1. What is a disease vector? Discuss the roles and importance of disease vectors in the transmission of diseases. 25 pts.
A disease vector is any agent that transmits and carries an infectious pathogen into another living organism. These vectors have immunity to the pathogen and thus allows for the successful transport of the pathogen. Not every vector is able to carry every pathogen and ecological restrains also limit the spread of the disease due to the inability of the vector to survive in different kinds of environments.
Arthropods can serve as vectors and play an important role in disease transmission. These vectors include mosquitoes, fleas, sand flies, lice, ticks, and mites. They are responsible for the transmission of several diseases. These vectors feed on blood at some or all stages of their life cycles. The hematophagous lifestyle of these arthropods allows the pathogens to enter the blood stream of the host. For example, the anopheles mosquito is a vector for malaria, filariasis,
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The transmission of pathogens from current to future host follows a repeating cycle. The cycle can be simple with a direct transmission or complex where it goes through multiple intermediate hosts or vectors. These cycles are called the disease transmission cycles. A cycle has many elements: the pathogen, the organism that causes the infection; the host, the infected organism carrying the pathogen; the exit, the method the pathogen follows to leave the body of the host; transmission, describes how the pathogen is transferred from host to susceptible organism; the environment, where the transmission of the pathogen takes place; the entry, the method followed by the pathogen to enter the body of the new host; and the susceptible organism, a person or animal who is receptive to the
These viruses include the following: herpes, measles, fowl pox, mumps, and equine encephalitis. It was said that Henrietta’s cells helped launch the field of virology. The book also mentions how viruses reproduce by injecting some of their genetic material into a living cell, essentially reprogramming the living cell so it reproduces the virus instead of itself which is a concept we have learned this semester (Skloot, Location
When a virus meets a host cell, it injects its genetic material into its host, taking over the host’s
Rats acted as vectors as they carried the infected fleas into the cities. One factor that influenced the spread was that in 1350 hygiene was inadequate and often food and faeces were left in the streets this meant that the cities ect was teeming with rats as they had an appropriate food source and habitat. Humans lived alone side rats but since the rats carried the fleas the fleas would bite the people who lived there thus infecting them. The next factor is that the rats began to die of the plague so household pets or other animals started feeding on them thus becoming infected. Since pets were becoming more common they had access to the household.
The Columbian Exchange: Positive or Negative? Christopher Columbus is credited with ‘discovering’ the Americas. After he ‘discovered’ them, the Old World and the New World began trading plants, animals, and diseases; otherwise known as the Columbian Exchange. The plants and animals were greatly beneficial, but the diseases were quite the opposite, killing many of the Native Americans.
Another negative effect of the Columbian Exchange was the disease that it brought to the New World, which was a leading cause of widespread death throughout the area. When the Europeans sailed across the Atlantic, they brought all of the germs that were native to the Old World, such as smallpox and tuberculosis, with them. The Europeans were not affected by this, as they had already developed an immunity to these bacteria. The natives, however, were impacted greatly by the germs that were brought to their homeland, for they had never seen viruses like the ones brought aboard European ships. Diseases spread quickly amongst indigenous peoples, killing, in some places, 100% of a population as they travelled from person to person.
This specific bacteria attacks the lymph system causing the infection to spread throughout the body. The reservoirs of this bacteria and disease are mice, rats, squirrels and other small animals. A reservoir is a host of an infection. The vector, meaning carrier, is insects such as fleas and
The plague raged throughout Europe from the fifteenth to the eighteenth century evoking various responses from the people who experienced its terror. It affected all regions of Europe, killing one-third of the population. Various responses to the plague expressed different beliefs and concerns including exploitation, fear, and religious superstition. During the course of the plague these beliefs and concerns underwent change. During the outbreak of the plague fear dominated Europe, and as time passed fear became more irrational and superstitious.
The arrival of Christopher Columbus to the Americas in 1492, started what may be described as a wave of infectious disease and death. With the discovery of the New World came a flood of colonist and conquistadors. As the Europeans explored and discovered foreign unknown lands, the natives had to deal with a foreign matter of their own. “Europeans and the African Slaves they brought inadvertently carried bacteria and viruses across the Atlantic that Native Americans had never encountered. ”(Campbell, 2008, p.3).
Smallpox is a highly contagious and fatal disease that had a huge impact on the human population. It is thought to have been originated from India or Egypt at least 3,000 years ago. Smallpox is caused by two variations of the variola virus, variola major and variola minor. Variola major is the most common form of smallpox. It enters the body through the lungs and is carried to the internal organs.
Bacteria multiple itself by division. Viruses and bacteria both are microscopic, contain proteins, and cause disease. 2. (a) A vector is known as an infected insect that carries the disease from one animal to another and from one plant to another. The difference between a vector and a host is a vector is the
Some diseases tramsitted by the Europens were diseases such as “smallpox, measles, malaria, yellow fever, influenza,” (Malone, Cary et al.) and other Old Wolrd diseases. This devestaing elemet of the transmisson of European diseases is the easibility in which the diseases were passed; through air. Native Americans didnt have to come inot contact with Europeans to become infected with their diseases. Their immune systems hadnt experienced the Old World diseases, populations and cultures were wiped
A virus is an infective agent that usually consists of a protein coat with a nucleic acid molecule. Viruses do not reproduce through asexual reproduction. Instead, they attach themselves to the cells in their victim’s body to create more viruses. Over the years, vaccines for certain viruses have been created to help humans combat them. However, for viruses such as Ebola, there have been no drugs approved to cure them.
During the mid-fourteenth century, a plague hit Europe. Initially spreading through rats and subsequently fleas, it killed at least one-third of the population of Europe and continued intermittently until the 18th century. There was no known cure at the time, and the bacteria spread very quickly and would kill an infected person within two days, which led to structural public policies, religious, and medical changes in Europe. The plague had an enormous social effect, killing much of the population and encouraging new health reforms, it also had religious effects by attracting the attention of the Catholic Church, and lastly, it affected the trade around Europe, limiting the transportation of goods. As a response to the plague that took place
I have always wanted to pursue a career related to the medical field, and it wasn't until my freshman year of college that I encountered the area of public health. I was immediately drawn to the specific area of epidemiology and infectious diseases. I am now a junior at the University of Texas majoring in Public Health with a concentration in microbiology and infectious diseases. I find epidemiology so enthralling, as it is implements ways in which we can scientifically and statistically describe diseases and the mortality/morbidity as well as predict how and why they spread. More so, I think the infectious disease aspect is interesting as well, because while the United States has shifted from burden of infectious disease to that of chronic
Malaria is the most common disease in third world countries with a tropical climate; the disease is caused by a parasite called Plasmodium, which is transmitted through the bites of infected mosquitoes. In the human body, the parasites multiply in the liver, and then infect red blood cells. Symptoms of malaria include fever, headache, and vomiting, and usually appear between 10 and 15 days after the mosquito bite. If not treated, malaria can quickly become life-threatening by disrupting the blood supply to vital organs. In many parts of the world, the parasites have developed resistance to a number of malaria medicines.