to be positive for West Nile virus in 2004. • Genera that tested positive included: • Aedes (4 species), Anopheles (6 species), Coquillettidia(1 species),Culex (8 species),Culiseta (2 species), Deinocerites (1 species),Ochlerotatus (15 species),Orthopodomyia (1 species), Psorophora (4 species), and Uranotaenia (1 species).

3. West Virginia Mosquitoes • 28 Species native to WV • Genera include: Aedes(3 species), Anopheles (3 species), Coquillettidia (1 species), Culex (5 species), Culiseta (1 species), Ochlerotatus (9 species), Orthopodomyia (1 species), Psorophora (3 species), Toxorhynchites (1 species), Uranotaenia (1 species).

4. Most Common West Virginia Mosquitoes Collected 2003 • Container Breeders • Ochlerotatus japonicus • Ochlerotatus triseriatus • Others • Culex pipiens • Culex restuans • Aedes vexans • Anopheles punctipennis

5. WHY? • Why do you test for disease in animals (dead birds, arthropods, horses) when you know it is there? • Answer: SURVEILLANCE • Etymology: French, from surveiller to watch over, from sur- + veiller to watch, from Latin vigilare, from vigil watchful -- more at VIGIL: close watch kept over someone or something (as by a detective); also: SUPERVISION

6. SURVEILLANCE • Surveillance answers other questions. Yes we know that it is there. • But how much? • Is it in epidemic proportions in wild animals? • If the infected number of animals or mosquitoes, for example, is increasing, then we may be facing a spillover into the human population.

7. Knowing what is going on in animals and mosquitoes gives us a “head’s – up” that people are at a greater risk of becoming ill with these infections.

8. Objectives • Identification of the mosquito species that are present in an area. • Determining whether they are important vector species. • Identification and mapping of mosquito breeding habitats for larval control purposes. • Defining the geographic area affected by mosquitoes originating from identified habitats.

9. Objectives (cont.) • Determining the population density. • Determining when mosquito populations are at the appropriate developmental or behavioral stage to apply control measures. • Determining the effectiveness of local mosquito control measures.

10. Objectives (cont.) • Determining whether vector mosquito species are present in an area; whether they are infected with arboviruses. • Determining the mosquito infection rate for arboviruses in vector species populations. • Determining the seasonal activity patterns of local mosquito species.

11. Mosquito Biology • 4 distinct stages in their lifecycle • Egg, larva, pupa and adult • “Most” females blood feed • Over 3,000 species world-wide

13. Female Mosquito (Cx. quinquefasciatus) Blood Feeding on a finger

14. Culex Mosquito laying eggs Egg raft

15. Siphon Culex–type Mosquito Larvae “ wigglers” (Aedes, Culex, Ochlerotatus and Psorophora)

17. Modified siphon for piercing plant stems/roots Plant stem or root Coquillettidia and Mansonia

18. Anopheles No siphon

19. Larval Surveillance Procedures • The Shallow Skim • Partial Submersion • Complete Submersion • Dipper as a background • Flow-in-method • Scraping • Simple scoop

20. Larval Surveillance • Assist with locating breeding sites after the finding of a positive human, bird or animal. • Collecting and submitting samples for identification. • Larval identification class.

24. Mosquito Pupae “tumblers” trumpets

25. Adult emergence

26. Adult Surveillance • Assist with locating breeding sites after the finding of a positive human, bird or animal. • Assist with trapping adult mosquitoes for virus testing.

27. CO2 by gas cylinder CO2 supplied by dry ice CDC Gravid trap

30. 2004 Mosquito Surveillance • Continue larval collections around positive all arbovirus cases. • Collect and test adult mosquitoes around positive all arbovirus cases. • Test 1,000 mosquito pools at the Office of Laboratory Services.