THE JOURNAL OF INFECTIOUS DISEASES. VOL. 136, NO.2. AUGUST 1977 © 1977 by the University of Chicago. All rights reserved.
From the Center for Disease Control Brucellosis in the United States, 1965-1974 In the decade 1965-1974,2,302 cases of brucellosis in humans were reported in the United States. The annual number of cases progressively declined from 262 in 1965 to 175 in 1973; the downward trend was reversed in 1974, when 247 cases were reported (table I). This resurgence appears to be directly related to the increasing incidence of bovine brucellosis. During the 10-year period, the Center for Disease Control (CDC; Atlanta, Ga.) received case surveillance reports on 2,047 (89%) of the human cases, including 1,891 newly acquired and 156 recrudescent infections. This report summarizes information on these cases. Cases of brucellosis were reported by all states but Delaware and Nevada (figure I). Six states (Iowa, Virginia, California, Texas, Illinois, and Georgia) each reported more than 100 cases and together accounted for 1,341 (58%) of the 2,302 cases. l\;fonth of onset of brucellosis was recorded in 1,969 cases. About one-third of the cases (around 225 a month) had onset in April, lVIay, and June. The lowest incidence occurred in the fall, with a steady decline in cases from September (139) Please address requests for reprints to Dr. Marshall D. Fox, Bacterial Diseases Division, Bureau of Epidemiology, Center for Disease Control, Atlanta, Georgia 30333.
Table 1.
Year
1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 Total
Reported cases of brucellosis in humans, by year, United States, 1965-1974.
Total no. of cases reported
262 262 258 251 234 235 190 188 175 247
Case rate per 100,000 population *
No. (%) of case reports received of Newly acquired infections
0.14 0.13 0.13 0.13 0.12 0.12 0.09 0.09 0.08 0.12
205 (92) 191 (89) 184 (89) 200 (93) 195 (92) 180 (89) 160 (91) 176 (96) 168 (97) 232 (97)
2,302
1,891 (92)
*Based on yearly July 1 population estimates published by the Bureau of Census.
312
Recrudescent infections
19 (8) 23 (11) 23 (11) 16 (7) 18 (8) 22 (11) 16 (9) 7 (4) 6 (3) 6 (3) 156 (8)
Total
224 214 207 216 213 202 176 183 174 238 2,047
Downloaded from http://jid.oxfordjournals.org/ at Yale University on July 4, 2015
through December (61). Between 150 and 200 cases had onset in each of the other months. Distribution of cases by age and sex showed that brucellosis primarily affected adult males. "Men between the ages of 20 and 60 years accounted for 1,432 (73%) of the 1,950 cases in which age and sex were reported. The sex distribution of cases was more balanced in children and elderly persons than in working-age adults. Clinical features of brucellosis. The clinical features of brucellosis were available for 1,288 cases reported after 1967. Seven symptoms were reported by more than half of the patients: fever (89%), chills (69%), weakness and malaise (64%), body ache and sweating (61 %), and headache (51%). In addition, weight loss was reported by 4 I% and anorexia by 39%. Fever was more commonly intermittent (83% of cases with course of fever specified) than constant (17%). Five (0.24%) of the 2,047 patients died, but brucellosis was considered to be the primary cause of death in only two of these. In addi tion, two pregnant patients aborted; Brucella suis was isolated from the blood of one woman and from uterine fluid of the other. For culture-confirmed cases, duration of illness was similar for infections due to B. suis, Brucella abortus, and Brucella melitensis, with a median of four weeks. Antimicrobial therapy was specified for 752 patients in 1970-1974. Tetracycline or a tetracycline
313
CDC News
---'
Figure 1. Cases of brucellosis in humans, by state, 1965-1974
analogue was administered to 678 (90%) of the patients; of these, 321 (47%) also received streptomycin. Of 524 cases in which the dosage of tetracycline was specified, only 357 (68%) of the patients received the minimal recommended course of 2 g orally per day for 21 days. SOUTce of infection. A definite or probable
source of infection was determined in 1,802 (88%) of the 2,047 reported cases. Domestic swine, the most commonly reported source in each of the 10 years, were considered to be the source of 795 (39%) of the 2,047 cases. Another seven cases occurred in hunters who killed and butchered feral swine in the southeastern and south central
Table 2. Most probable source of brucellosis by occupational group of patients, United States, 1965-1974. Occupational group Source Domestic animals Swine Cattle Swine or cattle Sheep or goats Unspecified farm animals Dogs Wild animals Caribou or moose Feral swine Deer Unpasteurized dairy products Domestic Foreign Accidents Strain 19 vaccine Laboratory Unknown Total (%)
Meat-processing mdustry
Livestock industry
Other and unknown
Total
60 5 4 0
39 52 45 6 2 6
795 352 291 18 63 6
0 0 0
0 0 0
12 7 2
12 7 2
0 0
7 2
57 125
64 127
0 0 0
31 0 12
0 34 233
31 34 245
702 121 186 7 57 0
1,073 (52.4)
54 179
354 (17.3)
620 (30.3)
2,047
Downloaded from http://jid.oxfordjournals.org/ at Yale University on July 4, 2015
1° ;.~ IL-·
314
Fox and Kaufmanll
period 1970-1974 showed that only a few packing plants accounted for most swine-associated cases. Of 364 cases acquired at swine abattoirs in the period, the packing company was identified in 349 (96%). Of these, 256 cases (73%) occurred in employees of six abattoirs located in California, Georgia, Illinois, Iowa, and Virginia (two plants). Hogs slaughtered at the six plants originated primarily from farms in the lVlidwest (three plants) and Southeast (three plants) and represented
From the Center for Disease Control Brucellosis in the United States, 1965-1974 In the decade 1965-1974,2,302 cases of brucellosis in humans were reported in the United States. The annual number of cases progressively declined from 262 in 1965 to 175 in 1973; the downward trend was reversed in 1974, when 247 cases were reported (table I). This resurgence appears to be directly related to the increasing incidence of bovine brucellosis. During the 10-year period, the Center for Disease Control (CDC; Atlanta, Ga.) received case surveillance reports on 2,047 (89%) of the human cases, including 1,891 newly acquired and 156 recrudescent infections. This report summarizes information on these cases. Cases of brucellosis were reported by all states but Delaware and Nevada (figure I). Six states (Iowa, Virginia, California, Texas, Illinois, and Georgia) each reported more than 100 cases and together accounted for 1,341 (58%) of the 2,302 cases. l\;fonth of onset of brucellosis was recorded in 1,969 cases. About one-third of the cases (around 225 a month) had onset in April, lVIay, and June. The lowest incidence occurred in the fall, with a steady decline in cases from September (139) Please address requests for reprints to Dr. Marshall D. Fox, Bacterial Diseases Division, Bureau of Epidemiology, Center for Disease Control, Atlanta, Georgia 30333.
Table 1.
Year
1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 Total
Reported cases of brucellosis in humans, by year, United States, 1965-1974.
Total no. of cases reported
262 262 258 251 234 235 190 188 175 247
Case rate per 100,000 population *
No. (%) of case reports received of Newly acquired infections
0.14 0.13 0.13 0.13 0.12 0.12 0.09 0.09 0.08 0.12
205 (92) 191 (89) 184 (89) 200 (93) 195 (92) 180 (89) 160 (91) 176 (96) 168 (97) 232 (97)
2,302
1,891 (92)
*Based on yearly July 1 population estimates published by the Bureau of Census.
312
Recrudescent infections
19 (8) 23 (11) 23 (11) 16 (7) 18 (8) 22 (11) 16 (9) 7 (4) 6 (3) 6 (3) 156 (8)
Total
224 214 207 216 213 202 176 183 174 238 2,047
Downloaded from http://jid.oxfordjournals.org/ at Yale University on July 4, 2015
through December (61). Between 150 and 200 cases had onset in each of the other months. Distribution of cases by age and sex showed that brucellosis primarily affected adult males. "Men between the ages of 20 and 60 years accounted for 1,432 (73%) of the 1,950 cases in which age and sex were reported. The sex distribution of cases was more balanced in children and elderly persons than in working-age adults. Clinical features of brucellosis. The clinical features of brucellosis were available for 1,288 cases reported after 1967. Seven symptoms were reported by more than half of the patients: fever (89%), chills (69%), weakness and malaise (64%), body ache and sweating (61 %), and headache (51%). In addition, weight loss was reported by 4 I% and anorexia by 39%. Fever was more commonly intermittent (83% of cases with course of fever specified) than constant (17%). Five (0.24%) of the 2,047 patients died, but brucellosis was considered to be the primary cause of death in only two of these. In addi tion, two pregnant patients aborted; Brucella suis was isolated from the blood of one woman and from uterine fluid of the other. For culture-confirmed cases, duration of illness was similar for infections due to B. suis, Brucella abortus, and Brucella melitensis, with a median of four weeks. Antimicrobial therapy was specified for 752 patients in 1970-1974. Tetracycline or a tetracycline
313
CDC News
---'
Figure 1. Cases of brucellosis in humans, by state, 1965-1974
analogue was administered to 678 (90%) of the patients; of these, 321 (47%) also received streptomycin. Of 524 cases in which the dosage of tetracycline was specified, only 357 (68%) of the patients received the minimal recommended course of 2 g orally per day for 21 days. SOUTce of infection. A definite or probable
source of infection was determined in 1,802 (88%) of the 2,047 reported cases. Domestic swine, the most commonly reported source in each of the 10 years, were considered to be the source of 795 (39%) of the 2,047 cases. Another seven cases occurred in hunters who killed and butchered feral swine in the southeastern and south central
Table 2. Most probable source of brucellosis by occupational group of patients, United States, 1965-1974. Occupational group Source Domestic animals Swine Cattle Swine or cattle Sheep or goats Unspecified farm animals Dogs Wild animals Caribou or moose Feral swine Deer Unpasteurized dairy products Domestic Foreign Accidents Strain 19 vaccine Laboratory Unknown Total (%)
Meat-processing mdustry
Livestock industry
Other and unknown
Total
60 5 4 0
39 52 45 6 2 6
795 352 291 18 63 6
0 0 0
0 0 0
12 7 2
12 7 2
0 0
7 2
57 125
64 127
0 0 0
31 0 12
0 34 233
31 34 245
702 121 186 7 57 0
1,073 (52.4)
54 179
354 (17.3)
620 (30.3)
2,047
Downloaded from http://jid.oxfordjournals.org/ at Yale University on July 4, 2015
1° ;.~ IL-·
314
Fox and Kaufmanll
period 1970-1974 showed that only a few packing plants accounted for most swine-associated cases. Of 364 cases acquired at swine abattoirs in the period, the packing company was identified in 349 (96%). Of these, 256 cases (73%) occurred in employees of six abattoirs located in California, Georgia, Illinois, Iowa, and Virginia (two plants). Hogs slaughtered at the six plants originated primarily from farms in the lVlidwest (three plants) and Southeast (three plants) and represented
