the piglets are infected in utero. nasal, fecal and vaginal swabs of infected sows were performed and pure cultures of a. equuli were only found in the vaginal swabs, supporting the hypothesis of in utero infection. navel swabs and blood tests were performed on affected piglets and no a. equuli was cultured and bacteremia was not found. the pathogenicity causing the variation in clinical manifestations between cases of swine affected with a. equuli is not well understood. the virulence factors of a. equuli in swine is also not well known. rabbits there has been one case that found a rabbit presenting for necropsy, had a secondary infection caused by a. equuli. the rabbit was diagnosed with acute hepatitis characteristic of tyzzer's disease caused by clostridium piliforme. however, samples of the lungs and liver of the rabbit also resulted in the culture of a. equuli subspecies haemolyticus. a. equuli was determined to be a secondary opportunistic invader in this rabbit. clinical signs horses acute signs: moderate to severe abdominal pain (colic), inappetence, intestinal stasis, lethargy. chronic signs: weight loss less frequently a. equuli has also been known to cause respiratory tract disease, abortion, haemorrhagic diatheses, pericarditis, periorchitis, enteritis, and peritonitis. sleepy foal syndrome: the acute form of sleepy foal syndrome presents as sepsis that can lead to death. acutely infected foals appear dull, can have pneumonia and are neutropenic. however, in some cases a chronic form of the disease can manifest in the kidneys, lungs, and joints resulting in lesions to the affected areas. necropsies of horses infected with a. equuli showed consistent diffuse, bilateral, multifocal renal infarcts affecting the renal cortices. fibrinous exudate and pulmonary edema was also a common finding. swine acute signs in sows: most commonly lethargy, inappetence, sudden death. less commonly causes recumbency, hyperesthesia, pneumonia, bronchitis, surface wound infections, metritis, and septicemia. acute signs in piglets: lethargy, +/- pyrexia, severe arthritis (causing them to be non-weight bearing on that limb), encephalitis (although only neurological signs were lateral recumbency), septicemia and sudden death. chronic signs of piglets and sows: poor doing and weight loss leading to culling or euthanasia sow necropsies: sows most commonly had dehydration, subcutaneous hemorrhage, embolic infarcts consisting of neutrophils and basophilic bacilli in the renal cortex. embolic infarcts were also found in liver, lungs spleen, adrenal gland. sows were concluded to have died of renal infarcts. gilt necropsy: a gilt was found to have liquefactive necrosis in the epicardium of both auricles of the heart, valvular endocarditis of both mitral and tricuspid valves and thrombus of the right atrial wall. she had recently aborted her pregnancy and within the amniotic sacs of the aborted fetuses, a brown serous fluid was found. the gilt was concluded to have died of a. equuli causing valvular endocarditis and metritis with secondary septicemia. piglet necropsies (6 hours to 4 days old belonging to infected sows): piglets had petechial hemorrhage and multiple bacterial emboli in the renal cortex +/- multifocal purulent nephritis. piglets were also found to have severe diffuse fibrinopurulent arthritis in one or more joints. some piglets have additionally had a mild purulent encephalitis and perivasculitis of the vessels in the brain. prevention and treatment horses a. equuli causing sleepy foal syndrome in neonatal horses is most often attributed to the mother, as a. equuli is part of the normal microflora of the mare which makes it difficult to prevent exposure of the foal to a. equuli. in a majority of reported cases, sleepy foal syndrome is more than likely a direct result of failure of passive transfer thus, it is important that neonatal foals receive colostrum to reduce the incidence of the disease caused by a. equuli. reducing environmental contamination when the foal is born has also shown to be effective at reducing the incidence of disease. in adult horses, there has been a reported case of infection caused by a. equuli associated with gastrointestinal ulceration possibly due to the use of phenylbutazone for extended periods of time. ulceration of the gi mucosa can allow a. equuli to set up an opportunistic infection. limiting the duration or dose of phenylbutazone could reduce the chance of ulceration and thus an infection. preventative treatments can also include minimizing the risk of infection with other parasites or pathogens that could weaken the immune system or cause physical damage that allows a. equuli to set up an infection. some studies have found that a. equuli infections have been established after exposure with strongylus vulgaris as the migrating larvae can transport a. equuli to various parts of the body resulting in infection. overall, ensuring the health of the horse is maintained has shown to be the best strategy to reduce infection with a. equuli. treatment and supportive care of a horses infected with a. equuli has been shown to be very effective when detected early, resulting in low incidence of death associated with infection. one study involving 51 horses with peritonitis associated with a. equuli, found treatment with procaine penicillin or procaine penicillin and gentamicin sulphate to be effective. however, antimicrobial sensitivity testing of 14 cultures showed 1 culture to be resistant to penicillin, 1 resistant to trimethoprim-sulphadimidine and 1 resistant to a combination of penicillin and trimethoprim-sulphadimidine. thus the study recommended the treatment with procaine penicillin and gentamicin sulphate in cases of antimicrobial resistance. in neonatal foals with sleepy foal syndrome, treatment failure resulting in fatal outcome has been recorded because of the severity of the condition and an inability of the neonate to successfully mount an immune response against the pathogen due to failure of passive transfer. in other cases, treatment of sleepy foal syndrome included antibiotic treatment with amoxicillin-clavulanic acid and amikacin sulfate along with fluid therapy. swine during the outbreak at the swine farm in canada, both preventative antibiotic therapy in the water and feed of the entire herd and individual therapy of the clinically affected sows was administered. susceptibility testing showed that a. equuli was sensitive to ampicillin, tetracycline, trimethoprim, ceftiofur, neomycin and spectinomycin. clinically affected sows were determined by failure to rise when stimulated and temperature, and were additionally treated with antibiotics and anti-inflammatories. some of the clinically affected sows who survived the initial infection were euthanized or culled due to wasting and poor-doing. sow mortality ranged from an average of 8 deaths per day at the beginning of the outbreak, to 2 deaths/day by day 50 of the infection. prevention of a. equuli spread in swine operations with herd outbreak from the infected to the non-infected sows or newly introduced gilts was mitigated by the development of a herd-specific killed vaccine. zoonotic potential a. equuli commonly affects equine hosts. occasionally, a. equuli has been found to cause disease in sows and their newborn piglets. there was one case describing a rabbit who was infected with a. equuli. humans have also been found to have infections caused by a. equuli after being bit by a horse. one case study described a stable hand who had been bitten by a horse 12 hours prior, presenting to the hospital with a red and swollen laceration on the dorsal side of his hand. a. equuli-like species was cultured from the wound and was determined to cause the infection along with a. lignieresii. additionally, there has been one case of a 13-year-old boy who developed meningitis and sepsis from a. equuli. the boy had visited a farm 3 days prior but denied coming into direct contact with horses or pigs. furthermore, a blood sample from a 53 year old butcher with septicemia was found to contain a. equuli after the individual had lacerated his left thumb. prior to the discovery, a. equuli had never been recorded in the blood of a human with septicemia. susceptibility and resistance susceptibility testing performed found that a. equuli was sensitive to ampicillin, tetracycline, trimethorprin, ceftiofur, neomycin, cefotaxime, ceftazidime, imipenem, meropenem, ciprofloxacin, levofloxacin, piperacillin-tazobactam, tigecycline and spectinomycin. however, after conducting susceptibility testing, one study found a. equuli resistance to penicillin, ampicillin, streptomycin, neomycin, chloramphenicol, methicillin, and nalidixic acid. the study also found susceptibility of a. equuli to gentamicin, tetracycline, nitrofurantoin, polymyxin b, sulphonamides, trimethoprim with sulphonamides, carbenicillin, cephalotin, and amoxycillin with clavulanic acid. the study did note it had differing results in susceptibility tests than other studies had reported, which could be a result of regional or strain differences or differences in the methods of the susceptibility testing between studies. additional reports have found a. equuli resistance to oxacillin and trimethoprim-sulphadimidine along with developed resistance to tetracycline after one month of use in sows.