History

Recently we were shocked by an outbreak in Southern America with a ‘new’ strain of mosquito borne virus called Zika virus. The fact is Zika virus is not something new. It has been recognised and identified first in 1948 from aedes africanus mosquito in Zika forest in Uganda, hence the name Zika virus. From then on it had been identified in humans from Africa and Asia in 1950s. However it was first isolated in Malaysia in 1965, not in human, but in mosquito only. From then on, it was silent up till now.

What is Zika Virus?

Zika is a group of arbovirus which include flavivirus (dengue and Zika) and togavirus (chikugunya). These viruses shared the same vectors which is Aedes mosquito. It can be transmitted through mosquito bite, blood transfusion and vertical transmission which means from mother to child in utero.

The question is…

After so long in the world, Zika is believed to have more severe manifestation now. We witnessed the outbreak in France in 2013 then in Brazil in 2014-2015 and recently recorded cases in South East Asia in 2016. It is believed that Zika virus have spread following migration of people. It spread via the pathogens with different places and different epidemiology whether virus itself or the host. Thus, in a new environment, the zika virus mutated into a new genotype to adapt to new temperature and different weather.

In February 2016, the World Health Organisation (WHO) declared Zika virus to be a public health emergency of international concern.

Zika symptoms

Phases

Zika virus can manifest as early as three days after infection when fever starts to occur. Fever phase lasts usually up to 5 days (febrile phase). The problem with the Zika virus infection is that there is no well demarcated dateline or timing of when the complication phase will occur, but is estimated between the fifth day up till the fourth weeks. Then only the recovery phase can be seen from 4 weeks up to 3 months. This can be seen in one study done by Solomon et al in 2003 which showed that the antibody (CF IgM) can be detected after day 3, peak at day 7-14 and then starting to reduce thereafter (as published by a medical journal).

Symptoms

The symptoms of Zika virus infection varies as mild as low grade fever to a neurological manifestation and even congenital deformities. There is no classification of Zika virus. It can be acute infection, congenital infection or neurological type of infection. The neurological syndrome identified so far are Gullain barre syndrome, encephalitis,
meningitis, myelistis (antibody that attack the nerve cells causing damage at multiple level). The differential diagnoses are dengue fever and chikugunya infection.

How to protect oneself & remedies

Cleanliness

To fight zika virus, first we have to fight the vector which is responsible for the spread. Education on the importance of environment cleanliness to the public and creating public awareness may play a major role of preventing the spread. As simple as it sounds, it may not be easy to execute, and perhaps the hardest to achieve. Hard work and perseverance is needed to achieve such target and it involves multiple layers from the community as well as the health ministry.

Fogging

The mosquito fogging operations are aim to kill, or ‘knock-down’, any adult Aedes mosquitoes that may be carrying the virus.  The insecticide used in the mosquito fogging is a synthetic pyrethroid that is very similar to the insecticides used in most domestic insect spray cans that are found on supermarket shelves. The ‘fog’ is created by blasting the mixture of insecticide and water into very fine droplets through the fogging machine. The amount of insecticide in the fog is very small, and is dispersed at quantities that can only kill something as small as a mosquito, so at the concentrations used there will be no adverse health effects on people who are occasionally exposed to the fog. The type of insecticide being used in the fogger is also completely odourless.

Water supply

We can also treat the water supply using larvicides. Some studies even use a transgenesis which can alter the DNA of the virus so it will not spread any further. Wolbachia is another method available where bacteria is put into the insects (aedes mosquito in this case) to stop viral replication.

When to get a medical doctor’s assistance

The warning sign

Since there is no clear demarcation of differentiating Zika and dengue virus, it is advisable to get medical advice the moment you have fever for more than three days or anytime fever is associated with generalized body redness (rash). It is very important to get a proper history from you, for example the places you have been before the infection or fever occur. Even though not many Zika virus infections can cause death or as bad as dengue, it is still possible to cause debilitating symptoms and potential permanent brain damage, especially to children and in pregnant women. The limitation here is that the diagnostic tool may not be readily available in most of our hospitals, and even with the detection tools, it has a very strong association with other virus such as dengue and chikugunya as well. So it may not become conclusive as well.

The social impact

We are blessed that we do not have Zika outbreak here in Malaysia yet. Maybe we have it all along since it was detected in mosquito way back in 1965 but not really look into nowadays. If we look back at the outbreak in Brazil, it can spread to almost 30,000 people in just one week – such a big number in such a short time. Our medical facilities will be prepared and have a high suspicion of the disease should the outbreak occur. Furthermore, in view of strong association with Zika virus in new born babies in Brazil, this will definitely impact on the future generation and economic dynamic of the family involved.

The improvements we can make

Nowadays, our understanding of health has been astray from the root. Majority of us believed that rather than taking care of the cleanliness and maintain the health of the environment, people resort into treating with antibiotic and prophylaxis medications because that is easier to be done. I believe there is still a lot of study needed to be done such as better detection tools or vaccine against the Zika virus. But before we can come up with a better detection and treatment we have to really take care of our environment in the hope that we can prevent the disease. As we all know, prevention is always better than cure.