Plague outbreak: where does it still exist and could it spread?



File 20171115 19799 1g1ck15.jpg?ixlib=rb 1.1
Plague still exists in wild rodents and eradication probably isn’t possible.
from http://www.shutterstock.com

Allen Cheng, Monash University

An outbreak of plague has been occurring in Madagascar, with more than 2,000 cases and 170 deaths reported since August 2017.

This island nation is one of the few remaining hotspots for plague in the world, with cases usually reported between September and April each year.

But this outbreak has been unusual, as it has affected many different areas in Madagascar, including heavily populated cities.

What is plague, and how is it treated?

Plague is a serious disease caused by the bacteria Yersina pestis. It has a high death rate if untreated. There are several different clinical forms, including bubonic plague (affecting the lymph nodes), pneumonic plague (affecting the lungs) and septicaemic plague (involving the bloodstream).

Outside of outbreak situations, deaths from plague are usually due to delays in recognition and diagnosis, rather than a lack of treatment options. Although antibiotic resistant strains have been described, plague can generally be treated with a number of commonly available antibiotics.

Why does plague still exist?

Plague was responsible for hundreds of millions of deaths in three devastating pandemics, including the Plague of Justinian in the 6th century, the Black Death in the 14th century, and the Third Pandemic that originated in China in the 19th century.

In these pandemics, it’s generally thought plague was introduced by rats (often transported on ships) then transmitted to local rats in domestic settings. Fleas then transmit the bacterium between infected rats and humans. But there’s still some debate on the transmission pathways of plague in these pandemics. The classical cycle between an animal reservoir (rats) to humans through an insect vector (fleas) is common to many animal-associated infectious diseases, known as zoonoses.

The pattern of plague cases seems to have changed to a more complex ecology over the past 50 years. There has been a shift in cases from Asia to Africa and the re-emergence of disease in other areas such as the United States.

It’s now recognised there are many potential pathways of transmission from animals to humans in different settings. In the US, plague is thought to be transmitted from wild rodents in rural areas, such as prairie dogs and rock squirrels.

In some African countries, it’s thought cases arise where there is human encroachment into forest areas. Outbreaks have also been linked to the consumption of infected camel and goat meat in Libya, and from exposure to infected guinea pigs during preparation for cooking.

In recent years, there’s been interest in the impact of climate change on the potential for outbreaks. The prevalence of plague in animals in Kazakhstan is associated with higher temperatures in spring and rainfall in summer, as are outbreaks in the US. Tree ring studies also suggest similar climatic conditions may have triggered the Black Death and the Third Pandemic.

How can it be controlled?

Modern plague control includes finding cases and treating them, and where cases are detected, clearing homes of fleas using insecticides. Plague cases in hospitals need to be cared for safely to prevent spread to health care workers and other patients.

In affected communities, people should act to keep rats out of homes. This includes making sure food is stored and disposed of safely. Avoiding bites from fleas is also important, using insect repellents and ridding animals of fleas. Although rat control using poisons can also be used, this should only be done after fleas have been controlled, as fleas can leave dying rats and make things worse.

At a national and international level, systems to respond to outbreaks are required to make sure the public receives reliable information, to deploy logistics and resources to where they are required, and co-ordinate the various national and international organisations involved in the response.

How easily can it spread between countries?

Although the concept of quarantine arose from efforts to control plague spread, travel and trade restrictions are not often warranted given their potential economic impact. The wider fallout from outbreaks can be severe. For example, a relatively small outbreak, mostly localised to the city of Surat in India in 1994, provoked widespread panic. This resulted in a national collapse in tourism and trade that was estimated to cost up to US$2 billion.

In this current outbreak, only the Seychelles has implemented travel bans, and it’s thought the risk of transmission is low. Few confirmed cases have been reported in travellers from Madagascar during the current outbreak.

The World Health Organisation has been working with neighbouring countries to improve preparedness efforts. This includes improving surveillance at airports and sea ports, developing contingency plans and pre-positioning of antibiotics and protective equipment.

What is the future for plague?

It’s not possible to eradicate plague, as it is widespread in wildlife rodents outside the sphere of human influence. Outbreaks generally are managed reactively by “firefighting teams” deployed to clear houses of fleas, identify and treat cases and give pre-emptive treatment to contacts at risk.

The ConversationA more preventative approach, such as the identification of areas at risk using climate models and animal surveys to focus flea and rat control efforts would be better. But this requires a better understanding of transmission pathways in each region where disease persists.

Allen Cheng, Professor in Infectious Diseases Epidemiology, Monash University

This article was originally published on The Conversation. Read the original article.

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Haiti: Earthquake Tragedy


The terrible tragedy in Haiti continues to dominate world news, with fears that the death toll from the earthquake will top 200 000 deaths. 250 000 people were also injured in the earthquake and there is now a major effort to provide essential aid including food and medical provisions for the suffering Haitian population. This is a major tragedy and the world needs to respond to it – thankfully, this is happening.

The crisis will continue long after the headlines have ended, with some 2 million people having been rendered homeless as a consequence of the disaster. Millions of Haitians are at risk of illness and death as a consequence of the quake, with sanitary conditions, lack of drinking water, limited shelter, etc. These are just some of the problems that will continue to plague the poverty-stricken people of Haiti. The rebuilding process will be enormous and well out of reach of Haiti. The nation of Haiti will continue to need the assistance of the world for many years to come.

Organisations like World Vision, the Red Cross and many others, will need the continued support of governments and individuals around the world in order to continue to support and assist the victims of this earthquake. Please continue to assist by sending donations to the various aid organisations that are assisting in the work in Haiti. Over the coming days and weeks, ‘Random Thoughts’ will pass on information as to how people can continue to assist the Haitian people.

STATISTICS: particularbaptist.com


Since I have nothing much to ‘Blog on’ about tonight, I thought I might indulge in some more statistics. A few days back I wrote about 5 000 visitors at this Blog (which is now above 6 250 by the way), which got me to thinking about my main web site called particularbaptist.com (it used to be Aussie Outpost and before that NRBC – for Northlake’s Reformed Baptist Church).

Particularbaptist.com has been that name since July 2006, when I switched the site to a new hosting company and adopted the before mentioned domain name. The Aussie Outpost ‘brand (so to speak)’ had been established for some time and so the move to a new URL, name and domain would take some getting used to and the early stats showed this to be the case.

In July 2006 there were 333 hits on the site, with a total of 13 visits and 108 pages viewed. By the end of the year there had been 8 960 hits on the site, with a total of 643 visits and 3208 pages viewed. This was about what I would have expected given the changes and the effort involved in becoming re-established as particularbaptist.com.

Having looked at the statistics for the site a couple of days ago I was amazed at how strongly the site is now performing and it has encouraged me to continue with the work (I had been contemplating abandoning the project). All of those doubts that probably plague ‘webmasters’ were mine – is it worth the effort, is it at all useful and profitable to visitors, is it making a useful contribution, etc?

Anyhow, I have been encouraged to press on by the figures and have found that the statistics prove useful as that – encouragement. At times, that is very important – at least I think it is. So what are the latest figures?

Toward the end of September 2008 there had been 368 756 hits on the site, with a total of 35 979 visits and 233 571 pages viewed. All that in just over 2 years is simply amazing to me and above what I had expected by a long way. With the growth trend the site should have its 500 000th hit and 50 000th visit early in the new year and possibly a million hits by the end of 2009.

Isn’t the Internet incredible – so many visitors from all over the world?

I’ve started a statistics page on the site mainly for my own benefit (so I don’t have to wade through all of the figures over and over from the web host which is a bit complicated) and for supporters of the site at:

http://www.particularbaptist.com/stats.html

It’s all very simple on the statistics page at the moment and hopefully it will stay that way. I will be adding other bits of statistical trivia to the page over time, including a list of what countries the site has had visitors from. All very interesting.

The site’s homepage is pretty simple to find these days:

http://particularbaptist.com