PubLic Health Briefs
Council; and James Reid, MB, of the University of Otago Medical School for their assistance with the study and review of the manuscipt.
References 1. Craun GF: Surface water supplies and health. J Am Water Works Assoc 1988; 80:40-52. 2. Craun GF: Waterborne giardiasis in the United States 1965-1984. Lancet 1986; 2:513-514. 3. Jakubowski W: Purple burps and the filtration of drinking water supplies. (Editorial) Am J Public Health 1988; 78:139-143.
4. Kent GP, Greenspan JR, Herndon JL, et aL Epidemic giardiasis caused by a contaminated publicwater supply. Am J Public Health 1988; 78:139-143. 5. Jephcott AE, Begg NT, Baker IA: Outbreak of giardiasis associated with mains water in the United Kingdom. Lancet 1986; 2:730-732. 6. Chute CG, Smith RP, Baron JA: Risk factors for endemic giardiasis. Am J Public Health 1987; 77:585-587. 7. Birkhead G, Vogt RL: Epidemiological surveillance for endemic Giardia lamblia infection in Vermont. Am J Epidemiol 1989; 129:762-768.
8. Ongerth JE: Evaluation of treatment for removing Giarda cysts. J Am Water Works Assoc 1990; 82:85-96. 9. NZ Department of Statistics: 1986 New Zealand Census of population and dwellings, series B. Wellington: Department of Statistics, 1987. 10. Benenson AS (ed): Control of Communicable Disease in Man. Washington, DC: American Public Health Association, 1986. 11. Rothman K, Boice JD: Epidemiologic analysis with a programmable calculator. Boston: Epidemiology Resources, Inc, 1978.
The Microbiologic Quality of Drinking Water in North Carolina Migrant Labor Camps _X%s-----,
1
--
Stephen Ciesielstk, PhD, Thomas Handzel BS, and Mark Sobsey, PhD
Intodution Although migrant farm workers are known to have a high prevalence of enteric infections,1-7 many of which are water-borne, the potability of drinkingwater used by migrants has received little attention. This report presents the results of a two-year study of the microbiological quality of drinking water in North Carolina migrant labor camps.
Methds In 1988, a random sample of 21 migrant camps was selected from a pooled list of camps in eastern North Carolina.
Water
was also tested in six additional camps, which were part of a related study
of the incidence of enteric parasites in migrant farm workers, and 10 control sites
(nearby rural businesses and residences). In 1989, all 23 inhabited study camps from the previous year were retested, along with seven additional nonrandomly selected camps. In all camps in both years, water was tested by county health departments prior to occupancy, the results of which were obtained after field study was completed. Water samples were collected from taps (without aerators) into sterile 1 liter sampling bottles, kept chilled and analyzed within 24 hours. Microbiological testing of 100 ml sample volumes for total and fecal coliforms and E. coli was done
according to standard protocols using membrane filter methods.8 Sites with initial positive tests were retested when possible. Fisher's Exact Test (two-tailed) and Chi-square tests were employed in data analysis.
Results 1988 Results The bacteriological results for water samples from the 27 camps and 10 control sites are summarized in Table 1; 12 (44 percent) were positive for total coliforms with counts ranging from 1-186 colony forming units (CFU). Eight of these sites were retested and all were positive again. Seven samples (26 percent) were also positive for fecal coliforms. Two of 10 samples were positive for E. coli. All 10 control sites were negative for total and fecal coliforms. The presence of latrines (as opposed to flush toilets) was associated with total coliform occurrence in water (p = 0.024; Fisher's Exact Test). Address reprint requests to Stephen Ciesielski, PhD, Department of Parasitology and Laboratory Practice, School of Public Health, University of North Carolina, Chapel Hill, NC 27599. Mr. Handzel and Dr. Sobsey are with the Department of Environmental Sciences and Engineering at UNCSPH. This paper, submitted to the Journal April 26, 1990, was revised and accepted for publication January 23, 1991.
June 1991, Vol. 81, No. 6
Public Healfth Bnefs
The surprisingly high prevalence of total and fecal coliforms in migrant labor camp drinking water is a matter of serious concern. According to the US Environmental Protection Agency, "the presence of fecal coliforms in drinking water indicates that an urgent public health problem exists.",14 New standards proposed by the EPAwould require the state to be notified within 48 hours when any number of fecal coliforms are demonstrated."3 The health hazards associated with unsafe drinking water in migrant camps were demonstrated in 1973, when the largest outbreak of typhoid fever in the US since 1939 resulted from the contamination of well water in a Florida migrant camp, preceded by repeatedly high coliform counts in the
camp's water supply.14 North Carolina's migrant housing regulations require that water in migrant camps housing 13 or more workers be tested before occupancy for total coli-
forms.15'16 The failure of pre-occupancy inspections to ensure adequate water quality during habitation probably results
1989 Results Fifteen of 30 camps (50 percent) had water samples positive for total coliforms, 11 (37 percent) for fecal coliforms, and four forE. coli (Table 2). Fifty-six percent of resampled camps had the same result as the previous year. In 1989, latrines were not significantly associated with coliforms, but there was an increasing prevalence of coliforms in water samples as a function of time of occupancy. When the results of the four successive samplings of water are grouped as two early samplings and two late samplings, the total coliform prevalence in the early and late groups is significantly different by Chi-square analysis (p = 0.056). Rainfall during the week previous to the last two sampling periods totaled 3.68 inches while totaling 0.78 inches for the week prior to the first two
sampling periods.9 In 1988 only one and in 1989 none of the camps studied were positive for total coliforms on preoccupancy testing by local health departments.
Disusion In the United States over one-half of the reported outbreaks of waterborne dis-
June 1991, Vol. 81, No. 6
ease are due to fecally contaminated groundwater, most often resulting from overflow or seepage of on-site septic systems.10 Migrant camps are often overcrowded so that the amount of human fecal wastes may overload the design capacity of on-site sanitary disposal systems. These septic systems may also have exceeded their expected life span. Furthermore, migrants probably excrete greater numbers of pathogens into the septic waste system. Enteric infections, especially parasites, are major health problems among migrants.1`7 Diarrhea is reported to be 20 times more frequent among migrants than the urban poor.4 Most intestinal parasites identified in the migrant population can be transmitted by fecally contaminated water' 3'5'11 and enteric bacteria and viruses have a much greater capacity for waterborne transmission.7 The concurrent study of the incidence of intestinal parasites in which some study camps were included, found a significant association (p = .024) between incidence and total coliforms.* In Florida an echovirus (type 22/23 complex) was isolated from water samples in a migrant camp during an outbreak of gastrointestinal illness.12
from the fact that if coliforms have entered the water system when the camp is occupied in late summer, results are negative the following June (after a nine-month vacancy) due to bacterial die-off and dilution and dispersion in ground water. This variation with usage is supported by the increase in coliform prevalence observed in 1989 with each round of sampling, which suggests that overload of on-site waste water treatment facilities may be a factor. Increasing rainfall in the early autumn may also play a role. On the basis of these findings, it seems logical to suggest that current regulations be revised to include water quality testing both before and during the period of habitation, not only in North Carolina, but in all states in which migrants are served by ground water sources. Further study is needed to determine the factors responsible for the presence of coliforms in drinldng water so that effective intervention can be initiated. [l
Acknowledgments Funding for this studywas provided by the Rural CommunityAssistance Program, 602South King Street, Suite 402, Leesburg, VA 22075; speial thanks are expressed to Kathleen Stanley, Acting Diector. Additional fundingwas provided by the Tri-County Community Health Center, Newton *Ciesielski SD, Seed JR, Ortiz JC, Metts J: The epidemiology of intestinal parasites among North Carolina migrant farmworkers: Results of a two-year long study. Unpublished data.
American Journal of Public Health 763
Public Health Briefs
Grove, NC; specal thanks are expressed to the clinic's Director, Michael Baker. 1. Ciesielski SD, Seed JR: Preliminary report: Intestinal parasites in adult migrant farmworkers in North Carolina. Migrant Health Newsline, Migrant Clinicians Network, Austin, Texas, 1988; 5:3-5. 2. Arbab DM, WeidnerB: Infectious diseases and field water supply and sanitation among migrant farmworkers. Am J Public Health 1986; 76:694-695. 3. Ungar BL, Iscoe E, Cutler J, Bartlett JG: Intestinal parasites in a migrant farmworker population. Arch Intern Med 1986; 146:513-515. 4. Wilk VA: The Occupational Health of Migrant and Seasonal Farmworkers in the United States. Washington, DC: Farmworker Justice Fund, 1986. 5. Ortiz J: The prevalence of intestinal parasites in Puerto Rican farmworkers in west-
6.
7. 8.
9.
em Massachusetts. Am J Public Health 1980; 70:1103-1105. Centaur Associates, Inc: Final Report: Industry Profile Phase I. Study Field Sanitation. Washington, DC: Centaur Associates, September 1983. Federal Register 52(84):16050-16096. American Public Health Association: Standard Methods For the Examination of Water and Wastewater. Washington, DC: APHA, 1989. National Climatic Data Center, Asheville, NC, September and October, 1988, and
September and October, 1989. 10. Environmental Protection Agency: Septic Tank Siting to Minimize the Contamination of Ground Water by Microorganisms. Washington, DC: EPA, 1987. 11. Mcjunkin FE: Water and Human Health. Washington, DC: National Demonstration Water Project, 1982.
12. Wellings FM, Mountain CW, Lewis AL: Virus in groundwater. In: Proc. 2nd National Conference on Individual On-Site Wastewater Systems, Ann Arbor Science, Ann Arbor, MI 1977; 61. 13. Environmental Protection Agency: Proposed Rules. Federal Register, June 29, 1989, 54FR27544. 14. Hoffman TA: Waterborne typhoid fever in Dade County, Florida: Clinical and therapeutic evaluation of 105 bacteremic patients. Am J Med 1975; 59:481487. 15. North Carolina Drinking WaterAct, 130A311. 16. North Carolina State and Federal Laws Affecting Migrant and Seasonal Farmworkers. Governors Special Grant, North Carolina Department of Natural Resources and Community Development, Raleigh, NC.
Salmonella Egg Survey in Hawaii: Evidence for Routine Bacterial Surveillance Gli.;.lls-aD=c[s-s~~~~~~~~~~~~~~~~~~~~~~~~~~~....iii.... ~
~
~ .. ~~.........
D_en. hinm
Myra R Ching-Lee, MPH, Alan R Katz, MD, MPH, David M. Sasaki, DVM, MPH, and Henri P. Minette, DrPH
udm%&
Intodudion "INX~~~~~~ta IN, -Rillf
._.. 4tI S>:lBw;:^;x:sexUIEUP
4444444444
:
Large outbreaks of human salmonellosis in the United States, related to egg products and cracked shell eggs, led to the passage of the Egg Products Act in 1970. This law required visual inspection of eggs for cracks as well as mandating pasteurization for all bulk egg products. 12 Although this legislation led to an initial decrease in egg-related Salmonella outbreaks, they have again begun to rise.-5 Contamination of eggs with SabnoneUla can occur in several ways: egg shells may be contaminated by feces6; cleaning procedures may be improper7; the interior of the egg may be contaminated by the shell being cracked. Contamination may also be intemal, prior to shell formation through transovarian transmission.5,8 In 1989, an Oahu high school student, as part of a science project, cultured two dozen eggs from a supermarket in Honolulu for SalmoneUla. Nine of 24 eggs (37 percent) were culture positive. The high recoveiy rate prompted the Hawaii State Department of Health to conduct a more defini-
tive prevalence survey for Salmonella among eggs for sale in Oahu supermarkets.
Mehod Eggs representing 12 available brands were collected once each week for an eight-week period from June 26 through August 19, 1989. The sampling unit was defined as a carton of 12 large grade A eggs. The carton closest to the aisle was chosen without opening it. Following collection, the eggs were immediately transported to the Hawaii State DeFrom the University of Hawaii School of Public Health, and the Hawaii State Department of Health. Address reprint requests to Myra R. Ching-Lee, MPH, Epidemiological Specialist, Communicable Disease Division, Epidemiology Branch, 1250 Punchbowl St., Rm. 107, Honolulu, HI 96813. Dr. Katz is Assistant Professor of Public Health Sciences at the University; Dr. Sasald is Veterinary Medical Officer, Communicable Disease Division, Hawaii Department of Health; Dr. Minette is Epidemiology Consultant to the Hawaii State Departnent of Health. This paper, submitted to the Journal February 27, 1990, was revised and accepted for publication December 20, 1990.
June 1991, Vol. 81, No. 6
Council; and James Reid, MB, of the University of Otago Medical School for their assistance with the study and review of the manuscipt.
References 1. Craun GF: Surface water supplies and health. J Am Water Works Assoc 1988; 80:40-52. 2. Craun GF: Waterborne giardiasis in the United States 1965-1984. Lancet 1986; 2:513-514. 3. Jakubowski W: Purple burps and the filtration of drinking water supplies. (Editorial) Am J Public Health 1988; 78:139-143.
4. Kent GP, Greenspan JR, Herndon JL, et aL Epidemic giardiasis caused by a contaminated publicwater supply. Am J Public Health 1988; 78:139-143. 5. Jephcott AE, Begg NT, Baker IA: Outbreak of giardiasis associated with mains water in the United Kingdom. Lancet 1986; 2:730-732. 6. Chute CG, Smith RP, Baron JA: Risk factors for endemic giardiasis. Am J Public Health 1987; 77:585-587. 7. Birkhead G, Vogt RL: Epidemiological surveillance for endemic Giardia lamblia infection in Vermont. Am J Epidemiol 1989; 129:762-768.
8. Ongerth JE: Evaluation of treatment for removing Giarda cysts. J Am Water Works Assoc 1990; 82:85-96. 9. NZ Department of Statistics: 1986 New Zealand Census of population and dwellings, series B. Wellington: Department of Statistics, 1987. 10. Benenson AS (ed): Control of Communicable Disease in Man. Washington, DC: American Public Health Association, 1986. 11. Rothman K, Boice JD: Epidemiologic analysis with a programmable calculator. Boston: Epidemiology Resources, Inc, 1978.
The Microbiologic Quality of Drinking Water in North Carolina Migrant Labor Camps _X%s-----,
1
--
Stephen Ciesielstk, PhD, Thomas Handzel BS, and Mark Sobsey, PhD
Intodution Although migrant farm workers are known to have a high prevalence of enteric infections,1-7 many of which are water-borne, the potability of drinkingwater used by migrants has received little attention. This report presents the results of a two-year study of the microbiological quality of drinking water in North Carolina migrant labor camps.
Methds In 1988, a random sample of 21 migrant camps was selected from a pooled list of camps in eastern North Carolina.
Water
was also tested in six additional camps, which were part of a related study
of the incidence of enteric parasites in migrant farm workers, and 10 control sites
(nearby rural businesses and residences). In 1989, all 23 inhabited study camps from the previous year were retested, along with seven additional nonrandomly selected camps. In all camps in both years, water was tested by county health departments prior to occupancy, the results of which were obtained after field study was completed. Water samples were collected from taps (without aerators) into sterile 1 liter sampling bottles, kept chilled and analyzed within 24 hours. Microbiological testing of 100 ml sample volumes for total and fecal coliforms and E. coli was done
according to standard protocols using membrane filter methods.8 Sites with initial positive tests were retested when possible. Fisher's Exact Test (two-tailed) and Chi-square tests were employed in data analysis.
Results 1988 Results The bacteriological results for water samples from the 27 camps and 10 control sites are summarized in Table 1; 12 (44 percent) were positive for total coliforms with counts ranging from 1-186 colony forming units (CFU). Eight of these sites were retested and all were positive again. Seven samples (26 percent) were also positive for fecal coliforms. Two of 10 samples were positive for E. coli. All 10 control sites were negative for total and fecal coliforms. The presence of latrines (as opposed to flush toilets) was associated with total coliform occurrence in water (p = 0.024; Fisher's Exact Test). Address reprint requests to Stephen Ciesielski, PhD, Department of Parasitology and Laboratory Practice, School of Public Health, University of North Carolina, Chapel Hill, NC 27599. Mr. Handzel and Dr. Sobsey are with the Department of Environmental Sciences and Engineering at UNCSPH. This paper, submitted to the Journal April 26, 1990, was revised and accepted for publication January 23, 1991.
June 1991, Vol. 81, No. 6
Public Healfth Bnefs
The surprisingly high prevalence of total and fecal coliforms in migrant labor camp drinking water is a matter of serious concern. According to the US Environmental Protection Agency, "the presence of fecal coliforms in drinking water indicates that an urgent public health problem exists.",14 New standards proposed by the EPAwould require the state to be notified within 48 hours when any number of fecal coliforms are demonstrated."3 The health hazards associated with unsafe drinking water in migrant camps were demonstrated in 1973, when the largest outbreak of typhoid fever in the US since 1939 resulted from the contamination of well water in a Florida migrant camp, preceded by repeatedly high coliform counts in the
camp's water supply.14 North Carolina's migrant housing regulations require that water in migrant camps housing 13 or more workers be tested before occupancy for total coli-
forms.15'16 The failure of pre-occupancy inspections to ensure adequate water quality during habitation probably results
1989 Results Fifteen of 30 camps (50 percent) had water samples positive for total coliforms, 11 (37 percent) for fecal coliforms, and four forE. coli (Table 2). Fifty-six percent of resampled camps had the same result as the previous year. In 1989, latrines were not significantly associated with coliforms, but there was an increasing prevalence of coliforms in water samples as a function of time of occupancy. When the results of the four successive samplings of water are grouped as two early samplings and two late samplings, the total coliform prevalence in the early and late groups is significantly different by Chi-square analysis (p = 0.056). Rainfall during the week previous to the last two sampling periods totaled 3.68 inches while totaling 0.78 inches for the week prior to the first two
sampling periods.9 In 1988 only one and in 1989 none of the camps studied were positive for total coliforms on preoccupancy testing by local health departments.
Disusion In the United States over one-half of the reported outbreaks of waterborne dis-
June 1991, Vol. 81, No. 6
ease are due to fecally contaminated groundwater, most often resulting from overflow or seepage of on-site septic systems.10 Migrant camps are often overcrowded so that the amount of human fecal wastes may overload the design capacity of on-site sanitary disposal systems. These septic systems may also have exceeded their expected life span. Furthermore, migrants probably excrete greater numbers of pathogens into the septic waste system. Enteric infections, especially parasites, are major health problems among migrants.1`7 Diarrhea is reported to be 20 times more frequent among migrants than the urban poor.4 Most intestinal parasites identified in the migrant population can be transmitted by fecally contaminated water' 3'5'11 and enteric bacteria and viruses have a much greater capacity for waterborne transmission.7 The concurrent study of the incidence of intestinal parasites in which some study camps were included, found a significant association (p = .024) between incidence and total coliforms.* In Florida an echovirus (type 22/23 complex) was isolated from water samples in a migrant camp during an outbreak of gastrointestinal illness.12
from the fact that if coliforms have entered the water system when the camp is occupied in late summer, results are negative the following June (after a nine-month vacancy) due to bacterial die-off and dilution and dispersion in ground water. This variation with usage is supported by the increase in coliform prevalence observed in 1989 with each round of sampling, which suggests that overload of on-site waste water treatment facilities may be a factor. Increasing rainfall in the early autumn may also play a role. On the basis of these findings, it seems logical to suggest that current regulations be revised to include water quality testing both before and during the period of habitation, not only in North Carolina, but in all states in which migrants are served by ground water sources. Further study is needed to determine the factors responsible for the presence of coliforms in drinldng water so that effective intervention can be initiated. [l
Acknowledgments Funding for this studywas provided by the Rural CommunityAssistance Program, 602South King Street, Suite 402, Leesburg, VA 22075; speial thanks are expressed to Kathleen Stanley, Acting Diector. Additional fundingwas provided by the Tri-County Community Health Center, Newton *Ciesielski SD, Seed JR, Ortiz JC, Metts J: The epidemiology of intestinal parasites among North Carolina migrant farmworkers: Results of a two-year long study. Unpublished data.
American Journal of Public Health 763
Public Health Briefs
Grove, NC; specal thanks are expressed to the clinic's Director, Michael Baker. 1. Ciesielski SD, Seed JR: Preliminary report: Intestinal parasites in adult migrant farmworkers in North Carolina. Migrant Health Newsline, Migrant Clinicians Network, Austin, Texas, 1988; 5:3-5. 2. Arbab DM, WeidnerB: Infectious diseases and field water supply and sanitation among migrant farmworkers. Am J Public Health 1986; 76:694-695. 3. Ungar BL, Iscoe E, Cutler J, Bartlett JG: Intestinal parasites in a migrant farmworker population. Arch Intern Med 1986; 146:513-515. 4. Wilk VA: The Occupational Health of Migrant and Seasonal Farmworkers in the United States. Washington, DC: Farmworker Justice Fund, 1986. 5. Ortiz J: The prevalence of intestinal parasites in Puerto Rican farmworkers in west-
6.
7. 8.
9.
em Massachusetts. Am J Public Health 1980; 70:1103-1105. Centaur Associates, Inc: Final Report: Industry Profile Phase I. Study Field Sanitation. Washington, DC: Centaur Associates, September 1983. Federal Register 52(84):16050-16096. American Public Health Association: Standard Methods For the Examination of Water and Wastewater. Washington, DC: APHA, 1989. National Climatic Data Center, Asheville, NC, September and October, 1988, and
September and October, 1989. 10. Environmental Protection Agency: Septic Tank Siting to Minimize the Contamination of Ground Water by Microorganisms. Washington, DC: EPA, 1987. 11. Mcjunkin FE: Water and Human Health. Washington, DC: National Demonstration Water Project, 1982.
12. Wellings FM, Mountain CW, Lewis AL: Virus in groundwater. In: Proc. 2nd National Conference on Individual On-Site Wastewater Systems, Ann Arbor Science, Ann Arbor, MI 1977; 61. 13. Environmental Protection Agency: Proposed Rules. Federal Register, June 29, 1989, 54FR27544. 14. Hoffman TA: Waterborne typhoid fever in Dade County, Florida: Clinical and therapeutic evaluation of 105 bacteremic patients. Am J Med 1975; 59:481487. 15. North Carolina Drinking WaterAct, 130A311. 16. North Carolina State and Federal Laws Affecting Migrant and Seasonal Farmworkers. Governors Special Grant, North Carolina Department of Natural Resources and Community Development, Raleigh, NC.
Salmonella Egg Survey in Hawaii: Evidence for Routine Bacterial Surveillance Gli.;.lls-aD=c[s-s~~~~~~~~~~~~~~~~~~~~~~~~~~~....iii.... ~
~
~ .. ~~.........
D_en. hinm
Myra R Ching-Lee, MPH, Alan R Katz, MD, MPH, David M. Sasaki, DVM, MPH, and Henri P. Minette, DrPH
udm%&
Intodudion "INX~~~~~~ta IN, -Rillf
._.. 4tI S>:lBw;:^;x:sexUIEUP
4444444444
:
Large outbreaks of human salmonellosis in the United States, related to egg products and cracked shell eggs, led to the passage of the Egg Products Act in 1970. This law required visual inspection of eggs for cracks as well as mandating pasteurization for all bulk egg products. 12 Although this legislation led to an initial decrease in egg-related Salmonella outbreaks, they have again begun to rise.-5 Contamination of eggs with SabnoneUla can occur in several ways: egg shells may be contaminated by feces6; cleaning procedures may be improper7; the interior of the egg may be contaminated by the shell being cracked. Contamination may also be intemal, prior to shell formation through transovarian transmission.5,8 In 1989, an Oahu high school student, as part of a science project, cultured two dozen eggs from a supermarket in Honolulu for SalmoneUla. Nine of 24 eggs (37 percent) were culture positive. The high recoveiy rate prompted the Hawaii State Department of Health to conduct a more defini-
tive prevalence survey for Salmonella among eggs for sale in Oahu supermarkets.
Mehod Eggs representing 12 available brands were collected once each week for an eight-week period from June 26 through August 19, 1989. The sampling unit was defined as a carton of 12 large grade A eggs. The carton closest to the aisle was chosen without opening it. Following collection, the eggs were immediately transported to the Hawaii State DeFrom the University of Hawaii School of Public Health, and the Hawaii State Department of Health. Address reprint requests to Myra R. Ching-Lee, MPH, Epidemiological Specialist, Communicable Disease Division, Epidemiology Branch, 1250 Punchbowl St., Rm. 107, Honolulu, HI 96813. Dr. Katz is Assistant Professor of Public Health Sciences at the University; Dr. Sasald is Veterinary Medical Officer, Communicable Disease Division, Hawaii Department of Health; Dr. Minette is Epidemiology Consultant to the Hawaii State Departnent of Health. This paper, submitted to the Journal February 27, 1990, was revised and accepted for publication December 20, 1990.
June 1991, Vol. 81, No. 6
