fazd heartwater power point module final sept 2011

Heartwater: Risk to US Livestock and Wildlife

Christopher Hensley and Pete D. TeelSenior Forensic and Investigative Sciences & Psychology Double Major, 2012

And Professor and Associate Department HeadDepartment of Entomology

Texas A&M University

1

2

Overview

• General Information• Issue & Threat• Cattle Egret• Geographic Distribution• Impact• Conclusions

3

Heartwater: General Information

• African tick borne diseaseAffects ruminants (broad range of species)Not in US, but in Caribbean

• PathogenEhrlichia ruminantium

(Formerly Cowdria)

• Tick VectorsGenus Amblyomma

(12 species recognized)

4

Genus Amblyomma

• A. variegatum• Tropical Bont Tick• Spread to 14 Caribbean Islands

Other principle African vector species not in Western Hemisphere• A. hebraeum• A. gemma

5

Issue & Threat

• Risk of Heartwater to North America• Presence of primary vector and pathogen in Caribbean

• Discovery of native tick to be efficient experimental vector

• Role of cattle egrets as host and transport of

immature ticks

• Supportive climate

• Diversity of livestock andWildlife hosts in US

Potential Native Tick Vector

• The Gulf Coast tick, Amblyomma maculatum• Laboratory studies using a goat – tick model• Findings show A. maculatum very capable of

acquiring E. ruminantium from sub-clinical, infected goats. (See Mahan et al. 2000)

• Summation: A substantial risk as vector.• Vector capacity under field conditions not yet

tested.

6

7

Cattle Egret: Host & Transport

• Caribbean introductions1940-50’s• Now widespread in Western

Hemisphere• Nest throughout Caribbean• Host to immature Amblyomma ticks

8

Cattle Egret: Migratory Risk

• Migrate across Americas• Involved in inter-island travel• Caribbean birds found in Florida Keys

9

Geographic Distribution

• Heartwater and Amblyomma vectors are widespread in Africa south of the Sahara

• Caribbean introduction and spread– First reported 1830s (limited to 3 islands)– Tick expansion 1970s-1980s to 14 islands

10

Geographic Distribution

• Potential spread – North and South American mainlands

• Southeastern US at high risk– Close proximity– Suitable climate– Livestock density– Native and Exotic deer

11

Impact

• Highly fatal• Economic risks

– high cost for containment and elimination• No drugs or vaccines• Surveillance testing• Quarantine

12

Conclusions

•Vigilance to changes in Caribbean•Support efforts to Caribbean containment•Active surveillance of ticks from Texas to Florida and Georgia into National Tick Surveillance Program (USDA, APHIS, VS)•Contingency response at state & federal levels •Educate owners and veterinary professionals

13

Resources Available

http://www.anapsid.org/heartwater.html http://www.avianweb.com/cattleegrets.html http://www.cfsph.iastate.edu/DiseaseInfo/disease.php?name=heartwater http://www.cfsph.iastate.edu/DiseaseInfo/factsheets.php http://www.epi.ufl.edu/?q=node/34 http://www.uniprot.org/taxonomy/34610 http://www.vetmed.ucdavis.edu/vetext/INF-DA/INF-DA_HEARTWATER.HTML