Microbe Mission/Diseases List

This page is for detailed information about each disease on the Microbe Mission Diseases List.

The event Microbe Mission specifies a list of diseases that may be tested on. The 2017 list may be found [[Media:Microbe Mission Diseases List 2017.pdf|here]]. Lists from past years are linked in the Resources section.

Viral Diseases
Viruses are nonliving obligate intracellular parasites that utilize either DNA or RNA as their genetic material. A virus usually has a proteinaceous capsid studded with different glycoproteins, which facilitate entry into a host cell. The capsid itself protects the genetic material of the virus.

Viruses are usually extremely species-specific, rarely infecting different species. Virus replication may be halted by antiviral medications such as aciclovir. Furthermore, vaccines, comprised of heat-killed or live attenuated viruses and/or antigens, may be injected into a host animal to provoke a humoral immune response. Antibodies produced will circulate and memory T/B cells proliferate, protecting the host from further infection.

Viruses are usually classified by the Baltimore Classification System, which separates viruses into groups by nucleic acid properties:
 * Type I viruses are double-stranded DNA viruses
 * Type II viruses are single-stranded DNA viruses
 * Type III viruses are double-stranded RNA viruses
 * Type IV viruses are positive-sense single-stranded RNA viruses
 * Type V viruses are negative-sense single-stranded RNA viruses
 * Type VI viruses are RNA retroviruses
 * Type VII viruses are DNA retroviruses

There are also several types of viruses classified by structure. Naked viruses are generally icosahedral in structure, having a capsid made of repeating protein units. Adenoviruses, which cause several foodborne diseases, are naked icosahedral viruses. Helical viruses also have a repeating capsid, but they are arranged into a helical structure. Many plant viruses, such as tobacco mosaic virus (TMV), the first virus discovered, are helical. Enveloped viruses are covered with a layer of phospholipid membrane, usually derived from their previous hosts. These viruses bud off from the membrane of animal cells. Complex viruses have a complex shape, such as bacteriophages.

AIDS
Caused by an RNA retrovirus, Human Immunodeficiency Virus (HIV), which emerged in the 1980s. HIV attacks CD4+ T-cells of the immune system, crippling its ability to defend against opportunistic infections. Several classes of retroviral medications may be given to patients, but no cure is currently available. Late-stage AIDS is marked by opportunistic infections and Kaposi's Sarcoma, a cancer caused by a human herpesvirus. AIDS is an STD, although blood transfusions and needle sharing also spreads the disease. The disease is generally diagnosed with Enzyme-Linked Immunosorbent Assay (ELISA).

Chicken Pox and Shingles
Caused by the varicella-zoster virus (VZV), a herpesvirus. Chickenpox is marked by red itchy rashes and a fever in children, and much more serious fevers in adults. However, chickenpox will not usually manifest itself twice. Shingles is more commonly seen in the elderly, and causes itchy rashes on places like the chest. Herpesviruses display lysogeny, and so shingles may recur throughout life. There exists a vaccine for VZV. The disease is spread by airborne transmission as well as from the scabs. PCR and Tzanck Smearing may be used to identify infection, and aciclovir derivatives may be used to treat the disease.

Common Cold
Caused by about 200 different types of rhinoviruses, making medication/vaccines impossible to develop. Causes symptoms of runny noses, fever, general illness that goes away after a few days. NSAIDs will usually aid in painkilling, but the recovery itself is natural. The disease is not serious in most cases.

Dengue Fever
Five types of flaviviruses, which also cause Yellow Fever. Dengue is a potentially fatal disease spread by mosquitoes. Symptoms include fever, rash, vomiting, and sores, but may also include Dengue hemorrhagic fever. The resulting low platelet count and hypotension leads to Dengue Shock Syndrome. There exists no vaccine. NSAIDs should not be used. During hemorrhaging, intravenous fluids should be administered.



Ebola Hemorrhagic Fever
Caused by one of the filoviruses, a group notorious for causing highly lethal hemorrhagic fevers. Initial fever is replaced with vomiting and diarrhea, followed by systemic organ failure and massive hemorrhaging, followed by death 1-2 weeks later. Bats are the natural vectors for the disease; the virus may also be spread by bodily fluids. Treatment includes oral rehydration. An antiviral drug has been approved for use in emergencies. The disease is endemic to sub-Saharan Africa, where mortality rates approach 90%. Poor quarantine practices in the region hamper efforts to fight the disease.

Hepatitis
Five separate viruses, collectively known as the hepatoviruses. One of the viruses is a satellite virus. The viruses affect the liver, causing fever, vomiting, pains, and potential liver failure, resulting in jaundice. In addition, infection may lead to chronic liver cirrhosis and eventually hepatocarcinoma.

Prionic Diseases
Prions are one of the two classes of nonliving pathogens. Commonly found in animal neural tissues, proteinaceous infectious agents (prions) are misfolded proteins that induce misfolding in other normal versions of itself into the prion form. Because of the subtle differences between homologous proteins of different species, prionic diseases are usually species specific, with the exception of bovine spongiform encephalopathy (BSE), which is able to spread from cattle to humans, causing Creutzfeldt-Jakob Disease (CJD). The function of normal prions are not completely understood, but it is believed they play a role in nerve bundle myelinization. Prions are especially dangerous because they are heat-stable, meaning sterilization requires extensive autoclaving and chemical degredation, which may be hard to achieve in the field. Prion diseases are fairly rare in humans, mainly passed on by genetic disorders. Prion diseases are progressively fatal, causing brain plaques that resemble Alzheimer's in postmortem autopsies. Treatment is limited, but several drugs and genetic treatments are being research.

Scrapie
This is a spongiform encephalopathy that occurs in sheep. It is so named because one of the symptoms is affected sheep scraping their fleece on rocks. Another symptom is excessive lip smacking. Because the prions don't degrade, they can easily infect other sheep. There are no cases of scrapie infecting humans, however.

Kuru
This is a unique prion disease that occurs in humans, spread by cannibalism. In the past, the Fore tribes in Papua New Guinea engaged in funerary cannibalism as part of their culture. The body is allowed to partially decompose, and then be consumed. The brain was most commonly consumed by women, resulting in a higher mortality rate among females. Funerary cannibalism is no longer performed among the Fore, but it is hard to determine whether the disease has truly been eradicated due to the long incubation period, up to 50 years. There are three stages of the disease, initially causing tremors but eventually causing loss of motor abilities and eventually death.

Parasitic Worms
Parasitic worms, known as helminths, are multicellular eukaryotes. They are split into several classes: nematodes (roundworms), platyhelminthes (flatworms), cestodes (tapeworms), and trematodes (flukes). Most helminth infections are spread by the fecal-oral route, where contaminated water containing worm spores is consumed. The worms hatch and grow in the lower GI tract, where they lay their eggs and spores. Many worms cause Neglected Tropical Diseases (NTDs), due to poor sanitation in tropical developing nations.

Anthelmintics are drugs with action against helminths. They include mebendazole, albendazole, and pyrantel palmoate. They work either by killing the worms, or paralyzing the worms, so that they drop out of the intestine in the stool. Many herbal remedies also show efficacy against helminths.

Archaea
Archaeans are not known to cause any human diseases, but because they are mentioned in most Microbe Mission tests, an introduction will be given here.

Archaea comprise of the most ancient domain of life. They are prokaryotes with distinct eukaryotic traits. Archaeans are most known for certain extremophilic members, although most archaeans are mesophilic. They have no membrane-bound organelles, being prokaryotes, but certain aspects of their genetic material replication and translation are more eukaryotic.

A more detailed description can be found in the event page: Microbe Mission

Diseases from Past Years
Information about diseases that were on previous years' lists but have since been removed. Occasionally these are tested on by inexperienced or less dedicated event supervisors who mistakenly use past lists or reuse old questions indiscriminately.

Resources

 * [[Media:Microbe Mission Diseases List 2017.pdf|2017 list]]
 * 2012 list
 * 2011 list