Biomedical subjects
Publications and source records attributed to E G Hartman.
The results of a bacteriological and serological study of the presence of L. hardjo on a dairy farm in view of a case of milk fever in a farmer are reviewed. In addition, the epidemiology, prevention and possible treatment of the infection on the dairy farm are discussed.
The clinical, pathomorphological and serological features of acute canine leptospirosis are evaluated and the IgM- and IgG-specific ELISA for leptospirosis serology in dogs is assessed. The clinical syndrome of acute canine leptospirosis was characterized by depression, anorexia, vomiting and often haemorrhagic diarrhoea. In addition, jaundice, uraemia, elevated creatinine and alkaline phosphatase were observed in the majority of the dogs. In pups invagination of the intestines was a noteworthy finding. The clinical signs and the post-mortem findings were rather non-specific so that the clinical and post-mortem diagnosis had to be confirmed serologically. In acute clinical cases of canine leptospirosis a high anti-leptospiral IgM titre, ranging from 160 in pups to 10240 in adults, was always present, whereas the anti-leptospiral IgG titre and the agglutination titre usually were negative or low. Dogs died from leptospirosis in spite of a high anti-leptospiral IgM titre. Only two dogs having, at the first examination, a high IgM titre in conjunction with a high IgG titre survived an acute infection. The possible role of IgM and IgG in the pathogenesis of an acute leptospiral infection is discussed. Different serological patterns in reference dogs, which were not suffering from acute leptospirosis, are presented.
The pathology of acute Leptospira interrogans serotype icterohaemorrhagiae infection in the Syrian hamster was investigated up to 7 days after infection using histology, electron microscopy and an indirect fluorescence test for leptospires. The disease was characterized by the presence of many leptospires in the tissues, jaundice, leukocytosis, haemorrhages, endothelial alteration and thrombotic glomerulopathy. The leptospires were present intravascularly, in the interstitium penetrating between liver cells and tubular epithelial cells and in the tubular lumina. The presence of leptospires was not necessarily associated with lesions. These findings support both pathogenetic mechanisms suggested in the literature, namely: the ability of leptospires to penetrate actively between cells with detachment of tight junctions, without obvious lesions to the cells, and an immune-mediated process with immune complex formation and binding and activation of complement resulting in leukocytosis, thrombotic glomerulopathy, endothelial alteration and haemorrhages.
A new chemotherapeutic agent, pipemidic acid, was used to treat 14 dogs and 2 cats with recurrent urinary tract infection caused by multiresistent strains of Escherichia coli and Proteus spp. Bacterial culture of the urine after treatment revealed disappearance of the microorganisms in all patients. It is concluded that pipemidic acid is a promising chemotherapeutic agent for urinary tract infections caused by multiresistant E. coli and Proteus spp., with the condition that bacterial culture during the course of treatment is obligatory.
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An enzyme-linked immunosorbent assay (ELISA) to detect antibodies to Leptospira interrogans serotype canicola in dogs was developed and evaluated. Comparison of the ELISA with the microscopic agglutination test (MAT) showed that, during the first two weeks after an experimental infection with serotype canicola, the ELISA detected antibody at higher dilutions than the MAT. After the second week post-infection both tests detected antibody at almost equal titres (r = 0.89). The outer envelope (OE) antigen of serotypes icterohaemorrhagiae, copenhageni and canicola was fairly serotype-specific, whereas the pellet (P) antigen showed more cross-reactivity. Both OE and P antigen of Leptospira biflexa strain Patoc I could be used as cross-reacting antigen in the ELISA. Compared to the MAT, the ELISA has some technical advantages. It is suggested that the ELISA would be useful as a screening test.
The development and evaluation of an enzyme-linked immunosorbent assay (ELISA) to detect specific anti-leptospiral IgM and IgG in sera of dogs experimentally infected with Leptospira interrogans serotype canicola are reported. In all dogs specific anti-leptospiral IgM was detected from the second half of the first week after infection, the maximum being attained during the second week. Subsequently the IgM titre gradually decreased. Specific anti-leptospiral IgG was detected later and increased gradually to reach almost the same level as the IgM titre after two to three months. During the initial stage of the infection, when the microscopic agglutination titre was still negative or very low, a high IgM titre was accompanied by a negative or very low IgG titre in every case. After the initial stage a substantial IgG titre was also detectable. It is suggested that the test is suitable for serodiagnostic purposes, particularly for the diagnosis of a current infection in an individual.
An IgM- and IgG-specific ELISA was used to measure the antibody response stimulated in dogs by vaccination with a leptospiral bacterin containing chemically inactivated Leptospira interrogans serotype icterohaemorrhagiae and serotype canicola leptospires. All dogs produced anti-leptospiral IgM and IgG. The IgM production was of the primary response type after each vaccination (primary vaccination, booster vaccination and annual revaccination). A substantial anti-leptospiral IgG response could be demonstrated only after the first booster vaccination and the annual revaccination. Annual revaccination resulted in a higher and much longer persisting IgG response than did the first booster vaccination. A revision of the vaccination scheme is suggested.
The epidemiology of canine leptospirosis has been examined in a limited study in the Netherlands from 1969 through 1982. Leptospira interrogans serotype icterohaemorrhagiae and canicola were found to be the only serotypes causing clinical leptospirosis. However, positive agglutination titres to the serotypes grippotyphosa, bratislava, poi and ballum have also been detected. The incidence of infection caused by serotype icterohaemorrhagiae was highest during summer and autumn. Infections with serotype canicola were more evenly distributed over the year with only a slight increase during summer and autumn. Infections caused by serotype canicola were significantly more prevalent in male dogs, whereas infections with serotype icterohaemorrhagiae were found both in males and females in almost equal numbers. The incidence of infections with serotype icterohaemorrhagiae was highest in immature dogs. Infections with serotype canicola were detected in young as well as older animals. In contrast to the situation in the past, infections with serotype icterohaemorrhagiae are now more common than those caused by serotype canicola, which have become rare. The highest incidence of infection was found in the western part of the country. The majority of infections was demonstrated in guard-dogs and sporting-dogs. Dogs proved to be of minor importance as a source of human infection in the Netherlands.
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The first observation of an outbreak of mastitis, caused by Mycoplasma bovis, in a dairy herd in the Netherlands is reported. The symptoms closely resembled those reported in the literature as being typical of mastitis due to Mycoplasma. The strain isolated was found to be sensitive to amongst others nifuroquine in vitro. Repeated intramammary application of Abimasten-100 containing nifuroquine resulted in the complete disappearance of mastitis in the herd.
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Leptospirosis is one of the most widely distributed zoonoses. Dogs are the pets in which leptospirosis is most common. The use of diagnostic laboratory procedures is discussed. During the first seven days of the disease, leptospires may be detected in the blood and organs; after the seventh day, they are detectable in the kidney and possibly also in the urine. Examination of the serum for antibodies is possible after the first week of the disease. A clinical diagnosis is often hard to establish. Unlike what used to be the case, infections with L. icterohaemorrhagiae are more common today than those with L. canicola. Infections are more common in male dogs than they are in bitches. In addition to antibiotic therapy, preferably consisting in administration of penicillin and streptomycin, symptomatic treatment is useful. Vaccination should be performed in the spring. Dog are probably of minor importance as a source of human infection in the Netherlands.
Comparative studies of the lysozyme test (LT) and the Schirmer tear test (STT) revealed that the LT was not reliable in the diagnosis of kerato-conjunctivitis sicca (KCS) in dogs and cats. This is in contrast to its successful use in human patients. No M. lysodeikticus lysating substrates were detectable in the tear fluid of the normal cat.
Leptospirosis in swine, caused by serotype lora (serogroup Australis) was detected both serologically and by culture. The most important symptoms consisted in abortion during the final month of gestation and the birth of dead or not viable piglets.
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This study describes a field trial in which 80 commercial layer flocks, with an increased risk of Salmonella enteritidis (SE) infection and placed on farms with a certified Standardized Biosecurity Programme (SBP) or a request for a SBP certificate, were vaccinated with a vaccine based on a live attenuated Salmonella gallinarum (SG) 9R strain. An evaluation is presented of the efficacy of the vaccine against SE infections, the effect on the performance of serologic Salmonella tests, and the spread of the vaccine strain to the egg content. For the efficacy study, assessment of the flock level occurrence of SE infections in the vaccinated group of 80 flocks was compared with that of a nonvaccinated group of 1854 flocks hatched in the same period. This control group was examined according to the compulsory control programme in The Netherlands. An evaluation was done of the performance of serologic Salmonella tests and the spread of the vaccine strain to the inner egg content of five of the vaccinated flocks. Findings demonstrated the flock level occurrence of SE infections in the vaccinated group (2/80 = 2.5%) to be significantly (P = 0.01) lower than that of the nonvaccinated group (214/1854 = 11.5%). Vaccination resulted in 59.0% positive test results in lipopolysaccharide BD enzyme-linked immunosorbent assay (ELISA) for detecting antibodies against Salmonella serogroups B and D and 0% positive test results in the rapid plate agglutination test for detecting antibodies against S. pullorum (SP)/SG. The mean specificities of two blocking ELISAs (gm- and i-double antibody sandwich ELISAs) based on the flagellar antigen of SE and Salmonella typhimurium (ST) on the same sera were 99.6% and 96.1%, respectively. The vaccine strain could not be isolated from any of the 450 pools of 10 eggs. On the basis of these results, we concluded that vaccination with a vaccine based on an attenuated SG 9R strain contributes to the reduction of SE infections in commercial layer flocks. Furthermore, serologic monitoring of SE, ST, and SP/SG can still be carried out on flocks vaccinated with an attenuated SG 9R strain. Additionally, we found no indication of the spread of the vaccine strain to the egg content.
A live vaccine based on an attenuated Salmonella gallinarum 9R strain is in use in a Salmonella enteritidis control program in commercial layer flocks in The Netherlands. In a field study, the potential spread of the vaccine strain from vaccinated flocks to nonvaccinated flocks has been studied after both the primary and the booster injection at four different rearing farms and at one layer farm. The vaccinated and the nonvaccinated flocks were monitored at regular intervals by bacteriologic and serologic examination. In this field study, no evidence was found for the fecal spread of the vaccine strain.