1. The Science of Infectious Diseases
Bacterial Infections and Viral Infections

2. Bacterial Infections vs. Viral Infections
Unicellular, living organisms
Can be helpful to humans
Can be killed with antibiotic medication
Reproduce on their own - asexually
Infectious agents that can make people sick
Can Cause: fever, fatigue, and general malaise
Nonliving, do not have cells
Need a “host” organism
Always harmful
Antiviral medication will slow reproduction, but cannot destroy virus
Smaller than bacteria
Examples: tetanus, cholera, staphylococcus, STDs (syphilis, gonorrhea), tuberculosis, pneumonia, bubonic plague
Examples: common cold, chicken pox, influenza, Ebola, HIV/AIDS
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3. The Plague There are three forms of the Plague Bubonic (most common)
Septicemic
Pneumonic

4. The Bubonic Plague – the Black Death
Fatality 30% - 60% if left untreated
Transmission
Yersinia Pestis bacteria
Zoonotic bacteria – transmitted from animals (usually fleas) to humans
The bacteria enters at the bite and travels through the lymphatic system and begins replication in the nearest lymph node
Major Outbreaks
First recorded – Byzantine Empire estimated 25 – 50 million dead
Second – 1340 – 1400 Europe
Originated in China and spread to Italy and throughout Europe
Killed about 20 million
Third – mid 19th century began in Asia estimated 10 million deaths

5. The Bubonic Plague – the Black Death
Symptoms
Incubation period – 3 to 7 days
Flu-like symptoms: sudden onset fever, chills, head and body- aches and weakness, vomiting, and nausea
Bubo – the lymph nodes become inflamed, tense and painful, they can even become open sores
Treatment
Historically:
A good diet, rest, and relocation for clean air
The movement of infected patients actually caused the Plague to spread
Now:
Antibiotics and supportive therapy are effective if the patient is diagnosed in time
Isolation to stop the spread
Vaccinations have been available in the past but were not deemed effective

6. Ebola virus disease (EVD)
Fatality Rate 50% average
Fatality rates vary from outbreak to outbreak 25% to 90%
Outbreaks
Initial - villages in Central Africa as well as Sudan in 1976
Most recent - West Africa in major urban and rural areas 2014
Transmission
Human-to-human via direct contact with the blood, secretions, organs or other bodily fluids of infected people
People remain infectious as long as their blood contains the virus

7. Ebola virus disease (EVD)
Symptoms
Incubation period – the time interval from infection to onset of symptoms can be between 2 and 21 days
Humans are not infectious until symptoms develop
First symptoms: fever, fatigue, muscle pain, headache, and sore throat
Followed by: vomiting, diarrhea, rash, impaired kidney and liver function, and in some cases internal and external bleeding
Treatment
Supportive care (rehydration with oral or intravenous fluids)
Treatment of symptoms
Currently no licensed vaccines however 2 potential vaccines are undergoing human safety testing

8. HIV and AIDS Human Immunodeficiency virus Acquired Immunodeficiency Syndrome
Fatality
World-wide and estimated 39 million people have died from HIV/AIDS
An estimated 35 million people were living with HIV in 2013
3.2 million of these are children
2.1 million of these were new infections
Origination
The first recognized case of AIDS occurred in the USA in 1980s
There is still no clear answer on where HIV/AIDS came from
Scientists/doctors believe it was transmitted from Chimpanzees, as it is very similar to SIV (Simian Immunodeficiency Virus)

9. HIV and AIDS Human Immunodeficiency virus Acquired Immunodeficiency Syndrome
Transmission
HIV can be transmitted if you come into contact with the bodily fluids of an infected person
Unprotected sex
IV drug use
Child birth (although less common)
AIDS is not transmitted, it is the term used to identify late stage HIV

10. HIV and AIDS Human Immunodeficiency virus Acquired Immunodeficiency Syndrome
Symptoms
Sympotms vary from patient to patient and throughtout different stages of the virus
Stages
Early Stage –
time immediately following infection,
may experience flu-like symptoms "worst flu ever" this is the body's reaction to the infection
Clinical Latency
No symptoms
Virus slowly replicates
Still able to transmit virus to others
Progression to AIDS
The virus has weakened the immune system and patients may experience many symptoms
The symptoms may actually be caused by various opportunistic infections

11. HIV and AIDS Human Immunodeficiency virus Acquired Immunodeficiency Syndrome
Treatment
Originally doctors did not know how to treat HIV/AIDS and many people died from opportunistic infections
Today many people are living with HIV/AIDS and are managing the disease for decades
Antiviral medications can put the viral load (amount of HIV/AIDS in the blood of an infected person) to such low levels that they are undetectable
There currently is no cure and no vaccine

12. Zika virus
Fatality – people rarely die from Zika, the biggest issue is the effect it can have on an unborn child
Transmission
Through mosquito bites - Mosquitoes become infected when they feed on a person already infected with the virus. Infected mosquitoes can then spread the virus to other people through bites.
From mother to child - A pregnant woman can pass Zika virus to her fetus during pregnancy. Zika is a cause of microcephaly and other severe fetal brain defects. We are studying the full range of other potential health problems that Zika virus infection during pregnancy may cause. A pregnant woman already infected with Zika virus can pass the virus to her fetus during the pregnancy or around the time of birth.
Through sexual contact - Zika virus can be spread by a man to his sex partners. In known cases of sexual transmission, the men developed Zika virus symptoms. From these cases, we know the virus can be spread when the man has symptoms, before symptoms start and after symptoms resolve. The virus is present in semen longer than in blood.
Through blood transfusion - As of February, 1, 2016, there have not been any confirmed blood transfusion transmission cases in the United States. There have been multiple reports of blood transfusion transmission cases in Brazil. These reports are currently being investigated.
Risks -Anyone who lives in or travels to an area where Zika virus is found and has not already been infected with Zika virus can get it from mosquito bites. Once a person has been infected, he or she is likely to be protected from future infections.

13. Zika virus
Symptoms
Most people infected with Zika virus won’t even know they have the disease because they won’t have symptoms. The most common symptoms of Zika are fever, rash, joint pain, or conjunctivitis (red eyes). Other common symptoms include muscle pain and headache. The incubation period (the time from exposure to symptoms) for Zika virus disease is not known, but is likely to be a few days to a week.
See your doctor or other healthcare provider if you are pregnant and develop a fever, rash, joint pain, or red eyes within 2 weeks after traveling to a place where Zika has been reported. Be sure to tell your doctor or other healthcare provider where you traveled.
The illness is usually mild with symptoms lasting for several days to a week.
People usually don’t get sick enough to go to the hospital, and they very rarely die of Zika. For this reason, many people might not realize they have been infected.
Zika virus usually remains in the blood of an infected person for about a week but it can be found longer in some people.
Once a person has been infected, he or she is likely to be protected from future infections.

14. Zika virus
Treatment
There is no vaccine to prevent or medicine to treat Zika virus.
Treat the symptoms:
Get plenty of rest.
Drink fluids to prevent dehydration.
Take medicine such as acetaminophen (Tylenol®) or paracetamol to reduce fever and pain.
Do not take aspirin and other non-steroidal anti-inflammatory drugs (NSAIDS) until dengue can be ruled out to reduce the risk of bleeding.
If you are taking medicine for another medical condition, talk to your doctor or other healthcare provider before taking additional medication.
If you have Zika, prevent mosquito bites for the first week of your illness.
During the first week of infection, Zika virus can be found in the blood and passed from an infected person to a mosquito through mosquito bites.
An infected mosquito can then spread the virus to other people.

15. Top 5 deadliest infectious diseases – all viruses

16. Preventing Infections both bacterial and viral
Wash hands often
Cover your mouth when sneezing or coughing
Take proper care of cuts/wounds

17. Good Bacteria Not all bacteria will cause illness
Some positives of bacteria
Help with digestion
Used in wine making, backing, pickling, culturing of yogurt and cheese
Treatment of water
Fermentation of ethanol and biogas
Commercial and industrial production
Used in Science - biotechnology, genetics and molecular biology

18. Resources World Health Organization Center for Disease Control
Center for Disease Control
AIDS.gov