Zika virus, as a member of the virus family Flaviviridae and the genus Flavivirus, transmitted by daytime-active Aedes mosquitoes. Its name comes from the Zika Forest of Uganda, where the virus was first isolated in 1947. 

According to the U.S. Centers for Disease Control and Prevention (CDC), Zika virus is related to dengue, yellow fever, Japanese encephalitis, and West Nile viruses.The infection, known as Zika fever, often causes no or only mild symptoms, similar to a mild form of dengue fever. In January 2016, the CDC issued travel guidance on affected countries, including the use of enhanced precautions, and guidelines for pregnant women including considering postponing travel.

In February 2016, some researcher believed that there is evidence to support that Zika fever in pregnant women can cause abnormal brain development in their fetuses by mother-to-child transmission, which may result in miscarriage or microcephaly.

However, recently a group of Argentine physicians challenged the connection between the Zika virus with the miscarriage. The group believed that the Zika virus is not to blame for the rise in microcephaly cases, but that a toxic larvicide introduced into Brazil's water supplies may be the real reason behind it.

According to the Physicians in Crop-Sprayed Towns (PCST), in 2014, a chemical larvicide that produces malformations in mosquitoes was injected into Brazil's water supplies in order to stop the development of mosquito larvae in drinking water tanks.  The group of Argentine doctors stated that during past Zika epidemics, there have not been any cases of microcephaly linked with the virus.

In fact, about 75 percent of the population in countries where Zika broke out had been infected by the mosquito-borne virus. For example, Colombia, where there are plenty of Zika cases, are no records of microcephaly linked to Zika. 

The Colombian president said that many of the country's citizens were infected with Zika but that there was not a single case of microcephaly. The record shows that 3,177 pregnant women in the country were infected with Zika, but these women all will have or already had healthy babies.

An aedes aegypti mosquito is pictured on a leaf in San Jose, Costa Rica Feb. 1, 2016 source: http://www.telesurtv.net/english/news/WHO-Dispels-Popular-Theories-about-the-Zika-Virus-20160220-0008.html

Photograph by Mario Tama Getty Images source: http://fortune.com/2016/02/16/monsanto-zika-virus-conspiracy/

The Polluter-Pays Principle (PPP)

The Polluter-Pays Principle (PPP)

The Polluter-Pays Principle (PPP) means that the polluter should bear the expenses of carrying out the pollution prevention and control measures, in order to ensure that the environment is in an acceptable state.

 Source: http://www.economicshelp.org/blog/6955/economics/polluter-pays-principle-ppp/

The polluter pays principle  (PPP) is a economic idea that firms or consumers should pay for the cost of the negative externality they create.

The polluter pays principle usually refers to the environmental costs. However, in the general cases, these environment cost could be extended to any external cost, whether than the private cost to the environment, but also the social cost of some goods are greater than the private cost.

This requires some authority or government agency to calculate our external costs and make sure that we pay the full social cost. Petrol tax cold be a good example for the polluter pays principles. When people purchase petrol, they will create the damages or pollution to the environment and the government will need to calculate the expense for the consumers.  The tax means the price we pay more closely reflects the social cost.

The polluter pays principle was incorporated into the 1992 Rio summit The declaration stated:

Principle 16: “National authorities should endeavor to promote the internalization of environmental costs and the use of economic instruments, taking into account the approach that the polluter should, in principle, bear the cost of pollution, with due regard to the public interest and without distorting international trade and investment.” 

Some of the environment issue are hard to be charged by the polluter pays principle. Green gas could be a example. Because the green gas has been slow to recognize the link to the climate change,  and the atmosphere is considered to be a global commons, the government could not find the polluter to pay the expense. Recently,  a new concept called carbon price could help the government to charge the firms.

Haze in Beijing, China 

Source: http://www.theguardian.com/environment/2012/jul/02/polluter-pays-climate-change