West Virginia Veterinary Tick Submission Project: A Simple, Inexpensive Model for Tick and Tickborne Disease Surveillance

BACKGROUND:  From 2012 to 2013, probable and confirmed tickborne disease cases reported in West Virginia (WV) increased by 57.4%, from 101 to 159 cases. In 2013, the WV Bureau for Public Health launched the WV Veterinary Tick Submission Project (WVVTSP) to gain understanding about the local distribution of tick vectors associated with human tickborne diseases. Twenty-seven veterinary practices submitted 604 tick specimens from animal clients.  For 2014, pathogen testing of 2013 tick specimens was initiated, and new strategies were implemented to increase voluntary participation by veterinarians in tick surveillance efforts.

METHODS: Real-time PCR pathogen testing of 120 Ixodes scapularis ticks collected in 2013 was done at the Cornell University Animal Health Diagnostic Center for identification of Anaplasma sp., Babesia sp., and Borrelia burgdorferi. Recruitment packets containing a participation request letter, tick submission forms, postage-paid envelopes, and zoonotic disease information sheets were sent to 150 veterinary practices in January 2014. Participating veterinarians mailed ticks in postage-paid envelopes to the public health entomologist for identification.  Information collected on submission forms included date of tick collection, tick host species, home zip code of host, and information about IDEXX SNAP® 4Dx® Plus pathogen testing for dogs.

RESULTS: All I. scapularis ticks collected in 2013 were negative for pathogens. Veterinarians from 35 practices submitted 1,246 tick specimens in 2014.  Ticks were collected from hosts every month except February. Animal hosts included cats, dogs, humans, rabbits, a chipmunk, a fox, and a horse.  Six tick species were identified: Amblyomma americanum, Amblyomma maculatum, Dermacentor variabilis, Haemaphysalis leporispalustris, Ixodes cookei, and Ixodes scapularis. Of WV’s 55 counties, 41 (74.5%) were represented based on the home county of the host (in addition to 7 counties in Maryland, Ohio, Pennsylvania, and Virginia). I. scapularis was identified in 24 WV counties, 12 of which had human Lyme disease cases reported in 2014. Fifteen dogs tested positive for Borrelia burgdorferi by SNAP® 4Dx® Plus testing.

CONCLUSIONS: WVVTSP can be used as a model for states or regions with limited manpower and funding due to its simple and inexpensive methodology.  Upon defraying shipping costs, tick submissions more than doubled from 2013 to 2014. Zip codes of animal hosts will serve as future sites for active tick surveillance. More comprehensive pathogen testing will be initiated in 2015, prioritizing testing of tick specimens from areas with reported human tickborne disease activity. Veterinary tick submissions are useful for identifying tick populations and associated pathogens in a given area.