Essay Identify 3 Ways In Which Microbes/Parasites Move From Host To Host

When we hear the word virus, we usually think of something that makes us sick. A virus is an ultramicroscopic infectious organism that, having no independent metabolic activity, can replicate only within a cell of another host organism. A virus consists of a core of nucleic acid, either RNA or DNA, surrounded by a coating of antigenic protein and sometimes a lipid layer surrounds it as well. The viral genome provides the genetic code for replication, and the host cell provides the necessary energy and raw materials. To fight viruses, we use vaccines. While some may infect a broad range, other viruses can only infect certain kinds of cells. Vaccines are made of inactive, dead or weakened virus cells or protein antigens that can no longer infect

a. Antibodies allow scientists to target and identify specific disease agents because they bind to antigens to counteract them. The more antigens you have, the more antibodies you have, the more the of the virus/bacteria that there is in you.

West Nile Virus is known as an arthropod-born virus, or an arbovirus, and are transmitted and sustained within blood feeding arthropods, such as the mosquito. The disease, while having no apparent effect on the host, is then transmitted as the mosquito takes a blood meal. As the source of infection, the mosquito or other blood feeding arthropod is known as a primary vector. However, because the life cycle of the mosquito is reletively short an additional host is needed to maintain the life cycle of the virus.

Discoveries in DNA, cell biology, evolution, biotechnology have been among the major achievements in biology over the past 200 years with accelerated discoveries and insights over the last 50 years. Consider the progress we have made in these areas of human knowledge. Present at least three of the discoveries you find to be most important and describe their significance to society, health, and the culture of modern life.

In this assignment I am going to explain how infections are caused by, bacteria, viruses, fungi and parasites. I will then explain how pathogenic microorganisms grow and spread.

Indirect transmission of infectious organisms involves vehicles and vectors which carry disease agents from the source to the host.

The author explains the basics of DNA by describing the simple part of it, “proteins are the molecules that do all of the work in every organism, from carrying oxygen, to building tissue, to copying DNA for the next generation” (Carroll 73). He also explained the four bases that are building blocks that are held together by strong bonds and are represented by the letters A, C, G and T. Scientist also learned that A and T always pair with each other as well as G and C, this helps them because if they know one strand of DNA they already know the second because of how the bases match up. The author states that scientists have found about 500 genes that exist in all forms of life, the author explains that these genes are “immortal”. These genes have endured millions of years of evolution and have not been mutated because they are essential for every organism to have; these genes can have important jobs such as decoding of the DNA and RNA and making

The body’s protection against viruses, bacteria and other types of invasions is our immune system (Tortora, 2014).

The virus fuses with the cell’s plasma membrane. The capsid proteins are removed, releasing the viral proteins and RNA. Reverse transcriptase catalyzes the synthesis of a DNA strand complementary to the viral RNA. Reverse transcriptase catalyzes the synthesis of a second DNA strand complementary to the first. The double-stranded DNA is incorporated as a provirus into the cell’s DNA. Proviral genes are transcribed into RNA molecules, which serve as genomes for the next viral generation and as mRNAs for translation into viral proteins. The viral proteins include capsid proteins and reverse transcriptase (made in the cytosol) and envelope glycoproteins (made in the ER). Vesicles transport the glycoproteins from the ER to the cell’s plasma membrane. Capsids are assembled around viral genomes and reverse transcriptase molecules. New viruses bud off from the host cell.

Mosquitoes pass malaria to humans through their salivary glands. Once the parasites have entered the blood stream, they go to the liver. In the liver they mature and undergo reproduction, forming merozoites. These merozoites enter the blood stream and inject themselves into red blood cells. Once inside the blood cells, they reproduce rapidly and within forty-eight to seventy-two hours, the blood cell bursts, releasing hemoglobin into the blood stream. It is the destruction of these blood cells and the hemoglobin released into the blood stream that actually causes most of the symptoms.

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.

- Microorganisms from the environment through transmission from: carriers colonized at admission, admitted to wards without undergoing surveillance, isolation or eradication of the germ(s); patients who have developed the infection but who have not been isolated;contact with contaminated objects and surfaces; medical personnel, usually via their hands; invasive procedures such as the installation or maintenance of a device(1).

Biological transmission occurs when the pathogen reproduces within a biological vector that transmits the pathogen from one host to another . Arthropods are the main vectors responsible for biological transmission. For example, hemipterans (called “kissing bugs” or “assassin bugs”) transmit Chagas disease to humans by defecating when they bite, after which the hu-man scratches or rubs the infected feces into a mucous membrane or break in the

The term virulence is one that describes the amount of damage or harm an organism does to its host. Paul Ewald, a pioneer of evolutionary biology, has discovered how virulence is tied up with the type of transmission method. There are different degrees to virulence from harmless pinworms to extremely dangerous Ebola. Ewald believes that organisms that rely on close proximity for transmission need a host that is healthy enough to be mobile. These microbes depend on the host for easy access to new hosts. This explains why people who have the cold are still able to get up and do things even though they are ill. On the opposite end of the spectrum are diseases and organisms that don’t need its host to get around. In the case of malaria it incapacitates

In the case of T. brucei, the vector is the tsetse fly. The tsetse fly resembles the common house fly with two distinguishing anatomical characteristics. While they are resting they completely fold their wings so that they rest on top of each other on top of the abdomen and they have a probe extending directly forward attached by a bulb to the bottom of the head. Today the tsetse fly is most commonly found south of the Sahara Desert in the sub-Saharan part of the country. While there are anywhere from 29 to 31 species and subspecies depending on classification, only six of them are recognized as the vector in the transmission of the parasite (1). According to The World Health Organization (WHO), vector-borne illnesses account for 17% of all infectious diseases, causing more than 1 million deaths annually (2).