CACI No. 429. Negligent Sexual Transmission of Disease
Judicial Council of California Civil Jury Instructions (2023 edition)
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429.Negligent Sexual Transmission of Disease
[Name of plaintiff] claims that [name of defendant] sexually transmitted
[specify sexually transmitted disease, e.g., HIV] to [him/her/nonbinary
pronoun]. [Name of defendant] may be negligent for this transmission if
[name of plaintiff] proves that [name of defendant] knew, or had reason to
know, that [he/she/nonbinary pronoun] was infected with [e.g., HIV].
New May 2017; Revised May 2020
Directions for Use
This instruction should be given with CACI No. 400, Negligence - Essential Factual
Elements. In a claim for negligent transmission of a sexually communicable disease,
the elements of negligence, duty, breach, and causation of harm must be proved.
(John B. v. Superior Court (2006) 38 Cal.4th 1177, 1188 [45 Cal.Rptr.3d 316, 137
P.3d 153].)
One has a duty to avoid transmitting an infectious disease if that person should have
known of the infection (constructive knowledge). (John B., supra, 38 Cal.4th at pp.
1190-1191.) While the existence of a duty is a question of law for the court, what a
person should have known is a question of fact.
It must be noted that in John B., the court limited its holding on constructive
knowledge to the facts of the case before it, which involved a couple who were
engaged and subsequently married; a defendant who was alleged to have falsely
represented himself as monogamous and disease-free, and who insisted the couple
stop using condoms; and a plaintiff who agreed to stop using condoms in reliance
on those allegedly false representations. The court did not consider the existence or
scope of a duty for persons whose relationship did not extend beyond the sexual
encounter itself, whose relationship did not contemplate sexual exclusivity, who had
not represented themselves as disease-free, or who had not insisted on having sex
without condoms. (John B., supra, 38 Cal.4th at p. 1193.) Therefore, this instruction
may not be appropriate on facts that were expressly reserved in John B.
Sources and Authority
• “[A] person who unknowingly contracts a sexually transmitted disease such as
herpes may maintain an action for damages against one who either negligently
or through deceit infects her with the disease.” (Doe v. Roe (1990) 218
Cal.App.3d 1538, 1543 [267 Cal.Rptr. 564].)
• “[T]o be stricken with disease through another’s negligence is in legal
contemplation as it often is in the seriousness of consequences, no different from
being struck with an automobile through another’s negligence.” (John B., supra,
38 Cal.4th at p. 1188, original italics.)
• “Because ‘ “[a]ll persons are required to use ordinary care to prevent others
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being injured as a result of their conduct” ’, this court has repeatedly recognized
a cause of action for negligence not only against those who have actual
knowledge of unreasonable danger, but also against those who have constructive
knowledge of it.” (John B., supra, 38 Cal.4th at p. 1190, internal citation
omitted.)
• “ ‘[C]onstructive knowledge,’ which means knowledge ‘that one using reasonable
care or diligence should have, and therefore is attributed by law to a given
person’, encompasses a variety of mental states, ranging from one who is
deliberately indifferent in the face of an unjustifiably high risk of harm to one
who merely should know of a dangerous condition. (John B., supra, 38 Cal.4th
at pp. 1190-1191, internal citations omitted.)
• “[T]he tort of negligent transmission of HIV does not depend solely on actual
knowledge of HIV infection and would extend at least to those situations where
the actor, under the totality of the circumstances, has reason to know of the
infection. Under the reason-to-know standard, ‘the actor has information from
which a person of reasonable intelligence or of the superior intelligence of the
actor would infer that the fact in question exists, or that such person would
govern his conduct upon the assumption that such fact exists.’ In other words,
‘the actor has knowledge of facts from which a reasonable man of ordinary
intelligence or one of the superior intelligence of the actor would either infer the
existence of the fact in question or would regard its existence as so highly
probable that his conduct would be predicated upon the assumption that the fact
did exist.’ ” (John B., supra, 38 Cal.4th at p. 1191, internal citations omitted.)
• “[W]e are mindful that our precedents direct us to consider whether a duty of
care exists ‘ “on a case-by-case basis.” ’ Accordingly, our conclusion that a claim
of negligent transmission of HIV lies against those who know or at least have
reason to know of the disease must be understood in the context of the
allegations in this case, which involves a couple who were engaged and
subsequently married; a defendant who falsely represented himself as
monogamous and disease-free and insisted the couple stop using condoms; and a
plaintiff who agreed to stop using condoms in reliance on those false
representations. We need not consider the existence or scope of a duty for
persons whose relationship does not extend beyond the sexual encounter itself,
whose relationship does not contemplate sexual exclusivity, who have not
represented themselves as disease-free, or who have not insisted on having sex
without condoms.” (John B., supra, 38 Cal.4th at p. 1193.)
Secondary Sources
6 Witkin, Summary of California Law (11th ed. 2017) Torts, § 1044
1 Levy et al., California Torts, Ch. 1, Negligence: Duty and Breach, § 1.13
(Matthew Bender)
33 California Forms of Pleading and Practice, Ch. 380, Negligence, § 380.32[2]
(Matthew Bender)
CACI No. 429 NEGLIGENCE
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16 California Points and Authorities, Ch. 165, Negligence, § 165.170 (Matthew
Bender)
NEGLIGENCE CACI No. 429
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