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Biomedical subjects

W A Ellis

Publications and source records attributed to W A Ellis.

At least 19 recordsLinked to original sources
PubMed2005

Reclassification of Leptospira parva Hovind-Hougen et al. 1982 as Turneriella parva gen. nov., comb. nov.

Analysis of the G+C content, DNA-DNA relatedness to other leptospires and 16S rRNA gene sequence of Leptospira parva showed that this species was not related to other Leptospira species. On the basis of these data, it is proposed that Leptospira parva should be transferred to the genus Turneriella as Turneriella parva gen. nov., comb. nov., with strain H(T) (=NCTC 11395(T)=ATCC BAA-1111(T)) as the type strain.

Bacterial Typing Techniques↗
PubMed2004

Microbiological and serological study of leptospirosis in horses at slaughter: first isolations.

A bacteriological survey of kidneys from 145 abattoir horses was performed, which resulted in the isolation of two Leptospira strains. The isolates were serologically typed as belonging to serogroups Australis and Pomona, and REA identified them as L. interrogans serovar Bratislava and L. kirschneri serovar Tsaratsovo, respectively. These are the first Leptospira isolates obtained from horses in Portugal and the Bratislava strain is the first serogroup Australis strain to be isolated in this country. The 145 horses were also serologically tested for leptospiral antibodies, and 37% had MAT titres #10878;1:10.

Agglutination Tests↗
PubMed2001

Detection of chlamydial antibody by fetal serology--an aid to the diagnosis of ovine abortion.

Two serological tests (indirect immunofluorescence and enzyme-linked immunosorbent assay) were developed for the detection of fetal antibody to Chlamydia psittaci. Fetal blood and thoracic fluid from 126 field cases of suspected ovine chlamydial abortion were examined using both tests. Placenta and fetal tissues (lung, liver, and kidney) from the same animals were also examined by the following conventional diagnostic methods: isolation in McCoy cells, detection of chlamydial lipopolysaccharide (LPS), modified Ziehl-Nielsen staining, and direct fluorescent antibody staining of chlamydia in frozen cryostat sections. Seventy cases were positive by fetal serology, and of these, 68 were also positive by isolation and/or LPS detection. The remaining 56 cases had negative fetal serology, and of these, 39 were positive by isolation and/or LPS detection. Results indicate that fetal serology, although less sensitive than either isolation in McCoy cells or detection of chlamydial LPS antigen, may be of particular use when placenta is not available.

Abortion, Veterinary↗
PubMed1999

Stillbirth/perinatal weak calf syndrome: a study of calves infected with Leptospira.

Leptospiral infection has been reported in calves which were either stillborn or dead from perinatal weak calf syndrome; 356 such calves were examined for evidence of associations between leptospiral infection and macroscopic, histological and microbiological findings, and the parity of the dam. Calves in which leptospiral antigen was detected in the placenta were significantly lighter by an average of 6 to 10 kg than calves with no antigen in the placenta. Calves infected with Leptospira were more likely to be infected by Actinomyces pyogenes or Bacillus species. No other significant associations were detected. The adrenal gland, lung and placenta were the most useful organs to examine for leptospiral antigen. The placenta was the only antigen-positive tissue 8.9 per cent of the calves submitted with their placenta.

Abortion, Veterinary↗
PubMed1999

Development of an ELISA to detect antibodies to a protective lipopolysaccharide fraction of Leptospira borgpetersenii serovar hardjo in cattle.

Monoclonal antibodies (Mabs) were produced against Leptospira borgpetersenii serovar hardjo-type Bovis antigens. A panel of 28 Mabs were characterised. Only the nine Mabs toward a lipopolysaccharide (LPS) fraction of 18, 24 kDa bands and a 26-28 kDa smear showed agglutinating, leptospiricidal and growth-inhibition activities, and passively protected hamsters against renal infection with hardjo. They also reacted strongly in the CH-ELISA, captured killed whole hardjo leptospires, gave good fluorescence in indirect FAT against smears of hardjo culture and exhibited no cross reactivity with strains in heterologous serogroups. On the basis of optimal activity in a range of tests, one IgG class Mab (designated 25) was selected for use in an antibody-capture ELISA system for the detection of bovine anti-hardjo antibodies. The system gave a wide separation of absorbance values between positive and negative sera at a 1:10 dilution. The antibodies detected by this assay are believed to be protective anti-LPS IgG.

Agglutination Tests↗
PubMed1997

Experimental reproduction of iodine deficiency in cattle.

The role of iodine deficiency in stillbirth/perinatal weak calf syndrome was investigated in pregnant heifers. Five heifers were fed an iodine deficient diet (mean [sd] iodine concentration 0.06 [0.01] mg/kg dry matter [DM]) and six received an iodine sufficient diet (mean [sd] iodine concentration 1.45 [0.27] mg/kg DM). The diets consisted of wheat and soyabean meal with added minerals and vitamins (with or without iodine) and were fed to the heifers over the final four to five months of pregnancy. The iodine deficient diet produced clinicopathological changes and pathological changes in the thyroid glands of both the heifers and their offspring. However, all the calves in the iodine deficient group were born clinically normal.

Animal Nutritional Physiological Phenomena↗
PubMed1997

Magnetic immuno capture PCR assay (MIPA): detection of Leptospira borgpetersenii serovar hardjo.

Magnetic immuno PCR assay (MIPA) was developed for the rapid detection of leptospires excreted in urine samples (n = 59) collected from 35 experimentally infected cattle. The immunomagnetic separation of leptospires from inhibitors in frozen formalin fixed bovine urine prior to PCR detection resulted in a marked improvement on previous detection methods. MIPA is a rapid 5 step protocol requiring 70 mins preparation time prior to amplification, which consistently detects 10(1) organisms. MIPA detected 76% (38/50) of culture positive urines and in addition three urines that were culture negative were shown to be positive by this method of detection. Consequently we conclude that whilst MIPA is an improvement on previously published PCR detection methods, the culture of the organism is still the standard against which other detection methods have to be compared.

Animals↗
PubMed1996

Reduced conception rates in dairy cattle associated with serological evidence of Leptospira interrogans serovar hardjo infection.

Fertility data from 673 cows in five dairy herds with a moderate to high seroprevalence of microscopic agglutination titres (MAT) of > or = 1:10 against Leptospira interrogans serovar hardjo were collated to assess the relationship between pregnancy rates and antibody titres to serovar hardjo. A significant proportion of failures of conception (10 to 13 per cent, P < 0.001) were associated with MATs of 1:10 to 1:100; the overall pregnancy rate of the seronegative cows was 28.5 per cent higher (P < 0.001) than that of the cows with MATs of > or = 1:100. First service pregnancy rates showed a similar trend but the differences were significant (P < 0.05) only in cows with antibody titres > or = 1:30. An assessment of other possible risk factors for reduced pregnancy rates, such as lactation number and calving to first service interval, had no effect on the statistical results of the study or its conclusions.

Animals↗
PubMed1996

Stillbirth/perinatal weak calf syndrome: a study of calves with an abnormal thyroid gland.

Data collected from 365 calves dead from stillbirth/perinatal weak calf syndrome were analysed to determine the predictive value of thyroid gland weight as an indicator of abnormality of the thyroid gland, and to examine the relationships between abnormality of the thyroid gland and other findings in the calves and also the parity of the dam. There was a significant relationship (P < 0.001) between the thyroid gland weight and bodyweight for the calves with a histologically normal thyroid gland, but there was no such relationship for calves with an abnormal thyroid gland. Only 1.1 per cent of the histologically normal thyroid glands weighed more than 30 g, indicating that there is a very high probability that glands weighing more than 30 g are abnormal. However, 76.0 per cent of moderately to severely affected glands weighed less than 30 g. The following significant differences between calves with an abnormal and those with a normal thyroid gland were established. Abnormal thyroid glands were significantly heavier (P < 0.01), constituted a significantly greater percentage of the calf's bodyweight (P < 0.01) and had a significantly lower iodine concentration (P < 0.001). A significantly higher proportion of calves with an abnormal thyroid gland had uninflated lungs (P < 0.01), and a significantly higher proportion had pneumonia (P < 0.01). Abnormal thyroid glands were associated with a low selenium concentration in the kidneys. There were no associations between abnormalities of the thyroid gland and the parity of the dam, the presence of skeletal fractures, the weight or sex of the calf, infection with leptospira, Salmonella dublin, Bacillus species, Actinomyces pyogenes or Aspergillus species, the quantities of hepatic iron pigment, liver vitamin E concentration or serum cholesterol concentration.

Animals↗
PubMed1996

Reproductive performance of dairy herds infected with Leptospira interrogans serovar hardjo relative to the year of diagnosis.

To assess the impact of Leptospira interrogans serovar hardjo infection on the reproductive performance of nine dairy herds with evidence of infection, forty years' fertility data were analysed relative to the year of first diagnosis. Fifty per cent of various fertility variables had their lowest values only in the year of diagnosis. Culling rates were highest during the year of diagnosis in five of the herds, and were above 22 per cent in five of nine (55-6 per cent) of the diagnosis years considered compared with seven (22-6 per cent) of the 31 non-diagnosis years. An assessment of the fertility status of the herds by means of a formula with incorporated the first service conception rate, the number of services per conception for cows conceiving, the calving to conception interval and the culling rate, revealed low reproductive performance during the year of diagnosis in six of the nine herds. Abortion rates were highest in four of the herds during the year of diagnosis, and these included the herds in which the fertility status was not lowest. It was concluded that L. interrogans serovar hardjo affected reproductive adversely by causing both abortions and low fertility, but that the effect was temporary.

Abortion, Veterinary↗
PubMed1996

Presence of antigen and antibodies in serum and genital discharges of heifers after experimental intrauterine inoculation with Leptospira interrogans serovar hardjo.

The excretion of Leptospira interrogans serovar hardjo in cervico-vaginal mucus (CVM) or urine and the local and systemic immune responses to the organism were monitored in eight susceptible heifers after intrauterine inoculation while six similar heifers served as controls. All the heifers were inseminated at the subsequent oestrous periods. The overall percentage pregnancy rate (the number of pregnancies divided by the total number of inseminations) was lower in the infected heifers than in the controls though not significantly (33.3 v 50.0 per cent). Leptospires were detected, in either the urine or the CVM of six of the eight infected heifers during the study period of 15 weeks, either by direct immunofluorescence or dark ground microscopy; the bacteria did not grow in culture from any of the CVM samples. The control heifers remained free from evidence of infection. In the infected heifers, mean titres of at least 1:100 in a microscopic agglutination test were maintained for one to two weeks before declining to 1:10 to 1:30, whereas in serum IgG-ELISA tests (developed by using either protein or carbohydrate antigens), antibody titres of at least 1:100 were maintained throughout the study. During oestrous periods, IgA antibodies were detected more frequently in CVM with titres which were usually higher than the titres of IgG.

Agglutination Tests↗
PubMed1996

Presence of antigen and antibodies in serum and genital discharges of cows from dairy herds naturally infected with Leptospira interrogans serovar hardjo.

Samples of cervico-vaginal mucus from 163 bulling cows (group 1) and post calving discharges from 59 newly calved cows (group 2) in five dairy herds naturally infected with Leptospira interrogans serovar hardjo were examined for the presence of antigen and IgG and IgA antibodies by using two ELISA systems which were protein or carbohydrate based. Corresponding serum samples were examined for systemic immune responses by using a microscopic agglutination test (MAT) and IgG-ELISA tests. Antigen was detected by direct immunofluorescence in six of the 163 samples of cervico-vaginal mucus. Both IgG and IgA antibodies were detected by ELISA in the genital discharges with a prevalence much higher than that obtained by the MAT but lower than that observed with the serum IgG-ELISA. Combining both groups, none of the MAT-positive cattle was negative by serum-ELISA. By using the protein or carbohydrate fraction serum IgG-ELISA assays, respectively, 29 or 41 per cent of the MAT-negative cows were positive at a titre of at least 1:40. Similarly, eight or 23 samples (10 or 27 per cent) had titres of at least 1:20 in the genital discharge ELISA for IgG and IgA antibodies, respectively. The serum IgG-ELISA was the most efficient in detecting hardjo antibodies, but in group 2 the IgG- and IgA-ELISA of the post calving discharge proved to be equally effective.

Animals↗