Asymptomatic and chronic carriage of Leptospira interrogans serovar Pomona in California sea lions (Zalophus californianus)

Prager, Katherine C.; Greig, Denise J.; Alt, David P.; Galloway, Renee L.; Hornsby, Richard L.; Palmer, Lauren; Soper, Jennifer L.; Wu, Qingzhong; Zuerner, Richard L.; Gulland, Frances M. D.; Lloyd‐Smith, James O.

doi:10.1016/j.vetmic.2013.01.032

Cited by 36 publications

(45 citation statements)

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“…Periodic epizootics occur every 3-5 years and result in large numbers of CSLs stranding with clinical leptospirosis (Gulland et al, 1996b;Lloyd-Smith et al, 2007). An asymptomatic, chronic carrier state may provide a mechanism for persistence of the bacterium in the population (Prager et al, 2013). Though cases in freeranging CSLs can occur throughout the year they are most commonly noted between July and December (Gulland et al, 1996b).…”

Section: Bacteriamentioning

confidence: 99%

Pinnipediae

Colegrove

Burek‐Huntington²,

Roe

et al. 2018

Pathology of Wildlife and Zoo Animals

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Section: Bacteriamentioning

confidence: 99%

Pinnipediae

Colegrove

Burek‐Huntington²,

Roe

et al. 2018

Pathology of Wildlife and Zoo Animals

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“…Wild captures of apparently healthy California sea lions during a leptospirosis outbreak revealed that 39% of individuals were asymptomatic shedders, suggesting the possibility of relatively common chronic shedding (Prager et al . ). However, surveys to detect changes in the proportions of symptomatic and asymptomatic shedders across seasons are needed to understand how fluctuations in the prevalence of chronic shedding impact persistence.…”

Section: Discussionmentioning

confidence: 97%

“…We assumed that chronic shedders suffered no disease‐induced mortality, in line with current understanding of leptospirosis in other maintenance hosts (Ellis ) and the observation of asymptomatic shedders amongst both wild‐caught and stranded sea lions (Prager et al . , ). We assumed that immunity against the same serovar was lifelong (Adler & de la Peña Moctezuma ; Evangelista & Coburn ).…”

Section: Methodsmentioning

confidence: 99%

“…; Prager et al . , ). With asymptomatic shedders, a long history of disease surveillance, and seasonality in both transmission and susceptible recruitment, the sea lion/leptospirosis system provides a unique opportunity to assess chronic shedding as a mechanism of pathogen persistence in wildlife, and to highlight challenges researchers may face conducting similar assessments in other systems.…”

Section: Introductionmentioning

confidence: 99%

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Detecting signals of chronic shedding to explain pathogen persistence:Leptospira interrogansinCalifornia sea lions

Buhnerkempe

Prager

Strelioff

et al. 2017

Journal of Animal Ecology

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Identifying mechanisms driving pathogen persistence is a vital component of wildlife disease ecology and control. Asymptomatic, chronically infected individuals are an oft-cited potential reservoir of infection, but demonstrations of the importance of chronic shedding to pathogen persistence at the population-level remain scarce. Studying chronic shedding using commonly collected disease data is hampered by numerous challenges, including short-term surveillance that focuses on single epidemics and acutely ill individuals, the subtle dynamical influence of chronic shedding relative to more obvious epidemic drivers, and poor ability to differentiate between the effects of population prevalence of chronic shedding vs. intensity and duration of chronic shedding in individuals. We use chronic shedding of Leptospira interrogans serovar Pomona in California sea lions (Zalophus californianus) as a case study to illustrate how these challenges can be addressed. Using leptospirosis-induced strands as a measure of disease incidence, we fit models with and without chronic shedding, and with different seasonal drivers, to determine the time-scale over which chronic shedding is detectable and the interactions between chronic shedding and seasonal drivers needed to explain persistence and outbreak patterns. Chronic shedding can enable persistence of L. interrogans within the sea lion population. However, the importance of chronic shedding was only apparent when surveillance data included at least two outbreaks and the intervening inter-epidemic trough during which fadeout of transmission was most likely. Seasonal transmission, as opposed to seasonal recruitment of susceptibles, was the dominant driver of seasonality in this system, and both seasonal factors had limited impact on long-term pathogen persistence. We show that the temporal extent of surveillance data can have a dramatic impact on inferences about population processes, where the failure to identify both short- and long-term ecological drivers can have cascading impacts on understanding higher order ecological phenomena, such as pathogen persistence.

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“…In Europe, within the Pomona serogroup, serovars Pomona and Mozdok in pigs and rodent reservoirs, respectively, are the most commonly encountered members of this group, with occasional spill-over into non-reservoir species. Expansion of reservoir species has been reported for serovar Pomona, including its ability to infect sea lions and also cause disease in this species (Prager and others 2013). …”

mentioning

confidence: 99%

Adding a further twist to the tail of leptospirosis in the UK

Cutler

2017

Veterinary Record

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CONVENTIONAL serological typing of the spirochaete Leptospira (Fig 1) is challenging, particularly when applied to serogroup Pomona. This group being comprised of members of four genospecies, namely Leptospira interogans (Kennewicki; Monjakov; Pomona), Leptospira kirschneri (Altodouro; Mazdok; Tsaratsova; Kumming), Leptospira noguchii and Leptospira sanarosai; the last two species not being endemic to Europe. The significance attributed to these strains is hugely variable, with L kirschneri seorvar Mozdock rarely resulting in clinical signs of infection among livestock or companion animals, whereas L interrogans serovars Pomona type Kennewicki potentially results in devastating consequences from infection (Timoney and others 2011).

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Asymptomatic and chronic carriage of Leptospira interrogans serovar Pomona in California sea lions (Zalophus californianus)

Cited by 36 publications

References 20 publications

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Detecting signals of chronic shedding to explain pathogen persistence:Leptospira interrogansinCalifornia sea lions

Adding a further twist to the tail of leptospirosis in the UK

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