Archive for category: Disease

Information and news about disease category

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Climate Change and Pathogen Ranges

The effects of climate change are numerous: ocean levels are rising, meteorological events are becoming stronger and increasingly unpredictable and the incidence of heat-related illness is increasing across the world. Yet experts are just beginning to understand one effect of a changing climate: the capacity for pathogens to migrate around the globe and infect populations that have previously never been in contact with these microorganisms.

Combined, these effects have the potential to cause extreme poverty. Loss of property and life resulting from rising sea levels and strong storms deprive people of both wealth and other resources.

However, the global health conundrum that is changing pathogen ranges is also a poverty issue in its own right. Poor human health places burdens on individuals and their family members that may cause them to lose employment opportunities and large sums of money. Being ill is no easy fortune, but the impoverishment that often accompanies illness can be worse yet.

As warming weather drives animals toward more hospitable environments, pathogens too are expanding their ranges and at the same time, are finding hosts they’ve never met. While it’s working out well for these pathogens, humans, other animals and plants aren’t faring too well.

A species of sea otters in the Pacific Ocean off the coast of Alaska has become ill from a virus that originated in the northern Atlantic Ocean; science writer Chris Solomon suggests that due to declining sea ice levels, “disease is finding new lanes of travel.”

It makes sense – pathogens are highly dependent on temperature for survival, and many bacteria and viruses thrive in the type of warm, wet environments that are becoming more and more prevalent as the climate changes. Not only do rising sea levels give pathogens access to a wider range of space (and accordingly, hosts) but also as animals move around seeking cooler climates, they take pathogens and parasites along with them, allowing them to infect entirely new populations.

What does this mean for humans? Well, the effects of expanding pathogen ranges are manifold. First, like Alaska’s sea otters, humans may soon fall prey to microorganisms not previously seen in their parts of the world. Prevention and treatment of illnesses caused by unfamiliar pathogens will be difficult and costly.

Inevitably, some humans – though it is impossible now to estimate just how many – will die.

Since human health is directly related to poverty outcomes, the expanding pathogen ranges means expanded poverty “ranges;” if more people fall ill due to pathogens, more people will experience poverty.

Secondly, and this is an effect that agricultural communities are already beginning to observe, new pathogens will infect crops and jeopardize the livelihood of the peoples who depend on the harvest for either food or for employment.

According to a study from the Universities of Exeter and Oxford, crop threats include pests and pathogens spreading toward the poles at a rate of 3.2 kilometers per year. A fungus that infects yeast harvests has already wreaked havoc in Brazil, threatening farmers there with impoverishment.

It’s difficult to fathom that such tiny organisms could have such large effects, but pathogens have the potential to cause a lot of harm, in terms of both illness and poverty. Despite that their migration is one of the least publicized effects of climate change; however,  it is one of which humans should be wary.

– Elise L. Riley

Sources: NPR, NASA
Photo: Phys.org

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Yellow Fever in the Developing World

Despite increased understanding of the mosquito-transmitted disease since it presented in the 15th century, yellow fever in the developing world continues to have a widespread effect. The World Health Organize  estimates that there are 200,000 cases of yellow fever every year, with 30,000 deaths, 90 percent of which occur in Africa. In Africa and Latin America, 900 million people are at risk of infection as the disease spreads without a cure.

When a mosquito bites a person and transmits yellow fever, there are two paths the disease can take. It will either present as flu like symptoms with fever, aching and nausea, before going away in three to four days. However, 15 percent of patients take the second path. Symptoms worsen rapidly, as the patient develops jaundice, bleeding and increased vomiting. Half of these patients die within 14 days, and those who survive suffer from severe organ damage.

The fight against yellow fever is challenging for a few reasons. For starters, in the early stages, it is difficult to diagnose the disease, as its symptoms are similar to diseases like malaria, viral hepatitis and poisoning. Once the disease can be identified, it is often too far along to effectively control.

Additionally, yellow fever has no treatment. Though it can be prevented, there is no vaccine to cure it. Patients are often treated for secondary conditions that result from yellow fever, which can be effective in helping the patient survive the disease.

Despite the lack of treatment, there are myriad methods to prevent yellow fever. The GAVI Alliance, which has brought together the efforts of the WHO, UNICEF, the World Bank, the Bill and Melinda Gates Foundation and various other governmental agencies, has been successful in administering preventative vaccines worldwide. Since GAVI got involved, an estimated 64 million children have had the vaccine, and 17 of the 33 countries at risk have received routine vaccinations.

In addition to vaccination, protection from mosquitoes can be effective in preventing yellow fever, whether it be insecticide treated nets, clothing that covers as much skin as possible or remaining indoors at night when the mosquitoes are in abundance.

The WHO has been involved beyond its participation in the GAVI Alliance, acting as Secretariat for the International Coordinating Group for Yellow Fever Vaccine Provision. The ICG is adamant about maintaining a stockpile of yellow fever vaccinations in case of a sudden outbreak. Additionally, the WHO along with UNICEF and national governments has led the Yellow Fever Initiative which focuses its vaccination efforts in Africa, targets infants younger than nine months and works to monitor outbreaks to minimize damage.

Preventing yellow fever is very much dependent on efficient healthcare and sanitation, things that are difficult to achieve in impoverished areas. The efforts of GAVI, as well as the individual organizations, are crucial to control the number of yellow fever cases every year.

– Maggie Wagner

Sources: Gavi Alliance, NCBI, WHO
Photo: Gavi Alliance

Ebola in Sierra Leone

The Ebola outbreak spreading across Africa has become increasingly fatal over the past couple of months. The incubation period for Ebola ranges from two days to 21 days, and when not treated early on, has about a 90 percent fatality rate.

According to WHO, 630 people total in the West African countries of Sierra Leone (442 people infected, 206 deaths), Guinea (410 people infected, 310 deaths) and Liberia (196 people infected, 116 deaths) lost their lives to Ebola. One of the most recent victims of the disease includes one of the leading doctors in Sierra Leone, Sheik Umar Khan, who contracted the virus while attempting to help treat others afflicted by Ebola.

Psychologist Ane Bjoru, who has begun work in Sierra Leone, however, explains the impact of Ebola beyond purely the physical effects of the virus. In her article in The Guardian, she explains that as a non-medical staff member, a large part of her job is helping hygienists, who have to deal with disposing of the dead bodies, deal with this “new and disturbing experience” and much of her work “involves helping them with counseling and support.”

Ane Bjoru explains that to treat Ebola in Sierra Leone the hygienists are responsible for cleaning the blood and stool produced by the patients, and are confronted with a confusing mix of emotions when dealing with the dead bodies. They are filled with sadness from the loss, fear from the contagious bodies, and especially in Sierra Leone where the dead are usually dealt with by the elders of the society, some of the hygienists feel they are too young to be involved with this part of the life cycle.

Ane Bjoru, through her work, seeks to build a wider community of people to help citizens of Sierra Leone deal with the emotional consequences of the Ebola outbreak.

— Jordyn Horowitz

Sources: World Health Organization, The Guardian 1, The Guardian 2, BBC News
Photo: The Guardian

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Causes of Malaria

Malaria, a disease largely eliminated in the developed world, remains a health issue for developing nations. According to World Health Organization estimates, 207 million cases of the deadly disease emerged in 2012 alone, with about 80 percent coming from countries in Sub-Saharan Africa.

To help communities in these nations fight malaria, NGOs and foreign aid providers must not only provide malaria treatment methods but also find ways to address and protect people from its causes.

So, what are the causes of malaria?

The Mayo Clinic identifies the main path to infection as the transmission of parasites through mosquitoes. Mosquitoes can carry small parasites that cause malaria, and when they bite humans the parasites can enter the bloodstream. Once in the body, the malarial parasites travel to the liver, where they grow and develop. The maturation process lasts from a week to nearly a year, but once the parasites reach adulthood, they enter the bloodstream and infect red blood cells.

At this stage, the common symptoms of malaria, including fever, chills and sweating, develop. At the same time, mosquitoes that suck infected blood will get the malarial parasites, allowing them to spread through bites to other people.

Though malaria primarily spreads through mosquito bites, people can contract it from other sources. Malaria is a blood-borne disease, and receiving blood transfusions from infected individuals can lead to transmission. Sharing dirty hypodermic needles will also cause malaria to spread, and mothers can pass the disease on to their unborn children.

If left untreated within 24 hours of the first symptoms, malaria can cause brain damage, fluid buildup in the lungs and liver failure, all of which can be fatal. The World Health Organization believes that in 2012 malaria killed 627,000 people, the majority of whom were African children under five.

Fortunately, the mortality rates of malaria have fallen 42 percent globally since 2000. Still, the disease is lethal enough that a child in Africa dies every minute from malaria-related symptoms.

With no existing vaccine for the disease, programs to reduce deaths must focus on preventing malaria and safely treating existing cases.

Knowing that mosquitoes are the primary transmitters of malarial parasites, what do governments and other organizations do to prevent bites?

According to the World Health Organization, the two primary methods to keep mosquitoes away from people and their homes are to use insecticide-treated nets and indoor residual spraying of insecticides.

Projects from NGOs and foreign aid agencies to provide these services to communities free of charge will help prevent mosquitoes from spreading malaria.

While using either insecticide-treated nets or indoor residual spraying to stop mosquito bites is effective, the Institute for Health Metrics and Evaluation found that, in areas of medium transmission, using both methods reduced the risk of infection an extra 36 percent compared to one method alone.

Public education programs to teach people and doctors not to reuse medical equipment, not to give transfusions of infected blood and how to recognize symptoms quickly can also supplement insecticide-treated nets and indoor residual spraying to stop malaria at its source.

Malaria is a dangerous disease that takes the lives of many young children daily, but since people know what causes malaria, it can be prevented. Thanks to technology to kill parasite-carrying mosquitoes, deaths from malaria are dropping and the world is becoming a safer place to live.

– Ted Rappleye

Sources: The Mayo Clinic, World Health Organization, Institute for Health Metrics and Evaluation
Photo: TreeHugger

Rats Detecting Tuberculosis  

Rats are commonly thought to carry disease, but what if they diagnosed disease instead? In fact, they do. Contrary to popular belief, rats are highly intelligent creatures that can be trained to sniff out specific odors with incredible accuracy. They have already been used in warzones to sniff out landmines; now, a research center in Tanzania has rats detecting tuberculosis in patients’ saliva.

The giant rats being trained are especially successful at distinguishing an affected person’s saliva because they can smell “in stereo,” meaning that with one sniff they can differentiate two different odors. One out of every 100 rat genes is dedicated to their olfactory abilities – in humans, only one of every 1000 genes has to do with our capacity to smell. Rats’ superior noses allow them to diagnose a TB patient in only seven minutes. Diagnosis by human physicians can take all day.

Working to make TB diagnosis easier and more accurate is especially important for low- and middle-income countries, where 95 percent of all TB-related deaths occur. If caught early, TB can be treated with a course of antibiotics. Because TB is a bacterial disease, its symptoms may not present for long periods of time; the bacteria, which are spread through the air when affected individuals cough or sneeze, can lie dormant in the body before they begin to cause more severe symptoms. Because rats use the smell of the bacteria rather than a patient’s symptoms to diagnose TB, they can diagnose patients much earlier than doctors can.

Though the equipment and expertise necessary to train these rats can be somewhat expensive, this method has the potential to save over a million lives and prevent illness in nearly nine million more every year.  Foreign aid could be useful in providing trained rats to health centers in developing countries or assisting in the training of rats abroad.

Seeing rats as agents of health rather than disease is the first step to eliminating TB altogether. By bringing these intelligent animals into our health centers and our hearts, we can prevent the transmission of one of the world’s deadliest diseases.

– Elise L. Riley

Sources: World Health Organization, BBC
Photo: Flickr

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Controlling Malaria Outbreaks

Combating poverty drives innovation. In order to reduce the suffering from poverty, countries investigate cost effective methods of preventing poverty and reducing the negative effects of poverty, such as disease or malnutrition. Confronting public health concerns, like malaria, in developing countries inspires scientific innovations to end the problem in an efficient yet inexpensive way. In this way, controlling malaria outbreaks improves health care worldwide.

Malaria is preventable and treatable, yet the disease killed over 600,000 people in 2012. The Center for Disease Control reported that malaria outbreaks are the leading cause of death in many developing countries and disproportionately affects young children, pregnant women and travelers.

Malaria is both a symptom and cause of poverty. Impoverished people struggle to take preventative measures against malaria, and if individuals contract malaria, the cost of treatment and the inability to work burden them. Furthermore, countries must create and manage health facilities and treatments. The Center for Disease Control estimated the direct cost at $12 billion per year. This creates a cycle of poverty in which both people and nations are unable to escape.

Some of the solutions, though, destroy too many mosquitoes, which affects the environment. Many predators depend on mosquitoes as their primary food source, so the ecological effect of eliminating all mosquitoes would be significant.

Because of this, researchers are investigating effective preventive measures to target a specific type of mosquito. The Economist reports that Dr. Nikolai Windbichler and Dr. Andrea Crisanti found a method of killing only the mosquitoes of the Anopheles genus, or the ones that carry malaria. By ensuring that the mosquitoes no longer produce female mosquitoes, Dr. Windbichler and Dr. Crisanti ensure that the mosquitoes cannot reproduce or draw blood and spread the malaria parasite.

The researchers designed a protein called endonuclease, which erodes the X chromosome of the mosquitoes. Producing female offspring requires two X chromosomes, and the egg only holds X chromosomes. As a result, if the protein limits the production of X chromosomes in male mosquitoes, it will limit the amount of female mosquitoes produced. A male dominated species of mosquitoes would lower the population as a whole and limit the transmission of malaria.

However, the Economist notes that natural selection will eventually allow the mosquitoes to evolve past the protein, so this solution depends on the elimination of the parasite within the species.

Ecologist Phil Lounibos expresses some skepticism of this type of solution. He believes that eliminating or decreasing the population of one species will not affect the spread of the disease. In a study he led, multiple genus of mosquitoes would cross inseminate and spread the parasite to other types of mosquitoes.

Stalling the disease, though, could allow countries to divert funds from malaria treatment to increasing economic productivity and improving the lives of the country’s impoverished. Developing new methods of malaria control presents exciting possibilities for controlling and combating malaria.

Between 2000 and 2012, malaria interventions saved over 3 million lives, and scientific innovation could drastically increase this number.

– Tara Wilson

Sources: The Economist, Center for Disease Control, WHO, Nature
Photo: The Health Site

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Five of the Most Common Killer Diseases

The Global Post has drawn up a list of the world’s biggest killers by using information from the World Health Organization. Below are a list of some of our most common killer diseases per country.

5. Cirrhosis of the Liver

Caused by excessive drinking, the disease is unique to Mexico as the only place in the world where it is the primary cause of death. Yet the disease is nothing to roll your eyes at: caused by healthy liver tissue being replaced by scar tissue, the scar tissue blocks the flow of blood, nutrients and other important proteins through the liver. Cirrhosis of the liver is the 12th leading cause of death by disease in the world — except for in Mexico, where it’s number one.

4. Tuberculosis

Tuberculosis is often thought of as a disease of the past, but it is still affecting millions of people around the world. In fact, it’s on the rise — the World Health Organization reports around 500,000 new TB cases each year, and it is second only to AIDS as an infectious killer worldwide. A bacterial infection that can spread through the lymph nodes and blood stream to any other part of the body, TB is the leading cause of death in areas such as Pakistan and North and South Africa.

3. HIV/AIDS

Despite the enormous progress made at slowing down the spread of HIV/AIDS, it is still the leading cause of death throughout most of Africa. Just two years ago, around 25 million people — roughly 70 percent of the global total — were living with HIV/AIDS in Sub-Saharan Africa, and an estimated 1.6 million new HIV infections and 1.2-million AIDS related deaths were reported that same year. In areas such as South Africa, Botswana and Swaziland, the percentage of HIV-prevalence is as high as 26.5 percent.

2. Cancer

It would be hard to find someone not somehow directly affected by cancer. As the second-leading cause of death in the world, cancer has certainly taken its toll — especially in areas such as France, the Iberian peninsula, Austria, Switzerland, the Netherlands and Denmark, where cancer (primarily lung and throat) is the leading cause of death. Classified as the rapid growth of cells, there are more than 100 types of cancer that we currently know about.

1. Heart Disease

It’s no surprise that heart disease tops the list as the world’s deadliest killer, but it is a little shocking to see the massive list of countries where heart disease outranks all other diseases. These countries include Canada, the United States, Russia, Australia, most of South America and part of Africa, to name a few. From first- to third-world countries, heart disease continues to remain the deadliest disease in the world.

– Nick Magnanti

Sources: International Business Times, WebMD 1, WebMD 2, The New York Times, Medical News Today, AVERT, CDC
Photo: Diseases-Causes-Cure blog

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Cholera in the Developing World

In the 1800s, cholera emerged from its place of origin in India and ravaged the world. Millions have died in the seven cholera pandemics that have occurred since the first appearance of the disease. While it has been eradicated in some regions, others continue to suffer from recurring epidemics.

Cholera is rarely seen in industrialized countries due to proper sanitation systems. Additionally, the World Health Organization (WHO) states that up to 80 percent of cholera cases can be “successfully treated with oral rehydration salts.” However, the bacteria that causes cholera can easily “continue to thrive” in areas with poor sanitation and overcrowded housing. While the developed world may not face the threat of cholera, in recent years, developing nations have seen deadly outbreaks.

Cholera is an “acute diarrheal disease,” which, in severe cases, can cause “profuse watery diarrhea,” vomiting, and muscle cramps. The Centers for Disease Control and Prevention reports that even more severe symptoms include “acute renal failure, severe electrolyte imbalances and coma.” The disease is potentially fatal just hours after developing symptoms.

The severity of cases often varies, says the WHO. Of those infected with the bacteria, 75 percent do not develop symptoms. While this may seem like a non-issue, the bacteria continue to exist in their fecal matter for up to two weeks. Without proper sewage sanitation, others may come in contact with the bacteria as well.

The remaining 25 percent of people infected do develop symptoms. However, 80 percent of those with symptoms only have mild or moderate ones. The other 20 percent of people experience serious, potentially deadly symptoms.

In 2008, the Vietnamese city of Hanoi experienced a cholera outbreak that produced upwards of 2,490 cases. The outbreak was attributed to sewage from septic tanks contaminating lakes where people sometimes wash food. Additionally, street food stalls and “dog meat” restaurants were closed down due to improper sanitation. Thirty lakes in Hanoi had to be sanitized due to the presence of cholera bacteria.

A cholera outbreak in Haiti, which began in 2010, has claimed 8,562 lives, according to the New York Times. Although relief efforts have reduced the number of cases, “clean drinking water and sanitation remain as scarce as when the epidemic began.” The number of cholera treatment centers has shrunk from 120 to 40, and the number of patients dying in treatment centers is rising. Doctors fear that the rainy season will cause the number of cases to skyrocket.

Medical News Today reports the ominous prediction that a cholera outbreak will strike Iraq. “Cholera is endemic in northern Iraq” already, says the report, and with the number of displaced people and refugees rising, the risk is even higher. Syrian refugee camps are overflowing with people, putting the water and sanitation standards at stake.

Two oral cholera vaccines exist, though the WHO has never recommended the vaccine “due to its low protective efficacy and the high occurrence of severe adverse reactions.” The best way to handle an outbreak, says the WHO, is to provide “prompt access to treatment, and to control the spread of the disease by providing safe water, proper sanitation and health education.”

These solutions, however, need to be applied in areas with the greatest need. The United Nations has come under fire for its response to the cholera outbreak in Haiti. The UN has failed to raise the amount of money necessary for vaccinations. While that would provide some immediate relief, Haiti also lacks the $2 billion necessary to construct safe water and sanitation services. Lasting relief is still in the distant future for the slowly recovering nation.

– Bridget Tobin

Sources: WHO 1, WHO 2, Medical News Today, IRIN, CDC, The New York Times
Photo: Medical News Today

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All About Dengue Fever

Dengue Fever
Though similar to malaria in its mode of transmission, dengue fever is its own monster. With up to 400 million people infected every year, dengue has been a leading cause of illness and death worldwide since the 1950s. According to the World Health Organization (WHO), 2.5 billion people around the world are at risk of contracting dengue fever.

Dengue is spread through the bite of a female Aedes aegypti mosquito, a species that seeks out prey during the daytime. The mosquito has recently spread to areas in North America and Europe, though it typically resides in tropical areas. Its presence in tourist destinations like Puerto Rico have caused a global spread, and put more people at risk.

Upon contracting dengue, symptoms present in a manner similar to the flu with high fever, headache, aches and pains and vomiting. The secondary symptoms require immediate treatment to ensure that dengue runs its course without escalation.

However, in developing countries where adequate medical care is unavailable, dengue fever escalates to dengue hemorrhagic fever, which is characterized by more extreme symptoms including hemorrhaging. This can then lead to dengue shock syndrome, and in 50 percent of shock cases there is a fatality.

There is no vaccine or treatment for dengue fever, but there are many preventative measures that can be taken to minimize infection. Insecticide can prevent transmission of the virus, as can mosquito nets and clothing that covers exposed skin. Additionally, proper disposal of waste and trash can cut down on mosquitoes.

While in developed countries dengue fever is very survivable, usually lasting between two and seven days, this virus hits the developing world much harder. Not only is there a higher prevalence in many impoverished tropical areas, they are also least equipped to prevent and handle dengue fever when it occurs.

The presence of such a debilitating and sometimes fatal disease worsens the poverty conditions in a country, in which a community needs resources and money to better protect themselves from the disease. Before that can happen, they need to be able to establish a healthy community to begin the transition out of poverty. This vicious cycle is difficult to overcome, making organizations like the World Health Organization instrumental in keeping these countries afloat.

The WHO assists in minimizing the burden of dengue fever by supporting “countries in the confirmation of outbreaks through its collaborating network of laboratories,” providing “technical support and guidance to countries for the effective management of dengue outbreaks,” and a slew of other helpful measures.

Raising awareness about the causes of dengue fever, as well as how to prevent it in the first place, is the first and most important step toward minimizing outbreaks, especially in the developing world. With the assistance of humanitarian organizations and the training of medical professionals to better respond to the virus, dengue fever will become a more manageable virus with fewer fatalities.

— Maggie Wagner

Sources: CDC, WHO, MedicineNet.com, National Institute of Allergy and Infectious Disease
Photo: NY Times

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Biosecurity and Global Health

The spread of infectious diseases is not only a threat to global health, but also to global security.

In recent years, diseases such as mad cow disease, avian flu, antibiotic-resistance tuberculosis and  antibiotic-resistant malaria have spread around the world. In a global age, the spread of disease becomes very easy. Eradicating infectious diseases and establishing effective ways to combat their spread is becoming important to national security.

In February of this year, the President Obama began the Global Health Security Agenda. Led by the United States, this agenda is a collaboration of 30 countries that is seeking to establish a world that is not threatened by the spread of infectious diseases.

In order to reach the goal, the Agenda  seeks to implement better systems of prevention, detection and response for infectious diseases around the world.

As part of prevention, the Agenda is creating laboratories around the world that are able to identify antimicrobial-resistant organisms, enhance biosecurity and biosafety, encourage the elimination of diseases spreading from animals to humans and improve access to vaccinations.

The Agenda is improving detection through improved biosurveilance and diagnostic tests and is also funding the placement of epidemiologists around the world.

In addition, the Agenda is working to set in place a coordinated response to any threats of infectious disease outbreaks.
Most of the efforts that organizations, such as the World Health Organization, are involved with laboratory practices. By providing safe and secure laboratories, much of the spread of infectious diseases is reduced. In addition, through increased training and education, many of the threats can be reduced.

Although biosecurity is often not a focus of national security, diseases can eradicate the human population as effectively as man-made weapons. By working to improve the resources available as well as improve worldwide practices of prevention, detection and response, much of the biosecurity risk can be eliminated.

– Lily Tyson

Sources: World Health Organization 1, World Health Organization 2
Photo: Science Media Centre