Serogroup Sejroe Research Articles

Prevalence and serovars of leptospira involved in equine abortions in central Kentucky during the 1991-1993 foaling seasons.

In this study, the prevalence of leptospira-induced abortions/stillbirths for the past 3 foaling seasons (1991-1993) was determined, and fetal tissues and/or the mare's urine from positive cases were cultured in an attempt to isolate and identify the leptospira serovars responsible for the abortions. The sensitivity and specificity of the primary diagnostic tests, the fluorescent antibody test (FAT) and the microscopic agglutination test (MAT), used for the diagnosis of leptospirosis were also determined. For the 3 years, 74 (3.3%) of 2,264 abortion/stillborn submissions were diagnosed as leptospirosis. Twelve cases occurred in the 1991, 19 in the 1992, and 43 in the 1993 foaling seasons. Leptospires were isolated from 45 (60.8%) of the 74 cases, and they were identified as serovar kennewicki (43 cases), serovar grippotyphosa (1 case), and a serovar similar to pomona (1 case). Of the 29 culture-negative cases, serologic results indicated that leptospires in the Pomona serogroup (kennewicki is a member of this serogroup) were responsible for 25 abortions, leptospires in the Grippotyphosa serogroup for 1 abortion, and leptospires in the Sejroe serogroup for 1 abortion. The specificities of the FAT on fetal tissues and mare's placenta and of the MAT on fetal fluid were 100%. The sensitivity of the FAT was 98.7%, and that of the MAT was 81.3%.

Seroprevalence to Leptospira interrogans serovar hardjo in Merino stud rams in South Australia

A serological survey of 2160 Merino stud rams on 36 farms detected positive reactions greater than or equal to 1/100 in 42% of animals using the microscopic agglutination test (MAT) to Leptospira interrogans serovar hardjo. Twenty flocks had seroprevalence values greater than 30% with 15 flocks having values > or = 60%. The enzyme-linked immunosorbent assays showed that 47% and 3% of rams on the 36 farms were positive for IgG and IgM antibodies, respectively. Forty-five percent of hardjo reactions were in rams that had not been exposed to cattle. Significant correlations were found between IgM reactors and creek/dam water pumped into troughs, and between MAT/IgG reactors and total flock size. No statistical relationships were detected between positive reactors and two different annual average rainfall gradients, the time of the year in which samples were obtained, or agricultural regions of South Australia. Infections with an organism of the Sejroe serogroup is widespread in Merino stud rams.

Survey on the prevalence of leptospira infections in the Italian population.

This investigation is the first nationwide survey on the circulation of leptospira infections in human beings in Italy. In nine out of twenty Italian regions, representative samples of the population were investigated for the presence of leptospira infections. Unexpectedly, leptospira infections were found to be widespread, the number of cases being much higher than the diagnosed clinical cases. There were found to be high, medium, and low risk areas. On the whole, the risk for the rural population was no higher than the risk for urban dwellers; leisure activities, contact with animals and residence on the plain versus residence in the hills were important risk factors. There was an unidentified risk factor in urbanites which was absent in the rural population. A changing pattern in infecting serovars was observed, with infections from serogroups Sejroe, Javanica and Australis prevailing over infections from the Icterohaemorrhagiae and Bataviae serogroups, which were the main agents of human leptospirosis during the 1950s. The mechanisms of these changes, the need for epidemiological surveys and improved diagnostic methods of screening are discussed.

Development of a control strategy for Leptospira hardjo infection in a closed beef herd.

Serological evidence of infection with a leptospire belonging to the Sejroe serogroup was identified in a closed population of Luing cattle in the west of Scotland, and the geographical isolation of the population presented an opportunity to control and possibly eradicate the infection in a large beef herd farmed under extensive conditions. Serological and bacteriological studies revealed that infection was present at a high level throughout the herd, and that the infecting serovar was hardjo. Unlike endemic hardjo infection in dairy herds, new infections were still occurring in older age-groups. Investigations of other domestic and free-living species sharing the habitat demonstrated that the maintenance of an endemic focus of hardjo was restricted to the cattle. Changes in management to prevent the transmission of infection to successive cohorts of young animals were impractical and risky, and antibiotic treatment followed by removal to clean pasture failed to prevent new cases. Thus vaccination offered the only means of control and possible eradication, and the epidemiological characteristics of the infection dictated that the programme be applied to the whole herd.

Isolation of Leptospira interrogans from kidneys of Zimbabwe beef cattle.

Four hundred and eighty bovine kidneys were collected from an abattoir near Harare between December 1987 and November 1988, and leptospires were recovered from 50 (10.4 per cent) of them. The isolates were identified to serogroup level by the microscopic agglutination test; 32 belonged to serogroup Sejroe, seven were Pyogenes, four Hebdomadis, two Tarassovi, and one isolate each belonged to serogroups Australis, Bataviae, Grippotyphosa, Icterohaemorrhagiae and Pomona.

Characterization of serovars of the genus Leptospira by DNA hybridization with hardjobovis and icterohaemorrhagiae recombinant probes with special attention to serogroup sejroe

Recombinant DNA probes derived from genomic libraries of serovars hardjobovis and icterohaemorrhagiae were applied for the characterization of leptospires. Differences in hybridization signals in combination with the banding pattern appear to provide good characteristics for strain typing. The banding patterns were easy to distinguish, since the recombinant DNA probes hybridized with a limited number of fragments. They were also indicative of genomic relationships between serovars. The probes suggested the existence of four subgroups with extensive genomic homology within the serogroup Sejroe. A number of serovars outside the serogroup Sejroe showed genomic homology with these subgroups. Amplification with the polymerase chain reaction showed a correlation with the genomic homologies demonstrated by Southern analysis. Knowledge about genomic relationships between leptospiral strains, as revealed by Southern analysis, may lead to a more rational approach for primer selection for polymerase chain reaction or cloning of particular genes.

NOTES: Leptospira interrogans Serovar Unipertama Isolated in Malaysia

A leptospiral isolate from a bovine kidney was found to be antigenically different from all previously recognized serovars of Leptospira interrogans based on the cross-agglutinin absorption test. The new serovar belongs to the Sejroe serogroup, and the name Leptospira interrogans serovar unipertama is proposed for it, with strain K2-1 as the reference strain.

Recent trends in human leptospirosis in Italy.

The recent epidemiological trends of human leptospirosis in Italy were investigated using data collected for the years 1981-1985. A total of 626 hospitalized patients with clinical diagnoses of suspected leptospirosis were reported by hospital centers from several Italian regions. Epidemiological, clinical and seroimmunological data were collected in 517 of these cases and examined by the National Center for Leptospirosis. Serological findings in 33.5% of these subjects met the criteria for confirmation of the disease. In 21.8% of the subjects, low titer antibodies were detected, which possibly reflected previous leptospiral infections. An early antibiotic treatment of the current infection may also have lowered the seroimmunological response in some of these patients. In 59.3% of the confirmed cases, modes of transmission were allotted equally between accidental events and recreational or occupational activities. Drinking water from an open air fountain emerged as an uncommon mode of transmission; it was responsible for an outbreak of 33 cases of leptospirosis. In another 37.07% of the subjects, it was impossible to establish the mode of transmission. Respiratory or influenza-like symptoms were the only clinical signs of illness in 21.2% of the patients with confirmed leptospirosis. In comparison to the sixties and seventies, the prevalence of infecting serovars showed increasing incidence of infections due to serovars of the Javanica (11.0%) and Australis (11.0%) serogroups and an important decrease in the Bataviae serogroup infections (from 58.8% in rice-field workers in the forties to 0.6% in the years 1981-1985). Sejroe serogroup infections accounted for 4.5 per cent of confirmed cases of leptospirosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Genetic and antigenic differences of serologically indistinguishable leptospires of serovar hardjo

Pathogenic leptospires of serovar hardjo isolated from North American cattle were compared genetically and antigenically to reference strain hardjoprajitno of the Sejroe serogroup. Guanine-plus-cytosine (G+C) contents were determined for the genomes, and microscopic agglutination, Western blotting (immunoblotting), and immunoprecipitation were used to characterize antigenic relatedness. Major differences were demonstrated between the isolates and the reference strain. The G+C content of the reference strain was calculated to be approximately 34 +/- 1%, and those of the isolates were calculated at 39 +/- 1%. Antigenic differences between the isolates and the reference strain were identified by using rabbit immune serum raised against a hardjo isolate exhaustively adsorbed with hardjoprajitno whole and sonicated cells. Western blot analysis and immunoprecipitation using this adsorbed serum revealed antigens apparently unique for the hardjo isolates. Microscopic agglutination with the adsorbed rabbit serum did not agglutinate hardjoprajitno when diluted 1:2 but agglutinated bovine isolates to a 1:32 dilution. Bovine antiserum raised against the isolates was also used to identify antigens by immunoprecipitation.

Serological prevalence of leptospiral infection in domestic animals in West Malaysia

A cross-sectional serological survey of domestic animals in West Malaysia revealed that 25.5% of the animals examined had agglutinating antibodies to one or more antigens belonging to Leptospira interrogans. Significant prevalence of infection was observed in cattle (40.5%), buffaloes (31%) and pigs (16%). The Sejroe serogroup was shown to be the principal one involved in cattle and buffaloes, and to a lesser extent the Tarassovi and Pomona serogroups. Evidence of infection in domestic animals by strains bearing the other seven antigens appeared insignificant and was indicative of sporadic infection. A majority of the large (semi-intensive) cattle and buffalo farms demonstrated a high prevalence of leptospiral infection. In both species of domestic animals mentioned above, the prevalence of infection was significantly higher (P = 0.01) in the semi-intensive farms than in the smallholdings. Amongst cattle, the droughtmasters had the highest prevalence whilst the Kedah-Kelantan (an indigenous breed) had the lowest prevalence of leptospiral infection. In general, the temperate breeds of cattle had a significantly (P = 0.01) higher prevalence of infection than local breeds. Leptospiral infection in goats and sheep was shown to be sporadic, and the Pomona serogroup was the principal leptospiral serogroup involved in these small ruminants. The prevalence of infection in pigs was observed to decline during the study period, and it is suspected that pigs in West Malaysia are the maintenance host for serovar pomona whilst cattle are the maintenance host for serovar hardjo. Overall, it appears that domestic animals in Malaysia will play a bigger role in the epidemiology of leptospiral infection with the advent of sophisticated farming.

Serological studies on British isolates of the Sejroe serogroup of leptospira. II. An evaluation of the factor analysis method of identifying leptospires using strains belonging to the Sejroe serogroup.

Twelve British isolates of leptospira belonging to the Sejroe serogroup were examined using a series of six factor sera prepared by a number of different absorption methods. Ten of the isolates were identified as Leptospira interrogans serovar hardjo and two as L. interrogans serovar saxkoebing. These isolates had previously been identified using the cross agglutination absorption method.

Serological studies of British leptospiral isolates of the Sejroe serogroup. III. The distribution of leptospires of the Sejroe serogroup in the British Isles.

Some 94 strains of leptospires belonging to the Sejroe serogroup isolated in the British Isles were identified to the serovar level using specific factor sera. Seventy strains were identified as Leptospira interrogans serovar hardjo, 66 from cattle, 2 from pigs and 1 each from a sheep foetus and a human. Twenty-four strains were identified as L. interrogans serovar saxkoebing, most strains were isolated from either wood mice, bank or field voles but strains were also isolated from badgers, a fox and a dog.

Serological studies on British leptospiral isolates of the Sejroe serogroup. I. The identification of British isolates of the Sejroe serogroup by the cross agglutinin absorption test.

Using the cross agglutinin absorption test 12 British leptospiral isolates of the Sejroe serogroup were identified to serovar level. Six strains isolated from cattle, two from pigs and one from a human were identified as Leptospira interrogans serovar hardjo. Two isolates from wildlife were identified as Leptospira interrogans serovar saxkoebing. One further strain isolated from wildlife closely resembled serovar saxkoebing, but specific identification was not possible. These are the first reported isolations of serovar saxkoebing in the United Kingdom. The problems associated with the cross agglutinin absorption test, and possible alternative typing procedures are discussed.

Leptospiral agglutinins among cattle in the Republic of Guyana.

Cattle sera collected in the Republic of Guyana during 1981 to 1982 were examined for serologic evidence of leptospirosis. Significant leptospiral agglutinins (1:100 or higher) were disclosed in 49.1% of 2,935 apparently normal cattle from 734 farms in the three major cattle-raising regions of the country. Seroreactions principally involved hardjo and wolffi of the Sejroe serogroup, icterohaemorrhagiae, pomona, tarassovi, canicola and grippotyphosa. A high proportion of reactions to one or more of different leptospiral serovars were observed in each of the three regions. These variations were attributed to differences in environmental conditions and farming practices. The findings provided evidence for the first time of the widespread occurrence of leptospirosis in cattle in Guyana caused by multiple leptospiral serovars.

Serological studies on leptospirosis in livestock and chickens from Grenada and Trinidad

Sera from 1,206 livestock animals and chickens on Grenada and Trinidad were tested for leptospiral antibodies by the microscopic agglutination test. 376 of the sera were positive (25% of those tested on Grenada and 44% on Trinidad). The positive sera were obtained from 25% of 324 cattle, 35% of 130 pigs, 35% of 146 sheep, 25% of 44 goats and 11% of 175 chickens on Grenada; and 92% of 26 cattle, 53% of 122 pigs, 76% of 87 horses and donkeys and 11% of 144 chickens on Trinidad. Eight sera from ducks and geese on Trinidad were tested and found to be negative. The serogroups most commonly found to react with the sera of the Grenadian animals were Autumnalis, Icterohaemorrhagiae, Hebdomadis and the related serogroups Sejroe and Mini, and Pyrogenes; in the Trinidadian animals they were Icterohaemorrhagiae, Autumnalis, Hebdomadis and its related serogroups, and Panama. Strains of serogroup Pomona do not appear to have become established as livestock pathogens on the islands.

Kidney disease of sheep, associated with infection by leptospires of the Sejroe serogroup.

Kidney disease of sheep, associated with infection by leptospires of the Sejroe serogroup.

Six new leptospiral serovars isolated from wild animals in Peru.

Six new serovars of Leptospira interrogans were isolated from opossums (Didelphis marsupialis and Philander opossum) trapped in the Peruvian jungle. The proposed names, type strain designation, and serogroup of the serovars, respectively, were: huallaga, strain M-7, Djasiman serogroup; luis, strain M-6, Tarassovi serogroup; machiguenga, strain MMD-3, Icterohaemorrhagiae serogroup; rioja, strain MR-12, Bataviae serogroup; rupa rupa, strain M-3, Sejroe serogroup; and tingomaria, strain M-13, Cynopteri serogroup.

Laboratory diagnosis of bovine abortion caused by various species of bacteria

Bovine leptospirosis is often associated with host-adapted leptospires infections, such as strains belonging to the Sejroe serogroup. Although bovine leptospirosis by adapted strains may result in abortions, fetal death, premature births and the birth of weak and/or low-weight calves, this infection is more closely associated with subtler syndromes, such as subfertility and early embryonic death. In this way, this silent disease can go unnoticed and undiagnosed, compromising reproductive efficiency with a consequent decrease in the productivity of herds over long periods. For many years, genital tract infection has been considered a secondary effect of renal infection with the assumption being that leptospires are found in the genital tract due to bacteremia caused by renal colonization. In contrast to this hypothesis, there is some evidence in the literature that suggests that genital leptospirosis should be considered a specific syndrome dissociated from renal/systemic disease. Therefore, this paper aims to gather and critically analyze information about genital leptospirosis in cattle, considering the disease a distinct syndrome, herein denominated bovine genital leptospirosis (BGL), that requires a unique approach to diagnosis and treatment.