How Zika Virus Affects Unborn Babies

The World Health Organization said Thursday it expects three to four million cases of the Zika virus in the Americas, as fears mount over the rapid spread of the disease blamed for birth defects.

"We can expect three to four million cases of the Zika virus disease," said Marcos Espinal, the head of communicable diseases and health analysis at the WHO's regional office in the Americas.

Pregnant women are being urged to think twice before traveling to Latin American and Caribbean countries battling a rise in cases of microcephaly - a rare but brutal condition that shrinks the brains of unborn babies.

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The increase has coincided with an outbreak of the usually benign Zika virus. But the virus and the birth defects have not been scientifically linked, leaving many questions about what is happening to these children in the womb.

We asked the experts.

Q: What is microcephaly?

A: Babies with microcephaly have an abnormally small brain and skull for their age, in the womb or at birth, with varying degrees of brain damage as a result. It has many potential causes: infections, viruses, toxins or unknown genetic factors. - Jean-Francois Delfraissy of France's Inserm medical research institute.

Q: What are the consequences for the child?

A: In serious cases, early death. If the brain is under-developed, the body cannot function properly. In French Polynesia (one of the regions affected), these deformities have caused most of the babies to be stillborn, as the unborn infants simply cannot survive. - Andre Cabie, infections disease head at the University Hospital of Martinique.

A: For children who survive pregnancy and are born with microcephaly, the future is bleak. In the worst cases, children will be severely intellectually and physically handicapped. But even those less severely affected will likely struggle with psychomotor impairment - characterised by slow thought, speech and physical movements.

"It is a real tragedy." - Delfraissy Q: How does a virus affect an unborn child?

A: Many types of viral infections, such as rubella or cytomegalovirus, can cause physical deformities and intellectual deficiencies, especially during the first three months of pregnancy, when the vital organs are being formed. Viruses can travel through the placenta and infect the foetus directly, sometimes in the brain. - Delfraissy Viruses Pass Major Test to Enter Ranks of Living

Q: Why is microcephaly thought to be linked to Zika virus?

A: Microcephaly cases seem to have increased in the zone of the Zika outbreak. But also, the virus has been detected in stillborn children with microcephaly, as well as in the amniotic fluid.

The link between Zika and microcephaly is highly likely, but has not yet been proven scientifically. - Delfraissy A: This is a very new situation. Until a few months ago we did not know that Zika could cause congenital infections (which are present from birth) and microcephaly. It caught us all by surprise.

The evidence for the link is relatively strong, and considered strong enough to warrant public health measures.

- Laura Rodrigues of the London School of Hygiene and Tropical Medicine, via the Science Media Centre.

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Q: What are we doing to learn more?

A: Studies are underway in French Polynesia, where a Zika outbreak ocurred around the end of 2013 – beginning of 2014, to better understand how the virus may affect foetuses. In Martinique, where there is an outbreak right now, a trial group of pregnant women is being put together for study.

The difficulty is that people infected with the virus usually have no symptoms. A pregnant woman can thus be infected without knowing it. On the other hand, cases have been observed of pregnant women infected with Zika whose children did not develop microcephaly. - Cabie Q: Is Zika contagious between people?

A: There has been a case of sexual transmission, and theoretically transmission by transplantation or transfusion cannot be ruled out. The main route of infection is through mosquitoes. - Alain Kohl of the University of Glasgow's Centre for Virus Research.

Microcephaly is condition where a baby’s head is much smaller than expected.

Rarely has anyone looked at a potentially fatal infectious disease and exclaimed, "Now, that is a thing of beauty." One sculptor, however, has taken bacteria and viruses from their invisible world and placed them in ours.

Artist Luke Jerram has created a collection of glass artwork in the shape microorganisms -- bacteria and viruses no less that have the potential to infect or even kill human beings. By bringing these microscopic marauders to the light, Jerram demystifies these otherwise unknowable microorganisms. And using glass as a medium reinforces not only the fragility of the work, but also our own in the face of these diseases.

In this slide show, take a closer look at some of the highlights from Jerram's glass microbiology collection.

Turning HIV into a work of art is a seemingly impossible task. The virus is responsible for the deaths of an estimated 34 million people worldwide since the epidemic was first reported in 1981, according to UNAIDS, the joint United Nations Programme on HIV/AIDS.

The HIV virus sculpture was the first Jerram built for his collection.

If there's one disease that has plagued humankind throughout its history, it's malaria. In 2010, the World Health Organization estimated that more than 200 million people were infected with the disease, mostly in poverty-stricken regions of sub-Saharan Africa, but also parts of South America and Southeast Asia.

Malaria is transmitted through mosquito bites. Mosquito nets, insect repellant and pesticides are all effective means of prevention, but only for those with the available resources and access to afford them.

Looking at this spindly sculpture might make you the slightest bit queasy, and for good reason. E. coli is represented by this glass artwork. Although most E. coli strains are in fact harmless to humans, the strains we're most acquainted with are the ones that cause food poisoning.

This alien-looking sculpture is actually T4 Bacteriophage, a virus that targets E. coli bacteria.

Bacteriophages are small viruses that attach to the cell membrane of bacteria. The virus injects its DNA into the bacteria, which then produces replicas of the virus, filling the bacterium until it bursts.

If this model is giving you that nostalgic feeling of plagues past, you might not be surprised to find out that this work represents Severe acute respiratory syndrome, or SARS.

SARS made global headlines in 2003 when people in 37 countries and nearly reached pandemic levels. Although coverage of the illness was widely criticized for overstating the threat, nearly 9,000 were infected with the disease, with had a nearly 10 percent fatality rate.

Swine flu, shown here, was another contagious disease that drew global attention that Jerram selected for his exhibition, but this time it was personal. According to his website, Jerram came down with swine flu and constructed the sculpture "with a fever whilst swallowing my Tamiflu tablets every few hours."

Swine flu, or H1N1 strain of the influenza virus, made global headlines in 2009 as the next potential major flu epidemic. Though common among pigs, swine flu is rarely transmitted among humans. When it does infect a human, however, the symptoms associated with the virus, typical of other flu strains, are particularly acute.

Given just how common the Human Papilloma Virus (HPV) is among humans, you'd think this virus, pictured here, wouldn't be so controversial. In fact, it isn't, but the use of a vaccine to prevent the infection, which can lead to certain kinds of cancers in women.

Because the virus can be transmitted sexually, however, the idea of vaccinations, particularly compulsory ones for children -- the vaccine is in fact intended only for people 25 and younger -- generated a considerable pushback, despite the obvious benefits of the treatment.

Hand, foot and mouth disease might not get a lot of press, but these disease outbreaks are in fact fairly common, particularly among infants and children. Occasionally, they can be fatal. Symptoms are similar to the flu, with the exception of sores that can appear all over the body, but particularly the hands, feet and mouth of the carrier.

This final entry is an unrealized future mutation for a disease that doesn't exist yet. Look for it in a contaminated water main, food source or loving pet near you. (But seriously, don't.)