How the world is tackling its top killers
Mercury, The (South Africa)
Infectious diseases can break |out suddenly, almost anywhere |in the world, and with devastating effects.
The past week has seen Ebola infecting key medical staff in
That was before the full extent of this year's Ebola outbreak - the worst that has been recorded - was realised.
Experts at the biennial
With mass-threat viruses dominating the headlines, we take a look at 10 of the worst communicable diseases out there - and what is being done to stop them.
The aid organisation Médecins Sans Frontières (MSF) (Doctors Without Borders) has described the Ebola outbreak in
The virus has killed 660 people |across
A growing number of health workers have also fallen victim to the disease, despite stringent requirements regarding the use of protective clothing and visors.
Ebola is transmitted through bodily fluids, and
He said: "Personal protection equipment is very hot. But there is a very strict procedure for how you wear it, how you take it off, what can be reused or not."
Local and international health workers, led in many cases by MSF and the WHO, face a combination of fear, suspicion and local traditions for burying the dead as they try to prevent Ebola spreading further.
In an update on Thursday, the WHO said efforts in the three countries "to scale up and strengthen all aspects of the outbreak response" were continuing - suggesting we are a long way from getting the better of the disease.
Last month the WHO held its sixth emergency committee meeting to discuss the international response to the Middle East Respiratory Syndrome (
While most cases are believed to involve people who have been in direct contact with camels in the
But in the most recent case, reported to the WHO by
Experts believe this adds to the growing evidence that
The WHO and the
There is a commonly held view that the bubonic plague is a matter of interest only in history books, rather than a viable threat in the present day.
A bacterial infection, it wiped out roughly half the population of
But the disease is still endemic to |the Far East, and returned to headlines this week when a Chinese town of |30 000 was placed on lockdown after |the death of a man who investigators believe handled a marmot - a small |rodent - while farming.
The quarantine has since been lifted, but it is an indication that the disease - identified as one of the world's most deadly by the WHO - is out there.
In the last decade-and-a-half there have been outbreaks all over the world, including
Because plague events are seen as a thing of the past, the WHO's epidemic disease expert, Eric Bertherat, said, they almost always led to at least some deaths.
When an outbreak occurred in
The WHO works with local medical authorities when plague outbreaks are identified, and if identified quickly bubonic plague from flea bites can be treated successfully with antibiotics.
But if it is allowed to spread to the lungs and become pneumonic plague - and passed on through saliva - patients can die within 24 hours of infection, and the mortality rate is "always very high".
H7N9 avian flu
As an example of the threat posed by avian flu viruses generally, the strand H7N9 was particularly concerning because it led patients to become "severely ill", the WHO said.
According to the agency's most |recent risk assessment on the dangers |of human infections from H7N9, at least 450 cases have been confirmed - resulting in 165 deaths.
This is all since the disease was first observed in March last year in
The WHO has warned that "much remains unknown about this virus" and expects there to be more human cases in
But because it is not thought to |pass on easily between humans, the |risk of an international spread beyond |the odd returning traveller is described |as "unlikely".
But scientists have warned that it is important people are aware of the dangers of bird flu, and the particular threat posed by each new strand that emerges.
There remains a long-standing threat from H5N1, which though rarer is fatal in two-thirds of cases.
And in February Chinese scientists said newly-discovered H10N8 had "pandemic potential".
While the WHO does not recommend limits on travel because of bird flu threats, it continues to work with the animal health sector to reduce the risk of diseases passing into local populations.
Though huge steps have been made |in research and treatment of HIV/Aids since the discovery of the virus in the 1980s, it still affects more than 35 million people worldwide and contributed to |the deaths of about 1.5 million people|last year.
The virus continues to be identified |by the WHO as a major global public health issue. The agency estimates that |it has claimed a total of 39 million lives |in 30 years.
While the effectiveness of antiretroviral drugs means people with HIV can enjoy healthy and productive lives, a cure remains elusive because of the disease's ability to incorporate itself into "reservoirs" in our DNA, beyond the reach of drugs or the immune system.
At this week's
"We are going, somehow, backwards," she said. "It's really a responsibility to put pressure on those governments which are creating such pressures to realise their responsibility, to realise the consequence of the decisions they are making. In terms of those key affected populations, but also beyond there will be consequences, and in other countries as well. As long as the virus is somewhere in the world there will be consequences."
Polio is a highly infectious disease that mainly affects children under five, and has been the subject of a huge international eradication effort since the 1988
In that time cases have reduced by |99 per cent, but the virus remains endemic in three countries -
The disease is incurable but entirely preventable using a cheap and readily-available vaccine. It invades the nervous system and can cause total paralysis in a matter of hours, with up to 10 percent of children then dying when their breathing muscles stop working.
The WHO says that "as long as a single child remains infected, children in all countries are at risk of contracting polio", and that even now a global outbreak could lead to 200 000 new cases every year within a decade.
That is why it was so concerning that 36 children in
Outbreaks typically come when civil unrest and war disrupt immunisation routines, and
A WHO spokeswoman,
YESTERDAY, the WHO marked World Hepatitis Day with a campaign to urge |the world to "think again" about a group |of infectious diseases that kill almost 1.4 million people every year.
This year the focus of World Hepatitis Day will focus particularly on Hepatitis C, one of the five strands of the virus for which there is no vaccine.
Hepatitis C affects 130 to 150 million people around the world, and up to half |a million die each year from associated liver diseases.
There is no such preventative treatment for hepatitis C, the WHO |has warned.
Issuing a statement to mark World Hepatitis Day, the UN's Office on Drugs and Crime chief
"If we fail to confront these challenges head-on, and unsafe injecting practices continue, the health risks are potentially disastrous. There are, after all, no barriers that can be built against hepatitis C, which can lay dormant creating numerous opportunities for the spread of this |silent killer."
ABOUT 84 percent of the world's children have been vaccinated against measles, and a safe and cost-effective vaccine is available globally.
Despite this, there are more than 120 000 deaths from measles every year - the equivalent of about 14 child deaths |an hour.
The WHO describes measles as a "highly contagious, serious disease", which caused 2.6 million deaths a year as recently as 1980.
It is spread by coughing and sneezing, and remains active and contagious in the air for up to two hours.
Outbreaks can happen even in the most developed countries, with 100 cases confirmed in
It is common in many developing countries, particularly in
The WHO said measles-related |deaths had reduced by 78 percent |between 2000 and 2012. The agency has collaborated with
Bacterial meningitis breaks out |in epidemics across sub-Saharan |Africa, causing a high fever, headaches and vomiting. It involves a serious infection of the lining around the brain and spinal cord, and kills up to 10 percent of patients within 24 to 48 hours of symptoms emerging.
The last epidemic, in 2009, affected |14 countries and led to more than 5 000 deaths, the biggest toll for almost 20 years.
The WHO says it hopes a new vaccine against meningitis will be provided to all 26 countries in the African meningitis belt by 2016, otherwise the pattern of epidemics and widespread deaths is likely to continue.
The agency described it as "an enormous public health burden" - one which it is committed to eliminating.
Once a disease that affected the whole world, cholera poses a threat in developing countries, disaster areas and conflict |zones today.
There are up to 5 million cases, resulting in 120 000 deaths, every year, according to the WHO.
It is described as "an extremely virulent disease" and a "global threat to public health" by the agency, and can kill within hours of drinking or using contaminated water.
There are also reports of outbreaks in
Vaccinations against cholera are available - but there remains debate |over whether the costs involved |would be better spent on improving general sanitation.
The number of reported cases of cholera has risen in recent years, and|its re-emergence as a global threat |has been described by the WHO as |"noted in parallel with the ever-|increasing size of vulnerable |populations living in unsanitary conditions". - The Independent