Sunday, 22 October 2017

Outbreak of Marburg Virus thought to have killed at least two in Kween District, Uganda.

Two people have died and two more are sick in an of Marburg Virus, a form of hemorrhagic fever similar to Ebola, in the Kween District of eastern Uganda. The alarm was raised after a 50-year-old woman died in a health clinic on 11 October 2017, of a fever combined with extensive bleeding and diarrhoea. Blood samples collected from the patient were sent for testing, and were confirmed to contain the Marburg Virus on 17 October. An investigation found that the woman's brother had died of a similar fever three weeks earlier, in what is thought to be an almost certain second case of the disease, as the man is known to have been a hunter who operated in an area with caves home to Fruit Bats of the genus Rousettus, the natural hosts of the Virus. 

Artificially coloured SEM image of the Marburg Virus. BSIP/UIG/Getty Images.

Marburg Virus is a form of Filovirus, the group of Bat-infecting RNA Viruses that also includes Ebola. It takes its name from the German city of Marburg, where the first outbreak was recorded in 1967, among workers that had been exposed to infected Monkey tissue, seven of whom died. Despite this European discovery, the Virus is now recognised as being endemic to tropical Africa, where it occasionally spreads from its usual Bat hosts to Human or other Primate hosts, resulting in short-lived but extremely lethal outbreaks.

Zoonotic diseases (diseases in which the pathogen usually infects an animal host, but which occasionally spreads to Humans) can be particularly dangerous, as Humans are not part of their natural life-cycle, with the effect that they are not under evolutionary pressure to keep Human hosts alive in order to perpetuate themselves. Such diseases typically have short duration and a high fatality rate, though epidemics usually burn out quickly.

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Asteroid 2011 UG20 passes the Earth.

Asteroid 2011 UG20 passed by the Earth at a distance of about 10 222 000 km (26.6 times the average distance between the Earth and the Moon, or 6.83% of the distance between the Earth and the Sun), slightly after 7.15 pm GMT on Sunday 15 October 2017. There was no danger of the asteroid hitting us, though were it to do so it would have presented a significant threat. 2011 UG20 has an estimated equivalent diameter of 99-310 m (i.e. it is estimated that a spherical object with the same volume would be 99-310 m in diameter), and an object of this size would be predicted to be capable of passing through the Earth's atmosphere relatively intact, impacting the ground directly with an explosion that would be 225-88 000 times as powerful as the Hiroshima bomb. Such an impact would result in an impact crater 1-5 km in diameter and devastation on a global scale, as well as climatic effects that would last years or even decades.

The calculated orbit of 2011 UG20. Minor Planet Center.

2011 UG20 was discovered on 18 October 2011 by the University of Arizona's Catalina Sky Survey, which is located in the Catalina Mountains north of Tucson. The designation 2011 UG20 implies that it was the 507th asteroid (asteroid G20) discovered in the second half of October 2011 (period 2011 U).

2011 UG20 has a 436 day orbital period and an eccentric orbit tilted at an angle of 19.0° to the plane of the Solar System, which takes it from 0.35 AU from the Sun (i.e. 35% of he average distance at which the Earth orbits the Sun, somewhat less the distance at which the planet Mercury orbits the Sun) to 1.89 AU from the Sun (i.e. 1.89% of the average distance at which the Earth orbits the Sun, and more distant from the Sun than the planet Mars). It is therefore classed as an Apollo Group Asteroid (an asteroid that is on average further from the Sun than the Earth, but which does get closer). This means that close encounters between the asteroid and Earth are extremely common, with the last having occurred in June 2014 and the next predicted in May 2020. As an asteroid probably larger than 150 m in diameter that occasionally comes within 0.05 AU of the Earth, 2011 UG20 is also classified as a Potentially Hazardous Asteroid.

2011 UG20 also has frequent close encounters with the planets Mercury, which it is thought to have last passed in October 2010, and is next predicted to pass in August 2034, and Venus, which it last came close to in November 2005 and is next predicted to pass in December 2024. Asteroids which make close passes to multiple planets are considered to be in unstable orbits, and are often eventually knocked out of these orbits by these encounters, either being knocked onto a new, more stable orbit, dropped into the Sun, knocked out of the Solar System or occasionally colliding with a planet.

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Four dead and ten missing following landslide at construction site in Penang State, Malaysia.

Four workers have been confirmed dead, two more have been injured, and another ten are missing following a construction site in George Town, the capital of Penang State in northeast Peninsula Malaysia, on Saturday 21 October 2017. The names of the dead men have not been released, but three of them have been identified as Bangladeshi nationals. All of the workers at the site are understood to have been male, with the majority having been Bangladeshi or Indonesian nationals, along with a Pakistani, a Rohingya, and a single Malay, identified as Yuan Kuok Wern, 27, the site supervisor. The are where the men were working is reported to be covered by a layer of mud and debris up to 35 m deep, which covers an area of about 160 m². Rescue efforts are being led by specialist search teams equipped with sniffer Dogs.

Onlookers watching rescue operations at the scene of the 21 October 2017 George Town landslide. Lai Seng Sin/Reuters.

The incident happened at about 8.50 am local time, when a 10 metre section of hillslope collapsed onto the construction site. The cause of the event is as yet unclear, but the area has been suffering an exceptionally wet rainy season, with numerous floods and related occurrences. Landslides are a common problem after severe weather events, as excess pore water pressure can overcome cohesion in soil and sediments, allowing them to flow like liquids. Malaysia has become increasingly landslip-prone in recent years due to extensive deforestation, which leaves soil exposed to heavy tropical rainfall. Concerns have also been raised about the large number of construction sites on steep hillslopes in urban areas, where workers are particularly vulnerable to landslip events during the rainy season.

Penang has suffered a series of weather-related incidents this rainy season, including the worst flooding in fifteen years and a series of landslides. The state has a wet tropical climate with two distinct rainy seasons (common close to the equator, where the Sun is highest overhead around the equinoxes and lowest on the horizons around the solstices). These run from April to May and September to November, with peak rains in September and October.

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Saturday, 21 October 2017

Wildfires kill 43 in Portugal.

Forty three people have been confirmed dead and a further 71 have been injured as a series of wildfires have swept across northern and central Portugal this week. The majority of those who have died have done so in their cars, trying to escape from raging forest fires on country roads. Over 600 separate fires have been reported, the second major outbreak of such fires this year, after a series of fires in June killed 64 people and injured over 250 more in the central Pedrogao Grande Region. At least four people have died in similar fires in neighbouring Spain this week.

 Forest fire in Portugal earlier this week. APTN.

The fires are reported to have a number of different causes, including in some cases deliberate arson, and have been made much worse by both a prolonged heatwave in Portugal. which has dried out vegetation making it vulnerable to fires, and high winds associated with Hurricane Ophelia which have fanned the blazes and helped them to spread rapidly. However the fires appear to have been worst not in areas of natural woodland, but in the countries extensive plantation forests (i.e. forests of planted trees grown for the value of their timber), with the most severe fires occurring in areas of Pine and, particularly, Eucalyptus cultivation.

Clouds of thick smoke from the forest fires above the town of Marinha Grande in the Leiria District of Portugal earlier this week. João Pinto/Severe Weather Europe.

Eucalyptus, or Gum Trees, are fast growing members of the Myrtle Family, Myrtaceae, native to Australia but now grown extensively for their timber in many other parts of the world. They are valued for their fast growth, enabling them to produce much timber quickly, However they dominate ecosystems in which they become established, causing a variety of problems both for native plants and animals, as Human residents. The trees produce large amounts of volatile terpanoids which suppress the growth of other plants, and consume large amounts of water, lowering the water table in areas where they become established. The trees also shed branches regularly, as well as leaves and strips of bark, creating a dry environment littered with dry plant material where wildfires quickly become established. The terpinoids in the wood of Eucalyptus cause these forests to burn readily, typically at a tempereature about 30 °C higher than other forest fires, which can kill specie such as Oak, which can often survive fires. This increases the ecological dominance of the Eucalyptus, as, while the trees are killed by the fires, the seed pods can survive and rapidly germinate after fires, which since the trees grow quickly, enables them to quickly claim the newly available land.

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Fireball over Long Island, New York.

The American Meteor Society has received reports of a bright fireball meteor being seen over Long Island, New York, at about 3.00 pm, Eastern Daylight Time (about 7.00 pm GMT), on Wednesday 18 October 2017. The majority of the sightings came from New York and New Jersey, though reports have come from Connecticut, Delaware, Rhode Island, Pennsylvania, Massachusetts, Maryland and New Hampshire as well. A fireball is defined as a meteor (shooting star) brighter than the planet Venus. These are typically caused by pieces of rock burning up in the atmosphere, but can be the result of man-made space-junk burning up on re-entry.

The 18 October 2017 fireball meteor seen from Connecticut. News 12 Connecticut.

The meteor was seen to move from northwest to southeast, entering the atmosphere over Connecticut or Long Island and terminating over the Atlantic Ocean (such meteors typically terminate many kilometres above the Earth's surface in an explosion caused by friction with the Earth's atmosphere). 

The estimated trajectory of the 18 October 2017 fireball meteor. American Meteor Society.

Objects of this size probably enter the Earth's atmosphere several times a year, though unless they do so over populated areas they are unlikely to be noticed. They are officially described as fireballs if they produce a light brighter than the planet Venus. It is possible, though unlikely, that this object will have produced meteorites that reached the surface (an object visible in the sky is a meteor, a rock that falls from the sky and can be physically held and examined is a meteorite), though most meteorites come from larger objects that penetrate further into the atmosphere before exploding, and therefore have a better chance of producing fragments that reach the surface.

Witness reports can help astronomers to understand these events. If you witnessed this fireball you can report it to the American Meteor Society here.  

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Eurypeza aurora: A new species of Scarab Beetle from Nairobi, Kenya.

Scarab Beetles, Scarabeidae, are a large and diverse group, containing about 30 000 known species from around the world. These Beetles are typically large and robust, and often with a metallic colouration. Many Scarab Beetles are excellent diggers, and many of these digging Scarabs share a habit of burying their eggs with a supply of dung to feed their young, gaining them the name Dung Beetles, though others lay their eggs on carrion, decaying plant matter, or in some cases living plants.

In a paper published in the journal Zootaxa on 18 October 2017 Ruchard Sehnal of the Department of Zoology and Fisheries, at the Czech University of Life Sciences Prague, describe a new species of Scarab from Kenya.

The new species is placed in the genus Eurypeza, which currently contains a single species from Somalia, and given the specific name aurora:, meaning Morning Star. The species is described from a single male specimen collected from the town of Salama in the Nairobi Metropolitan Region. It is an elongate Scarab, about 9.6 mm in length, with a reddish-brown head and black body, though this is covered in yellowish white hairs giving it a brownish appearance.

Eurypeza aurora, male in dorsal view. Scale bar is 1 mm. Sehnal (2017).

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Bacterial infection kills 125 000 Salmon at Scottish Fish farms.

Around 125 000 Salmon have died following an outbreak of the Bacterium Pasteurella skyensis at two Fish farms in Loch Erisort on the island of Lewis in the Outer Hebrides, off the west coast of Scotland since August 2017. The outbreak has claimed the lives of about 500 tonnes of Fish at the Marine Harvest operated farms, prompting complaints from local residents about the scent of decaying Fish.

A Salmon farm on Loch Erisort. WDC.

Pasteurella skyensis is a is a Gram-negative, facultatively anaerobic (i.e. capable of using oxygen, but not needing it), non-motile, rod-shaped, Gammaproteobacteria, related to other pathogenic Bacteria such as Vibrio cholerae (Cholera), Yersinia pestis (Plague) and Esherchia coli (food poisoning), first described in 2002 from farmed Salmon in Scotland. Fish infected with the disease become lethargic and lose their apatite, and frequently die. The disease spreads rapidly in Salmon farms, where the Fish are kept at far higher density than they would occur at in nature. 

Other species of Pasteurella cause infections in Cattle, Sheep, Cats, Dogs, Horses, Rabbits, Chickens, Ferrets, Deer, Sealions, Pigs, Geese, Buffalo, Tortoises, and Humans. Many of these Bacteria are part of the natural flora of the mouths of a range of animals, including domestic Cats and Dogs. Most Pasteurella infections are associated with animal bites, and can be treated fairly easily, but others cause more serious problems including hemorrhagic fevers in some domestic animals and a form of Cholera in Birds.

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