The Zika pandemic costs USD3.5 billion and it is estimated that each infected child will cost USD4 million. To prevent another costly epidemic, experts have created apps and methods to lookout for obscure viruses that can be spread among people through insects.

Many scientific papers have published about the next big illness and five viruses stand out to virologists and epidemiologists - although it is not guaranteed that it will become the next pandemic. But researchers say it is better to be safe than sorry.

1. Usutu

Usutu is an avian virus that is transmitted by Culex mosquitoes and is similar to a West Nile virus fever, causing neurological problems, fever and headaches. But most Usutu infections in humans usually end without symptoms. In a recent study, it showed that 6% of Italians have been recently infected by the virus, but did not know of it.

An unprecedented outbreak of Usutu among birds in Germany, France, Belgium, Hungary and the Netherlands was reported - it is at the state where the West Nile fever was, 20 years ago. What more, Usutu like the West Nile virus is an avian virus and could circulate easily to other parts of the world. Symptoms were reported to only occur in people with compromised immunity, but researchers state that the infection should not be underestimated.

2. Mayaro

Mayaro is similar to the chikungunya virus and that is why researchers predict it will amplify in humans - it can be transmitted efficiently by Aedes mosquitoes. The virus causes a disease that is clinically indistinguishable from the chikungunya virus: fever, rash, chills and joint pain that can last longer than a year.

It may not seem important which of these viruses circulate in the patient's body, but once vaccines against and drugs to treat Mayaro and chikungunya exist, they will likely be virus-specific. Both viruses were originally transmitted by forest mosquitoes, but chikungunya has made its way to urban mosquitoes - over 100,000 confirmed cases were reported in US by September 2016. This could happen to Mayaro as well.

3. Crimean-Congo haemorrhagic fever

This virus is transmitted by ticks, which spread infections slower than mosquitoes. However, fatality rates are at 40%. The virus has made its way from Africa to China in the past seven decades and the spread has accelerated in recent years. It infected up to 10,000 individuals in Turkey over13 years. In 2011, it was found in India and in September 2016, the first two cases were reported in Spain - one infected individual died.

The disease causes rash, fever and bleeding from any part of the body and the only treatment is the antiviral drug ribavirin, which is not very effective.

4. Rift Valley Fever

A Rift Valley infection may just cause fever and chills but it could be fatal to some as it could progress to a haemorrhagic disease, with abnormal bleeding or result in an inflammation of the brain. Half of the haemorrhagic cases from Rift Valley infection are fatal. There is no treatment.

The Rift Valley has been limited to Africa since the discovery of the virus in Kenya in the early 20th century. But in 2000, it travelled to the Arabian Peninsula and by 2014, tens of thousands of human cases and millions of livestock deaths resulting from the virus have been reported.

It is unknown if the virus is mutating to be more virulent or that diagnostic tools have improved resulting in an increase in numbers. The Rift Valley fever can be carried by over 30 species of mosquitoes and both domestic and wild animals can be a reservoir of the disease. Fortunately, a vaccine is under advanced developmental stages.

5. Chagas

Chagas is slightly different. It is a parasite that is transmitted by the "kissing bug" that has infected about 20 million people, mostly in South and Central America. In the future, it might infect 300,000 to 1 million people in the US.

Once infected, the parasite remains dormant inside the body until decades later, when very serious problems have been reported in 20% to 30% of the infected individuals - such as fatal heart arrhythmias. The disease can also be transmitted from mother-to-child and there is no standard diagnostic test nor a vaccine.

The parasite can be carried in many different species, but some scientists have expressed concern over the lack of attention from the scientific community. The WHO have said that Chagas is neglected probably because it is associated with poverty and marginalisation. MIMS

Read more:
As Zika-infected babies turn one in Brazil, WHO warns of virus epidemic in Asia
Zika virus may have been passed to man from sweat and tears of his father in the US
MOH: Eighth case of Zika virus infection reported in Malaysia