KOCHI, India — The rare and deadly Nipah virus has emerged in southern India, killing at least 11 people and causing more than 25 others to be hospitalized. Although global health officials consider that, so far, to be a relatively small outbreak, they’re worried.

Nipah is on the World Health Organization’s priority list of emerging diseases that could cause a global pandemic, alongside Zika and Ebola.

“This is the first time we’ve seen the virus in south India,” says R.L. Sarita, the director of health services in the Indian state of Kerala. “And we want to make sure that it stays contained here.”
Those infected suffer a quick onset of symptoms, including fever, vomiting, disorientation, mental confusion, encephalitis and — in up to 70 percent of cases, depending on the strain — ultimately death. Here’s what we know, and don’t know, about this incurable disease:

How is the Nipah virus spread?
Several species of fruit bat that live throughout Asia carry Nipah. During outbreaks in Bangladesh from 2001 to 2007, most people contracted the virus by drinking raw date palm sap that virus-carrying fruit bats had also sipped and contaminated (SN: 12/19/09, p. 15).
Bats can also transmit Nipah to pigs and other livestock, which can then pass the infection onto humans. And humans can spread the virus through saliva and possibly other bodily fluids. One victim in the latest outbreak was a 31-year-old nurse who had been treating Nipah patients.

To find the source of this outbreak, health officials in India are testing local bats, livestock and food samples, including mangos that may have been bitten by bats, found in the home of a family that lost four members to Nipah.
How does the virus cause infection?
Nipah and its viral cousin Hendra latch onto a proteins called ephrin-B2 and ephrin-B3 on the surface of nerve cells and the endothelial cells lining blood and lymph vessels, researchers have found. Nipah can also invade lung and kidney cells.

Virologists who have studied Nipah’s behavior in animals think that in humans, it initially targets the respiratory system before spreading to the nervous system and brain. Most patients who die succumb to an inflammation of blood vessels and a swelling of the brain that occurs in the later stages of the disease.

Why are epidemiologists worried about Nipah?
“The No. 1 reason is that it’s just so lethal,” says Linfa Wang, who heads the emerging infectious diseases program at the Duke-NUS Medical School in Singapore. In fact, the villain virus in the 2011 film Contagion was based on Nipah (SN Online: 10/19/11).

Since the virus was first documented in 1998, there have been small, contained outbreaks almost every year in southeast Asia and Bangladesh.

But Nipah has the potential to spread farther — due to the fact that its fruit bat carriers live across a wide range extending from Australia to West Africa.

In addition, some strains are more lethal than others. An outbreak in Malaysia in 1999 was caused by a strain with a 30 percent mortality rate, while the Bangladesh outbreaks involved a different strain that killed 70 percent of infected humans. Scientists aren’t sure why the mortality rates are so different.

Is Nipah the next Ebola?
Not quite, says Stanford University epidemiologist Stephen Luby, who has studied the disease in Bangladesh, where there have been either outbreaks or sporadic cases almost every year since 2001. The two known Nipah strains currently circulating aren’t all that easy to transmit.
While the mortality rate for those infected can be high, infection is not all that common. Before this latest outbreak, about 300 deaths had been linked to Nipah, most of which occurred in Southeast Asia and Bangladesh. But the actual number could be higher, Luby says, with some cases going untested or unreported. Because the symptoms of Nipah infection are similar to those for other diseases, including encephalitis and the flu, cases may be misdiagnosed. India has only two main diagnostic laboratories, both in the central city of Pune, equipped to confirm Nipah infection.
“In order for a disease to spread globally, each person has to infect at least more than one person,” Luby says. But a person with Nipah tends to infect either zero or one other person, according to a 2009 study published online by the U.S. Centers for Disease Control and Prevention. By comparison, a person with measles can infect on average 10 others who aren’t vaccinated. And people who caught Ebola during the 2014 outbreak in West Africa tended to pass it on to between one and three others, PLOS Current Outbreaks reported in 2014.

But “anytime the virus is inside a human, it has the opportunity to evolve and adapt to that human-specific environment,” Luby says. The worst-case scenario is a future strain that can transmit more quickly or easily among humans, which is why the WHO and global health experts are urging more research into vaccines and treatments.

“I hope what we learned from the Ebola outbreak, is that if we have the ability to prepare, we should do that,” says Emily Gurley, an infectious disease epidemiologist at the Johns Hopkins Bloomberg School of Public Health in Baltimore

In fact, in response to this latest outbreak, the Coalition for Epidemic Preparedness Innovations (CEPI), a global alliance that formed last year to encourage and finance the development of vaccines, has announced that they will be granting $25 million to two American biotech companies to accelerate work on a Nipah vaccine. Researchers have tested experimental Nipah vaccines on animals, but have yet to conduct clinical trials.

Are fruit bats the problem?
Having been around for millions of years, bats have probably carried infectious diseases for nearly as long, Gurley says. Several bat species can carry viruses that are deadly to humans, including Ebola, Marburg, SARS and Nipah, without getting sick themselves (SN: 3/9/13, p. 10).

But scientists say that villainizing bats is not the answer. “They’re a crucial part of their ecosystems,” Gurley says. “They are also really important pollinators.”

Several factors have increased the chance of bat-borne viruses being passed humans, including development that has encroached on the bats’ natural habitats. “It used to be that these bats stayed far away from human populations,” Wang says.

Don’t count on a shady parking spot to save a child left in the back seat on a hot day.

A new analysis of temperatures inside parked cars reveals that a toddler in a sunbathed vehicle would reach lethal body temperatures faster than one left in the shade. But even in a shaded car, a child could die from overheating within a few hours, researchers report online May 23 in Temperature.

Researchers tracked temps inside three cars — a sedan, economy car and minivan — that were parked in the sun, and another three parked in the shade. Each car started at the outdoor air temperature or 29.4° Celsius, whichever was cooler. On days hotter than 38° C (about 100° Fahrenheit), it took an hour for the average ambient temperature inside the shaded vehicles to reach 38.3° C. For cars in the sun, the inside temperature hit a scorching 46.7° C in an hour, with surfaces such as steering wheels, dashboards and seat covers getting even hotter.
The researchers then simulated how the body temperature of a 2-year-old would increase under those conditions. On average, a toddler’s body would reach the potentially lethal temperature of 40° C (104° F) after about 1.4 hours in the sun and about 2.4 hours in the shade. It happened faster in some cars than others — a child left in a sunbaked sedan could die from overheating in just an hour.

On average, 37 children in the United States die from heatstroke inside vehicles each year, and in more than half of those cases, the children had simply been forgotten. Car or smartphone alerts reminding drivers to check the back seat could help prevent these deaths, says coauthor Jennifer Vanos, an extreme heat and public health researcher at the University of California, San Diego.

Baby planets growing in a disk of gas and dust around an infant star have been identified and weighed for the first time. In papers published June 13 in the Astrophysical Journal Letters, two teams of astronomers describe a new technique to observe the newborn planets with unprecedented precision.

One team, led by Richard Teague of the University of Michigan in Ann Arbor, found two protoplanets about the mass of Jupiter in orbit around a young star called HD 163296. The star is about 4 million years old and about 330 light-years from Earth. Another team led by Christophe Pinte of Monash University in Melbourne, Australia, spotted a third protoplanet about twice Jupiter’s mass in an even farther orbit around the same star.
Both groups used data from ALMA, the Atacama Large Millimeter/submillimeter Array network of radio telescopes in Chile. ALMA data had previously revealed gaps and rings in the disks around some young stars that may have been carved out by the gravity of protoplanets (SN Online: 11/6/14). But random fluctuations in the gas and dust can produce rings and spirals without planets.
Instead of relying on the disk’s shape to give young planets away, the two groups studied the motion of the gas. The teams independently developed a way to measure the gas velocity by watching the shift in the wavelength of light emitted by carbon monoxide molecules.
The gas motions were best explained by a planetary pull, Teague says. “It would have to be an extremely contrived scenario to say that it’s not a planet.”
Teague hopes to use the technique on dozens of other stars to see what kinds of protoplanets are most common.

“On its own, it’s hard to tell whether [this system is] an outlier or fairly typical,” he says. “The power here will be how we apply this technique to other systems.”

The global network of seafloor cables may be good for more than ferrying digital communication between continents. These fiber-optic cables could also serve as underwater earthquake detectors, researchers report online June 14 in Science.

“It’s a very exciting proposition,” says Barbara Romanowicz, a seismologist at the University of California, Berkeley and the Collège de France in Paris.

Almost all seismic stations around the world are based on land, leaving many oceanic earthquakes undetected. Harnessing the million-plus kilometers of underwater fiber-optic cables to monitor seafloor earthquakes would be “a great step forward” for studying Earth’s interior, Romanowicz says.
What’s more, quake-detecting cables could bolster tsunami alert systems. “The more [seismic] stations feeding into a tsunami warning system, the faster it can give a warning,” says study coauthor Richard Luckett, a seismologist at the British Geological Survey in Edinburgh.

To use a telecommunication cable as a seismic sensor, researchers inject light from a laser into one end of the optical fiber and monitor the light that exits the other end. When a seismic wave rattles the cable, it distorts the laser light travelling through it. By comparing the original laser signal with the light that exits the cable, researchers determine how much the beam was distorted along the way — and therefore the strength of the seismic wave that strummed the cable.

Combining measurements from multiple fiber-optic cables can triangulate the earthquake’s point of origin, explains study coauthor Giuseppe Marra, a frequency metrology researcher at the National Physical Laboratory in Teddington, England. Once researchers know the strength of a seismic wave when it passed the cable and where the wave started, they can determine the original earthquake’s magnitude.
Marra and colleagues tested their quake-detecting technique on both land-based and submarine fiber-optic cables. One 79-kilometer cable in southern England sensed vibrations from quakes originating in New Zealand and Japan that seismometers put at magnitude 7.9 and 6.9, respectively. Other land-based cables in the United Kingdom and Italy sensed a magnitude 7.3 quake that rocked the Iraq-Iran border last November. And an underwater cable that runs 96 kilometers from Sicily to Malta detected a magnitude 3.4 tremor emanating from the middle of the Mediterranean Sea last September. This seismic sensing technique still needs to be tested on longer cables that cross oceans, Marra says.

Fiber-optic cables that identify earthquakes far from land could provide new insight into geologic goings-on under the sea. For instance, better views of seafloor movements could help researchers understand how volcanism at mid-ocean ridges creates new oceanic crust, Luckett says (SN: 10/19/13, p. 22). Monitoring seafloor seismic activity could also help scientists study mantle plumes, upwellings of hot, buoyant rock within Earth’s mantle, Romanowicz says (SN: 10/22/11, p. 8).