Microbial Diseases Flashcards

Question

How does virus usually reproduce?

Answer 1

Viral nucleic acid is replicated new capsid and other structures are produced and assambled They are released when cell burst during lytic cycle and these virus particles would infect other cells

Answer 2

Polyhedral(Adenovirus) Spherical(Influenza) Helical(Tabacco mosaic virus) Complex(Bacteriophage)

Answer 3

Influenza virus Contains RNA and RNA polymerase There are 3 types, A, B and C Only A causes serious epidemics Rapid mutation therefore various strains can occur and this antigenic can lead to re-inffection Influenza is endemic, regularly epidemic and sometimes pandemic

Answer 4

Virus enter epithelial cells of nose, throat and sometimes bronchi Molecules in the outer coat of the virus bind to receptor molecules in the cell membrane of epithelial cells Inside the cell the viral coat is removed releasing the viral RNA and the enzyme RNA polymerase Viral RNA enters the host nucleus and controls protein synthesis in the cell RNA polymerase is activated and sythesises viral mRNA strands Viral proteins and lipids are formed in the cytoplasm and are assembled into viral coats Viral RNA and viral coats are assembled into new virus particles Lysis of the cell occurs and the released virus particles infect other cells

Answer 5

Trasmitted via droplet infection during coughing and sneezing Overcrouding and poor ventilation enchnce spreading

Answer 6

Incubation peridod of 2 days Headache, sore throat, backache and joint pain, fever, shivering, sweating and dry cough Usually last up to 7 days Coughing may continue due too epithelial damage to trachea and bronchi Depression may presist for some time Rarely longer than 6 days The virus attach is usually localised, but can allow secondary invasion of bacteria due to tissue damage on respiratory leading to bronchitis and pneumonia

Answer 7

Viruses are intracellular infections So very difficult to treat since drugs may not penetrate cells, and if they do, they are as likely to damage the host cells as the virus For the most part we must rely on the body's own defences Rest, aspirin to reduce temperature and plenty of fluids, can relieve the symptoms and help the body recover As with all viral diseases antibiotics are ineffective, however they may be given to treat or prevent secondary infections

Answer 8

Vaccines are available from variety of strains of the virus, annually given to maintain antibody level However only about 70% effective as antigenic variation in new strains Vaccination helps to protect particularly susceptible to reduce reseirvoir of infection Nasal sprays containing a live weakened strain for 2 to 7 years old and 2 to 17 years old at high risk Affected people should stay isolated to prevent spreading Also tissues should be used to cut the spread of droplets Ventilation and less overcrowding help also

Answer 9

Large family of virus with crown-like glycoprotein spikes They contain RNA and cause respiratory tract infection in mammals and birds Common diseases caused is usual cold, SARS, MERS and Covid-19

Answer 10

Coronaviruses are zoonotic(spread between animals with different spicies) Coronaviruses spread through close contact with people who have the virus through droplets You can catch these viruses if you breathe in these droplets or touch surfaces covered with droplets The risk of transmission is highest indoors and in crowded places

Answer 11

It attaches to epithelial cells of respiratory tract using complementary glycoproteins on cell receptor Once attached it releases RNA genome into host cell cytoplasm Coronavirus RNA genome allows it to act like a mRNA and be translated by cells ribosome to generate new viral particles Then viral particles are released from host cell by exocytosis through secretory vesicles and go to infect other cells

Answer 12

Continuous cough High temperature, fever or chills Loss of or change in, your normal sense of taste or smell Shortness of breath Unexplained tiredness, lack of energy Muscle aches or pains that are not due to exercise Not wanting to eat or not feeling hungry Headache that is unusual or longer lasting than usual Sore throat, stuffy or runny nose Diarrhoea Feeling sick or being sick

Answer 13

Assymptomatic

Answer 14

Measure of severity of disease

Answer 15

CFR = Number of deaths from diseases/ Number of deaths from disease + Number of recovered from disease * 100

Answer 16

Vaccinations Antiviral medicines Neutralising monoclonal (nMAb) treatment Treatment of symptoms by using rehydration treatments and painkillers to tackle dehydratation, pain and fever

Answer 17

Disease caused by HIV HIV is a retrovirus containing RNA and enzyme reverse transcriptase RNA and enzymes are surrounded by inner protein coat and outer protein capsid forming nucleocapsid Nucleocapsid is surrounded by a lipid envelope which contains glycoprotein spikes This enables them to attach on Helper T cells using gp120(glycoprotein)

Answer 18

Secual transmission Blood products/transfusion Sharing of needles Mother to baby via placenta, labor, breast milk

Answer 19

Virus attaches to CD4 in helper T cells by gp120 on receptor site Viral RNA and the reverse transcriptase are released into helper T cell In helper T cell viral DNA is formed using reverse trancriptase using viral RNA as template Viral DNA enters the nucleus and attaches to host DNA Viral DNA gets replicated with host DNA Viral DNA may remain inactive for up to 10 years When activaated viral DNA controls synthesis of viral protein and RNA HIV particles are assembled and helper T cell is destroyed as particles is released Virus infects other helper T cell So helper T cell decrease Immune system breaks and opportunistic infection or tumours that leads to death Common diseases are kaposi's sacroma and pneumonia

Answer 20

During first phase after infection, body produces HIV antibodies and short flu-like ilness, skin rash and swollen glands The second phase(antibody-positive phase/HIV positive phase) where no symptoms shown, may last from few weeks to 13 or more years The third phase is AIDS-related complex, variety of opportunistic diseases appear, not life threating, loss of weight and reduction of T helper cell occurs The fourth phase involves opportunistic infection organs and development of cancer and HIV wasting symptoms(dramatic weight loss) Most AIDS patients eventually die from pneumonia as immune system collapses

Answer 21

Antiretroviral therapy(ART) is used to treat HIV positive individuals on ART take a combination of HIV medicines every day ART cannot cure HIV but reduce the level of HIV in blood allowing immune system to repair to prevent HIV related diseases This will increase chances for long and healthier life Also these reduce risk of HIV trasmission as level kept low in blood HIV medicines prevents HIV from multiplying reduing amount of HIV

Answer 22

Can be classified in 4 ways: - Reverse transcription inhibitors -Protein inhibitors -Fusion and entry inhibitors -Integrase inhibitors Taking 2 or more ART is called combination therapy Combination of three or more anti-HIV drug is called Highly active antiretroviral therapy(HAART) Choice of drug to take depends on a number of factors including availability and price of drug, no of pills, side effects and other medical condition Most people living with HIV in developing world still have very limited access to drug and gets treated for opportunistic diseases and not effective for long term

Answer 23

Reduce promiscuity and safe sex by using condoms Blood screening Tissue screening Provision of clean needles for drug users to prevent sharing Caesarean section Blottle feed of babies instead of breast feed

Answer 24

Anti-HIV medication that can be taken if individual think they have been exposed to HIV For effectiveness, it should be started within 72 hours, it is only recommended to be taken if high risk explosure The quicker PEP is started the better PEP is a month-long treatment with serious side effects and not guaranteed to work This also involves taking same drugs prescribed to people who have tested positive

Answer 25

Course of HIV drugs for HIV negative indivuals at risk of being infecter Drugs are taken before sex to reduce the risk of getting HIV Results form trials are promising reducing risk of becoming positive without major side effects Available on US since 2012 and by NHS since 2016

Answer 26

By giving care and thouching victim body or fluid Handling unsterilised needles or medical equipment used Having sex with infected victims

Answer 27

The glycoproteins on the Ebola virus bind to receptors on a host cell membrane Virus then enters the cell by endocytosis On entry into the cell, the protein coat is removed and the viral RNA and RNA polymerase is released The viral RNA is replicated, transcribed and translated to produce viral RNA and proteins These are assembled to form new viruses and bud out of the cell to go on to infect other cells

Answer 28

Fever, headache, jont and muscle pain, sore throat and intense muscle weakness between 2 to 21 days after infected first Then diarrhoea, vomitting, rash, stomach pain and impared kidney and liver Bleeding internally, and maybe from ears, eyes, nose or mouth Fatal in 50 to 90 pecent of cases depending on quality of care

Answer 29

Liver cells, immune system cells, endothelial cell in blood vessels

Answer 30

Difficult to know in early stages as conventional symptoms If ebola is considered, bodily fluid would be sent to lab to be tested Suspect would be isolated to minimise contact and spreading If test is positive, patients are sent to hospital high-level isolation unit If negative, doctors will test for disease such as malaria, typhoid fever or cholera

Answer 31

Vaccines Intravenous fluids and balancing electrolytes Maintenance of oxygen status and blood pressure Treatment of other infections if happens If one cases confirmed, area should be quarantined

Answer 32

Lytic pathway resulting in lysis of prokaryotic cells

Answer 33

Enter lysogeny Here, viral DNA is incorporated into host DNA and remain dormant as not expressed Viral genome is replicated everytime host cell divides This virus is referred as provious as inactive and host cell is said to be lysogenic and capable of lysis when become active

Answer 34

Host DNA gets digested Using nucleotides from host DNA, viral DNA formed and increase in number Host cell synthesise viral phage protein from viral DNA New phages is assembled and phage enzymes causes lysis

Answer 35

Mosquito gets plasmodium from infected humans Virus reproduce in gut of female mosquito that would move into salivary glands When this feeds on humans, it would be passed into blood with anticoagulant This would multiply in liver cells They then gest into red blood cells where multiply again This causes burst releasing more

Answer 36

Fever, headache, nausea, sweating, vomiting, diarrhoea, general aches and pains Complications can occur such as severe anaemia In some cases (more severe species) the malarial parasite can accumulate in the blood vessels of the kidney causing kidney failure, or in the brain causing seizures, brain damage and coma

Answer 37

Vaccination Avoid being bitten by covering arms and legs, using insect repellent and mosquito nets Use of insecticides (spraying mosquito breeding sites and also in the production of insecticide treated bed nets) Use of antimalarial drugs, prior to and after travel, such as Atovaquone plus proguanil mefloquine (Larium) and Doxycycline

Answer 38

This is difficult due to an increase in numbers of Plasmodium resistant to drugs (e.g. chloroquine) and an increase in numbers of mosquitoes that are resistant to insecticides Previously it was difficult to produce a vaccine due to the plasmodium occupying the liver and red blood cells However, first malaria vaccine was licensed in 2021 and second roll out in 2023 The larval stages of the mosquito live in stagnant water, so draining can remove breeding sites

Answer 39

This is difficult due to an increase in numbers of Plasmodium resistant to drugs (e.g. chloroquine) and an increase in numbers of mosquitoes that are resistant to insecticides Previously it was difficult to produce a vaccine due to the plasmodium occupying the liver and red blood cells However, first malaria vaccine was licensed in 2021 and second roll out in 2023 The larval stages of the mosquito live in stagnant water, so draining can remove breeding sites

Answer 40

Feeds on another organism and causes harm

Answer 41

Lives inside host cells so avoids attack by host Antigens not exposed So production of antibodies slowed Rapidly changing surface antigens So antibodies no longer effective Hides. in red blood cells/liver So antigens cannot be detected