Short answer. Yes. Article 1575 of the Civil Code provides that the sale of animals suffering from contagious diseases is void. The law treats this not as a defective sale subject to rescission but as a void contract — one that has no legal effect from the start.
What the law says
The sale of animals suffering from contagious diseases shall be void. A contract of sale of animals shall also be void if the use or service for which they are acquired has been stated in the contract, and they are found to be unfit therefor.
Civil Code, Article 1575 — Void Sales of Animals. Read the full provision →
Contagious disease makes the sale void
Article 1575 of the Civil Code establishes a categorical rule: The sale of animals suffering from contagious diseases shall be void. This is a stronger consequence than the ordinary remedy for hidden defects, which typically gives the buyer a redhibitory action to rescind the sale. For animals with contagious diseases, the legislature chose to make the contract void outright. A void contract produces no legal effects from the beginning — it is as if the sale never happened. The buyer is entitled to recover the price paid, and the seller cannot retain it by arguing that the buyer accepted or used the animal.
The disease must exist at the time of sale
Article 1575 applies when the animal suffering from contagious diseases is sold. The disease must be present at the time the contract is made — an animal that was healthy at sale but contracted a disease afterward does not trigger the article. The buyer bears the burden of establishing that the contagious disease already existed at the time of the sale, not merely that the disease appeared afterward. If the disease was latent at the time of sale, manifesting only after delivery, the question is whether it was already present at the moment of contracting, even if not yet outwardly apparent.
A second ground: animal unfit for its stated purpose
Article 1575 also provides a second ground for voiding a sale of animals: A contract of sale of animals shall also be void if the use or service for which they are acquired has been stated in the contract, and they are found to be unfit therefor. This second ground depends on whether the purpose was expressly stated in the contract itself. If the buyer and seller included in the contract the specific use or service the animal was to perform — farm labor, breeding, transport — and the animal turns out to be unfit for that purpose, the sale is void on this separate ground. An unstated purpose does not trigger this provision; the unfitness must correspond to a purpose written into the agreement.
Practical implications for the buyer
If you bought an animal that had a contagious disease at the time of sale, the contract is void, and you are not limited to ordinary warranty remedies. You should not have to prove that the seller acted in bad faith or knew of the disease — the voidness arises from the fact of the disease, not from the seller's knowledge of it. The practical consequence is that the seller must return the price and you return the animal. If the animal has already died or spread the disease to other animals in your possession, the damages consequences go beyond the mere return of the price, though that analysis depends on the surrounding circumstances of your particular situation.