Are coyotes contributing to the spread Rocky Mountain spotted fever in Arizona?

Methods

Summary

We will collect specimens using both lethal and non-lethal means. The lethal specimen collection methods will be opportunistic: we will take specimens from coyotes killed legally by hunters and state-sponsored culling operations.

The non-lethal specimen collection methods are preferable, and we will use a combination of approaches. First, we will set snares, which are considered to be relatively humane. The snares will be fitted with a variety of safety mechanisms, including swivels, deer stops, and breakaway devices. Additionally, each snare will have crushed diazepam-impregnated cotton attached, a technique that has been shown to calm snared coyotes and prevent self-inflicted injuries. Snares will be checked regularly, and snared coyotes will be chemically immobilized prior to being processed.

The second non-lethal approach we will use involves electronic predator callers. We will use these devices to call in coyotes and then chemically immobilize them using a pneumatic dart rifle.

Regardless of the method used to collect specimens, we will collect blood, a skin biopsy, and any ticks we find. Blood will be stored in either EDTA tubes or serum tubes depending on the collection method and quantity of blood. Both blood and skin samples will be kept frozen. Ectoparasites will be stored in 70% ethanol.

We will collaborate with the Nieto Lab at Northern Arizona University for the identification and diagnoses of all ticks and tissues. This lab has the expertise to test any ticks or tissues for Rickettsial DNA or antibodies.
http://www.nietolab.com

We will test all blood specimens for Rocky Mountain spotted fever antibodies using Immunofluorescence Assay (IFA) tests.

Any positive results on either PCR or IFA tests will give us precedent to seek funding for further PCR tests on the skin biopsies. If we find antibodies or Rickettsial DNA in any coyote blood or other tissues, we will also seek funding to study the movements of coyotes and map out the risk they present to the spread of RMSF to humans.

Challenges

The biggest challenges we face are that coyotes are extremely difficult to capture, and that we need large sample sizes from throughout Arizona. We will overcome the first challenge by using a variety of capture methods, as outlined in the methods summary above. As we gain additional experience using these methods with Arizona's coyote populations, we will learn which methods work most effectively and modify our approach as necessary.

The second major challenge is to obtain a large number of specimens from throughout Arizona. To facilitate success, we are cultivating relationships with various state governmental agencies and tribal organizations. Several of these entities have offered to assist in specimen collection in various ways.