# Toxic and Environmental Effects of Neonicotinoid Based Insecticides
## 2 Neonicotinoids and Its Effects after Human Exposure  
While there is limited information regarding human exposure to neonicotinoids, cases of neonicotinoid poisoning are rising due to the use of these insecticides [11; 12]. From 2000 to 2012, poison centers in Texas, USA received 1142 neonicotinoid exposure cases, where most products (77%) contained imidacloprid. The most common exposure routes were ingestion, dermal, and ocular. Typical adverse reactions included ocular, dermal, and oral irritation; nausea; vomiting; erythema; and red eye [11]. [PERSON] et al. reported the clinical results and toxico-kinetics of the neonicotinoid insecticide imidacloprid; it causes acute self-poisoning in humans [13]. Demographic and clinical data were obtained in patients with imidacloprid exposure in three hospitals in Sri Lanka [14]. [PERSON] et al. [14] reported that the imidacloprid poisoning rates are underestimated. They reported a case of a 62-year-old Saudi male cultivator who was admitted to the emergency department with a history of fever, disorientation, lower abdominal pain, vomiting, etc. They reported that this may be the first reported case of leukocytochastic vasculitis due to skin contact with imidacloprid and inhalation exposure. [PERSON] et al. [12] reported a retrospective analysis involving cases of neonicotinoid ingestion in Korean emergency departments from March 2002 to February 2010. Of the 24 patients analyzed, the most common signs of neonicotinoid toxicity were gastrointestinal symptoms, including nausea, vomiting, and abdominal pain, as well as respiratory symptoms, cardiovascular symptoms, metabolic imbalance, and renal dysfunction. Moderate toxicity was reported in  
Figure 1: An overview of neonicotinoids and their components. Figure 2: Neonicotinoids eliminate sap-feeding insects and negatively affect pollinators. 83.3% of the patients, and 16.7% sustained fatal conditions with an overall mortality rate of 4.2% [12]. Since imidacloprid, thiacloprid, thiamethoxam, dinotefuran, clothianidin, and acetamiprid fall under the class of neonicotinoids, the details of each one are presented in the below sections. _Imidacloprid:_ Of the many neonicotinoids, imidacloprid is the most prominent. Imidacloprid is a colorless crystal and is generally acknowledged as a useful pesticide for pest management, especially for insects with piercing and sap-feeding mouthparts [15]. Imidacloprid is used to protect crops, turf, and decorative plants from pests, such as termites and fleas, by acting on their nicotinic receptors, which are transmembrane allosteric proteins that play a critical physiological role in the body by enabling the transduction of chemo electrical signals throughout the nervous system [16]. Through calcium ion imbalance, mitochondrial dysfunction, oxidative stress, and effects on DNA, imidacloprid causes failure to the nervous system that ultimately leads to death. Applications of imidacloprid include leaf spraying as well as soil and seed treatments, which can impact non-target organisms such as pollinators or other insects that are beneficial to farming, which can be financially unfavorable. For example, the individual immunity of bees can be affected by imidacloprid, which may diminish their defenses, making them vulnerable to parasites and pathogens [15]. Recently, there has been a growing concern about imidacloprid's impact on the ecosystem and human health. Such concerns have been investigated, and it was uncovered that imidacloprid is toxic to humans and has acute toxic effects including severe respiratory failure and loss of consciousness [15]. [PERSON] et al. [15] further reported that imidacloprid is toxic to mammals, including human beings, and it can kill bees, bats, earthworms, fish, and other non-target organisms; thus, the development of cost-effective and eco-friendly methods, such as biological oxidation utilizing microbial consortium with degrading enzymes, is necessary. Shadnia and Moghaddam [17] reported a fatal case of imidacloprid insecticide poisoning.