Essay about Transmission of the Plague to Humans

"The Black Death" is known as the worst natural disaster in European history. The plague spread throughout Europe from 1346-1352. Those who survived lived in constant fear of the plague's return and it did not disappear until the 1600s. Not only were the effects devastating at the time of infection, but during the aftermath as well. "The Black Death" of the fourteenth century dramatically altered Europe's social and economic structure.

The book When Plague Strikes, is about 3 deadly diseases. It 's about the Black Death, Smallpox, and AIDS. Each of these diseases can cause a serious outrage of death. The book also tells about how doctors try to come up with treatments, medicines, and antibiotics to try and cure these diseases. All these diseases got the best out of everyone. Some people reacted differently than others with these diseases. All the diseases came in play in A. D. 1347, when the Black Death broke out for the first time in what’s today is know. As southern Ukraine.

Fleas are external parasites that survive on the blood that they suck from their hosts. They are agile, wingless insects that are usually measure less than 3 mm in length. Although many people associate fleas with dogs and cats, they are quite willing to feed on

The Great Plague of 1665 in London killed eight thousand people a week at its peak. Surgeons lanced buboes in an ineffective attempt to rid the body of bad humors (The Great Plague). Yersinia pestis lives in fleas on many types of rodent species. The rodents serve as long-term reservoirs for the bacteria without the rodents experiencing excessive die-off. Dogs and cats can host fleas infected with Yerisina pestis (Ecology). This makes the plague a zoonotic disease. The way the bacterium was transmitted in London was by the bites of infected fleas. Other animals can become infected by fleas that traveled from another host. Epizootic infections are then transferred to humans according to the Center for Disease Control. In 1666 London had a fire and the city was cleaned and better sewer systems were built. These improvements reduced the number of rats and ended the

The lifecycle of a heartworms begins when a female mosquito ingest blood containing microfilariae from a heartworm infected animal. Inside the body of the mosquito, the microfilariae develops into first stage larvae (L1) and then undergoes two more process to develop into third stage larvae (L3) of which is the infective stage. Depending on the temperature, this development process can take between eight and thirty days. At this point, when the infected mosquito attaches to a cat and feeds on its blood, the third-stage larva is transferred into the mosquito bite wound. Within three days of entering the cat, the L3 molt to the L4 stage in the tissues and muscles that lay just below the skin of the cat. After about two months of migrating through the muscles and tissues, the L4 undergoes a final development into immature adult heartworms. Seventy to ninety days post infection, the immature adult heartworms then enter a peripheral vein and are carried by the cat’s blood circulation system to the caudal pulmonary arteries. This is where the majority of heartworms are cleared from the cat due to a mass immune response, but a few may continue development into adults. Once the heartworm develop into adults, they invade the heart first and then spread to other organs in the body and cause

Since the feline species are the only recognized host of T. gondii, the parasite must pass through the feline digestive system in order to complete its life cycle and reproduce (NOAA, 2013). The parasite multiplies within the feline digestive tract, releasing the parasitic eggs through the cat’s feces (NOAA, 2013). The parasitic eggs infect other non-feline species, including mice and birds, which is a common source of transmission to uninfected cats (NOAA, 2013). Rainfall can wash the cat feces into the ocean where the parasitic eggs remain viable for up to two years (NOAA,

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 .

Ticks acquire the bacterium by feeding on reservoir hosts (organisms that sustain certain parasites), such as white-footed mice (1).

B.quintana is a part of the bacteria kingdom and was originally known as Rickettsia quintana in the early 1900s when trench fever was first identified. Foucault, Brouqui, and Raoult state, “R.quintana was classified in the genus Rochalimaea, tribe Rickettsiae, family Rickettsiaceae” (2006). However, the genus Bartonella was removed from the order and put into another one. The genus now consists of many different species including B. quintana. Like any other bacteria and organism, B. quintana has it’s own characteristics that make it special. It is facultative which means that it can develop and grow in both aerobic and anaerobic environments. This bacteria is also intracellular and that means that it reproduces inside of their hosts cells. B. quintana is gram-negative and rod shaped and often compared to B. henselae because of their similar structures. Humans are infected with this disease through the vector named Pediculus humanus corporis, commonly known as lice. The bacteria has been observed in erythrocytes and also erythroblasts in bone marrow (Foucault, Brouqui, and Raoult, 2006). All these characteristics about B. quintana make trench fever an important disease that infects humans all over the

hominis gets inside the intestinal tract. All we know is that the cyst wall thins out and thickens thorough the intestinal tract, and then it exits through the exertion in form of feces. Therefore, the parasite will be transmitted in many ways. But, the form that spreads the most parasite is the feces-oral method. For example, if someone uses the restroom and does not wash their hands, and afterwards they go into the kitchen and handle food they are spreading B. hominis to the person who will take the food. B. hominis has no know signs or symptoms. Someone who has B. hominis might not even know unless they are tested for it’; since, the symptoms are difficult to show. But, it is well known symptom that this parasite shows are diarrhea. In result of this, the parasite is carried through diarrhea or digestive

The complexity of S. stercoralis’ life cycle begins with its alternation between free-living and parasitic cycles.1 When the soil is contaminated with the infective filariform larvae, humans get infected through the skin.1 The infective filariform larvae penetrate the human host and reach the small intestine, where they mature into adults and produce eggs through parthenogenesis.2 The eggs hatch in the small intestine and eventually become larvae that are passed in the stool.6 The rhabditiform larvae passed in the stool become either infective filariform larvae or into free-living adults that reproduce outside the host environment.6 Some rhabditiform larvae are not completely excreted in the host’s feces, and they reinvade the small intestine or perianal skin and cause autoinfection.6 With the ability to autoinfect the hosts, S. stercoralis is potentially dangerous and fatal. Most chronic infections remain

When in a new host the parasites find their way into the brain and that’s when the problems arise for humans and other animals. These parasites, however, cannot complete a life cycle in any other host besides cats so it is believed that they affect the brains of other organisms as a way to get back to their proper hosts. For example, in rats, this parasite can cause them to love the smell of cats. This results in rats changing their behavior and seeking out cats rather then running away from them.

+Log:+ What sets the object apart from other members of Trichinella is that in all infections, a small portion of the worms colonize the central nervous system. There, they secrete a compound that increases altruism and brings a conviction that the host's tissues are delicious. Hence, the host will try to “help” others by feeding them pieces of his own flesh.

When it rains the bacteria can also be washed into small bodies water, then animals such as dogs that swim in or drink the contaminated water will be infected with the bacteria. Another way is through open wounds such as bites, in which the bacteria goes into the body from there.

     Transmission of the parasite can occur in several different ways. Direct transmission can occur by handling infected animal or human feces. One quarter of reported direct transmission infections occurred by direct contact with feces, while the rest were reported to have happened by person to person contact (Donnelly & Stentiford, 1997).