Examples of the Epidemiological Triad
Let’s have a look at some examples of the epidemiological triad in motion. For this train, the GIDEON database was used. It’s a handy method to seek for illnesses and get all the data wanted in a single place.
Dengue
Dengue is a uncared for tropical illness (NTD) however is now thought-about a possible pandemic menace because it spreads quickly to non-endemic areas. So, let’s apply the epidemiological triad to dengue and study extra.
Agent: Flaviviridae, Flavivirus, Dengue virus
Host: People, intermediate hosts: mosquitos (Stegomyia (Aedes) aegypti, S. albopictus, S. polynesiensis, S. Scutellaris), monkeys in Malaysia and Africa
Setting: breeding grounds for mosquitoes like stagnant water, open gutters, centralized however unclean water provide, lack of entry to supportive care, urbanization, deforestation, local weather change
Dialogue: At its most simplistic mannequin, the epidemiological triad for dengue will comprise the dengue virus because the agent, people because the host, and contaminated water because the atmosphere. Nevertheless, the mannequin can (and may) be expanded to incorporate intermediate hosts (vectors) just like the aedes mosquitoes which can be largely liable for the unfold.
Environmental components should embrace socio-economic and infrastructure-related components, like entry to healthcare. For instance, whereas 80% of dengue instances are delicate or asymptomatic, extreme dengue can develop throughout the essential part (3-7 days after getting sick). Signs can out of the blue worsen, resulting in problems and even loss of life with out hospitalization and shut medical monitoring. Entry to healthcare close by is a essential ‘environmental’ issue. Equally, local weather change has been liable for dengue now spreading to non-endemic areas, making dengue a pandemic-level menace.
Polio
In September 2022, the State of New York declared an emergency as a consequence of polio instances spreading. The poliovirus was detected in sewage water samples. Polio is extremely contagious; the virus could cause complete paralysis inside a number of hours. There isn’t a remedy for polio; prevention is essential to curbing its unfold. Let’s have a look at the epidemiological triad for polio.
Agent: Picornaviridae, Picornavirus: Polio virus
Host: People
Setting: Fecal matter, contaminated water or meals, unsanitary practices (not washing fingers with cleaning soap), lack of entry to polio vaccines, vaccine hesitancy, mistrust associated to the healthcare system, interruptions to vaccine drives as a result of COVID-19 pandemic, and vaccine provide, storage, and distribution.
Dialogue: Polio will be prevented and eradicated with the suitable public well being responses, sources, and consciousness in regards to the energy of the polio vaccine. Whereas it has one agent and one host, the atmosphere holds a mess of things to handle earlier than the world can eradicate the illness. For instance, a scarcity of entry to polio vaccines could possibly be as a consequence of inadequate provide, a world pandemic, or a pure catastrophe interrupting scheduled vaccine drives. Different environmental components embrace misinformation (and disinformation) about vaccines. As soon as these factors are mapped out on the epidemiological triangle, they are often prioritized and addressed.
Ebola
Ebola is prioritized by the World Well being Group (WHO) for analysis and improvement as a consequence of its potential to trigger a widespread public well being disaster. The illness is also called Ebola Virus Illness (EVD) and, beforehand, Ebola hemorrhagic fever. Though uncommon, it might probably trigger extreme sickness and deadly infections. The case-fatality price is 50% — extraordinarily excessive. What would the epidemiological triangle for Ebola appear to be?
Agent: Viruses within the genus ebolavirus, together with Zaire ebolavirus, Sudan ebolavirus, Taï Forest ebolavirus, and Bundibugyo ebolaviruses.
Host: People, primates (apes and monkeys), guinea pigs, fruit bats, porcupines, and forest antelopes
Setting: Blood or physique secretions from an contaminated host (alive or lately lifeless), contaminated needles and syringes, breastfeeding from an contaminated father or mother, sexual contact, respiratory/air, entry to supportive care and vaccines, PPE (protecting gear) for healthcare staff, unsafe burials, unsafe sexual practices, inhabitants development, urbanization, and uncooked meat consumption, globalization.
Dialogue: Ebola just isn’t a excessive danger for speedy outbreak unfold as a result of it isn’t unfold by the air, water, or meals. Direct contact with blood or different physique fluids is how Ebola is transmitted. Nevertheless, lately, deforestation as a consequence of human encroachment has disturbed fruit bats’ pure habitat, a standard ebolavirus host. This displacement can enhance the danger of zoonotic spillover of Ebola from wild animals to people. There are two licensed vaccines towards Ebola, however portions are restricted. Nevertheless, in January 2021, a world stockpile of Ebola vaccines started to assist mitigate the danger of a large-scale Ebola outbreak.
As you see, epidemiological triangles are a good way to prepare epidemiology info, present a visible snapshot of infectious illness, and train the rules of epidemiology.
GIDEON, the world’s main infectious illnesses database, is dedicated to advancing the worldwide effort towards infectious illnesses. An enormous a part of this technique is to empower epidemiology and public well being academics and school with lesson plans, together with a lesson plan on epidemiological triangles.
