serious health risks through both the spread of parasites and the presence of noxious ammonia levels. osha, the united states agency regulating air quality standards in work-related environments, has identified an ammonia level of 300 parts per million as life-threatening for humans; in many hoarding cases the atmospheric ammonia level in the housing space approaches this number, requiring the use of protective clothing and breathing apparati during inspections or interventions. in an extreme case, the ammonia level in the hoarder's house was 152 parts per million even after ventilation. the presence of animal waste also prevents sanitary storage and preparation of food, which puts residents at risk of contracting food-related illnesses and parasites. insect and rodent infestation can both follow and worsen hoarding conditions, and can potentially spread to the surrounding environment including to nearby buildings. in one case, an elementary school had to be shut down due to a flea infestation that had spread from a nearby dog hoarder residence. hoarders are frequently found to collect large numbers of inanimate objects in addition to animals, giving rise to clutter as well. hoarded objects can include newspapers, trash, clothing, and food; the clutter inhibits normal movement around the house, hampering household maintenance and sanitary food preparation, heightening the risk of accidents, and contributing to the overall level of squalor. a lack of functioning toilets, sinks, electricity, or proper heating (often due to hoarders not paying bills, though poor maintenance may also be a cause) further exacerbates the problem. fire hazards comprise yet another health issue tied to poor sanitation; the clutter found in many hoarding households prevents workable fire escape plans and serves as possible fuel when located close to heat sources. the risk is amplified when hoarders, due to inoperative heating systems, seek alternate heating methods such as fireplaces, stoves, or kerosene heaters. zoonotic diseases another human health issue caused by animal hoarding is the risk of zoonotic diseases. defined as "human diseases acquired from or transmitted to any other vertebrate animal", zoonotic diseases can often be lethal and in all cases constitute a serious public health concern. examples of well-known zoonotic diseases include bubonic plague, influenza, and rabies. common domesticated animals constitute a large portion of animals carrying zoonoses, and as a result, humans involved in animal hoarding situations are at particular risk of contracting disease. zoonoses that may arise in hoarding situations—through vectors such as dog, cat, or rat bites—include rabies, salmonellosis, catscratch fever, hookworm, and ringworm. one zoonosis of special concern is toxoplasmosis, which can be transmitted to humans through cat feces or badly-prepared meat, and is known to cause severe birth defects or stillbirth in the case of infected pregnant women. the risk of zoonotic diseases is amplified by the possibility of community epidemics. self-neglect and child/elder abuse main article: diogenes syndrome the problems of self-neglect and elder and child abuse are also health problems associated with animal hoarding. self-neglect can be defined as "the inability to provide for oneself the goods or services to meet basic needs", and has been shown to be an "independent risk factor for death". while self-neglect is a condition generally associated with the elderly, animal hoarders of any age can and do experience it. this is demonstrated by the fact that hoarders' lifestyles often match the degenerate sanitary conditions that surround them. child and elder abuse arise when dependents are living with the hoarder. according to one study, dependents lived with hoarders in over half of the cases. as with his or her animals, the hoarder often fails to provide adequate care for dependents both young and old, who suffer from a lack of basic necessities as well as the health problems caused by unsanitary conditions. in one case, two children of a couple hoarding 58 cats and other animals were forced to repeat kindergarten and first grade because of excessive absence due to respiratory infections. self-neglect and neglect of dependents make up a major human health concern of animal hoarding. mental health issues evidence suggests that there is "a strong mental health component" in animal hoarding, though it has not been firmly linked to any specific psychological disorder. models that have been projected to explain animal hoarding include delusional disorder, attachment disorder, obsessive–compulsive disorder, zoophilia, dementia, and addiction. direct evidence for most is lacking, however. delusional disorder animal hoarders display symptoms of delusional disorder in that they have a "belief system out of touch with reality". virtually all hoarders lack insight into the extent of deterioration in their habitations and on the health of their animals, refusing to acknowledge that anything is wrong. furthermore, hoarders may believe they have "a special ability to communicate and/or empathize with animals", rejecting any offers of assistance. delusional disorder is an effective model in that it offers an explanation of hoarders' apparent blindness to the realities of their situations. attachment disorder another model that has been suggested to explain animal hoarding is attachment disorder, which is primarily caused by poor parent-child relationships during childhood. it is characterized by an inability to form "close relationships in adulthood". as a result, those with attachment disorder may turn to animals for companionship. interviews with animal hoarders have revealed that hoarders have often experienced domestic trauma in childhood, which is the basis of the evidence for this model. obsessive–compulsive disorder perhaps the strongest psychological model put forward to explain animal hoarding is obsessive–compulsive disorder (ocd). an overwhelming sense of responsibility for something is characteristic of people with ocd, who then take unrealistic measures to fulfill their perceived duty. animal hoarders often feel a strong sense of responsibility to take care of and protect animals, and their solution—that of acquiring as many animals as they possibly can—is unrealistic. further, the hoarding of inanimate objects, practiced by a majority of animal hoarders, is a fairly common occurrence in people with ocd. these connections between animal hoarding and obsessive–compulsive disorder suggest that ocd may be a useful model in explaining animal hoarding behavior. however, this theory has also been refuted by some; dr. akimitsu yokoyama theorizes that animal hoarding could be explained using asperger syndrome. popular culture and fiction on the animal planet tv series confessions: animal hoarding, friends and family of animal hoarders intervene to offer them support to make a change in the form of psychological help and veterinary care or placement for their pets. in the animated series the simpsons, animal hoarding is represented by the semi-recurring character crazy cat lady eleanor abernathy. she is a mentally ill old woman covered by cats, who is often seen speaking in gibberish and throwing cats at people. in ann bannon's novel journey to a woman, vega's mother and grandfather own an excessive number of cats and could be considered to be animal hoarders. in webtoon lookism, an arc featuring an animal hoarder who nabbed both daniel park and johan song's dogs.