Related Experiment Video

Updated: Jan 9, 2026

Integrated Field Lysimetry and Porewater Sampling for Evaluation of Chemical Mobility in Soils and Established Vegetation
10:05

Integrated Field Lysimetry and Porewater Sampling for Evaluation of Chemical Mobility in Soils and Established Vegetation

Published on: July 4, 2014

14.7K

Outbreak of poisoning by sodium hydrogen methylarsonate (MSMA)-an arsenic-based herbicide-in horses in Brazil

Gabriella Faria Pereira1, Maria Clara Hornich Blimbliem1, Anna Laura Previato Rosa Machado1

  • 1School of Veterinary Medicine and Animal Science, Federal University of Uberlândia, Uberlândia, Brazil.

Equine Veterinary Journal
|December 9, 2025
PubMed
Abstract

Insights

Arsenic poisoning in horses is rare but can occur from contaminated pastures. This study documented an outbreak in 31 horses due to an overdose of sodium hydrogen methylarsonate, leading to significant morbidity and mortality.

Area of Science:

  • Veterinary Medicine
  • Toxicology
  • Equine Health

Background:

  • Arsenic compounds in pesticides pose a risk to horses.
  • Arsenic poisoning in horses is infrequently documented.
  • Potential for accidental equine exposure exists.

Purpose of the Study:

  • To investigate an outbreak of arsenic poisoning in horses.
  • To describe epidemiological, clinical, and laboratory findings.
  • To compare outcomes between horses exposed to overdose and recommended doses of sodium hydrogen methylarsonate.

Main Methods:

  • Observational field study involving 31 horses exposed to MSMA-treated pasture.
  • Clinical examinations, haematological, biochemical, and toxicological analyses were performed.
  • Arsenic concentrations were measured in biological and environmental samples.

Main Results:

  • High morbidity (45.2%) and mortality (19.4%) rates observed in the exposed group.
  • Toxicological analysis confirmed elevated arsenic levels.
  • Horses exposed to the recommended dose remained clinically normal.

Conclusions:

  • Arsenic toxicosis impacts equine gastrointestinal, vascular, and renal systems.
  • Diagnosis relies on post-mortem findings, biochemical changes, and arsenic detection.
  • Study limitations included observational design and delayed monitoring.
Keywords:
diarrhoeahorsepetechiaetoxicosis

More Related Videos

Preparation of DMMTAV and DMDTAV Using DMAV for Environmental Applications: Synthesis, Purification, and Confirmation06:23

Preparation of DMMTAV and DMDTAV Using DMAV for Environmental Applications: Synthesis, Purification, and Confirmation

Published on: March 9, 2018

5.9K
Lethality Bioassay Using Artemia salina L.09:09

Lethality Bioassay Using Artemia salina L.

Published on: October 11, 2022

12.0K

Related Concept Videos

Anticholinesterase Agents: Poisoning and Treatment01:26

Anticholinesterase Agents: Poisoning and Treatment

Anticholinesterases, also known as cholinesterase inhibitors, work by blocking the breakdown of acetylcholine, leading to its accumulation in the synaptic cleft. This accumulation indirectly enhances both muscarinic and nicotinic actions. These agents are classified as reversible or irreversible based on their mechanism of action.     
Irreversible agents form a strong bond with the cholinesterase enzyme, making it inactive. The breakdown of the phosphorylated enzyme is...
1.5K
Physical Properties of Amines01:26

Physical Properties of Amines

Amines with low molecular weight are usually gaseous at room temperature, while those with high molecular weight are liquid or solids in nature. Usually, low molecular weight amines have a rotten fish-like smell. Diamines typically have a pungent smell. For instance, cadaverine and putrescine, depicted in Figure 1, are two molecules responsible for decaying tissue.
4.1K
Prevention of Further Absorption of Poison01:14

Prevention of Further Absorption of Poison

In cases of acute poisoning, the primary objective is to prevent further absorption of the toxic substance into the body. Immediate interventions using various decontamination techniques targeting the gastrointestinal (GI) tract can achieve this. Decontamination is crucial to prevent poison from entering the systemic circulation, which involves washing affected areas with water and mild soap and removing contaminated clothing. Once external decontamination is done, attention must be turned to...
1.2K
Local Anesthetics: Adverse Effects01:12

Local Anesthetics: Adverse Effects

While local anesthetics are generally safe and well-tolerated, they can occasionally cause adverse effects that vary in severity. Local anesthetics can induce toxicity at two distinct levels. They can either produce local effects through direct contact with the neural elements or be absorbed into the bloodstream from the injection site, leading to systemic effects.
Once absorbed into the systemic circulation, local anesthetics can affect the organs that depend on the functioning of sodium...
739
Types of Toxins01:36

Types of Toxins

Humans continually engage with an environment rich in potentially harmful chemicals. These are introduced to our bodies through inhalation, ingestion, or skin contact. These chemicals exist in various forms, such as air and environmental pollutants, agricultural chemicals, organic solvents, and heavy metals.
Air pollutants, primarily gases, pose significant threats to respiratory health, leading to conditions like hypoxia, lung cancer, and in extreme cases, death.
Environmental pollutants like...
3.1K
Toxic Reactions: Overview01:26

Toxic Reactions: Overview

When toxic substances penetrate the human body, they disseminate to various tissues, undergoing metabolic changes. This process yields reactive metabolites that may covalently bind with specific target molecules, resulting in toxicity.
Toxicity falls into two primary categories: local and systemic.
Local toxicity appears at the exposure site, such as protein denaturation caused by caustic substances.
In contrast, systemic toxicity requires the toxic agent's absorption and distribution,...
1.8K