What are 2 types of reproductive cycles of viruses?

What are 2 types of reproductive cycles of viruses?

There are two processes used by viruses to replicate: the lytic cycle and lysogenic cycle. Some viruses reproduce using both methods, while others only use the lytic cycle.

Which RNA viruses are sexually transmitted?

Human viruses known to be spread by sexual contact include herpes simplex viruses (HSV), papillomaviruses (HPV), human immunodeficiency virus (HIV), hepatitis B virus, and cytomegalovirus. Infections with the first three (HSV, HPV, and HIV) have reached epidemic proportions and pose global health concerns.

What STD is a virus?

STIs caused by viruses include hepatitis B, herpes, HIV, and the human papilloma virus (HPV). STIs caused by bacteria include chlamydia, gonorrhea , and syphilis.

Can viruses have double-stranded DNA?

Double-stranded DNA viruses. Double-stranded DNA viruses are the most diverse and expansive of Baltimore classes. These viruses dominate the prokaryotic virome and are common in eukaryotes as well, although not to the extent of the RNA viruses.

Where is DNA in virus?

The genome of most DNA-containing viruses that infect eukaryotic cells is transported (with some associated proteins) into the cell nucleus, where the cellular DNA is, of course, also found. Once inside the cell, the viral DNA interacts with the host’s machinery for transcribing DNA into mRNA.

Is rabies a DNA virus?

Rabies is an RNA virus. The genome encodes 5 proteins designated as N, P, M, G, and L. The order and relative size of the genes in the genome are shown in the figure below. The arrangement of these proteins and the RNA genome determine the structure of the rabies virus.

Where did the polio virus come from?

1894, first outbreak of polio in epidemic form in the U.S. occurs in Vermont, with 132 cases. 1908, Karl Landsteiner and Erwin Popper identify a virus as the cause of polio by transmitting the disease to a monkey.

What year did they stop giving polio vaccine?

OPV was recommended for use in the United States for almost 40 years, from 1963 until 2000. The results have been miraculous: Polio was eliminated from the United States in 1979 and from the Western Hemisphere in 1991. Since 2000, only IPV is recommended to prevent polio in the United States.

What stopped polio?

Several key strategies have been outlined for stopping polio transmission: High infant immunization coverage with four doses of oral polio vaccine (OPV) in the first year of life in developing and endemic countries, and routine immunization with OPV and/or IPV elsewhere.

When was polio at its worst?

In the United States, the 1952 polio epidemic was the worst outbreak in the nation’s history, and is credited with heightening parents’ fears of the disease and focusing public awareness on the need for a vaccine. Of the 57,628 cases reported that year, 3,145 died and 21,269 were left with mild to disabling paralysis.

What is the key symptom of polio?

Paralysis is the most severe symptom associated with polio, because it can lead to permanent disability and death. Between 2 and 10 out of 100 people who have paralysis from poliovirus infection die, because the virus affects the muscles that help them breathe.

Is polio still around today?

The annual number of wild poliovirus cases has declined by more than 99.9% worldwide from an estimated 350,000 in 1988 when the Global Polio Eradication Initiative was launched. Of the three serotypes of wild poliovirus, type 2 was certified as eradicated in 2015 and type 3 was certified as eradicated in 2018.

Why was polio worse in the summer?

Each summer, polio would come like The Plague. Beaches and pools would close — because of the fear that the poliovirus was waterborne. Children had to say away from crowds, so they often were banned from movie theaters, bowling alleys, and the like.

How is the polio virus transmitted?

Polio is spread when the stool of an infected person is introduced into the mouth of another person through contaminated water or food (fecal-oral transmission). Oral-oral transmission by way of an infected person’s saliva may account for some cases.

How did polio spread in the 50s?

Transmitted primarily via feces but also through airborne droplets from person to person, polio took six to 20 days to incubate and remained contagious for up to two weeks after.

What was polio season?

The major outbreaks would start around Memorial Day, as the virus thrived in the heat of the summer months — this was known as “polio season.” At the time it was not known how the disease was contracted, but since the progression was so aggressive during the warmer weather, beaches and swimming pools were closed in an …

What caused polio outbreak in the 50’s UK?

An epidemic in the 1950s in the UK and beyond Did you know that Great British Bake Off’s Mary Berry contracted polio at the age of 13 and had to spend three months in hospital? This resulted in her having a twisted spine, a weaker left hand and thinner left arm.

Did adults contract polio?

The likelihood of developing paralytic polio increases with age, as does the extent of paralysis. In children, nonparalytic meningitis is the most likely consequence of CNS involvement, and paralysis occurs in only one in 1000 cases. In adults, paralysis occurs in one in 75 cases.