Biomedical subjects

C Staak

Publications and source records attributed to C Staak.

At least 19 recordsLinked to original sources

PubMed1998

Detection of Brucella species in organs of naturally infected cattle by polymerase chain reaction.

A polymerase chain reaction (PCR) assay was used to detect Brucella species in the uterus, udder, spleen, lymph nodes, kidney and liver of three cows which had been naturally infected in an outbreak of brucellosis, and the results were compared with the results of bacteriological investigations. All 18 samples reacted positively in the PCR, but five samples had weak bands after the electrophoretic separation of PCR mixtures. No Brucella strains could be detected in these five samples by bacterial cultivation, but all the other samples gave positive results. A pre-enrichment procedure was necessary for the PCR. A PCR with DNA from eight Yersinia strains gave no amplification product.

Animals↗

PubMed1998

Host preferences of tsetse (Diptera: Glossinidae) based on bloodmeal identifications.

An enzyme-linked immunosorbent assay (ELISA) was developed to identify the origin of vertebrate blood in the guts of 29 245 wild-caught flies of eleven Glossina species from various ecological zones of Africa. Depending on the quality of the bloodmeal samples, 62.8% of the samples were identified and could be assigned to a host-group (e.g. ruminant), family (e.g. Bovidae) or species (e.g. Bos spp.). A total of 13 145 samples (44.9%) was identifiable up to the species level. With a few exceptions, the present results are in agreement with earlier published reports. Glossina austeni and G. fuscipleuris seemed to have a distinct feeding preference for Suidae (mainly bushpig). Glossina morsitans ssp. fed mainly on Suidae (mainly warthog), although local variations were observed and in some areas hippopotamus or ruminants replaced the warthog as the main host. Bushbuck seemed to be the principal food source for G. longipalpis and G. fusca. Glossina pallidipes fed mainly on ruminants (buffalo, bushbuck and cattle) but, depending on host availability and location, Suidae were also important hosts. Hippopotamus was identified as the main source of bloodmeals for G. brevipalpis. The main hosts for G. longipennis were Suidae (mainly bushpig) and not rhinoceros as had been reported 40 years earlier. The opportunistic feeding behaviour of the palpalis tsetse group was confirmed. The results showed that changes in environment, fauna and host availability may result in modification of tsetse feeding patterns.

Animals↗

PubMed1997

Serological crossreactivity between Brucella abortus and Yersinia enterocolitica 0:9. III. Specificity of the in vitro antigen-specific gamma interferon test for bovine brucellosis diagnosis in experimentally Yersinia enterocolitica 0:9-infected cattle.

The course of immunological reaction in 10 Yersinia enterocolitica 0:9 experimentally-infected heifers was followed using the conventional brucellosis tests complement fixation test (CFT), serum agglutination test (SAT) and brucella card test (BCT), and a recently developed Brucella antigen-specific gamma interferon (IFN-gamma) test. Initially, the animals were exposed orally to 10(10) colony-forming units (CFU) of Y. enterocolitica 0:9. Four weeks later, they were inoculated intravenously with 10(8) CFU of Y. enterocolitica 0:9 cells. After oral inoculation, the response in the conventional brucellosis tests was minimal. Only after intravenous inoculation were CFT and SAT titres and BCT reactions comparable to natural, false positive brucellosis reactors. After oral exposure the Brucellergen-stimulated release of IFN-gamma peaked at values above the cut-off stimulation index of 2.5 in 80% of the heifers. After intravenous inoculation, stimulation indices above 2.5 were present in only 10% of the animals. Two B. abortus infected control cattle showed stimulation indices of 3.1 and 3.4, and a negative control animal exhibited a stimulation index of 1.0. These findings show, in contrast to a previous study, that the Brucellergen-specific IFN-gamma assay cannot be used as a specific and discriminatory test for B. abortus infections.

Animals↗

PubMed1997

The importance of cattle as a food source for Glossina morsitans morsitans Katete district, Eastern Province, Zambia.

The feeding habits of Glossina morsitans morsitans in the Eastern Province of Zambia were studied. A total of 687 meals were identified. Results show that 75.1% of the meals were taken on cattle. These results are discussed in relation to the published data on feeding patterns of Glossina morsitans morsitans and the control of tsetse or tsetse-transmitted trypanosomosis in the study area.

Animals↗

PubMed1997

[Comparison of the results from commercially available Brucella ELISA test kits for the investigation of bovine sera].

Bovine sera from a farm with bacteriologically confirmed brucellosis were taken for comparative serological studies using conventional methods (slow agglutination test--SAT, complement fixation test--CFT, Rose-Bengal-plate-agglutination-test--RBPT) and 5 different commercially available brucellosis ELISA testkits. These serum samples together with other infectious sera producing low level positive antibody titers in conventional tests did not react uniformly when tested by five different commercial ELISA testkits. The introduction of a standard control serum with a general cut-off resulted in a greater uniformity of ELISA results from 4 of 5 ELISA testkits and a closer approach to results of the CFT which is regarded as the confirmatory test for brucellosis. This control serum, on the other hand, was not suitable for the identification of the sensitivity of the various ELISA test kits. For this purpose, in SAT and CFT weakly positive reacting brucella sera from infected farms is needed.

Agglutination Tests↗

PubMed1996

Polystyrene as an affinity chromatography matrix for the purification of antibodies.

Affinity chromatography is used for the purification of diagnostic polyclonal antibodies in order to ensure specificity. Most commonly, activated bead-formed agarose or its derivatives are used as gel matrices. Alternative matrix materials have been described, but as yet they do not appear to offer important advantages. In this study, pulverized polystyrene (PS 158K, BASF, Mannheim, Germany) was used as a solid phase for the immobilisation of bovine immunoglobulins (Ig). Affinity chromatography was performed using these coated polystyrene beads as the column matrix material in the purification of anti-bovine Ig. The polystyrene binding capacity for the different bovine Ig classes was compared using the Mancini single radial immunodiffusion technique, and ELISA procedures were used to monitor the antibody reactivity of purified and unpurified antibodies. The degree of purification was comparable to the most commonly used procedure using gel matrices from activated bead-formed agarose (e.g. CNBr-activated Sepharose 4B, Pharmacia/LKB Biotechnology, Uppsala, Sweden), but the antibody yield per ml column volume was distinctly lower. In order to raise the yield, such polystyrene bead columns with immobilized antigen can be re-used without loss of activity or larger column volumes can be used to raise the binding capacity. The polystyrene material is quite durable, chemically and immunologically inert and has a long shelf life. We conclude that polystyrene based affinity chromatography is efficient, simple and cheap.

Adsorption↗

PubMed1996

World Health Organisation--supervised interlaboratory comparison of ELISAs for the serological detection of Salmonella enterica serotype Enteritidis in chickens.

A collaborative exercise, supervised by the World Health Organisation, was set up to compare ELISAs used for the serological detection of Salmonella enteritica serotype Enteritidis in chickens. The aim was to ascertain how far agreement could be reached on the interpretation of optical density readings for high titre, intermediate titre and low titre sera. Two sets of sera were sent to 14 participants. The first set compared high, medium and low titre sera raised in specified-pathogen-free and commercial broiler breeder chickens. The second set comprised 20 sera of different antibody titres raised in commercial birds reared under laboratory conditions and sent blind. Both indirect and double-antibody sandwich blocking ELISAs were used with a number of different detecting antigens. With a few exceptions good agreement was reached on the interpretation of results obtained from high and low titre sera from the optical density obtained with a single serum dilution. Differences were observed in the interpretation of medium titre sera. The results suggested that most ELISAs produce reasonably comparable results and that practical problems may arise from interpretation of the results mainly as a result of the choice of the criteria used for differentiating sera obtained from infected and uninfected chickens. These problems are discussed.

Animals↗

PubMed1995

Copro-antibody in calves from dams vaccinated against Salmonella typhimurium.

Calves received colostrum either with (positive colostrum) or without (negative colostrum) anti-Salmonella typhimurium antibodies. Regarding the detectability of copro-antibodies, the following observations have been made. In calves that had been given positive colostrum on day 4 post natum (p.n.), copro-antibodies were detectable over 7 days, while in those that had received positive colostrum on day 1 p.n. copro-antibodies were detectable over 45 days. After supplying highly positive colostrum, copro-antibodies were found over a period of 8 weeks, and after supplying weakly positive colostrum, they were found over a period of 5 weeks. It is concluded that serum antibodies are transferred to the intestine for maximum local protection, and that there exists a preference for the intestinal system regarding the distribution of salmonella antibodies. Challenge infection on day 5 p.n. of calves that had received highly positive colostrum resulted in a copro-antibody gap that reached the limit of detectability in two calves that were excreting salmonellas. Challenge infection of calves that had received negative colostrum provoked a local IgM and IgA antibody response.

Animals↗

PubMed1994

Host blood meals and chromosomal inversion polymorphism in Anopheles arabiensis in the Baringo District of Kenya.

Studies were carried out in the villages of Kapkuikui and Maji-Ndege in the Loboi area of Baringo District, Kenya, to obtain baseline data on species identification of the Anopheles gambiae group, their feeding and resting behavior, and their frequencies of chromosomal inversions. This was carried out towards predicting the effect of introducing permethrin-impregnated cloths or other intervention measures. In this study, Anopheles arabiensis was identified as the only species of the An. gambiae group. This species contained 2 inversions, 2Rb and 3Ra, occurring at frequencies ranging from 55 to 60%, and from 5 to 11%, respectively. There was no evidence for nonrandom mating. Indoor- and outdoor-collected samples were significantly different in respect of inversion 3Ra in one village and in the distribution of the different sources of blood meals in both areas. In these villages, 37% of indoor-resting mosquitoes fed outside before entering houses to rest.

Animals↗

PubMed1994

[The hosts of Glossina fuscipes fuscipes Newstead, 1910 (Diptera: Glossinidae) in 2 animal breeding zones in the Central African Republic].

From 1987 to 1993, a survey on the feeding behavior of Glossina fuscipes fuscipes was conducted in the Central African Republic. A total of 556 blood-meal samples was analyzed by ELISA. According to the results, the number of blood meals from cattle was rather low (12% on average). During the rainy season, this number increased significantly and varied according to the sampling area. Along the riverine forests, this amounted to 5%, while blood meals from wild ruminants amounted to 87%. In the neighborhood of watering-places, the number of cattle blood meals reached 9-22%. Reptiles were found to be important hosts (17-35%). In all cases, man presented a non-negligible host (4-14%), similar to suidae (2-19%). The authors discuss the relevance of these results to risk of trypanosomes transmission.

Animals↗

PubMed1993

Course of infection and humoral immune reaction in calves infected orally with different Salmonella serovars.

5 groups of five calves each were orally infected with the salmonella serovar S. agona, S. dublin, S. enteritidis, S. infantis or S. typhimurium. The course of infection and the humoral immune response against 5 antigen preparations of the homologous and the 4 heterologous salmonella serovars were monitored in each group. Antibodies against two different protein antigens and against two differently prepared LPS antigens were determined by ELISA and the level of H-agglutinin was assessed by micro agglutination test. All 5 serovars proved to be virulent for calves. The specificity of antibodies produced following the infection are not always consistent with the Kauffmann-White scheme. There was a relation of age and strain for infection on immune response, whereas the severity of infection did no correlate with an increase of antibody production. The serological tests used were good for investigation of a defined host-parasite-interaction but not satisfactory for serovar specific diagnosis of salmonella infection in cattle.

Animals↗

PubMed1992

[Bovine colostrum and protection of young animals].

An insufficient absorption of colostrum-immunoglobulins (Ig) by the newborn calf may result in morbidity and mortality at the early age of 1-2 weeks after birth. According to a study from California, such losses amounted to 20% in dairy herds. Ig-deficiencies were observed in almost 90% of all calves which died within the first week of their lives. The rapid identification of Ig-deficient calves, compensation by feeding colostrum from another dam or the application of relevant commercial products from the dairy industry are attempts to remedy such a situation. Feeding bovine colostrum to lambs, kids, foals and piglets, bovine Ig is readily absorbed into the blood-system of these animals. Vaccination of pregnant animals aims at the provocation of specific antibodies for the protection of the offspring. The application of the vaccine into the mammary gland at ablactation provokes specific IgA- and IgM-antibodies which are normally not channelled from the blood system + of the mother into the colostrum. The advantage of the vaccination of pregnant animals is the immediate provision of protecting antibodies for the newborn immuno-incompetent animal. Under the pressure of an increasing criticism against the routinely applied supplementary feeding of antibiotics, this kind of immunization may reach more and more of importance. Like non-specific Igs, specific colostrum-Igs are absorbed into the blood-system of newborns from other animal species.

Animal Diseases↗

PubMed1990

[Immunologic memory in the course of udder immunization for the protection of calves against Salmonella infections].

Cows were vaccinated once or twice intracisternally in order to protect calves against salmonella infections. The amount of antibodies measured in the colostrum of re-vaccinated and not re-vaccinated cows indicated that a sensitive immunological memory has been provoked by this vaccination technique. This immunological memory showed a distinct synchronism with the state of pregnancy in order to provide a maximum amount of antibodies in the colostrum.

Animals↗

PubMed1990

Serological reactions of leptospirosis-positive (MAR and CFT) bovine sera in ELISA.

The collection of test sera for measuring ELISA results was composed of bovine sera with MAT titres of greater than or equal to 1:200 in the leptospirosis MAT and of greater than or equal to 1:5 in the CFT together with sera from a serologically negative and clinically non-suspicious cattle herd. To establish cut-off ODs, the geometric mean net-extinction of the negative serum collection plus 1, 2, and 3 standard deviations were calculated. By comparison of 3 different conjugates from rabbits, it was demonstrated that results from anti-total bovine Ig were superior to anti-IgG and anti-IgM conjugates. Considerations regarding sensitivity and specificity led to the recommendation to use a test serum dilution of 1:160, to apply anti-total bovine Ig conjugates, and to establish the cut-off OD at the geometric mean net-extinction of negative sera plus 3 standard deviations. Under such conditions, agreement between leptospirosis MAT/CFT positivity on the one side and ELISA positivity on the other was reached in 74%. This recommendation is made for cross-sectional studies but not for examinations of clinically suspicious cattle herds.

Agglutination Tests↗

PubMed1990

Natural hosts of Glossina tachinoides (Diptera: Glossinidae) in northern Côte d'Ivoire.

Bloodmeal samples of G. tachinoides were taken at the Comoé National Parc in northern Côte d'Ivoire. The total of 1154 identified samples consisted mainly of ruminants (37%, whereof bushbuck represented 57%), hippopotamus (34%), and monitor lizard (19%). These proportions changed with the seasons. In the rainy season the portion of hippopotamus samples increased, whereas that of reptiles decreased. Primate blood was identified only in samples taken in the dry season.

Animals↗

PubMed1990

[A simple method for the isolation of immunoglobulin (Y) from the eggs of immunized hens].

Hens were vaccinated with Salmonella typhi-murium and with serum-IgG from a goat. Antibodies (IgY) were isolated from the eggs by ammonium sulphate precipitation. The concentration of egg antibodies was equal or superior to the concentration of serum antibodies of the hen. The longlasting antibody plateau of 9 and 28 weeks, respectively, provides evidence of the high yields of specific IgY which can be collected from a single immunized hen.

Animals↗

PubMed1990

[Udder immunization for the protection of calves from salmonella infections. 2. Estimation of serological findings of colostrum with regard to its protective activity].

Colostrum from cows which had been mammary gland vaccinated against salmonellosis were tested for antibodies by four different serological tests. Results from these tests were related to the protective activity for artificially infected calves. In opposition to agglutinating antibodies and antibodies detected by ELISA, complement fixing antibodies of the IgG1 class were shown to transfer early protection in artificially infected calves.

Animals↗

PubMed1989

Fractionation of trypanosome antigens for species-specific sero-diagnosis.

Crude somatic antigens from isolated and ultrasonically treated trypanosomes were fractionated by column chromatography. A protein-free antigenic fraction was isolated which reacted monospecifically when tested against hyperimmune sera from rabbits. The method has a potential application in the improvement of serodiagnosis of trypanosomiasis.

Animals↗