Got Tonsil?

June 21, 2006 — 

No diagnostic sample submission is complete without including the tonsil. Because of their location in the oropharynx, the tonsils are exposed to a variety of viral and bacterial pathogens. Advances in diagnostic capabilities have made analysis of the tonsils an increasingly important tool in the diagnosis of a number of endemic swine diseases. USDA, APHIS now has funding to use the tonsil as part of a routine surveillance program to detect Classical Swine Fever (CSF) and is offering incentives to encourage practitioners to submit samples for surveillance.

Tests using the tonsil have been developed by the Foreign Animal Disease Diagnostic Laboratory at the USDA's Plum Island Animal Disease Center to aid in the detection and diagnosis of CSF. The USDA's Manual for Classical Swine Fever Surveillance, includes tonsil, tonsil scrapings and nasal swabs as appropriate samples for CSF detection if collected and submitted properly. Submission of tonsil scrapings and nasal swabs requires a special transport media, Dulbecco's Modified Eagle Medium (DMEM), which is available from the National Veterinary Services Laboratory (NVSL) in Ames, IA. As an incentive for producers and veterinarians to submit tonsils USDA will credit the submitter with $50 to be applied to the diagnostic workup for those cases tested by one of the following National Animal Health Laboratory Network (NAHLN) laboratories: Florida, Georgia, New York, North Carolina, Arizona, California, Iowa, Texas, and Washington.

USDA has designated 18 states and Puerto Rico as "high risk" for CSF introduction. The designated high risk states for CSF introduction are as follows: Florida, Arizona, Georgia, California, Illinois, Hawaii, Indiana, Iowa, Minnesota, Kansas, New Jersey, Nebraska, New York, New Mexico, North Carolina, Oklahoma, Texas, and Washington Surveillance efforts will focus on these locations. With the exception of Iowa and Minnesota, all tonsil and nasal swab samples sent to a participating NAHLN laboratory in or from these states are eligible to be tested.

Due to the large number of swine cases submitted to the NAHLN diagnostic labs in Minnesota and Iowa, samples from these states will be eligible for testing if at least one of the following lesions is observed:

• dramatic acute septicemias,
• abortions, congenital deformities,
• dermatitis or nephritis (PDNS),
• undiagnosed CNS cases or
• other undefined cases the pathologist wishes to submit.

In cases where, based on history, clinical signs, or other indicators, the veterinarian actually suspects that CSF could have infected the herd then the veterinarian should immediately call the State Veterinarian or USDA Area Veterinarian in Charge to request a foreign animal disease investigation with submission of diagnostic samples to the Foreign Animal Disease Diagnostic Laboratory.

For a complete description of sample collection and submission techniques, please visit the USDA's CSF surveillance website or contact the program managers at USDA-APHIS-VS-NAHPS, David Pyburn (515-284-4122 or David.G.Pyburn@aphis.usda.gov) or John Korslund (301-734-5914 or John.A.Korslund@aphis.usda.gov), or to FADDL (631-323-3256 or samia.a.metwally@aphis.usda.gov).