Table of contents for this article

• • What is a virus
  • How does a virus spread?
  • The difference between Viruses and bacteria
  • Common viral infections

What is a virus?

Viruses are small groups of genetic code, such as DNA or RNA, enclosed within a shell of protein. A virus cannot survive or multiply on its own, nor can it obtain or store energy. It requires a living organism, or host, which it must inhabit to perform these functions that are basic to life. Hosts can be bacteria, plants, or animals,including human beings.

The incapability of a virus to survive without a host means that they are classed as non-living entities.

Some viruses, like the coronavirus SARS-CoV-2 behind COVID-19, infect the host for a number of days or weeks before being cleared from the system. Other viruses, like varicella-zoster that causes chickenpox, and the human immunodeficiency virus (HIV), can sit dormant in a host without causing an active infection for a number of years.

Read here to find out what happens when you’ve had a Covid test, from collection to results

How does a virus spread?

Most people are now aware that the SARS-CoV-2 virus can be spread through respiratory infection symptoms such as sneezing and coughing, and can also be spread through actions such as speaking or breathing.

There are four primary forms of transmission in which viruses spread:

1. Airborne transmission: Airborne transmission occurs when infected viral droplets in the air are inhaled by another living organism. Airborne transmission is how COVID-19 is commonly spread.

2. Vehicle transmission: Vehicle transmission occurs when food, water, body fluids, or inanimate objects passively carry the virus and transmit it when they come in contact with a potential host organism.

3. Direct transmission: Direct contact transmission occurs when viral particles are spread through physical contact between an infected and uninfected animal, plant, or human being. Examples include ingesting infected foodstuffs or transmission via kissing or sexual activity.

4. Indirect transmission: Indirect contact transmission occurs when the viral particles are spread via contact with contaminated materials such as unsterile medical equipment.

Difference between Viruses and bacteria

On the surface of it, viruses and bacteria may seem very similar. They are spread from human to human in very similar ways and can have similar ravaging effects on human bodies. However, there are in fact far more differences than similarities between them.

Viruses are much smaller than bacteria, and even the largest virus is tinier than the smallest bacterium.

A virus needs a living host to survive, thrive and multiply. This is not the case for bacteria, and they can live independently in almost any environment.

Treatment for bacterial infection is primarily via antibiotics. Antibiotics do not have an effect on viruses, which are generally treated with anti-viral agents where available.

Vaccines are an important preventive agent against viruses.

Common viral infections

• Coronavirus
• Influenza – causes ‘the ‘flu’
• Rhinoviruses – cause the ‘common cold’
• Human papillomavirus (HPV) – causes genital warts and cervical cancer
• Varicella-zoster – causes chickenpox
• Noroviruses – cause vomiting and diarrhoea
• Measles
• Mumps

What is the endgame of a virus?

From an evolutionary perspective, the ‘perfect’ virus is one that infects as many hosts as possible to replicate, without killing the host in the process, because the host is needed to aid transmission. The SARS-CoV-2 virus does this very well. Most infected people don’t die from the infection, and it has a relatively long incubation period, which is the time from infection to the point where symptoms are first displayed. This, and the highly effective manner in which it is transmitted through the air, make it a very successful virus.

The post What is a virus: How viruses spread, how they differ from bacteria, and common viral infections first appeared on Know Pathology Know Healthcare.

Measles is a highly contagious airborne disease that can be passed on through coughing and sneezing and can live outside the body for two hours: 90% of people coming into contact with measles are likely to contract it if they are not immunised.

The question of vaccination and immunisation looms large as a public health topic, particularly in light of recent comments by some prominent Australians.

The people who confirm if someone has contracted measles and other infectious diseases are Microbiologists like Dr Petra Derrington.

‘Early symptoms of measles include a cough, sore throat, runny nose, high fever, sore red eyes and tiredness, followed a few days later by a rash,’ said Dr Derrington.

‘While those symptoms may seem mild, 1 in 15 people infected will develop pneumonia, while 1 in 1,000 children will die from it.

‘Nearly 30% of children under 5 need hospital admission for measles. For babies, children, pregnant women and people with weakened immune systems, measles is very serious and potentially fatal.’

There are a number of measles blood tests available that can confirm whether someone has contracted the measles virus.

A measles test involves looking for the presence of the genetic material of the Paramyxoviridae virus in urine, blood or respiratory secretions.

While there is no specific treatment established for measles, a doctor may prescribe post-exposure vaccinations or immune serum globulin that when taken can dampen the symptoms and longevity of measles.

Having a test performed as quickly as possible is important as of course is the measles vaccination.

‘Measles vaccination saves lives. Measles vaccinations resulted in an 80% drop in measles deaths between 2000 and 2017, preventing an estimated 21.1 million deaths,’ said Dr Derrington.

‘Even though this safe and cost-effective vaccine is available, in 2017, there were still 110, 000 measles deaths globally, mostly among children under the age of five.’

The post Spotting viruses: how laboratories detect measles first appeared on Know Pathology Know Healthcare.

That’s welcome news, but the term eliminated can be misleading. It’s just a moment in time and in a globalised world, Australia can’t afford to rest on its laurels, but must continue to vaccinate and test for such conditions, suggests microbiologist Dr Petra Derrington:

‘There are a lot of diseases that Australians might assume have been dealt with and eliminated, but that’s not so.

‘It might surprise people to know how many conditions that we think of as in the past are very much with us today, and if not detected and treated, pose serious health risks.’

Five of the ‘old’ disease states that are still with us are:

Whooping cough

For anyone who has seen someone suffering from whooping cough, particularly a child, it is a disturbing scene. The early symptoms are similar to that of a cold, but it soon progresses to a relentless fit of coughing, followed by a whooping sound as the patient attempts to draw breath. Apnoea, where breathing stops for periods of time and the patient goes blue, is another symptom.

Whooping cough is a highly contagious respiratory infection caused by the bacterium Bordetella pertussis. It can last three months and also lead to complications like pneumonia, fits, brain inflammation, haemorrhaging and death. Detecting it as early as possible through testing in order to begin treatment and stop its spread is important, as of course is vaccination.

Syphilis

On the rise in Australia along with other Sexually Transmitted Infections (STIs) syphilis is caused by the spread of the bacterium Treponema pallidum. Many infected with syphilis may not be aware of the symptoms – which include sores on the genitals, mouth or anus and which usually self-heal.

If left untreated, syphilis can have serious health ramifications, which include joint pain, swollen lymph nodes, and neurological damage to the brain and other organs of the body depending on the stage of the condition. It is of particular concern to pregnant women.

Tuberculosis

Caused by the bacterium Mycobacterium tuberculosis, Tuberculosis is a contagious air-borne disease with symtoms including fever, chest pains, and the coughing up of blood. Those at high-risk include young children, or those with conditions that weaken the immune system, such as diabetes, cancers and HIV or AIDS.

Dengue Fever

Most commonly found in tropical locations, dengue fever is a viral infection passed on by dengue mosquitoes. It’s most common in areas of northern Queensland and can be passed on when the virus is brought in by travellers.

Symptoms include muscle and joint pain, vomiting, diarrhoea, fever, intense headache and may last up to a week. When a dengue outbreak has been reported, everyone who has symptoms and has passed through an effected area should be tested. There are four version of dengue so a blood test is required to determine the correct treatment path.

Measles

Not to be confused with the recently eradicated German Measles (aka Rubella), measles is an air-borne and potentially fatal condition that can lead to complications like pneumonia and encephalitis. While the condition is relatively rare in Australia, it’s worth reminding ourselves that on the world stage, measles is the firth highest cause of illness and death in children.

The early symptoms include fever, coughing and a runny nose. As with whooping cough, vaccination is the best insurance against measles, but a pathology test will reveal if someone has contracted the condition and the process of recovery can begin.

While these disease states have to a large degree been brought under control, thanks to Australia’s vaccination programs, they remain an ever-present danger. And while they are, pathology is critical to detecting and monitoring these conditions to ensure “herd protection”.

‘Vaccination is key, absolutely crucial to making sure we get on top, and stay on top, of these diseases which can have awful consequences.

‘But of course we know that not everyone gets vaccinated and that borders are porous: Australians travel in and out of the country all the time,’ says Dr Derrington.

‘Pathology testing therefore is absolutely critical for keeping a pulse on disease states and monitoring the health of the nation.’

The post 5 medical conditions Australia can’t shake first appeared on Know Pathology Know Healthcare.