Recent Trends in Arboviruses Found in the United States

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1 Recent Trends in Arboviruses Found in the United States Janet C. McAllister, Ph.D. Arboviral Diseases Branch Division of Vector-Borne Infectious Diseases Centers for Disease Control and Prevention The findings and conclusions in this presentation are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention

2 Topics Arboviruses of public health importance Current and historical epidemiology Other arboviruses of concern

3 Arbovirus Transmission Cycle Food, Space, Breeding sites Predators and Pathogens Virus Vertebrate Host Virus Weather and Climate Primary or Accessory Vector Incidental hosts Pupae Vector Adults Terrestrial Aquatic Larvae Eggs Weather and Climate Food, Space, Breeding sites

4 Arboviruses in the United States Selected representatives by Family Eastern Equine Enceph. Cache Valley San Angelo Buttonwillow Reed Ranch Venezuelan* Everglades Lokern Jamestown Canyon Turlock Muir Springs Western Equine Enceph. Northway Jerry Slough Potosi Malpais Spring Highlands J Tensaw South River Rio Grande Hart Park/Flanders Fort Morgan Main Drain Keystone Hughes Sawgrass St. Louis Enceph. Virgin River Trivittatus Bluetongue Kern Canyon Powassan Nepuyo Mahogany Hammock Enzootic Hemor. Dis. West Nile Gumbo Limbo Shark River Mono Lake Dengue* California Enceph. Pahayokee Colorado Tick Fever Yellow Fever* La Crosse Mermet Vesicular Stomatitis *not endemic Arbovirus Family: Togaviridae Flaviviridae Bunyaviridae Reoviridae Rhabdoviridae

5 WEST NILE Flavivirus Habitat Associations: Various urban, suburban, rural Vertebrate host: Birds Vectors: East: Cx. pipiens, Cx. quinquefasciatus West: Cx. tarsalis Florida: Cx. nigripalpus Numerous other species may be locally important during epidemic transmission

6 West Nile Virus Encephalitis Human cases: Human Cases Reported from 47 States

7 West Nile Virus Encephalitis Human Cases Reported 2009 N = 663

8 Number of Cases (log scale) West Nile Virus Total Cases in U.S Year Reported Human Cases Reported Average = 2692/yr; range =

9 ST. LOUIS ENCEPHALITIS Flavivirus Habitat Associations: Various, urban suburban, rural Vertebrate host - birds Vectors: East: Cx. pipiens, Cx. quinquefasciatus West: Cx. tarsalis Florida: Cx. nigripalpus

10 St. Louis Encephalitis Human cases: Human Cases Reported from 42 States

11 St. Louis Encephalitis Human Cases Reported 2009 N = 10

12 Number of Cases (log scale) St. Louis Encephalitis Total Cases in U.S Year Reported Human Cases Average = 102/yr; Range =

13 LA CROSSE Bunyavirus California Serogroup Habitat Associations: Hardwood Forests Vertebrate hosts:- Chipmunks, Squirrels Vectors Ae. triseriatus primary vector Ae. canadensis Ae. albopictus (suspected)

14 LaCrosse Encephalitis Human cases: Human Cases Reported from 26 States Historically not found

15 LaCrosse Encephalitis Human Cases Reported 2009 N= 37 Historically not found

16 Number of Cases La Crosse Encephalitis Total Cases in U.S Year Reported Human Cases Average = 78/year; Range =

17 WESTERN EQUINE ENCEPHALITIS Alphavirus Habitat Associations: Irrigated areas and river flood plains Vertebrate host - birds Vectors Cx. tarsalis Other mosquitoes?

18 Western Equine Encephalitis Human cases: Human Cases Reported from 21 States Historically not found

19 Western Equine Encephalitis Human Cases Reported 2009 N=0 Historically not found

20 Number of Cases Western Equine Encephalitis Total Cases in U.S Year Reported Human Cases Average = 14/year; Range = 0-172

21 EASTERN EQUINE ENCEPHALITIS Alphavirus Habitat Associations: Freshwater, hardwood swamps Vertebrate host - Birds Epizootic vector Cs. melanura Vectors to mammals Cq. perturbans Ae. vexans Ae. sollicitans Cx. nigripalpus

22 Eastern Equine Encephalitis Human cases: Human Cases Reported from 20 States Historically not found

23 Eastern Equine Encephalitis 307 Horse cases: 2009 Human Cases Reported 2009=4 Historically not found

24 Number of Cases Eastern Equine Encephalitis 25 Total Cases in U.S Year Reported Human Cases Average = 7/year; Range = 0-21

25 LAC <1* 7 20 Average WN WEE EEE SLE Year Arbovirus Cases Cases in U.S

26 Urban Yellow Fever Epidemics in the United States Currently: Rare imported cases with travel history No local transmission 1. Philadelphia, 1793; 5,000 dead 2. New York City, 1795; 730 dead 3. Boston, New York City and Philadelphia, 1798; more than 5,000 dead 4. Baltimore, 1800; 1,200 dead 5. New Orleans, 1853; 8000 or more dead 6. Norfolk, 1855; 2,000 dead 7. Mississippi Valley, 1878; 20,000 dead 8. Cuba, 1898; hundreds dead. 9. New Orleans, 1905; more than 900 dead

27 Cases of chikungunya fever (between ) have been reported in the countries depicted in red. In Africa, these include Burundi; Central African Republic; Comoros; Democratic Republic of Congo; Guinea; Kenya; Nigeria; Madagascar; Malawi; Mauritius; Mayotte; Reunion; Senegal; Seychelles, South Africa; Tanzania; Uganda; Zimbabwe. In Asia, these include Australia; Burma; Cambodia; India; Indonesia; Malaysia; Pakistan; Philippines; Taiwan; Thailand; Timor; Vietnam.

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29 Presence of the Asian tiger mosquito (Aedes albopictus) in provinces of Europe, as of January 2007 Source: Scholte E.-J. & Schaffner F., Waiting for the tiger: establishment and spread of the Aedes albopictus Mosquito in Europe. In Emerging pests and vector-borne disease in Europe (Takken W. & Knols B.G.J., Eds.), 2007, Wageningen Academic Publishers, Wageningen, The Netherlands, in press.

30 Geographic distribution of Japanese encephalitis.

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32 1997/ / / Dengue Travelers Local Transmission

33 Dengue Human cases: 2009 Human Cases Reported from 14 States

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