How climate change can create diseases?

 

Scientists use climate, population changes to predict diseases

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  A mosquito is seen under a microscope at the Greater Los Angeles County Vector Control District in Santa Fe Springs, California, U.S., May 18, 2016. Reuters

British scientists say they have developed a model that can predict outbreaks of zoonotic diseases – those such as Ebola and Zika that jump from animals to humans – based on changes in climate.

Describing their model as "a major improvement in our understanding of the spread of diseases from animals to people", the researchers said it could help governments prepare for and respond to disease outbreaks, and to factor in their risk when making policies that might affect the environment.

"Our model can help decision-makers assess the likely impact (on zoonotic disease) of any interventions or change in national or international government policies, such as the conversion of grasslands to agricultural lands," said Kate Jones, a professor who co-led the study at University College London's genetics, evolution and environment department.

The model also has the potential to look at the impact of global change on many diseases at once, she said.

Around 60 to 75 percent of emerging infectious diseases are so-called "zoonotic events", where animal diseases jump into people. Bats in particular are known to carry many zoonotic viruses.

The Ebola and Zika viruses, now well known, both originated in wild animals, as did many others including Rift Valley fever and Lassa fever that affect thousands already and are predicted to spread with changing environmental factors.

Jones' team used the locations of 408 known Lassa fever outbreaks in West Africa between 1967 and 2012 and the changes in land use and crop yields, temperature and rainfall, behavior and access to health care.

They also identified the sub-species of the multimammate rat that transmits Lassa virus to humans, to map its location against ecological factors.

The model was then developed using this information along with forecasts of climate change, future population density and land-use change.

"Our approach successfully predicts outbreaks of individual diseases by pairing the changes in the host's distribution as the environment changes with the mechanics of how that disease spreads from animals to people," said David Redding, who co-led the study.

"It allows us to calculate how often people are likely to come into contact with disease-carrying animals and their risk of the virus spilling over."

The team tested their new model using Lassa fever, a disease that is endemic across West Africa and is caused by a virus passing to people from rats. Like Ebola, Lassa causes hemorrhagic fever and can be fatal.

The study, published in the journal Methods in Ecology and Evolution, tested the model with Lassa and found the number of infected people will double to 406,000 by 2070 from some 195,000 due to climate change and a growing human population.

Bangladeshi infected with zika virus in singapore

 

 

Rising number of Bangladesh nationals infected with Zika in Singapore

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  A worker fogs the common area of a public housing estate at an area where locally transmitted Zika cases were discovered in Singapore, August 31, 2016. Reuters

More Bangladeshi workers have been tested positive for Zika virus in Singapore, raising the number of total cases to 19, the foreign ministry says.

Citing the Singapore Ministry of Heath, it said on Monday the patients were presented with “mild symptoms and have either recovered or (are) recovering.”

 
“They are being taken care of by the Ministry of Heath of Singapore,” it said in a statement.
 
“Bangladesh High Commission in Singapore has been in touch with the authorities of Singapore and are monitoring the situation."
 
Earlier, on Sep 1, the Bangladesh High Commission said they had found 10 Bangladesh nationals among the Zika-infected people in the city state.
 
Their names and identities have not been disclosed by the authorities for the sake of “privacy”.

The mosquito-borne infection is a cause of global concern for its link with microcephaly in which a baby is born with a small head.

Singapore recently reported the outbreak.

The situation has worsened fast, according to the US Centre for Disease Control that added the city state to its list of Zika-hit countries that pregnant women should avoid.

The Bangladesh mission issued an advisory for its nationals living in the Southeast Asian state and urged them to take precautionary measures to prevent mosquito breeding as vector control is critical in preventing transmission and reducing the risk of the virus.

The government also started compulsory airport screening for the passengers coming from Singapore to Dhaka.

The Aedes Aegypti mosquito that causes Zika also causes dengue fever which is prevalent in Bangladesh.

The Zika virus was first discovered in Uganda in 1947. The most common symptoms are fever, rash, joint pain, and conjunctivitis.

Zika virus in singapore

China intensified its checks on people and goods arriving from Singapore on Thursday, as an outbreak of the Zika virus in the small city-state was confirmed to have spread to at least one person in neighbouring Malaysia.

Authorities in Singapore, a leading regional financial centre and busy transit hub for people and cargo, said they had detected 151 people with the Zika virus, including a second pregnant woman, as of midday Thursday.

 
The first locally-transmitted Zika infection was reported on Saturday.
 
The government said earlier that half of the 115 cases reported previously were foreigners, mainly from China, India and Bangladesh, and most had already recovered.
 

Many of them are believed to be among the hundreds of thousands of migrant workers in Singapore's construction and marine industries.
 
Some new Zika cases have been found beyond the cluster area where the virus was initially detected.
 
"We have been tracking Zika for a while now, and knew it was only a matter of time before it reached Singapore," Prime Minister Lee Hsien Loong posted on his Facebook page. "Our best defense is to eradicate mosquitoes and destroy breeding habitats, all over Singapore."
 
Singapore is the only Asian country with active transmission of the mosquito-borne Zika virus, which in pregnant women can lead to serious birth defects.
 
Malaysia confirmed its first case of Zika infection, in a woman who had recently visited Singapore.
 
The United States, Australia and other countries have added Singapore to the growing list of places that pregnant women or those trying to conceive have been warned to avoid.
 
Hurricane in US complicates effort
 
Meanwhile, in south Florida, where nearly 50 cases of Zika have been reported in non-travellers, officials said they trapped the first mosquitoes that tested positive for the virus, further confirming reports of local US transmission.
 
"This find is disappointing, but not surprising," Florida Commissioner of Agriculture Adam Putnam said in a statement.
 
"Miami-Dade County, the City of Miami Beach, and state and federal partners will continue to work aggressively to prevent the spread of Zika," Putnam added.
 
That work is likely to be seriously hampered by a hurricane expected to hit Florida overnight, as high winds will make aerial insecticide spraying impossible and standing water in its aftermath will provide added mosquito breeding sites.
 

The Singapore outbreak and travel warnings come just two weeks before the Singapore F1 motor-racing Grand Prix, a major sporting and tourist draw. The race promoter said planning for the event is going ahead "as per normal".
 
Singapore's Tourism Board has said it is premature to consider any impact on the tourism industry, stressing the tropical city-state remains a "safe travel destination".
 
More than 55 million people pass through Singapore's Changi airport each year. Tourism arrivals topped 8 million in the first half of this year, around 1 million more than a year ago.
 
China is trade-dependent Singapore's top overseas market, and the Zika outbreak coincides with a dip in overall exports and slowing economic growth in both countries.
 
"If this continues, certainly it will have a negative impact, but it's hard to quantify in percentage terms or dollar value," said Francis Tan, an economist at United Overseas Bank in Singapore.
 
The Zika virus, which has spread through the Americas and the Caribbean since first being detected in Brazil late last year, is generally a mild disease but can cause microcephaly, a rare birth defect that can lead to serious developmental problems, and has also been linked to other severe foetal brain abnormalities.
 
The World Health Organisation has also linked Zika to Guillain-Barre, a rare neurological syndrome that causes temporary paralysis in adults.
 
Malaysia measures
 
The WHO, which declared Zika an international public health emergency, was holding a regular meeting of its Zika emergency committee on Thursdayto review the spread of the disease.
 
Malaysia, which has two land border crossings with Singapore, asked those going to the city-state to use mosquito repellent and to cover up to avoid bites. Tens of thousands of people travel between the two countries daily.
 
Indonesia has also stepped up protective measures following the Singapore outbreak, intensifying checks on arrivals from Singapore and posting paramedics at airports and border checkpoints.

             Zika is primarily spread by mosquitoes but can also be transmitted through unprotected sex with an infected person.

 
A case of suspected transmission through a blood transfusion in Brazil has raised questions about other ways it may be spread.
 
Several companies and government agencies are working to develop vaccines against Zika.
 
On Thursday, Japanese drugmaker Takeda Pharmaceuticals said it has joined the effort with help from US funding, and it expects to begin human testing next year.

zika virus is spreading all over the world

A relatively new mosquito-borne virus is prompting worldwide concern because of an alarming connection to a neurological birth disorder and the rapid spread of the virus across the globe.

The Zika virus, transmitted by the aggressive Aedes aegypti mosquito, has now spread to at least 25 countries. The Centers for Disease Control and Prevention is warning pregnant women against travel to those areas; health officials in several of those countries are telling female citizens to avoid becoming pregnant, in some cases for up to two years.

“That’s a pandemic in progress,” said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases at the National Institutes of Health. “It isn’t as if it’s turning around and dying out, it’s getting worse and worse as the days go by.”

The Zika virus is a flavivirus, part of the same family as yellow fever, West Nile, chikungunya and dengue. But unlike some of those viruses, there is no vaccine to prevent Zika or medicine to treat the infection.

Zika is commanding worldwide attention because of an alarming connection between the virus and microcephaly, a neurological disorder that results in babies being born with abnormally small heads. This causes severe developmental issues and sometimes death.

Since November, Brazil has seen nearly 4,000 cases of microcephaly in babies born to women who were infected with Zika during their pregnancies. To put that in perspective, there were only 146 cases in 2014. So far, 46 babies have died.

Other Latin American countries are now seeing cases in newborns as well, while in the United States one Hawaiian baby was born with microcephaly after his mother returned from Brazil. In Illinois, two pregnant women who traveled to Latin America have tested positive for the virus; health officials are monitoring their pregnancies.

The CDC is also asking OB-GYNs to review fetal ultrasounds and do maternal testing for any pregnant woman who has traveled to one of the 23 countries where Zika is currently active.

A smaller outbreak of Guillain-Barre syndrome, a rare autoimmune disorder that can lead to life-threatening paralysis, is also linked to Zika in a several countries.

How can we control zika virus?

On 4 May, The International Association of Ecology and Health (IAEH) and Ecohealth Alliance hosted a Zika virus webinar. The speakers were Dr. Felipe Naveca, Deputy Director of research at FIOCRUZ ILMD Amazon institute in Manaus, and Dr. Jay Varma, Deputy Director of Infectious Disease at the New York City Department of Health. You should be able to get the recorded webinar from the Ecohealth website, if you’re interested, but I wanted to post a quick summary for you here.

What is Zika virus?

Zika virus is an arbovirus (arthropod borne virus) named after the Zika Forest where the virus was first documented. Zika virus isn’t new globally – it was first documented in 1947 – but it recently reached the Americas, where it has quickly spread. In Brazil, where other arboviruses are also highly prevalent, the incidence of Zika virus falls between that of Chikungunya and Dengue. Zika virus is particularly concerning because infected pregnant women are more likely to have spontaneous abortions and infants carried full term have a high risk of microcephaly.

How is Zika virus transmitted?

Zika virus is predominantly transmitted among humans by Aedes mosquitoes. However, it can also be sexually transmitted from an infected man to his sexual partners. (I don’t know if it can go the other direction.) Blood transfusions from infected individuals also lead to transmission.

How can individuals and governments control the spread of Zika virus?  

In countries/states/provinces that do not yet have a Zika epidemic, the best form of control is prevention and monitoring. The CDC recommends avoiding travel to regions with Zika virus and practicing strict mosquito avoidance (e.g., long sleeves, repellent) if you must travel to those areas. That’s especially important if you’re pregnant. Men traveling to Zika-infected areas should use condoms for months after returning to avoid transmitting Zika to their partners. Also, anyone traveling to infected areas should avoid denoting blood and avoid being bitten by mosquitoes after returning home. Infection can be asymptomatic (you don’t know you’re infected), so these precautions should be taken even if you don’t think you’re sick.

There is no vaccine for Zika virus, so the best ways to control the spread in epidemic areas are safe sex, mosquito avoidance, and vector control. There are many methods for vector control, and using a collection of methods will likely be more effective in the long run than using a single method (=a strong unidirectional selection pressure). Promising and effective methods include eliminating standing water where mosquitoes can breed, infecting mosquitoes with Wolbachia, selectively applying pesticides to reduce mosquito populations, and using female mosquitoes to spread pyriproxyfen among oviposition sites.

Could Zika virus establish in the Northeastern US?

At this point, it’s unclear. The CDC updated its potential distribution map for Aedes aegyptiin the US to include regions much further north than the previous estimated distribution, but there aren’t necessarily any Aedes aegypti mosquitoes in those areas. There are otherAedes spp. mosquitoes in the Northeastern US, but at this point we don’t know if they would be competent Zika virus vectors or not. There’s also some question as to whether Culex mosquitoes can serve as vectors.

Does Zika virus infect any animals besides humans and mosquitoes?

Yes, Zika virus has been found in monkeys. But we still have very little information regarding zoonotic reservoirs for Zika virus.

The spreading map of zika virus

More than two billion people live in parts of the world where the Zika virus can spread, detailed maps published in the journal eLife show.

The Zika virus, which is spread by Aedes aegypti mosquitoes, triggered a global health emergency this year.

Last week the US Centers for Disease Control and Prevention confirmed that the virus causes severe birth defects.

The latest research showed mapping Zika was more complex than simply defining where the mosquito can survive.

One of the researchers, Dr Oliver Brady from the University of Oxford, told the BBC: “These are the first maps to come out that really use the data we have for Zika – earlier maps were based on Zika being like dengue or chikungunya.

“We are the first to add the very precise geographic and environmental conditions data we have on Zika.”

By learning where Zika could thrive the researchers could then predict where else may be affected. The researchers confirmed that large areas of South America, the focus of the current outbreak, are susceptible.

In total, 2.2 billion people live in areas defined as being “at risk”.

The infection is suspected of leading to thousands of babies being born with underdeveloped brains.

The at-risk zones in South America include long stretches of coastline as well as cities along the Amazon river and its tributaries snaking through the continent.

And in the US, Florida and Texas could sustain the infection when temperatures rise in summer.

Dr Brady added: “Mosquitoes are just one condition needed for Zika to spread but there’s a whole range of other ones.

“It needs to be warm enough for Zika to replicate inside the mosquito and for there to be a large enough [human] population to transmit it.”

Both Africa and Asia have large areas that could be susceptible to the virus, the researchers said.

wait for the announcement that 1/4 of the world should get a jab to “save” them from zika..