Q18 Which virus do you consider important?

“Which virus do you consider important?”

Because there is no set context of this topic…the key word important could mean anything in terms of a virus.

For example you can approach this essay in terms of the importance in impact of a new emerging viral epidemic that is current ie SARS and the coronavirus and how it modified global co-operation to contain the epidemic, or the importance of one that is always present has caused epidemics throughout history ie the influenza virus.

In addition, because this topic is broad it can also be answered with information with the other essay topics for example you can say HIV is important because it cannot be eradicated and with the information from q19 it can be discussed in context of its interactions with host cells. Alternatively the variole virus can be considered important because it can be an effective and potential bioweapon from the information from q 14. Also Q5 information could be use and picornaviridae family of viruses which cause the common cold is important because there are no vaccines available. You can approach this topic in context of a virus’ ability at causing disease by comparison with another pathogen for instance aswell.

I have chosen to answer this topic with rotavius because my seminar was in comparison with Vibrio cholera in terms of diarrheal diseases, and we concluded rotavirus to be more of a successful pathogen at causing disease. I believe it is also of importance because it infects mostly in children (think of the children!) and there have been current and controversial issues with the development of its vaccine. Here are reasons why I consider rotavirus to be important:

Rotavirus is the most common cause of severe diarrhea among children

Essentially every child in the US becomes infected with rotavirus and peak incidence occurs between 5 to 24 months of age.

Due to rotavirus infection, 55,000 children each year in the United States and the death of over 600,000 children annually worldwide, 80% of which occur in poorer countries.

For the distribution see:
http://www.who.int/nuvi/rotavirus/21_main_rota.jpg
http://www.who.int/immunization_monitoring/burden/rotavirus_deaths_2004_map_a.jpg
http://www.who.int/immunization_monitoring/burden/rotavirus_deaths_2004_chart_a.jpg
http://www.who.int/immunization_monitoring/burden/rotavirus_deaths_2004_map_b.jpg
http://www.who.int/immunization_monitoring/burden/rotavirus_deaths_2004_chart_b.jpg

rotavirus causes more severe diarrhea than other pathogens and accounts for a greater proportion of severe diarrhea cases à 40%-50% of diarrhea hospitalizations in the US alone.
rotavirus is responsible for more than 400,000 doctor visits; more than 200,000 emergency room visits; 55,000 to 70,000 hospitalizations; and between 20 and 60 deaths.

Rotavirus leads to about $1 billion in health care costs and lost productivity per year in the U.S.

hospitalizations of children in the U.S. with the disease have not significantly declined in the past two decades.

In developing countries, rotavirus is a major cause of childhood deaths, causing more than a half a million deaths each year in children younger than five years old.

only need 10 viral particles to establish infection because of its thick protein coat surving pH of the stomach

rotavirus kills the host cell leading to more diarrhea unlike V. cholera which leaves the epithelial cell intact. This is the reason why rotavirus causes the severe form of diarrhea compared to other pathogens

the reservoir for V. cholera and other gastroenteritis causing bacteria for example is easier to eliminate than rotavirus to prevent transmission

Rotavirus can produce spectrum of disease from asymptomatic infection to severe diarrhea

Some children will develop rotavirus gastroenteritis without a symptomatic individual as some infected individuals may be asymptomatic and shed the virus.

Children can shed rotavirus and never experience symptoms.

It is a problem to supervise and prevent kids from touching each other and washing hands properly after going to toilet etc. Unlike V. cholera, providing clean food and water to children is easier because this is usually supervised process by a parent.

rotavirus is stable in the environment and can survive several days on inanimate surfaces and therefore can be transmitted by the hands/foods more easily whilst V. cholera desiccates easily on surfaces.

Vaccines against rotavirus are available and is the single prevention and control measure with the most significant impact on reducing severe disease incidence.

In 1999, a highly efficacious rotavirus vaccine, RotaShield™, licensed in the United States, was withdrawn from the market after less than one year because of its association with intussusception.

Intussusception is a situation in which a part of the intestine has invaginated into another section of intestine, similar to the way in which the parts of a collapsible telescope slide into one another, causing obstruction.

Two new live, oral, attenuated rotavirus vaccines were licensed in 2006: the monovalent human rotavirus vaccine (Rotarix™) and the pentavalent bovine–human, reassortant vaccine (RotaTeq™).

Large safety studies with these two rotavirus vaccines have demonstrated that the vaccine is safe

Careful surveillance has not revealed any increased risk of intussusception in the vaccinated groups with either vaccines.

The new rotavirus vaccines are now introduced for routine use in a number of industrialized and developing countries.

They have been licensed in most countries and have been introduced in national immunization programs of several American countries. See: http://www.who.int/nuvi/rotavirus/24_vax_ut_rota.jpg

Several other live oral rotavirus vaccines are in various stages of development in conjunction with vaccine manufacturers in developing countries.