Biomedical subjects
Publications and source records attributed to J L Larsen.
In a 32-year-old woman, cerebral angiography showed fibromuscular dysplasia of the left anterior and middle cerebral arteries. She had had epilepsy and subarachnoid hemorrhages with subsequent hemiplegia. Since she also had multiple enchondromas (Ollier disease), this may represent a case of Maffucci syndrome.
Three patients with the combination of long-standing ankylosing spondylitis (AS) and cauda equina syndrome are described and compared with 17 from the literature. The nerve root lesion has been of gradual onset and has since the time of diagnosis either been stationary or progressed slowly. Radicular pain in the feet and legs, and genito-urinary complaints have been the dominant and most disabling symptoms. Typical myelographic findings were expansion of the dural sac and arachnoidal diverticula. There is a highly probable relationship between AS and the neurological syndrome. The pathogenesis is probably related to early arachnoiditis with subsequent loss of meningeal elasticity. Earlier recognition of the root lesion may result in a more effective treatment.
Milk from sows whose progeny developed post weaning E. coli diarrhoea (PWD milk) and from sows which were immunized by intramuscular vaccination using a homologous strain of E. coli (immune milk) were tested in ligated segments of pig intestine. The results showed that PWD milk neutralized the enterotoxigenic, fluid accumulating capacity of the lysate of the disease-causing E. coli pathogen. A similar effect was seen by using immune milk (Table I). Neither PWD milk nor immune milk contained sufficient antibacterial activity to neutralize the fluid accumulating capacity of live cultures of E. coli O149:K91, while such activity was contained in immune serum. It is concluded that milk from sows whose progeny developed PWD contains antibodies capable of neutralizing the enterotoxigenic effects of the homologous E. coli organisms. It is suggested that the presence in milk from these sows of antibody-mediated activity against enteropathogenic E. coli organisms may be instrumental in preventing the disease in the progeny during the suckling period and consequently, when this protective milk supply stops at weaning, the disease may develop in susceptible animals, mainly because their own production of specific E. coli antibodies is insufficient to prevent PWD.
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In the period 1971-73 various extra enteral habitats have been examined for the occurrence of resistant E. coli. Of 172 isolates of E. coli from retail butcher's meat products 9.9% were resistant and 3.5% R+ E. coli. Of 203 isolates of E. coli from bakery products 7.9% were resistant and 3.5% R+ E. coli. Of 52 isolates of E. coli from freshly killed carcases of chickens 40.4% contained weak non-transferable monoresistance against sulphonamides (Table I). Of 92 isolates of E. coli from seawater receiving human sewage 15.2% were resistant and 4.4% R+ E. coli (Table III). All but one samples of sewage and crude sludge contained resistant E. coli of which 11% harboured R factors (Table II). Of 117 Salmonella isolates from human sewage 11.1% were resistant and in 4.2% resistance were transferable (Table VI). Quantitative examinations of untreated and treated sewage did not indicate any selective reduction of resistant E. coli compared to sensitive (Table IV). However, more di- and multiresistant E. coli were found in sewage than in seawater (Fig. 1). The food hygienic implications of resistant E. coli are discussed.
Significant differences have been proved between strains of E. coli isolated from neonatal E. coli diarrhoea (N.C.D.) and post weaning diarrhoea (P.W.D.). The biochemical differences were pronounced in the criteria sucrose, dulcitol, adonitol and urease when comparing the total number of strains from the two syndromes. However, adonitol positive strains were only found among strains of the serogroup O 149:K91(B) of which all the N.C.D.. strains were positive and only 8 of the 86 P.W.D. strains were adonitol fermenters. The dominant fermentation pattern of the N.C.D. strains were sucrose--, dulcitol--, urease--. Contrary the P.W.D. strains were sucrose +, dulcitol +, and 56.6 per cent urease + (Table III). In the possible plasmid determined characters significant differences were found in the ability to produce the K88 antigen and the colicins. The K88 antigen was demonstrated in 97.9 per cent of the N.C.D. strains and 6.2 per cent of the P.W.D. strains whereas 40.6 and 79.6% respectively were colicinogenic. In the serogroup O 149:K91(B) 90.7% of the P.W.D. strains and 47.6% of the N.C.D. strains produced colicins (Table V). The impairment of these features in the pathogenesis of neonatal E. coli diarrhoea, post weaning diarrhoea and the possible causality of the domination of the serogroup O 149:K91(B) is discussed. Furthermore it seems justified to relate the syndrome designation to the serotype of porcine enteropathogenic E. coli strains as it will be difficult to compare strains described from different research workers.
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Faecal swabs from pigs with post weaning E. coli diarrhoea in 43 different herds were bacteriologically examined. A survey of the isolated haemolytic E. coli strains showed that only 1 of the examined strains possessed the K88 antigens and that E. coli strains belonging to serogroup O149:K91 were most frequently isolated. The results suggest that the K88 antigen is of minor significance in the development of post weaning diarrhoea associated with E. coli serotype O149:K91.
In an experimental station for calf feeding the occurrence and distribution of drug resistant E. coli in faeces have been investigated among selected groups of calves. Samples were obatined just after the calves arrived 1--2 weeks old in January--February and at intervals until an age of 7--11 months. Daily from arrival to the age of 8 weeks all calves at the station received antibiotics in their feed. In 1971 it was chlortetracycline and in 1972 zincbacitracin. In addition, from 3.5 percent to 60 percent of all calves were every month given therapeutic doses of antibiotics, mainly penicillin + streptomycin and neomycin. Both years the highest number of treatments were administered in the months of February and March (cf. fig. 1). In each of the years studied, a high prevalence of calves harbouring resistant E. coli (total resistance: greater than 88 percent) and R-+E. coli (1971: 83 percent and 1972: 50 percent) was demonstrated at the first sampling. As the calves grew older a general tendency to exchange the resistant strains with sensitive ones was recognized. The prevalence of calves with R-+ E. coli generally devreased at a faster rate than that of total resistance. A discussion is given of the epidemiological significance of cross infection and of selection pressure of antibiotics for the establishment of a resistant flora in individuals as well as for replacement of this flora with sensitive strains.
The incidence of fatal gastroenteropathies in sucking pigs was studied during a 2-year period in 17 sow herds involving 2,936 litters. The results showed that 2.8 per cent of the liveborn pigs died with gastroenteropathies during the sucking and immediate post weaning period. The incidence was lowest in offspring from second-litter sows (Table I) and the progeny from large litters tended to have the highest incidence (Table II). Fatal gastrointestinal diseases were observed in a total of 17.6 per cent of the examined litters, and the average number of death per affected litter was 1.5 (Tables III and IV). The progeny of sows with post parturient diseases had significantly higher death losses than had the progeny from normal healthy sows (Table V). Climate had no apparent influence on death losses, but they were lowest during the warmer period of the year (April-September) (Tables VIII and VI.) The incidence varied considerably from herd to herd, but was not influenced by herd size (Table III). However, the level of hygiene exerted a pronounced influence on the incidence (Table VII), and self-contained herds had significantly lower death losses than had herds where female breeding stock was occasionally brought in (Table IX). Approximately 65 per cent of the pigs which succumbed due to gastrointestinal diseases died during the first week of life, which means that 1.8 per cent of the pigs at risk died during this period (Table X). The material was grouped according to the results of the post mortem and bacteriological examinations (Table XI). Approximately 50 per cent of the fatal cases were associated with an intestinal bacterial infection, which in most instances was caused by pathogenic strains of E. coli (Tables XII and XIII), while approximately 14 per cent had distinct gross pathological lesions which alone were indication of a diagnosis. In the remaining one third of the fatal cases the aetiology and pathogenesis remained by and large unexplained; however, nutritional and dietetic disorders played a role in many of these cases. Aetiological, epidemiological and pathological aspects of the fatal gastrointestinal diseases are discussed, and it is concluded that a high level of hygiene, the prevention and treatment of post parturient diseases, "closed" management systems, and the avoidance of unsuitable or damaged sow feed would be instrumental in keeping the level of fatal gastrointestinal diseases low among sucking pigs.
A 2-year study on preweaning mortality revealed that 2.1 per cent of the liveborn pigs succumbed to acute bacterial septicaemias. The most frequently encountered causative organisms were haemolytic streptococci and E. coli.
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The incidence and causes of polyarthritis in sucking pigs were studied in herds with 2,936 litters during a 2-year period. Among pigs more than 3 days old, the average morbidity rate was 3.3 per cent and the mortality rate amounted to 1.5 per cent (Table I). Among herds the morbidity ranged from 0.9 to 7.0 per cent and the mortality due to polyarthritis from 0.5 to 2.8 per cent. The incidences of polyarthritis were higher in the progeny of gilts than in the progeny of sows of other age groups (Table II). No consistens correlation between litter size at birth and the mortality rate due to polyarthritis was found (Table III). Cases of polyarthritis were observed in 17.8 per cent of the examined litters. Death due to polyarthritis occurred in 10.8 per cent of the litters (Table I); 67.3 per cent of the fatal cases occurred sporadically with only one pig lost per litter (Table IV). The mortality due to polyarthritis appeared to be higher in male pigs (Table V). An analysis of some possible contributory factors showed that the frequency of polyarthritis was adversely affected by new introduction of female breeding stock, clipping of the canine teeth and tail docking in the new-born, and by occurrence of skin diseases in individual piglets (Table VI, IX & XII). No obvious relation was found with such factors as: season of the year, sow's health condition, herd size (Table I), or hygiene level in the individual herds (Table VIII). Death due to polyarthritis occurred most frequently in pigs 2--4 weeks of age (Table X). The pathological lesions, which varied according to the duration of the inflammation and to the aetiology, are described. Arthritis was most frequently observed in the larger limb joints, although every joint may be affected (Table XI). In the majority of the cases a meningoencephalitis was present. A survey of other concomitant, complicating or possible predisposing lesions are presented (Table XII). The bacteriological examination of joints and other organs Table XIII) showed that haemolytic streptococci by far dominated as causative organism. Staphylococci species and E. coli were isolated from affected joints in 6.4 per cent and 4.3 per cent of the pigs, respectively. C. pyogenes and E. rhusiopathiae were rarely encountered in these sucking pigs with polyarthritis. Aspects of the epidemiology and pathogenesis are discussed in regard of minimizing the losses due to polyarthritis/meningitis in sucking pigs.
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