Adenovirus Infections ~ Biology project

Introduction

What are viruses?

A virus is an infectious microbe consisting of a segment of nucleic acid (either DNA or RNA) surrounded by a protein coat. A virus cannot replicate alone; instead, it must infect cells and use components of the host cell to make copies of itself.

Discovery of the First Virus

Two scientists contributed to the discovery of the first virus, Tobacco mosaic virus. Ivanoski reported in 1892 that extracts from infected leaves were still infectious after filtration through a Chamberland filter-candle. Bacteria are retained by such filters, a new world was discovered: filterable pathogens. However, Ivanovski probably did not grasp the full meaning of his discovery. Beijerinck, in 1898, was the first to call 'virus', the incitant of the tobacco mosaic. He showed that the incitant was able to migrate in an agar gel, therefore being an infectious soluble agent, or a 'contagium vivum fluidum' and definitively not a 'contagium fixum' as would be a bacteria. Ivanovski and Beijerinck brought unequal but decisive and complementary contributions to the discovery of viruses.

Classification of virus with example

Classification based on the presence of nucleic acid

● DNA virus

Single-stranded (ss) DNA virus: e.g. Picornaviruses, Parvovirus, etc.

Double-stranded (ds) DNA virus: e.g. Adenovirus, Herpes virus, etc.

● RNA virus

Double-stranded (ds) RNA virus: e.g. Reovirus, etc.

Single-stranded (ss) RNA virus. It is further classified into two Positive sense RNA (+RNA) and negative sense RNA (-RNA). Poliovirus, Hepatitis A, Rabies virus, Influenza virus are examples of single-stranded RNA virus.

Classification based on the structure or symmetry

Complex virus. E.g Poxvirus
Radial symmetry virus. E.g.Bacteriophage
Cubical or icosahedral symmetry shaped virus. E.g. Reovirus, Picornavirus
Rod or Spiral shaped or helical symmetry virus. E.g. Paramyxovirus, orthomyxovirus

Classification based on the replication properties and site of replication

Replication within the cytoplasm of the host cell.
E.g. All RNA viruses except the Influenza virus.
Replication within the nucleus and the cytoplasm of the host cell.
E.g. Influenza virus, Poxvirus, etc.
Replication within the nucleus of the host cell.
All DNA viruses except Pox virus.
Replication of the virus through the double-stranded DNA intermediate.
E.g. All DNA viruses, Retrovirus and some tumour causing RNA virus.
Replication of the virus through a single-stranded RNA intermediate.
E.g. All RNA viruses except Reovirus and tumour-causing RNA viruses.

Classification based on the host range

Animal viruses : The influenza virus, mumps virus, rabies virus, poliovirus, Herpes virus, etc.

Plant viruses : the potato virus, tobacco mosaic virus (TMV), beet yellow virus, and turnip yellow virus, cauliflower mosaic virus, etc.

Bacteriophage : DNA virus, MV-11, RNA virus, λ page, etc.

Insect virus : Ascovirus virions and Entomopox virus, are best examples for insect virus.

Acute bronchitis ( Chest Cold)

A chest cold, often called acute bronchitis, occurs when the airways of the lungs swell and produce mucus in the lungs. That’s what makes you cough. Acute bronchitis can last less than 3 weeks.

Causes

Adenovirus usually causes acute bronchitis. Bacteria can sometimes cause acute bronchitis. But, even in these cases, taking antibiotics is NOT advised and will not help you get better.

Transmission

Viruses spread mainly from person to person by droplets produced when an ill person coughs, sneezes or talks and you inhale the droplets. Viruses may also spread through contact with an infected object. This happens when we touch something with the virus on it and then touch your mouth, eyes or nose.

Symptoms

Symptoms of acute bronchitis last less than 3 weeks and can include:

Coughing with or without mucus
Soreness in the chest
Feeling tired (fatigue)
Mild headache
Mild body aches
Sore throat

Prevention

You can help prevent acute bronchitis by doing your best to stay healthy and keep others healthy, including:

• Clean your hands.

• Get recommended vaccines, such as the flu vaccine.

• Cover your mouth and nose when coughing or sneezing.

Diagnosis

Healthcare providers can often diagnose acute bronchitis by taking a medical history and doing physical exam. Blood tests, breathing tests, and imaging tests may also be used. In most cases, antibiotics are not needed to treat acute bronchitis.

Treatment

Resting and getting plenty of fluids
Drinking lots of water, which helps loosen chest congestion
A cough suppressant and/or pain reliever
A humidifier or steam

Conjunctivitis (Pink eye)

Pink eye is an inflammation of the transparent membrane that lines the eyelid and eyeball. This membrane is called the conjunctiva. When small blood vessels in the conjunctiva become swollen and irritated, they're more visible. This is what causes the whites of the eyes to appear reddish or pink. Pink eye also is called conjunctivitis.

Causes

Several things could be to blame, including:

● Viruses, including the kind that causes the common cold

●Bacteria : Common types of bacteria that cause bacterial conjunctivitis include Staphylococcus aureus, Haemophilus influenzae, Streptococcus pneumonia and Pseudomonas aeruginosa.

●Irritants such as shampoos, dirt, smoke, and pool chlorine

●A reaction to eye drops

●An allergic reaction to things like pollen, dust, or smoke. Or it could be due to a special type of allergy that affects some people who wear contact lenses.

●Fungi, amoebas, and parasites

Transmission

The virus of Conjunctivitis usually spread from an infected person to others through:

Close personal contact, such as touching or shaking hands
The air by coughing and sneezing
Touching an object or surface with germs on it, then touching your eyes before washing your hands

Symptoms

The most common pink eye symptoms include:

Redness in one or both eyes.
Itchiness in one or both eyes.
A gritty feeling in one or both eyes.
A discharge in one or both eyes that forms a crust during the night that may prevent your eye or eyes from opening in the morning.
Tearing.
Sensitivity to light, called photophobia.

Prevention

Wash your hands often with soap and water, and help young children do the same. Wash hands especially well after touching someone with pink eye or their personal items.
Avoid touching or rubbing your eyes. This can worsen the condition or spread it to your other eye.
Avoid sharing personal items, such as makeup, eye drops, towels, bedding, contact lenses and containers, and eyeglasses.
Do not use the same eye products for your infected and non-infected eyes.
Stop wearing contact lenses until your eye doctor says it’s okay.
Clean, store, and replace your contact lenses as instructed by your eye doctor.

Diagnosis

If someone's eye is bloodshot and inflamed, they may have conjunctivitis. Conjunctivitis can have different symptoms depending on the cause. If a person has a cold and suddenly develops red eyes with little or no discomfort and clear eye discharge, it may be viral conjunctivitis. Bacterial conjunctivitis causes some eyelid swelling and thick, yellow or green eye discharge. If the eyes get red and itchy at the onset of pollen season, it is probably due to allergic conjunctivitis.

Treatment

There are times when it is important to seek medical care for conjunctivitis (pink eye). However, this is not always necessary. To help relieve some of the inflammation and dryness caused by conjunctivitis, we can use cold compresses and artificial tears, which we can purchase over the counter without a prescription. We should also stop wearing contact lenses until our eye doctor says it’s okay to start wearing them again. If we did not need to see a doctor, do not wear your contacts until you no longer have symptoms of pink eye.

Croup

Croup refers to an infection of the upper airway, which becomes narrow, making it harder to breathe. Croup also causes a cough that sounds like barking.

The cough and other signs and symptoms of croup are the result of swelling and irritation around the voice box (larynx), windpipe (trachea) and bronchial tubes (bronchi). When a cough forces air through this narrowed passageway, the swollen vocal cords produce a noise like a seal barking. Taking a breath often produces a high-pitched whistling sound called stridor.

Causes

A virus is the most common cause of croup. But the illness may also be caused by bacteria, allergies, or reflux from the stomach. Viruses that are known to cause croup are:

Parainfluenza virus
Respiratory syncytial virus (RSV)
The flu (influenza virus)
Adenovirus
Enteroviruses

Croup may occur anytime during the year, but children most often catch it in the fall or winter.

The viruses that cause croup are spread from one child to another by coughing and sneezing. They are spread through the air or from contact with the infected child's secretions. The viruses can also be spread among children by their hands, shared toys, and shared drinking glasses or spoons and forks. Children with croup are most contagious during the first few days of their illness.

Transmission

Croup is spread through direct contact with a person, or fluids from another person who has the disease. The infection starts in the nose and throat and moves into the lungs. Swelling affects the area around the voice box (larynx) and into the windpipe (trachea).

Symptoms

Croup often begins as an ordinary cold. If there's enough swelling, irritation and coughing, a child can develop:

● Loud barking cough that's made worse by crying and coughing, as well as anxiety and distress, setting up a cycle of worsening symptoms.

● Fever.

● Hoarse voice.

● Noisy or labored breathing.

● Dark, blue-tinged or pale skin

● The skin around their ribs and chest appears to be pulled in and tight, making the bones of their chest and ribs more visible

● Abnormal drowsiness and sleepiness

● An inability to drink fluids

Prevention

To prevent croup, take the same steps you use to prevent colds and flu.

Frequent hand-washing with soap and water for at least 20 seconds is the most important step.
Keep your child away from anyone who's sick.
Encourage your child to cough or sneeze into the elbow.
Clean frequently touched surfaces.

Diagnosis

A doctor can usually diagnose croup by examining the child and listening to their symptoms. But they may need tests to rule out other causes.

The child’s doctor may:

● Listen to their breathing

● Look inside their throat

● Ask about any recent illnesses or breathing problems

● Take an X-ray to check for something stuck in their throat

● Test their blood oxygen level

Treatment

Most children with mild croup symptoms can be successfully treated at home by their caregivers. Cool mist from a humidifier and/or sitting with the child in a bathroom (not in the shower) filled with steam generated by running hot water from the shower, help minimize symptoms. An adult caregiver should stay with the child during mist treatment. Engaging the child in a calming activity, such as reading a favorite book, can help decrease the child's anxiety and minimize crying, which can worsen stridor. Other suggestions for home treatment of mild croup include:

Treat fever with an antipyretic such as acetaminophen or ibuprofen.
Encourage oral intake.
Coughing can be treated with warm, clear fluids to loosen mucus in the oropharynx
Frozen juice popsicles also can be given to ease throat soreness
Avoid smoking in the home; smoke can worsen a child's cough.
Keep the child's head elevated.
At nighttime, parents/caregivers should stay in close proximity to the ill child so that they can immediately assist the child, if he or she begins to have difficulty breathing.

Pneumonia

Pneumonia is an infection that inflames the air sacs in one or both lungs. The air sacs may fill with fluid or pus (purulent material), causing cough with phlegm or pus, fever, chills, and difficulty breathing.

Causes

Pneumonia can develop when our immune system attacks an infection in the small sacs of our lung (alveoli). This causes our lungs to swell and leak fluids.

Many bacteria, viruses and fungi can cause the infections that lead to pneumonia. Bacteria are the most common cause in adults and viruses are the most common cause in school-aged children. Common illnesses that can lead to pneumonia include:

Flu viruses
Cold viruses
RSV virus (the top cause of pneumonia in babies age 1 or younger)
Bacteria called Streptococcus pneumoniae and Mycoplasma pneumoniae

Transmission

Most cases of pneumonia are caused by either bacterial or viral organisms. These can spread in a number of ways, including:

● Coughs or sneezes that aren’t covered

● Sharing cups or eating utensils

● Touching a tissue or other item after someone with bacterial or viral pneumonia has used it

● Not washing your hands regularly, especially after blowing your nose, coughing, or sneezing

Symptoms

Common pneumonia symptoms include:

Chest pain when you breathe or cough
Cough that produces phlegm or mucus
Fatigue and loss of appetite
Fever, sweating, and chills
Nausea, vomiting, and diarrhea
Shortness of breath

Along with these symptoms, older adults and people with weak immune systems might be confused or have changes in mental awareness, or they might have a lower-than-usual body temperature.

Prevention

The best way to prevent pneumonia is to get vaccinated against bacteria and viruses that commonly cause it.

In addition to getting vaccinated, you can reduce your risk of getting and spreading pneumonia with some healthy habits:

● Quit smoking and avoid secondhand smoke. Smoking damages your lungs and makes you more likely to get an infection.

● Wash your hands with soap and water before eating, before handling food and after using the restroom. If soap isn’t available, use an alcohol-based hand sanitizer.

● Avoid close contact and sharing items with other people if either of you has an infectious disease such as the flu, a cold.

● If you have to stay in a hospital or other healthcare facility, don’t be afraid to ask your providers about how to reduce your risk of getting an infection during your stay.

● Eat a healthy diet, exercise and get enough rest.

● Get treated for any other infections or health conditions you may have. These conditions could weaken your immune system, which could increase your chance of pneumonia.

Diagnosis

The Doctor will start by asking about medical history and doing a physical exam, including listening to our lungs with a stethoscope to check for abnormal bubbling or crackling sounds that suggest pneumonia.

If pneumonia is suspected, our doctor may recommend the following tests:

Blood tests. Blood tests are used to confirm an infection and to try to identify the type of organism causing the infection. However, precise identification isn't always possible.
Chest X-ray. This helps the doctor diagnose pneumonia and determine the extent and location of the infection. However, it can't tell the doctor what kind of germ is causing the pneumonia.
Pulse oximetry. This measures the oxygen level in your blood. Pneumonia can prevent our lungs from moving enough oxygen into your bloodstream.
Sputum test. A sample of fluid from our lungs (sputum) is taken after a deep cough and analyzed to help pinpoint the cause of the infection.

Treatment

Treatment depends on the type of pneumonia we have. Most of the time, pneumonia is treated at home, but severe cases may be treated in the hospital. Antibiotics are used for bacterial pneumonia. Antibiotics may also speed recovery from mycoplasma pneumonia and some special cases. Most viral pneumonias don’t have specific treatment. They usually get better on their own.

Other treatment may include eating well, increasing fluid intake, getting rest, oxygen therapy, pain medicine, fever control, and maybe cough-relief medicine if cough is severe.

CONCLUSION

Adenovirus was originally used as a vector for gene therapy. In recent years, with the development of the next-generation vectors with increased safety and high immunogenicity to transgene products, its utility as a vaccine vector has continued to increase. Adenovirus-based vaccines are currently being tested not only to prevent various infectious diseases but also to be applied as cancer vaccines.

Bibliography

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