More than 5,000 pregnant Colombian women have been infected with the Zika virus, the country’s health authority has said, as the outbreak continues to spread across the Americas.

An epidemiology bulletin from Colombia’s national health institute said there were 31,555 cases of the mosquito-borne virus in the country, including 5,013 pregnant women. The virus is believed to be linked to a neurological birth defect known as microcephaly, in which babies are born with abnormally small heads and suffer incomplete brain development.

At the end of January, the Colombian health minister, Alejandro Gaviria, reported roughly 20,000 Zika infections, placing the country second only to Brazil in the severity of its outbreak. No figure for pregnant women was given at the time.



The World Health Organisation has said the virus is also suspected of being linked to the rare neurological disorder Guillain-Barré syndrome (GBS), in which the body’s immune system attacks part of the nervous system, causes gradual weakness in the legs, arms and upper body and sometimes leads to complete paralysis.

The WHO said in a weekly report published on Saturday: “In the context of the Zika virus outbreak, Brazil, Colombia, El Salvador, Suriname and Venezuela have reported an increase of GBS.”

It added: “The cause of the increase in GBS incidence observed in Brazil, Colombia, El Salvador and Suriname remains unknown, especially as dengue, chikungunya and Zika virus have all been circulating simultaneously in the Americas.”

Investigations continued to determine the cause, the WHO said, noting that there was no laboratory confirmation of Zika virus in patients with GBS in Colombia and El Salvador.

WHO officials said it was now critical to stop the spread of Zika.

“There are concerns that the Zika virus may spread globally to environments where mosquitoes can live and breed,” the organisation said.

The outbreak has already been declared a public health emergency of international concern, with US and UK health authorities warning pregnant women to avoid travelling to affected areas. All aircraft returning to the UK from affected countries are being sprayed with insecticide.

Around 220,000 soldiers were deployed across Brazil on Saturday in a massive campaign to raise awareness of the virus and offer advice on how to eliminate the Aedes aegypti mosquito that spreads it.

It has yet to be proven that Zika is linked to microcephaly or Guillain-Barré syndrome, but evidence is stacking up. Venezuela had reported 252 cases of Guillain-Barré occurring at the same time and place as Zika infections, the WHO said.



“Zika virus infection was confirmed for three of the GBS cases, including one fatal case,” it said.

Venezuela’s president, Nicolas Maduro, said on Thursday that three people had died of complications linked to the Zika virus and that suspected cases of Zika had risen to 5,221.

Even in the best of settings, 3-5% of Guillain-Barré patients die from complications, which can include paralysis of the muscles that control breathing, blood infection, lung clots or cardiac arrest, according to the WHO.

In French Polynesia, all 42 Guillain-Barré cases identified during the Zika virus outbreak in 2013-14 tested positive for dengue and Zika virus infection.

