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Biomedical subjects

C Staak

Publications and source records attributed to C Staak.

At least 19 recordsLinked to original sources
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↗
PubMed1989

The host preferences of Chrysops silacea and C. dimidiata (Diptera: Tabanidae) in an endemic area of Loa loa in the Congo.

The analysis of 404 blood meals from Chrysops silacea and C. dimidiata which had been collected in the forests of the Chaillu mountains (People's Republic of the Congo) has demonstrated for the first time that both species also feed on non-human hosts. For both species the feeding patterns are fairly similar. However, man remains the main host in 89-90% of the cases. C. silacea and C. dimidiata took 6 and 4% respectively of their blood meals from hippopotamuses, 2 and 0% from rodents, 2 and 4% from wild ruminants, and 0.8 and 0.7% from monitor lizards. Whenever a differentiation has been made between the different members of the primates, only meals from humans but not from chimpanzees or baboons have been detected. The results may provide an explanation for the distinct barrier between the simian and human loiasis infections. They also give evidence for the ability of both vectors to travel over prolonged distances.

Animals↗
PubMed1989

[Udder immunization for the protection of calves against salmonella infections. 1. Detection of specific Ig classes in the mother, colostrum and calf and the course of infection].

Pregnant cows were vaccinated at ablactation by infusion of heat inactivated S. dublin or S. typhimurium into the mammary gland in order to protect their offsprings via colostrum against salmonellosis. This method of vaccination is based upon statements according to which specific IgA and IgM play a prominent role in respect of protection. Both Ig classes are produced locally and are not channelled from the mother's system into the mammary gland. In comparison to calves from non-vaccinated control animals, calves from vaccinated cows did not exhibit clinical symptoms after challenge infection, and had a reduced salmonella excretion rate in respect of quantity but not in respect of the duration of shedding salmonella. Serological quantitation of specific Ig-classes (DIG-ELISA) did not allow to identify a specific Ig-class responsible for protection.

Animals↗
PubMed1988

The feeding habits of the tsetse, Glossina pallidipes Austen on the south Kenya coast, in the context of its host range and trypanosome infection rates in other parts of east Africa.

The results of blood-meal identifications for 651 Glossina pallidipes from 5 subpopulations near the Kenya coast south of Mombasa, and one, 70 km inland, are presented. Bushpigs and/or warthogs were important hosts for G. pallidipes at all sites. Other major hosts included elephant, buffalo and bushbuck where they were present, and on a dairy ranch nearly 30% of feeds were taken from cattle. There was a general relationship between the numbers and diversity of wild herbivores and the abundance of G. pallidipes. These results are discussed in relation to published data on feeding patterns and trypanosome infection rates for G. pallidipes from other parts of East Africa. Overall, there are significant correlations between the proportions of bovid feeds and T. vivax infections. Bovid-feeding G. pallidipes populations with high T. vivax infection rates in south-east Uganda and western Kenya contrast with the coastal, suid-feeding populations with low T. vivax rates. These characteristics are presented as clines extending across East Africa.

Africa, Eastern↗
PubMed1985

Trypanosoma evansi infection in buffaloes in north-east Thailand. I. Field investigations.

Clinical, parasitological and serological findings of Trypanosoma evansi infections in buffaloes (Bubalis bubalis) from north-eastern Thailand are reported. The overall infection rate was found to be around 20% with a distinct peak of acute infections during the rainy season. The disease is aggravated by normally well tolerated concomitant infections such as liver fluke infestations and by other stress factors.

Animals↗
PubMed1984

Bovine brucellosis among two different cattle populations in Bahr el Ghazal Province of Southern Sudan.

During a serological Brucella survey in Bahr el Ghazal Province (Southern Sudan), 6.5% of a total of 5982 randomly selected cattle of the Dinka tribe from 303 herds investigated showed positive results. Herds of bigger size were found to be more frequently infected than smaller herds. From 1228 randomly selected cattle of the Fellata tribe (Red Bororo race), 22.5% produced a positive reaction. Here, reactors were detected in 71 from a total of 72 herds tested (98.5%). Among the Dinka cattle, the number of reactors rose steadily in correspondence to the age of the animals. A somewhat more pronounced increase of reactors was observed in animals 4-8 years of age. On the other hand, the number of reactors in the Fellata herds increased rapidly between the age of 2-4 years. Thereafter, this infection rate did not change significantly any more. The results indicated that a significant portion (37.1%) of reactors graded positive (n = 665) expressed only low titers (less than or equal to 1:40) in the SAST. Those titers were even more numerous (49.1%) among the positive reactors belonging to cattle below the age of 4 years.

Agglutination Tests↗
PubMed1984

Use of formaldehyde-PBS for serum dilution in the microscopic agglutination test (MAT) for leptospirosis.

Altogether, 431 sera (381 positive and 50 negative sera) were tested against different Leptospira serovars in the microscopic agglutination test (CMAT) using PBS with and without formaldehyde for comparative purposes. For the preparation of serum dilutions with formaldehyde-PBS, formaldehyde was added to PBS at a final concentration of 0.4%. When retested after storage, 234 from the 381 formerly positive sera gave positive, 68 doubtful and 79 negative results in the MAT. Out of the 234 sera with positive reaction in MAT, 212 (90.6%) showed positive reactions in the MAT with formaldehyde as well, 19 (8.1%) doubtful reactions and 3 (1.3%) became negative. All sera with negative reaction in the routine MAT were found to be negative in the MAT with formaldehyde as well.

Agglutination Tests↗
PubMed1979

The complement fixation test and African trypanosomiasis: I. Experimental infection and re-infection in cattle before and after treatment.

The complement fixation test was applied to assess antibody responses in cattle infected with T. brucei, T. congolense, and T. vivax which had been treated and re-infected. After the first infection, the specificity of the results was low in T. congolense, fair in T. brucei, and high in T. vivax infected animals. After re-infection with the same trypanosoma species as used for previous infections, the specificity of CF results was high in all cases. After a foregoing T. vivax infection, specific titres of T. congolense and to a lesser degree of T. brucei infections were frequently masked by residual T. vivax titres. After treatment of trypanosoma-infected cattle the fasted drop of CF antibody titres occurred in T. congolense cases, followed by T. brucei infections. T. vivax titres persisted over prolonged periods.

Animals↗
PubMed1979

The complement fixation test and African trypanosomiasis. II. The complement fixation test as an aid for assessing therapy.

Complement-fixing antibody titres decline after successful treatment of trypanosoma infected cattle during a fixed period. For investigating the practicability of the resulting double test procedure in the field, cattle under controlled drug regimes were tested at treatment and again 3 weeks later. Alternatively, the results from groups of treated and untreated animals from the same area were compared. Both serological and parasitological test results indicated an insuffieicnt effectiveness of therapy in the area under investibation.

Animals↗