Document 82m2BxOxZKkJgzYM6dqq1exek

fl|*UVW^U mmgUIVM WIMIt Dock Hcpatidf Virnt o Abstract Ten-day-old mallard ducklings fed a polychlorinated biphenyl os concentrations Of 25, 50, and 100 parts per million 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 biphenyls (PCB) aloof with DDE fJ.J-dichJoro-2,2-bis(Khlorophenyl)ethane) are reported 10-day feeding trial, no birds died or became clinically ill, although duck lings in the group given 100 ppm PCB isolation units where they were main tained on PCB-free feed and water for 3 days before being' challenged - to be the most abundant of the chlo rinated hydrocarbon pollutants In the were noticeably hyperexciiable after day 3 as ware those in the 50-ppm with DHV. No birds died or became clinically ill during the interim period global ecosystem (/). Despite the fact that PCB's have been in wide use group 4 days after treatment. Body weiglus of birds receiving PCB between PCB feeding and virus chal lenge although two birds were lost from elneo 1930 (2), they remained eco logically Inconspicuous until 1966 when 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 aU but, a Swedish chemist reported their pres- than those fed the diet without PCB the untreated controls (birds not re once in the tissues of pike and other (Table J), The heaviest body weights ceiving either PCB or DHV) were in- ' wildlife (5). Since then, their presence occurred in birds fed the highest con oculated intraperiteneally with 15 ' has been /eported in additional wild centrations of PCB, and the'trend ap LDr* (^0 percent effective lethal dose life of Europe and North America (/, peared to be linear. Differences io body for docks) of DHV per bird. The d). These compounds are interesting because they are an important source weights among treatment means were first birds died about 47 hours after highly significant (F= 20.30, d.f. = inoculation. Mortality was recorded of interference in the chemical detec tion of DDT and iu metabolites (5) and 4, JJ9) when tested by analysis of hourly for the remainder of the MV covariance. No statistical comparisons hour experimental period with one ex because they are a potential hazard in between individual treatment means ception; there were no observation* be the environment; on a weight basis PCB were made, A similar analysis of liver tween hours 63 through 69. The onset preparations have been shown to have weights (determined as a percentage of of mortality in alt groups given PCB . an estradiol-degrading potential about final body weight) disclosed highly sig .plus DHV began nt least I lo 16 hours five limes that of />,/>'DDE or techni nificant differences among treatment before that in the control group treated cal grade DDT |l,U-lrichloro*2r2-bis- means (F = 5.82, d.f. = 4, 18). These with the virus only (Fig. I). In addi (pchtorophcny1)ciHune) (/). differences appeared to be within tion, mortality levels occurring among ' As part of an investigation of possi groups treated with PCB rather than PCB-plus-vims treatment group* at the ble interactions between orgnnochkmne between treated and untreated groups end of the experiment were significantly pollutants and infectious diseases, this (Table 1). The small sample sizes (N higher at (he .01 level of probability study was initiated to determine _ 3) necessitates caution in interpretation than for ducklings receiving the virua whether eny interaction, antagonistic or of liver weight data. No interpretation only (chi squares 7.49, d.f. a I). synergistic, occurs with PCB and duck of differences among body and liver There was no significant difference m' hepatitis virus (DHV) in mallards weights are offered at this time. mortality among ducklings receiving the (dnas pfalyrhynchos). different concentrations of PCB plus Four separate diets, three with PCB . and one without, of a standard duck starter ration were fed to groups of Table I. Final mean body and liver weighs of mallard ducklings after being fed PCS ' (Aroclor 1254, MoiiianUi, $t. Lout*) for US gay*. Numbers in parentheses arc lite number viriis (chi square = 3.79, d.f. = 2). No birds in the untreated group died (Table 2). 10-day-old mallard ducklings. The three PCB diets contained Aroclor 1254 (in a oom oil premix) concentrations cal culated to be 2S, 50, and 100 parts per of birds toed. The liver end body weighas were edimlcd by covariance fur a comma* Marling mean; the liver weight was determined hr percentage of body weight. The liital cio*- iro< did not receive either I'CU or DIIV. All birds that died during the experi ment had gross pathognomonic liver lesions, indicating typical duck hepa titis infection (6), No other gross million (ppm). These diets were fed lo five groups of 25 ducklings each, three principal and two control groups . (Table I). , All birds were leg-banded with colorcoded, numbered bands, weighed, and fad their respective diets for 10 days. Treatment PCU (ppm) PCB + DHV PCtt + DHV PC8 + DHV DHV control Control too SO 23 0 0 litKly weigh! U> 3X1.6(25) 36X.X (25) 332.X (25) 313.2(25) 509.6 (23) IJwr weigh! (a) 0.046 (9) .037 m .029 (5) .036 (4) .034 (91 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 lo be any relation between treat ment and the presence or absence of edema. Histological and residue analy- On day 11 each bd was weighed ' sis have not been completed at this again, and every fifth bird from each treatment group was killed. Tissues time. Twelve days after the experiment be The suggestions that PCB may render were collected for residue analysts, his tology, and liver weights. During the gan, birds were placed in cratcj and a host more susceptible to certain types transported approximately 5 miles to of infectious agents is the significant loverj 18 December 1970 M0NS 084965 SCIENCE, Vol. 170 finding In Ibis study. None of the cd,, ' . centratioiM of PCB fed resulted In de lectrWo chemical Intoxication even with the physical stresses of weighing, handling, confinement, and crowding during transportation, transportation ltH, or relocation In a different environ ment. However, when the atress of an Infectious agent was added, these sublethal concentrations appeared to in fluence the resulting mortality rates, causing two- to fourfold increases (14 percent among virus controls versus 35 to 65 percent among groups receiving PCB plus DHV) and reduced incuba tion lime (Pig. 1 and Table 2). Similar Increases In mortality were Obtained with other organochlorino compounds In our laboratory (7). In those studies 30-day-old mallard duck lines which had been fed sublethal con centrations of pjr'-DDT or dicidrin exhibited three- to ninefold increases jn mortality over that of DHV controls (& percent among virus controls versus ( IP to SP percent among groups receiv ing dlatdrin plus DHV, and 19 to 40 percent among groups receiving p,pf. DDT plus DHV). It is unlikely that In all these instances mortality in the DHV control groups would bo less than half that in any interaction group on the basis of chance alone. This study illustrates ono of the potenllonal effects of sublethal concentra tions of chemical pollutants which are often alluded to, but rarely documented. It also emphasises the real differences that exist between "sublethal" and Hno- offect" concentrations of pollutants. To the best of our knowledge, other stud ies In vivo of the possible effects of orgattoddorine pollutants on the sus ceptibility of a vertebrate host to a viral ngent have not been reported. a Milton Friend * Daniel* O. Trainer Deportment of Veterinary Science, University of Wisconsin* Madison 33706 Table 2. Mortality among mallard ducklings caused by DHV during an 10-hour experimental period. No observation* were made between 31 to 47 and S2 to 70 hour*. The AmI rwnmt did not receive either PCD or DHV. Treatment PCB + DHV PCB + DHV PCB + DHV DHV control Control PCB (ppm) 100 50 23 No. of deaths/ total temple S/ll 13/20 7/20 3/21 0/20 Mortality Percentage Onset (hours 1 44.4 11-47 3333.0 31-47 14J <2-70 0B Cessation (boon) 73 73 73 Fig. I. Mortality among mallard ducklings exposed to both PCB and DHV. DHV only, or neither spent. In) 100 ppm PCB 4- DHV; (b) SO ppm PCB + DHV; (c) 23 ppm PCB + DHV; (</) DHV control; and (r) untreated control. Dotted portion of lines prior to 47 hours and between 62 and 70 hours represent periods during which no observations were made. 1. ft. W. Rtttbrovsfc. P. ftteche, D. 1. Peahen, 8. G. Herman, M. N. KJrvea, N*un ttf, tore ~ ' X C. A. Pennine. M. #. Chem. U, lias (IWOL ' X 8. Jansen, New Set. 3L 812 (1#S4). 4, D. C. Hobnee, 1. H. Simmons, I. 0*0. Tenon. Warn* SIS, 2X7 <iW7)t A. V. HoMan na4 JC. Minds, tM., p. 1274; J. H. Koemm. M. C. Tan Noevar De Ereuw, II. H. DaVes. SU, 211, 11X4 <!> 8. lenten, A. O. Jobneh. M. Olsaen, O. Otterliad. JMd. 2X4. 247 (IMS). X O. Widmark, J. Am. Offe. Agr. Chrm. #, 104* (1W7); X. M. Reynolde. MmU. Xnvdmn. Comtmm. Tmileot. 4, IXS (INS). 4 P. P. Levine, in D/immi / Fomltry, H. B. Bthtw and L. H. Schvuis, Ed. (Iowa Stata Univ. Pres*. Arne*. 1HS). p. S)l. 7. M. Friend and D, O, Trainer. /, WlUUft Ob. 4 we thank the Max McGraw WlldRf# PoundsUen for tupphrla* maUardr for iMs study. Supported in part by tha Patuxent Wildlife Re. aarcb Canter, 8mi*m of Sport Fiabartoa and Wildlife. M hits t*75 reviaed IS October 1P70 . HONS 084966