The father of a 6-year-old Florida boy who died after trying to save a rabid bat said he's "never loved anyone or anything more."

The sick bat scratched Ryker Roque after his father, Henry Roque, discovered it in a bucket a few weeks ago, the father told ABC affiliate WFTV.

Ryker, who did not initially exhibit symptoms, began hallucinating and was rushed to a local hospital where a revolutionary treatment called "the Milwaukee protocol" proved unsuccessful. Ryker died on Sunday.

The method, developed by Rodney Willoughby of the Children's Hospital of Wisconsin, requires antiviral drugs be administered during a chemically induced coma. The technique has saved at least two U.S. children and 18 people worldwide since Willoughby created it in 2004, said Evan Solochek, a spokesman for the hospital.

Officials could not confirm what happened to the bat.

Once rabies symptoms appear, survival is extremely rare.

The Florida Department of Health declined to provide specific details on Ryker's death but said in a statement that it "confirmed a single human case of rabies that was likely transmitted when an individual was bitten by a bat and did not receive post-exposure prophylaxis. Unfortunately, the individual did pass away."

"It is important to avoid direct contact with wildlife," the statement continued. "If you believe you may have been exposed to rabies, contact your health care provider and your county health department immediately. If an exposure occurred, it is important to administer treatment right away."

The region experienced a similar case in October 2017, said Kent Donahue, a spokesman for the Florida Department of Health. That person, a resident of Highlands County, also died after being bitten by a bat and not immediately seeking medical attention.

"I am only aware of these two cases," Donahue said in an email.

Preventative medicine has "has proven nearly 100 percent successful" in eradicating U.S. rabies deaths, which declined to one or two annually in the 1990s from about 100 in 1900, according to the Centers for Disease Control and Prevention. An estimated 40,000 to 50,000 people are treated every year for rabies.

In 2015, wild animals accounted for more than 92 percent of reported rabies cases, mostly bats and raccoons, according to the CDC.

Rabies occurs in more than 150 countries and territories, according to the World Health Organization.

"In the Americas, bats are now the major source of human rabies deaths as dog-mediated transmission has mostly been broken in this region," according to the WHO's website.

The Lake County Sheriff's Office in Florida does not intend to pursue any charges linked to Ryker's death.

"At this point, we have not looked into any of that -- it's awful enough," Maj. Chris DeLibro told ABC News. "The way I understood it was, the boy found the bat and thought they were going to help it."

ABC News' Kevin Kraus contributed to this report.