Are You at Risk for Antibiotic Resistance?

Bison Outside Yellowstone National Park

Though bison are well-suited for the harsh climate of Yellowstone National Park, the winters from 1995 to 1997 were particularly severe in the high country, forcing bison to leave the park in search of food. They found milder conditions and convenient grazing on several U.S. Forest Service allotments that were used by area cattle ranching families in the summer.

In 1995, the Yellowstone bison herd was designated by the Montana state legislature as a species in need of disease management, as some bison carry brucellosis.

The Montana state legislature then designated the Deparment of Livestock (DOL) to be the lead agency for the bison/brucellosis disease management outside of Yellowstone. It was the DOL's responsibility to work with other state and federal agencies either to force the bison leaving Yellowstone National Park back within park boundaries or to capture and test for brucellosis those bison that could not be moved back into the park. The DOL's role in bison management has been problematic for environmental groups who believe that wildlife officials, not a livestock agency, should be managing bison.

Brucellosis

Ranchers are nervous about mingling between cattle and bison because of brucellosis, which can decrease milk production and animal weight, cause spontaneous abortion of the animal's first fetus and cause infertility. For nearly 60 years and at a cost of billions of dollars, the livestock industry across the United States has waged a war to eliminate brucellosis from its herds. In 1952, the U.S. Department of Agriculture (USDA) estimated that annual losses due to this disease were more than $400 million. To prevent an epidemic of the disease, federal and state agriculture officials have eliminated infected herds.

Brucellosis can also infect human beings, causing persistent, intermittent flu-like symptoms known as undulant fever. Transmission occurs through direct contact between a person's open cuts and birthing fluids or animal tissue. Veterinarians, butchers and farmers have been those most commonly affected, though the incidence of brucellosis in humans is extremely rare.

Brucellosis was first identified in domestic cattle in the United States in 1910. In 1917, it was first identified in Yellowstone bison.

The USDA, responding to livestock and public health concerns, began an effort to control and eradicate brucellosis in 1934 by developing vaccines and depopulating entire herds when several animals tested positive for the bacterium. Currently, all but Florida and South Dakota are brucellosis-free, and these last two states are poised to eradicate the disease.

After more than 30 years and $30 million, and the sacrifice of many cattle, Montana achieved brucellosis-free status in 1985. That same year, state and federal agencies began eliminating some Yellowstone bison that migrated out of park boundaries. Since the winter of 1991-92, Native Americans from reservations such as northern Cheyenne, Crow, and Fort Peck have sometimes assisted in harvesting and using the bison carcasses. Other bison carcasses have been distributed to nonprofit charitable organizations and food banks.

A scientific dispute

Yellowstone's bison herd carries an uncontrolled pocket of the disease. However, detractors of the slaughter believe there are flaws in the bison management:

Bison migrate out of the park to graze in the winter and spring, whereas cattle are not placed on the allotments until June, after most bison have gone back over the park border. However, there is disagreement about how long the Brucella bacteria can survive in the environment. As a precaution, cattle and bison are kept from interacting for at least 45 days.

Transmission occurs mainly through direct contact with birthing matter, but state and federal officials have included hundreds of male bison in their slaughter, contending that males still present a risk.

Methods of testing for brucellosis are hardly foolproof. Among those bison who field-tested positive for brucellosis and were killed between 1996 and 1999, 80 percent later tested negative for the disease in more reliable lab tests.

Thousands of elk in the region also carry the disease, but are not managed similarly.

There has been no documented case of brucellosis transmission in the wild between cattle and bison. Known transmission has only occurred in the lab.

Today, some tribes and Native groups are trying to reintroduce bison onto their reservations. They are also working to take in unwanted bison from Yellowstone instead of having these animals sent to slaughter. So far, these requests have been denied by government officials.

A Bird Flu Outbreak Is Spreading Among Cows In The US. Scientists Are Hunting For Answers

At first glance, it looks like an unassuming farm. Cows are scattered across fenced-in fields. A milking barn sits in the distance with a tractor parked alongside. But the people who work there are not farmers, and other buildings look more like what you'd find at a modern university than in a cow pasture.

Welcome to the National Animal Disease Center, a government research facility in Iowa where 43 scientists work with pigs, cows and other animals, pushing to solve the bird flu outbreak currently spreading through U.S. Animals — and develop ways to stop it.

Particularly important is the testing of a cow vaccine designed to stop the continued spread of the virus — thereby, hopefully, reducing the risk that it will someday become a widespread disease in people.

The U.S. Department of Agriculture facility opened in 1961 in Ames, a college town about 45 minutes north of Des Moines. The center is located on a pastoral, 523-acre (212-hectare) site a couple of miles east of Ames' low-slung downtown.

It's a quiet place with a rich history. Through the years, researchers there developed vaccines against various diseases that endanger pigs and cattle, including hog cholera and brucellosis. And work there during the H1N1 flu pandemic in 2009 — known at the time as "swine flu" — proved the virus was confined to the respiratory tract of pigs and that pork was safe to eat.

The center has the unusual resources and experience to do that kind of work, said Richard Webby, a prominent flu researcher at St. Jude Children's Research Hospital in Memphis.

"That's not a capacity that many places in the U.S. Have," said Webby, who has been collaborating with the Ames facility on the cow vaccine work.

The campus has 93 buildings, including a high-containment laboratory building whose exterior is reminiscent of a modern megachurch but inside features a series of compartmentalized corridors and rooms, some containing infected animals. That's where scientists work with more dangerous germs, including the H5N1 bird flu. There's also a building with three floors of offices that houses animal disease researchers as well as a testing center that is a "for animals" version of the CDC labs in Atlanta that identify rare (and sometimes scary) new human infections.

About 660 people work at the campus — roughly a third of them assigned to the animal disease center, which has a $38 million annual budget. They were already busy with a wide range of projects but grew even busier this year after the H5N1 bird flu unexpectedly jumped into U.S. Dairy cows.

"It's just amazing how people just dig down and make it work," said Mark Ackermann, the center's director.

The virus was first identified in 1959 and grew into a widespread and highly lethal menace to migratory birds and domesticated poultry. Meanwhile, the virus evolved, and in the past few years has been detected in a growing number of animals ranging from dogs and cats to sea lions and polar bears.

Despite the spread in different animals, scientists were still surprised this year when infections were suddenly detected in cows — specifically, in the udders and milk of dairy cows. It's not unusual for bacteria to cause udder infections, but a flu virus?

"Typically we think of influenza as being a respiratory disease," said Kaitlyn Sarlo Davila, a researcher at the Ames facility.

Much of the research on the disease has been conducted at a USDA poultry research center in Athens, Georgia, but the appearance of the virus in cows pulled the Ames center into the mix.

Amy Baker, a researcher who has won awards for her research on flu in pigs, is now testing a vaccine for cows. Preliminary results are expected soon, she said.

USDA spokesperson Shilo Weir called the work promising but early in development. There is not yet an approved bird flu vaccine being used at U.S. Poultry farms, and Weir said that while poultry vaccines are being pursued, any such strategy would be challenging and would not be guaranteed to eliminate the virus.

Baker and other researchers also have been working on studies in which they try to see how the virus spreads between cows. That work is going on in the high-containment building, where scientists and animal caretakers don specialized respirators and other protective equipment.

The research exposed four yearling heifers to a virus-carrying mist and then squirted the virus into the teats and udders of two lactating cows. The first four cows got infected but had few symptoms. The second two got sicker — suffering diminished appetite, a drop in milk production and producing thick, yellowish milk.

The conclusion that the virus mainly spreads through exposure to milk containing high levels of the virus — which could then spread through shared milking equipment or other means — was consistent with what health investigators understood to be going on. But it was important to do the work because it has sometimes been difficult to get complete information from dairy farms, Webby said.

"At best we had some good hunches about how the virus was circulating, but we didn't really know," he added.

USDA scientists are doing additional work, checking the blood of calves that drank raw milk for signs of infection.

A study conducted by the Iowa center and several universities concluded that the virus was likely circulating for months before it was officially reported in Texas in March.

The study also noted a new and rare combination of genes in the bird flu virus that spilled over into the cows, and researchers are sorting out whether that enabled it to spread to cows, or among cows, said Tavis Anderson, who helped lead the work.

Either way, the researchers in Ames expect to be busy for years.

"Do they (cows) have their own unique influenzas? Can it go from a cow back into wild birds? Can it go from a cow into a human? Cow into a pig?" Anderson added. "Understanding those dynamics, I think, is the outstanding research question — or one of them."

___

Stobbe reported from New York.

DeFraites Study

I. EXECUTIVE SUMMARY

In early spring 1992, 125 veterans of Operation Desert Shield/Storm (ODS/S) assigned to the 123d Army Reserve Command (ARCOM) reported a wide variety of non-specific symptoms including fatigue, joint pains, skin rashes, headaches, loss of memeory, mood changes, diarrhea, bleeding and painful gums, and loss of hair. Most of these symptoms were first noticed after the soldiers returned home after the deployment to southwest (SW) Asia. Although several had been medically evaluated, no unifying diagnosis, other than a suspected reaction to stress had emerged. On 11-12 April, seventy-nine 123d ARCOM soldiers with symptoms or concerns were evaluated by a multidisciplinary medical team. Each soldier completed a medical questionnaire and a brief symptom inventory, and was interviewed by an epidemiologist, an occupational medicine physician and a psychiatrist. All were examined by an oral pathologist and had blood drawn for laboratory testing. There was no evidnce of an outbreak or cluster of any unique disease process. Very few soldiers gave histories that suggested any known hazardous exposures. Because of the wide variety of experiences during the deployment, ther ewere very few exposures common to the entire group. Reported symptoms did not correspond with known health effects of those exposures. Positive objective findings on physical examination and laboratory screening testing wre very limited, and were similar to those found in soldiers from Fort Lewis, WA, and Fort Bragg, NC, who were not deployed to SW Asia. Dental examination revealed gingivitis, periodontal disease, caries, and other chronic oral conditions as likely causes for the dental symptoms. Results of specific testing for leishmaniasis, brucellosis, and other agents indicated no role for them in causing the symptoms reported by this group. Although no confirmed pathogens have yet been isolated from those soldiers with diarrhea, some chronic diarrhea could conceivably have been related to the deployment and may require additional evaluation. The paucity of abnormal physical or laboratory findings, the types of symptoms reported, the association of onset of the symptoms with redeployment, and results of the psychiatric evaluation suggest that many of the symptoms are likely to be stress-related. These may represent a stress reaction to redeployment and subsequent readjustment to civilian life. Additional medical evaluation of these soldiers is indicated only on an individual basis. Stress management intervention with full command support is warranted. Additional epidemiological evaluation may be necessary, but only if specific diagnosable medical conditions emerge from this group.

IX. SUMMARY OF MAJOR FINDINGS AND CONCLUSIONS

Following screening of 79 soldiers of the 123d ARCOM and extensive medical evaluation of six, no single diagnosis or medical cause has emereged which can account for the majority if the reported symptoms.

Ruled out as major factors: Leishmaniasis (All 78 screened, two possible positive), brucellosis (none positive out of six with the most prominent symptoms tested), Lyme disease (non positive out of two with joint pains as major complaint tested), hypothyroidism (none positive out of five tested)

The evaluation of 79 soldiers on 11-12 April can be summarized as follows:

Subjective findings.

Fatigue was most common (70%) symptom. Other systemic symptoms like feversihness, abdominal pain, and diarrhea were much less common.

One typical pattern for these symptoms was the onset of fatigue and associated symptoms (memory loss, sleep disturbance, etc.) afer redeployment from SW Asia. There was one exception to this trend: diarrhea with onset during the deployment was slightly more common than reported with other symptoms.

Morbidity and disability associated with these symptoms were low.

Musculoskeletal injury, (or recovery from elective surgery) was the largest single medical cause of lost time from work/duty/school: 59.7% of total sick days during deployment, 43.8% since returning home.

There has been a low number of lost work days due to all non-injury illnesses since returning from SW Asia: 45.6% of soldiers interviewed reported no loss of work due to any non-injury illness, and 85% have lost 10 days or less. Six individuals (7.6%) accounted for 48% of all work days lost due to illness since redeployment.

We found no association between most individual symptoms (or groups of symptoms) and lost time from work due to illness. Exceptions of this were soldiers with abdominal pain and irritability (mood changes).

Objective findings

Reported hair loss by 21.5% was manifested primarily as diffuse thinning of the hair.

Skin rashes were representative of dermatological conditions found in general population.

Oral and dental complaints stem from poor preventive care and suboptimal hygienic practices over years. There was abundant objective evidence of chronic neglect of teeth.

The proportion of 123d ARCOM soldiers with elevated blood pressure (15%), elevated liver enzyme (ALT) (11.5%), or low hermatocrit (6.4%) was not markedly different that that of comparison populations of healthy active duty soldiers not deployed to SW Asia.

Enteric parasites were not ruled out: Chronic persistent diarrhea may require additional individual evaluation to make diagnosis.

Specific exposures

There was no association of anthrax vaccine, nerve agent antidote, or malaria pills with any symptom or lost work days.

We have no evidence that hazardous exposures to microwaves, chemicals, or radiation occurred. The types and pattern of the symptoms reported and available objective evidence also do not support any link with these exposures.

Measures of stress were the most striking positive findings of our evaluation. These soldiers reported very high levels of stress, to which many of the subjective symptoms, and some of the objective ones, such as high blood pressure and loss of hair amy be attributable. Post-traumatic stress disorder, on the other hand, seemed to be present in a very few of these soldiers.

CONCLUSIONS

There is at present no objective evidence to suggest an outbreak of any disease in 123d ARCOM. We feel that the documentable medical problems and illnesses found in this group are typical of what one would expect in the general population.

Musculoskeletal injuries and their sequelae were the most important medical problems experienced by this group, during and since the deployment.

Stress associated with post-deployment adjustment to civilian life is a plausible etiology for the many of the symptoms reported, especially sleep disturbances, depression, forgetfulness, and cognitive difficulties. In general, these symptoms have been worrisome, but not debilitating.

Association of any illness, injury, or symptom with the deployment must be made on an individual basis. In this group, the only problems which seem directly related to the deployment were some of the injuries. To date we have found no objective evidence of disease which could be proven to be related directly to deployment to SW Asia.

Chronic or persistent diarrhea may be associated with the deployment, although no specific agent has been identified. However, diarrhea and other gastrointestinal symptoms with onset now or in the future are much less likely to related to known enteric pathogens from SW Asia.

---