Lecture 15: Viruses: Novel Coronavirus HIV & AIDS: the Other Pandemic Use independently this lecture for last online assignment: Forum SARS-CoV-2 Is the Cause of COVID-19 ? A novel human coronavirus emerged in Wuhan, China in November 2019, causing severe respiratory disease in humans ? Chinese identified and sequenced the genetic material of this virus ? It is a positive-sense, enveloped RNA virus related to other coronaviruses of previous outbreaks ? SARS coronavirus (2003), the cause of Severe Acute Respiratory Syndrome, mostly confined to China and SE Asia ? MERS-CoV outbreak (2012), a severe outbreak of respiratory disease in the Middle East and South Korea CDC: Center for Disease Control and Prevention is the Primary Source of Disease Info in the Us ? According to the CDC, the novel coronavirus may cause: ? Cough ? Shortness of breath or difficulty breathing ? Or two of the following symptoms: ? Fever ? Chills ? Repeated shaking with chills ? Muscle pain ? Headache ? Sore throat ? New loss of taste or smell Characteristics of the COVID-19 Pandemic ? As of 4/2021, > 149M cases, > 3

Subject:SociologyPrice:15.89 Bought3

Share With

Lecture 15: Viruses: Novel Coronavirus HIV & AIDS: the Other Pandemic Use independently this lecture for last online assignment: Forum SARS-CoV-2 Is the Cause of COVID-19 ? A novel human coronavirus emerged in Wuhan, China in November 2019, causing severe respiratory disease in humans ? Chinese identified and sequenced the genetic material of this virus ? It is a positive-sense, enveloped RNA virus related to other coronaviruses of previous outbreaks ? SARS coronavirus (2003), the cause of Severe Acute Respiratory Syndrome, mostly confined to China and SE Asia ? MERS-CoV outbreak (2012), a severe outbreak of respiratory disease in the Middle East and South Korea CDC: Center for Disease Control and Prevention is the Primary Source of Disease Info in the Us ? According to the CDC, the novel coronavirus may cause: ? Cough ? Shortness of breath or difficulty breathing ? Or two of the following symptoms: ? Fever ? Chills ? Repeated shaking with chills ? Muscle pain ? Headache ? Sore throat ? New loss of taste or smell Characteristics of the COVID-19 Pandemic ? As of 4/2021, > 149M cases, > 3.1 M fatalities (WHO) ? In the US, > 32 M cases, > 574 K deaths (John Hopkins U.) ? Older adults and people with severe health issues more at risk ? Disease transmitted by respiratory droplets and contaminated objects ? Incubation period: 2 to 14 days ? Severe disease caused by reaction of the immune system to the presence of the virus in the body ? No specific treatment, 3 authorized vaccines in the US, many ongoing clinical trials of vaccine candidates and medicines HIV and AIDS: the Other Pandemic "In France a Skinny Man Died of a Big Disease with a Little Name“ Prince - "Sign O' the Times" ? AIDS stands for acquired immunodeficiency syndrome, first reported in the US in 1981 ?A close group of gay men fell sick of infections that were very rare in healthy population ?Soon afterwards, people that had received blood transfusions were affected by the same diseases ? HIV-1 (Human immunodeficiency virus-1) causes AIDS (1983) Global Statistics: HIV and AIDS US statistics ? More than 38 million people living with HIV globally; > 690 K died of AIDS in 2020 ? More than 32 million AIDS-related deaths worldwide since 1981 ? > 1.7 M newly-infected with HIV worldwide, > 700 K people died of AIDS in 2019 ? 19% of those infected worldwide don’t know they carry HIV ? Source: UNAIDS The Origin of AIDS ? Very recent research provides evidence that the HIV virus most likely appeared in the U.S. around 1970 ? Patient who died in 1959 in Congo is the oldest known AIDS case ? The most recent data points to Kinshasa in the Democratic Republic of Congo as the epicenter of the HIV initial expansion in humans between 1900-1930 ? A related virus, SIV, found in 36 species of non-human primates, infects but does not cause illness in monkeys ? SIV has been around for more than 1 million years ? Africa is the most likely place in which HIV first appeared HIV Jumps the Species Barrier ? HIV-1M, the pandemic form of the HIV virus, has caused >95% of all AIDS cases in the world since 1981 ? It most likely crossed to humans from chimpanzees in what is today’s Cameroon, in multiple independent events ? Monkeys are routinely consumed in Africa as food, as are other wild animals (bushmeat). SIV in chimpanzees accumulated mutations that allowed the virus to infect people handling blood and organs of monkeys, leading to the severe immunodeficiency of AIDS Structure of HIV, a Retrovirus Produces DNA using RNA as template Makes HIV a retrovirus Viral envelope made from host cell phospholipid bilayer, and viral HIV structure proteins HIV and AIDS ?HIV kills specialized white blood cells, the Thelper cells, a.k.a. CD4+ T cells ?Without these cells, the body cannot mount an effective immune response ?AIDS defined as a level of less than 200 CD4+T cells/ml of blood ?Slowly, T-helper cells are killed by HIV infection ?Host may ultimately be affected by a variety of opportunistic infections ? Tuberculosis, pneumonia, meningitis, Toxoplasma encephalitis, severe yeast infections and Kaposi’s sarcoma among many others Latent and Active HIV Infection in TH Cells Latent Active HIV Transmission ?Intimate sexual contact ?Intravenous drug use ?Blood, blood products, transfusions ?Organ transplantation ?Transplacental to the fetus, prior to birth ?During birth ?Contaminated milk from carrier mother ?Artificial insemination How HIV is NOT Transmitted ? Food or drink ? By skin contact ? By personal items of the diseased ? By kissing ? By insect bite ? By vaccines Treatment: Combination Drug Therapy and Future Vaccines Antiretroviral therapy: AZT and protease inhibitors Entry inhibitors Using an inactive strain of HIV to produce a vaccine Not yet successful No Vaccine yet to Prevent HIV Infection & AIDS ? Some of the reasons ? Mutations. The virus changes rapidly ? Many groups of HIV viruses exist ? Latent viruses. Remain hidden inside infected cells ?HIV inserts DNA originated from the virus into human chromosomes. This is called a provirus ? The antibody-producing immune system is progressively weakened ? Human-specific virus. Makes testing vaccine candidates and treatment options more difficult Preventing HIV Infection and AIDS ? Use of condoms, dental dams ? Use of sterile needles ? No needle-sharing ? Needle-exchange programs to help IV drug users ? Screening of blood and blood products ? Male circumcision ? 60% reduction of HIV infection in heterosexual contact ? Early treatment of pregnant women and newborns with antiretroviral medicines ? Only 20% of babies born to HIV-positive mothers are infected with the virus (even without treatment before birth) ? Knowledge of HIV infection by HIV testing may prevent transmission ? Antiretroviral therapy as a preventive measure to avoid HIV infection (PrEP) can be considered. Emergency post-exposure treatment is also available