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Congenital anomalies of the superior vena cava are rare and often coexist with other cardiac abnormalities. In this report, we present a case of absent bilateral superior vena cava with no associated cardiac anomaly. Blood from the arms, head, and upper torso returned to the right atrium through the azygos vein and the inferior vena cava, mimicking chronic superior vena cava obstruction.

Peripheral auditory frequency tuning in the ensiferan insect Cyphoderris monstrosa (Orthoptera: Haglidae) was examined by comparing tympanal vibrations and primary auditory receptor responses. In this species there is a mis-match between the frequency of maximal auditory sensitivity and the frequency content of the species' acoustic signals. The mis-match is not a function of the mechanical properties of the tympanum, but is evident at the level of primary receptors. There are two classes of primary receptors: low-tuned and broadly tuned. Differences in the absolute sensitivity of the two receptor types at the male song frequency would allow the auditory system to discriminate intraspecific signals from sounds containing lower frequencies. Comparisons of tympanal and receptor tuning indicated that the sensitivity of the broadly tuned receptors did not differ from that of the tympanum, while low-tuned receptors had significantly narrower frequency tuning. The results suggest that the limited specialization for the encoding of intraspecific signals in the auditory system of C. monstrosa is a primitive rather than a degenerate condition. The limited specialization of C. monstrosa may reflect the evolutionary origin of communication-related hearing from a generalized precursor through the addition of peripheral adaptations (tympana, additional receptors) to enhance frequency sensitivity and discrimination.

Hypersensitivity pneumonitis (HP) in workers exposed to metal removal fluids (MRFs) is increasing. This study supports the hypothesis that aerosolized mycobacteria colonizing the MRFs likely cause the disease. Three case studies of HP outbreaks among metal workers showed potentially high exposures to a rare and newly proposed Mycobacterium species. Retrospective review of samples submitted to our laboratory showed an association between presence of mycobacteria and HP.

Objective: The pharmacokinetics of flosequinan were studied in a group of 18 patients with chronic cardiac failure., Results: After a single dose of 100 mg, Cmax of the parent compound (2.52 mg.l-1) was recorded at 1.4 h, and of the sulphone metabolite flosequinoxan at 21.7 h. The plasma elimination half lives of the parent compound (6.4 h) and of the metabolite (54.3 h) were prolonged compared to previous studies in normal volunteers. After repeated dose administration for 36 days, the kinetics of the parent compound and metabolite remained essentially unchanged with an expected significant accumulation of metabolite (Cmax 8.4 vs 3.21 mg.l-1). No adverse effects were observed., Conclusion: It is possible that altered drug kinetics in patients with heart failure, probably related to altered hepatic blood flow, could contribute to drug toxicity.

Two hundred and nine patients with moderate to severe chronic heart failure, all of whom remained symptomatic despite at least 80 mg of frusemide daily, were randomized to 12 months treatment with flosequinan or captopril. The patients were stratified into two groups, a treadmill group and a corridor walk test group, depending upon their exercise capability. Sixty-five out of 102 patients randomized to flosequinan and 43 out of 107 randomized to captopril (p < 0.001) did not complete the study. There was no difference between the groups in mortality: 19 patients died while taking flosequinan and 15 while taking captopril. Both drugs had similar effects on treadmill exercise tolerance; the mean increase at week 52 was 117 seconds in the flosequinan group and 156 seconds (p = 0.57) for the captopril group. For those patients stratified to the corridor walk test only, there was also very little difference in the improvement at 52 weeks; the mean increase for patients randomized to flosequinan was 61 meters and captopril was 75 meters (p = 0.65). However, when the walk tests from all patients are examined, captopril produced a significant improvement compared with flosequinan at week 52 (p = 0.015). Flosequinan has similar long-term efficacy to captopril but is associated with a higher incidence of adverse events.

Insurers are investing in information technology to provide the data that are essential to the management of their delivery systems. A Blue Cross and Blue Shield medical director explains some practical applications, including outcomes evaluation, provider selection and practice pattern comparisons.

Objective: To examine the concentration of circulating tumour necrosis factor alpha (TNF alpha) in patients with severe congestive heart failure (New York Heart Association class IV) during one year and to correlate changes in this cytokine with changes in plasma noradrenaline, plasma renin activity, and weight., Design: A prospective study of the role of TNF alpha in severe chronic heart failure. Blood samples were collected at intervals of three months., Setting: Medical research centre of a teaching hospital., Patients: 16 patients with chronic stable severe heart failure., Interventions: Vasodilator treatment with captopril or flosequinan., Main Outcome Measures: Changes in TNF alpha and the correlation with changes in plasma noradrenaline, plasma renin activity, and weight during optimal medical treatment for one year., Results: The mean concentration of TNF alpha was greater than the upper 95% confidence interval for healthy controls throughout the year of the study but there was considerable between and within patient variation. No correlation was seen between TNF alpha and plasma noradrenaline, plasma renin activity, or weight., Conclusions: The stimulus resulting in enhanced plasma concentrations of TNF alpha in congestive heart failure remains unclear and concentrations at any particular time were not prognostic.

Objective: To follow the change in streptokinase neutralisation titres in a group of patients after treatment with streptokinase for acute myocardial infarction., Design: Venous blood samples suitable for analysis were obtained up to 866 days after treatment with 1.5 million units of streptokinase in 189 patients. The ability of the patient's plasma to inhibit lysis of a thrombin clot by streptokinase was assessed., Setting: A coronary care unit in a district general hospital., Patients: A retrospective review of coronary care records and the district health authority computer showed that 329 patients who had received streptokinase were alive. All were invited for venepuncture and 220 (67%) attended. Satisfactory samples were obtained from 189 patients., Results: Raised titres of antibody sufficient to neutralise a standard dose of 1.5 million units of streptokinase were found in 90% of patients. There was a fall in streptokinase neutralisation titre with increasing time after administration of streptokinase (r = -0.35, P < 0.0001) and though there was considerable variation among the group the neutralisation titre was higher than in the general population in all patients, even those who had received streptokinase at least two years previously., Conclusion: The ability of streptokinase to lyse a thrombin clot was appreciably inhibited in vitro by the plasma from patients who had received 1.5 million units of streptokinase. High streptokinase neutralisation titres persisted for a long time after the use of streptokinase as thrombolytic treatment for acute myocardial infarction. Readministration of streptokinase may not be efficacious for considerably longer than the one year currently advocated. Until the in vivo effects of streptokinase readministration are known a non-antigenic thrombolytic agent should be used instead.

Cardiac hydatid disease is rare, but life threatening. A pedunculated hydatid cyst which mimicked a left atrial myxoma was diagnosed on two-dimensional echocardiography. The degree of cardiac involvement at necropsy was much greater than indicated by either echocardiography or limited cardiac catheterization. The suggestion that only echocardiography be performed before surgery is undertaken may be inappropriate in many cases.

Streptokinase neutralisation titres were measured in a series of 25 patients who received streptokinase for the treatment of acute myocardial infarction. Before treatment, neutralisation titres were low (0.3 X 10(6) neutralisation units or less) in all patients. 3 months after treatment, neutralisation titres in 24 were such that a typical therapeutic dose of 1.5 million units of streptokinase would have been fully neutralised. At 4 1/2-8 1/2 months, 18 of 20 patients had neutralisation titres such that at least 50% of a dose of 1.5 million units of streptokinase would have been neutralised. After 8 months, neutralisation titres ranged from 0.4 to 2.0 million units in 8 patients. A decision to readminister streptokinase within 8 months (and probably up to 1 year) of previous thrombolytic treatment should take account of the neutralising capacity of plasma and the dose should be adjusted accordingly.

Insectivorous bats have influenced the development of antipredator behavior in moths, green lacewings, crickets, and mantids; until recently, such adaptations were unknown in katydids. Foliage-gleaning bats in Panama can use the female-attracting, airborne calling songs of nocturnal katydids to locate prey. They also feed heavily on these insects. Katydid species sympatric with these bats exhibit markedly reduced calling song duty cycles. Males supplement shortened songs with complex, species-specific tremulations that generate vibrations that are inaudible to bats but reach conspecific females through a shared plant substrate. Female katydids do not call audibly but are also preyed on in large numbers, perhaps as a result of moving toward calling males.

We compared two Campylobacter serotyping systems by using 1,405 isolates of Campylobacter collected from human, animal, and environmental sources during epidemiologic investigations and special studies. We found 96.1% of isolates to be typable by the Penner method for heat-stable antigens, which involved the use of an indirect hemagglutination technique, and 92.1% of isolates to be typable by the Lior method for heat-labile antigens, which involved the use of a slide agglutination technique and absorbed antisera. Absorbed antisera were not required for the Penner method, making that method less difficult to implement. The Lior method was simpler to perform and gave more rapid results than did the Penner method. Cultures frequently reacted in multiple antisera with the Penner method, whereas multiple reactions were rare with the Lior method. Thus, results were easier to interpret with the Lior system. Strains of a single serotype in one system were sometimes found to be multiple serotypes in the other system; hence, the two methods have the potential to be complementary. Both systems were comparable in serotyping isolates from human and nonhuman sources and for evaluating the relationship of strains collected during outbreak investigations.

A total of 189 patients with uncomplicated myocardial infarction were selected at random for early or late mobilization and discharge from hospital. Patients were admitted to the study after 48 hours in a coronary care unit if they were free of pain and showed no evidence of heart failure or significant dysrhythmia. Randomization was achieved by monthly cross-over of the three medical wards to which the patients were discharged. One group of patients was mobilized immediately and discharged home after a total of nine days in hospital, and the second group was mobilized on the ninth day and discharged on the 16th day. Out-patient assessment was carried out six weeks after admission. No significant differences were observed between the groups in terms of mortality or morbidity, as reflected by the incidence of recurrent chest pain or myocardial infarction, heart failure, dysrhythmia, or venous thromboembolism detected either clinically or by (125)I-labelled fibrinogen scanning.

We conducted a prospective study of travelers' diarrhea on 73 physicians and 48 family members attending a medical congress in Mexico City, in October, 1974. Fecal and blood specimens were collected before, during and after their visit and examined for enteric bacterial pathogens, viruses and parasites. In 59 (49 per cent) participants travelers' diarrhea developed. Median duration of illness was five days. Onset occurred a median of six days after arrival. An etiologic agent was found in 63 per cent of ill participants. Enterotoxigenic Escherichia coli of different, non-"enteropathogenic" serotypes was the most common cause; other responsible pathogens included salmonellae, invasive Esch. coli., shigellae, Vibrio parahaemolyticus, Giardia lamblia and the human reovirus-like agent. Consumption of salads containing raw vegetables was associated with enterotoxigenic Esch. coli infection (P = 0.014). Travelers' diarrhea in Mexico is a syndrome caused by a variety of pathogens, the most common of which is enterotoxigenic Esch. col.

Recovery of Shigella spp. from fecal specimens transported in buffered glycerol saline and Cary-Blair media held at frozen, refrigerated, or room temperature was compared with recovery by direct plating of fecal specimens. Buffered glycerol saline was the better transport medium for the recovery of Shigella spp. Refrigerated or frozen transport temperatures were superior to room temperature for recovery from either medium.

Only in the last few years has Yersinia enterocolitica been recognized as an etiologic agent. The organism, however, is widespread in both the animate and inanimate environments. It has been isolated and recovered from a variety of sources including fecal material, foodstuffs, and water, but vehicles of disease transmission are not fully delineated or understood. The bacteriology of Y. enterocolitica is reviewed and recommended laboratory methodology is described.

An outbreak of gastroenteritis occurred in March-April 1981, in Wichita, Kansas, and involved more than 250 persons who drank raw milk from a single local dairy. Campylobacter jejuni was recovered from 60 of 116 (52%) persons in households that had one or more ill family members. A cohort study of families that belonged to a food cooperative that purchased raw milk from the implicated dairy showed a significant association between illness and having drunk raw milk. Thirty-nine of 55 (71%) persons who drank raw milk became ill compared with four of 36 (11%) persons who did not drink raw milk (p less than 0.01, t test, accounting for clustering). Peak (convalescent) antibody titers to C. jejuni, determined by indirect immunofluorescence, in 20 raw-milk drinkers showed a geometric mean of 1:27 in contrast to geometric mean titer of 1:6 in 10 well persons from the cohort who did not drink raw milk (p less than 0.002, t test). C. jejuni was recovered from 21 of 34 (66%) raw-milk drinkers, versus none of 26 people who did not drink raw milk (p less than 0.001, Fisher's exact test, one tailed). C. jejuni of the same serotype was isolated from the case-patients and from rectal swabs of cows in the dairy. These findings indicate that raw milk contaminated by Campylobacter was the vehicle for this outbreak.

The Moore swab method was shown to be a practical and sensitive technique for the isolation of Vibrio cholerae from sewage. In each of three instances in which cholera patients lived in homes connected to municipal sewers, V. cholerae was isolated from the community sewage plant intake at the time of the patients illness. Sewer systems became negative within 1 day after patients were treated with tetracycline. Sewer surveillance using the Moore swab also found evidence of infections occurring in areas where surveillance of diarrheal illness failed to detect cholera. Culturing community sewage by the Moore swab method proved to be an economical and effective way of determining areas where V. cholerae infections were occurring.

The test for hippurate hydrolysis is critical for separation of Campylobacter jejuni and C. coli strains. Glycine and benzoic acid are formed when hippurate is hydrolyzed by C. jejuni. The test used in most laboratories is one of several variations of the ninhydrin tube test described by Hwang and Ederer (M. Hwang and G. M. Ederer, J. Clin. Microbiol. 1:114-115, 1975) for detection of glycine. We evaluated three modifications of the Hwang and Ederer method and the gas-liquid chromatographic (GLC) method described by Kodaka et al. (H. Kodaka, G. L. Lombard, and V. R. Dowell, Jr., J. Clin. Microbiol. 16:962-964, 1982) for detecting benzoic acid. Campylobacter strains comprised 22 C. jejuni, 11 C. coli, and 8 C. laridis strains. The species identification of each strain was confirmed by DNA relatedness. All strains of C. jejuni were positive and all strains of C. coli and C. laridis were negative by the GLC method for detecting hippurate hydrolysis, whereas three strains of C. jejuni gave negative or variable results in the tube tests. The GLC method is more sensitive than the tube methods for detecting hippurate hydrolysis and should be used on cultures yielding variable or questionable test results.

Low-dose heparin, dipyridamole (alone and in combination with aspirin), and flurbiprofen were evaluated as potential prophylactic agents against deep venous thrombosis in elderly patients with hip fractures. None of the agents that modify platelet behaviour could reduct the frequency of isotopically diagnosed venous thrombosis. Low-dose heparin reduced the overall frequency of venous thrombosis and its extent as judged by the frequency of bilaterally abnormal scans, but this reduction did not achieve statistical significance.

Cary-Blair medium retains its ability to serve as a transport medium after 19 months of aging at room temperature. This eliminates the necessity for the frequent replacement of the stored supplies of this medium.

A family outbreak of foodborne shigellosis caused by an unusual strain of Shigella is described. The strain was a mannitol-positive variant of Shigella dysenteriae and agglutinated in antiserum prepared against provisional serotype 3341-55.

Out of 305 general practitioners sent a questionnaire asking how they would treat three hypothetical patients with heart attacks 231 (76%) replied. Of these, only 179 were prepared to make an unqualified choice of home or hospital treatment for a middle-aged man with an uncomplicated attack, 70 (39%) saying that they would keep the patient at home. Practitioners qualifying before 1960 were more likely to do this than those qualifying in 1960 or later. If a patient declined hospital treatment 161 (70%) of the practitioners would keep him in bed for a week or less, but the date of the practitioners' qualification significantly affected the time they would advise him to remain off work. Faced with a patient acutely ill after a heart attack, 162 (70%) of the practitioners would arrange his immediate admission to hospital and 51 (22%) would send him to hospital after initial treatment at home. The numbers of partners in the practice, the nature of the premises, and the location of the practice in urban or rural areas affected the practitioners' attitude to the management of severely ill patients but not to the management of patients with uncomplicated attacks.

643 orthopaedic surgeons were sent a questionary asking how they attempted to prevent and diagnose deep venous thrombosis (D.V.T.) in patients with hip fractures. 411 (64%) replied. Of those who replied, 51% offered no prophylaxis, only 3% routinely used oral anticoagulation, and 85% relied on clinical signs in the diagnosis.

The epidemiology of Campylobacter jejuni indicates that waterborne transmission is important; the organism has been isolated from seawater, fresh water, and estuarine sites. Membrane filtration, with and without use of an enrichment broth, has been the most common method for isolating C. jejuni from water. We evaluated two methods for isolating C. jejuni from water: membrane filtration and gauze filtration. The membrane filters evaluated included 0.22- and 0.45-micron-pore Millipore filters (Millipore Corp., Bedford, Mass.), 0.2- and 0.4-micron-pore Nuclepore filters (Nucleopore Corp., Pleasanton, Calif.), and a 0.45-micron-pore Zetapor filters (AMF Cuno, Meridian, Conn.). The gauze filters included both Moore and Spira swabs. Of the membrane filters evaluated, the 0.45-micron-pore Millipore and Zetapor filters were the most sensitive for recovery of C. jejuni from seeded waters. The 0.45-micron-pore Millipore filter placed in Oosterom broth was better for recovery of C. jejuni from seeded stationary surface waters than either the Spira or Moore swab. However, the 0.45-micron-pore Millipore filter placed on a plate or in enrichment broth was equivalent to the Spira gauze swab when used to examine water from Atlanta area streams. C. jejuni organisms were isolated from 9 of 24 surface water samples representing 5 of 12 streams.

A selective medium was developed and used successfully to isolate Legionella pneumophila and Legionella-like organisms from environmental specimens previously positive by animal inoculation methods. This medium consists of charcoal-yeast extract agar to which have been added cephalothin (4 micrograms/ml), colistin (16 micrograms/ml), vancomycin (0.5 microgram/ml), and cycloheximide (80 micrograms/ml). Pretreating of the environmental water samples with an acid buffer (pH 2.2), followed by plating on the selective medium, improved the rate of recovery of both Legionella and Legionella-like organisms relative to that with direct plating on selective media.

Although the cause of venous thrombosis remains obscure, preventive methods have been described. The fact that pulmonary embolism continues to cause a high death toll suggests that there is still a failure to recognize the need for prevention or to employ those prophylactic methods that are known to be effective. While it may be impracticable to offer prophylactic treatment to all patients at risk, an awareness of the important predisposing factors and the application of effective prophylaxis to high risk cases could bring about a reduction in the mortality rate from a disease that at present causes as many unnecessary deaths as motor vehicle accidents.

The results of 125I-fibrinogen leg scanning during life were compared with the findings at a detailed post-mortem dissection of the leg veins in 31 patients with hip fractures who died during the period of isotope scanning or within seven days of the last scan. Thigh scanning on the side of the hip fracture proved valueless, and criteria for the confident isotopic diagnosis of venous thrombosis in the uninjured thigh could not be determined. In the lower leg a difference in uptake of 20% or more that persisted for 24 hours between adjacent positions on one leg or between corresponding positions on the two legs was consistently associated with the presence of venous thrombosis at necropsy.

A questionnaire was completed by 341 senior physicians on their attitudes to four common cardiovascular problems. Their replies showed that uncertainty about the end point for diastolic blood pressure still prevails and that their approach to the management of hypertension of differing severity in men and women of varying ages stems more from personal belief than from the results of clinical trials. Unless patients with atrial fibrillation also had mitral valve disease anticoagulation was not thought to be necessary, thereby making it ethically possible to carry out a trial of anticoagulants in stroke prevention on patients with atrial fibrillation but no valvular disease. The physicians' suggestions for very active management in transient ischaemic attacks extended beyond the evidence available to them, whereas their approach to the use of coronary arteriography closely reflected the results of clinical trials. These findings may indicate that recent cardiovascular trials that have provided definitive results have had more impact than earlier inadequate studies.

In a prospective study of patients admitted to a coronary care unit, the incidence of isotopically diagnosed deep venous thrombosis was found to be related to the severity of illness rather than to the duration of bed rest. In addition, no negative correlation was found between cigarette smoking and deep venous thrombosis.

Thirty-nine cases of Legionnaires' disease in a 16-month period were identified in visitors to and residents of Bloomington, Indiana. Thirty-five patients had spent at least one night at the Indiana Memorial Union in the 2 weeks before becoming ill. Five of 32 sporadic cases nationwide between 1 January and 31 March 1978 were retrospectively shown to be in persons who had recently visited the Union. The risk of acquiring Legionnaires' disease as a Union visitor was at least 17 times greater than that for Bloomington residents 20 years or older. Employees who had worked at the Union 5 years or longer were more likely to be seropositive than workers in other Bloomington hotels. Legionnaires' disease bacterium was isolated from five environmental sites in Bloomington. A cooling tower may have been involved in disease spread, but it was not the only source. Hypochlorite solution was added to cooling tower water as a precautionary measure; however, one case was confirmed in a man with Union exposure 9 days after hypochlorite treatment had begun.

752 orthopaedic and 663 general surgeions were sent a questionnaire asking how they attempted to prevent venous thromboembolism; the survey concerned prophylaxis offered routinely to elderly patients with hip fractures, to patients undergoing elective hip replacement arthroplasty, and to patients undergoing major abdominal and thoracic operations. The response rate was more than 70%. The results suggest that the provision of prophylaxis against venous thromboembolism is inversely related to the frequency with which it occurs--e.g., the proportions of surgeons offering no routine prophylaxis or ambulation and physiotherapy only was 72% for hip fractures, 52% for hip replacement, and 38% for general surgery.

A new selective Campylobacter enrichment broth for the isolation of Campylobacter jejuni has been tested with fecal specimens of human, poultry, and bovine origin. We compared the isolation rate with that from the simultaneous direct plating of a duplicate specimen. Of the 380 duplicate specimens examined comparatively, we obtained a 46.3% increase in isolation of C. jejuni by using the new Campylobacter enrichment broth medium.

Changes in systolic time intervals following the administration of either morphine (0.1 mg/kg) or meptazinol (1 mg/kg) were studied in 12 patients admitted to hospital for intra-abdominal operations. The changes in these indices of cardiac performance were small. However, in 5 of the 6 patients who received morphine, the changes were in a direction suggesting negative inotropism, whereas the changes following meptazinol (6 patients) consistently suggested an improved ventricular performance.

Legionella pneumophila suspended in tap water was exposed to biocides recommended for inhibiting biological growth in cooling towers and evaporative condensers of air-conditioning systems. Chlorine, 2,2-dibromo-3-nitrilopropionamide, and a compound containing didecyldimethylammonium chloride and isopropanol were effective in destroying concentratiois of 10(5) to 10(6) viable cells per ml. Formulations consisting of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one, disodium ethylene bis(thiocarbamate) and sodium dimethyl dithiocarbamate, and a phenolic with pentachlorophenate and sodium salts of other chlorophenols were less effective.

Forty strains of a new Yersinia enterocolitica serotype isolated in the United States from nonhuman primates and humans were characterized as serotype O:13a,13b. Most of the human strains were isolated from a large multistate outbreak of milkborne enteritis. A common antigenic factor between this new serotype and four previously described Y. enterocolitica (O:7,13; O:18; O:44; and O:44,45) led to recharacterization of the latter as serotypes O:7,13a,13b; O:18,13b; O:44,13a; and O:44,13a,45.

Two outbreaks of hemorrhagic colitis, a newly recognized syndrome characterized by bloody diarrhea, severe abdominal pain, and little or no fever, occurred in 1982. No previously recognized pathogens were recovered from stool specimens from persons in either outbreak. However, a rare E. coli serotype, O157:H7, was isolated from 9 of 20 cases and from no controls. It was also recovered from a meat patty from the implicated lot eaten by persons in one outbreak. No recovery of this organism was made from stools collected 7 or more days after onset of illness; whereas 9 of 12 culture-positive stools had been collected within 4 days of onset of illness. The isolate was not invasive or toxigenic by standard tests, and all strains has a unique biotype. Plasmid profile analysis indicates that all outbreak-associated E. coli O157:H7 isolates are closely related. These results suggest that E. coli O157:H7 was the causative agent of illness in the two outbreaks.

Since Yersinia enterocolitica, now classified as a member of the Enterobacteriaceae, was recognized as a distinct species in 1964 it has been isolated with increasing frequency from man and animals (including dogs and pigs) and from some human foods. Y. enterocolitica infections are now seen as a cause for some concern in both human and veterinary medicine. The organism is commonly found in specimens from swine slaughterhouses and has been isolated from samples of market meat, vacuum-packed beef, mussels, oysters, and ice-cream. It has also been found in nonchlorinated well water used for drinking purposes. Infections in man therefore probably have an alimentary origin. Only 23 human infections were recorded in 1966 but the number increased to over 4000 in 1974. However, reported incidence is affected by growing awareness about the role of the organism in human and animal disease and by intensive laboratory analyses. While knowledge about the geographical distribution of Y. enterocolitica is still fragmentary it is clear that infections are very frequent in some parts of the world and probably common but unrecognized in many countries. The most common symptoms of Y. enterocolitica infections in man are fever, abdominal pain, and diarrhoea. In the USA most isolations in human infections were made from blood and mesenteric lymph node samples. The pathogenic mechanism is not known. In one experiment involving a human volunteer subject a dose of 3.5 x 10(9) organisms was required to produce an infection. Only recently has some success been obtained in establishing experimental infections in mice, guinea-pigs, rats, and rabbits. Laboratory cultivation techniques for Y. enterocolitica are described together with a table of minimal tests for characterizing the organism and two biotyping schema. Little is known about methods for controlling this disease, but environmental hygiene and sanitation with regard to food and water should apply.