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Use of hamster antisera in the preliminary differentiation of Leptospira interrogans servars hardjo and balcanica.

Preliminary differentiation of Leptospira interrogans serovars hardjo and balcanica can be made with antisera that are collected from hamsters after experimental infection with serovar hardjo and selected for high homologous and low or nil heterologous titres, as measured by the microscopic agglutination test. Rabbit antisera against serovars hardjo and balcanica, cattle antisera against hardjo and sheep antisera against the serogroup Hebdomadis each agglutinated hardjo and balcanica to a similar titre.

Agglutination Tests↗

The route of entry of leptospires into the kidney tubule.

To study the migration of Leptospira interrogans serotype pomona through the kidney, conventionally-reared mice aged 2 or 3 weeks were infected intraperitoneally with this organism. Within the first 4 days, the organisms migrated from the capillary lumina to the interstitial tissue and provoked an interstitial oedema. By the 10th day they were seen between the epithelial cells of the proximal convoluted tubules and by the 14th day many were located within tubular lumina. There was no evidence of viable leptospires within the cells of the proximal tubules, though occasionally structures resembling leptospiral fragments inside lysosomes were observed. At no stage during the study were glomerular lesions seen.

Animals↗

Neither hippurate-negative Brachyspira pilosicoli nor Brachyspira pilosicoli type strain caused diarrhoea in early-weaned pigs by experimental infection.

A hippurate-negative biovariant of Brachyspira pilosicoli (B. pilosicolihipp-) is occasionally isolated in diarrhoeic pigs in Finland, often concomitantly with hippurate-positive B. pilosicoli or Lawsonia intracellularis. We studied pathogenicity of B. pilosicolihipp- with special attention paid to avoiding co-infection with other enteric pathogens. Pigs were weaned and moved to barrier facilities at the age of 11 days. At 46 days, 8 pigs were inoculated with B. pilosicolihipp- strain Br1622, 8 pigs were inoculated with B. pilosicoli type strain P43/6/78 and 7 pigs were sham-inoculated. No signs of spirochaetal diarrhoea were detected; only one pig, inoculated with P43/6/78, had soft faeces from day 9 to 10 post inoculation. The pigs were necropsied between days 7 and 23 after inoculation. Live pigs were culture-negative for Brachyspira spp., but B. pilosicolihipp- was reisolated from necropsy samples of two pigs. The lesions on large colons were minor and did not significantly differ between the three trial groups. In silver-stained sections, invasive spirochaetes were detected in colonic mucosae of several pigs in all groups. Fluorescent in situ hybridisation for genus Brachyspira, B. pilosicoli and strain Br1622 was negative. However, in situ detection for members of the genus Leptospira was positive for spirochaete-like bacteria in the colonic epithelium of several pigs in both infected groups as well as in the control group. L. intracellularis, Salmonella spp., Yersinia spp. and intestinal parasites were not detected. The failure of B. pilosicoli strains to cause diarrhoea is discussed with respect to infectivity of the challenge strains, absence of certain intestinal pathogens and feed and management factors.

Animals↗

Infectious causes of acute pancreatitis.

A wide variety of infectious agents has been associated with acute pancreatitis. Strict diagnostic criteria were developed to assess with relationship between individual microorganisms and acute pancreatitis. Pathologic or radiologic evidence of pancreatitis associated with well-documented infection was noted with viruses (mumps, coxsackie, hepatitis B, cytomegalovirus, varicella-zoster virus, herpes simplex virus), bacteria (Mycoplasma, Legionella, Leptospira, Salmonella), fungi (Aspergillus), and parasites (Toxoplasma, Cryptosporidium, Ascaris). Clues to the infectious nature of pancreatitis lay in the characteristic signs and symptoms associated with the particular infectious agent. How often these agents are responsible for idiopathic pancreatitis is unclear.

Bacterial Infections↗

Leptospirosis in the causation of hepato-renal syndrome in and around Pune.

Fifty cases of hepato-renal dysfunction of unknown etiology were studied over a two-year period. Urine samples were examined microscopically and cultured for Leptospira. Serum samples were examined for antibodies against Leptospira by the Macroscopic slide agglutination test (MSAT). Seventeen out of fifty patients (34%) showed evidence of Leptospiral infection by at least two diagnostic techniques used. 15/17 i.e. 88.2% were positive by dark ground microscopy, 7/17 were diagnosed by culture technique and 16/17 i.e. 94% were confirmed by serology. There was a good correlation between Microscopic agglutination test (MAT) and MSAT. Thus Leptospires seem to play a major role in the causation of hepato-renal dysfunction in and around Pune, Maharashtra.

Adult↗

Vaccine-associated canine distemper infection in a litter of African hunting dogs (Lycaon pictus).

Four, 57 days old, African hunting dog puppies (Lycaon pictus) from one litter died within three weeks following vaccination with modified-live canine distemper virus (CDV) and killed canine adenovirus type 1, canine parvovirus and Leptospira icterohemorrhagiae and canicola. 18 days post vaccination, the animals developed neurologic disease characterized by episodes of grand mal seizures and circling. Macroscopic, histological and immunohistochemical studies revealed acute systemic CDV infection with acute encephalopathy. Virus isolation attempts using primary dog kidney cells, lung macrophages and Vero cells were negative. Therefore, the question whether the infection was the result of vaccination or natural infection remains open. The benefits and risks regarding the use of modified-live CDV vaccines and killed canine distemper vaccines in exotic carnivores are briefly discussed.

Animals↗

[The Pavia Center for the study and diagnosis of leptospirosis].

According to his deep experience in this field, the Author greatly appreciates the program agreed during this congress. He thinks that Leptospirosis is a still widely diffused zoonosis, for which accurate diagnostic work-up is requested, coupled to an adequate epidemiologic study. Among his own contributions to this argument, the A. remarks the studies on the experimental infection of the guineapig with L. icterohaemorrhagiae, providing evidence that jaundice and lethal course of the illness are due to the Leptospira and not, as it was currently supposed, to an overcoming Staphylococcal septicemia. Furthermore the A. observed a striking epidemic by L. pomona affecting 90 out of 120 rice-workers in the neighbourhood of Pavia. This Leptospira, previously unreported in Europe, was found to be carried by Norvegian rats captured in that country. These data were in contrast with the more frequent incidence, in this work environment, of L. bataviae, carried by Micromis minutus sorcinus. Following the amount of observations and researches in this field "Center for study and diagnosis of Leptospirosis" was founded in 1954, and is still working in Pavia. The necessity of isolation of the infective agent, in addition to the simple serologic study, was claimed by the observation of five cases of meningitis in young pigherds, in which L. canicola (instead of the more common L. pomona) was demonstrated and îelded from the CSF of a patient. In the field of veterinary medicine, the A. demonstrated the L. australis A as responsible of some cases of miscarriages in openair breeded cattle. In those cases the hedgehog (Erinaceus europeus) was the natural carrier.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Diseases↗

Efficacy of macrolides and telithromycin against leptospirosis in a hamster model.

Human studies support the use of beta-lactams and tetracyclines in the treatment of leptospirosis. Additional agents from these and other classes of antimicrobials also have in vitro activity against Leptospira species, though corroborating in vivo data are limited or lacking. We evaluated the therapeutic efficacy of azithromycin, clarithromycin, and telithromycin in a lethal hamster model of leptospirosis using Leptospira interrogans serogroup Canicola serovar Portlandvere. A range of dosages for each antimicrobial was given to the infected animals on days 2 through 7 (5 days) of the 21-day survival model. All untreated control animals survived less than 10 days from infection. Ninety to 100% of doxycycline controls, treated for 5 days with 5 mg/kg of body weight of drug, survived to 21 days. Treatment with azithromycin (daily dose: 6.25, 12.5, 25, 50, 100, or 200 mg/kg) resulted in 100% survival at all evaluated doses. Animals receiving 20 mg/kg or more of clarithromycin (daily dose: 1, 5, 10, 15, 20, 40, 60, or 100 mg/kg) had improved survival. Ninety-eight percent of animals treated with telithromycin (daily dose: 1, 5, 10, 15, 20, or 40 mg/kg) survived. We conclude that all agents tested have demonstrated in vivo efficacy in treating acute leptospirosis. These results provide support for further evaluation of macrolide and ketolide antimicrobial agents in human trials.

Animals↗

Ocular manifestations in the acute phase of leptospirosis.

OBJECTIVES: To study the ocular manifestations during the acute phase of leptospirosis and their incidence in hospitalized patients due to systemic complications, and to verify the importance of routine ophthalmologic care in these cases. METHODS: Twenty-one patients, 20 males and 1 female, with clinical and laboratory (ELISA IgM) diagnoses of leptospirosis were subjected to ophthalmologic examination. RESULTS: We observed conjunctival hyperemia in 18 patients (85.7%), increased retinal venous caliber in 12 patients (57.1%), optic disc redness in 12 patients (57.1%), subconjunctival hemorrhage in four patients (19.0%), optic disc edema in one patient (4.8%), retinal vasculitis in one patient (4.8%), retinal hemorrhage in one patient (4.8%), hard exudates in one patient (4.8%), and papillitis in one patient (4.8%). No anterior chamber reaction was found. CONCLUSIONS: We observed a high incidence of several ocular manifestations in the acute phase of leptospirosis. Despite the systemic severity and high incidence of ocular disorders in the acute phase of leptospirosis, the short-term visual outcome of these patients was good.

Acute Disease↗

Protective killed Leptospira borgpetersenii vaccine induces potent Th1 immunity comprising responses by CD4 and gammadelta T lymphocytes.

Leptospira borgpetersenii serovar hardjo is the most common cause of bovine leptospirosis and also causes zoonotic infections of humans. A protective killed vaccine against serovar hardjo was shown to induce strong antigen-specific proliferative responses by peripheral blood mononuclear cells (PBMC) from vaccinated cattle by 2 months after the first dose of vaccine. This response was absent from nonvaccinated control cattle. The mean response peaked by 2 months after completion of the two-dose vaccination regimen, and substantial proliferation was measured in in vitro cultures throughout the 7 months of the study period. Variations in magnitude of the response occurred among the vaccinated animals, but by 7 months postvaccination there was a substantial antigen-specific response with PBMC from all vaccinated animals. Up to one-third of the PBMC from vaccinated animals produced gamma interferon (IFN-gamma) after 7 days in culture with antigen, as ascertained by flow cytometric analysis, and significant levels of IFN-gamma were measured in culture supernatants by enzyme-linked immunosorbent assay. Two-color immunofluorescence revealed that one-third of the IFN-gamma-producing cells were gammadelta T cells, with the remaining cells being CD4(+) T cells. The significance of this study is the very potent Th1-type immune response induced and sustained following vaccination with a killed bacterial vaccine adjuvanted with aluminum hydroxide and the involvement of gammadelta T cells in the response. Moreover, induction of this Th1-type cellular immune response is associated with the protection afforded by the bovine leptospiral vaccine against L. borgpetersenii serovar hardjo.

Animals↗

Benign leptospirosis: first reported outbreak in British Isles due to strains belonging to the Hebdomadis serogroup of Leptospira interrogans.

The clinical and epidemiological features associated with the first reported outbreak in the British Isles of benign anicteric leptospirosis, due to strains belonging to the hebdomadis subgroup, are described. Four cowherdsmen working in two dairy farms in Surrey developed a febrile illness which was not associated with jaundice, but aseptic meningitis was a feature. Microscopic agglutination tests with formolized antigen suspensions revealed a significant rise in the agglutinin titres against various serotypes belonging to the hebdomadis serogroup of Leptospira interrogans. The probable source was eventually traced to the cattle, which showed serological evidence of infection with the same serogroup.

Adult↗

[Endemic and imported severe leptospirosis (Weil's disease) in southern Switzerland].

We report on 4 cases of severe icteric leptospirosis. Three patients developed renal failure requiring haemodialysis and one required mechanic ventilation for 10 days. On entry all patients presented with severe myalgia, particularly in the calves, jaundice, oligo-anuria and severe thrombocytopenia. In one case an acute abdomen-like presentation led to exploratory laparotomy. We believe that the abdominal pain was mainly due to rhabdomyolysis of the abdominal wall. The outcome was favorable in all cases and recovery of renal function was observed after a few days to several weeks. Three out of 4 patients were infected in southern Switzerland. This observation underscores the importance of wild and domestic animals as a leptospira reservoir. Patients presenting with acute renal failure and jaundice, but only mild-to-moderate elevation of transaminases, are suspect for leptospirosis regardless of travel to a tropical or subtropical country.

Acute Kidney Injury↗

Seroprevalence of and risk factors for leptospiral antibodies among cattle in the state of Yucatan, Mexico.

Sera obtained from cattle in the state of Yucatan, Mexico, were screened using the microscopic agglutination test against 13 serovars of Leptospira interrogans. A total of 62.8% (461/734) cows were positive for one or more serovars. This seroprevalence probably reflects infection because vaccination against leptospirosis has not been practised in Yucatan. The most common antibodies detected were those against antigens of serovars hardjo (54.1%) and tarassovi (53.3%). Region was the only risk factor associated with the seroprevalence of leptospirosis (p < 0.05).

Agglutination Tests↗