NEWSLETTER ARTICLES
Livestock and Natural Resources

In the October 1998 edition of this newsletter I reported of the work by industry, the University of California, and the California Department of Food and Agriculture (CDFA) to control Trichomoniasis.

At the December California Cattlemen’s Association Convention, a resolution for a Trichomoniasis control program was passed by the membership. What does this resolution say and what will it mean? To answer these questions, Dr. John Maas, Extension Veterinarian from UC Davis, provided the following information:

1. The California Cattlemen’s Association (CCA), in cooperation with allied industry, the School of Veterinary Medicine, the University of California Cooperative Extension, and veterinarians from CDFA’s Animal Health Branch will develop a comprehensive educational program regarding Trichomoniasis control for cattle producers. This is the foundation of the control program! It was agreed at each step that an aggressive educational program was essential for a successful effort to reduce the amount of Trichomoniasis in California beef cattle.

2. CCA will develop uniform guidelines for the voluntary testing of bulls for Trichomoniasis at point of sale of bulls (salesyards/auctions, bull sales, private treaty, etc.). This feature states that the cattle industry will develop uniform methods for all aspects regarding the diagnosis of this disease in cattle. This will include methods for sampling bulls, transporting samples to the laboratory, acceptable laboratory media and procedures for growing the Trich organisms, laboratory methods to identify the Trich organisms, and acceptable methods for confirming the diagnosis. These methods will be based on the best scientific data available and will rely heavily on experts at the University of California School of Veterinary Medicine, including the California Veterinary Diagnostic Laboratory System.

This feature emphasizes education of veterinarians and diagnostic personnel with regard to the latest in scientific and medical information. This process will be driven by the cattle industry, which is an important concept throughout this resolution.

3. Testing for Trichomoniasis will be on a voluntary basis. There is no mandatory testing of bulls proposed in this resolution as there is with Trichomoniasis programs in western states such as Idaho. However, if there is a positive diagnosis made, this must be reported to the Animal Health Branch of the CDFA. This will make Trichomoniasis a reportable disease.

4. Veterinarians from CDFA’s Animal Health Branch will notify contact herds of positive test results in neighboring herds. This feature allows for notification that this disease has been diagnosed nearby. There will be no quarantine of the infected bulls or of the infected herd. The program relies on the voluntary efforts of the owner to clean up the problem.

5. Imported bulls must be tested negative for Trichomoniasis 30 days prior to shipment into or 14 days after arrival in California with the following exceptions: dairy bulls, bulls for non-breeding purposes (rodeos, etc.), bulls consigned for slaughter, bulls under a pasture to pasture permit, virgin bulls certified by the owner, bulls destined for artificial insemination premises, and bulls less than 18 months of age.

This feature makes imported bulls undergo mandatory testing for Trichomoniasis so that California will not become a "dumping ground" for infected bulls from other western states. There are many exceptions, so hopefully, free movement of clean, well-managed herds will not be restricted. This resolution does not address dairy cattle at all and will not interfere with that industry.

6. The Trichomoniasis Working Group will meet at least annually to review the Trichomoniasis Control Program with CDFA and report to CCA. This feature allows for continuous review of the program. It assures that the program is driven by and supervised by the cattle industry and allows changes to the program or elimination of the program if conditions warrant such actions.

It was further resolved that the CCA will work with CDFA to pursue the legislative authority and/or regulations to put this resolution into effect. This aspect will take some time and may have some surprises. However, there appears to be widespread support for this type of program in the cattle industry. The ideas and concepts were developed from the grassroots level and this will not be a mandatory program, with the exception of reporting of positive test results.

Have you ever heard of or seen beef measles? I hadn’t either until two years ago when I was collecting carcass information from steers from the county fair. One of these carcasses was railed out and retained due to measles. During our annual carcass meeting, we discussed much of the following, but this information is worth repeating due to ongoing food safety concerns over biological contamination of our food supply.

What is beef measles?

"Beef measles" is the visible damage to muscle tissue (meat) in the carcass at slaughter, caused by the larvae of a tapeworm. This tapeworm is sometimes referred to as the "beef tapeworm." However, cattle are not the host of this tapeworm, humans are. The organism, Taenia saginata, is a tapeworm that inhabits the small intestine of man, and the larva of this human tapeworm cause "measles" in beef.

How does this larva get into beef?

The tapeworm inhabits the small intestine of humans, more commonly in developing countries and only sporadically in the US and Canada. The tapeworm usually does not cause symptoms of disease in humans. It can grow to a length of more than 15 feet. This tapeworm has a long life span that usually is as long as the person it infects. Adult tapeworms release about 6 to 9 egg packets (proglottids) each day. Each of these egg packets contains 100,000 to 150,000 eggs. These egg packets are passed in the feces of the infected humans.

The eggs do not survive dry conditions very well, but they can survive in manure or moist pastures for 60 to 70 days at 75 degrees and 6 months at 40 degrees. When carrier humans defecate on pasture or in feeds consumed by cattle, the eggs can be ingested by the cattle. The eggs swallowed by cattle hatch in the small intestine. The larva penetrate the intestine and circulate throughout the animal's body. The larva mature to cysts, causing "measles" in the tissue of cattle. These cysts are about the size of a large pea and are easily seen in the muscle tissue. A "measley" carcass can contain thousands of these cysts that remain infective for about 2 years.

Carcasses identified to be severely affected are condemned. Other carcasses less severely affected must be processed by freezing (for 15 days) or by cooking, before being passed by inspectors. Can you imagine how the packer feels about this?

Can people catch measles from affected cattle?

No! The diseases in people we call measles are caused by viruses that are unique to humans and these viruses do not cross the species lines between cattle and man. However, the problem with measles in beef comes directly from humans and contamination of cattle feed or pastures by human feces. If humans eat undercooked beef with the cysts (measles), they can become infected with the tapeworm that could again generate the tapeworm eggs that cause measles in beef.

How do outbreaks of measles occur?

Large outbreaks may occur when the feed or pasture for cattle becomes contaminated with human feces. Use of raw sewage for fertilization on pastures or sewage contamination of irrigation water can account for large problems in this regard. Several thousand beef carcasses are found to contain these cysts each year in the US. The underlying cause in all cases is infective human excrement that finds its way into cattle feeds, grain silos, or onto pastures.

How can beef measles be prevented?

The bottom line is the elimination of human feces from pastures or feeds used for cattle production. Humans that are infected with the tapeworms can be identified by a number of diagnostic tests. There are safe and effective drugs for treatment of infected humans.

Preventing human feces from coming into contact with cattle feeds or pastures is central to the prevention of this problem. Use of human sewage as fertilizer or irrigation water cannot be routinely recommended because of the potential of this serious problem. The problem of measles in beef can be very complicated. The key to prevention lies in understanding the source and circumstances under which it can develop.

My thanks to Dr. John Maas, Extension Veterinarian, UC Davis, for the information in this article.