Microbe of the Month: The microbiologist as Pied Piper: Bernard Dixon on the strange and sometimes lethal hantaviruses, which spread to humans from rodents

However fascinating it may be as a scholarly achievement, there is virtually nothing that has come from molecular biology that can be of any value to human living in the conventional sense of what is good, and quite tremendous possibilities of evil.

Those words, from the Nobel prize- winner Sir MacFarlane Burnet, were published in his autobiography only 25 years ago. Yet they can already be consigned to the dustbin of history, alongside the assurance by astronomer royal Sir Richard Woolley in 1956 that space travel was 'utter bilge'. A quarter of a century after Burnet's surprising gaffe, scarcely a week goes by without the announcement of some application of the science whose practical significance he derided.

One wonders what the Australian immunologist would make of developments such as the identification of genes predisposing individuals to inherited diseases, the genetic engineering of pest-resistant crops, and the retrieval of DNA from the tissues of extinct animals.

One advance of which he would surely approve is the dramatic transformation in scientists' tools for investigating infectious diseases. Typical is a mysterious and lethal form of pneumonia that appeared in New Mexico last May. Six months later, scientists at the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, have identified the virus responsible by using molecular biology to demonstrate its kinship with one that causes a milder disease in Europe. These and other members of the same family are called hantaviruses, after the Hantaan River in South Korea where yet another family member, Hantaan virus, caused fevers and deaths among troops serving in the Korean war.

Research in Atlanta has now revealed the close relationship between eight known hantaviruses, which are carried by rats, mice and other small rodents and in most cases can be transmitted to humans. The technique used to demonstrate this kinship is called the polymerase chain reaction (PCR), which amplifies tiny quantities of DNA. Although the CDC researchers investigating the New Mexico incident did not originally know what microbe they were dealing with, they applied this method to amplify DNA from the tissues of dead victims. They were thus able to compare the DNA with that of other, familiar microbes. They found that it resembled two other hantaviruses, including Puumala virus, which occurs in Scandinavia and elsewhere in Europe.

The New Mexico virus came to light when a young man died in hospital a few days after attending the funeral of his fiancee. Both had succumbed to sudden, acute chest infection. At least 40 others were attacked by the same virus, now known to be transmitted by deer mice, and 26 of them have died. The other hantaviruses affecting humans produce a condition known as haemorrhagic fever with renal syndrome (HFRS), characterised by haemorrhages and kidney failure. Despite these effects, HFRS is significantly less lethal. Hantaan virus killed 7 per cent of its victims during the Korean war, while Puumala virus has mortality of less than 1 per cent.

Recent recognition of the relationship between the hantaviruses, facilitated by PCR, has coincided with an increasing realisation that they pose a threat to human health in many parts of the world and certainly whenever infected rodents are in contact with humans. The virus appears to be transmitted by aerosol from the animals' urine and faeces.

Any increase in the size of an infected rodent population almost inevitably triggers a rise in human infections. The New Mexico outbreak has been traced to a population explosion in deer mice, caused in turn by an abundance of pine nuts and grasshoppers after heavy snows disturbed the ecology of the deserts and mountains last spring. Dr Peter Kulzer, of the University of Wurzburg, writing recently in the Lancet, reported 40 cases of HFRS in Germany in the first half of 1993 - an unusually large number - which he suggests is related to a proliferation of small rodents.

There is little firm information about hantavirus infections in Britain. There were two cases in Scotland during the 1980s and earlier this year scientists at the public health laboratory in Taunton reported an acute illness in 29 patients with antibodies indicating that they had been infected with hantavirus. The most severely infected individuals developed a high fever, swelling of the face, neck and extremities, malaise lasting for months, and a tendency to haemorrhage. Many of the patients worked in rat-infested areas, and research is now in progress to determine what proportion of rodents in Somerset carry hantavirus.

Worldwide, an estimated 200,000 people are infected with a hantavirus each year, and between 4,000 and 20,000 of them die as a result. With virtually no treatment yet available, the best hope of reducing this toll, and of combating future outbreaks, rests on the development and application of vaccination - which, in turn, requires better definition of high-risk groups and the geography of the infection. And that, despite Sir MacFarlane Burnet's gloomy prognostication, means more applied molecular biology.

Suggested Topics
News
people
News
people And here is why...
News
peopleStella McCartney apologises over controversial Instagram picture
Life and Style
Laid bare: the Good2Go app ensures people have a chance to make their intentions clear about having sex
techCould Good2Go end disputes about sexual consent - without being a passion-killer?
PROMOTED VIDEO
Arts and Entertainment
Richard Burr remains the baker to beat on the Great British Bake Off
tvRichard remains the baker to beat as Chetna begins to flake
News
i100
Sport
footballArsenal 4 Galatasaray 1: Wenger celebrates 18th anniversary in style
Arts and Entertainment
Amazon has added a cautionary warning to Tom and Jerry cartoons on its streaming service
tv
News
people
News
The village was originally named Llansanffraid-ym-Mechain after the Celtic female Saint Brigit, but the name was changed 150 years ago to Llansantffraid – a decision which suggests the incorrect gender of the saint
newsWelsh town changes its name, but can you spot the difference?
News
ebooksAn unforgettable anthology of contemporary reportage
Arts and Entertainment
Kristen Scott Thomas in Electra at the Old Vic
theatreReview: Kristin Scott Thomas is magnificent in a five-star performance of ‘Electra’
News
Destructive discourse: Jewish boys look at anti-Semitic graffiti sprayed on to the walls of the synagogue in March 2006, near Tel Aviv
peopleAt the start of Yom Kippur and with anti-Semitism flourishing, one Jew can no longer ignore his identity
Life and Style
Couples who boast about their relationship have been condemned as the most annoying Facebook users
tech
Arts and Entertainment
Hayley Williams performs with Paramore in New York
musicParamore singer says 'Steal Your Girl' is itself stolen from a New Found Glory hit
News
i100
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Associate Recrutiment Consultant

£18000 - £23000 per annum + Uncapped OTE: SThree: SThree Group have been well ...

Trainee Recruitment Consultant

£18000 - £23000 per annum + OTE: SThree: Real Staffing Group is seeking Traine...

Year 6 Teacher (interventions)

£120 - £140 per day: Randstad Education Leeds: We have an exciting opportunity...

PMLD Teacher

Competitive: Randstad Education Manchester: SEN Teacher urgently required for ...

Day In a Page

Italian couples fake UK divorce scam on an ‘industrial scale’

Welcome to Maidenhead, the divorce capital of... Italy

A look at the the legal tourists who exploited our liberal dissolution rules
Time to stop running: At the start of Yom Kippur and with anti-Semitism flourishing, one Jew can no longer ignore his identity

Time to stop running

At the start of Yom Kippur and with anti-Semitism flourishing, one Jew can no longer ignore his identity
Tom and Jerry cartoons now carry a 'racial prejudice' warning on Amazon

Tom and Jerry cartoons now carry a 'racial prejudice' warning on Amazon

The vintage series has often been criticised for racial stereotyping
An app for the amorous: Could Good2Go end disputes about sexual consent - without being a passion-killer?

An app for the amorous

Could Good2Go end disputes about sexual consent - without being a passion-killer?
Llansanffraid is now Llansantffraid. Welsh town changes its name, but can you spot the difference?

Llansanffraid is now Llansantffraid

Welsh town changes its name, but can you spot the difference?
Charlotte Riley: At the peak of her powers

Charlotte Riley: At the peak of her powers

After a few early missteps with Chekhov, her acting career has taken her to Hollywood. Next up is a role in the BBC’s gangster drama ‘Peaky Blinders’
She's having a laugh: Britain's female comedians have never had it so good

She's having a laugh

Britain's female comedians have never had it so good, says stand-up Natalie Haynes
Sistine Chapel to ‘sing’ with new LED lights designed to bring Michelangelo’s masterpiece out of the shadows

Let there be light

Sistine Chapel to ‘sing’ with new LEDs designed to bring Michelangelo’s masterpiece out of the shadows
Great British Bake Off, semi-final, review: Richard remains the baker to beat

Tensions rise in Bake Off's pastry week

Richard remains the baker to beat as Chetna begins to flake
Paris Fashion Week, spring/summer 2015: Time travel fashion at Louis Vuitton in Paris

A look to the future

It's time travel fashion at Louis Vuitton in Paris
The 10 best bedspreads

The 10 best bedspreads

Before you up the tog count on your duvet, add an extra layer and a room-changing piece to your bed this autumn
Arsenal vs Galatasaray: Five things we learnt from the Emirates

Arsenal vs Galatasaray

Five things we learnt from the Gunners' Champions League victory at the Emirates
Stuart Lancaster’s long-term deal makes sense – a rarity for a decision taken by the RFU

Lancaster’s long-term deal makes sense – a rarity for a decision taken by the RFU

This deal gives England a head-start to prepare for 2019 World Cup, says Chris Hewett
Ebola outbreak: The children orphaned by the virus – then rejected by surviving relatives over fear of infection

The children orphaned by Ebola...

... then rejected by surviving relatives over fear of infection
Pride: Are censors pandering to homophobia?

Are censors pandering to homophobia?

US film censors have ruled 'Pride' unfit for under-16s, though it contains no sex or violence