{"id":3034,"date":"2020-04-18T18:49:19","date_gmt":"2020-04-18T18:49:19","guid":{"rendered":"https:\/\/students.pingry.org\/record\/?p=3034"},"modified":"2020-04-18T18:53:20","modified_gmt":"2020-04-18T18:53:20","slug":"epidemiology-math-problems","status":"publish","type":"post","link":"https:\/\/students.pingry.org\/record\/2020\/04\/18\/epidemiology-math-problems\/","title":{"rendered":"Epidemiology Math Problems"},"content":{"rendered":"<p>[et_pb_section fb_built=&#8221;1&#8243; _builder_version=&#8221;3.18.9&#8243;][et_pb_row _builder_version=&#8221;3.18.9&#8243;][et_pb_column type=&#8221;4_4&#8243; _builder_version=&#8221;3.18.9&#8243; parallax=&#8221;off&#8221; parallax_method=&#8221;on&#8221;][et_pb_text _builder_version=&#8221;3.18.9&#8243;]<\/p>\n<p><span style=\"font-weight: 400\">In these confusing times there\u2019s a certain sense of power that comes with understanding, or at least trying to understand, the dynamics of disease spread and epidemiology. I certainly felt that as I\u2019ve looked into the mathematics disease modeling over the course of this quarantine\u2013\u2013a field that is absolutely fascinating, empowering, and daunting all at once. I recommend checking out <\/span><a href=\"https:\/\/students.pingry.org\/record\/2020\/04\/13\/mitigating-the-spread-of-covid-19-in-quarantine\/\"><span style=\"font-weight: 400\">Julian Lee\u2019s article<\/span><\/a><span style=\"font-weight: 400\"> on his original disease modeling application, which describes the effects of visiting friends in a quarantine (his application is a randomized agent-based model as opposed to the more top-down mathematical models you\u2019ll see here).<\/span><\/p>\n<p><span style=\"font-weight: 400\">In this article, I present three epidemiology thinking problems, in ascending orders of difficulty, meant to put you in the position of the disease modeler. Have fun!<\/span><\/p>\n<p>[\/et_pb_text][\/et_pb_column][\/et_pb_row][\/et_pb_section][et_pb_section fb_built=&#8221;1&#8243; _builder_version=&#8221;3.18.9&#8243;][et_pb_row _builder_version=&#8221;3.18.9&#8243;][et_pb_column type=&#8221;4_4&#8243; _builder_version=&#8221;3.18.9&#8243; parallax=&#8221;off&#8221; parallax_method=&#8221;on&#8221;][et_pb_image max_width=&#8221;50%&#8221; src=&#8221;https:\/\/students.pingry.org\/record\/wp-content\/uploads\/sites\/3\/2020\/04\/MathProblem.png&#8221; _builder_version=&#8221;3.18.9&#8243; module_alignment=&#8221;center&#8221;][\/et_pb_image][et_pb_text text_line_height=&#8221;1.3em&#8221; _builder_version=&#8221;3.18.9&#8243; text_font=&#8221;||||||||&#8221; inline_fonts=&#8221;Inconsolata&#8221;]<\/p>\n<p><span style=\"font-family: Inconsolata;font-weight: normal;font-size: small\"><b>Fig: <\/b>A graphical representation of an SIR (Susceptible-Infected-Recovered) Disease Model. The green curve is the curve that our social distancing efforts are \u201cflattening.\u201d This is the classic, top-down disease modeling approach<\/span><\/p>\n<p>[\/et_pb_text][et_pb_text text_line_height=&#8221;1.3em&#8221; _builder_version=&#8221;3.18.9&#8243; text_font=&#8221;Inconsolata||||||||&#8221; header_font=&#8221;||||||||&#8221; inline_fonts=&#8221;Inconsolata&#8221;]<\/p>\n<p><span style=\"font-family: Inconsolata;font-weight: normal;font-size: small\">1) In epidemiology, R0 (\u201cthe basic reproductive number\u201d or \u201cr-naught\u201d) is defined as the maximum number of new cases expected per infected person. The R0 of COVID-19 has been estimated to be 2.28 (Zhang, et al). An infected individual is expected to cause \u00df new cases per day. This is essentially the \u201cbirth rate.\u201d Meanwhile, \u03b4 is the expected proportion of cases dying on a given day. This is essentially the \u201cdeath rate.\u201d Describe R0 in terms of \u00df and \u03b4.<\/span><\/p>\n<p><span style=\"font-family: Inconsolata;font-weight: normal;font-size: small\">2) Does R0 tend to decrease, increase, or remain the same as a virus grows in an isolated population? Why or why not?<\/span><\/p>\n<p><span style=\"font-family: Inconsolata;font-weight: normal;font-size: small\">3) Consider the following differential equation to describe the spread of COVID-19,\u00a0<span>where \u00df and \u03b4 have the same values defined in problem 1.\u00a0<\/span><\/span><\/p>\n<p>[\/et_pb_text][et_pb_image max_width=&#8221;23%&#8221; src=&#8221;https:\/\/students.pingry.org\/record\/wp-content\/uploads\/sites\/3\/2020\/04\/mathEquation2-1.png&#8221; _builder_version=&#8221;3.18.9&#8243; module_alignment=&#8221;left&#8221;][\/et_pb_image][et_pb_text text_line_height=&#8221;1.3em&#8221; _builder_version=&#8221;3.18.9&#8243; text_font=&#8221;Inconsolata||||||||&#8221; header_font=&#8221;||||||||&#8221; inline_fonts=&#8221;Inconsolata&#8221;]<\/p>\n<p><span style=\"font-weight: normal;font-family: Inconsolata;font-size: small\">This is essentially a fancy mathematical way of saying that the rate at which the infection spreads is dependent on the number of people infected as well as the difference between the virus\u2019 birth and death rates. In what ways does this model oversimplify real-life disease spread?<\/span><\/p>\n<p><span style=\"font-family: Inconsolata;font-weight: normal;font-size: small\">(Problems inspired by Rob J. de Boer\u2019s <i>Modeling Population Dynamics: a Graphical Approach, <\/i>available here: <a href=\"http:\/\/theory.bio.uu.nl\/rdb\/books\/mpd.pdf\">http:\/\/theory.bio.uu.nl\/rdb\/books\/mpd.pdf<\/a>)<\/span><\/p>\n<p>[\/et_pb_text][\/et_pb_column][\/et_pb_row][\/et_pb_section][et_pb_section fb_built=&#8221;1&#8243; _builder_version=&#8221;3.18.9&#8243;][et_pb_row _builder_version=&#8221;3.18.9&#8243;][et_pb_column type=&#8221;4_4&#8243; _builder_version=&#8221;3.18.9&#8243; parallax=&#8221;off&#8221; parallax_method=&#8221;on&#8221;][et_pb_divider divider_weight=&#8221;2px&#8221; _builder_version=&#8221;3.18.9&#8243;][\/et_pb_divider][\/et_pb_column][\/et_pb_row][\/et_pb_section][et_pb_section fb_built=&#8221;1&#8243; _builder_version=&#8221;3.18.9&#8243;][et_pb_row _builder_version=&#8221;3.18.9&#8243;][et_pb_column type=&#8221;4_4&#8243; _builder_version=&#8221;3.18.9&#8243; parallax=&#8221;off&#8221; parallax_method=&#8221;on&#8221;][et_pb_toggle title_level=&#8221;h6&#8243; text_orientation=&#8221;center&#8221; title=&#8221;Click for Solutions!&#8221; _builder_version=&#8221;3.18.9&#8243; open_toggle_text_color=&#8221;#ffffff&#8221; open_toggle_background_color=&#8221;#0063a7&#8243; closed_toggle_text_color=&#8221;#f9f9f9&#8243; closed_toggle_background_color=&#8221;#0063a7&#8243; title_font=&#8221;|600|||||||&#8221; title_font_size=&#8221;16px&#8221; body_font=&#8221;||||||||&#8221; module_alignment=&#8221;center&#8221; body_text_color=&#8221;#ffffff&#8221;]<\/p>\n<p style=\"text-align: left\"><span style=\"font-weight: 400\">1) R0 = \u00df\/\u03b4\u00a0 (1\/\u03b4 is the mean number of days someone with the virus is expected to live.)<\/span><\/p>\n<p style=\"text-align: left\"><span style=\"font-weight: 400\">2) R0 decreases; as an infection grows, there will be more infected individuals around a given infected person, meaning that there are fewer people to infect.\u00a0<\/span><\/p>\n<p style=\"text-align: left\"><span style=\"font-weight: 400\">3) There are a <\/span><i><span style=\"font-weight: 400\">lot<\/span><\/i><span style=\"font-weight: 400\"> of answers to this question, which highlights the limitations of this top-down mathematical modeling. Here are a few.\u00a0<\/span><\/p>\n<ul>\n<li style=\"font-weight: 400;text-align: left\"><span style=\"font-weight: 400\">The \u00df value should not apply only to the infected population, but also to the healthy susceptible population.\u00a0<\/span><\/li>\n<li style=\"font-weight: 400;text-align: left\"><span style=\"font-weight: 400\">This model does not take into account the recovery rate.<\/span><\/li>\n<li style=\"font-weight: 400;text-align: left\"><span style=\"font-weight: 400\">The virus\u2019 birth rate will change, not only depending on the number of people with COVID but also depending on how well the population responds (social distancing, hand-washing, etc)<\/span><\/li>\n<li style=\"font-weight: 400;text-align: left\"><span style=\"font-weight: 400\">The death rate will change based on what treatments are available.\u00a0<\/span><\/li>\n<\/ul>\n<p>[\/et_pb_toggle][\/et_pb_column][\/et_pb_row][\/et_pb_section]<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In these confusing times there\u2019s a certain sense of power that comes with understanding, or at least trying to understand, the dynamics of disease spread and epidemiology. I certainly felt that as I\u2019ve looked into the mathematics disease modeling over the course of this quarantine\u2013\u2013a field that is absolutely fascinating, empowering, and daunting all at [&hellip;]<\/p>\n","protected":false},"author":32,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"on","_et_pb_old_content":"","_et_gb_content_width":"","footnotes":""},"categories":[220,205],"tags":[],"class_list":["post-3034","post","type-post","status-publish","format-standard","hentry","category-fun","category-noah"],"_links":{"self":[{"href":"https:\/\/students.pingry.org\/record\/wp-json\/wp\/v2\/posts\/3034","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/students.pingry.org\/record\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/students.pingry.org\/record\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/students.pingry.org\/record\/wp-json\/wp\/v2\/users\/32"}],"replies":[{"embeddable":true,"href":"https:\/\/students.pingry.org\/record\/wp-json\/wp\/v2\/comments?post=3034"}],"version-history":[{"count":2,"href":"https:\/\/students.pingry.org\/record\/wp-json\/wp\/v2\/posts\/3034\/revisions"}],"predecessor-version":[{"id":3041,"href":"https:\/\/students.pingry.org\/record\/wp-json\/wp\/v2\/posts\/3034\/revisions\/3041"}],"wp:attachment":[{"href":"https:\/\/students.pingry.org\/record\/wp-json\/wp\/v2\/media?parent=3034"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/students.pingry.org\/record\/wp-json\/wp\/v2\/categories?post=3034"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/students.pingry.org\/record\/wp-json\/wp\/v2\/tags?post=3034"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}