New Research Project: Serological Investigation of Cuterebra Larval Migration as a Cause of Neurologic Disease in Cats.

The Winn Feline Foundation has recently generously awarded a grant to the Mississippi State University College of Veterinary Medicine to investigate the role of migrating Cuterebra larvae in feline neurologic disease.

Researchers involved in the project include Dr. Andrew Mackin of the Animal Health Center and Drs. Lora Ballweber and Carla Siefker of the Parasitology service.

The project will be completed over the next eighteen months, and will rely heavily on collaboration between MSU, small animal general practitioners, and specialist neurologists across North America.

Background

Myiasis (infection of tissues by migrating fly larvae) in North American cats is most commonly caused by larvae from the Cuterebra species of fly. Although Cuterebra larvae typically burrow subcutaneously, aberrant migrations have occasionally been reported to involve the brain. Intracranial larval migration can cause severe neurologic signs, and most confirmed cases resulted in the death of the affected cat. Confirmation of myiasis as the cause of neurologic disease is usually based on the post-mortem finding of larvae in the brain. The establishment of a definitive diagnosis of intracranial larval migration without post-mortem is difficult.

Several acute neurologic conditions in the cat, such as feline ischemic encephalopathy and feline vestibular syndrome, currently have no single proven cause. The handful of confirmed cases of intracranial Cuterebra larval migration in cats have clinical and pathologic features that resemble these idiopathic acute neurologic disorders. Some neurologists therefore hypothesize that aberrant larval migration may be the major cause of these disorders. This hypothesis, although attractive, is difficult to prove because many cats survive these idiopathic neurologic disorders, and are therefore not available for necropsy.

The purpose of the new MSU study is to test the hypothesis that Cuterebra larval migration is an important cause of acute neurologic disease in the cat. We will develop an enzyme-linked immunoassay (ELISA) that detects antibodies against Cuterebra larvae. We will then compare the prevalence of antibodies against Cuterebra larvae within the general cat population to the prevalence of antibodies in cats with ischemic encephalopathy or vestibular syndrome.

How Can General Practitioners Help?

In many parts of the United States, subcutaneous Cuterebra larvae are a common problem affecting outdoor cats in the summer months. General practitioners are adept at recognizing this condition and then extracting the larvae through their breathing holes. These cases of feline cuterebriasis represent an excellent opportunity for us to study the typical antibody responses of affected cats to the migrating parasite. We are therefore actively seeking to collect serum samples and larvae from cats that are known to be affected with Cuterebra. The assistance of general practitioners in this endeavor will be of enormous benefit.

Project Details

Serum and larvae collected from cats with typical subcutaneous cuterebriasis will be used to develop and validate the serum ELISA designed to detect and quantitate antibodies against Cuterebra larvae, and to study the pattern and timing of antibody responses to this parasite.

What is needed:

Serum

1. Serum from any cat that is affected by subcutaneous Cuterebra larvae, collected at the time of parasite extraction and (when possible) again 2-4 weeks later.

2. Serum from any cat that is known to have suffered from subcutaneous cuterebriasis in the past two years.

Samples may be sent as clotted whole blood (at least 2 mls if possible) or as separated serum (at least 1 ml if possible). Serum samples may be frozen until submission details are coordinated.

Larvae

1. Larvae extracted from any affected cats.

Larvae should be frozen after extraction. We will then arrange transportation of the specimens (larval samples must remain frozen, and are therefore transported on dry ice).

Paired samples of both serum and larva from affected cats at the time of diagnosis and larval extraction are ideal. In order to off-set the costs and labor involved in sample collection and submission, practitioners will be reimbursed $20 for each set of serum and larval samples submitted to MSU.

* * * Your assistance in this study is greatly appreciated * *

Reviewed 5/3/04