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PubMed2005

The use of homologous antigen in the serological diagnosis of brucellosis caused by Brucella melitensis.

In the European Union the serological diagnosis of brucellosis caused by Brucella melitensis is performed using the heterologous antigen of B. abortus S99. The possible higher sensitivity or ability of an early detection of antibodies by a homologous antigen may prove very useful in the final phases of an eradication programme. Results obtained in sheep experimentally infected by B. melitensis biovar 3 were compared using B. abortus S99, B. melitensis M1, M2 and M3 antigens in the Rose Bengal plate test (RBPT), the complement fixation test (CFT) and an enzyme-linked immunosorbent assay (ELISA) test. Forty-six sheep from an officially brucellosis-free flock were experimentally infected intraconjunctivally with B. melitensis biovar 3. Prior to infection, all animals were tested first against Brucella antibodies, weekly for 2 months post-infection (PI) and then monthly for a further 7 months. All sera were tested against the antigens listed above using RBPT, CFT and ELISA. Using a Bayesian approach, test sensitivities were estimated and compared. Their ability for the early detection of antibodies was evaluated through a regression model based on a logit response model, using the number of days PI as the independent variable and the logit of the fraction of positive animals as the dependent variable. No significant differences were detected among the various antigens used, either in terms of sensitivity or in terms of antibody kinetics; however, the CFT was significantly less sensitive than the RBPT and ELISA and it also showed a lower rate of increase of percentage positive animals (beta-coefficient of regression analysis).

Animals↗
PubMed1981

Experimental dicrocoeliasis: the humoral immune response of golden hamsters and rabbits to primary infection with Dicrocoelium dendriticum.

The results presented deal with the humoral immune response of golden hamsters to primary experimental infection with D. dendriticum. The development of serum antibodies has been comparatively investigated with three hamster groups (n = 43) harbouring different burdens of adult flukes. The mean numbers of parasites were 11, 30, or 130 per animal. Serum antibody response was studied during an observation period of at least 331 and up to 496 days postinfection. For antibody detection the sensitivities of precipitation test (PTs) (double diffusion test, immuno- and counterimmunoelectrophoresis), of the indirect haemagglutination test (IHAT), the complement fixation test (CFT), and the enzyme linked immuno sorbent assay (ELISA) were compared using aqueous crude fluke antigen and crude egg antigen. CFT and ELISA were most sensitive for the early detection of initial response. Thereafter all the tests employed revealed increasing antibody titres, which in general remained at constant levels and persisted until the end of the observation period with the exception of CF-antibodies. In general fluke antigen was found to be more sensitive than egg antigen. However, in CFT this antigen occasionally has been associated with unspecific inhibition of haemolysis. Comparison of the results shows that ELISA using crude fluke antigen gave the most realistic picture of the actual fluke burden. Also preliminary results on the precipitin response of rabbits (n = 3) after primary experimental exposure to different numbers of metacercariae (500, 1,000, and 3,000 per animal respectively) are reported. Employing the above mentioned PTs a persisting antibody response could be demonstrated only after exposure to at least 3,000 infective larvae. The initial response was found on day 63, the observation period was 550 days.

Animals↗
PubMed1990

Serological study of louse borne and flea borne typhus in Addis Ababa.

A total of 500 subjects (288 males and 212 females) were tested in Addis Ababa, Ethiopia, in Virology and Rickettsiology Division of the National Research Institute of Health, in 1987, for anti R. prowazekii using Complement Fixation Test (CFT). Out of these 58 subjects (41 males and 17 females) were also tested for anti R. typhi using the same test. The study population included three groups. Group I included 200 patients referred to the National Research Institute of Health (NRIH) for the Weil-Felix test for the diagnosis of typhus. Group II consisted of 200 patients with febrile illness visiting the Outpatient Department (OPD) of St. Paul's Hospital. Group III included 100 blood donors' serum samples included from previous collections. The blood donors had no sign of febrile illness during the collection of the blood samples. The results showed that anti R. prowazekii was detected in 38 subjects (7.6%). The sex ratio among the positive subjects indicated that there were 32 males (22%) and 6 females (2.8%). From the 58 subjects who were also tested for anti R-typhi only 7 (5 males and 2 females) (12%) were found to be positive. Only one person was found to be positive both for anti R. prowazekii and anti R-typhi. From 200 samples (Group-I) tested both by the Weil-Felix test and by Complement Fixation Test for anti R. prowazekii only 4 samples were positive by both test, thus showing very low percent agreement.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1997

Field evaluation of an indirect ELISA for detection of brucellosis in lowland Bolivia.

Bovine brucellosis exists endemically at an estimated prevalence of 10% in the developing dairy industry of Santa Cruz in tropical Bolivia. This paper describes field testing of an FAO/IAEA indirect ELISA for brucellosis, as a possible replacement confirmatory test for the complement fixation test (CFT). The ELISA and CFT were compared on sera from 3 cattle populations: a non-vaccinated negative population, an S19-vaccinated negative population, and a brucellosis-positive population of unknown vaccination status. The CFT and ELISA showed excellent specificities of 100% and 98% respectively against the negative non-vaccinated group. The CFT maintained a specificity of 98% against the S19-vaccinated negative group, but ELISA specificity fell to 83% using a cut-off of 20% of positive control, and 94% using a cut-off of 40% of positive control. Against sera from the positive population, the ELISA gave many more positive reactions than the CFT, probably a combination of both higher sensitivity and lower specificity. It is concluded that as Santa Cruz is entering a phase of brucellosis control rather than eradication, the extra sensitivity of the ELISA is not valuable enough to risk a higher level of false positive reactions, especially as S19 vaccination is being increasingly used.

Animals↗
PubMed1982

Differentiation of foot-and-mouth disease virus strains using a competition enzyme-linked immunosorbent assay.

Foot-and-mouth disease virus isolates were compared using solid-phase competition and indirect microenzyme-linked immunosorbent assays. Results were compared to those obtained from complement fixation tests. Similar relationships between the isolates were obtained using the indirect enzyme immunoassay and complement fixation tests. The competition assay was more discriminatory and the results did not always correlate with the other two assays.

Aphthovirus↗
PubMed1985

Anaplasma marginale infections in American bison: experimental infection and serologic study.

Anaplasma marginale was experimentally transmitted from cattle to bison and back to cattle. Of the 2 splenectomized and 1 intact American bison calves (Bison bison) inoculated with a North Texas A marginale stabilate, 1 splenectomized and 1 intact bison exhibited clinical signs of anaplasmosis. Active parasitemias in these bison were observed along with positive reactions in the rapid card agglutination and complement fixation tests. Blood from the infected bison produced disease in splenectomized bovine calves. Screening tests for anti-Anaplasma antibodies in 178 blood samples collected from adult bison from the National Bison Range, Montana, revealed 1 rapid card agglutination test-positive sample, and 110 negative, 40 suspect, and 28 positive (15.7%) complement fixation test samples.

Agglutination Tests↗
PubMed1985

Rapid rate-kinetic turbidometric assay for quantitation of viral complement-fixing antibodies.

A rapid rate-kinetic turbidometric assay for the quantitation of viral complement fixing antibodies has been developed, using adenovirus as a model. The procedure is based on the turbidometric quantitation of intact sheep erythrocytes and measures the rate of hemolysis (change in absorbance at 640 nm/min/), at maximum velocity, occurring in the presence of residual complement not fixed by the antigen-antibody reaction. Reagents were standardized and assays performed using a microprocessor-controlled spectrophotometer with kinetic assay capability and a thermoregulated cell compartment. Eleven sera were assayed for complement fixing antibodies both by the conventional microtiter technique and by the rapid turbidometric method described here. Good correlation (r = 0.89) was obtained between the two procedures. Unlike the conventional complement fixation test, the rate-kinetic turbidometric complement fixation assay was found to be tolerant of variation in complement and antigen concentration, endpoint titers were objectively quantitated and, once reagents had been standardized, results could be obtained within 45-60 min. The technique is potentially adaptable to large-scale automation.

Adenovirus Infections, Human↗
PubMed1978

[Micromethod of determining the complement-binding properties of commercial series of the foot-and-mouth disease virus].

Investigations were carried out to establish the possibility of using a micromethod of the complement-fixation test to determine the complement-fixing properties of productional series of the foot-and-mouth disease virus. It was found that the micromethod referred to is an economically profitable and practically simple one. It is readily applicable requiring no particular apparatuses and equipment, is specific, and can successfully be used instead of the routinely employed CFT method. The micromethod suggested is economical, requiring minimal amounts (0.025 cu.c7) of the components taking part.

Aphthovirus↗
PubMed1977

[Antibodies in rhesus-monkeys after experimental infection with African lung-worms (Paragonimus uterobilateralis and P. africanus) (author's transl)].

The following publication gives a report about serological studies on experimentally infected Macaca mulatta with Paragonimus uterobilateralis and P. africanus supplied by parasitological findings and chest X-ray experiments from other authors. It was shown that at first in the chronological sequence serological changes were noticed in the animals followed by X-ray changes of the lungs. Somewhat later the monkeys started with the excretion of worm-eggs. Egg production did not take place in all monkeys and was also very irregular from monkey to monkey. The passive haemagglutination and complement fixation test were suitable serological methods to indicate a Paragonimus infection in monkeys. It was shown that in older infections the complement fixation test is not as suitable as the passive haemagglutination since the complement fixing antibodies loose most of their activity within six to eight months. Antigenic relationship between the two African Paragonismus species could be demonstrated by cross-reactions with the passive haemagglutination, complement fixation and double gel diffusion test. Nevertheless by disc-electrophoretic experiment it could be proved that there were two taxonomically different Paragonimus-species in Africa.

Africa↗
PubMedDate not supplied

[The evaluation of a new complement fixation microtechnic (Garcia & Sotelo, 1991) for the diagnosis of chronic Chagas disease with different antigenic preparations].

From this present data it has been evaluated a new complement fixation test, comparatively to indirect immunofluorescence to diagnose chronic Chagas' disease, utilizing one watery extract of epimastigotes of Trypanosoma cruzi and three other ethanolic extracts: one from epimastigotes, one from tripomastigotes and a third one of amastigotes obtained from cultures. Utilizing 236 serum samples indirect immunofluorescence test was performed: 109 positives (20 of them with positive parasitologic diagnostic) and 127 negatives (96 of healthy blood donors and 31 with other diseases). The results have showed that is possible a positive reaction in diluted samples up to 1:16. The best limits of reactivity found were the dilutions 1:4 for the ethanolic extract of amastigotes and 1:2 for the others antigens. The correlation index among the new complement fixation test and indirect immunofluorescence test showed that the ethanolic extract from epimastigotes was the best antigen to be utilized to diagnosis purposes. Its co-positivity index with indirect immunofluorescence was 0.92207 and the co-negative index was 0.90000. Concluding, the new complement fixation test showed itself as a fast, sensible, easily applicable semiquantitative microtechnique to the diagnosis of chronic Chagas' disease.

Animals↗
PubMed1975

Virion and soluble antigens of japanese encephalitis virus.

Japanese encephalitis virions contain a 58 X 10-3-molecular-weight envelope glycoprotein antigen that can be solubilized with sodium lauryl sulfate and separated from other virion structural polypeptides and viral ribonucleic acid by gel filtration chromatography. The 58 X 10-3-molecular-weight envelope protein is the major antigen responsible for cross-reactivity of the virion in complement fixation tests with other closely related arboviruses. A naturally occurring soluble complement-fixing antigen is found in Japanese encephalitis mouse brain preparations after removal of particulate antigens. After partial purification by gel filtration and isoelectric focusing, the 53 X 10-3-molecular weight soluble complement-fixing antigen is more type specific than the Japanese encephalitis envelope antigen in complement fixation tests. Further, the Japanese encephalitis soluble complement-fixing antigen is stable to treatment with sodium lauryl sulfate and 2-mercaptoethanol, whereas virion complement-fixing antigens are unstable after this treatment.

Amino Acids↗
PubMed1982

Laboratory study of Mycobacterium bovis infection in badgers and calves.

Two experiments with badgers infected with Mycobacterium bovis are described. In the first, badgers were infected by intravenous inoculation of a bovine isolate of M bovis. The course of the disease in these and its spread to healthy badgers and calves was monitored by clinical, immunological and bacteriological means. In the second experiment a group of naturally infected badgers were observed for a period of up to four years. They were found to excrete M bovis in their faeces for periods of between 165 and 1305 days before they died of tuberculosis or were killed. M bovis was also shed in the urine. The badgers in both experiments were examined regularly and blood samples were taken for complement fixation tests. Faeces, urine, pus and sputum were also collected for cultural and biological tests and the badgers were skin tested using Weybridge bovine and avian tuberculin. The skin tests were uniformly negative while the complement fixation test were positive in some infected badgers but gave very variable results. Only the isolation of M bovis gave a definite diagnosis of tuberculosis in the living badger but a number of badgers which were found to have tuberculosis at post mortem were not detected while alive by this method. Environmental samples from the yards, including badger faeces, soil, hay, scrapings from feeding bowls and water were regularly examined for the presence of M bovis but apart from faeces only one water sample was positive, indicating that the organism did not persist for long in the environment. In both experiments calves developed sensitivity to bovine tuberculin after six months' exposure to infected badgers. The experiments further demonstrate the potential of a badger population to become endemically infected with M bovis and to act as a source of infection for cattle.

Animals↗
PubMed1978

Microneutralization tests for serological typing and subtyping of foot-and-mouth disease virus strains.

A microneutralization test for serotyping of FMD viruses is described. It is based on earlier observations by Booth, Rweyemamu & Pay (1978) that dose-response relationships in quantal microneutralizations often deviated from linearity. The typing test described therefore utilizes undiluted virus preparations. In about 90% of samples a positive typing was obtained in contrast with about 50% for the complement fixation test. The test was also found to be susceptible to minimal quantities of heterotypic viral contamination. For strain differentiation the microneutralization test was carried out as a checkerboard test. When compared with the complement fixation test it was found to be more specific. The necessity to utilize virus-neutralization test systems for comparing FMD virus strains particularly for the purpose of vaccine selection is emphasized. The two dimensional microneutralization test has been applied to a study of comparing FMDV vaccine strains for Europe, South America, the Middle East and East Africa.

Aphthovirus↗
PubMed1998

Evaluation of electrophoretic immunoblotting for Brucella ovis infection in deer using ram and deer serum.

AIMS: Recently the first case of natural infection of deer with Brucella ovis was discovered. The aim of this study was to develop and evaluate an electrophoretic immunoblotting method for testing deer serum for specific B. ovis antibodies. METHODS: An existing immunoblotting method for sheep serum was altered by using a recombinant protein G-alkaline phosphatase conjugate and Tris-buffered saline containing 3% non-fat dry milk powder for the blocking step and the serum and conjugate dilutions. The method was evaluated using 106 sheep sera from B. ovis - negative, accredited flocks, 69 sera from chronically infected rams shedding B. ovis in their semen, 110 sera from a B. ovis-infected flock, 18 sera from stags from which B. ovis was isolated, and 48 sera from deer flocks free from B. ovis infections. The immunoblotting method was applied to another 85 deer sera. RESULTS: The sensitivity of the new immunoblotting method was 98.6% for sheep and 94.4% for deer, and the specificity 99.1% for sheep and 100% for deer. Sixty-nine out of 97 deer sera, originating from the property from which the first B. ovis deer case had been reported, tested positive or suspicious in the complement fixation test. Of these, 53 sera exhibited staining patterns in blots typical for B. ovis infections and also one serum which was negative in the CFT. Only six out of 1498 deer sera. from throughout New Zealand had positive or suspicious reactions in the B. ovis complement fixation test. Of these, one exhibited a staining pattern in the blot suggestive of a B. ovis infection, while four showed patterns of suspicious reactions. CONCLUSION: The new immunoblotting technique is useful as a confirmatory serological test method for B. ovis infections in deer.

Journal Article↗