John & Mary Doe v. Baxter Healthcare , 380 F.3d 399 ( 2004 )


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  •                         United States Court of Appeals
    FOR THE EIGHTH CIRCUIT
    ___________
    No. 03-2651
    ___________
    John Doe; Mary Doe, as Parents and      *
    John & Mary Doe as Guardians on         *
    behalf of John Doe, Jr.,                *
    *
    Appellants,                *
    *          Appeal from the United States
    v.                               *          District Court for the
    *          Southern District of Iowa.
    Baxter Healthcare Corporation; Alpha *
    Therapeutic Corporation; Bayer          *
    Corporation,                            *
    *
    Appellees,                 *
    *
    Cutter Biological, a Division of Miles, *
    Inc.; Armour Pharmaceutical Company, *
    *
    Appellees.                 *
    ----------------------------------------
    John Doe; Mary Doe, as Parents and      *
    Guardians on behalf of John Doe, Jr.;   *
    John Doe, Jr.,                          *
    *
    Appellants,                 *
    *
    v.                               *
    *
    Cutter Biological, a Division of Miles, *
    Inc.; Armour Pharmaceutical Company; *
    Des Moines Plasma Center, Inc.;        *
    Siouxland Plasma Center, now known as*
    Gagnard and Marceaux, Sioux City, Inc.,*
    *
    Appellees.                 *
    ___________
    Submitted: April 15, 2004
    Filed: August 24, 2004
    ___________
    Before MORRIS SHEPPARD ARNOLD, MAGILL, and MURPHY, Circuit Judges.
    ___________
    MAGILL, Circuit Judge.
    Plaintiff-Appellants, John and Mary Doe (collectively, "the Does"), sued the
    Defendant-Appellees, Armour Pharmaceutical Company ("Armour"), Alpha
    Therapeutic Corporation ("Alpha"), Baxter Healthcare Corporation ("Baxter"), and
    Bayer Corporation, f/k/a Cutter Biological ("Cutter"), in two separate actions in Iowa
    state court. They claimed that one of the defendants had negligently caused their son,
    John Doe, Jr. ("Doe Jr.") to become infected with Human Immunodeficiency Virus
    ("HIV") by allowing a product they knew carried a risk of infection to remain on the
    market. Doe Jr. is a hemophiliac who has received various treatments for the disease,
    including infusions of Factor VIII concentrate, which the defendants produced.
    This case presents three issues, all of which turn on whether the Does have
    presented evidence sufficient to create a genuine question of fact regarding who
    caused Doe Jr. to be infected with HIV. The first issue is whether, under traditional
    negligence, the Does have presented enough evidence that any single defendant was
    the but-for cause of Doe Jr.'s infection. The second issue is whether, under
    alternative liability, the Plaintiffs have presented enough evidence that the four
    defendants together are the only ones who could be responsible for Doe Jr.'s
    -2-
    infection. If the four defendants are the only possible tortfeasors, then the Does argue
    that each defendant has the burden of proving that it did not cause Doe Jr.'s injury.
    The third issue is whether the Does can sustain a civil conspiracy cause of action
    against the defendants. The resolution of this last issue turns on the resolution of the
    first two issues; if the Does have created a genuine question of fact regarding
    causation, then their civil conspiracy claim may go forward. The district court ruled
    against the Does on all three issues, and the Does appeal.
    The district court had diversity jurisdiction to hear this case under 
    28 U.S.C. § 1332
    . This court has jurisdiction over the appeal under 
    28 U.S.C. § 1291
    . We
    affirm.
    I.
    A. Factual Background
    John Doe, Jr. was born on September 24, 1978. At ten months, physicians
    diagnosed him as suffering from Hemophilia A, which results from a deficiency in
    the production of a blood factor component known as "Factor VIII." Lack of Factor
    VIII stops the blood from coagulating normally.
    There are various ways to treat Hemophilia A, and Doe Jr. has undergone
    several of them at various times. The disease may be treated by supplementing levels
    of the Factor VIII protein through infusions of whole blood, plasma, cryoprecipitate,
    and Factor VIII concentrate. From November 24, 1979 to April 27, 1981, Doe Jr.
    received cryoprecipitate infusions. Cryoprecipitate is the precipitate that forms when
    plasma is frozen and then thawed. It is rich in Factor VIII, but contains other
    components of the source plasma. Each cryoprecipitate treatment comes from a small
    number of donors. According to one of the Does' experts, the cryoprecipitate used
    in Iowa at the time was locally procured from single donors. On May 19, 1980, Doe
    -3-
    Jr. received his first infusion of Factor VIII concentrate. Factor VIII concentrate is
    made from pooled human plasma from many different donors from across the
    country. Manufacturers separate components of the plasma and isolate the Factor
    VIII protein for use in the therapy. Factor VIII concentrate is made from the plasma
    of hundreds or thousands of donors, so the number of donors in any single dose is
    quite large. Doe Jr. continued to receive Factor VIII concentrate infusions
    manufactured by various companies until January 1985. After that month, he
    received only heat-treated Factor VIII concentrate or monoclonal factor concentrates.
    Neither of these last methods of treatment carry any risk of HIV infection. The heat-
    treatment destroys the HIV virus, and monoclonal factors are derived from non-blood
    sources that cannot carry the disease.
    Doe Jr. tested positive for HIV in July 1987. The parties agree that his infection
    occurred during a single infusion, and that it is not possible to identify which
    particular infusion caused his infection. Instead, the Does attempted to establish,
    using expert testimony, the period during which Doe Jr. was infected. They presented
    expert testimony that Doe Jr. received treatments that exposed him to some risk of
    HIV exposure beginning in November 1979 and continuing through January 1985.
    There is evidence that the risk of exposure from cryoprecipitate treatments between
    November 1979 and May 1981 was very low. They also presented expert testimony
    that Doe Jr.'s risk of exposure greatly increased when he began receiving treatments
    of Factor VIII concentrate on May 19, 1980. The Does also offered evidence that
    Doe Jr. was not infected by a heat-treated Factor VIII concentrate treatment or a
    monoclonal concentrate treatment.1 According to medical records, this places the
    date of Doe Jr.'s infection between 1979 and January 1985, the period during which
    Doe Jr. received cryoprecipitate treatments and Factor VIII concentrate treatments
    that had not been heat-treated. The Does spend much of their effort trying to
    1
    The defendants agree that Doe Jr. could not have been infected once he began
    treatment using heat-treated concentrate and monoclonal concentrate.
    -4-
    establish which defendants supplied the Factor VIII concentrate between May 1980
    and January 1985. Although they have named the relevant suppliers of Factor VIII
    concentrate, they have not named the manufacturers of the cryoprecipitate as
    defendants.
    The Does rely on hospital records that indicate the source of the concentrate
    with which Doe Jr. was treated. According to those records, Doe Jr. received Factor
    VIII concentrate prescriptions from three manufacturers: Cutter, Armour, and Alpha.
    The evidence indicates he received nineteen prescriptions from May 1980 to
    November 1984. He received two prescriptions for Alpha products, on May 20, 1980
    and June 15, 1980. Except for those two dates, all Doe Jr.'s prescriptions from May
    1980 to September 6, 1983 were for Cutter's factor concentrate. Thereafter, from
    December 2, 1983 to November 19, 1984, Doe Jr. used the factor concentrate
    manufactured by Armour. Complicating this issue, the Does' experts contend that the
    records are incomplete. They estimate that he received many more doses of Factor
    VIII concentrate than the surviving records reflect.
    The Does' expert medical testimony further limits the dates of possible
    infection. They presented statements by four experts. James Mosley, M.D., asserted
    that Doe Jr. was infected after the middle of 1983. William Robinson, M.D., opined
    that he was infected around February 1983. Roger Grimson, Ph.D., was of the
    opinion that Doe Jr. was infected in or after August 1983. Finally, Robert Remis
    provided probabilities of infection for each relevant year. He said that there was a
    65% chance that Doe Jr. was infected between 1983 and 1985. He also said there was
    a 5% chance of infection in 1980, 5% in 1981, and 25% in 1982.2 The defendants
    2
    Defendants claim that Doe Jr.'s physician, Thomas Kisker, M.D., gave expert
    testimony indicating his opinion was that Doe Jr. was infected in the fall of 1982.
    This position differs from the opinions of the Does' other experts. However, Dr.
    Kisker was not recognized by the district court as a qualified expert; he testified as
    Doe Jr.'s personal physician. As he noted in his testimony, an "infection disease
    -5-
    presented their own experts, who asserted that the infection probably occurred before
    August 1982.
    In addition, the Does have presented an expert's declaration asserting that
    Alpha, Armour, Baxter, and Cutter were the only players in the Factor VIII
    concentrate market in Iowa at the relevant time. The expert's declaration states the
    four named defendants in this case "had 94.5% of the national Factor VIII market in
    1980 . . . , 93% of the national Factor VIII market in 1982 . . . , and 88% of the market
    in 1984." Summ. J. App. at A-204.3 The same declaration indicates that the other
    purported market players did not distribute to Iowa during the relevant period.
    Defendants claim they have presented contrary evidence that shows they were
    not the only manufacturers in the market at the time Doe Jr. was using Factor VIII
    concentrate. They represent to the court that there were seven other market players
    at the time: the American Red Cross ("Red Cross"); Abbott Laboratories ("Abbott");
    New York Blood Center; Scripps Laboratories ("Scripps"); Parke-Davis; Squibb; and
    Michigan State Laboratories. This claim is almost entirely unsupported by the record
    citations defendants have provided. For every purported market player except the
    Red Cross, the defendants rely for their claims solely on the depositions of Fred
    Feldman and Allan Brownstein. Dr. Feldman, however, represents only that certain
    other manufacturers were in the business of making factor concentrate in late 1974.
    His testimony is unhelpful. Brownstein is perhaps less helpful still. Brownstein gave
    person" would better be able to answer questions regarding the precise date of Doe
    Jr.'s infection. Summ. J. App. at A-101. The Does' other experts dismissed his
    estimate as based on false premises.
    3
    Apparently there was some controversy over the timing of this expert report.
    The district court noted that there was some question whether the expert's report
    would be admitted. Doe v. Baxter Healthcare Corp., 
    178 F. Supp. 2d 1003
    , 1014
    (S.D. Iowa 2001). The court did not resolve this issue, however, and the defendants
    do not press it on appeal.
    -6-
    testimony that some other companies were producing Factor VIII concentrate in the
    late 1970s. It is clear from his deposition transcript that his memory is limited, and
    he makes no representations regarding production in the 1980s or these companies'
    distribution of their product. Thus, defendants point to no evidence that other
    companies were in the Factor VIII concentrate market during the early to middle
    1980s.
    The most important factual dispute concerns whether the Red Cross provided
    some Factor VIII concentrate to Doe Jr. during the period before 1985. The Does
    admit that on one occasion they obtained Factor VIII concentrate distributed to the
    University of Minnesota by the Red Cross. What are contested are the dates of these
    purchases. The dates are important because, as of 1985, the Red Cross distributed
    only heat-treated Factor VIII concentrate, which the parties admit cannot transmit
    HIV. The Does provide conflicting evidence on this point. Mrs. Doe testified in her
    deposition that she believed that she purchased the Red Cross factor concentrate
    before 1985. Summ. J. App. at A-24. However, in a later declaration, Mrs. Doe
    stated that she had reviewed her records and they refreshed her recollection that she
    purchased the Red Cross factor concentrate in 1985. The Does include as support
    copies of the records of their son's treatment at the University of Minnesota. The
    records confirm that he began treatment at the University of Minnesota on June 10,
    1985. Thus, viewing the facts in the light most favorable to the Does, it appears that
    Mrs. Doe's earlier testimony was mistaken, and Doe Jr. did not receive factor
    concentrate from the Red Cross until after they had begun heat-treating their product.
    In addition, the Does presented evidence that all four defendants conspired to
    keep factor concentrate they knew to be contaminated with HIV on the shelves after
    they had decided to change their production method to eliminate the risk of infection.
    The district court ruled that the Does had presented sufficient evidence to survive
    summary judgment on that claim, provided that negligence could be the underlying
    offense. Later, the Iowa Supreme Court held, in answer to a certified question in
    -7-
    another case, that negligence can be the underlying offense upon which a civil
    conspiracy claim is based. The defendants do not challenge the sufficiency of the
    Does' evidence that there was a conspiracy, but instead seek to avoid liability for civil
    conspiracy on the ground that the Does cannot establish that any single defendant
    caused Doe Jr.'s injury and thus cannot establish that there was an underlying tort.
    B.    Procedural Background
    The Does filed two negligence actions in Iowa state court in 1996. The
    defendants removed them to the United States District Court for the Southern District
    of Iowa based on diversity jurisdiction. The Judicial Panel on Multidistrict Litigation
    transferred the cases to the United States District Court for the Northern District of
    Illinois for coordinated pretrial proceedings. In 1999, the cases were sent back to the
    Southern District of Iowa. After discovery, the defendants sought summary judgment
    on the basis that the Does could not establish causation and that in Iowa a civil
    conspiracy claim cannot be predicated upon an underlying negligence claim. The
    district court granted summary judgment on the negligence claims, holding that the
    Does had failed to create a genuine issue of material fact on the question who caused
    Doe Jr.'s infection. The district court withheld judgment on the civil conspiracy claim
    because the Iowa Supreme Court had before it a certified question in another case.
    In Wright v. Brooke Group Ltd., 
    652 N.W.2d 159
     (Iowa 2002), the Iowa Supreme
    Court held that plaintiffs can base a civil conspiracy claim on a non-intentional
    underlying tort. On June 3, 2003, the district court granted defendants' motion for
    summary judgment on the alternate basis that the Does could not establish the
    underlying tort. The Does timely appealed.
    II.
    This court reviews the district court's grant of summary judgment de novo.
    Dico, Inc. v. Amoco Oil Co., 
    340 F.3d 525
    , 528-29 (8th Cir. 2003). Summary
    -8-
    judgment is appropriate only where no genuine issue of material fact exists and the
    moving party is entitled to judgment as a matter of law. Anderson v. Liberty Lobby,
    Inc., 
    477 U.S. 242
    , 250 (1986). The party opposing summary judgment "'must
    present more than a scintilla of evidence and must advance specific facts to create a
    genuine issue of material fact for trial.'" Dico, 
    340 F.3d at 529
     (quoting F.D.I.C. v.
    Bell, 
    106 F.3d 258
    , 263 (8th Cir. 1997)).
    III.
    The Does first claim that the district court erred by dismissing their claim under
    a traditional negligence theory of liability. We must decide whether the Does
    presented enough evidence respecting which one defendant caused Doe Jr. to become
    infected with HIV to allow a jury to impose liability. The Does presented evidence
    that shows Doe Jr. was infected between 1979—when he started using
    cryoprecipitate—and January 1985—when he started using a safe, heat-treated
    version of Factor VIII concentrate. They also presented expert testimony stating that
    the infection most likely occurred during 1982, 1983, or 1985. The Does also
    presented evidence that they used the Factor VIII concentrate product of three of the
    named defendants: Armour, Alpha, and Cutter.4 All parties agree that there is no way
    to determine the precise injection that infected Doe Jr.5 The only evidence that can
    distinguish the three defendants are the dates Doe Jr. used their products and the
    expert statements regarding the date of infection.
    4
    The Does concede that they do not have a claim in traditional negligence
    against defendant Baxter because they have no evidence that Doe Jr. used a Baxter
    product. They maintain their claims against Baxter only under the alternative liability
    theory and the civil conspiracy charge.
    5
    In some cases of HIV infection, the event of infection is followed shortly by
    an illness that experts may use to infer the date of infection. The parties agree that
    Doe Jr. did not exhibit an incidental illness of this sort.
    -9-
    A defendant's breach of its duty of care is actionable negligence only if the
    breach is the proximate cause of a plaintiff's injury. Cedar Falls v. Cedar Falls Sch.
    Dist., 
    617 N.W.2d 11
    , 17 (Iowa 2000). Proximate cause has two elements: "(1) the
    defendant's conduct must have in fact caused the damages; and (2) the policy of the
    law must require the defendant to be legally responsible for them." 
    Id.
     To establish
    the first element of proximate causation, the Does must show that their son's damages
    would not have occurred but-for a defendant's negligence. 
    Id.
    The Does' claim founders on the shoals of the but-for requirement, for it is
    conceded by the Does that there is no way to identify the moment of infection. The
    best they can hope to do is narrow the potential dates and show which companies
    provided the product during that period. Their experts have not narrowed the
    potential dates of infection so far that a rational jury could conclude that the conduct
    of one of the defendants was the but-for cause of Doe Jr.'s infection. The best that
    can be said for the evidence is that there is a strong likelihood that either Cutter or
    Armour supplied the Factor VIII concentrate that infected Doe Jr. But the evidence
    provides no means of distinguishing between these two defendants. Consequently,
    even taking the expert statements proffered by the Does as true, a jury would be
    required to speculate in order to find one of the defendants liable for Doe Jr.'s
    damages.
    The Does argue that the court should not require them to prove any single
    defendant was a but-for cause. They argue for the lesser standard articulated by the
    Iowa Supreme Court in Huber v. Watson, 
    568 N.W.2d 787
     (Iowa 1997). That court
    held that "[i]n cases involving exposure to asbestos, 'a reasonable inference of
    exposure to a defendant's asbestos-containing product, coupled with expert testimony
    regarding asbestos fiber drift and the cumulative effects of exposure to asbestos, is
    enough to prove proximate cause.'" 
    Id. at 790
     (quoting Beeman v. Manville Corp.
    Asbestos Disease Comp. Fund, 
    496 N.W.2d 247
    , 254 (Iowa 1993)). The "test is
    whether a jury could logically make the necessary inference of the causal connection
    -10-
    between defendant's action and the plaintiff's injury." 
    Id.
     Under this standard, the
    Does argue, the evidence would support a jury verdict in their favor because their
    expert testimony narrows the range of possible dates of infection and would allow a
    jury to base its judgment on probability judgments of experts that one defendant or
    another was a substantial cause of Doe Jr.'s injuries.
    The Does' reliance on Huber's reasoning is misplaced. Huber and all the cases
    upon which it relies concern liability for injuries caused by asbestos exposure. The
    crucial difference between asbestos exposure and exposure to HIV is that the effects
    of asbestos exposure are cumulative. Hence, incidents of asbestos exposure are
    concurrent causes of a plaintiff's injuries. The parties and experts all admit that HIV
    infection does not work in the same way. Doe Jr. was infected on a particular
    occasion. Doe Jr.'s separate infusions were not concurrent causes of his HIV
    infection. Plaintiffs are relieved of the need to show that a defendant was a but-for
    cause of an injury only where the "conduct of two or more persons 'is so related to an
    event that their combined conduct, viewed as a whole, is a but-for cause of the event,
    and the application of the but-for rule to them individually would absolve all of
    them.'" Spaur v. Owens-Corning Fiberglass Corp., 
    510 N.W.2d 854
    , 858 (Iowa 1994)
    (quoting W. Page Keeton, Prosser and Keeton on the Law of Torts § 41, 268 (5th ed.
    1984)). Since the parties admit that concurrent causation is not at issue in this case,
    the Does are not relieved of the need to distinguish between the defendants and show
    that one was the but-for cause of Doe Jr.'s infection.
    Accordingly, we will affirm the district court's determination that the Does
    cannot sustain their claim under traditional negligence.
    IV.
    The Does seek to have this court apply a widely accepted exception to the
    requirement that they prove which negligent defendant caused Doe Jr. to be infected
    -11-
    with HIV.6 Under an alternative liability approach to causation, the plaintiff still must
    show that one of the defendants caused his injury, but "the burden of proof as to
    which actor caused the harm shifts to the defendants because there is uncertainty as
    to which of them caused the injury." Mulcahy v. Eli Lilly & Co., 
    386 N.W.2d 67
    , 72
    (Iowa 1986). If the court found alternative liability applicable, it would not matter
    that the plaintiffs cannot pinpoint the date of infection or the manufacturer which
    supplied the tainted Factor VIII concentrate. Instead, the plaintiffs might prevail on
    summary judgment if they can create a genuine question of material fact whether only
    the named defendants could have caused Doe Jr. to contract HIV, even if they cannot
    show which one of the defendants did so.
    We begin by considering whether it is appropriate under Iowa law to apply the
    alternative liability theory at all. Under diversity jurisdiction and applying Iowa law,
    we must endeavor to decide the case as the Iowa Supreme Court would decide it.
    Rucci v. City of Pacific, 
    327 F.3d 651
    , 652-53 (8th Cir. 2003). We are bound by the
    decisions of the Iowa Supreme Court. 
    Id. at 652
    . Where the Iowa Supreme Court has
    not addressed an issue, we must determine what rule the Iowa Supreme Court would
    apply. 
    Id. at 652-53
    . Statements made by the Iowa Supreme Court are instructive.
    So, too, are rulings by inferior state appellate courts. 
    Id. at 653
    .
    The Iowa Supreme Court has neither adopted the alternative liability theory nor
    ruled it out, so we are faced with predicting whether that court would apply
    alternative liability in this case. There are no Iowa Court of Appeals decisions on the
    topic. However, the Iowa Supreme Court did discuss the theory of liability at some
    length in Mulcahy, 
    386 N.W.2d at 72-74
    . In that case, the Supreme Court faced a
    6
    The exception had its origin in the California Supreme Court decision in
    Summers v. Tice, 
    199 P.2d 1
     (Cal. 1948). It has been followed by courts in several
    states in the context of product liability suits. See, e.g., McGuinness v Wakefern
    Corp., 
    608 A.2d 447
     (N.J. 1991); Minnich v. Ashland Oil Co., Inc., 
    473 N.E.2d 1199
    (Ohio 1984); Abel v. Eli Lilly & Co., 
    343 N.W.2d 164
     (Mich. 1984).
    -12-
    certified question from a federal district court asking whether it would adopt three
    nontraditional theories of tort liability on certain established facts. While the Iowa
    Supreme Court did not, in the end, adopt a position on alternative liability, the case
    bears close attention for its detailed discussion of nontraditional theories of
    negligence.
    The product under review in Mulcahy was a synthetic estrogen compound
    known as DES. 
    Id. at 69
    . DES causes injury to children still in the womb when
    ingested by their mothers. DES can also cause difficulties for the grandchildren of
    women who took the drug. As a consequence, victims of DES did not recognize they
    had been injured until years—and in some cases decades—later. Plaintiffs in DES
    lawsuits seldom could present evidence concerning the manufacturer of the particular
    doses their mothers or grandmothers took. At the time of concern in Mulcahy, there
    were some 200 manufacturers and distributors of DES nationally. The Mulcahy
    plaintiffs sought to establish liability by appealing to three different
    theories—alternative liability, enterprise liability,7 and market share liability. The
    court held that neither alternative liability nor enterprise liability applied on the facts
    before it. Its treatment of market share liability, however, was more direct and more
    hostile.
    The Iowa Supreme Court rejected the market share liability theory on broad
    policy grounds. Under market share liability, as fashioned by the California Supreme
    Court in Sindell v. Abbott Laboratories, 
    607 P.2d 924
     (Ca. 1980), a plaintiff need not
    join all potential defendants to benefit from burden shifting. There need be no
    7
    Enterprise liability has the following elements: (1) the product that caused the
    injury was manufactured by one of a few defendants; (2) the defendants all knew of
    the risks the product posed and together had the ability to reduce those risks; and (3)
    the defendants failed to take those steps, choosing instead to push responsibility for
    taking action onto a trade association. See, e.g., Burnside v. Abbott Laboratories, 
    505 A.2d 973
    , 984 (Pa. Super. Ct. 1985). Enterprise liability is not at issue in this case.
    -13-
    assurances whatsoever that the defendants who actually end up paying damages for
    an injury played any role in causing the injury. A plaintiff must only join
    manufacturers of a substantial share of the product and meet her burden of proof on
    the other negligence elements. The burden then shifts to the defendants to prove they
    could not have issued the particular product that caused the injury. For any
    defendants who fail to meet their burden, the court "fashions a 'market share' theory
    to apportion damages according to the likelihood that any of defendants supplied the
    product by holding each defendant liable for the proportion of the judgment
    represented by its share of that market." Mulcahy, 
    386 N.W.2d at 75
     (quotation
    omitted). The Iowa Supreme Court objected that all this theory requires of a plaintiff
    is proof of negligence "in the air," and held that such would not suffice. 
    Id. at 76
    .
    The link between the defendant and the injurious act under the market share theory
    is too attenuated.
    The alternative liability theory does not exhibit the same faults as the market
    share liability theory. The Iowa Supreme Court treated the alternative liability theory
    less dismissively, holding only that it did not apply under the facts as presented. The
    court noted that one version of the alternative liability theory "still requires plaintiffs
    to prove they have been harmed by the conduct of one of the defendants." 
    Id. at 74
    .
    Thus, there is a closer link between tortfeasor and injury under alternative liability
    than under market share liability. The plaintiff under alternative liability has the
    burden of narrowing the field of potentially liable defendants to "'all the actors who
    may have caused the injury in fact.'" 
    Id.
     (quoting Abel v. Eli Lilly & Co., 
    343 N.W.2d 164
    , 173 (Mich. 1984)). According to the Iowa Supreme Court, "[p]laintiffs
    also have the burden of showing that all the defendants have acted tortiously, and that
    plaintiffs, through no fault of their own, are unable to identify which actor caused the
    injury." Mulcahy, 
    386 N.W.2d at 74
    . Only at this point does the burden shift under
    alternative liability, requiring defendants to prove they did not manufacture the
    injurious product. Thus, under alternative liability, the plaintiffs have a much stiffer
    burden than under market share liability, and the difference addresses the precise
    -14-
    concerns the Iowa Supreme Court expressed in rejecting market share liability.
    Plaintiffs may not simply prove negligence is "in the air," but rather must target all
    the companies that might have been liable and prove that each had a duty of care that
    it breached. This rule is a far cry from market share liability, which simply apportions
    liability to market actors who cannot prove they did not cause a particular injury.
    While we think, based on Mulcahy, that the Iowa Supreme Court would adopt
    the alternative liability theory and give it the contours discussed in that case if
    presented with the right facts, we need not decide that issue because we do not
    believe that it would do so on the facts here presented. To hold the theory applies,
    we would have to hold that the district court erred in determining that the Does did
    not succeed in presenting enough evidence that they had brought all potential
    defendants to court. The district court held that the Does' claim fails because they did
    not negate the manufacturers of the doses of cryoprecipitate as potential defendants.
    To do so, they would have to have presented enough evidence to convince a rational
    jury that the cryoprecipitate manufacturers could not have caused Doe Jr.'s injury. It
    is not sufficient that they present enough evidence to convince a rational jury that the
    cryoprecipitate manufacturers did not cause his injury. The defendants also argue that
    the Does cannot prevail for the additional reason that Doe Jr. received Factor VIII
    concentrate treatments manufactured by the Red Cross and that the Does did not
    negate these doses as the cause of Doe Jr.'s infection. In our view, it is only the Does'
    failure to exclude the manufacturers of cryoprecipitate as potential defendants that is
    fatal to their claim.
    The Does have presented sufficient evidence to convince a rational jury that the
    Red Cross-manufactured Factor VIII concentrate could not have infected Doe Jr. In
    Mulcahy, the Iowa Court held that alternative liability could not apply because
    "[plaintiffs] do not possess evidence to negate marketing of DES in Ames by other
    manufacturers." 
    Id. at 74
    . The Does, unlike the plaintiffs in Mulcahy, have
    substantial evidence that the Factor VIII concentrate manufactured by the Red Cross
    -15-
    did not cause their son's infection. This feature of the case distinguishes it from
    Mulcahy and supports allowing the plaintiffs to go forward on an alternative liability
    theory. Defendants rely on Mrs. Doe's deposition testimony claiming that her son
    received a non-heat-treated infusion of Factor VIII concentrate from the Red Cross
    before 1985. If true, the treatment would be a potential source of the infection.
    However, Mrs. Doe has since reviewed the medical records from the University of
    Minnesota, where the Red Cross treatment occurred, and determined that she was
    mistaken about the date. The Does have provided their son's records from the
    University of Minnesota, and they confirm that he first received treatments there in
    1985, after the Red Cross started heat-treating its Factor VIII concentrate.
    Consequently, on both these points the Does have presented evidence sufficient for
    a rational jury to conclude that the Red Cross could not have caused Doe Jr.'s
    infection. The defendants are not entitled to summary judgment on this basis.
    The Does have not, however, met their burden under the summary judgment
    standard with respect to Doe Jr.'s cryoprecipitate treatments. The district court
    properly determined that the Does' evidence that Doe Jr.'s cryoprecipitate treatments
    could not have caused his infection was insufficient as a matter of law. The facts
    related to these treatments are sparse. Doe Jr. received several treatments with
    cryoprecipitate between November 24, 1979 and April 27, 1981. On May 19, 1980,
    Doe Jr. began using Factor VIII concentrate, and by April 27 the next year, he made
    the switch permanent. Unlike factor concentrates which result from blending
    multiple donor samples together, cryoprecipitate is made from the blood of a very few
    donors. Thus the risk posed by any use of cryoprecipitate is much lower than that
    posed by an application of factor concentrate. The treatments are not without risk,
    however. The Does presented an expert declaration by Dr. Donald Francis, M.D.,
    which briefly addressed the likelihood that Doe Jr. was infected by cryoprecipitate.
    According to Dr. Francis, the cryoprecipitate posed "very little" risk of infection to
    Doe Jr. Presumably based in part on this same view of the risk posed by the
    cryoprecipitate treatments, other experts testified that Doe Jr.'s infection most likely
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    occurred after he stopped receiving those treatments. This is the sole evidence
    provided to negate the cryoprecipitate as the agent of Doe Jr.'s infection. The experts'
    proposed testimony cannot negate the manufacturers of the cryoprecipitate as the
    actors who caused Doe Jr.'s infection; it can only cast strong doubt on them as
    culprits. Mulcahy requires that plaintiffs clear a much higher hurdle. While it is
    evident that the Does have created a genuine question of fact that the cryoprecipitate
    treatments did not cause Doe Jr.'s infection, they have not created a genuine question
    of fact that they could not have caused the infection, which is the standard favored
    in Mulcahy. It is a difficult standard to meet, but it is the cost of avoiding proof that
    some particular, single defendant was the but-for cause of Doe Jr.'s injury under Iowa
    law. We believe the Iowa Supreme Court favors a rule that keeps liability for
    negligence moored closely to causation, as its discussion renouncing market share
    liability makes clear. Accordingly, we cannot say that the Does have created a
    genuine question of material fact as to whether all the potential defendants have been
    named, and we affirm that aspect of the district court's order.
    V.
    The Does also appeal the district court's separate order granting summary
    judgment in favor of all defendants on the Does' civil conspiracy claim. Given our
    conclusion that the Does did not present enough evidence that any single defendant
    caused Doe Jr.'s injury, it follows that the district court properly dismissed the civil
    conspiracy claim as well. A civil conspiracy is an agreement between two or more
    people to commit a wrong against another person. Wright v. Brooke Group Ltd., 
    652 N.W.2d 159
    , 172 (Iowa 2002). The conspiracy alone is not actionable. 
    Id.
     Only acts
    taken in furtherance of the conspiracy that cause some injury to the plaintiff can be
    the basis of a civil conspiracy claim. 
    Id.
     The district court held that the Does had
    presented sufficient evidence of a conspiracy involving the defendants to withstand
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    summary judgment. But, as we held above, they have not presented sufficient
    evidence that any of the defendants actually caused Doe to become infected with
    HIV. Without such evidence, the Does' civil conspiracy claim sinks as well.
    VI.
    For the reasons provided above, we affirm the decision of the district court in
    all respects.
    ______________________________
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