The host-pathogen interaction is defined as how microbes or viruses sustain themselves within host organisms on a molecular, cellular, organismal or population level.
Viruses can also infect the host with virulent DNA, which can affect normal cell processes (transcription, translation, etc.
Giardia lamblia was discovered by Leeuwenhoeck in the 1600s[2][3] but was not found to be pathogenic until the 1970s, when an EPA-sponsored symposium was held following a large outbreak in Oregon involving the parasite.
Since then, many other organisms have been identified as pathogens, such as H. pylori and E. coli, which have allowed scientists to develop antibiotics to combat these harmful microorganisms.
Many pathogenic bacteria, such as food-borne Staphylococcus aureus and Clostridium botulinum, secrete toxins into the host to cause symptoms.
Aspergillus the most common pathogenic fungi, secretes aflatoxin, which acts as a carcinogen and contaminates many foods, especially those grown underground (nuts, potatoes, etc.).
Microbes and fungi cause symptoms due to their high rate of reproduction and tissue invasion.
This causes an immune response, resulting in common symptoms as phagocytes break down the bacteria within the host.
The lysogenic cycle, however, is when the viral DNA is incorporated into the host genome, allowing it to go unnoticed by the immune system.
Eventually, it gets reactivated and enters the lytic cycle, giving it an indefinite "shelf life" so to speak.
[13] Dual-species proteomics could also be employed to study host-pathogen interactions by simultaneously quantifying proteins newly synthesized by the host and pathogen.
[16] However, in order to cope with the changing pathogenic environment, treatment methods need to be revised to deal with drug-resistant microbes.