Mic 541 Exam 4 - Virology - Slides 100-150

Significant factor in spread to heterosexual population.

genus Lentivirus - other human retroviruses = T-cell lymphotropic viruses I and II, leukemia and lymphoma.

Persons who may have been exposed should be tested a second time 3-6 months later.

Transmitted by respiratory aerosols.

Non-nucleoside inhibitors (NNIs) are a class of antiretroviral drugs that interact with and inhibit reverse transcriptase (RT), an enzyme crucial for the replication of the HIV virus. Unlike nucleoside inhibitors (NIs), NNIs do not function as nucleoside analogs. Instead, they bind to a different site on the RT enzyme, causing a conformational change that prevents the enzyme from functioning properly. This inhibition of RT activity helps to suppress viral replication and slow down the progression of HIV infection.

Efficacy ranges from 60-90%. Older adults = 50-60%. Nursing homes = 20-45%.

Controlling the vector, which refers to the organism that transmits the virus, is an effective way to control the spread of arboviruses. Arboviruses are primarily transmitted to humans through the bites of infected mosquitoes, ticks, or other vectors. By implementing measures to control these vectors, such as using insecticides, eliminating breeding sites, and implementing personal protective measures, the transmission of arboviruses can be significantly reduced. Therefore, the statement "With regard to arboviruses, controlling the vector controls the disease" is true.

The set of diseases caused by Arenaviruses includes Lassa fever, Argentine hemorrhagic fever, Bolivian hemorrhagic fever, and Lympthocytic choriomeningitis.

Testing based on detection of antibodies specific to the virus in serum or other fluids; done at 2 levels. Initial screening - ELISA, latex agglutination, and rapid antibody tests (rapid results but may result in false positives). Follow up with Western blot analysis to rule out false positives.

The correct answer is the Furious phase. This phase of rabies is characterized by symptoms such as agitation, disorientation, seizures, twitching, and hydrophobia. During this phase, the infected individual may exhibit aggressive behavior, become hypersensitive to stimuli, and have difficulty swallowing due to muscle spasms in the throat. These symptoms are a result of the virus affecting the central nervous system.

Relatively large RNA viruses with distinctively spaced spikes on their envelopes.

M2 ion channel blockers - effective against influenza A but not B and C.

Different from German measles. The Measles Virus is also known as red measles and rubeola.

Retroviruses are enveloped viruses, meaning they have a lipid membrane surrounding their protein coat. This membrane is derived from the host cell's plasma membrane as the virus buds out of the cell during the replication process. The envelope plays a crucial role in the virus's ability to infect host cells and evade the immune system.

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The prodromal phase of rabies is characterized by symptoms such as fever, nausea, vomiting, headache, and fatigue. Some individuals may also experience pain, burning, and tingling sensations at the site of the wound. This phase occurs before the onset of the more severe symptoms associated with the furious or dumb phases of rabies.

Rubella is commonly known as German measles. It is a contagious viral infection that causes a rash and fever. The term "German measles" is used to differentiate it from regular measles, which is caused by a different virus. Rubella is characterized by a mild illness, but it can be dangerous for pregnant women as it can cause birth defects.

HIV can remain asymptomatic for a period of 2-15 years. During this time, individuals infected with HIV may not exhibit any visible symptoms of the infection. However, it is important to note that even in the absence of symptoms, the virus is still active and can be transmitted to others. Regular testing and early diagnosis are crucial in order to manage the infection effectively and prevent its spread.

California encephalitis, Rift Valley fever, Korean hemorrhagic fever, and Hantavirus cardiopulmonary syndrome are all diseases caused by Bunyaviruses. Bunyaviruses are a group of RNA viruses that are transmitted to humans through arthropod vectors such as mosquitoes and ticks. These viruses can cause a range of symptoms including fever, encephalitis, hemorrhagic fever, and respiratory distress. Therefore, the set of diseases listed in the answer are all caused by Bunyaviruses.

The correct answer is Family = Rhabdovirus, Genus = Lyssavirus. This means that Rabies belongs to the Rhabdovirus family and the Lyssavirus genus. The family classification is higher than the genus classification, so it is more specific. In this case, Rhabdovirus is the family to which Lyssavirus belongs, making it the correct answer.

HIV cannot survive for extended periods of time outside the body. The virus is very fragile and cannot survive for long outside of a host. It requires a specific environment with the right temperature, moisture, and pH levels to remain viable. Once outside the body, the virus quickly becomes inactive and unable to infect new cells. Therefore, the statement that HIV can survive for extended periods of time outside the body is false.

The correct answer is A = Urban cycle, B = Sylvan cycle. This means that humans and mosquitoes are properly matched with the urban cycle, while forest monkeys and mosquitoes are properly matched with the sylvan cycle. This suggests that humans and mosquitoes are more likely to be involved in transmission in urban areas, while forest monkeys and mosquitoes are more likely to be involved in transmission in forested areas.

T-cell numbers, specifically CD4+ T-cells, play a crucial role in the immune system's ability to fight off infections. In the later phases of HIV disease and full-blown AIDS, the virus has significantly damaged the immune system, leading to a decline in T-cell numbers. However, in the earlier stages of HIV, T-cell numbers may still be relatively normal. Therefore, the statement that T-cell numbers remain relatively normal until the later phases of HIV disease and full-blown AIDS is true.

The correct answer is from men to women. This is because during vaginal sex, the virus can enter the woman's bloodstream through small tears or abrasions in the vaginal lining, making it easier for HIV to be transmitted from an infected man to an uninfected woman. However, it is important to note that HIV can also be transmitted from women to men during vaginal sex, although the transmission rate is generally lower.

Nucleoside inhibitors (NIs) are antiretroviral drugs that are analogs incorporated by reverse transcriptase (RT) and block elongation. The first anti-HIV drug, AZT, belongs to this class. NIs work by inhibiting the replication of the virus by interfering with the reverse transcription process. They act as false building blocks, preventing the virus from synthesizing its genetic material correctly. This ultimately leads to the inhibition of viral replication and the control of HIV infection.

The goal of treatment for H1N1 is to control the symptoms. This means that the focus is on managing and alleviating the symptoms experienced by the patient, rather than completely eradicating the disease or curing the patient. Treatment options for H1N1 typically include rest, fluids, over-the-counter medications for symptom relief, and in some cases, antiviral medications. By controlling the symptoms, the patient's discomfort can be minimized, and their recovery can be facilitated.

Complications include: sore throat, dry cough, headache, conjunctivitis, lymphadenitis, fever, Koplik spots (oral lesions). Most serious complication is subacute sclerosing panencephalitis (SSPE), a progressive neurological degneration of the cerebral cortex, white matter, and brain stem.

Treatment with interferon and ribavirin to lessen liver damage; no cure. No vaccine.

However, outbreaks still occur among groups that refuse vaccination.

Babies can be infected before or during birth and from breast feeding.

Rabies virions are enveloped, bullet-shaped particles. This means that they have a lipid envelope surrounding their nucleocapsid, which gives them a rounded shape with pointed ends resembling a bullet. The envelope is derived from the host cell membrane and contains viral glycoproteins that are important for attachment and entry into host cells. The bullet shape is characteristic of the rabies virus and is often used to identify it under electron microscopy.

Blood transfusions, needle sharing by drug abusers.

The correct answer is A = parainfluenza, B = measles virus, C = respiratory syncytia virus. This is because parainfluenza is caused by paramyxoviruses, measles virus is a type of morbillivirus, and respiratory syncytia virus is a type of pneumovirus.

The correct answer is "Dumb phase." The description provided in the question matches the symptoms of the dumb phase of clinical rabies. During this phase, the individual may experience paralysis, disorientation, and stupor, which can progress to a coma and eventually lead to death. The dumb phase is characterized by a lack of the characteristic aggressive and hyperactive behavior seen in the furious phase of rabies.

The major site of HIV replication is in the lymph nodes. Lymph nodes are small, bean-shaped organs that are part of the immune system. They are located throughout the body and play a crucial role in filtering and trapping foreign substances, including viruses like HIV. HIV primarily infects and replicates in immune cells called CD4 T cells, which are abundant in the lymph nodes. Therefore, the lymph nodes serve as a major reservoir for HIV replication and contribute to the spread of the virus throughout the body.

After exposure to HIV, antibodies typically appear in the serum within 1 month. This is known as the seroconversion period, during which the immune system produces antibodies to fight against the virus. It is important to note that this timeline can vary slightly from person to person, but on average, antibodies can be detected within a month of exposure.

Widespread as influenza but more benign, respiratory transmission, seen mostly in children, minor cold, bronchitis, bronchopneumonia, croup, no specific treatment available; supportive therapy.

Infuse the would with human rabies immune globulin (HRIG) and globulin; vaccination with human diploid cell vaccine (HDCV), an INactivated vaccine given in 6 doses with 2 boosters.

HIV can only infect host cells that have the required CD4 marker plus a coreceptor.

Zanamivir is administered nasally, meaning it is inhaled through the nose. On the other hand, oseltamivir is administered orally, which means it is taken by mouth.

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Amantadine, rimantadine, zanamivir, and oseltamivir are possible medications for controlling the symptoms of H1N1. These medications are antiviral drugs that can help reduce the severity and duration of symptoms caused by the H1N1 virus. Amantadine and rimantadine are antiviral drugs that specifically target influenza A viruses, including H1N1. Zanamivir and oseltamivir are neuraminidase inhibitors that can be used to treat both influenza A and B viruses, including H1N1. These medications work by inhibiting the replication of the virus and can be effective in reducing the symptoms and complications associated with H1N1 infection.

The correct answer is amantadine and rimantadine. These two drugs, known as adamantanes, were previously used to treat and control symptoms of the flu virus. However, over time, the flu virus has developed a high rate of resistance to these drugs, rendering them less effective. As a result, they are no longer recommended for the treatment of flu.

Epidemic parotitis; self-limited, associated with painful swelling of parotid salivary glands, humans are the only reservoir, 40% of infections are subclinical; long-term immunity, 300 cases in US/year, incubation 2-3 weeks fever, muscle pain and malaise, classic swelling of one or both cheeks, usually uncomplicated invasion of other organs; in 20-30% of infected adult males, epididymis and testes become infected; sterility is rare, symptomatic treatment, live attenuated vaccine MMR.

Reverse transcription - high error rate = rapid evolution, RT>RNA pol > DNA pol. Integration into host genome - markers of evolution, insertional activation of oncogenes, gene delivery vectors.

The correct answer includes the components of flu vaccines that are commonly used. Influenza A subtype - H1N1, influenza A subtype H3N2, and influenza B virus are all strains of the influenza virus that are known to cause illness in humans. These strains are included in flu vaccines to provide protection against the most common and potentially dangerous types of influenza. Influenza C subtype - H1N1 and influenza E virus are not commonly included in flu vaccines as they are less common and less likely to cause severe illness.

The correct answer is "less than 100" because the question asks for the number of cases of Measles Virus seen in the US each year. Since the answer options are in decreasing order, the option "less than 100" is the most appropriate choice as it indicates a smaller number of cases compared to the other options.

Hemorrhagic fevers are characterized by various symptoms including acute fever, headache, muscle pain, oral hemorrhage, jaundice, liver and kidney damage, and even death. These symptoms are commonly observed in individuals affected by hemorrhagic fevers.

The HIV reverse transcriptase enzyme serves two purposes. First, it makes a double stranded DNA from the single-stranded RNA genome of the virus. This is a crucial step in the replication of the virus. Second, it permanently integrates the viral genes into the host DNA. This allows the virus to become a part of the host's genetic material and ensures its persistence within the host's cells.

Humans can serve as dead-ends or accidental hosts in the arbovirus life cycle, meaning that they can become infected with the virus but do not contribute to its transmission. This can occur when a mosquito or other arthropod vector bites an infected human and then bites another susceptible host, thus passing on the virus. Humans can also serve as maintenance reservoirs, meaning that they can harbor the virus and transmit it to other susceptible hosts over an extended period of time, contributing to the persistence and spread of the virus in the population.