Urban informal settlements as hotspots of antimicrobial resistance and the need to curb environmental transmission. Maya L. Nadimpalli, Sara J. Marks, Maria Camila Montealegre, Robert H. Gilman, Monica J. Pajuelo, Mayuko Saito, Pablo Tsukayama, Sammy M. Njenga, John Kiiru, Jenna Swarthout, Mohammad Aminul Islam, Timothy R. Julian & Amy J. Pickering; Nature Microbiology volume 5, pages787–795(2020)
Predators and Vectors
Predators, such as bats and aerial-feeding birds, can eat disease vectors, such as mosquitoes, and also other insects. They can also eat predators (such as dragonflies) of insects.
The relationship of Purple Martins to mosquito control. Herbert W. Kale II. The Auk 85: 654-661 1968.
Click to access p0654-p0661.pdf
Incidence and taxonomic richness of mosquitoes in the diets of little brown and big brown bats. Amy K Wray, Michelle A Jusino, Mark T Banik, Jonathan M Palmer, Heather Kaarakka, J Paul White, Daniel L Lindner, Claudio Gratton, M Zachariah Peery
Journal of Mammalogy, Volume 99, Issue 3, 1 June 2018, Pages 668–674
https://academic.oup.com/jmammal/article/99/3/668/4993282
The may also eat nuisance insects.
Are invasive fire ants kept in check by native aerial insectivores? Jackson A. Helms, Aaron P. Godfrey, Tayna Amesand Eli S. Bridge. Biology Letter: Volume 12; Issue 5
https://royalsocietypublishing.org/doi/full/10.1098/rsbl.2016.0059
Predators can affect other public health issues, as well:
https://blog.nature.org/science/2018/03/08/urban-leopards-can-save-lives-by-eating-feral-dogs/
And perhaps avian reservoirs:
Seasons of disease
Infectious disease rates rise and fall through out the year – that is, flu season is real.
Influenza-associated mortality determined from all-cause mortality, Denmark 2010/11-2016/17: The FluMOMO model.Influenza Other Respir Viruses. 2018 Sep;12(5):591-604. doi: 10.1111/irv.12564. Epub 2018 May 6. Nielsen J, Krause TG, Mølbak K.
https://www.ncbi.nlm.nih.gov/pubmed/29660769
This occurs for diseases other than flu, and can be related to environmental factors.
Rapid Expert Consultation on SARS-CoV-2 Survival in Relation to Temperature and Humidity and Potential for Seasonality for the COVID-19 Pandemic (April 7, 2020)
(2020)
Cats and Dogs
Companion animals have demographics and behaviors, too – what they do, and their ages, and other factors can influence the probability that they will have, and potentially pass on, infectious diseases.
They can be mechanical vectors (or biological vectors) with their fur harboring bacterial loads.
For examples –
Young, male cats are more likely to be associated with Cat Scratch Disease (Bartonella)
Cat Scratch Disease in Connecticut — Epidemiology, Risk Factors, and Evaluation of a New Diagnostic Test. Kenneth M. Zangwill, Douglas H. Hamilton, Bradley A. Perkins, Russell L. Regnery, Brian D. Plikaytis, James L. Hadler, Matthew L. Cartter, and Jay D. Wenger. July 1, 1993; N Engl J Med 1993; 329:8-13; DOI: 10.1056/NEJM199307013290102
https://www.nejm.org/doi/full/10.1056/NEJM199307013290102
Dog fur can have ample communities of pathogens (though perhaps less than in mens’ beards)
Would it be safe to have a dog in the MRI scanner before your own examination? A multicenter study to establish hygiene facts related to dogs and men. Gutzeit A, Steffen F, Gutzeit J, Gutzeit J, Kos S, Pfister S, Berlinger L, Anderegg M, Reischauer C, Funke I, Froehlich JM, Koh DM, Orasch C. Eur Radiol. 2019 Feb;29(2):527-534. doi: 10.1007/s00330-018-5648-z. Epub 2018 Jul 30.
https://www.ncbi.nlm.nih.gov/pubmed/30062526
Outdoor infections
Environmentally acquired infections can be dangerous, and they can be acquired via multiple routes, and their risks can be mitigated –
https://sportsmedicine-open.springeropen.com/articles/10.1186/s40798-019-0208-x
Infection from Outdoor Sporting Events—More Risk than We Think? Jamie E. DeNizio & David A. Hewitt; Sports Medicine – Open volume 5, Article number: 37 (2019)
Of dogs and men
Who (and where) would you expect to have more human-pathogenic micro-organisms: a man in his beard, or a dog in its fur?
https://www.ncbi.nlm.nih.gov/pubmed/30062526
What is community size with respect to infectious disease?
It has been known since the 1950s that when a community’s size is below a certain threshold, measles does not persist consistently through time, it will have “fade-outs” – Bartlett looked at this in the U.S. and England, and found that threshold to be in the range of 250,000 to 300,000. That, however, does not refer to population density (which is what we would use in ecology when looking at density dependent effects), but total population of the given community, e.g., New York City, or Akron, or Philadelphia.
Given that members of these communities are centered around a city, for work, for leisure, for administrative needs (e.g, voter registration, or DMV), this is a very reasonable number to use, likely moreso than population density, as it informs the number of interacting individuals who may come in contact with each other and spread transmissible disease.
http://www.jstor.org/discover/10.2307/2343186?sid=21105263993991&uid=70&uid=4&uid=2&uid=2129
The Critical Community Size for Measles in the United States
M. S. Bartlett
Journal of the Royal Statistical Society. Series A (General)
Vol. 123, No. 1 (1960), pp. 37-44
Urbanization and humidity shape the intensity of influenza epidemics in U.S. cities. Benjamin D. Dalziel, Stephen Kissler, Julia R. Gog, Cecile Viboud, Ottar N. Bjørnstad, C. Jessica E. Metcalf, Bryan T. Grenfell. Science Oct 2018 : 75-79
How do transportation and urbanization affect infectious disease?
Measles is highly transmissible. For visualizations of its 19th century geographic patterns, including death rates along the Missouri, a major route of travel, and relative death rates of urban and rural areas, see here:
Do the ways people get around in a city impact disease dynamics?
Does reducing dominant competitors increase populations of subordinates? If pathogens are subordinates in communities where commensals are dominants, will they be likely to cause disease?
http://www.ncbi.nlm.nih.gov/pubmed/8691391
In most ecological communities, there are a few dominant (abundant) species, and many subordinate (rare) species. If we assume that this is due to superior competitive abilities of those dominants, then if something, like an antimicrobial, reduces their numbers, then presumably one of the subordinates will increase in population.
This suggests that pathogens might be “held in check” by commensals or mutualists with superior competitive abilities in their mutual environments, which further suggests that simple presence of a pathogen does not necessarily mean that individuals who come in contact with those pathogens will get sick from them, if there are accompanying commensals or mutualists there as well, to hold the pathogen numbers low enough that they will not be problematic.
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