Pathogens And Bio Toxins

contaminated water or food
17. For each pathway listed in question #16, explain the relationship of the mode of transmission to the virulence of the invader.

I was observing the spread of the plague right before my eyes. I knew how the three types of plague were transmitted but the humans did not. The three types were the Bubonic, Pneumonic and Septicemic plague. The Bubonic plague was the most common plague in medieval Europe. It was transmitted by infected fleas that were carried by rats, when the rat died the flea would jump to a human to feed from their blood. The human bitten by the flea, was then infected and faced certain death, the flea would then find a new human to feed off. The Pneumonic plague, being the second most common type in medieval Europe, was far more deadly and contagious than the Bubonic plague. The Plague would attack a human's respiratory system and was spread through the air by a victim's cough. The last type of plague was the Septicemic, it was the rarest and deadliest form of the Black Death. The Septicemic plague was also spread by fleas, like the Bubonic plague, but moved directly to a human's

The carriers of this disease were rats and fleas. It first started off with fleas, then fleas would then jump on rats and the rats would give the disease to humans. The disease didn 't harm the fleas and the rats could only take so much without showing ill effects. Rats would get on ships and make everyone on the ships sick. This is how the Plague traveled.

Infections can be spread through many things, these include; food borne infection, person to person, water borne infection, airborne infection, insect borne infection and fomites.

Multiple factors contributed to the spread of this deadly plague, that historians believed originated in Asia and then spread along trade routes to Europe and England. Infected rats carrying fleas that were infected with the Plague took rides on boats and travelled through the routes. While this is how the Plague

The spread of infection requires three elements. The first is; A source of infecting microorganisms: This could be an exogenous infection which arises from microorganisms external to the individual and do not exist as normal flora. They usually have a preferred portal of entry like the gastrointestinal for Salmonella. Another source is endogenous infections which can occur when part of the client’s flora becomes altered and an overgrowth results e.g. Yeasts infection. Second requirement is means of transmission for the microorganism, which also explains the three primary modes of pathogen transmission. For example, vertical transmission is when a pathogen is

The cause of the outbreak of the plague was initially unknown, and it was not until 1899 that it was discovered to have come from a bacteria called Yersinia Pestis. This bacteria lived in the digestive system of fleas, who in turned lived on rats. When these fleas bit people, the bacteria would enter the bloodstream. Other ways the disease spread was airborne; coughing, sneezing, even breathing. (Ollhoff 10). Sometime around

“Bioterrorism remains a major threat for the United States despite more than $65 billion spent on protecting the country from myriad dangers, the Bipartisan WMD Terrorism Research Center said in its latest report Wednesday. The center's Bio-Response Report Card evaluated U.S. preparedness for countering threats from bioterrorism and found the country remains vulnerable to multiple threats and "largely unprepared for a large-scale bioterrorist attack."”(UPI.com, 2011). There have been over a dozen leading U.S. bio-defense experts that have taken part in figuring out where we are exactly as a county and what the effects of a terroristic attack

Disease spread across the globe originating from Chinese trading ships in the 13th century which carried infected rats: “The Black Death reached England in August 1348. It first appeared in Dorset, and had spread to London by November” (Somerville). The Black Plague reached England during the mid 14th century, and repeated outbreaks occurred in cities such as London until the 1800’s. Infected rats made their way off ships towards land, and began the horrific plague. Although many diseases spread through the air, the plague offered an extraordinary spread. Regarding this information, in article one it says, “Bubonic Plague is carried by black rats, and spreads to humans by the fleas that infest them” (Somerville). This evidence assists in explaining that the plague is transmitted when a flea drinks contaminated rat blood. Then, a flea bites a human, and they become infected with a very menacing bacterium. The complex diffusion of The Bubonic Plague from bacterium, to rats, ships, and land show it’s painstaking

It spread through fleas that were on rats that were on the ships that came to Europe. Then, fleas bit the rats and the rats blood, that was infected by the black plague virus, was injected into the human’s blood was infected. Then a clueless infected person would walk around Europe’s cities and infecting anyone who simply coughed or sneezed and then suddenly the virus was airborne. Moreover, this deadly disease just became 10x more dangerous. That is how so many people became infected and were dead suddenly the next day.

It would travel person to person through the air as well as through the bite of infected fleas. Most medical historians believed that this germ was spread in many different ways but the respiratory form was what caused the deaths of most of its victims. The military then and now used the plague as a war weapon. “As a highly contagious disease with an extremely high mortality rate, if left untreated, Yersinia Pestis has been used as biological warfare for centuries. Some warfare strategies include catapulting corps over walls, dropping infected fleas from airplanes and areosaling the bacteria during the cold war. More recently the plague raised concerns as an important national security threat because of its potential use by terrorist.” (Stenseth, 2008, para 8). They would also put infected rats as well as flies into water sources. Although the plague had run its course by the early 1350’s, it has reappeared every few generations ("black death," n.d.). According to many historians’ the plague has permanent homes in Asia, Siberia, China, Iran, Libya, Arabia and East

The bubonic plague has been around for almost two thousand years. In most early cases the plague was spread from China along the Silk Road. The Silk Road was the over land trade route from the orient that silk, spices, and other trade able goods from the east to western Europe. In most cases rats carrying the Oriental Rat Flea or another animal carrying the flea would move to a new location. Once that animal died the flea would move to another host which could be a human. Once bitten by the flea a bubo begins to form when the bubo begins to ooze fluid the illness can then be passed through touch. As stated above in the Middle

A communicable disease chain is the mechanism by which an infective agent or pathogen is transmitted. The chain requires an infective agent, a source of infection, a mode of transmission and a host. An example of an infective agent could be bacteria, a virus, fungus, protozoan or helminth. The source of infective agents can be transmission from host to host, an infected human or animal, insects, soil or livestock. The mode of transmission is how the infective agent is carried from host to host. Transmission can be by air, ingestion or physical contact. To complete a life cycle or to replicate, the infective agent requires a host.

How the disease was transmitted was further looked on by Nelson (1995). According to the said author, the disease was transmitted primarily by fleas and rats. The stomachs of the fleas were infected with bacteria known Y. Pestis. Nelson held that “the bacteria would block the "throat" of infected fleas so that no blood could reach their stomachs, and they grew ravenous since they were starving to death” (1995, par. 14). The bacteria would then attempt to suck up blood from their victims, only to disgorge it back into their preys' bloodstreams (Nelson, 1995). Now, however, the victims' blood was mixed with Y. Pestis. Fleas infected rats in this fashion, and the rats spread the disease to other rats and fleas before dying (Nelson, 1995). Without rodent hosts, the fleas then migrated to the bodies of humans and infected them in the same fashion as they had the rats .

The Bubonic Plague and a variation called the septicemic plague was spread throughout Europe by oriental rats that carried infected fleas. Little is known to why the infection never seemed to affect the carrier rats. Infected fleas were being starved by the infection, so they began feasting upon the people they came into contact with. These fleas coming into contact with any human being would infect the human with the disease. These people were now carriers of the Bubonic plague or Black Death. These infected people would then spread the disease by coughing or coming into direct contact with another human being. However, this disease, since not being transmitted via rat would now be called the Pneumonic Plague. (www.insecta-inspecta.com).