Pathological and incidental findings in anurans from Ceará, northeastern Brazil

Abstract

Amphibians are among the most threatened animal groups on Earth, with anurans
representing the most prevalent order within this group. Globally, emerging infectious diseases
are linked to the decline of amphibian populations, a phenomenon also observed in northeastern
Brazil. In particular, the state of Ceará boasts a rich and abundant anurofauna, with nearly 5% of its
species considered critically endangered. Despite numerous pathologies observed in local anurans
through research projects, published cases remain scarce. This study aimed to compile pathological
and incidental findings in native anurans from Ceará State, Northeastern Brazil. Data were derived
from necropsies and clinical examinations conducted on 38 specimens across 13 species from 13
sites, spanning from 2010 to 2022. Most lesions (71%, n = 38) indicated inflammatory pathophysiology,
with observations of parasitic infections and agents within lesions, granulomatous or necrotic lesions
with intracytoplasmic inclusions consistent with Mycobacteria and Ranavirus infections, respectively.
Fibrolipomas and hepatocellular carcinoma presented as single solid nodules, the latter associated
with cystic helminth infections. Diffuse hepatic calcinosis suggested a toxic/metabolic etiology.
Bilateral cataract was the most common ocular alteration (60%, n=5), though its etiology remained
undetermined. The presence of infectious diseases was confirmed, and further etiological diagnostics
are necessary. The lack of specific etiological techniques constrained some definitive diagnoses.
These findings place Ceará on the distribution map for significant diseases affecting anurofauna,
underscoring the need for ongoing monitoring.