Microbio Module 10 Notes

Give a brief summary of the history of HIV/AIDS

• first AIDS cases in the US were reported on June 5, 1981 from five healthy homosexual young men in LA

• HIV was discovered as the causative agent of AIDS in 1982

Explain the difference between HIV and AIDS

HIV causes AIDS

Name the risk groups associated with HIV

Gay/bisexual men, drug injectors, and transgender people

Explain the five possible ways that HIV can be transmitted (transmission)

1. Sexual contact with an infected partner

2. Contact with contaminated blood/blood products

3. Sharing blood contaminated syringes and needles

4. Mother to unborn child

5. Premastication

What are the three stages of progression HIV to AIDS?

1. Acute infection

2. Clinical latency

3. AIDS

Acute infection

• occurs within 2-4 weeks of HIV infection

• Experience acute retroviral syndrome (ARS)

Clinical latency

• signs and symptoms of HIV not present

• HIV infection becomes established

AIDS

• defined as a T helper cell count of fewer than 200 per microliter of blood

• Opportunistic infections deadly to AIDS patients

6. Explain the link between HPV and cancer. What category of HPV is most associated with the development of cancer? 

HPV is the primary cause of several types of cancer, most notably cervical cancer

• most associated with high-risk

HIV incubation period

Few days to a few weeks for acute symptoms; average of 10 years for AIDS symptoms

HIV causative agent(s)

HIV causes AIDS

HIV reservoir

Humans (specifically T cells)

HIV treatment/vaccines

• antiretroviral therapy (ART)

• Multiple vaccine options being researched

HIV Stats

• in 2024: ~40.8 million people with HIV globally (1.2 million in the US)

• 20.9 million people receiving treatment (most in developing countries)

• ~44.1 million people have died from AIDS globally

HSV 1 and 2 transmission

• direct contact with herpes sores from one person to another, or one body part to another

• Asymptomatic individuals can still transmit the virus

• Mother to child via birth canal

HSV 1 and 2 Incubation period

4-10 days

HSV 1 and 2 causative agent

• HSV-1: cold sores

• HSV-2: genital herpes

HSV 1 and 2 reservoir

humans

HSV 1 and 2 treatment/vaccines

• antivirals: Zovirax, famvir, valtrex

• No vaccine

HSV 1 and 2 Stats

1 out of 6 people aged 14 to 49 infected with genital herpes

HPV transmission

Sexual contact with infected individual

HPV incubation period

1-6 months

HPV causative agent

• common warts

• Plantar warts

• Genital warts

HPV reservoir

humans

HPV treatment/vaccines

Gardasil vaccine

HPV stats

• most commonly transmitted sexual infections in the world

• US- estimated 80 million people infected with HPV

Epstein-Barr (EBV) transmission

Saliva and mucus during kissing, coughing and sneezing

Epstein-Barr (EBV) incubation period

4-6 weeks

Epstein-Barr (EBV) causative agent

Mononucleosis

Epstein-Barr (EBV) Reservoir

humans

Epstein-Barr (EBV) Treatment/vaccine

No treatment or vaccine

Epstein-Barr (EBV) stats

50 of every 100,000 Americans have symptoms of infectious mononucleosis (primarily in 15 to 30 year old age group)

Cytomegalovirus (CMV) transmission

• in utero during the first 6 months of life, exposure to mother’s genital secretions during birth, breastfeeding, oral and respiratory secretions among preschoolers

• Adults- close contact with saliva, urine, bodily fluids, sexual contact, organ transplant, blood transfusion

Cytomegalovirus (CMV) Incubation period

4-6 weeks

Cytomegalovirus (CMV) causative agent

• mononucleosis

• congenital CMV: rash, jaundice, microcephaly, low birth weight, enlarged liver and spleen, seizures, retinitis, vision loss, hearing loss, developmental and motor delay

Cytomegalovirus (CMV) Reservoir

Humans

Cytomegalovirus (CMV) Treatment/vaccines

Valcyte

Cytomegalovirus (CMV) Stats

• most common opportunistic pathogen in immunocompromised patients

• Most important cause of congenital infections

Hepatitis B transmission

• blood

• Blood-associated products

• Sexual transmission

• Mother to child

Hepatitis B Incubation period

45-180 days

Hepatitis B causative agent

Hepatitis

Hepatitis B Reservoir

Humans

Hepatitis B Treatment/vaccines

Vaccine available

Hepatitis B stats

257 million people living with chronic disease

Hepatitis C transmission

• blood

• Shared needles by IV drug users

• Mother to child

Hepatitis C incubation period

14-150 days

Hepatitis C causative agent

Hepatitis

Hepatitis C reservoir

humans

Hepatitis C treatment/vaccines

13 antivirals available for treatment

Hepatitis C stats

• 3.5 million infections in the US

• 61 million people have chronic Hep C globally

Rabies transmission

• most common mode of transmission is through bite of a rabid animal

• Rarely can be transmitted through eyes, nose and respiratory tract

Rabies incubation period

5 days to several years (average 2-3 months)

Rabies causative agent

Rabies

Rabies reservoir

zoonotic, wild mammal reservoirs

Rabies Treatment/vaccines

Post exposure prophylaxis; immunoglobulin and vaccine on day 0 followed by additional vaccine does on days 3, 7, and 14

Rabies Stats

• 55,000 deaths/year worldwide (mainly in Asia and Africa)

• 79 human cases in US in 2006, 1 to 2 deaths per year

Ebola transmission

• contact with bodily fluids of infected individual

• Sexual contact

Rabies incubation period

2-21 days

Rabies causative agent

Ebola virus disease

Rabies reservoir

Believed to be bats, but not definitively identified

Rabies Treatment/vaccines

Supportive care- balancing patients’ fluids and electrolytes, maintaining oxygen status and blood pressure, treating any complications that emerge

Rabies Stats

• sporadic outbreaks of severe infection with mortality rates

• 2014-2016 epidemic: 28, 616 cases with 11,310 deaths

Explain the significance of congenital cytomegalovirus infections.

It can lead to severe long-term disabilities

Explain the infectivity of Hepatitis B virus, as well as some of the risk factors associated with acquiring HBV. 

highly infectious, significantly more so than HIV

What is the main reservoir for rabies on the east coast of the US? 

the raccoon

When must treatment for rabies be administered? 

as soon as possible after exposure to a suspected rabid animal, before symptoms appear

What are some of the factors that lead to the Ebola epidemic of 2014-2016 outbreak to be so much worse than previous outbreaks?

• urban transmission

• Weak healthcare systems

• Cultural practices and misinformation

Zika virus transmission

• via bite of A. aegypti mosquito

• Mother to fetus

• Sexual transmission

Zika virus incubation period

3-12 days

Zika virus causative agent

zika virus disease

Zika virus reservoir

Humans and non-human primates

Zika virus treatment/vaccines

Vector control, no vaccine yet

Zika virus stats

1. Epidemic in Brazil starting in 2014:  between 440,000 and 1,300,000 ZVD cases and 5,280 suspected cases of microcephaly

2. US 2015 - 2018: 42,978 cases with 2,374 associated pregnancies (116 newborns with CZS)

Dengue virus transmission

via mosquito bite (Aedes spp.)

Dengue virus incubation period

4-7 days

Dengue virus causative agent

Dengue fever

Dengue virus reservoir

• humans

• Non-human primates (may be other animals)

Dengue virus treatment/vaccines

• vector control, supportive treatment

• Vaccine Dengvaxia

Dengue virus Stats

• 14 million people infected yearly

• 1/3 of world’s population living in areas at risk for infection

Yellow fever transmission

Via mosquito bite (Aedes or Haemogogus spp.)

Yellow fever incubation period

3-6 days

Yellow fever causative agent

Yellow fever

Yellow fever reservoir

Humans and monkeys (in jungle areas)

Yellow fever treatment/vaccines

Live attenuated viral vaccine

Yellow fever stats

• eliminated in US via mosquito control measures

• 200,000 cases with 30,000 deaths each year (90% in Africa) per CDC

West Nile transmission

transmitted to humans through the bite of an infected Culex mosquito

West Nile incubation period

2-14 days

West Nile causative agent

West Nile virus

West Nile reservoir

wild birds

West Nile treatment/vaccines

no specific antiviral treatment or approved human vaccine

Explain the correlation between climate change and the increase in arthropod-borne viral diseases. 

Climate change acts as a "threat multiplier" for arthropod-borne viral diseases

Name the five features of congenital Zika syndrome.

1. Severe microcephaly

2. Decreased brain tissue

3. Eye damage/vision impairment

4. Limited range of joint motion

5. Too much muscle tone

What is the significance of Dengue fever having more than one serotype as it correlates with the number of infections a person gets?

Dengue fever's four distinct serotypes (DENV-1–4) mean a person can be infected up to four times, with secondary infections by a different serotype being significantly more dangerous