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Eight Emerging Pathogens You Should Know About

These emerging trendsetters could pose huge human health risks, while research and development lag behind.

You’ll want to know about these hot new viruses in for 2016 — these emerging trendsetters, identified by the World Health Organization, could pose huge human health risks, while research and development lag behind. The organization is urging member nations and research institutions to prioritize these eight pathogens, and it warns that more are likely to come with annual review. Tongue-in-cheek comments aside, these conditions are of particular concern because few options are available for medical treatment beyond supportive care for infected patients, and that represents an unacceptable risk, particularly in regions of the world where poor sanitation, large numbers of travelers, and other factors can cause diseases to spread like wildfire.

Scientists, clinicians, public health officials, and other consultants met in Geneva to compile the list, consider known epidemics, potential threats, and current funding levels for various diseases — tuberculosis, for example, is not on the list because it’s already being heavily investigated — as they decided which infectious agents should be included.

1) Crimean Congo Hemorrhagic Fever

As the name suggests, this tick-borne illness has a wide home range, including Eastern Europe, the Middle East, Asia, and Africa. First identified in 1944, it can be deadly for both patients and health care personnel, with a 10 to 40 percent fatality rate, and few options are available when it comes to treatment and prevention — though pesticides are used and under consideration in some areas, despite their potential effects on humans and the environment.

After being bitten by an infected tick, the patient usually feels healthy for up to three days before becoming fatigued and developing a fever. Gradually, she also begins to show signs of mental health disturbance in addition to indicators that she’s slowly hemorrhaging, including bruising, marks around the eyes, dark stool, nosebleeds, and, as seen in the photo above, burst vessels in the eyes. The liver and other organs can start to fail before the patient ultimately dies, usually of respiratory arrest.

The anti-viral drug ribavirin works in some patients, but treatment options are primarily supportive in nature. Experiments with vaccines haven’t been very successful, and beyond that, the best options available include fluid replacement, supplemental nutrition, and keeping the patient warm and dry. Dedicating more funds to learning about the virus, its vectors, and treatment options could reduce the fatality rate.

2) Nipah

This virus is zoonotic, transmitted between animals and people. It’s a relatively new disease found in swine and human populations in 1998, when around 40 percent of infected patients died — and because many cultures consume pigs, this makes it easy for the virus to spread. People who farm and handle pigs can be prone to infection, as can people who eat infected meat or come into close contact with animals who carry the disease. A more well-known example of a zoonotic disease is avian influenza, which caused panic in Asia that led to slaughtering millions of animals — closer to home, a scare in the Midwest resulted in the deaths of 40 million poultry.

The natural reservoir of this encephalitic disease appears to be a fruit bat. Bats are common vectors of disease and viruses can exist at a background level in bat population for months or years before a confluence of perfect circumstances creates a flareup. Unfortunately, innocent bats are often persecuted along the way.

Humans infected with the virus sometimes exhibit no symptoms at all. Others develop respiratory problems and brain inflammation that can be fatal if care providers can’t treat them — even if people recover, they may have permanent health problems like speech or cognitive delays due to brain damage. The disease hasn’t taken hold with any major outbreaks since it was first identified, but it has periodically reappeared, ringing alarm bells that it could become more aggressive and catch people by surprise with no available treatments beyond comfort care.

3) Lassa Fever

This hemorrhagic fever might superficially look like Ebola, but it’s distinctly different, and the virus that caused it proved quite elusive to track down. It was first spotted in 1969 in Lassa, Nigeria, and while it hasn’t been involved in huge outbreaks, it does make regular reappearances, including in people who have traveled to Nigeria and returned home without realizing that they’re carrying a virus with them. Rodents like rats tend to be responsible, which is how it originated in Nigeria, with patients eating food contaminated with rat urine and feces, but it doesn’t spread as readily between people.

Like other hemorrhagic fevers, this illness has an incubation period followed by lethargy and increasing temperature, with growing signs of internal bleeding. The patient may experience red spots and bruises across the body, and her internal organs can start to fail. People who come into close contact with the patient’s body fluids can also get infected, triggering a cascade effect across a hospital, clinic, or community. Many patients have mild or no symptoms and thus fly under the radar, with only severe cases making it into hospitals and clinics.

Thankfully, this disease is much more survivable than some of its cousins. Roughly 99 percent of infected patients recover, and while it is a regular visitor to Western Africa, it doesn’t shut down entire villages like Ebola or other severe infections. That said, no distinct treatments are available beyond ribavirin early in infection, and in highly virulent cases, care providers may have few options between providing supportive care and waiting — which is a problem, because if Lassa’s virulence increases and it spreads, it could be responsible for an outbreak that would be hard to manage.

4) Ebola Virus Disease

Discovered in 1976 in Western Africa, Ebola made big headlines in 2014 with a massive outbreak spanning across multiple countries and killing thousands of people. Travelers also brought the virus into the United States and Europe. The outbreak highlighted the fact that while the virus occurs regularly in Africa and is known to be a recurring problem, no treatments are available, including vaccines to prevent infection. The fatality rate can vary widely depending on location and strain, with some outbreaks killing 100 percent of known patients, while others are much more conservative. As West Africa develops and more people move in and out of the region, the risk that Ebola will spread is more serious, and as this outbreak showed, it moves like wildfire when no treatments are available.

The highly infectious disease is also a hemorrhagic fever, causing patients to develop fever and headaches around three days after infection before they become progressively worse, with vomiting, diarrhea, and liver/kidney damage. Eventually, some patients can develop the internal bleeding that has made Ebola so famous, sending their organs into failure and causing death from heart or respiratory failure as their organs overload.

Keeping patients hydrated with fluids is key to cases in which they’ve recovered. Infected people lose fluids so rapidly from diarrhea and vomiting that they can develop dangerously low blood pressure, and with no approved treatments — a vaccine is in development — on the market, doctors and nurses have to resort to managing the symptoms as best they can.

5) MERS Coronavirus Disease

Middle East Respiratory Syndrome first appeared in Saudi Arabia in 2012, and it’s part of a large family of diseases of public concern because of their aggressive effects on the respiratory system — SARS is another well known example, and in fact, it’s also on the list. Patients infected with the virus usually experience fevers and fatigue before showing respiratory symptoms like coughing and difficulty breathing, which can turn into pneumonia. Some patients also develop gastrointestinal distress, usually manifesting as diarrhea. Roughly one third die, illustrating that the infection can be highly dangerous.

The disease is particularly aggressive in older adults and those with weakened immune systems due to cancer, underlying infections, or immunosuppressant drugs. In addition, people with a history of smoking or lung disease are more at risk of serious complications. Epidemiology suggests that it originated in bats before moving to camels, manifesting as a zoonotic disease that affects humans, but doesn’t spread well from person to person unless people care for infected patients without protection.

No specific treatments are available to manage this illness, beyond controlling symptoms. In patients with mild cases, rest and fluids can be sufficient. For those on the other end of the spectrum, mechanical ventilation and fluid replacement could be required. If MERS mutates and becomes capable of spreading easily in a human population, it could represent a serious public health threat.

6) Marburg

Consider Marburg Ebola’s lesser-known cousin. This viral hemorrhagic fever, named for the German town where it first appeared in 1967 among people exposed to monkeys — another argument for not using primates in research — causes symptoms similar to those seen in Ebola patients, but it hasn’t spawned outbreaks on the scale of those seen in Africa. It’s extremely rare and appears to live in fruit bat populations in Africa — the infected monkeys had come from the region, and other outbreaks have occurred in nations like Angola and Kenya, where patients often interacted with bats because they were working in mines.

It can be quite virulent, and has an extremely rapid onset and progression. After exposure, patients become quite ill with headaches and joint pain before experiencing severe bleeding within the first week. If fluid loss from bleeding and diarrhea cannot be controlled, the patient’s blood pressure can drop to a fatal point — otherwise, the disease can cause organ failure, usually in the liver or kidneys, which leads to death. Direct contact with infected blood and tissue of humans and animals is usually the cause, and while outbreaks have been controlled in the past, that doesn’t mean it doesn’t pose a threat in the future — if Marburg becomes more aggressive or finds the perfect vector, like Ebola did in 2014, it could become a monster.

7) SARS Coronavirus Diseases

Severe Acute Respiratory Syndrome (SARS) was definitively linked to a coronavirus in 2003, after a significant outbreak in Asia. Patients typically develop what might feel like a regular cold first, complaining of headaches and joint pain, before experiencing serious respiratory symptoms like coughing, pneumonia, and difficulty breathing. If the disease can’t be controlled, the patient can die of respiratory arrest, which occurs in around 10 percent of cases, though the fatality rate is much higher in older adults. After the abrupt outbreak in 2003, SARS hasn’t been seen again.

Lulls like this are common with infectious disease, where a set of unusual circumstances allows a virus to bloom, and then it fades away again. However, that doesn’t mean SARS is gone. The coronavirus that causes it is still lurking in the environment, most probably in an animal population, and in the right circumstances of environmental stress, it could return. No treatment or prevention is available, which means that if it arises again, doctors will be working from scratch. This concerns the World Health Organization, hence the inclusion on the list — given the rapid spread and nature of the infection, the agency wants to be prepared if it appears again. Research on this coronavirus will also provide insight into related diseases.

8) Rift Valley Fever

Kenya’s Rift Valley is stunning, with a rich cultural history — and part of that history includes this disease, which is at least as old at the 19th century. The zoonotic disease spreads readily in animal populations and more slowly to humans, but the reason it poses a particular concern is that it drifts, happily showing up in locations all over the world far from its native stomping grounds. Its ability to manifest in countries previously thought free of the disease is especially worrying in light of the fact that it’s not fully understood and care providers have limited treatment options available, so a large outbreak could quickly get out of control.

Some patients experience the trademark fever the disease is known for, but recover reasonably quickly. Others can develop brain infections with severe complications including loss of sight, cognitive delays, and mood changes. Hemorrhagic cases are at a roughly 50 percent chance of death (overall case fatality rate is less than 1%), and if RVF ever manages to become more adroit at spreading in human populations, that fatality rate could increase. Patient contract the virus from handling infected animals, and when outbreaks do occur, quarantine can include mass slaughter and isolation of herds, which can be economically devastating in small communities in addition to tragic for farm animals.

WHO will no doubt be adding diseases to its list year by year in response to emerging trends in epidemiology as well as developments in research. In the future, these diseases may be highly manageable and quite rare — but until now, they post threats ranging from looming to quietly bubbling in the background, and public health officials want to strike sooner rather than later.

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