Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Insects implicated in the evolution of new human infectious diseases

25.10.2004


Insects and other invertebrates are the arena for the evolution of new infectious diseases in humans, new research shows.



Scientists now believe that not only are insects the carriers of some existing diseases but they are also the vehicle where recently emerging highly infectious diseases, such as the plague that killed millions in the 14th and 17th Centuries, evolve. Writing in the October edition of Nature Reviews: Microbiology, the researchers point to the large reservoir of diseases in invertebrates, such as fleas and nematode worms, which are currently harmless to humans, but which could evolve quickly into a range of new diseases.

As part of their research, Dr Nick Waterfield and Professor Richard ffrench-Constant (correct) from the University of Bath, and Professor Brendan Wren, from the London School of Hygiene and Tropical Medicine, are studying a new disease-causing (pathogenic) bacterium that has been identified in about a dozen people in the USA and Australia. Their study looked at the bioluminescent bacterium, Photorhabdus asymbiotica, which cause pustulent sores to appear on parts of sufferers¡¦ bodies. The researchers suspect that this new bacterium evolved recently from a well-known bacterium, Photorhabdus luminescens, which kills insects with the help of nematode worms.


This family of bacteria are known as Photorhabdus (glowing rods) because they are the only terrestrial bioluminescent bacteria. The bodies of insects killed by Photorhabdus luminescens infection are left luminous. Genome studies have found close similarities between the plague-causing bacterium, Yersinia pestis, and its ancestor, Yersinia psuedotuberculosis, which has been shown to be capable of causing disease insects, at least in the laboratory. Evidence suggests that the plague could have evolved from a close insect-pathogenic ancestor as little as 1,500 years ago, an eye blink in evolutionary time, suggesting that similar scenarios are possible for other insect-associated microbes.

The researchers suggest the reason that unusual infections, such as those caused by Photorhabdus asymbiotica, are not currently a large problem is that there are a range of antibiotics to treat them and insecticides that help suppress invertebrate numbers. However, they warn it could be only a short time before the parallel problems of insect resistance to insecticides and bacterial resistance to antibiotics unite to throw up new diseases that doctors will have difficulty controlling.

In-built similarities between human and insect immune systems also mean that any diseases that have successfully evolved to infect insects already have a head start if they attack people. ¡§Most scientists are looking at diseases of farm animals as the biggest threat to humans. Insects are numerous and reside in close proximity to man, yet they have been generally ignored as a potential source of microbes that could be harmful for man,¡¨ said Dr Waterfield. ¡§As well as passing microbes directly into our bloodstream when they bite us, insects can also act as a reservoir to ¡¥cook up¡¦ future human diseases.

¡§Understanding the mechanism that the bacteria use to change their disease-causing ability is important if we are to successfully treat emerging infectious diseases before they get out of control and become epidemics. ¡§There are countless species of bacteria in insects, and sometimes they cause emerging infectious diseases by becoming harmful to people ƒ{ in other words by evolving into a new type of disease which we haven¡¦t seen before. ¡§The species of bacteria may have been around for centuries, but it is just that a new strain evolves that is suddenly able to infect humans as well as other animals. ¡§The picture is further complicated by climate change, which seems to be altering the range of places insects can survive and breed, bringing new insects which can carry devastating diseases such as malaria into the Northern hemisphere.¡¨

In the case of Photorhabdus luminescens, the infection is naturally resistant to several antibiotics but the relapsing infection can be combated using repeated administration of certain drugs.

The researchers predict that the failure of automated hospital diagnostic machines to recognise this unusual bacterium means that many more cases of this new infection may exist. This is likely to be particularly true for the developing world, where doctors may diagnose the sore as a bad ulcer and treat immediately with antibiotics. Now that researchers are actively looking for Photorhabdus asymbiotica infection, they are beginning to find cases in countries in Asia.

Andrew McLaughlin | EurekAlert!
Further information:
http://www.bath.ac.uk/pr/releases/humaninfectionsfrominsects.htm
http://www.bath.ac.uk

More articles from Agricultural and Forestry Science:

nachricht Six-legged livestock -- sustainable food production
11.05.2017 | Faculty of Science - University of Copenhagen

nachricht Elephant Herpes: Super-Shedders Endanger Young Animals
04.05.2017 | Universität Zürich

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Strathclyde-led research develops world's highest gain high-power laser amplifier

The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde.

The researchers demonstrated the feasibility of using plasma to amplify short laser pulses of picojoule-level energy up to 100 millijoules, which is a 'gain'...

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

New insights into the ancestors of all complex life

29.05.2017 | Earth Sciences

New photocatalyst speeds up the conversion of carbon dioxide into chemical resources

29.05.2017 | Life Sciences

NASA's SDO sees partial eclipse in space

29.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>