Document pe2e25X2x0G6V77j3nQe3jZ56

^VofyAIorinateti Biphenyl: Xateracfioa wlflt4 * l>ack Btpafids VkaT ' Abstract Ten-day-old mallard ducklings fed a polychlorinated biphenyl at concentrations of 25, SO, and 100 parts per mBtion for 10 days suffered no apparent clinical Intoxication. Five days later these birds were challenged with duck hepatitis virus, and they suffered significantly higher mortality than birds which were not 'exposed to the polychlorinated biphenyl. ............. ' Polychlorinated biphenyl* (PCB) along with DDE [l,l-dichIoro-2,2-bB(p-chlorophenyi)ethane] are reported . to be the most abundant of the chlo rinated hydrocarbon polhXants in the - global ecosystem (1). Despite the fact that PCB's have been in wide use since 1930 (2), they remained eco logically inconspicuous until 1966 when -a 'Swedish chemist reported their pres .. ence in the tissues of pike and other " wildlife (J), Since then, their presence has been jeported in additional wild-. . life of Europe and North America (/, 4). These compounds are interesting because they are an important source of interference in the chemical detcction of DDT and its metabolites (5) and bccausc' thcy are a potential hazard in the environment; on a weight basis PCB preparations have been shown to have an estradiol-degrading potential about five times that of p,/i'-DDE or tcchni. cal grade DDT [ 1,1,1 -trichloro-2,2-bis(p-chlorophcnyl)cthanc] (/). As part of an investigation of possiMe interactions between organochlorinc pollutants and infectious diseases, this . study was initiated to determine whether any interaction, antagonistic or synergistic, occurs with PCB and duck -hepatitis virus (DHV) in mallards . (Anas platyrhynchos). ' - Four separate diets, three with PCB . and one .without, of a standard duck starter ration were fed to groups of 10-day-old mallard ducklings. The three PCB diets contained Arodor 1254 (in a corn oil premix) concentrations cal culated to be 25, SO, and 100 parts per million (ppm). These diets were fed to five groups of 25 ducklings each, three principal and two control groups i (Table 1). . All birds were leg-banded with colorcoded, numbered bands, weighed, and fed their respective diets for 10 days. - On day 11 each bird was weighed again, and every fifth bird from each treatment group was killed. Tissues - were collected for residue analysis, his1 lolojjy, and liver weights. During the 10-day feeding trial, no birds died or isolation units where they were main became clinically ill, although duck lings in the group given 100 ppm PCB were noticeably hyperexcitable after day 3 as were those in the 50-ppm tained on PCB-free feed and water for 3 days before being- challenged with DHV. No birds died or became clinically ill during the interim period group 4 days after treatment between PCB feeding and virus chal Body weights of birds receiving PCB lenge although two birds were lost from in their diet were significantly heavier the 100-ppm group due to accidents. at the end of the 10-day feeding trial On day 15 of the experiment all but. than those fed the diet without PCB the untreated controls (birds not re- (Table 1). The heaviest body weights ceiving either PCB or DHV) were in- ' occurred in birds fed the highest con oculated intraperitoneally with 1.5 L centrations of PCB, and the'trend ap LDr^* (50 percent effective lethal dose peared to be linear. Differences in body for docks) of DHV per bird. The weights among treatment means were first birds died about 47 - hours after highly significant (F = 20.30, d.f. =_ inoculation. Mortality was recorded 4, 119) when tested by analysis of hourly for the remainder of the 80- covariance. No statistical comparisons hour experimental period with one ex- between individual treatment means ccplion; there were no observations be- . were made. A similar analysis of liver tween hours 63 through 69. The onset weights (determined as a percentage of of mortality m all groups given PCB . final body weight) disclosed highly sig .plus DHV began at least 8 'to 16 hours nificant differences among treatment before that in the control group treated means (F = 5.82, df. = 4, 18). These with the virus only (Fig. I). In addi differences appeared to be within tion, mortality levels occurring among groups treated with PCB rather than PCB-plus-virus treatment groups at the between treated and untreated groups end of the experiment were significantly (Table 1). The small sample sizes (N = ' higher at the .01 level of probability. 5) necessitates caution in interpretation than for ducklings receiving the virus of liver weight data. No interpretation only (chi square = 7.49, d.f. = 1). of differences among body and liver There was no significant difference in' - weights are offered at this time. mortality among ducklings receiving the different concentrations of PCB plus Table I. Final mean body and liver weifhtt at eullard ducklings after bcins fed PCB ' (Aroclor 1254, Monsanto, St. Louis) for 10 days. Numbers in parentheses are the number of bints used. The liver and body weights were adjusted by covariance for a common starting mean; the liver weight was determined as percentage of body weight. The final coo- trot did not receive either PCB or DIIV. vinis (chi square = 3.79, d.f. -- 2). No birds in the untreated group died (Table 2). All birds that died during the experi ment had gross pathognomonic liver lesions, indicating typical duck hepa titis infection (6). No other gross Treatment PCB (PPm) PCB + DHV PCB + DHV PCB + DHV DHV control Control too 50 25 0 '0 llody wci&hl (S) 381.6 (25) 36S.8 (25) 3524(25) 3154 (25) 3094 (25) IJvcr weight (s) 0.046 (5) 437 (5) 429(5) 436 (4) 434(5) lesions, with the exception of varying amounts of edema within the peri cardium and_ thoracic cavity of some birds, were observed. There did not ap- . pear to be any relation between treat ment and the presence or absence of edema. Histological and residue analy- sis have not been completed at this : time. Twelve days after the experiment be The suggestions that PCB may render gan, birds were placed in crates and - a host more susceptible to certain types transported approximately 5 miles to of infectious agents is the significant lover] 18 December 1970 DSW 282631 SCIENCE, Vol. 170 STLCOPCB4063960 griding m tins tioSf. None of tfco con- ccntratioiis of PCB fed resulted tn.de- ' leetable chemical intoxication w with the physical stresses of weighing. ] handling, confinemeat, and crowding during transportation, transportation it _TkNe 2. Mortality among nilUrff 3uctJlnes earned by DHV during an SO-hour eOserimcnul period. Ho observations were made betwceoJH lo 47 tad <2 to TO hours. The final control did not receive cither PCB or DHV.' ' ......... - _ V . ; -t,. .Treatmeat__^ " PCB (ppm) ' Mortality No. of deaths/ total sample Percentage Onset (hours) Cessation (hours) self, or relocation in a different environ ment. However, when the stress of an ' infectious agent was added, these sublelhal concentrations appeared to in PCB + DHV PCB + DHV. PCB + DHV DHV control Control 100 50 25 t/IC 13/20 7/20 3/21 /20 . | 44.4 C5j0 35J) i 14J ' 0J> 31-47 55. 31-47 C2-70 75 74 75 . 73 fluence the resulting mortality rates, causing two- to fourfold increases (14 percent among virus controls versos 35 _ ....... : m . .. . . .------- . . ** .- to 65 percent among groups receiving PCB plus DHV) and reduced incuba CO- tion time (Fig. 1 and Table 2). Similar increases in mortality were obtained with other organochiorine compounds in our laboratory (7). In 40- those studies 30-day-old mallard duck lings which had been fed sublethal con n %oz centrations of p,p'~DDT or dicldrln exhibited three- to ninefold increales 20 - in mortality over that of DHV controls (6 percent among virus controls versus 19 to 59 percent among groups receiv ing dieldrin plus DHV, and 19 to 40 percent among groups receiving p,pfDDT plus DHV). It is unlikely that _ in aU these instances mortality in the DHV control groups would be less than half that in any interaction group on the basis of chance alone. This study illustrates one of the po CO : 70 Time (hours) Fig. 1. Mortality among mallard ducklings exposed to both PCB and DHY, DHV only, or neither agent. (<i) 100 ppm PCB + DHV; (6) 50 ppm PCB ^ DHV; (c) 25 ppm PCB -f DHV; (rf) DHV control: and (e) untreated control. Dotted portion of lines prior to 47 hours and between 62 and 70 hours represent period* during which no observations were made. -- - tcntional effects of sublethal conccntra- . lions of chemical pollutants which are . - often alluded to, but rarely documented. It also emphasizes the real differences Rcrtnen aad Natu that exist between "sublethal" and "no effect" concentrations of pollutants. To the best of our knowledge, other stud ies in vivo of the possible effects of ' organochiorine pollutants' on the ius- ceptibility of a vertebrate host to a viral agent have not been reported. Milton Friend < 6aniel O. Trainer Department of Veterinary Science, . University of Wisconsin, Madison 53706 ' .. 1. R. W. Rlsebrough, P. Rleche, D. B.Peakan, S. C. Herman, M. N, Kirvcn, Notun 220, 109S (1968). '1 2. C. A. Pennine, hut. Eng. Chtm. 22, |1M (1930). 2. S. Jansen, New Scl. 32, 612 (1966). 4. D. C. Holmes, J. H. Simmons, t. 0*0. Tattoo, Nature 216, 227 (1967); A. V. Holden and K. Mande. IUS., p. 1274; t. H. Koetnan. M. C. Tea Noever Da Brauw, R. H. DeVes, Hid. 221, 1126 (1969); S. Jensen. A. C. Johnels, M. Olssoo, G. Otlerlind, Ibid. 224. 247 (1969). 5. G. Widmark. t. Ait. Otfic. Afr. Chtm. 59, 1069 (1967); L. M. Reynolds, hull. Environ. Coulam. ToxIcoL 4. 128 (1969). CL P. P. Levine, In Dlttattt of Poultry, H. E. Bolster and L. H. Schwarts, Ed. (Iowa Stale ' Unhr. Presa, Amet, 1963), p. 818. - 7. M. Friend and D. O, Trainer. J. WlUUfo PIs, .. In press, 8 We thank the Max McGrasr Wlldlile Founda- Uoo (or supplyln8 mallards for this study. Sop. ,, potted In part by the Patuxent Wildlife Re* - search Ceater,- Bureau of Sport Fisberiaa and Wildlife. . . M July 1970; revised 16 October 1970 .lull m i ^piwwpiyrrTwiprn--in i DSW 282632 " ' "* UWWPRIIJ... "*( STLCOPCB4063961