Fifty years of leptospirosis research in New Zealand: a perspective.
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Journal Article↗
Biomedical subjects
R B Marshall
Publications and source records attributed to R B Marshall.
Observations of leptospirosis in farmed deer.
AIMS: Slaughterhouse and on-farm surveys were undertaken to investigate some aspects of leptospirosis (Leptospira interrogans) in farmed deer in the lower North Island of New Zealand. METHODS: Blood samples and kidneys were collected at slaughter from 601 l-year and older red and red X Wapiti stags and 21 adult hinds from 53 farms (10 or 12 deer per farm). Serum samples were analysed for up to seven Leptospiral serovars. Gross and histological examinations of kidneys were undertaken. Kidneys from 202 deer were cultured for leptospires. A follow-up postal questionnaire (68% response) indicated one herd had been vaccinated prior to the survey. Serological analyses were also carried out on serum bank samples from a previous on-farm survey involving male and female weaner, yearling and adult red deer from 16 commercial deer farms in March and November. RESULTS: Serological reactions at titres > or = 96 to serovar hardjo were present in 73.6%, pomona in 41.5%, copenhageni in 11.3% and tarassovi in 15.1% of farms from the slaughterhouse survey. Antibodies to serovars australis, ballam and balanica were present in three, one and four of six herds studied, respectively. Titre prevalence to hardjo was higher than that of pomona and other serovars within farms. Cultures for Leptospira were positive in 10 stags from six lines with similar prevalence across age groups. Histological examination showed many gross lesions were associated with mild interstitial cellular infiltration characteristic of subclinical Leptospiral infections. Some sections from culture-positive kidneys contained spirochetes in renal tubules. The on-farm survey showed a 10-30% within-herd prevalence of pomona and hardjo titres in 56% of 3-month-old deer herds, but by 11 months of age, 100% of herds were titre-positive with high prevalences to one or both serovars. Concurrently, herds of 1-year-old and adult deer on the same farms were all seropositive. CONCLUSION: This study has shown that Leptospiral infections are common in farmed deer in the survey area.
Journal Article↗
Impact of Yersinia enterocolitica enteritis on disaccharidase activity and small intestinal morphology in colostrum-deprived newborn piglets.
The effect of enteritis on the development of the small intestine was examined in newborn, colostrum-deprived piglets infected with a human isolate of Y. enterocolitica (serotype 0:3, biotype 4) soon after birth. The piglets were killed 3 days (n = 6) or 5 days (n = 8) after infection, or antibiotic therapy was commenced on day 5 and the animals killed on day 14 (n = 5). Compared with the non-infected controls, infected animals had reduced mucosal lactase and sucrase, but not maltase activity, while after antibiotic therapy, previously infected piglets had a lower lactase and a higher maltase and sucrase activity. Lactase activity was significantly reduced in the duodenum and jejunum, and mean values were lower in the ileum, but the difference did not reach significance; maltase activity was greater at all ages from the distal jejunum to the mid-ileum; sucrase activity was reduced in all segments up to day 5 but after antibiotic therapy was increased in the jejunum and appeared early in the ileum. Enzyme profiles were more mature along the crypt-villus axis in some segments of the intestine in previously infected piglets. Sodium-potassium-ATPase activity was unchanged. There was a reduced villus height:crypt depth ratio, crypt hyperplasia and increased crypt cell proliferation. Morphological maturation, indicated by loss of vacuoles and location of the nucleus at the base of the enterocyte, proceeded distally from the duodenum to ileum from 3 to 14 days of age when only the ileum remained immature. In infected piglets, there was reduced vacuolation and earlier location of the nucleus at the base of the cell in the distal intestine. Accelerated maturity of specific disaccharidases and enterocyte morphology in infected piglets appears to be due to physical damage to the mucosa resulting in faster proliferation of crypt cells and migration of enterocytes. It is suggested that this may reduce macromolecular internalisation and impair the ability to utilise dietary carbohydrate and may have long-term effects on growth and immunological responses of the gut.
Journal Article↗
The epidemiology of Leptospira interrogans serovar pomona in grower pig herds.
An epidemiological study on four farms showed that leptospiral infection became apparent in piglets from 12 weeks of age. The intensity of leptospiruria was greatest in the first 3-4 weeks of infection and from then on declined and became intermittent. Factors affecting the cultural and serological prevalence of infection of the piglets were found to be the standard of hygiene and variations in the titre of the dam. Dams with high titres gave better protection to their young than did those with low titres. The spread of infection within piggeries was encouraged by mixing infected with uninfected pigs, which resulted in epidemics within the pens. Transmission from infected to susceptible grower pigs continuously occurred in grower houses, with a constant proportion of pigs becoming infected each week.
Journal Article↗
Experimental infection of newborn piglets with Yersinia enterocolitica: an animal model of enteritis.
Newborn, colostrum-deprived Large White piglets infected with a human isolate of Yersinia enterocolitica biotype 4 serotype 0:3 were used as an animal model of yersiniosis. Within 3 hours of birth and before being fed, 14 piglets were inoculated orogastrically with 10 ml of bacterial suspension containing about 3 x 10(10) colony forming units of Y. enterocolitica, followed by 10 ml of 10% NaHCO3 solution. A further 14 litter mates acted as controls. The animals were reared on an artificial milk formula and humanely killed at 3 or 5 days after infection. Of the 14 infected piglets, 11 became anorexic, five vomited and 13 developed diarrhoea. Yersinia enterocolitica was isolated from their faeces and small intestinal contents. Body weight gains and the plasma glucose concentrations were significantly lower in the infected piglets than in the controls. Damage to the mucosa was observed in the whole gastro-intestinal tract, but was more severe in the small intestine and caecum. Micro-abscesses surrounding bacteria were present at the base of the villi in all parts of the small intestine, particularly in the distal ileum. Lesions were present in the small intestine in all infected piglets by day 3 and were more extensive by day 5. The liver was damaged by day 5, but not day 3. Similar lesions were seen in the mucosa of the stomach in one of six piglets at 3 days and in two of eight piglets at 5 days. It is hypothesised that the hypoacidity in the newborn stomach, as well as the administration of the NaHCO3 solution, may have produced favourable conditions for bacterial invasion.
Journal Article↗
The role of wild birds and the environment in the epidemiology of Yersiniae in New Zealand.
A survey was carried out to determine the prevalence of Yersiniae in wild passerines in the lower half of the North island of New Zealand over a period of 12 months. Samples of soil, water and foliage were also collected. Out of a total of 1370 avian samples, only two strains of Y. pseudotuberculosis were isolated and a total of 98 strains of environmental yersiniae were identified, including Y. enterocolitica biotype 1a, Y. frederiksenii, Y. kristensenii and Y. intermedia. No strains of Y. pseudotuberculosis were isolated from 1032 non-avian samples collected, which included 100 samples taken from wild mammals. From the non-avian samples, 51 strains of environmental Yersiniae were identified, of which the relative prevalence of Yersinia enterocolitica, biotype 1a, Y. frederiksenii, Y. kristensenii and Y. intermedia was similar to that in the rural passerines. The prevalence of Yersiniae in soil samples was greater in rural areas than in urban areas of the survey region. In both rural and urban passerine populations, the prevalence of Yersiniae was greater in the winter and early summer than at other times of the year.
Journal Article↗
Effects of Yersinia enterocolitica infection on growth of the body and internal organs in newborn colostrum-deprived piglets.
Yersinia enterocolitica enteritis in newborn, colostrum-deprived piglets fed a human milk formula caused a reduced milk intake and decreased gain in weight but not length of the body. In infected piglets, the weight of the liver was less than in controls but other abdominal organs were unaffected. The weight of the caecum and small intestinal muscle were greater, but the length and weight of the small intestine and colon were not different. In infected piglets, the RNA concentration of the small intestinal mucosa was elevated whereas the concentrations of DNA and protein were unchanged, and total lactase activity was reduced. After antibiotic therapy, the liver weight was greater and the body weight increased at the same rate as the controls but was still lower at 14 days. The body weight of the control piglets increased linearly over the 14 days after birth. The stomach, pancreas and spleen grew more rapidly, but the liver more slowly, than the body as a whole but the kidneys had a minimum relative weight at 5 days. The total lactase activity and protein and RNA concentrations of the small intestinal mucosa decreased with age, the RNA to a greater extent than the protein.
Animals↗
A case of human Leptospira canicola infection in New Zealand.
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Letter↗
Genetic characterization of pathogenic Leptospira species by DNA hybridization.
A total of 66 serovars of potentially pathogenic Leptospira species were examined by slot blot hybridization, and 57 of these serovars were classified in six DNA homology groups. In cases in which common serovars were studied, the results were in general agreement with the results of previous workers, who used different DNA homology methods. However, we propose a new species, Leptospira kirschneri, comprising the following serovars: bulgarica, butembo, cynopteri, dania, grippotyphosa, kabura, kambale, ramisi, and tsaratsovo. Seven of these serovars have not had their DNAs studied by other workers.
DNA, Bacterial↗
A study of the heterogeneity of isolates of Mycoplasma ovipneumoniae from sheep in New Zealand.
To investigate the heterogeneity of Mycoplasma ovipneumoniae, sixty isolates from three sheep on each of twenty farms were examined by restriction endonuclease analysis (REA) and SDS-PAGE. All were found to be different except for three isolates obtained from one farm. The protein and REA patterns of individual isolates were both highly reproducible and remained unchanged following long term passage (approximately 400 generations) in vitro. No plasmids were detected in the twelve strains which were examined and when two isolates were co-cultured in vitro, no genetic interchange, as judged by changes in REA patterns were detected. Since the heterogeneity of M. ovipneumoniae when examined by SDS-PAGE is too great to allow groups to be recognised, it could be advantageous for this purpose if only surface proteins were compared. As a preliminary step to this end we have identified several surface proteins of M. ovipneumoniae and found that some are common to all strains, one surface protein was shared by five of the eight strains examined and another was unique to one strain. This approach has the potential to allow the recognition of grouping of M. ovipneumoniae isolates.
Animals↗
The isolation of multiple strains of Mycoplasma ovipneumoniae from individual pneumonic sheep lungs.
The heterogeneity of Mycoplasma ovipneumoniae isolates from the lungs of sheep with chronic non-progressive pneumonia (CNP) from the same flock raised the possibility that multiple isolates derived from one lung were not all identical. To test this hypothesis, thirty isolates were obtained from each of six pneumonic sheep lungs at slaughter. Four lungs had relatively severe lesions and from each of these, three or four strains of M. ovipneumonia, distinguishable by REA and in most cases by SDS-PAGE, were detected. From the lungs of each of two sheep with mild lesions, two strains of M. ovipneumoniae were detected. Four isolates from one lung were further examined by restriction endonuclease analysis (REA) using many restriction endonucleases. Those which differed with EcoRI also differed when other restriction endonucleases were used. However, partial digests occurred mainly with those restriction endonucleases which recognise cytosine-rich sequences. The presence of multiple strains of one species of microorganism in individual lesions is an unusual concept which may not be limited to one disease or to one host.
Animals↗
Flow cytometric DNA analysis of normal and pathologic parathyroid glands.
Assessment of cellular DNA content and cell cycle analysis by flow cytometry has been useful in predicting patient survival and the malignant potential of many neoplasms. In this study, we analyzed the DNA content and cell cycle distribution of 12 parathyroid adenomas, 15 carcinomas, 5 secondary hyperplasias, and 14 normal parathyroid glands. Appropriate areas demonstrating the pathologic changes were dissociated from paraffin-embedded, formaldehyde-fixed tissue for this purpose. All the cells from normal glands were diploid with mean and median S-phase fractions of 1.2% (range, 0.3-2.7%). Of the 18 glands from five patients with secondary hyperplasia, 4 (22%) had some cells which were aneuploid (from three patients), and 14 (78%) had only cells with a diploid DNA content. Mean and median S-phase fractions were 0.8% (range, 0.3-1.5%). One (8%) of the adenomas was tetraploid, 3 (25%) were aneuploid, and 8 (67%) were diploid. The mean S-phase fraction was 1.5% (range, 0.3-3.8%). Four (27%) of the carcinomas had tetraploid cells, 6 (40%) had aneuploid cells, and 5 (33%) had only diploid cells. Carcinomas had a mean S-phase fraction of 6.0% (median, 5.3%; range, 1.4-14.1%). This study indicates that DNA aneuploidy or tetraploidy may be present in many abnormal parathyroid entities, but not in normal parathyroids. Proliferative activity when considered with the DNA index may be a helpful adjunct in separating carcinomas from adenomas or hyperplasias.
Adenoma↗
Islet cell neoplasms. A fine-needle aspiration cytology study with immunocytochemical correlations.
Islet cell neoplasms (ICNs) are uncommon tumors that may present with bizarre endocrine manifestations. Only rarely have their fine-needle aspiration (FNA) cytomorphologic characteristics been reported. The authors have studied FNAs of ICNs in ten patients, including immunocytochemistry (ICC) directly on the aspirates. FNA yielded moderately to markedly cellular specimens with numerous individual cells and large aggregates. Although moderate pleomorphism was present in three cases, striking uniformity in nuclear size and contour and in delicate nuclear membranes was evident. Typically the round nuclei were eccentric, imparting a plasmacytoid appearance. Cytoplasmic granularity was noted in only a minority of tumor cells. Five of the ICNs were positive for chromogranin (CG). In comparison, seven ICNs were positive for CG in tissue sections. None of the cytologic material showed immunoreactivity with insulin, glucagon, somatostatin, or gastrin. Histologic material showed positivity for these hormones in 33% (three of nine), 22% (two of nine), 22% (two of nine), and 11% (one of nine), respectively. Although CG is the most useful immunocytochemical marker for ICNs, and thus is helpful in confirming a diagnosis of ICN in FNA material, it is negative in half of the cases and may be negative when the histologic material is positive.
Adenoma, Islet Cell↗
DNA relatedness among strains of Leptospira biflexa.
The slot blot method of DNA hybridization was used to study 38 strains of Leptospira biflexa belonging to 38 serovars. Fifteen of these serovars were placed into six groups. The remaining 23 serovars were generally too diverse to show significant DNA relatedness either to these groups or to one another. Serovar thracia was related to Group 5, but it was not included in this group because its percent relatedness was too low. We found that genetically related organisms were antigenically dissimilar. The absence of any significant genetic relationship between Leptonema illini and the Leptospira biflexa serovars tested supports the placement of the former species in a separate genus.
DNA, Bacterial↗
Staying afloat during restructuring storms.
By 1988 Jack Pfister could see the writing on the wall. His 80-year-old utility company, the Salt River Project (SRP), would no longer be sheltered from competition's chill wind. Its special status as a governmental entity was being challenged by emerging deregulation in the power industry. "Foreign" producers could now wheel their surplus power into his backyard at bargain rates.
Hospital Restructuring↗
Tuboovarian pregnancy associated with elevated maternal serum alpha-fetoprotein. A case report.
Tuboovarian implantation is a rare form of pregnancy that is difficult to diagnose in early gestation. A patient with a tuboovarian pregnancy presented with abnormally elevated initial screening maternal serum alpha-fetoprotein (MSAFP). The elevated MSAFP and a pelvic mass of uncertain etiology on ultrasonography delayed the diagnosis until laparotomy was performed. Elevated MSAFP accompanied by oligohydramnios and a pelvic mass is a particularly suspect finding for a tuboovarian or other type of extrauterine implantation.
Adult↗
Species differentiation of Leptospira interrogans serovar hardjo strain Hardjobovis from strain Hardjoprajitno by DNA slot blot hybridisation.
Slot blot hybridisation studies with total genomic DNA probes were used to compare Leptospira interrogans serovar hardjo strain Hardjoprajitno, strain Hardjobovis and a number of other Leptospira interrogans serovars. Strains Hardjoprajitno and Hardjobovis were found to have little genetic relationship with each other when compared to some of the other serovars tested. Hardjoprajitno is closely related to serovar icterohaemorrhagiae and not to Hardjobovis whereas Hardjobovis is closely related to serovars vietnam, balcanica and javanica but not to serovar icterohaemorrhagiae; this places strain Hardjoprajitno in the species L interrogans and strain Hardjobovis in the species L borgpetersoni. Because of this lack of genetic relatedness between strains Hardjoprajitno and Hardjobovis, it is proposed to remove the prefix Hardjo from the strain name Hardjobovis and call it L borgpetersoni serovar hardjo strain Bovis.
Animals↗