The association of erythromycin ethylsuccinate with acute colitis in horses in Sweden

In Sweden there are several reports of mares developing acute colitis while their foals were being treated orally for Rhodococcus equi pneumonia with the combination of erythromycin and rifampicin. In this study 6 adult horses were given low oral dosages of these antibiotics, singly or in combination. Within 3 days post administration of erythromycin, in one case in combination with rifampicin, 2 horses developed severe colitis (one fatal). Clostridium difficile was isolated from one of the horses, whereas no specific pathogens were isolated from the other. Both horses had typical changes in blood parameters seen in acute colitis. Clostridium difficile was also isolated from the faeces of a third horse given an even lower dosage of erythromycin in combination with rifampicin. This horse developed very mild clinical symptoms and recovered spontaneously. In the fourth horse given erythromycin only, very high numbers of Clostridium perfringens were isolated. The horses given rifampicin only did not develop any clinical symptoms and there were no major changes in their faecal flora. In conclusion, it has been demonstrated that low dosages of erythromycin ethylsuccinate can induce severe colitis in horses associated with major changes of the intestinal microflora. Clostridium difficile has been demonstrated as a potential aetiological agent in antibiotic-induced acute colitis.     

Clostridium difficile: prevalence in horses and environment,and antimicrobial susceptibility

REASONS FOR PERFORMING STUDY: Clostridium difficile has been associated with acute colitis in mature horses. OBJECTIVES: To survey C. difficile colonisation of the alimentary tract with age, occurrence of diarrhoea and history of antibiotic therapy; and to study the occurrence and survival of C. difficile in the environment and antimicrobial susceptibility of isolated strains. METHODS: A total of 777 horses of different breeds, age and sex were studied. Further, 598 soil samples and 434 indoor surface samples were examined. Antimicrobial susceptibility of 52 strains was investigated by Etest for 10 antibiotics. RESULTS: In horses that developed acute colitis during antibiotic treatment, 18 of 43 (42%) were positive to C. difficile culture and 12 of these (28%) were positive in the cytotoxin B test. Furthermore, C. difficile was isolated from a small number of diarrhoeic mature horses (4 of 72 [6%]) with no history of antibiotic treatment, but not from 273 healthy mature horses examined or 65 horses with colic. An interesting new finding was that, in normal healthy foals age < 14 days, C. difficile was isolated from 1/3 of foals (16 of 56 [29%]). All older foals (170) except one were negative. Seven of 16 (44%) nondiarrhoeic foals treated with erythromycin or gentamicin in combination with rifampicin were also excretors of C. difficile. On studfarms, 14 of 132 (11%) outdoor soil samples were positive for C. difficile in culture, whereas only 2 of 220 (1%) soil samples from farms with mature horses were positive for C. difficile (P = < 0.001). By PCR, it was demonstrated that strains from the environment and healthy foals can serve as a potential reservoir of toxigenic C. difficile. The experimental study conducted here found that C. difficile survived in nature and indoors for at least 4 years in inoculated equine faeces. The susceptibility of 52 strains was investigated for 10 antibiotics and all were susceptible to metronidazole (MIC < or = 4 mg/l) and vancomycin (MIC < or = 2 mg/l). CONCLUSIONS: C. difficile is associated with acute colitis in mature horses, following antibiotic treatment. Furthermore, C. difficile was isolated from 1 in 3 normal healthy foals age < 14 days. POTENTIAL RELEVANCE: Strains from healthy foals and the environment can serve as a potential reservoir of toxigenic C. difficile.     

A prospective study of the roles of clostridium difficile and enterotoxigenic Clostridium perfringens in equine diarrhoea

Faecal samples from adult horses and from foals with diarrhoea or with normal faeces were evaluated for the presence of Clostridium difficile, C. difficile toxins, C. perfringens enterotoxin (CPE) and C. perfringens spore counts. Clostridium difficile was isolated from 7/55 horses (12.7%) and 11/31 foals (35.5%) with colitis, but from 1/255 normal adults (0.4%) and 0/47 normal foals (P<0.001). Clostridium difficile toxins A and/or B were detected in 12/55 diarrhoeic adults (21.8%) and 5/30 diarrhoeic foals (16.7%) but in only 1/83 adults (1.2%) and 0/21 foals with normal faeces (P<0.001 and P<0.05, respectively). Clostridium perfringens enterotoxin was detected in 9/47 diarrhoeic adults (19%) and 8/28 diarrhoeic foals (28.6%), but was not detected in 47 adult horses (P<0.002) or 4 foals (P = 0.22) with normal faeces. The positive predictive value of isolation of C. perfringens with respect to the presence of CPE was only 60% in adult horses and 64% in foals. There was no association between total C. perfringens spore count and CPE in the faeces. The overall mortality rate from colitis was 22% for adult horses and 18% for foals. Clostridium difficile toxin-positive adult horses with colitis were less likely to survive than C. difficile-negative horses with colitis (P = 0.03). This study provides further evidence that C. difficile and enterotoxigenic C. perfringens are associated with equine enterocolitis.     

Clostridium perfringens type C and Clostridium difficile co-infection in foals

Clostridium perfringens type C is one of the most important agents of enteric disease in newborn foals. Clostridium difficile is now recognized as an important cause of enterocolitis in horses of all ages. While infections by C. perfringens type C or C. difficile are frequently seen, we are not aware of any report describing combined infection by these two microorganisms in foals. We present here five cases of foal enterocolitis associated with C. difficile and C. perfringens type C infection. Five foals between one and seven days of age were submitted for necropsy examination to the California Animal Health and Food Safety Laboratory. The five animals had a clinical history of acute hemorrhagic diarrhea followed by death and none had received antimicrobials or been hospitalized. Postmortem examination revealed hemorrhagic and necrotizing entero-typhlo-colitis. Histologically, the mucosa of the small intestine and colon presented diffuse necrosis and hemorrhage and it was often covered by a pseudomembrane. Thrombosis was observed in submucosal and/or mucosal vessels. Immunohistochemistry of intestinal sections of all foals showed that many large bacilli in the sections were C. perfringens. C. perfringens beta toxin was detected by ELISA in intestinal content of all animals and C. difficile toxin A/B was detected in intestinal content of three animals. C. perfringens (identified as type C by PCR) was isolated from the intestinal content of three foals. C. difficile (typed as A(+)/B(+) by PCR) was isolated from the intestinal content in 3 out of the 5 cases. This report suggests a possible synergism of C. perfringens type C and C. difficile in foal enterocolitis. Because none of the foals had received antibiotic therapy, the predisposing factor, if any, for the C. difficile infection remains undetermined; it is possible that the C. perfringens infection acted as a predisposing factor for C. difficile and/or vice versa. This report also stresses the need to perform a complete diagnostic workup in all cases of foal digestive disease.     

Real-time PCR and typing of Clostridium difficile isolates colonizing mare-foal pairs

Clostridium difficile infection can occur in the dams of sick foals, but it is unknown if mares and foals share the same isolates. In this study, C. difficile isolates from fecal samples of 11 mares paired with 11 foals were genotyped by arbitrarily primed PCR; two mares and three foals in five mare-foal pairs had diarrhea. Fecal immunoassays were utilized to detect C. difficile common antigen and toxin A. Quantitative real-time PCR (qPCR) systems were developed to detect genes for toxins A and B, as well as for binary toxin B. Sequences of all toxins were present in all isolates, although only one horse was positive for toxin A on fecal immunoassay. Identical strains of C. difficile were present in 4/11 (36.4%) mare-foal pairs. Mare-foal pairs can harbor C. difficile subclinically and are potential reservoirs for colonization of each other.     

Clostridium difficile associated with acute colitis in mature horses treated with antibiotics

Clostridium (C.) difficile, or its cytoxin, was demonstrated in faecal samples from 10 of 25 (40%) mature horses investigated with acute colitis treated primarily with antibiotics for disorders other than diarrhoea. C. difficile was not found in faecal samples from 140 horses without signs of enteric disorders, from 21 nondiarrhoeic horses treated with antibiotics, nor from 22 horses with colitis untreated with antibiotics. Except for C. difficile neither Salmonella nor any other investigated intestinal pathogen was isolated in any of the diarrhoeic horses. The findings strongly support some earlier reports that C. difficile is associated with acute colitis in mature horses treated with antibiotics. Of the 10 horses, 4 proved positive for C. difficile both in culture and in the cytotoxin test, 4 in culture only and 2 only in the cytotoxin test. Eight of 10 horses positive for C. difficile were or had recently been hospitalised, indicating that C. difficile may be a nosocomial infection in horses. All horses positive for C. difficile were treated with beta-lactam antibiotics.     

Clostridium difficile diarrhea: infection control in horses.

C difficile has emerged as an important cause of diarrheic disease in horses. C difficile diarrhea is usually diagnosed in mature horses, mostly when they are treated with antimicrobials and hospitalized. It is important for clinicians at veterinary hospitals to have knowledge about the organism and the infection. To prevent C difficile diarrhea, judicious use of antimicrobials is important, as is minimizing different stress factors at the animal hospital or clinic. Infected horses must be isolated. Routine examination for C difficile and toxin A or B is recommended in horses with antibiotic-associated diarrhea. When treating foals for R equi pneumonia, it is important to avoid accidental ingestion of erythromycin by the dams. To reduce the number of environmental spores, thorough cleaning and surface disinfection of the animal hospital and clinic are important. Routine handwashing should be performed by all staff.     

Experimental Clostridium difficile enterocolitis in foals

Despite empirical clinical association of infection with Clostridium difficile with colitis in horses, a causal link has not been confirmed. The objective of this study was to develop a model of C. difficile-associated diarrhea in foals with normal transfer of passive immunity. Nine 1-day-old pony foals were inoculated intragastrically with spores or vegetative cells of C. difficile. Five foals were challenged with spores, with 2 receiving 10(5) colony-forming units (CFUs) and concurrently 3 receiving 10(7) CFUs once daily for 3 days. Clindamycin was administered orally to disrupt gastrointestinal flora. A further 4 foals were challenged by orogastric administration of 10(10) CFUs of vegetative cells once daily for 3 days or until diarrhea developed. This group did not receive clindamycin. Spore and vegetative cell preparations were negative for toxins of C. difficile and common enteropathogens. Clinical signs varied from mild abdominal discomfort and pasty feces to colic and watery diarrhea in 8 of 9 foals. Four of 5 foals challenged with spores developed mild diarrhea, whereas all foals challenged with vegetative cells developed moderate to severe diarrhea. C. difficile was isolated from feces of all foals between 24 and 72 hours after inoculation and toxins A or B or both were detected in the feces of all foals by an enzyme-linked immunosorbent assay. We concluded that spores and vegetative cells of C. difficile are capable of colonizing the gastrointestinal tract, producing toxins, and inducing clinical signs similar to those encountered in naturally occurring cases. This study fulfilled Koch's postulates for C. difficile-associated diarrhea in foals and provides a model for consistent reproduction of the disease for future studies.     

Antimicrobial susceptibilities of canine Clostridium difficile and Clostridium perfringens isolates to commonly utilized antimicrobial drugs

Clostridium difficile and Clostridium perfringens are anaerobic, Gram-positive bacilli that are common causes of enteritis and enterotoxemias in both domestic animals and humans. Both organisms have been associated with acute and chronic large and small bowel diarrhea, and acute hemorrhagic diarrheal syndrome in the dog. The objective of this study was to determine the in vitro antimicrobial susceptibilities of canine C. difficile and C. perfringens isolates in an effort to optimize antimicrobial therapy for dogs with clostridial-associated diarrhea. The minimum inhibitory concentrations (MIC) of antibiotics recommended for treating C. difficile (metronidazole, vancomycin) and C. perfringens-associated diarrhea in the dog (ampicillin, erythromycin, metronidazole, tetracycline, tylosin) were determined for 70 canine fecal C. difficile isolates and 131 C. perfringens isolates. All C. difficile isolates tested had an MIC of or=256 microg/ml for both erythromycin and tylosin. A third C. perfringens isolate had an MIC of 32 microg/ml for metronidazole. Based on the results of this study, ampicillin, erythromycin, metronidazole, and tylosin appear to be effective antibiotics for the treatment of C. perfringens-associated diarrhea, although resistant strains do exist. However, because there is limited information regarding breakpoints for veterinary anaerobes, and because intestinal concentrations are not known, in vitro results should be interpreted with caution.     

Clostridium difficile infection in humans and animals, differences and similarities

Clostridium difficile is well known as the most common cause of nosocomial infections in human patients. In recent years a change in epidemiology towards an increase in incidence and severity of disease, not only inside the hospital, but also in the community, is reported. C. difficile is increasingly recognized in veterinary medicine as well and is now considered the most important cause of neonatal diarrhea in swine in North America. Research on the presence of C. difficile in production and companion animals revealed a huge overlap with strains implicated in human C. difficile infection (CDI). This has lead to the concern that interspecies transmission of this bacterium occurs. In this review C. difficile infections in humans and animals are compared. The pathogenesis, clinical signs, diagnosis and prevalence of CDI are described and similarities and differences of CDI between humans and animals are discussed.     

Characterization of Clostridium difficile isolates from foals with diarrhea: 28 cases (1993-1997)

OBJECTIVE: To determine molecular characteristics of Clostridium difficile isolates from foals with diarrhea and identify clinical abnormalities in affected foals. DESIGN: Retrospective study. ANIMALS: 28 foals with C difficile-associated diarrhea. PROCEDURE: Toxigenicity, molecular fingerprinting, and antibiotic susceptibility patterns were determined. Information on signalment, clinical findings, results of clinicopathologic testing, whether antimicrobials had been administered prior to development of diarrhea, and outcome was obtained from the medical records. RESULTS: Twenty-three (82%) foals survived. Toxin A and B gene sequences were detected in isolates from 24 of 27 foals, whereas the toxin B gene alone was detected in the isolate from 1 foal. Results of an ELISA for toxin A were positive for fecal samples from only 8 of 20 (40%) foals. Ten of 23 (43%) isolates were resistant to metronidazole. Molecular fingerprinting revealed marked heterogeneity among isolates, except for the metronidazole-resistant isolates. Sixteen foals had tachypnea. Hematologic abnormalities were indicative of inflammation. Common serum biochemical abnormalities included metabolic acidosis, hyponatremia, hypocalcemia, azotemia, hypoproteinemia, hyperglycemia, and high enzyme activities. Passive transfer of maternal antibodies was adequate in all 12 foals evaluated. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that a large percentage of C difficile isolates from foals with diarrhea will have the toxin A and B gene sequences. Because of the possibility that isolates will be resistant to metronidazole, susceptibility testing is warranted. Clostridium difficile isolates from foals may have a substantial amount of molecular heterogeneity. Clinical and hematologic findings in affected foals are similar to those for foals with diarrhea caused by other pathogens.     

Acute diarrhea in horses of the Potomac River area: examination for clostridial toxins

Fecal specimens from horses in Montgomery County, Md, and in Fairfax and Loudoun counties, Va, were examined for Clostridium perfringens type A enterotoxin and for C difficile cytotoxin (92 and 108 specimens, respectively). The toxins were found in feces from horses that had experienced an acute diarrhea syndrome and from clinically normal horses. The toxins did not appear to be primary determinants of the diarrhea syndrome, although they may have contributed to the spectrum of clinical entities observed.     

Infectious Agents Detected in the Feces of Diarrheic Foals: A Retrospective Study of 233 Cases (2003–2008)

Background: Diarrhea is common in foals but there are no studies investigating the relative prevalence of common infectious agents in a population of hospitalized diarrheic foals.
Objectives: To determine the frequency of detection of infectious agents in a population of hospitalized foals with diarrhea and to determine if detection of specific pathogens is associated with age, outcome, or clinicopathologic data.
Animals: Two hundred and thirty-three foals ≤ 10 months of age with diarrhea examined at a referral institution.
Methods: Retrospective case series. Each foal was examined for Salmonella spp., viruses, Clostridium difficile toxins, Clostridium perfringens culture, C. perfringens enterotoxin, Cryptosporidium spp., and metazoan parasites in feces collected at admission or at the onset of diarrhea.
Results: At least 1 infectious agent was detected in 122 foals (55%). Rotavirus was most frequently detected (20%) followed by C. perfringens (18%), Salmonella spp. (12%), and C. difficile (5%). Foals < 1 month of age were significantly more likely to be positive for C. perfringens (odds ratio [OR] = 15, 95% confidence interval [CI] = 3.5–66) or to have negative fecal diagnostic results (OR = 3.0, 95% CI = 1.7–5.2) than older foals. Foals > 1 month of age were significantly more likely to have Salmonella spp. (OR = 2.6, 95% CI = 1.2–6.0), rotavirus (OR = 13.3, 95% CI = 5.3–33), and parasites (OR = 23, 95% CI = 3.1–185) detected compared with younger foals. Overall 191 of the 223 foals (87%) survived. The type of infectious agent identified in the feces or bacteremia was not significantly associated with survival.
Conclusions and Clinical Importance: In the population studied, foals with diarrhea had a good prognosis regardless of which infectious agent was identified in the feces.     

Efficacy of Hyperimmunized Plasma in the Treatment of Horses with Acute Colitis

Colitis in the adult horse is a life-threatening clinical condition that can be caused by any of several enteric pathogens. This study was conducted to determine whether treating horses with plasma obtained from donors that were hyperimmunized against the common equine diarrheal pathogens Clostridium difficile, Clostridium perfringens, and Salmonella sp shortens the duration of diarrhea in acute colitis. To evaluate the efficacy of plasma treatment, 42 horses with acute onset of diarrhea were studied. Horses were enrolled if they were of age >1 year, duration of diarrhea at presentation was <72 hours, and they had not received equine plasma within the last 3 months. In addition, the serum cortisol concentrations of horses with acute diarrhea were studied.Horses were randomized to receive hyperimmunized plasma, control plasma (collected from nonimmunized horses), or no plasma therapy. Clinical parameters and fecal consistency were observed until resolution, discharge, or death, and complete blood counts (CBCs) and biochemical profiles were collected throughout the study. A total of 38 horses completed the study. The mean duration of diarrhea was 40.7 ± 9.8 (mean ± SEM) hours, 119.2 ± 56.1 hours, and 72.0 ± 24.5 hours for the hyperimmunized plasma, normal plasma (NP), and control groups, respectively. Using survival analysis techniques, this difference did not achieve statistical significance (P = .374). Serum cortisol was found to be increased in all horses at presentation and to decrease with time in all treatment groups. There was no difference in cortisol concentrations between the three treatment groups studied (P = .237).     

Insulin sensitivity and glucose dynamics during pre-weaning foal development and in response to maternal diet composition

Nutritional management of animals during pregnancy can affect glucose and insulin dynamics in the resulting offspring through influences on fetal development. Additionally, high starch feeding in mature horses is associated with reduced insulin sensitivity and an increased risk for diseases such as obesity and laminitis. However, no study has yet evaluated the effect of feeding a high starch diet to pregnant mares on glucose and insulin dynamics in their offspring. Twenty late-gestation mares maintained on pasture were provided two-thirds of digestible energy requirements from isocaloric, isonitrogenous low starch (LS, n = 10) or high starch (HS, n = 10) feed. Their foals were assessed with an insulin-modified frequently sampled intravenous glucose tolerance test at 5, 40, 80, and 160 d of age. Baseline glucose concentrations, insulin sensitivity, and insulin-independent glucose clearance in 5-d foals were all greater than values observed in mature horses and declined towards mature values as foals reached 160 d of age. Baseline glucose concentrations were all within normal range, but higher in foals born from HS mares through 80 d of age. Insulin sensitivity was not different between dietary groups until a trend for lower insulin sensitivity in HS foals emerged at 160 d of age. These data are the first to characterize decreasing insulin sensitivity and glucose tolerance in Thoroughbred foals from 5 to 160 d of age. This study also presents the first data examining glucose and insulin dynamics in developing foals in response to maternal high starch diet.     

The emergence of Clostridium difficile as a pathogen of food animals

Clostridium difficile causes pseudomembranous colitis in humans, usually after disruption of the bowel flora by antibiotic therapy. Factors mediating the frank disease include the dose and toxigenicity of the colonizing strain, its ability to adhere to colonic epithelium, the concurrent presence of organisms that affect multiplication and toxin production or activity, and the susceptibility of the host. Toxins A (an enterotoxin) and B (a cytotoxin) play the major role in pathogenesis and the detection of toxins in gut contents is the gold standard for diagnosis. Disease in horses takes the form of often-fatal foal hemorrhagic enteritis. Nosocomial, antibiotic-associated, disease is increasingly common in adult horses. Enteric clinical signs are reported in ostriches, companion animals and recently calves. Clostridium difficile colitis is now a common diagnosis in neonatal pigs in the USA and elsewhere. Clinical features include onset at 1-5 days of age, sometimes with dyspnea, mild abdominal distension and scrotal edema, and commonly with yellow, pasty diarrhea. There is mesocolonic edema grossly, with microscopic diffuse colitis, mucosal edema, crypt distension, epithelial necrosis and superficial mucosal erosion. Neutrophil infiltration of the lamina propria is common, and fibrin and numerous rod-shaped bacteria are observed on the surface. About two-thirds of litters and one-third of piglets will be affected (based upon positive toxin tests), although this appears to vary with the season. The case fatality rate is probably low if considering only direct effects of C. difficile infection. The significance of toxin-positive non-diarrheic pigs and the nature of the interaction of toxins A and B with enterocytes are unknown. Given the widespread occurrence of the disease, there is substantial effort to develop immunoprophylactic products.     

Clostridium piliforme infection (Tyzzer disease) in horses: retrospective study of 25 cases and literature review

Tyzzer disease (TD) is caused by Clostridium piliforme, a gram-negative and obligate intracellular bacterium. The disease occurs in multiple species. A triad of lesions, namely colitis, hepatitis, and myocarditis, is described in cases of TD in some species, such as rats and mice. We carried out a retrospective analysis of 25 equine cases with a diagnosis of TD; 24 of 25 cases occurred in foals <45 d old; the remaining foal was 90 d old. There were 12 males and 12 females; no sex information was available for one foal. The affected breeds were Quarter Horse, Thoroughbred, Arabian, Paint, and Hanoverian. Most of the cases (19 of 25) occurred in the spring. There were 9 cases of sudden death; the remaining animals had diarrhea, fever, distended abdomen, depression, weakness, non-responsiveness, and/or recumbency. Gross findings included icterus, hepatomegaly with acinar pattern, serosal hemorrhages, pulmonary edema, and/or fluid content in small and large intestine. Microscopically, all foals had severe, multifocal, necrotizing hepatitis. Necrotizing lymphohistiocytic colitis was observed in 10 of 25 foals, and multifocal necrotizing myocarditis was found in 8 of 25. Gram-negative, Steiner-positive, intracytoplasmic filamentous bacteria were observed in hepatocytes, enterocytes, and myocardiocytes, respectively. PCR detected C. piliforme DNA in the liver (24 of 24), colon (20 of 24), and heart (5 of 25). Our results indicate that necrotic hepatitis is the hallmark of TD in horses; the so-called triad of lesions is not a consistent characteristic of the disease in this species.     

Molecular characterization of Clostridium difficile isolates from horses in an intensive care unit and association of disease severity with strain type

OBJECTIVE: To determine molecular characteristics, antimicrobial susceptibility, and toxigenicity of Clostridium difficile isolates from horses in an intensive care unit and evaluate associations among severity of clinical disease with specific strains of C difficile. DESIGN: Prospective study. ANIMALS: 130 horses. PROCEDURES: Feces were collected from horses admitted for acute gastrointestinal tract disease with loose feces and submitted for microbial culture and immunoassay for toxin production. Polymerase chain reaction assays were performed on isolates for toxins A and B genes and strain identification. RESULTS: Isolates were grouped into 3 strains (A, B, and C) on the basis of molecular banding patterns. Toxins A and B gene sequences were detected in 93%, 95%, and 73% of isolates of strains A, B, and C, respectively. Results of fecal immunoassays for toxin A were positive in 40%, 63%, and 16% of horses with strains A, B, and C, respectively. Isolates in strain B were resistant to metronidazole. Horses infected with strain B were 10 times as likely to have been treated with metronidazole prior to the onset of diarrhea as horses infected with other strains. Duration from onset of diarrhea to discharge (among survivors) was longer, systemic inflammatory response syndromes were more pronounced, and mortality rate was higher in horses infected with strain B than those infected with strains A and C combined. CONCLUSIONS AND CLINICAL RELEVANCE: Horses may be infected with a number of heterogeneous isolates of C difficile. Results indicated that toxigenicity and antimicrobial susceptibility of isolates vary and that metronidazole-resistant strains may be associated with severe disease.     

Epidemiologic survey of diarrhea in foals

Epidemiologic and etiologic data about diarrhea in foals were collected under a planned prospective recording and monitoring study. The survey and monitoring procedures included a survey to obtain an overview of current horse management practices on participating farms, a daily health record survey to obtain information on mares and their foals, and collection of feces from 19 of 144 diarrheic foals and 10 age-matched nondiarrheic foals for electron microscopy, ELISA for rotavirus, and bacteriologic culture. Coronavirus was detected in the feces of diarrheic as well as clinically normal foals. Rotavirus was detected in the feces of diarrheic foals only. With regard to agents found in the feces, there was no significant (P less than 0.05) difference between diarrheic and nondiarrheic foals. Half of the 297 foals on which data were available developed diarrhea. Most foals that developed diarrhea lacked other clinical manifestations of disease. Basic cleanliness at foaling was associated with a lower percentage of foals developing diarrhea. Prophylactic use of antibiotics and vitamins in newborn foals was associated with a higher percentage of foals developing diarrhea. A higher percentage of foals born to visiting mares developed diarrhea, compared with foals born to resident mares.     

The effect of the sedative and analgesic detomidine for laryngoscopy of adult horses and foals]

Detomidine was used in this field trial effectively as a sedative and analgesic for laryngoscopic examinations in a total of 193 foals and 806 mature horses (Hanoverians). Detomidine was given either i.v. in foals 3 to 11 months old (20 micrograms/kg) and in mature horses (15 micrograms/kg), or i.m. in foals below 6 months of age (35 micrograms/kg). After i.v. administration, laryngoscopy was tolerated in more than 90% of all animals without additional use of a twitch, while in foals treated i.m. more than 70% required a twitch in order to enable this procedure. The effectiveness of detomidine was influenced by dose, route of administration, the time interval between treatment and examination and the degree of excitement before treatment, but not by sex. Profound bradycardia was evident in all treated animals, but arrhythmias were seen only in animals older than 4 months and were more pronounced in horses with a lower resting heart rate. These cardiovascular responses never endangered any of the treated animals. A transient dyspnea was seen in 13 foals (6.7%) and 10 horses (1.2%). Other side effects were rare. The foaling rate of 297 mares treated at any time during the first 8 months of pregnancy was 66.7%. A comparison with 5499 untreated, contemporary controls revealed a foaling rate of 61.0%. Hence treatments had no adverse effects on pregnancies.