Question

please answer questions 1-3 photos of packet provided for information

CINTOSE STUDY Part II - Viruses and Vaccines Viruses, Viruses, Viruses Smallpox, like many other dis c u s s an evil thing It has no intenso harm anyone or anything at all. Any individuals the called a virin) is that a particle, an inent object. On its own, it cant consume plants or other animals and beak them down to use the energy stored in their bonds. On its own, the virus can't crawl or fly. It can't reproduce and make more viruses. It seems as though it should be the most harmless of all the microbes, since bacteria, fungi and parasites are all free living organisms. Unlike the other microbes, a virus must have a host, even if it is an unwilling one Fach virion travels light, and like a bad guest it has to borrow things from the host tap into its power source, cade ingredients for meals appropriate some cellular wensils and hardware Some viruses are benign: they hurt no one and nothing Some are harmless to us, but deadly for other species of plant or animal. Some viruses even make their living by invading other microbes. But some do harm people, es measles, mumps, rubella, rhinovirus, rotavirus, influenza virus, human immunodeficency virus, and smallpox Without an lota of malice, a virus can destroy a life, and a viral outbreak can cripple a community or civilization. If we feel like we're sensible policy. In getting a cold or the flu, we lie down, cross our fingers, and wait for it to us, which is usually September of 1918, people all over the world did just that. But about two-thirds of those who did so died during the next ten weeks. That's about 40 million people. In some unlucky communities, like Teller, Alaska, 72 of 80 residents died in a five day period. In the United States, the type A HINI flu of 1918 killed about 675,000 people in one year I took HIV, the AIDS virus, nearly 40 years to kill about the same number of Americans. This is the story of the smallpox virus, once a terrible scourge for humanity, and now extinct. Do the Math! Viruses are everywhere. Outdoors and inside, they're part of the invisible world. Feeling a little sick, you skip school or work, and stay home. You sit in a pleasant, clean, book-filled room, in a beanbag chair, and play a video game. Your dog sleeps beside you on the carpet. A quiet day, just you and the pooch. You may think nothing else is stirring. But nothing could be farther from the truth. In fact the visions are everywhere, a veritable crowd of them: -2.5-5 x 109 virus-like particles (VLB) per liter of indoor air. In an easy, unforced inhalation, you breath in about a liter of air, so you're getting about 125.000 to 250,000 virions per breath. How many breaths per minute? How many minutes to the day? If you are indeed sick, the virus will multiply inside your cells, stealing your energy, snacking on amino acids and nibbling nucleic acids from your own cellular pantry, using all your stuff. Eventually new virions will emerge from those airway cells, and eventually you'll exhale them, or spew them out while talking or in an explosive sneeze. From the time an inhaled virion enters an airway cell until hundreds of offspring are released into the space between the cells may be as little as six hours. It takes about three to six hours for a replication round, so after about a day and several rounds of replication, the airway is chock-full of particles. Should you sneeze, cough, or even speak, you add virions to the room's bounty. Those smaller than about five microns in diameter will remain airborne until they encounter someone else's nasal mucosa. Larger particles may settle onto objects (some transmissible by touch) or to the floor. where they can be carried about on shoes and paws from room to room and may be disturbed, and once again, be come airborne. It depends on the traffic. It depends on the air in the room. Some viruses persist and are infectious for several days, others are more fragile and only last for minutes or hours outside the body. If others in the home become infected, one after another, with a few days they will each begin shedding virus at a staggered (and staggering) rate. On any given day, what sort of viruses are hanging around your house? Adenovirus, enterovirus, LAV, RSV, thinovirus, rotavirus, just to name some pathogens found in one sampled indoor environment. One virus you won't find in your home is the variola virus, which causes smallpox. The last naturally occurring case of smallpox, once a greater scourge than influenza or even plague, occurred in 1977 in Somalia. In 1980, the World Health Organization, after a massive concerted global vaccination campaign, declared the virus extinct in the wild, but a few stocks are kept in laboratories in the United States at the Centers for Disease Control (CDC) in Atlanta, Ga., and at the State Research Center of Virology and Biotechnology (VECTOR institute) in Koltsova, Russia. But if you lived in Boston in 1721, you might have millions of virions present in the common area of your home. To a resident of Massachusetts colony, the world "All Sorts of People" by Karen M. Aguirre Page 5

Answer 1

1. Volume of room = 8m × 8m × 3m

total number of students = 25

breathing rate = 30 breath per minute

Rate of virus shedding = 2 × 105 VPL per exalation

Since in 1 breath the number of VPL coming in air = 2 × 105

So, in 1 min the number of VPL in air = 30 × 2 × 105

In 1 hr the number of VPL in air = 60 × 30 × 2 × 105

                                                         = 36 × 107

Density of VPL in room = (number of viruses in room) / (volume of room)

                                         = 36 × 107 / 8 × 8 × 3

                                         = 1.875 × 106

2. total number of students inhaling = 25

Avg number of virus each student can inhale = (total number of virus in room) / 25

                                                                                 = 36 × 107 / 25

            = 1.44 107

3. No, each student will not inhale the same number of viruses. It will depend upon upon the distance of students from the infected student and also the gradient of virus across the class. The student that is sitting close to the infected student will inhale more number of VPL than the one sitting far apart. The number of viruses entering a new student will also depend upon the size of virus because if the virus size is more then it may settle down and will not spread more in the air and only the nearby students can inhale it.

No, all the students who inhaled will not be ill. Illness depends upon the number of virus entered in the body. If the threshold is not reached then the student will not be ill. But if the student has inhaled enough number of virus and he / she is immune compromised then only he will show illness. Because illness comes only if the virus starts multiplying in the host and infect more number of cell.