Chapter 4
INTRODUCTION
It is well known that human, animal, and wildlife population are continuously exposed to environmental polluting agents that are harmful to health (Gupta, 1986). Among them are natural and manmade chemicals such as metals, pesticides, organic and inorganic substances, and animal
venoms and toxins, including algal growth and industrial wastes to which domestic animals and wildlife are frequently exposed (Gupta, 2010a,b). In recent years, despite the increasing level of regulation in the use and sale of such products in Asia, their commercialization has intensified. Consequently, many cases of accidental poisoning have occurred. In addition, due to the continuous use of these poisons, accidental or otherwise, these cases have drastically increased all over the world, particularly in developing countries. There is an ongoing need for careful assessment of the risks caused by exposure to these
chemicals. Information on the assessment of toxicity caused by these chemicals mainly comes from human and animal studies (Smith, 2001). However, some supporting information may also be obtained from clinical and in vitro studies. There are no reliable estimates of how many animals suffer from acute poisonings or due to long-term exposure. In general, epidemiology has been
particularly helpful in the evaluation of working environments or other environments where exposure concentrations are relatively high. However, several factors limit the use of epidemiological studies by regulatory agencies (Gupta, 2010a). For example, it is difficult to define the causal elements in epidemiological investigations, particularly when complex exposures are involved. Another imitation
is the frequent movement of animal populations and a large number of animal species available. As such, studies on one population under controlled conditions may be difficult to apply to predict health effects on another animal population. In some developed countries such as the United States, human poison control centers also collect data on animals. In developing countries where there is hard evidence of poisoning including sporadic incidents involving livestock and pets, surveillance is conducted by the veterinary institutions/departments or by the wildlife departments of each country. However, a centralized veterinary poison control/information center does not exist in most countries in Asia. Therefore, in many Asian countries information related to animal poisoning is either unavailable or inadequate and refers only to isolated case reports when it does exist. Occasionally, epidemiological data on animal poisoning gathered by universities, research institutes, government institutions, or independent laboratories has been published in some local journals, which at times
becomes difficult to trace. It is therefore easy to conclude that available data are inadequate to provide sound estimates of the real incidence of poisonings in animal populations and are very likely to be subjected to significant under-reporting (Litchfield, 2005; Gupta, 2016). This chapter focuses on some of the most important poisonous chemicals and plants in Asia and provides an overview
of the poisoning episodes that have occurred in Asian countries.
CONCLUDING REMARKS AND FUTURE
DIRECTIONS
Animals are exposed to potentially toxic agents on a daily basis but the lack of a central reporting agency for animal poisonings makes epidemiological study difficult. With no mandated reporting, many suspected poisoning cases are managed by the attending veterinarian and forgotten. Poisonings are a serious cause of morbidity and mortality in animals, particularly in domestic animals such as cattle (including buffaloes) and dogs; farm animals such as cattle, sheep, goats, poultry; and wild animals and vultures (but rarely cats or other animals). Drug poisonings in animals occur commonly due to off-label use of medicines, wrong dosage, negligence, accidental ingestion, and deliberate poisonings. Accidental or malicious poisonings are due to organophosphorus and carbamate insecticides, fumigants such as aluminum phosphide and zinc phosphide, rodenticides, and rarely due to other agents. Most production animals are kept in some form of confinement, which limits the potential for exposure to toxic agents. However, mistakes in management, such as feed mixing errors or improper ventilation, may result in acute or chronic toxicosis in large number of animals. The most common amongst them is due to nitrateand nitrites, fluoride, Se, Cu (common in sheep) ingestion
of plant, or paddy straw. The other common sources of poisoning include mycotoxins, botulinum, and ionophores (monensin, lasalocid, narasin, and salinomycin). Contamination of feed with antibiotics, pesticides, metals and with other toxins is quite common but their long terms effects are still nknown. For example, in the absence of any systematic survey, the extent to which household kerosene and solid fuels-biomass (wood, agricultural residues, and animal dung) and coal fuels cause long-term damage including morbidity and mortality in companion animals is currently unclear. The scarcity of
adequate epidemiologic and exposure investigations in various Asian countries and the potential for short- and long-term exposure to a vast variety of agents, including household use products and chemicals, suggest a need for agencies to collect epidemiological data on human beings and animals.
for details plz see original article Chapter 4
Gupta PK, (2018) Epidemiology of Animals Poisonings in Asia. In Veterinary Toxicology- Basic and Clinical Principals, Gupta RC (ed) 3nd ed Elsevier, USA pp57-70
Authors: PK Gupta
