There are different types of microorganisms. These microorganisms may be harmless, harmful or beneficial to their hosts. Harmful ones are also called pathogenic microorganism. There microorganisms may cause kinds of communicable diseases by competing metabolic resources, destroying cells or tissues, or secreting toxins. Pathogenic microorganism may be viruses, bacteria, mycobacteria, fungi, protozoa and so on and infects people or animals in direct or indirect ways. Virus often results in serious diseases. Recent years, human have been challenged by several diseases caused by virus, such as SARS, Ebola virus, hepatitis B, HIV etc. Creative Biomart provides recombinant proteins of several sources, grades and formulations for research applications of pathogenic microorganism.
Pathogenic microorganism cause disease worldwide regardless of location, age or socio-economic status. Human infectious diseases come in many forms and span all domains of life.
Ways to contract pathogenic microorganism
The ways to contract an infectious disease are as varied as the pathogenic microorganism. Ingestion of food contaminated with Escherichia coli can lead to severe diarrhea or toxemia depending on the particular strain.
Also of concern is recently discovered prion disease where the pathogenic agent is a highly stable protein conformation. This protein can be passed from bovine to human host by ingestion of contaminated meat. After a long latency, this can develop into transmissible-spongiform encephalopathy, a lethal disease of the central nervous system.
Drinking contaminated water may also transmit disease as in the cases of Vibrio cholera, Cryptosporidium, and Giardia. These pathogens cause diarrhea and transmit from the fecal matter of infected individuals to drinking water supplies. These waterborne agents can survive for many months and remain infectious.
Infectious disease may also be airborne as in the case of influenza. Surface contact with the hands and then touching mucous membranes spreads rhinovirus, whereas polio spreads from person to person by a fecal-hand-hand route.
Transmission of pathogens microorganism may also occur from exposure to infected persons who are asymptomatic. This is the case for tuberculosis which infects approximately one in three people of whom only a small number go on to develop disease and for Staphylococcus aureus, which is an opportunistic pathogen that colonizes human skin.
While many infectious diseases have human sources, zoonotic disease arising from pathogens passed from animals to humans also represents a major mode of disease transmission. For some pathogenic microorganism, the jump from animals to humans can result in sustained human transmission as in the case for influenza, which has widespread and continued transmission after crossing the species barrier in pandemics and Ebola, which spreads among human populations locally in sporadic outbreaks. For other pathogenic microorganism, infection of humans from an animal source does not lead to transmission to other humans and represents a dead-end, such as for avian influenza (H5N1) so far and for Lassa fever virus. Still other zoonoses cycle though an animal vector such as plague, Yersina pestis, which is carried by rats, ticks and humans and malaria, Plasmodium falciparum, which is carried among humans by mosquitos.
The multiple routes of transmission of pathogenic microorganism present a complex problem to prevent their spread and no single solution has so far been discovered to prevent all microbial disease in humans.
Influence of pathogen microorganism to human
Once an infectious pathogen microorganism has transmitted to a new host, it may cause disease directly or after a prolonged period of time. Acute infections like influenza, rhinovirus and Bacillus anthracis lead to the rapid progression of symptoms usually within a few days. However, tuberculosis may persist intracellularly in the lungs of an infected person throughout their lives and HIV maintains a latent reservoir of infected CD4+ T cells even in patients treated with antiretroviral therapy. Hepatitis B and C maintain a low level of replication in liver cells and the host rarely clears chronic infections.
In addition to infection and pathogenesis, many diseases have secondary effects on their hosts. In the case of repeated diarrheal disease, this may lead to dehydration and nutritional deficiency, which in children can impair growth and cognitive development. Several pathogens increase the susceptibility to secondary infection. Most notably among these is HIV which directly impairs the host immune response and greatly increases susceptibility to opportunistic infections and tuberculosis. The pattern of multiple infections is also observed in respiratory viruses, such as influenza, where secondary bacterial pneumonia results in a more severe disease in the lower respiratory tract.
Furthermore, several viral pathogens microorganism cause little or very mild disease as a result of viral replication, but have far reaching secondary consequences unrelated to viral spread. These include human papilloma virus, HBV and HCV. Integration of HPV and HBV into the host DNA can lead to cancer. The low level of HBV and HCV replication in the liver over several years leads to chronic inflammation and sclerosis, greatly increasing the chances of developing liver cancer.
