We tend to just think of viruses in terms of their damaging impacts on human health and lives. The 1918 flu pandemic killed around 50 million people. Smallpox claimed 30% of those who caught it, and survivors were often scarred and blinded. More recently, we’re all too familiar with the health and economic impacts of COVID.

But viruses can also be used to benefit human health, agriculture and the environment.

Viruses are comparatively simple in structure, consisting of a piece of genetic material (RNA or DNA) enclosed in a protein coat (the capsid). Some also have an outer envelope.

Viruses get into your cells and use your cell machinery to copy themselves.
Here are six ways we’ve harnessed this for health care and pest control.

1. To correct genes

Viruses are used in some gene therapies to correct malfunctioning genes. Genes are DNA sequences that code for a particular protein required for cell function.

If we remove viral genetic material from the capsid (protein coat) we can use the space to transport a “cargo” into cells. These modified viruses are called “viral vectors”.

Viral vectors can deliver a functional gene into someone with a genetic disorder whose own gene is not working properly.

Some genetic diseases treated this way include haemophilia, sickle cell disease and beta thalassaemia.

2. Treat cancer

Viral vectors can be used to treat cancer.

Healthy people have p53, a tumour-suppressor gene. About half of cancers are associated with the loss of p53.

Replacing the damaged p53 gene using a viral vector stops the cancerous cell from replicating and tells it to suicide (apoptosis).

Viral vectors can also be used to deliver an inactive drug to a tumour, where it is then activated to kill the tumour cell.

This targeted therapy reduces the side effects otherwise seen with cytotoxic (cell-killing) drugs.

We can also use oncolytic (cancer cell-destroying) viruses to treat some types of cancer.

Tumour cells have often lost their antiviral defences. In the case of melanoma, a modified herpes simplex virus can kill rapidly dividing melanoma cells while largely leaving non-tumour cells alone.

3. Create immune responses

Viral vectors can create a protective immune response to a particular viral antigen.

One COVID vaccine uses a modified chimp adenovirus (adenoviruses cause the common cold in humans) to transport RNA coding for the SARS-CoV-2 spike protein into human cells.

The RNA is then used to make spike protein copies, which stimulate our immune cells to replicate and “remember” the spike protein.

Then, when you are exposed to SARS-CoV-2 for real, your immune system can churn out lots of antibodies and virus-killing cells very quickly to prevent or reduce the severity of infection.

4. Act as vaccines

Viruses can be modified to act directly as vaccines themselves in several ways.

We can weaken a virus (for an attenuated virus vaccine) so it doesn’t cause infection in a healthy host but can still replicate to stimulate the immune response. The chickenpox vaccine works like this.

The Salk vaccine for polio uses a whole virus that has been inactivated (so it can’t cause disease).

Others use a small part of the virus such as a capsid protein to stimulate an immune response (subunit vaccines).

An mRNA vaccine packages up viral RNA for a specific protein that will stimulate an immune response.

5. Kill bacteria

Viruses can – in limited situations in Australia – be used to treat antibiotic-resistant bacterial infections.

Bacteriophages are viruses that kill bacteria. Each type of phage usually infects a particular species of bacteria.

Unlike antibiotics – which often kill “good” bacteria along with the disease-causing ones – phage therapy leaves your normal flora (useful microbes) intact.

6. Target plant, fungal or animal pests

Viruses can be species-specific (infecting one species only) and even cell-specific (infecting one type of cell only).

This occurs because the proteins viruses use to attach to cells have a shape that binds to a specific type of cell receptor or molecule, like a specific key fits a lock.

The virus can enter the cells of all species with this receptor/molecule. For example, rabies virus can infect all mammals because we share the right receptor, and mammals have other characteristics that allow infection to occur whereas other non-mammal species don’t.

When the receptor is only found on one cell type, then the virus will infect that cell type, which may only be found in one or a limited number of species. Hepatitis B virus successfully infects liver cells primarily in humans and chimps.

We can use that property of specificity to target invasive plant species (reducing the need for chemical herbicides) and pest insects (reducing the need for chemical insecticides). Baculoviruses, for example, are used to control caterpillars.

Similarly, bacteriophages can be used to control bacterial tomato and grapevine diseases.

Other viruses reduce plant damage from fungal pests.

Myxoma virus and calicivirus reduce rabbit populations and their environmental impacts and improve agricultural production.

Just like humans can be protected against by vaccination, plants can be “immunised” against a disease-causing virus by being exposed to a milder version.

Thea van de Mortel, Professor, Nursing, School of Nursing and Midwifery, Griffith University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

While many people maintain positive emotional wellbeing as they age, around half of older Australians living in residential aged care have significant levels of depression. Symptoms such as low mood, lack of interest or pleasure in life and difficulty sleeping are common.

Rates of depression in aged care appear to be increasing, and without adequate treatment, symptoms can be enduring and significantly impair older adults’ quality of life.

But only a minority of aged care residents with depression receive services specific to the condition. Less than 3% of Australian aged care residents access Medicare-subsidised mental health services, such as consultations with a psychologist or psychiatrist, each year.

Instead, residents are typically prescribed a medication by their GP to manage their mental health, which they often take for several months or years. A recent study found six in ten Australian aged care residents take antidepressants.

While antidepressant medications may help many people, we lack robust evidence on whether they work for aged care residents with depression. Researchers have described “serious limitations of the current standard of care” in reference to the widespread use of antidepressants to treat frail older people with depression.

Given this, we wanted to find out whether psychological therapies can help manage depression in this group. These treatments address factors contributing to people’s distress and provide them with skills to manage their symptoms and improve their day-to-day lives. But to date researchers, care providers and policy makers haven’t had clear information about their effectiveness for treating depression among older people in residential aged care.

The good news is the evidence we published today suggests psychological therapies may be an effective approach for people living in aged care.

We reviewed the evidence

Our research team searched for randomised controlled trials published over the past 40 years that were designed to test the effectiveness of psychological therapies for depression among aged care residents 65 and over. We identified 19 trials from seven countries, including Australia, involving a total of 873 aged care residents with significant symptoms of depression.

The studies tested several different kinds of psychological therapies, which we classified as cognitive behavioural therapy (CBT), behaviour therapy or reminiscence therapy.

CBT involves teaching practical skills to help people re-frame negative thoughts and beliefs, while behaviour therapy aims to modify behaviour patterns by encouraging people with depression to engage in pleasurable and rewarding activities. Reminiscence therapy supports older people to reflect on positive or shared memories, and helps them find meaning in their life history.

The therapies were delivered by a range of professionals, including psychologists, social workers, occupational therapists and trainee therapists.

In these studies, psychological therapies were compared to a control group where the older people did not receive psychological therapy. In most studies, this was “usual care” – the care typically provided to aged care residents, which may include access to antidepressants, scheduled activities and help with day-to-day tasks.

In some studies psychological therapy was compared to a situation where the older people received extra social contact, such as visits from a volunteer or joining in a discussion group.

What we found

Our results showed psychological therapies may be effective in reducing symptoms of depression for older people in residential aged care, compared with usual care, with effects lasting up to six months. While we didn’t see the same effect beyond six months, only two of the studies in our review followed people for this length of time, so the data was limited.

Our findings suggest these therapies may also improve quality of life and psychological wellbeing.

Psychological therapies mostly included between two and ten sessions, so the interventions were relatively brief. This is positive in terms of the potential feasibility of delivering psychological therapies at scale. The three different therapy types all appeared to be effective, compared to usual care.

However, we found psychological therapy may not be more effective than extra social contact in reducing symptoms of depression. Older people commonly feel bored, lonely and socially isolated in aged care. The activities on offer are often inadequate to meet their needs for stimulation and interest. So identifying ways to increase meaningful engagement day-to-day could improve the mental health and wellbeing of older people in aged care.

Some limitations

Many of the studies we found were of relatively poor quality, because of small sample sizes and potential risk of bias, for example. So we need more high-quality research to increase our confidence in the findings.

Many of the studies we reviewed were also old, and important gaps remain. For example, we are yet to understand the effectiveness of psychological therapies for people from diverse cultural or linguistic backgrounds.

Separately, we need better research to evaluate the effectiveness of antidepressants among aged care residents.

What needs to happen now?

Depression should not be considered a “normal” experience at this (or any other) stage of life, and those experiencing symptoms should have equal access to a range of effective treatments. The royal commission into aged care highlighted that Australians living in aged care don’t receive enough mental health support and called for this issue to be addressed.

While there have been some efforts to provide psychological services in residential aged care, the unmet need remains very high, and much more must be done.

The focus now needs to shift to how to implement psychological therapies in aged care, by increasing the competencies of the aged care workforce, training the next generation of psychologists to work in this setting, and funding these programs in a cost-effective way.

Tanya Davison, Adjunct professor, Health & Ageing Research Group, Swinburne University of Technology and Sunil Bhar, Professor of Clinical Psychology, Swinburne University of Technology

This article is republished from The Conversation under a Creative Commons license. Read the original article.