Yellow Fever Mosquitos
Introduction:
Yellow Fever used to and still does terrorize individuals in humid hot climates where the vector of the disease, the Aedes aegypti mosquito thrives. People were baffled by how to stop the spread of the disease until one of the largest heavy civil projects to date was started. For the project methods were developed by construction workers and entomologists alike to ensure the success of the massive canal. This was done by examining the various stages the Aedes aegypti mosquito goes through during its life cycle and developing ways to kill them. Construction of the Canal and construction as a whole was impacted greatly by the little Aedes aegypti mosquito.
Construction Field/Yellow Fever Connection:
Construction Engineering Management is the study of construction and all aspects that go into it such as contracts, scheduling, load calculations on buildings and various methods of construction such as post tensioned concrete. Construction Engineering includes many smaller fields such as general, electrical, mechanical, and civil contracting. In the constitution field general contractors oversee all the sub contractors such as electrical and mechanical sub-contractors. The general contractor is the one who coordinates between all the subs to ensure a job is done efficiently and cost-effectively. Construction engineers often work for one of the contractors listed above and they all work closely with architectural engineers as well as structural and mechanical engineers to build structures of all kinds.
Construction engineers are those at the forefront of planning and coordinating the construction of commercial buildings, residential housing, roadways, bridges and pipelines. Some careers that are offered through construction engineering are project engineers, superintendents, and project managers. Typically, those who study construction engineering start out as project engineers and progress to the position of superintendent or project managers. Project managers and superintendents are considered upper-level management and make most of the calls on jobsites in terms of scheduling and how to allocate funds given to them by the company. Project managers in particular are the last say in allocating funds and making decisions on a jobsite. These project managers also make decisions that can directly influence the health and safety of laborers and tradesmen working underneath. For example, project managers can select a set of safety regulations or standards that are above those required by law to ensure the safety of workers, or they can select how to handle illness or sick leave for workers on a jobsite. They also work closely with other professionals such as entomologists and environmental agencies to ensure the safety of workers and to build sustainably.
Construction projects are performed in all types of climates and areas. Rural construction projects in particular can expose many workers to various diseases and threats. One such example was during the construction of the Panama Canal. During this construction project, project managers worked closely with entomologists to control mosquitos that spread Yellow fever on the jobsite.
Panama and Yellow Fever:
Yellow Fever has been an ever-present threat for humans for hundreds of years. Yellow fever is a disease that is primarily in South America and Africa and causes chills, fever, jaundice, bleeding and sometimes even death (Yellow 2023). The construction industry can be especially susceptible to complications involving yellow fever like in the instance of the Panama Canal.
The construction of the Panama Canal was considered an engineering marvel at the time of its construction and still to this day is an impressive feat that connects the Atlantic to the Pacific shortening ship travel times by weeks. The construction of the canal had many challenges but the largest challenge to the canal’s construction was that of yellow fever. The canal’s construction was attempted in the 1880’s by the French but failed miserably by 1889. The French battled to make the canal for years but eventually failed due to the diseases spread by mosquitos which caused around 20,000 workers to die (Tropical 2020).
Years later the United States took over construction of the Panama Canal and the US workers began to experience the same issues as the French did with workers being killed or scared off by yellow fever. This virus brought construction grind to a halt and almost caused the project to fail again (Sutter 2016). The lead engineers in charge of the construction looked for help and found it in Gorgas who was chief sanitary officer. Gorgas reached out to entomologists and Carlos Finley who had studied yellow fever and discovered that Aedes aegypti mosquitos transmitted the disease years earlier in Havanna Cuba (Stutter 2016). Gorgas had sanitary workers drain, or cover with kerosene, all sources of standing water which prevented mosquito larve from developing (Sutter 2016). This proved highly effective and allowed work to continue on the Canal. The methods did receive some backlash as it contaminated surrounding water and killed other animals that inhabited the waters surrounding the canal. Overall, though the eradication methods were highly effective and spearheaded techniques to be used on further construction projects in tropical areas.
Had the Panama Canal not been constructed trade as we know it today in North America would be wildly different. Goods would be more expensive as shipping around South America would take days longer. Additionally the importance of entomology wouldn’t have been realized as quickly as the Panama Canal was one of the first world renowned examples of how beneficial entomology can be in terms of stopping the spread of diseases.
About the Yellow Fever Mosquito:
The mosquito commonly known as the Yellow fever mosquito is responsible for transmitting the potentially deadly yellow fever to people. This disease causes humans to fall ill and sometimes even die. Those who are more susceptible to contracting the virus are those working in close proximity to the mosquito such as construction workers or farmers. The scientific name for the yellow fever is Aedes aegypti. This mosquito is in the order Diptera the family Culicidae the genus Aedes and the species which is Aegypti. The mosquitos prefer humid hot climates such as jungles and require standing water to lay eggs in. Aedes aegypti Is primarily found the ranges pictured right (Zettel 2008).
Life Cycle:
Eggs:
Aedes aegypti Goes through four stages during its life cycle. The first stage is the egg stage. During this stage the mosquitos are long smooth and ovel shaped approximately 1 mm long and black in color. These eggs are laid in batches of 100 to 200 and can survive for months without water waiting to hatch (Zettel 2008).
Larvae:
After the eggs hatch the mosquitos hatch and become larvae. The larvae are long and cylindrical in shape with a tan color and have an eye by their short siphon. The larva’s development varies greatly depending on the temperature of the water they exist in (Zettel 2008).
Pupal:
Following the larvae stage the mosquito enters the pupal stage where they are about 2 mm long and tan in color. During this stage the pupae don’t eat and unlike most other species the pupae will respond to stimuli. This stage lasts approximately two days and ends when the pupae ingests air causing the abdomen to split open and an adult mosquito to emerge (Zettel 2008).
Adult:
The adult mosquito measures 4 to 7 mm in length and are primarily black or dark brown in color often with a white stripe down the thorax. The males are typically smaller the females and eat only nectar. This means female Aedes aegypti are the only ones who can feed on humans. During the construction of the Panama Canal these female mosquitos through blood feeding were the vectors of yellow fever (Zettel 2008). These female mosquitos were controlled during construction by working with entomologists to make the water they need to lay eggs in inaccessible (Sutter 2016).
Pupal
Standing water mosquitos could survive in
https://colinpurrington.com/wp-content/uploads/2018/10/stagnant-water-gutters.jpg
Human Connection:
Entomology and technological advancements played key roles in ensuring its success of the construction of the Panama Canal. Yellow fever ravaged workers in Panama and caused fear amongst them. The French in the late 1800’s failed in their attempt to construct the canal due in a large part to yellow fever infecting and killing workers. It was not understood at the time when the French started construction and even early on during the United States attempt at construction what the source of transmission for yellow fever was. Thus, nothing could be done to stop the virus’s deadly spread.
By the early 1900’s though entomologist studies conducted by Carlos Finley in conjuncture with the Reed commission discovered that the Aedes aegypti mosquito spread yellow fever (Britannica 2022). This discovery and new technological advancements allowed the workers to fight back against the mosquitos that transmitted it.
It was also understood that mosquitos needed standing water to breed, and new technological advancements made it possible to eliminate mosquito breeding grounds. A new highly effective method that was used to make standing water unusable for mosquitos was coating water in kerosine. Additionally cans and other trash that held water were picked up, clogged gutters were repaired and cisterns that held drinking water were replaced with pipes. Some of the technologies developed that were unrelated to breeding were mosquito nets and aggressive fumigation of living quarters anywhere yellow fever cases were reported (Sutter 2016). These new technologies were used simultaneously with entomological studies that mapped out mosquitos breeding habits. This allowed strategic ponds to be hit with kerosine at correct times to ensure mosquito larvae couldn’t survive. The strategies used saw great success and caused the Aedes aegypti mosquito to be largely controlled in the area (Sutter 2016).
The effectiveness of the measures used to control the mosquitoes that transmitted yellow fever altered how people in tropical climates interacted with mosquitos. It made them more aware of the threat mosquitos pose to humans and demonstrated ways to combat the Aedes aegypti mosquito. Additionally, it articulated the need for and importance of entomology in society by demonstrating how there are great benefits to studying how humans interact with bugs.
Works Cited
Britannica, The Editors of Encyclopedia. "Carlos J. Finlay". Encyclopedia Britannica, 29 Nov. 2022, https://www.britannica.com/biography/Carlos-J-Finlay. Accessed 13 August 2023.
“Construction Managers : Occupational Outlook Handbook.” Occupational Outlook Handbook, 16 Nov. 2022, www.bls.gov/ooh/management/construction-managers.htm#:~:text=Construction%20managers%2C%20often%20called%20general,well%20as%20roads%20and%20bridges.
Sutter, Paul S. “‘The First Mountain to Be Removed’: Yellow Fever Control and the Construction of the Panama Canal.” Environmental History, 25 Apr. 2016, www.ncbi.nlm.nih.gov/pmc/articles/PMC8932943/. Accessed 13 August 2023.
“Tropical Diseases and the Construction of the Panama Canal, 1904-1914.” Contagion - CURIOSity Digital Collections, 26 Mar. 2020, curiosity.lib.harvard.edu/contagion/feature/tropical-diseases-and-the-construction-of-the-panama-canal-1904-1914. Accessed 13 August 2023.
“Yellow Fever.” Centers for Disease Control and Prevention, 6 July 2023, wwwnc.cdc.gov/travel/diseases/yellow-fever#:~:text=People%20who%20do%20get%20sick,organ%20failure%2C%20and%20sometimes%20death. Accessed 13 August 2023.
Zettel, Catharine, and Phillip Kaufman. “Featured Creatures .” Yellow Fever Mosquito - Aedes Aegypti (Linnaeus), 1 May 2008, entnemdept.ufl.edu/creatures/aquatic/aedes_aegypti.htm#:~:text=The%20yellow%20fever%20mosquito%2C%20Aedes,the%20United%20States%20for%20centuries. Accessed 13 August 2023.