All About Scabies - III : How to prevent and control scabies

Prevention & Control of Scabies

When a person is infested with scabies mites the first time, symptoms may not appear for up to two months after being infested. However, an infested person can transmit scabies, even if they do not have symptoms. Scabies usually is passed by direct, prolonged skin-to-skin contact with an infested person. However, a person with crusted (Norwegian) scabies can spread the infestation by brief skin-to-skin contact or by exposure to bedding, clothing, or even furniture that he/she has used.

Scabies is prevented by avoiding direct skin-to-skin contact with an infested person or with items such as clothing or bedding used by an infested person. Scabies treatment usually is recommended for members of the same household, particularly for those who have had prolonged skin-to-skin contact. All household members and other potentially exposed persons should be treated at the same time as the infested person to prevent possible reexposure and reinfestation. Bedding and clothing worn or used next to the skin anytime during the 3 days before treatment should be machine washed and dried using the hot water and hot dryer cycles or be dry-cleaned. Items that cannot be dry-cleaned or laundered can be disinfested by storing in a closed plastic bag for several days to a week. Scabies mites generally do not survive more than 2 to 3 days away from human skin. Children and adults usually can return to child care, school, or work the day after treatment.

Persons with crusted (Norwegian) scabies and their close contacts, including household members, should be treated rapidly and aggressively to avoid outbreaks. Institutional outbreaks can be difficult to control and require a rapid, aggressive, and sustained response.

Rooms used by a patient with crusted scabies should be thoroughly cleaned and vacuumed after use. Environmental disinfestation using pesticide sprays or fogs generally is unnecessary and is discouraged.

All About Scabies - II : Diagnosis, symptoms and complications

Diagnosis of Scabies

Diagnosis of a scabies infestation usually is made based upon the customary appearance and distribution of the the rash and the presence of burrows.

Whenever possible, the diagnosis of scabies should be confirmed by identifying the mite or mite eggs or fecal matter (scybala). This can be done by carefully removing the mite from the end of its burrow using the tip of a needle or by obtaining a skin scraping to examine under a microscope for mites, eggs, or mite fecal matter (scybala). However, a person can still be infested even if mites, eggs, or fecal matter cannot be found; fewer then 10-15 mites may be present on an infested person who is otherwise healthy.

Symptoms

When a person is infested with scabies mites the first time, symptoms usually do not appear for up to two months (2-6 weeks) after being infested; however, an infested person still can spread scabies during this time even though he/she does not have symptoms.

If a person has had scabies before, symptoms appear much sooner (1-4 days) after exposure. An infested person can transmit scabies, even if they do not have symptoms, until they are successfully treated and the mites and eggs are destroyed.

Common Symptoms

The most common symptoms of scabies, itching and a skin rash, are caused by sensitization (a type of “allergic” reaction) to the proteins and feces of the parasite. Severe itching (pruritus), especially at night, is the earliest and most common symptom of scabies. A pimple-like (papular) itchy (pruritic) “scabies rash” is also common. Itching and rash may affect much of the body or be limited to common sites such as:

• between the fingers,
• wrist,
• elbow,
• armpit,
• penis,
• nipple,
• waist,
• buttocks,
• shoulder blades.

The head, face, neck, palms, and soles often are involved in infants and very young children, but usually not adults and older children.

Tiny burrows sometimes are seen on the skin; these are caused by the female scabies mite tunneling just beneath the surface of the skin. These burrows appear as tiny raised and crooked (serpiginous) grayish-white or skin-colored lines on the skin surface. Because mites are often few in number (only 10-15 mites per person), these burrows may be difficult to find. They are found most often in the webbing between the fingers, in the skin folds on the wrist, elbow, or knee, and on the penis, breast, or shoulder blades.

Possible Complications

The intense itching of scabies leads to scratching that can lead to skin sores. The sores sometimes become infected with bacteria on the skin, such as Staphylococcus aureus or beta-hemolytic streptococci. Sometimes the bacterial skin infection can lead an inflammation of the kidneys called post-streptococcal glomerulonephritis.

Crusted (Norwegian) scabies

Crusted (Norwegian) scabies is a severe form of scabies that can affect the elderly, persons who are immunocompromised, or persons who have conditions that prevent them from itching and/or scratching (spinal cord injury, paralysis, loss of sensation, mental debility). Crusted scabies is characterized by vesicles and thick crusts over the skin that can contain many mites. Itching (pruritus) may be absent in crusted scabies because of a patient’s altered immune status or neurological condition. Because they are infested with large numbers of mites (up to 2 million), persons with crusted scabies are very contagious. Persons with crusted scabies may not show the usual signs and symptoms of scabies such as the characteristic rash or itching (pruritus).

All About Scabies - I : How Scabies is Transmitted

Human scabies is caused by an infestation of the skin by the human itch mite (Sarcoptes scabiei var. hominis). The microscopic scabies mite burrows into the upper layer of the skin where it lives and lays its eggs. The most common symptoms of scabies are intense itching and a pimple-like skin rash. The scabies mite usually is spread by direct, prolonged, skin-to-skin contact with a person who has scabies.

Scabies occurs worldwide and affects people of all races and social classes. Scabies can spread rapidly under crowded conditions where close body contact is frequent. Institutions such as nursing homes, extended-care facilities, and prisons are often sites of scabies outbreaks.

How Scabies is Transmitted

Human scabies is caused by an infestation of the skin by the human itch mite (Sarcoptes scabiei var. hominis). The adult female scabies mites burrow into the upper layer of the skin (epidermis) where they live and deposit their eggs. The microscopic scabies mite almost always is passed by direct, prolonged, skin-to-skin contact with a person who already is infested. An infested person can spread scabies even if he or she has no symptoms. Humans are the source of infestation; animals do not spread human scabies.

Persons at Risk

Scabies can be passed easily by an infested person to his or her household members and sexual partners. Scabies in adults frequently is sexually acquired.

Scabies is a common condition found worldwide; it affects people of all races and social classes. Scabies can spread easily under crowded conditions where close body and skin contact is common. Institutions such as nursing homes, extended-care facilities, and prisons are often sites of scabies outbreaks. Child care facilities also are a common site of scabies infestations.

Crusted Scabies

Some immunocompromised, elderly, disabled, or debilitated persons are at risk for a severe form of scabies called crusted, or Norwegian, scabies. Persons with crusted scabies have thick crusts of skin that contain large numbers of scabies mites and eggs. The mites in crusted (Norwegian) scabies are not more virulent than in non-crusted scabies; however, they are much more numerous (up to 2 million per patient). Because they are infested with such large numbers of mites, persons with crusted (Norwegian) scabies are very contagious to other persons. In addition to spreading scabies through brief direct skin-to-skin contact, persons with crusted scabies can transmit scabies indirectly by shedding mites that contaminate items such as their clothing, bedding, and furniture. Persons with crusted scabies should receive quick and aggressive medical treatment for their infestation to prevent outbreaks of scabies.

World Health Organisation: New data highlight increases in hypertension, diabetes incidence

The World health statistics 2012 report puts the spotlight on the growing problem of the noncommunicable diseases burden.

One in three adults worldwide, according to the report, has raised blood pressure – a condition that causes around half of all deaths from stroke and heart disease. One in 10 adults has diabetes.

“This report is further evidence of the dramatic increase in the conditions that trigger heart disease and other chronic illnesses, particularly in low- and middle-income countries,” says Dr Margaret Chan, Director-General of WHO. “In some African countries, as much as half the adult population has high blood pressure.”

For the first time, the World Health Organization’s annual statistics report includes information from 194 countries on the percentage of men and women with raised blood pressure and blood glucose levels.

In high-income countries, widespread diagnosis and treatment with low-cost medication have significantly reduced mean blood pressure across populations – and this has contributed to a reduction in deaths from heart disease. In Africa, however, more than 40% (and up to 50%) of adults in many countries are estimated to have high blood pressure. Most of these people remain undiagnosed, although many of these cases could be treated with low-cost medications, which would significantly reduce the risk of death and disability from heart disease and stroke.

Also included for the first time in the World health statistics 2012 are data on people with raised blood glucose levels. While the global average prevalence is around 10%, up to one third of populations in some Pacific Island countries have this condition. Left untreated, diabetes can lead to cardiovascular disease, blindness and kidney failure.

Obesity another major issue

“In every region of the world, obesity doubled between 1980 and 2008,” says Dr Ties Boerma, Director of the Department of Health Statistics and Information Systems at WHO. “Today, half a billion people (12% of the world’s population) are considered obese.”

The highest obesity levels are in the WHO Region of the Americas (26% of adults) and the lowest in the WHO South-East Asia Region (3% obese). In all parts of the world, women are more likely to be obese than men, and thus at greater risk of diabetes, cardiovascular disease and some cancers.

Noncommunicable diseases currently cause almost two thirds of all deaths worldwide. Global concern about the rise in numbers of deaths from heart and lung disease, diabetes and cancer prompted the United Nations to hold a high-level meeting on noncommunicable diseases in New York in September 2011.

The World Health Assembly, to be held in Geneva from 21 to 26 May 2012, will review progress made since that meeting and agree on next steps. Work is currently under way to develop a global monitoring framework and a set of voluntary targets for prevention and control of these diseases.

Published annually by WHO, the World health statistics is the most comprehensive publication of health-related global statistics available. It contains data from 194 countries on a range of mortality, disease and health system indicators including life expectancy, illnesses and deaths from a range of diseases, health services and treatments, financial investment in health, as well as risk factors and behaviours that affect health.

Some key trends in this year’s report are:

• Maternal mortality: In 20 years, the number of maternal deaths has decreased from more than 540 000 deaths in 1990 to less than 290 000 in 2010 – a decline of 47%. One third of these maternal deaths occur in just two countries – India with 20% of the global total and Nigeria with 14%.
• 10 year trends for causes of child death: Data from the years 2000 to 2010 show how public health advancements have helped save children’s lives in the past decade. The world has made significant progress, having reduced the number of child deaths from almost 10 million children aged less than 5 years in 2000 to 7.6 million annual deaths in 2010. Declines in numbers of deaths from diarrhoeal disease and measles have been particularly striking.
• Death registration: Only 34 countries (representing 15% of the world’s population) produce high-quality cause-of-death data. In low and middle-income countries, less than 10% of deaths are registered.

NASA finds a new count of potentially hazardous asteroids

Observations from NASA's Wide-field Infrared Survey Explorer (WISE) have led to the best assessment yet of our solar system's population of potentially hazardous asteroids. Also known as "PHAs," these asteroids have orbits that come within five million miles (about eight million kilometers) of Earth, and they are big enough to survive passing through Earth's atmosphere and cause damage on a regional, or greater, scale.


The asteroid-hunting portion of the WISE mission, called NEOWISE, sampled 107 PHAs to make predictions about the population as a whole. Findings indicate there are roughly 4,700 PHAs, plus or minus 1,500, with diameters larger than 330 feet (about 100 meters). So far, an estimated 20 to 30 percent of these objects have been found.

In this simulated view of the near-Earth asteroid population, potentially hazardous asteroids (PHAs) are denoted in orange. Less dangerous near-Earth asteroids are blue. Earth's orbit is green. 

While previous estimates of PHAs predicted similar numbers, they were rough approximations. NEOWISE has generated a more credible estimate of the objects' total numbers and sizes. Because the WISE space telescope detected the infrared light, or heat, of asteroids, it was able to pick up both light and dark objects, resulting in a more representative look at the entire population.

"The NEOWISE analysis shows us we've made a good start at finding those objects that truly represent an impact hazard to Earth," said Lindley Johnson, program executive for the Near-Earth Object Observation Program at NASA Headquarters. "But we've many more to find, and it will take a concerted effort during the next couple of decades to find all of them that could do serious damage or be a mission destination in the future."

This orbit diagram illustrates the difference between a PHA and less hazardous near-Earth asteroids (NEA). 

The new analysis suggests that about twice as many PHAs as previously thought reside in low-inclination orbits, which are roughly aligned with the plane of Earth's orbit.

"Our team was surprised to find the overabundance of low-inclination PHAs," said Amy Mainzer, NEOWISE principal investigator, at NASA's Jet Propulsion Laboratory. "Because they will tend to make more close approaches to Earth, these targets can provide the best opportunities for the next generation of human and robotic exploration."

The NEOWISE analysis suggests a possible origin for the low-inclinaton PHAs: Many of them could have originated from a collision between two asteroids in the main belt lying between Mars and Jupiter. A larger body with a low-inclination orbit may have broken up in the main belt, causing some of the fragments to drift into orbits closer to Earth and eventually become PHAs.

The lower-inclination PHAs appear to be somewhat brighter and smaller than other near-Earth asteroids. The discovery that PHAs tend to be bright says something about their composition; they are more likely to be either stony, like granite, or metallic. This type of information is important in assessing the space rocks' potential hazards to Earth. The composition of the bodies would affect how quickly they might burn up in our atmosphere if an encounter were to take place.

"The NEOWISE project, which wasn't originally planned as part of WISE, has turned out to be a huge bonus," said Mainzer.  "Everything we can learn about these objects helps us understand their origins and fate."

Climate Change: NASA finds sea ice decline driving rise in Arctic air pollutants

 Drastic reductions in Arctic sea ice in the last decade
may be intensifying the chemical release of bromine into the
atmosphere, resulting in ground-level ozone depletion and the deposit
of toxic mercury in the Arctic, according to a new NASA-led study.

The connection between changes in the Arctic Ocean's ice cover and
bromine chemical processes is determined by the interaction between
the salt in sea ice, frigid temperatures and sunlight. When these
mix, the salty ice releases bromine into the air and starts a cascade
of chemical reactions called a "bromine explosion." These reactions
rapidly create more molecules of bromine monoxide in the atmosphere.
Bromine then reacts with a gaseous form of mercury, turning it into a
pollutant that falls to Earth's surface.

Bromine also can remove ozone from the lowest layer of the atmosphere,
the troposphere. Despite ozone's beneficial role blocking harmful
radiation in the stratosphere, ozone is a pollutant in the
ground-level troposphere.

A team from the United States, Canada, Germany, and the United
Kingdom, led by Son Nghiem of NASA's Jet Propulsion Laboratory in
Pasadena, Calif., produced the study, which has been accepted for
publication in the Journal of Geophysical Research- Atmospheres. The
team combined data from six NASA, European Space Agency and Canadian
Space Agency satellites, field observations and a model of how air
moves in the atmosphere to link Arctic sea ice changes to bromine
explosions over the Beaufort Sea, extending to the Amundsen Gulf in
the Canadian Arctic.

"Shrinking summer sea ice has drawn much attention to exploiting
Arctic resources and improving maritime trading routes," Nghiem said.
"But the change in sea ice composition also has impacts on the
environment. Changing conditions in the Arctic might increase bromine
explosions in the future."

The study was undertaken to better understand the fundamental nature
of bromine explosions, which first were observed in the Canadian
Arctic more than two decades ago. The team of scientists wanted to
find if the explosions occur in the troposphere or higher in the
stratosphere.

Nghiem's team used the topography of mountain ranges in Alaska and
Canada as a "ruler" to measure the altitude at which the explosions
took place. In the spring of 2008, satellites detected increased
concentrations of bromine, which were associated with a decrease of
gaseous mercury and ozone. After the researchers verified the
satellite observations with field measurements, they used an
atmospheric model to study how the wind transported the bromine
plumes across the Arctic.

The model, together with satellite observations, showed the Alaskan
Brooks Range and the Canadian Richardson and Mackenzie mountains
stopped bromine from moving into Alaska's interior. Since most of
these mountains are lower than 6,560 feet (2,000 meters), the
researchers determined the bromine explosion was confined to the
lower troposphere.

"If the bromine explosion had been in the stratosphere, 5 miles [8
kilometers] or higher above the ground, the mountains would not have
been able to stop it and the bromine would have been transported
inland," Nghiem said.

After the researchers found that bromine explosions occur in the
lowest level of the atmosphere, they could relate their origin to
sources on the surface. Their model, tracing air rising from the
salty ice, tied the bromine releases to recent changes in Arctic sea
ice that have led to a much saltier sea ice surface.

In March 2008, the extent of year-round perennial sea ice eclipsed the
50-year record low set in March 2007, shrinking by 386,100 square
miles (one million square kilometers) -- an area the size of Texas
and Arizona combined. Seasonal ice, which forms over the winter when
seawater freezes, now occupies the space of the lost perennial ice.
This younger ice is much saltier than its older counterpart because
it has not had time to undergo processes that drain its sea salts. It
also contains more frost flowers -- clumps of ice crystals up to four
times saltier than ocean waters -- providing more salt sources to
fuel bromine releases.

Nghiem said if sea ice continues to be dominated by younger saltier
ice, and Arctic extreme cold spells occur more often, bromine
explosions are likely to increase in the future.

Nghiem is leading an Arctic field campaign this month that will
provide new insights into bromine explosions and their impacts.
NASA's Bromine, Ozone, and Mercury Experiment (BROMEX) involves
international contributions by more than 20 organizations.