Understanding Biotechnology

What is Biotechnology

Overview of Biotechnology

History of Biotechnology

Why do we do biotechnology?

Biotechnology for the environment

Biotechnology for food and agriculture

• new and previously unrecognised, such as SARS (severe acute respiratory syndrome)
• known diseases that have increased in number and spread over the past two decades, such as foot-and-mouth disease
• diseases that threaten to increase in occurrence and severity in the near future, such as influenza.

Infectious diseases pose a threat to humans, because they can pass quickly from person to person, and affect a large number of people in a very short time.

A disease-causing agent is called a pathogen and can be a virus, bacterium or a prion (a type of protein). A pathogen's ability to infect and cause disease is referred to as its pathogenicity.

A number of issues are involved in emerging infectious diseases.

• Growing tourism, trade, or political instability that results in more people and animals moving from one place to another. This can lead to a drop in standards of health or increase in the spread of infectious diseases, increasing the risk of transmitting disease from one place to another.
• The evolution of new and more deadly disease-causing pathogens. Viruses and bacteria can naturally modify their genetic material over time (mutate). Some of these changes can increase their pathogenicity, while others can allow normally harmless pathogens to transmit disease.
• Changes in climate and ecology can contribute to increases in vector-borne diseases (carried by insects). The pathogens, their vectors (the insects that transmit them) and their hosts (the animals, including humans, that can be infected by them) can all be influenced by the environment.
  • For example, mosquitoes, which carry a lot of diseases, prefer a warm climate. Global warming could increase the range of places where mosquitoes can live, allowing malaria to spread.
  • Alternatively, people are increasingly encroaching into wilderness areas to farm, as vacant land becomes scarce. This increases those people’s exposure to wild animals, many of which may harbour bacteria or viruses that do not cause disease in the animal because they have evolved together, but may cause diseases in people who have never had contact with these bacteria or viruses before.

Human behaviour also allows pathogens such as hepatitis C, HIV, SARS and variant CJD (the human form of mad cow disease) to exploit new niches.

Biotechnology is used to study the genetic material of viruses, bacteria and other organisms like prions.

Scientists can work out whether a disease is caused by a totally new pathogen, or a new type (strain) of a known pathogen. This information can be used to develop rapid diagnostic tests that enable specific detection and identification of a disease. Speedy detection of a pathogen can allow for a quick response to eradicate the disease, or to develop vaccines and effective drugs for treating infections.

Severe Acute Respiratory Syndrome (SARS)

The scientific response to the SARS outbreak was unprecedented. The World Health Organization (WHO) pulled together international teams of virologists, and within a month of the first global health alerts, the SARS pathogen was found to be a previously unidentified strain of coronavirus. A prototype diagnostic test for SARS was made available shortly afterwards.

The SARS coronavirus was identified by amplifying portions of its genetic material using polymerase chain reaction (PCR) and examining the resulting sequences.

Coronaviruses have a crown-like ‘corona’ halo of protein spikes that help them to latch on to their host cells. While many human coronaviruses cause nothing nastier than common colds, some animal coronaviruses cause more serious diseases.

The complete genome sequence of the SARS virus was published in May 2003. Analysis of this sequence indicates that the SARS coronavirus is unique. It has evolved independently from other known coronaviruses, probably within an animal host over a long period of time.

Finding the origin of the SARS virus is crucial for controlling re-emergence of the disease. A 2005 study indicated that it may have originated in bats. A molecular diagnostic test is being developed to detect the SARS infection in various animal species.

Bird flu (avian influenza)

Over the last few years, one of these fatal strains, called H5N1, devastated chicken and other poultry flocks in some parts of Asia. The outbreak hit countries such as Thailand and Vietnam hardest, as they rely on chickens for food and export.

Cambodia, Indonesia, Japan, China, South Korea, the Philippines, Europe and the United Kingdom have all reported cases of H5N1 virus infection. Japan and South Korea have been able to control these outbreaks quickly and safely.

The strain has also infected some people who have had close contact with sick birds, and has led to numerous human deaths in Thailand and Vietnam. Scientists are concerned that the virus could mutate and gain the ability to transmit from one person to another as easily as a normal ‘flu virus, which could lead to a global pandemic .

The H5N1 strain has been detected in migratory geese, which means that the disease could be spread when the birds travel during change of seasons. The World Health Organization (WHO) predicts that India could be at greatest risk from these birds. The WHO is also encouraging changes to farming practices and marketing of live animals, to reduce the risk of the H5N1 strain to humans.

In 2005, initial clinical trials showed that an experimental H5N1 vaccine evoked an immune response in humans. Several different H5N1 vaccines are currently under development around the world. Once a safe vaccine is available, the WHO plans on creating a global stockpile of up to 50 million doses.

Any researchers studying the H5N1 virus wear special biocontainment suits to prevent infection, and work in certified biocontainment laborator ies with strict controls against infection.