Editing Fancy rat (section)

== Health ==
{{See also|Brown rat#Diseases|l1=Diseases in the brown rat}}
[[File:Brown hooded rat with a large tumor.jpg|thumb|Fancy rats of both sexes commonly develop [[mammary tumor]]s as they age. These are usually [[Benign tumor|benign]], but multiple tumors can persist even after removal.<ref name=merck-neoplasia>{{cite web|url=http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/171562.htm|title=Merck Veterinary Manual – Neoplasia|access-date=7 January 2009}}</ref>]]
Human-raised ''[[R. norvegicus]]'' are more prone to specific health risks and diseases than their wild counterparts, but they are also far less likely to succumb to certain illnesses that are prevalent in the wild. The major considerations for susceptibility include exposure, living conditions, and diet.{{Citation needed|date=March 2024}}

Rats that live their entire lives indoors usually are able to avoid disease-causing bacteria such as [[Salmonellosis|''Salmonella'']] and ''[[Pseudomonas aeruginosa]]''; the latter is absent in treated water. They may also more easily avoid [[Vector (epidemiology)|vectors]] like cockroaches, beetles, and fleas which are essential for the spread of [[endemic typhus]] and intestinal parasites like the [[Hymenolepiasis|rat tapeworm]].<ref name="merck-skin">{{cite web|url=http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/171546.htm|title=Merck Veterinary Manual – Skin Diseases|access-date=9 January 2009}}</ref><ref name="merck-gastro">{{cite web|url=http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/171544.htm|title=Merck Veterinary Manual – Gastrointestinal Diseases|access-date=9 January 2009}}</ref> Additionally, pet or laboratory rats enjoy the intrinsic benefits of having a consistent and well-balanced diet, along with access to medical care.

[[Porphyrin]]<ref>{{Cite web|url=http://ratguide.com/health/eyes/porphyrin_secretions_red_tears.php|title=Porphyrin Secretions / Red Tears – Rat Guide}}</ref> is a browny-red substance that fancy rats can develop around the eyes and nose. It may appear like dried blood, but is a [[mucus]]-like substance that is released at times of stress or if the rat has a [[respiratory infection]]. It can also be caused by temporary irritation in the eye, such as the rat accidentally scratching its eye while grooming.<ref>{{Cite web|url=http://ratta.co.uk/care/|title=Pet Rats – Rat Care – Ronnie and Derek|last=Watts|first=David|website=Pet Rats – Ronnie and Derek|language=en-GB|access-date=2019-04-09}}</ref>

Mites also pose a health risk. [[Mites of domestic animals|Mites]] are microscopic bloodsucking [[parasite]]s that can irritate the skin of fancy rats, and if they have a preexisting health condition, it can cause them to die from their bodies' inability to handle two problems at once.{{Citation needed|date=March 2024}}

While living indoors decreases the risk of contracting certain diseases, living in close quarters with other rats, lack of proper protection from environmental factors (e.g. temperature, humidity), an unhealthy diet, and the stresses inherently associated with living in an unnatural habitat can all adversely affect a rat's health to make them more prone to specific conditions.<ref name="merck-skin" /><ref name="merck-manage">{{cite web|url=http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/171543.htm|title=Merck Veterinary Manual – Management|quote=Ambient temperatures &gt;85°F (29.4°C), high humidity levels (&gt;80%), poor ventilation, and overcrowding predispose rodents to heat exhaustion.|access-date=7 January 2009}}</ref><ref>{{cite web|url=http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/171548.htm|title=Merck Veterinary Manual – Reproductive Diseases|access-date=9 January 2009}}</ref> Specifically, [[Tyzzer's disease]], protozoic infections (e.g. ''Giardia muris''), and pseudotuberculosis are usually seen in stressed or young rats.<ref name="merck-gastro" /><ref name="merck-resp">{{cite web|url=http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/171545.htm|title=Merck Veterinary Manual – Respiratory Diseases|access-date=9 January 2009}}</ref> Additionally, pet rats are exposed to ''[[Streptococcus pneumoniae]]'', a [[zoonotic]] disease caught from humans, not the same bacteria associated with [[pneumonia]]. A human-associated fungus, ''[[Pneumocystis jirovecii]]'' (also found in almost all domesticated animals), is usually asymptomatic in the rat, unless the rat's [[immune system]] is compromised by illness. If this occurs, the infection can develop into [[pneumonia]].<ref name="merck-resp" />

Several diseases, like Rat Coronavirus Infection (RCI), [[Sendai virus]], and Murine Respiratory Mycoplasmosis (MRM, ''[[Mycoplasma|Mycoplasma pulmonis]]''), are prevalent simply because their highly contagious natures work in tandem with the way rats are kept in laboratories, [[pet store]]s, and by breeders.<ref name="merck-gastro" /><ref name="merck-resp" /> MRM is far less likely to occur in laboratory rats than in those kept as pets.<ref name="merck-resp" />

Pet rats can also develop [[Pituitary adenoma|pituitary tumors]] if fed high-calorie diets,<ref name="merck-neoplasia" /> and [[ringtail (disease)|ringtail]] if placed in areas with low humidity or high temperatures.<ref name="ratguide-health">{{cite web|url=http://ratguide.com/health/integumentary_skin/ringtail.php|title=Health Guide- Ringtail|access-date=24 April 2009}}</ref> ''[[Staphylococcus]]'' spp. are a mostly benign group of bacteria that commonly reside on the top of the skin, but cuts and scratches from [[social animal|social]] and hierarchical fighting can open up the pathways for them to cause [[ulcerative dermatitis]].<ref name="merck-skin" />

There is some evidence that spayed female rats ("does") are less likely to develop mammary and [[pituitary tumor]]s than intact females.<ref>{{Cite web|url=http://www.ratfanclub.org/spay.html|title=the Rat Report|website=www.ratfanclub.org|access-date=2016-03-30}}</ref> Research into prevention of common diseases and health issues in rats is ongoing. Dietary changes are among the main suggestions for improved health and longevity in fancy rats, including feeding rat-friendly superfoods <ref>{{Cite web|url=http://www.ratcentral.com/superfoods-for-rats/|title=11 Superfoods To Add To Your Rats Diet – RatCentral|website=RatCentral|language=en-US|access-date=2016-03-30|date=2016-03-29 |last1=Cole |first1=Jane }}</ref> in moderation to reduce the risk of [[cancer]]s, [[heart disease]], and stroke.

=== Risks to owners ===
Keeping rats as pets can come with the stigma that rats supposedly transmit dangerous diseases to their owners. Usually, rats bred as pets are tested and treated for diseases and parasites. One fear is that all rats carry [[plague (disease)|plague]], when in fact ''R. norvegicus'' is not among the list of species considered a threat.<ref name="JAVMA" /> In 2004, an outbreak of [[salmonella]] in the United States was connected to people who owned pet rats.<ref name="cdc">{{cite web|url=https://www.cdc.gov/mmwr/preview/mmwrhtml/mm5417a3.htm|title=Outbreak of Multidrug-Resistant Salmonella Typhimurium Associated with Rodents Purchased at Retail Pet Stores|date=May 6, 2005|publisher=[[Centers for Disease Control]]|access-date=14 November 2008}}</ref> However, it has been determined that a pet rat's initial exposure to salmonella, along with many other zoonotic rat diseases, typically indicates exposure to wild rodent populations, either from an infestation in the owner's home, or from the pet's contaminated food, water, or bedding.<ref name="merck-general" />

Another risk to rat owners is [[rat-bite fever]]. This is a rare disease among domesticated rats and is most often found in rats from large chain pet stores that breed their stock of rats in masses (usually with the intention of being snake food rather than pets) or from breeders with neglectful rat husbandry. This disease is fairly unnoticeable in the rat, but is characterized by swelling of the bite or scratch site, fever, vomiting, and body aches. It is contracted by the bite or scratch of an infected rat.<ref>{{cite web
| url = https://www.cdc.gov/rat-bite-fever/symptoms/index.html
| title = Signs and Symptoms &#124; Rat-bite Fever (RBF)
| website = www.cdc.gov
| access-date = 2016-02-25
}}</ref> As an early breeder of fancy rats, 19th-century rat catcher [[Jack Black (rat catcher)|Jack Black]] recounted that he nearly died several times after bites.<ref name=Mayhew>{{cite book |title=London Labour and the London Poor, Volume 3 |chapter=Chapter I: The Destroyers of Vermin |last=Mayhew |first=Henry |date=1851 |chapter-url=https://dl.tufts.edu/teiviewer/parent/5x21ts300/chapter/c1s5}}</ref>

In 2017, the [[Centers for Disease Control]] reported an outbreak of [[Seoul virus]] spread by pet rats.<ref>{{Cite web|url=https://www.cdc.gov/hantavirus/outbreaks/seoul-virus/index.html|title=Multi-state Outbreak of Seoul Virus|website=www.cdc.gov|language=en-us|access-date=2017-05-27}}</ref>