The El Niño–Southern Oscillation (ENSO)–pandemic Influenza connection: Coincident or causal?

Shaman, Jeffrey; Lipsitch, Marc

doi:10.1073/pnas.1107485109

Cited by 36 publications

(26 citation statements)

References 29 publications

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“…, Vandegrift et al. , Kilpatrick , Shaman and Lipsitch ). Indeed, emerging infectious diseases of humans are strongly associated with mammals that utilize human‐modified environments (McFarlane et al.…”

Section: Discussionmentioning

confidence: 99%

“…Such events can have devastating impacts on wildlife; for example, canine distemper virus infection of African carnivores, and feline leukemia virus outbreaks in Iberian lynx and Florida panther have resulted in high morbidity and mortality in these threatened carnivores (Roelke-Parker et al 1996, Cleaveland et al 2000, Brown et al 2008, Meli et al 2009). Conversely, wildlife species are reservoirs of many diseases of domestic animals and humans, including West Nile virus, Ebola, and influenza (Leroy et al 2005, Vandegrift et al 2010, Kilpatrick 2011, Shaman and Lipsitch 2013. Indeed, emerging infectious diseases of humans are strongly associated with mammals that utilize human-modified environments (McFarlane et al 2012).…”

Section: Proximity To the Wildland-urban Interface And Pathogen Exposurementioning

confidence: 99%

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Pathogen exposure varies widely among sympatric populations of wild and domestic felids across the United States

Carver

Bevins

Lappin

et al. 2016

Ecological Applications

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Abstract. Understanding how landscape, host, and pathogen traits contribute to disease exposure requires systematic evaluations of pathogens within and among host species and geographic regions. The relative importance of these attributes is critical for management of wildlife and mitigating domestic animal and human disease, particularly given rapid ecological changes, such as urbanization. We screened >1000 samples from sympatric populations of puma (Puma concolor), bobcat (Lynx rufus), and domestic cat (Felis catus) across urban gradients in six sites, representing three regions, in North America for exposure to a representative suite of bacterial, protozoal, and viral pathogens (Bartonella sp., Toxoplasma gondii, feline herpesvirus-1, feline panleukopenea virus, feline calicivirus, and feline immunodeficiency virus). We evaluated prevalence within each species, and examined host trait and land cover determinants of exposure; providing an unprecedented analysis of factors relating to potential for infections in domesticated and wild felids. Prevalence differed among host species (highest for puma and lowest for domestic cat) and was greater for indirectly transmitted pathogens. Sex was inconsistently predictive of exposure to directly transmitted pathogens only, and age infrequently predictive of both direct and indirectly transmitted pathogens. Determinants of pathogen exposure were widely divergent between the wild felid species. For puma, suburban land use predicted increased exposure to Bartonella sp. in southern California, and FHV-1 exposure increased near urban edges in Florida. This may suggest interspecific transmission with domestic cats via flea vectors (California) and direct contact (Florida) around urban boundaries. Bobcats captured near urban areas had increased exposure to T. gondii in Florida, suggesting an urban source of prey. Bobcats captured near urban areas in Colorado and Florida had higher FIV exposure, possibly suggesting increased intraspecific interactions through pile-up of home ranges. Beyond these regional and pathogen specific relationships, proximity to the wildland-urban interface did not generally increase the probability of disease exposure in wild or domestic felids, emphasizing the importance of local ecological determinants. Indeed, pathogen exposure was often negatively associated with the wildland-urban interface for all felids. Our analyses suggest cross-species pathogen transmission events around this interface may be infrequent, but followed by self-sustaining propagation within the new host species.

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Section: Discussionmentioning

confidence: 99%

Section: Proximity To the Wildland-urban Interface And Pathogen Exposurementioning

confidence: 99%

Pathogen exposure varies widely among sympatric populations of wild and domestic felids across the United States

Carver

Bevins

Lappin

et al. 2016

Ecological Applications

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“…Influenza activity reaches its peak earlier during the years when ENSO occurs . Specifically, all eight confirmed influenza pandemics since 1580 have occurred after a moderate to strong El Niño event , and the most recent of these confirmed pandemics (1918, 1957, 1968 and 2009) have occurred a few months after a La Niña event . Increased contact among various species during an ENSO may greatly accelerate genetic recombination of any circulating influenza viruses, and certain strains of the virus can be transferred from animal hosts to humans under the influence of environmental fluctuations related to sunspots and cosmic rays, thereby triggering an influenza pandemic.…”

Section: Resultsmentioning

confidence: 99%

Is sunspot activity a factor in influenza pandemics?

2016

Reviews in Medical Virology

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Extremes of sunspot activity to within plus or minus 1 year may precipitate influenza pandemics. Mechanisms of epidemic initiation and early spread are discussed including primary causation by externally derived viral variants (from space via cometary dust). Efforts to construct a comprehensive early warning system for potential influenza and other viral pandemics that include analysis of sunspot activity and stratospheric sampling for viral variants should be supported. Copyright © 2016 John Wiley & Sons, Ltd.

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“…Although El Niño, the warm phase of ENSO, has been associated with influenza pandemics ( 17 ), and with seasonal influenza epidemics in Japan ( 18 ), time series of ENSO have not been shown to have spectra coherence with influenza-like illness in the northern and southern hemispheres, where seasonality of influenza occurrence is strongest. The putative association of La Niña, the cool phase of ENSO with seasonal influenza epidemics ( 19 ), strengthens the need for time-varying spectral analysis. This study was done to determine if seasonality, timing of peak, and severity of influenza epidemics are coupled to phases of ENSO.…”

Section: Introductionmentioning

confidence: 99%

Seasonal Influenza Epidemics and El Niños

Oluwole

2015

Front. Public Health

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Seasonal influenza epidemics occur annually during the winter in the northern and southern hemispheres, but timing of peaks and severity vary seasonally. Low humidity, which enhances survival and transmission of influenza virus, is the major risk factor. Both El Niño and La Niña phases of El Niño-southern oscillation (ENSO), which determine inter-annual variation of precipitation, are putative risk factors. This study was done to determine if seasonality, timing of peak, and severity of influenza epidemics are coupled to phases of ENSO. Monthly time series of positive specimens for influenza viruses and of multivariate El Niño-Southern Oscillation Index from January 2000 to August 2015 were analyzed. Seasonality, wavelet spectra, and cross-wavelet spectra analyses were performed. Of 31 countries in the dataset, 21 were in the northern hemisphere and 10 in the southern hemisphere. The highest number of influenza cases occurred in January in the northern hemisphere, but in July in the southern hemisphere, p < 0.0001. Seasonal influenza epidemic was coupled to El Niño, while low occurrence was coupled to La Niña. The moderate La Niña of 2010–2011 was followed by weak seasonal influenza epidemic. The influenza pandemic of 2009–2010 followed the moderate El Niño of 2009–2010, which had three peaks. Spectrograms showed time-varying periodicities of 6–48 months for ENSO, 6–24 months for influenza in the northern hemisphere, and 6–12 months for influenza in the southern hemisphere. Cross spectrograms showed time-varying periodicities at 6–36 months for ENSO and influenza in both hemispheres, p < 0.0001. Phase plots showed that influenza time series lagged ENSO in both hemispheres. Severity of seasonal influenza increases during El Niño, but decreases during La Niña. Coupling of seasonality, timing, and severity of influenza epidemics to the strength and waveform of ENSO indicate that forecast models of El Niño should be integrated into surveillance programs for influenza epidemics.

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The El Niño–Southern Oscillation (ENSO)–pandemic Influenza connection: Coincident or causal?

Cited by 36 publications

References 29 publications

Pathogen exposure varies widely among sympatric populations of wild and domestic felids across the United States

Pathogen exposure varies widely among sympatric populations of wild and domestic felids across the United States

Is sunspot activity a factor in influenza pandemics?

Seasonal Influenza Epidemics and El Niños

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