Dengue Fever

 Five years ago I'd been using up some gift cards from amazon.com and had bought several items. Probably some music, but I don't remember what, and some books on disease including one on Yellow Fever. Some time later I got an e-mail highlighting items they thought I might like. I was amused to see they'd combined my viral hemorrhagic fever book with music to come up with the conclusion I'd like music by a band called Dengue Fever. The sort of stupid conclusion only a computer could reach. Except they were right.

In contrast to most bands with disease related names (eg Anthrax, Cholera, Bubonic Plague, Ebola etc etc) Dengue Fever are not only not a heavy metal band but play an impressive combination of almost everything else 'Southeast Asian pop, Vietnam-war-era lounge music, klezmer, ska, surf rock, and Ethiopian jazz'. One of the band apparently caught Dengue Fever which is where they got their name. I suspect Anthrax, Cholera, Bubonic Plague and Ebola can't say that. Dengue Fever (the band) are based in LA and so play in Santa Barbara quite frequently, usually at SoHo but next Friday (February 2nd) you can catch them right here on campus at the Multicultural Center.

If you want to know something about Dengue Fever, the disease, then read on.

Although it is the Filoviruses such as Ebola that leap to mind when people hear the phrase 'viral hemorrhagic fever' (VHF) there are actually four different families of viruses that can lead to the classic symptoms of VHF's - capilliary leak leading to high temperature, shock (loss of blood pressure) and death.

This is rather important because whilst the Ebolavirus is really very rare some of the other VHF's are far more common. We'll talk about Yellow Fever in the penultimate week but another disease in the same group is Dengue Fever. Although 50-100 million people are estimated to contract this mosquito borne disease every year only a minority get a severe hemorrhagic fever. Maybe 5%. But 5% of 50-100 million is still several million people per year! In the severe form Dengue Fever causes a very high fever (over 104) and generalized muscle and joint pain (hence the common name 'breakbone fever').

It is the most common viral disease transmitted by arthropods and it is deemed second in importance to malaria in terms of tropical diseases. The World Health Organization currently counts dengue as one of sixteen neglected tropical diseases and it is found in a wide range of tropical countries across South America, Africa and Asia.

Rabid

I don't cover rabies in this course but if you are interested in diseases generally you may want to check out a new book '“Rabid: A Cultural History of the World’s Most Diabolical Virus”. Here's part of a review from the New York Times where they point out what a fabulous example of vaccination success rabies is.

(R)abies vaccinations for dogs, which have always seemed to me a bureaucratic annoyance (who gets bit by rabid dogs these days anyway?), have produced one of the historic successes in public health.

Hardly anyone in developed countries gets rabies now because dogs are routinely vaccinated.

In the rest of the world, however, 55,000 people die each year of rabies. 

And a lurid detail about rabies I didn't know.

(R)abies, on its inexorable death crawl through the nervous system to the brain, can cause sustained erections, and on rare occasions frequent, and uncontrollable ejaculations in human males.

The authors write, “case reports from history describe up to thirty ejaculations in a single day” and go on to note that “The Roman physician Galen, in his own remarks on rabies, describes the case of an unfortunate porter who suffered such emissions for three full days leading up to his death.”

Bonus viral hemorrhagic fever

Although it is the Filoviruses such as Ebola that leap to mind when people hear the phrase 'viral hemorrhagic fever' (VHF) there are actually four different families of viruses that can lead to the classic symptoms of VHF's - capilliary leak leading to high temperature, shock (loss of blood pressure) and death.

This is rather important because whilst the Ebolavirus is really very rare some of the other VHF's are far more common. We'll talk about Yellow Fever in the penultimate week but another disease in the same group is Dengue Fever. Although 50-100 million people are estimated to contract this mosquito borne disease every year only a minority get a severe hemorrhagic fever. Maybe 5%. But 5% of 50-100 million is still several million people per year! In the severe form  Dengue Fever causes a very high fever (over 104) and generalized muscle and joint pain (hence the common name 'breakbone fever').

It is the most common viral disease transmitted by arthropods and it is deemed second in importance to malaria in terms of tropical diseases. The World Health Organization currently counts dengue as one of sixteen neglected tropical diseases and it is found in a wide range of tropical countries across South America, Africa and Asia.

In 2008 I'd been using up some gift cards from amazon.com and had bought several items. Probably some music, but I don't remember what, and some books on disease including one on Yellow Fever. Some time later I got an e-mail highlighting items they thought I might like. I was amused to see they'd combined my viral hemorrhagic fever book with music to come up with the conclusion I'd like music by a band called Dengue Fever. The sort of stupid conclusion only a computer could reach. Except they were right.

In contrast to most bands with disease related names (eg Anthrax, Cholera, Bubonic Plague and Ebola) Dengue Fever are not only not a heavy metal band but play 'Southeast Asian pop, Vietnam-war-era lounge music, klezmer, ska, surf rock, and Ethiopian jazz'. One of the band apparently caught Dengue Fever which is where the band got their name. I suspect Anthrax, Cholera, Bubonic Plague and Ebola can't say that. Dengue Fever (the band) are based in LA and so play in Santa Barbara quite freqeuntly, usually at SoHo - twice last year for some reason. 1000 tears of a tarantula is the first song link I clicked on and is still my favorite song of theirs.

Walter Reed: Physician, Researcher, Soldier

From the Military Health System website at the Department of Defense a short video about Major Walter Reed’s contributions to military medicine, which include discoveries that paved the way for health care modernization at the dawn of the 20th century.

Robert Koch and Rinderpest

The German physician and microbiologist Robert Koch is most famous for developing the germ theory of disease and for proposing that ‘one germ causes one disease- every disease has its specific germ’.

Koch and his pupils found the organisms responsible for tuberculosis, anthrax, diphtheria, typhoid, pneumonia, gonorrhoea, cerebrospinal meningitis, leprosy, bubonic plague, tetanus, and syphilis, among others.

In 1896 Koch was brought to South Africa by the Cape Government to investigate and find a cure for cattle plague, or Rinderpest, which had broken out during the last decade of the 19th century. The epidemic affected most of southern African, but it hit the Transvaal and Northern Cape particularly hard.

Although he did not identify the cause of this disease, he succeeded in limiting the outbreak of it by injection into healthy farm-stock of bile taken from the gall bladders of infected animals. He announced the discovery of his vaccine on 10th February 1897.

Eradicating Rinderpest

A short 4 minute video that explains a little more about the eradication of Rinderpest.

Scientific innovation, international collaboration and investment from donors, such as/including the UK's Department for International Development, supported the work of teams of community health workers wherever rinderpest attacked cattle. Two of the scientists involved, Dr John Anderson and Dr Michael Baron, explain what has been achieved and how.

After the Rinderpest

Whilst there is, of course, a death metal band called Rinderpest, with a song called Rinderpest, I couldn't make much headway with the 'lyrics'. Let me know if you have better luck.

More interestingly there is a South African musician who has a whole album about the Rinderpest epidemic that devastated Africa.

The Scene is the Cape Colony border, late 19th century, a terrible plague, the Rinderpest (rather like Foot & Mouth), has decimated the livestock and lives of the Boers, Brits and Amaxhosa alike. The infected animals have to be piled in pits and burned. The land is covered in smoke and weeping.

It's not easy to find but you can download an mp3 of the title song , After the Rinderpest, from the Last.FM website.

After the Rinderpest

 

There’s a wicked wind on the smoking ground

All out hopes and dreams, we had to burn them down.

And our poisoned wells took our first and best

Gave our childrens’ lives to the Rinderpest.

 

Sent our youths away to be militarized

And we couldn’t see into their empty eyes.

Would you have the strength, if they confessed

To what they saw, in the wilderness.

 

With a burying pit full of burning beasts

With the crimson coals of the heat beneath.

Holding out our hands to be cauterized

But the Rinderpest left us paralyzed.

 

And a tattooed child full of battle scars

With a heart of iron, hammered hard.

Do we act surprised, as though we never knew

What the sulphur air would have done to you.

 

There are bands of us that have survived

And all we have is how we live our lives.

As we struggle on, we must not forget,

Just what we learned, from the Rinderpest.

Of Mice and Man

The Center for Disease Control has a weekly podcast called 'A Cup of Health'. In a recent issue Dr. Barbara Knust discusses Hantavirus Pulmonary Syndrome. It's a bit cheesy but has some good advice

Remember, if you think you might have an infestation of rodents in or around your home, be careful not to stir up any dust or dirt that might contain the virus. Then, clean up the area with household disinfectants or bleach.

And why is this mouse pink? Well that's a completely different story from 2009:

University of Utah researchers dusted wild deer mice with fluorescent pink, blue, green, yellow and orange talcum powders to show which rodents most often fought or mated with others and thus were most likely to spread deadly hantavirus. The study identified bigger, older mice as the culprits.

Rinderpest

A technician from Ethiopia's National Veterinary Institute vaccinates cattle against rinderpest (1987).

Scientific American had an article at the end of last year about the elimination of Rinderpest - Cattle plague: An extinction worth celebrating

In the 1980s, billions of dollars worth of livestock were lost in several major outbreaks in South Asia, the Middle East and Africa.

Flash forward to 1994, when the FAO formed the Global Rinderpest Eradication Program (GREP). Working with government agencies and organizations around the world, GREP charted the geographic distribution of rinderpest, worked to understand the disease better, and took local action to fight it.

Local actions included training veterinarians and farmers to recognize and report the rinderpest, establishing emergency response plans, setting biosecurity protocols, and working with countries to create programs for monitoring and controlling the disease.

The efforts paid off. In the past 15 years, 170 countries and territories have been certified as rinderpest-free by the World Organization for Animal Health, the international certification body for animal diseases. The last major outbreak was in Kenya in 2001, and the disease's final stronghold was in a small, overlapping area of Somalia, Ethiopia and Kenya that the FAO now says appears to have been cleared.

It now looks like rinderpest has been essentially eliminated but formal declaration of victory is on hold whilst surveillance continues to ensure it is really extinct. An international statement about Global Rinderpest Freedom is expected to be made within the year 2010. This would be the second time that a disease has been eradicated worldwide after smallpox in humans. FAO have a Status report on progress made to date in eradication of rinderpest: highlighting success story and action required till global declaration in 2010 (links to pdf document). I think this document illustrates the difficulty of working on a global scale.

Valentines Day repeat - Dengue Fever

Okay, so it's a repeat but I felt like listening to it. In contrast to most bands with disease related names (eg Anthrax, Cholera, Bubonic Plague and Ebola) Dengue Fever are not only not a heavy metal band but play 'Southeast Asian pop, Vietnam-war-era lounge music, klezmer, ska, surf rock, and Ethiopian jazz'. One of the band apparently caught Dengue Fever which is where the band got their name. I suspect Anthrax, Cholera, Bubonic Plague and Ebola can't say that. Dengue Fever (the band) are based in LA.

Dengue fever (the disease) is a hemorrhagic fever caused by a virus found primarily in the tropics and Africa, with a geographical spread similar to malaria. Dengue is transmitted to humans by mosquitos. Although it is a hemorrhagic fever the mortality rate, especially with medical care, is much lower than other hemorrhagic fevers such as Ebola hemorrhagic fever.

The video isn't actually a video but I like this track - One Thousand Tears Of A Tarantula.

Happy Valentine's Day

Rabies

Another zoonotic disease I briefly mentioned in passing was rabies. As you may know rabies is a very nasty viral disease that is invariably fatal once symptoms appear. Only six people are ever know to have survived rabies after symtpoms appeared, the last one a girl bitten by a rabid bat in Wisconsin in 2004.

Although it only causes a handful of cases a year in developed countries, and has been eliminated in some it still causes over 24,000 deaths a year in Africa, mostly children in poor rural communities.

A recent paper in the Journal of General Virology analyzed 182 samples of dog rabies virus from 27 African countries taken over a time period of 29 years. They showed that most of the rabies virus circulating in dogs in western and central Africa comes from a common ancestor introduced to the continent around 200 years ago, probably by European colonialists.

Dr Hervé Bourhy et al. Evolutionary history and dynamics of dog rabies virus in western and central Africa. Journal of General Virology, (in press)

Modern perils

In poor countries inadequate sanitation and garbage disposal, combined with poor resources at a local level mean there are numerous habitats for mosquitoes to breed in. From abandoned drainage ditches to discarded tires, buckets and bottles the problem is immense. In the absence of environment blanketing DDT the focus has turned to bednets - keeping mosquitoes (at least the nocturnal ones) from biting people.

In the developed world a new problem is arising - abandoned swimming pools. This problem has increased with the recent sharp rise in foreclosed and abandoned homes. In America the concern is not Malaria but West Nile virus. Fortunately such mosquito magnets can be detected remotely (although somewhat expensively) by the use of aerial surveys. Abandoned pools are generally green with algae. This is a regular tool in mosquito abatement in the Bay Area. For example, see this article today in the San Jose Mercury News:

The Santa Clara County Vector Control District will conduct an aerial search Monday for mosquito breeding sources that could potentially carry West Nile virus.

The district has made two previous aerial surveys this year, in early May and early August, which have led to more than 860 inspections and 135 treatments or fish plantings on local properties.

There's a longer article here about the problem in San Bernadino County. Remember the bottom line from this class - whenever anything changes in society there are new possibilities for disease transmission, potentially leading to outbreaks of new diseases or resurgences of old diseases.

HPV and Cervical Cancer

I didn't have time to say much about the Human Papillomavirus vaccine but I did want to mention the issue. PBS have a very nice site from a show on the subject
You can watch the whole show at the site, or download it as an mp3 file to listen to, and also read an interview with a 'vaccine expert' that raises interesting issues and find out the basic facts about HPV and the vaccine. If you can't see what all the fuss is about take a deep breath and read some of the posted comments.

Also, over the next couple of days I will be writing the midterm and will post some sample questions here. I'll also put up a cumulative list of the terms we have covered to date (ie a subset of the larger glossary) which might be useful.

Relevant material previously on the blog:

Well, this post actually but I wanted to draw particular attention to it.
Solver for the SIR Model of the Spread of Disease
Vaccine safety
The height of reckless irresponsibility

Vultures, drugs and rabies

Over the last few years you may have heard stories about the decline of vultures in India. Population declines of over 95% were observed and some species may go extinct. One reason the press picked up on this around 2004 was the implication for the Indian Zoroastrian Parsi community, who traditionally use vultures to dispose of human corpses in "sky burials".

Eventually it was worked out that the vultures were dying because of a drug, diclofenac, commonly used in livestock. Vultures fed on livestock, ingested the drug, and died.

Now a new study, published in Ecological Economics this week, suggests that this loss of vultures may have led to an additional 50,000 rabies deaths in India. As the vulture numbers declined so the number of feral dogs increased. India has one of the world's highest incidences of rabies. and some of these dogs would have been infected with rabies. Calculations suggest an additional 5.5 million feral dogs between 1992 and 2006 leading to an additional 38.5 million dog bites. In India 123 people die of rabies for every 100,000 dog bites. This suggests at least 47,300 people died of rabies as a result of the vulture die off. Rabies is a very nasty viral disease which has a very high fatality rate. In fact, once symptoms develop, death is practically inevitable. There are only six known cases of a person surviving rabies once symptoms have developed. The best chance of surviving rabies is a prompt post-exposure vaccination that may prevent the virus from progressing to the symptomatic stage.

There is some evidence that vulture numbers may, in some areas of India, be starting to increase after the widespread use of diclofenac was discontinued.

Dengue fever

In a strange crossing of interests, Amazon.com just recommended the latest release by a band called Dengue Fever to me. Usually I disregard these e-mails but this one obviously caught my eye. On further investigation I am happy to report that Dengue Fever are not only not a heavy metal band but play 'Southeast Asian pop, Vietnam-war-era lounge music, klezmer, ska, surf rock, and Ethiopian jazz' AND one of the band apparently caught Dengue Fever which is where the band got their name. I suspect Anthrax, Cholera, Bubonic Plague and Ebola can't say that.

Dengue fever is a hemorrhagic fever caused by a virus found primarily in the tropics and Africa, with a geographical spread similar to malaria. Dengue is transmitted to humans by mosquitos. Although it is a hemorrhagic fever the mortality rate, especially with medical care, is much lower than other hemorrhagic fevers such as Ebola hemorrhagic fever.

(Sorry the video isn't actually a video but I like this track - One Thousand Tears Of A Tarantula.)

Expecting the unexpected part 2

An update to an earlier post about the norovirus outbreak in the UK. Now that the hysterical news reports have died down there are some more serious and questioning reports. The Times Online has a fairly sensible Q&A on whether there is an epidemic or not and the Guardian has a brief article asking whether the epidemic is a myth.

Expecting the unexpected

'Doctors estimate that more than 100,000 people a week are catching the bug.' Wow. That has to be quite an epidemic.

When is an epidemic not an epidemic? When you can see it coming. Lots of diseases, such as the common cold and influenza, are somewhat seasonal but we wouldn't necessarily refer to the peak each year as an epidemic because it is not unexpected based on past patterns. On the other hand sometimes we get a larger peak than normal, such as a new strain of influenza, and it is then appropriate to call it an epidemic. The press doesn't always make this distinction but it is an important one.

There is currently a potential epidemic of norovirus in England. The press seem to prefer to call it the 'vomiting bug' eg. on the BBC website Many wards closed by vomiting bug. However even though you may not have heard of norovirus before it is actually very common, causing about half of all cases of viral gastroenteritis (stomach pain, diarrhea, and vomiting). Viral gastroenteritis is second only to the common cold as a cause of illness in the U.S. The graph at the top of this page shows the seasonal nature of norovirus outbreaks over the past few years. It looks like there was an increase from2001-2006 compared to 1998-2000 but whether the 2008 outbreak will become an epidemic is complicated by the fact that the press reports on it will themselves increase the number of people seeking medical advice. Cases are apparently at a 5-year high with between 100,000 and 200,000 cases a week and an estimated 2 million in total. This raises a couple of interesting points about the definition of an epidemic:

• We can see epidemics on different time scales. There may be an ongoing, longer term epidemic of norovirus since 2001, AND there may be an epidemic this year.
• Epidemics can be confused by publicity. More cases are reported when a disease hits the headlines - this does not always mean there is a real increase in the disease. For example Ronald Reagan's Alzheimer's diagnosis led to a huge press coverage and an apparent outbreak of Alzheimer's in the US. In reality it was almost certainly just due to the reporting and the increased awareness led to improved and earlier diagnosis of existing cases.
  

Norovirus fun true fact: The Norwalk virus was named after Norwalk, Ohio, where an outbreak of acute gastroenteritis occurred among children at an elementary school in November 1968. Noroviruses are named after the Norwalk virus.

Norovirus dubious fact: according to the Daily Mail 'newspaper' in England norovirus 'is 100,000 times more infectious than salmonella.' Hmmm, that is interestingly precise. I wonder what scientific morsel is behind that statement.