Hoof and mouth disease

by Mary Kasulaitis

We’ve heard this before and we’ll hear it again. Cattle being slaughtered by the thousands to prevent the spread of hoof and mouth disease. Scientifically known as aftosa, it is also commonly called foot and mouth disease. All animals with cloven hoofs are susceptible: cattle, sheep, pigs, goats and deer. Hoof and mouth disease does not hurt the meat of the infected animals and it does not affect humans. The illness produces a fever and blisters and lesions on the feet (between the toes) and in the mouth. Females may abort or develop chronic mastitis, thus both the meat and dairy industries are affected. There are several types and subtypes of the virus, each of which would require a different vaccine, thus making it difficult to control. Frequent revaccination is also necessary. Animals can recover, but while the disease runs its course the animals are miserable and weight loss occur since the animals don’t want to eat. The active symptoms, which includes lameness, may last a month. The mortality rate for young animals is high, but lower for adult animals. Therein lies the issue: to livestock and milk producers this disease can be devastating. It’s all about international economics. Originally surfacing in Europe two hundred years ago, the disease spread to Latin America where it still resides. A devastating outbreak of the virus started in England in February, 2001, and spread to France. Who knows how it got to England?

Aftosa is probably the most infectious illness in the world, and can be spread on the soles of shoes, by hand, car tires, and by the wind over distances as much as 40 miles. Imagine an international traveler, staying at a cute B & B on a farm in England, walking around the barn, hiking through the fields, and then coming home to his ranch in Southern Arizona without disinfecting his shoes. When we visited Scotland in 1999, the sign at U.S. Customs said anyone who visited an agricultural area in a foreign country should walk through a disinfecting agent to clean their shoes. But we didn’t have to, they said, so we didn’t. However, after a trip to Ireland in 2014 where we visited a farm, we spent time waiting for the Agricultural officer at the airport to check our shoes, and came close to missing the flight home. If aftosa had been incognito on that farm, we could have brought it home. And what about the shoes we had in our suitcases? No disinfecting there. This doesn’t seem to be an effective deterrent to halting the spread of a disease that has caused the deaths of millions of animals worldwide over the years.

One of the significant outbreaks of aftosa in the United States happened in California and Texas from February through July of 1924 with such repercussions that ever after measures were taken to protect the country from this disease. Governor Hunt of Arizona took steps to protect the state and banned the importation of all animals and any kind of food. That included dogs and cats. Ruthless enforcement by inspectors at the quarantine stations on the California border caused such a backup of travelers that an angry crowd tried to storm the bridge over the river at Yuma. The Fire Dept responded by dousing them with Colorado River water, which effectively turned them back. Another outbreak happened in Texas in that same year. Several influential ranchers had herds that had to be destroyed, so when hoof and mouth disease surfaced in Central Mexico in 1946, the U.S. government took drastic measures to prevent its spread to this country, and were successful.

Slaughtering the afflicted animals is the only known way of containing the disease, and since the Mexican government was not able to handle the outbreak by itself, the U.S. government decided to put up the money. A joint Mexican-American commission was set up in January, 1947. The U.S. would support enforcement and pay each and every owner for the cattle that had to be destroyed. Mexico would pay for the other kinds of animals. Kel M. Fox recounted an unforeseen complication: In those days, oxen were used by many of the small farmers. The U.S. provided mules (unaffected by the disease) to replace them, but in the meantime, thousands of small farmers with no income came to the U.S. looking for work. When the mules arrived, it appears that they walked too fast and tended to break the wooden plows that the farmers used. This meant the U.S. government had to provide steel plows. And so on…

The program consisted of a number of teams that went out into the Mexican countryside and looked for animals. The team would include an American Inspector, a Mexican Inspector, perhaps a veterinarian and soldiers to back them up. Jim Kelso, a resident of Arivaca back in the 1920s, remembered his days as an Inspector: they would go out into the small villages and look at the cattle, pigs and sheep. If they looked healthy, the team would vaccinate. If the animals had the disease, they were taken out, shot (this is known as the sanitary rifle), and burned with the remains buried in a pit. Needless to say, the farmers were not happy, but they were repaid. (As if that matters when the animal is like part of your family.) Jim remembered a woman who had a large sow. On the first visit, she refused to let the Inspectors come in, fearing the worst, so the soldiers had be called. The sow, which was hugely pregnant, had no sign of the disease, so she was vaccinated. Some time later, they returned to reinspect and were warmly greeted at the door by the woman. “Come in, come in!” she said. “Please vaccinate my pig again!” It turns out the pig had had twelve piglets. (It had never had more than two before.)

Other inspectors were not so fortunate. As the farmers across Mexico began to realize the ramifications of this governmental action, they began to resist. Mobs sometimes greeted the Inspectors and in one case, the whole team, including a large number of soldiers, was killed by angry campesinos. Another incident involved a young man from a local Southern Arizona ranch family. Robert Proctor took a year off from college to go to Mexico to work as an Inspector in 1948. As told by his brother, George (who had also been an inspector), he had been there almost a year and was about to return to the U.S. when he was sent to a small town along with a Mexican inspector, three soldiers and a guide. A mob of several hundred men and women appeared and attacked with stones and clubs. Robert attempted to get away but was beaten to death and his body buried. Later, his body was recovered and returned to his family in Arizona. George believes that this incident could have been predicted by the authorities and prevented, but for political reasons, no one was held accountable in Robert’s death. After that, a call for protection of American inspectors was raised.

It took four years, but the aftosa outbreak in Mexico was finally stemmed by the program. Procedures to maintain the health of livestock include separation of imported livestock. Line riders were hired to patrol the (frequently unfenced) Mexican border, even though the outbreak was two hundred and fifty miles south of here. One of those was Don Matheson, who lived in Arivaca, Ruby, Tres Bellotas and Sasabe during his tenure as a line rider. His job was to prevent the transportation across the international boundary of cattle that had not been quarantined for the allotted period to determine if they did or did not have the disease. He would ride the steep hills along the border between Sasabe and Bear Valley, looking for sign of cattle movement. You can imagine the difficulties. Better (?) fences were also constructed during this period. This is also just one of the U.S-Mexican issues that have formed the relationship between the two countries, and one that should not be forgotten by people on this side of the line.

As we have seen, hoof and mouth disease has not gone the way of smallpox. It is one of those elusive diseases that seem to get around all attempts at eradication. Keeping it at bay is a matter of constant vigilance. Perhaps that will be what happens with Covid19. At this point, who can say?


Manuel A. Machado, Jr. Aftosa: a historical survey of foot-and-mouth disease and inter-American relations.
Kel M. Fox, “Aftosa: the campaign against foot-and-mouth disease in Mexico, 1946-51,” The Journal of Arizona History, Spring, 1997, p. 23.

George Proctor, “An American tragedy in Mexico: the death of Robert Proctor,” The Journal of Arizona History, vol. 38, no. 4, p. 395.

Margaret Maxwell, “’It’s a dirty job, but somebody has to do it:’ Arizona’s little war of ‘24”
Thanks to Dr. Ted Noon and Don Matheson.

For more information on aftosa see this web page: https://www.aphis.usda.gov/publications/animal_health/2013/fs_fmd_general.pdf

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