A family is suing a pet store for having sold them an infected rodent which led to the death of their son.
Aidan Pankey, 10, passed when the pet rat gave him rat-bite fever in June 2013.
His grandmother had acquired the animal for the young boy so that the female rodent he already had would mate with the male rat.
Together, they picked out "Alex" at the Petco store in San Diego.
But only two weeks after bringing the pet home, Aidan came down with a serious illness and exhibited flu-like symptoms for two whole days. He died soon after.
The Centers for Disease Control and Prevention (CDC) was able to determine that rat-bite fever was behind his quick and sudden death.
Aidan's family filed against the animal store in February 2014 and blamed it for not testing the rats it sells.
On April 29, introductory statements made at the civil trial posited that Petco had the "knowledge" that it was selling potentially diseased rats and that people were falling ill, but did nothing about it.
Aidan's father, Andrew Pankey, explained to KFMB: "I'm fighting this case to protect some children because I don't want this to happen to another family. I still talk to him, tell him I love him -- that daddy is not going to give up."
So far in the case, Pankey's attorney has accused Petco and pet supplier Barney's Pets of being fully aware that some of the rats were infected but did nothing to warn customers about the danger, San Diego Union-Tribune reports.
Attorneys for the company asserted that Petco is unable to guarantee healthy and disease-free rats since it sells millions in its stores.
They further clarified that Petco warns customers of the potential dangers that come from owning a rat, and listed rat-bite fever, but the warning is stipulated in a form that passes along general instructions on how to care for a rat, Inside Edition reports.
A Petco attorney stated: "Petco warned about it. One thing Petco cannot do is change the nature of an animal."
The boy's family feels the form was inadequate and is seeking unspecified damages.
Aidan's mother had previously sued Petco but settled out of court before the case went to trial.
CDC officials say that people can contract rat-bite fever from the scratches or bites of infected rodents, which include gerbils, mice and rats -- or sometimes, simply touching the diseased animal.
The bacteria behind the disease can also be contracted via food or drink but cannot be spread person-to-person.
The disease is rarely fatal and penicillin is the standard effective treatment.
The health agency says people who handle rats constantly, or live in rat-infested buildings, are most prone to contracting the disease.
The health officials recommend that rat handlers wear protective gloves while cleaning cages, wash hands regularly and avoid touching their mouths after handling a rodent.