New Rabies Risk: Cats in Yucatan Endanger Humans

Cats are emerging as a new concern in the fight against rabies in Yucatan, Mexico. This is due to a combination of factors including rabies vaccination campaigns primarily targeting dogs, the practice of rescuing stray animals, and the encroachment of the Yucatan population into forested areas. This increases the risk of wild mammals transmitting the virus to cats, which often roam freely and can then pass the virus onto humans. This warning comes from a group of six researchers based in Mexico and Germany.

The researchers, led by Aurea Mariana Salgado Cardoso from the Institute of Epidemiological Diagnosis and Reference (Indre) in Mexico, note that the growing population of the Yucatan Peninsula has led to increased human activity in the jungle. This has resulted in the loss of 266,613 hectares of forest over the past 20 years, which have been converted into residential, tourist, or agricultural areas.

This expansion into the jungle, at an average rate of 362 hectares per year, makes it easier for animals to move into new areas. The introduction of potential hosts and pathogens significantly contributes to the emergence of infectious diseases.

Between 2003 and 2022, there were 489 recorded cases of rabies in Yucatan, according to Indre and the Regional Information System for Rabies Epidemiological Surveillance (Sirvera). These cases included a variety of animals such as cattle, goats, coatis, deer, dogs, horses, sheep, skunks, vampire bats, and other wild mammals.

During the same period, nine cases of rabid cats were detected in Yucatan, with four in Merida, the state capital; four in Muna, in the South, and one in Cuncunul, in the East. The researchers note that Merida and Muna are urban areas with large populations, while Cuncunul is a rural community with around 1714 residents.

The researchers also found that human activities have led to changes in the types of rabies detected in these nine Yucatan cats. The first case of a cat with confirmed rabies in Yucatan in 2003 was infected with the RVV1 variant, which is related to dogs. Between 2017 and 2021, seven cats were infected with the atypical RVV variant, which is of canine origin and associated with wildlife. The most recent case, in 2021, was a cat infected with the RVV3 variant of rabies, which originates from the vampire bat.

Cats pose a threat to wild species such as bats, birds, and rodents, in both wild and human-modified areas. The researchers found that cats, whether owned or stray, primarily preyed on bats in rural and less populated urban areas, while cats in densely populated areas caught fewer bats.

The researchers also provided information on the circumstances of the rabid cats. Four kittens, aged 2-4 months, were rescued on the Muna-San José Tipceh road in 2017. The cases in Merida involved a cat in 2003 (no further data available), a three-month-old kitten found in a house in 2018, a male kitten of the same age rescued and adopted in two different houses in 2019, and a one-year and two-months old male cat also rescued and adopted in two residences in 2021. The most recent case was a female cat who tested positive for rabies.