Vetnews | Maart 2026 20 « BACK TO CONTENTS SUSPECTED GLYPHOSATE POISONING IN A DOG Abstract Glyphosate is a widely used pesticide that has been associated with poisoning in both humans and animals. Its toxicity remains a topic of controversy, particularly regarding its carcinogenic potential. This study aimed to investigate a suspected case of glyphosate poisoning in a dog, providing a detailed account of the case history, clinical evolution, laboratory findings, and genotoxic assessment. A seven-month-old dog was referred to the Veterinary Hospital, presenting with mental confusion and ataxia. The pet guardian reported altered consciousness and incoordination twelve days after Roundup® was applied to the farm’s grass. A complete blood count revealed normocytic normochromic anaemia, a packed cell volume of 20%, thrombocytopenia (50,000/ µL), and severe leukocytosis (447,200/µL), with 95% of the white blood cells consisting of blasts of unidentified origin and 5% segmented neutrophils. Myelogram analysis showed a moderately cellular bone marrow sample with a predominance of primitive cells of undetermined origin (>95%), suggesting a diagnosis of leukaemia. To further investigate the potential link between leukaemia and glyphosate exposure, whole blood was collected in a heparinised tube for a comet assay. The test indicated moderate DNA damage. Chemotherapy was recommended; however, treatment was not pursued for personal reasons, and the patient died five days after the consultation. A necropsy was not authorised. This report contributes to the understanding of glyphosate poisoning and its potential health consequences, particularly its association with hematologic malignancies in canines. Introduction Glyphosate is the most widely used herbicide in the world, applied in both agricultural and domestic settings. Accidental poisonings have been reported in both animals and humans (DAWSON et al., 2010; KARTHIKRAJ et al., 2019; KUNAPAREDDY; KALISETTY, 2021). Previous studies indicate that dogs and cats exposed to glyphosatebased products exhibit gastrointestinal and respiratory effects, primarily due to the surfactants used in these formulations (BATES; EDWARDS, 2013). Additionally, clinical signs such as vomiting, diarrhoea, and lethargy have been observed. In humans, evidence suggests that glyphosate has potential carcinogenic and immunogenic effects (PEILLEX; PELLETIER, 2020; RANA et al., 2023); however, these findings have yet to be confirmed through large-scale cohort studies (ANDREOTTI et al., 2018). In other mammalian species, such as pigs, glyphosate exposure has been shown to impact the number of galaninergic neurons in the intestine and alter the expression of galanin receptors in the small intestinal wall (PALUS et al., 2024). In rodents, exposure has been linked to impairments in spatial orientation, navigation, learning, and memory (CHÁVEZ-REYES et al., 2024; 2025). The debate surrounding glyphosate toxicity has intensified over the years. In 2015, the International Agency for Research on Cancer (IARC) classified glyphosate as “probably carcinogenic to humans.” However, a joint evaluation by the WHO and FAO in 2016 concluded that glyphosate was not carcinogenic in rats but could not rule out carcinogenic potential in mice at very high doses. In the same year, a systematic review found insufficient evidence to support an association between Roundup® exposure and lymphohematopoietic cancers (CHANG; DELZELL, 2016). It is crucial to consider several factors when assessing glyphosate poisoning. Some studies on the compound have been met with controversy due to methodological limitations, lack of scientific rigour, and conflicts of interest, particularly regarding funding sources. Nonetheless, animal exposure to glyphosate poses a potential health risk. Thus, this study aims to report a clinical case of suspected glyphosate poisoning in a dog in Brazil. To investigate this case, we conducted a comprehensive evaluation, including physical, neurological, and genotoxic examinations. Article Ana Flávia Machado Botelho, Rayanne Henrique Santana Da Silva, Sara Sueli Ferreira De Almeida , Cilho Gabriel Rodrigues Leopoldino, Ana Gabriela Rodrigues Leopoldino, Pedro Henrique De Miranda Passos, Luiza Gabriella Ferreira De Paula, Daniela Melo E Silva, Danieli Brolo Martins, Marcelino Benvindo-Souza
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