that they were in fact infected with a human influenza b like virus that had circulated in humans in 1995 and had undergone an antigenic shift since adaptation to its new seal host. tuberculosis red deer, wild boar: in areas of intensive game management that included big game fencing, supplementary feeding locations, and grazing livestock, cases of tuberculosis lesions in wild red deer and wild boars appeared. some boars and deer shared the same strains of tuberculosis which were similar to those found in livestock and humans suggesting a possible sapronotic or sapro-zoonotic contamination of shared water sources, supplemental feed, direct contact with humans or livestock, or their excretions. e. coli dogs, horses: evidence of infection by human e. coli strains in several dogs and horses across europe was found, thus implicating the possibility of zoonotic inter-special transmission of multiresistant strains from humans to companion animals and vice versa. tuberculosis dog: a yorkshire terrier was admitted into a veterinary clinic with a chronic cough, poor weight retention, and vomiting being reported for months where it was revealed that the owner had recovered from tuberculosis, however the dog initially tested negative for tuberculosis in 2 different molecular assays and was discharged. 8 days later the dog was euthanized because of a urethral obstruction. a necroscopy was performed where liver and tracheobronchial lymph node samples in fact tested positive for the exact same strain of tuberculosis the owner had previously. this is a very clear case of reverse zoonosis. influenza a virus subtype h1n1 ferrets: ferrets are often used in human clinical studies thus the potential for human influenza to infect them was previously confirmed. however confirmation of natural transference of a human h1n1 strain from the 2009 outbreak in household pet ferrets further implicates human to animal transference. covid-19 amidst the 2020 global pandemic of covid-19, susceptibility of cats, ferrets, dogs, chickens, pigs, and ducks to the sars-cov-2 coronavirus was examined and it was found that it can be replicated in cats and ferrets with lethal results. cats: the virus can be transmitted in the air between cats. viral rna was detected in feces within 3–5 days of infection and pathological studies detected viral rna in the soft palate, tonsils, and trachea. kittens acquired massive lesions in the lungs, nasal and tracheal mucosa epitheliums. surveillance for sars-cov-2 in cats should be considered as an adjunct to elimination of covid-19 in humans. ferrets: ferrets were inoculated with viral strains from the environment of the huanan seafood market in wuhan, china as well as human isolates from wuhan. it was found that with both isolates, that the virus can replicate in the upper respiratory tract of ferrets for up to 8 days without causing disease or death and viral rna was detected in rectal swabs. pathological studies performed after 13 days of infection revealed mild peribronchitis in the lungs, severe lymphoplasmacytic perivasculitis and vasculitis amongst other ailments with antibody production against sars-cov-2 detected in all ferrets. the fact that sars-cov-2 replicates efficiently in the upper respiratory tract of ferrets makes them a candidate animal model for evaluating antiviral drugs or vaccine candidates against covid-19. dogs: of the beagle dogs tested, viral rna was detected in fecal matter and 50% of the beagles that were inoculated seroconverted after 14 days while the other 50% remained seronegative demonstrating a low susceptibility to sars-cov-2 in dogs. chicken, duck, pig: there was no evidence of susceptibility in chickens, ducks, or pigs with all viral rna swabs returning negative results and seronegative after 14 days post inoculation. influenza a virus subtype h1n1 nelson, m. i., & vincent, a. l. (2015). reverse zoonosis of influenza to swine: new perspectives on the human-animal interface. trends in microbiology, 23(3), 142–153. https://doi.org/10.1016/j.tim.2014.12.002 turkeys: a norwegian turkey breeder's flock exhibited a decrease in egg production with no other clinical signs after a farm hand reported having h1n1. a study revealed that the turkeys also had h1n1 and were seropositive to its antigens. maternally derived h1n1 antibodies were detected in egg yolks and further genetic analyses revealed an identical h1n1 strain in the turkeys as the farm worker who likely infected the turkeys during artificial insemination. pigs: human to pig h1n1 transmission was reported in canada, korea, and eventually came to include every continent save antarctica during the 2009 outbreak. it has also been known to spread during seasonal epidemics in france between humans and pigs. methicillin-resistant staphylococcus aureus horses: 11 equine patients admitted into a veterinary hospital for various reasons from different farms over the span of approximately one year exhibited mrsa infections later. considering that mrsa isolates are extremely rare in horses, it was suggested that the mrsa outbreak was due to nosocomial infection derived from a human during the horse's stay at the hospital. cows, turkeys, pigs: a case of reverse zoonosis was proposed to explain how a particular human methicillin sensitive streptococcus aureus strain was found in livestock (pigs, turkeys, cows) with not only a loss of human virulence genes (which could decrease zoonotic potential for human colonization) but also the addition of methicillin resistance and a tetracycline (which will increase occurrence of mrsa infections). the concern here being that excessive antibiotic usage in livestock productions exacerbate the creation of novel antibiotic resistant zoonotic pathogens. tuberculosis elephants: in 1996, the hawthorne circus corporation reported 4 of their elephants and 11 of their keepers harboring m. tuberculosis infections. unfortunately, these elephants had been sub-leased out to different circus acts and zoological gardens all over america. this spurred a nation-wide epidemic, but because tuberculosis isn't a disease that's typically transmitted from animals to humans, it was suggested that the epidemic was because of transference from a human handler to a captive elephant. coronavirus alpacas: a 2007 outbreak of alpaca coronavirus because of the intermingling happening at a national alpaca exhibition led to a comparison between human and alpaca coronaviruses in an attempt to deduce the source of the outbreak. it was found that the alpaca coronavirus is most evolutionarily similar to a human coronavirus strain that was isolated in the 1960s suggesting that an alpaca coronavirus could have very well been circulating for decades causing respiratory illness in herds undetected for lack of diagnostic capabilities. it also suggests a human to alpaca mode of transmission. measles non-human primates: in 1996, a measles outbreak occurred in a sanctuary in 94 non-human primates. although the source of the outbreak was never determined, serum and urine testing proved that the virus was definitely associated with recent human cases of measles in the u.s. helicobacter pylori marsupials: the stripe-face dunnart is an australian marsupial that has faced multiple outbreaks of helicobacter pylori in captivity. stomach sampling from the marsupial revealed that the h. pylori strain responsible for the outbreaks aligned 100% with a strain originating from the human intestinal tract. thus, it can be assumed that the outbreak was caused by the handlers. coronaviruses chimpanzees: the transmission of the human coronavirus hcov-oc43 to wild chimpanzees (pan troglodytes verus) living in the taï national park, côte d'ivoire was reported in 2016 to 2017. these chimpanzees were accustomed to human presence that had been studying these particular communities since the 1980s the hcov-oc43, belonging to the species betacoronavirus 1 (betacov1), normally causes episodes of common cold in humans (this excludes sars and mers), but has also been detected in ungulates, carnivores, and lagomorphs. therefore, it is completely plausible that researchers or poachers could have inadvertently spread the virus to the chimpanzees thus revealing yet another interface in coronavirus host switching. rhinovirus c chimpanzees: though previously considered a uniquely human pathogen, human rhinovirus c was determined to be the cause of a 2013 outbreak of respiratory infections in chimpanzees in uganda. examination of chimpanzees from all over africa found that they show a universal homozygosity for the 3 cdhr3-y529 allele (cadherin related family member) which is a receptor that drastically increases susceptibility to rhinovirus c infection and asthma in humans. if respiratory viruses of human origin are capable of maintaining circulation in non-human primates, this would prove to be harmful should the infection spillback into human communities. tuberculosis elephants: a necroscopy of a free-ranging african elephant (loxodonta africana) in kruger national park in south africa found significant lung damage due to a human strain of m. tuberculosis. elephants explore their environment with their trunks therefore it was very likely that aerosolized pathogens from domestic waste, contaminated water from a human community upstream, human excrement, or contaminated food from tourists was the source of the infection. pneumoviruses chimpanzees: in uganda, reports of respiratory viruses of human origination infected two chimpanzee (pan troglodytes schweinfurthii) communities in the same forest. it was later discovered to be caused by a human metapneumovirus (also known as mpv, pneumoviridae, metapneumovirus) and a human respirovirus 3 (also known as hrv3, paramyxoviridae, respirovirus, or formerly known as parainfluenza virus 3). reverse zoonosis in gorillas gorillas: conservational areas subject to ecotourism in uganda, rwanda, and the democratic republic of the congo, free-ranging gorillas have become increasingly accustomed to the presence of humans whether that be in the form of ranger guides, tourists, trackers, veterinarians, poachers, or researchers. iodamoeba buetschlii, giardia lamblia, chilomastix sp., endolimax nana, entamoeba coli, and entamoeba histolytica have been found in the feces of gorillas and promiscuous defecations left behind by humans encroaching on the habitat. additionally, increased numbers of cryptosporidium sp. and capillaria infections were found in gorillas that maintained more frequent contact with humans than those that did not. together these findings suggest the occurrence of reverse zoonoses.