UC Agricultural Health & Safety Center at Davis
AgHealthNews
Issue Number 2000-03
Fall 2000
Published by the UC Agricultural Health & Safety Center at Davis,
University of California, Davis, Marc Schenker, M.D., M.P.H., Director,
Produced by EditPros, Davis, CA
2000-03-01 TABLE OF CONTENTS
- 2000-03-01 Table of Contents
- 2000-03-02 Welcome and Introduction
- 2000-03-03 Tuberculosis--the scourge of the
ages
- 2000-03-04 Water for the people in the field
- 2000-03-05 NIOSH recommends protection for workers
exposed to Class B biosolids
2000-03-02 WELCOME AND INTRODUCTION
Welcome to the UC Agricultural Health & Safety Center at Davis AgHealthNews.
AgHealthNews is an electronic version of the Center's quarterly
newsletter. The Center has two electronic list servers that allow
automatic forwarding of e-mail to a list of subscribers. One server
is a forum for announcements and discussion of agricultural health
and safety issues and the other is a vehicle for the automatic distribution
of the Center's quarterly newsletter.
The e-mail addresses for the forum is: aghealth@epm.ucdavis.edu
(message forwarding address) and aghealth-request@epm.ucdavis.edu
(subscriber request address). The addresses for the newsletter are:
aghealthnews@oem.ucdavis.edu (message forwarding address) and aghealthnews-request@oem.ucdavis.edu
(subscriber request address).
To subscribe to a list, send an e-mail message to the request
address with no subject and a one line message giving the option
subscribe and your name. For example, to subscribe to the forum
for announcements and general agricultural health and safety issues,
you would send the following: To: aghealth-request@epm.ucdavis.edu
Subject: Message: subscribe (your name here)
By return e-mail you will receive confirmation of your request
and more information about using the list server request functions.
To subscribe to the On-line News, your request would look like:
To: aghealthnews-request@oem.ucdavis.edu Subject: Message: subscribe
(your name here)
2000-03-03 TUBERCULOSIS--THE SCOURGE OF THE AGES
Estimates indicate that one-third of the world's population is infected
by Mycobacterium tuberculosis, leading to tuberculosis (TB) disease
that causes approximately 6 percent of all deaths. Stephen McCurdy,
M.D., M.P.H., associate professor in the School of Medicine Department of Epidemiology and Preventive Medicine, has suggested that the increased
prevalence of TB that occurred during the mid-'80s could be attributable
to two factors: 1) the HIV epidemic, and 2) a systematic disinvestment
in the public health structure. Groups at highest risk for tuberculosis
in the United States include HIV-infected persons, immigrants from
endemic areas who bring the disease with them, the homeless, and migrant
farmworkers. Some individuals exhibit all four of these risk characteristics.
"Roughly 2 million hired farmworkers nationwide are in crop production-900,000
are migrant seasonal workers and two-thirds of those are shuttle
migrants, meaning they have a home base in Mexico and they shuttle
up north where they have arranged employment. About 300,000 follow
the crops, and they represent a real challenge for TB control,"
said McCurdy.
During his talk titled "Tuberculosis and Other Respiratory Infections
Among Agricultural Workers" at the Center's noon seminar in June,
McCurdy cited a drop in tuberculosis (TB) cases in the United States
from 22,000 in 1995 to 17,528 in 1999.
"Looking back over the past century and a half, we see a clear
long-term trend toward lower risk and fewer cases of tuberculosis,
beginning well before the advent of effective antibiotics. The most
important determinant for a person's risk of tuberculosis is socioeconomic
status," said McCurdy.
"Improvement in socioeconomic and sanitary conditions has contributed
to a general downward trend in incidence of tuberculosis."
People who have a positive reaction to a TB skin test are often
confused and misinformed about TB disease versus TB infection. McCurdy
explained that active TB disease is an ongoing, advancing infection
usually in the lungs, but it can involve virtually any part of the
body. Symptoms can include fever, loss of weight and a bloody cough.
Untreated, TB disease is often fatal. However, TB infection results
from inhaling Mycobacterium tuberculosis, which establishes an infection
that the immune system of a healthy host holds in check. McCurdy
said, "People with TB infection usually live normal lives without
ever developing the deadly disease."
McCurdy conducted a study of Northern California migrant workers
in collaboration with Internal Medicine resident Desiree Arretz,
M.D. and Yolo County Health Officer Robert Bates. Researchers decided
that a social event would be the most effective method for involving
the largest number of individuals, and organized health fairs at
two Yolo County migrant worker housing camps. "A total of 469 persons
completed the questionnaire, which was about 70 percent of eligible
individuals, and we placed a total of 296 PPDs, which was 44 percent
of the participants," said McCurdy. He indicated that somewhat fewer
than 17 percent of the study participants showed positive TB skin
tests. This is somewhat higher than the general U.S. population,
but far less than the prevalence of positive tests found in the
East Coast region.
"So we've identified an increased risk in this group, and where
do we go from here?" McCurdy asked rhetorically. "We need to be
aware of what's going on with farmworkers, not only for their sake
but for our own self-interest as well. It's enlightened self-interest
to have an infrastructure in place that can take care of this."
The Migrant Clinicians Network in collaboration with the Centers
for Disease Control has established TBnet, a network to help take
care of farmworkers who develop TB or need prophylaxis. Since farmworkers
often migrate in pursuit of work, this network is designed to help
them find treatment at their next destination.
McCurdy received funding from the Wellness Foundation, as well
as assistance from the Chicano Medical Student Association and medical
residents. The UC Davis Medical Center donated supplies. For more
information on the study, contact McCurdy by phone at (530) 752-8051
or by e-mail at samccurdy@ucdavis.edu.
2000-03-04 WATER FOR THE PEOPLE IN THE FIELD
Water is just as essential to the people in the fields as it is to
sustain growth of the plants they are nurturing and harvesting. Hundreds
of thousands of agricultural workers in California perform strenuous
tasks in hot, dry weather, and our knowledge of how adequately hydrated
they are, what influences their actual fluid intake, and the personal
and performance consequences that may result from insufficient fluid
replacement is the focus of research begun last year by Howard Rosenberg,
Ph.D., a Cooperative Extension labor management specialist with the
Department of Agricultural and Resource Economics at UC Berkeley.
In May, Rosenberg discussed the details of two preliminary field studies
during a noon seminar titled "Improving Hydration to Combat Heat Stress
in Agricultural Work," sponsored by the Center.
Rosenberg explained, "The term `heat stress' refers to a group
of heat-related illnesses in which the body has an elevated core
temperature, symptoms of which can range from general discomfort
to heat stroke. Heat stroke is a potentially fatal emergency in
which temperature rises rapidly and the body's thermoregulatory
mechanisms cease to function. It may occur suddenly if heat exhaustion,
an intermediate but itself quite serious condition, is ignored."
Symptoms of heat exhaustion include fatigue, headache, dizziness,
muscle weakness, nausea, chills, tingling of hands or feet, confusion,
loss of coordination, fainting and collapse. "Critical to warding
off or recovering from these as well as less severe forms of heat
stress is keeping the body well hydrated," Rosenberg noted, "especially
replacing the fluid lost through sweating."
In February 1999 Rosenberg embarked on a round of informal observations,
reconnaissance, and discussion of these issues with farm advisor
colleagues, farmers, and farmworkers. He set out to better understand
"For starters, we found that most workers have to walk a short
distance from where they are working to get to the water provided,
and the physical `cost' of taking the walk, plus the associated
economic opportunity cost for those working on a piece-rate pay
basis, naturally counters the thirst impetus to take a drink," said
Rosenberg.
In their first field trial in May 1999, Rosenberg and his colleagues
focused on the amount and frequency of water intake by 25 vineyard
workers in two crews during an eight-day test period in Sonoma County.
Each of the 12 workers (including seven women) in one crew was provided
with a CamelBak ™ individualized water storage and delivery
system, a product designed for outdoor sports enthusiasts and recently
adopted as a standard issue by the U.S. Marine Corps. The other
13 workers had conventional access to drinking water held in an
"Igloo," a 10-gallon, insulated cooler-dispenser located at the
end of the row of grape vines.
"During pre-trial interviews, several workers had said that their
exertion during work, the tiredness and thirst that result, and
their water consumption depend a lot on pay basis. When on piece-rate,
they said, they tend to work harder, get more tired and thirsty,
and drink less," said Rosenberg. As expected, however, water intake
during the trial period was much greater for the group with CamelBaks
(CB) than those without, and the CB group reported considerably
smaller drops in energy from beginning to end of the work day. The
Igloo was 100 yards or more from where work was being performed
at times, and CB users outdrank the workers using the Igloo by more
than 2 to 1. "Although we shouldn't overgeneralize, our findings
certainly suggest that form of water availability and the delivery
system are important factors in actual intake, and increased intake
helps."
Rosenberg conducted a second field study in October 1999 to learn
primarily about patterns of water consumption in relation to temperature
and humidity over the workday. This trial involved 23 employees
of a vineyard management firm in Napa Valley, harvesting grapes
on a piece-rate basis in temperatures exceeding 90 degrees during
each of six days. "While the second study did not meet our high
hopes, it was an advance over the previous one and served as an
object lesson about the difficulty of conducting such research in
the real world."
The current requirement to make cool drinking water available
at all times is part of Cal/OSHA's "field sanitation standard" that
also covers toilet and hand-washing facilities. Stepped-up and targeted
enforcement of standards under Cal/OSHA's Agricultural Safety and
Health Inspection Program (ASHIP) in 1999 identified 50 employers,
nearly 10 percent of the 505 inspected, that were not in compliance.
A total of 56 violation notifications were issued for heat stress
hazards (19 classified as serious and 37 as general or regulatory)
with $36,000 in potential civil penalties.
A heat stress and hydration subgroup has been formed within the
DANR Ag Ergonomics Workgroup. Rosenberg will soon call this group
to virtual order on a new e-mail listserve and open a companion
Web site to support collaborative research and extension efforts
toward reducing harm from heat stress in agriculture. The site will
present educational articles, scientific and legal references, research
instruments and practical management documents (e.g., tailgate meeting
guidelines). Its launch will be announced through the Center and
other channels. For more information on this work, contact Rosenberg
by e-mail at howardr@are.berkeley.edu.
2000-03-05 NIOSH RECOMMENDS PROTECTION FOR WORKERS
EXPOSED TO CLASS B BIOSOLIDS
The National Institute for Occupational Safety and Health (NIOSH)
recommends practices to prevent the risk of disease among workers
who are exposed on the job to biosolids used to fertilize agricultural
lands or mine reclamation sites.
Biosolids are sewage sludge that has been treated to significantly
reduce or eliminate concentrations of bacteria, viruses, and other
microorganisms. At a level of treatment known as "Class B," some
microorganisms may still be present. Under environmental rules,
access for the general public to areas where Class B biosolids have
been applied is restricted for varying time periods up to one year,
allowing time for remaining microorganisms to die off naturally.
However, workers may be occupationally exposed in handling, applying,
or disturbing the material during this restricted period.
"Workers are the individuals most likely to be exposed to biosolids,
but practical steps can be taken to limit exposures and prevent
the possible risk of disease transmission," said NIOSH Director
Linda Rosenstock, M.D., M.P.H. "In the absence of definitive information
about the extent of risk to workers, our recommendations are based
on good public health practice," said Rosenstock.
NIOSH recommends that:
The recommendations are made in the NIOSH Hazard ID titled Workers
Exposed to Class B Biosolids During and After Field Application,
DHHS (NIOSH) Publication No. 2000-158. These Hazard ID documents
provide concise information and recommendations for preventing illnesses
or injuries in the workplace.
The Hazard ID, along with other NIOSH documents, can be ordered
through the NIOSH toll-free information number, 1-800-35-NIOSH (1-800-356-4674).
The document is also available on the NIOSH Web page at www.cdc.gov/niosh/hidlist.html.
NIOSH is the federal agency that conducts research and makes recommendations
for occupational health and safety. It is part of the U.S. Centers
for Disease Control and Prevention.
|
