<i>Leptospira autumnalis</i>isolated from a human case from Avadi, India, and the serovar's predominance in local rat and bandicoot populations

Saravanan, R.; Rajendran, P.; Thyagarajan, S P; Smythe, Lee D.; Norris, Michelle A.; Symonds, Meegan L.; Dohnt, Michael F.

doi:10.1080/00034983.2000.11813569

Cited by 12 publications

(8 citation statements)

References 4 publications

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“…The cell monolayers were washed three times with autoclaved PBS and then infected with each of the suspensions at an MOI of 100 (100 leptospires per cell) for 10, 20, 30, 40, 50 and 60 min, respectively. After infection, the coverslips were washed three times with PBS to remove non-adherent leptospires, fixed in 5% formaldehyde, stained with silver nitrate, and observed under a light microscope [59]. The adhesion ratio was defined as the number of adhering leptospires per 100 infected host-cells × 100% [11].…”

Section: Methodsmentioning

confidence: 99%

Inactivation of the fliY gene encoding a flagellar motor switch protein attenuates mobility and virulence of Leptospira interrogansstrain Lai

et al. 2009

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BackgroundPathogenic Leptospira species cause leptospirosis, a zoonotic disease of global importance. The spirochete displays active rotative mobility which may contribute to invasion and diffusion of the pathogen in hosts. FliY is a flagellar motor switch protein that controls flagellar motor direction in other microbes, but its role in Leptospira, and paricularly in pathogenicity remains unknown.ResultsA suicide plasmid for the fliY gene of Leptospira interrogans serogroup Icterohaemorrhagiae serovar Lai strain Lai that was disrupted by inserting the ampicillin resistance gene (bla) was constructed, and the inactivation of fliY gene in a mutant (fliY-) was confirmed by PCR and Western Blot analysis. The inactivation resulted in the mRNA absence of fliP and fliQ genes which are located downstream of the fliY gene in the same operon. The mutant displayed visibly weakened rotative motion in liquid medium and its migration on semisolid medium was also markedly attenuated compared to the wild-type strain. Compared to the wild-type strain, the mutant showed much lower levels of adhesion to murine macrophages and apoptosis-inducing ability, and its lethality to guinea pigs was also significantly decreased.ConclusionInactivation of fliY, by the method used in this paper, clearly had polar effects on downstream genes. The phentotypes observed, including lower pathogenicity, could be a consequence of fliY inactivation, but also a consequence of the polar effects.

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Section: Methodsmentioning

confidence: 99%

Inactivation of the fliY gene encoding a flagellar motor switch protein attenuates mobility and virulence of Leptospira interrogansstrain Lai

et al. 2009

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“…A multiple logistic regression analysis with environmental and biological factors as independent variables and leptospiral infection as dependant variable identifi ed male Mus domesticus, sexually active and living in humid biotopes 500 m above the sea level as the most likely reservoir. Rats and bandicoots have shown evidence of anti-leptospiral antibodies following isolation of leptospires from suspected human patient from the suburbs of Chennai (Saravanan et al 2000). Elsewhere, in Tamil Nadu anti-leptospiral antibodies (52.1%) were evident from the fi eld rodents (Natarajaseenivasan et al 2002).…”

Section: Rodentsmentioning

confidence: 99%

Leptospirosis: an emerging global public health problem

2008

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Leptospirosis has been recognized as an emerging global public health problem because of its increasing incidence in both developing and developed countries.A number of leptospirosis outbreaks have occurred in the past few years in various places such as Nicaragua, Brazil and India.Some of these resulted due to natural calamities such as cyclone and floods. It is a direct zoonotic disease caused by spirochetes belonging to different pathogenic species of the genus Leptospira. Large number of animals acts as carriers or vectors.Human infection results from accidental contact with carrier animals or environment contaminated with leptospires. The primary source of leptospires is the excretor animal, from whose renal tubules leptospires are excreted into the environment with the animal urine. Majority of leptospiral infections are either sub clinical or result in very mild illness and recover without any complications.However,a small proportion develops various complications due to involvement of multiple organ systems. In such patients, the clinical presentation depends upon the predominant organs involved and the case fatality ratio could be about 40% or more. Febrile illness with icterus, splenomegaly and nephritis (known as Weil's disease), acute febrile illness with severe muscle pain,febrile illness with pulmonary haemorrhages in the form of haemoptysis, jaundice with pulmonary haemorrhages, jaundice with heamaturea, meningitis with haemorrhages including sub conjunctival haemorrhage or febrile illness with cardiac arrhythmias with or without haemorrhages are some of the syndromes. Because of the protean manifestations of leptospirosis it is often misdiagnosed and under-reported. Although the basic principles of prevention such as source reduction,environmental sanitation, more hygienic work-related and personal practices etc., are same everywhere, there is no universal control method applicable to all epidemiological settings. Comprehensive understanding of the eco-epidemiological and cultural characteristics of a community that faces the problem of leptospirosis is an essential prerequisite for evolving an effective and acceptable control measure.

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“…Research from 2003 conducted on the Andaman Islands showed a seroprevalence of 7.1% in R. rattus (n = 85) (Sharma, Vijayachari, Sugunan, & Sehgal, 2003), which again is in line with our findings (7.9%). Research on rodents from a suburban area in India showed 14.3% of the trapped R. rattus (n = 28), and 16.1% of the B. bengalensis (n = 58) were serological positive for Leptospira (Saravanan et al, 2000). The findings specifically on R. rattus infections in India by Saravanan et al were higher than the 7.9% found in the R. rattus (n = 191) from the current study in Bangladesh.…”

Section: Discussioncontrasting

confidence: 74%

“…These findings are in line with the fact that Leptospira species, borgpetersenii and interrogans, contribute a great deal to human disease in Asia (Benacer et al, 2013;Cosson et al, 2014;Laras et al, 2002;Thaipadungpanit et al, 2007). Also, in Europe, L. borgpetersenii and L. interrogans are the most observed Leptospira genomospecies present in rodents; however, in Europe, a third genomospecies is Chapter 4 (Saravanan et al, 2000) Bandicota indica 4% (n = 75)…”

Section: Discussionsupporting

confidence: 61%

“…Previous studies in Asia on rodents identify R. rattus to be the main reservoir host for human pathogenic Leptospira (Johnson et al, 2004;Ko et al, 1999;Sarkar et al, 2002). Other studies from Asia show varying numbers of infection percentages, ranging from 7.1%-22% Ivanova et al, 2012;Koma et al, 2013;Saravanan et al, 2000;Sharma et al, 2003).…”

Section: Leptospira Spp Prevalence In Wild Small Mammalsmentioning

confidence: 93%

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Rodent-borne health risks in farming systems

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Leptospira autumnalisisolated from a human case from Avadi, India, and the serovar's predominance in local rat and bandicoot populations

Cited by 12 publications

References 4 publications

Inactivation of the fliY gene encoding a flagellar motor switch protein attenuates mobility and virulence of Leptospira interrogansstrain Lai

Inactivation of the fliY gene encoding a flagellar motor switch protein attenuates mobility and virulence of Leptospira interrogansstrain Lai

Leptospirosis: an emerging global public health problem

Rodent-borne health risks in farming systems

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