The spread of Zika virus across Latin America, with its apparent tragic consequences for the babies of infected pregnant women, has parallels with the emergence of Aids more than 30 years ago, according to a senior epidemiologist on the frontline in Brazil.



Wilson Savino, director of the Oswaldo Cruz Institute in Rio de Janeiro, said the current state of scientific ignorance around the virus and its effects resembles that over HIV – the human immunodeficiency virus which gives rise to Aids – in the early 1980s.

“Back then, the scientific and medical community did not know what was going on until many people had died and considerable research had been undertaken,” said Savino. “Then it turned out to be a global health issue. In Brazil, although we have identified the Zika virus, we don’t know much about it compared with dengue or yellow fever. The degree of ignorance is comparable to what we faced 32 years ago.

“This is a major health incident in the history of Brazil. We face a very serious problem for which scientific knowledge is far from sufficient. The scientific community has the responsibility to discover as much as possible as rapidly as possible.”



Savino is one of three senior Brazilian researchers and officials who were asked by the Guardian to shed light on how a disease initially classified as harmless came to be implicated in the outbreak of microcephaly – the birth of babies with small heads and underdeveloped brains – which has now been designated by the World Health Organisation as a public health emergency of international concern.

Zika virus was first identified in Uganda in 1947. It is thought to have arrived in Brazil in 2014, possibly with visitors to the World Cup. There are now an estimated 1.5 million cases of Zika infection and the number is growing fast, though nobody knows how widespread the disease is because there are no symptoms in about 80% of cases.

In the rest, it can lead to fever, aching joints, muscle pains, sore eyes, itching skin and rashes and is now suspected as a cause of the spike in microcephaly cases in Brazil, although without scientific certainty. Suspected cases of microcephaly have risen from fewer than 150 in 2014 to 3,670 in the past three months, but sceptics suggest this may simply reflect a previous under-reporting of abnormalities, which are also found in countries without Zika.

Gabrielly Santana da Paz holds her child who suffers from microcephaly at the Oswaldo Cruz hospital in north-eastern Brazil. Photograph: Xinhua/Rex/Shutterstock

“The fear is real. The scare is real,” said Gúbio Soares Campos, a virologist at the Biology Institute of the Federal University of Bahia who was one of two researchers who first identified Zika in Brazil last April. “People have to really be careful right now because we do not yet know whether there will be other major consequences.”

Pregnant women needed to be very vigilant, avoiding mosquito bites especially in the first months of pregnancy, he said. “We can’t confirm yet that only the Aedes aegypti is transmitting the disease. This needs to be investigated and scientifically proven. Those who affirm this are wrong, because the truth is that we don’t know. It could be transmitted by other mosquitoes,” he said.

Health officials needed to wage war on mosquitoes on the streets, with information to the public and a campaign to reduce the numbers of insects and larvae, said Soares Campos. A blood test for infection and antiviral drugs that pregnant women could take must be investigated.

Scientists need to know whether it is possible to get Zika more than once, or if one infection conveys lasting immunity. “It’s very important to know this now, more important than the vaccine,” he said. “ If people develop immunity, then most of the population will already be protected if there is another outbreak. This would put the government and the people a lot more at ease.”

He was critical of the Brazilian government, which had been slow to fund research, particularly into ways of controlling disease-transmitting mosquitoes. “There is too much bureaucracy. The Brazilian government needs to be more agile with this,” he said.

Claudio Maierovitch, director of the communicable disease surveillance department at the ministry of health, said that “we don’t have any doubt about the link between Zika and microcephaly.

Brazilian soldiers conduct an inspection for the Aedes aegypti mosquito on a street in Recife, Brazil, on Monday. Photograph: Ueslei Marcelino/Reuters

“The sudden increase in microcephaly happened exactly in the places where Zika had hit between seven and 10 months earlier. So the time frame fits. Also, the majority of women who have given birth to children with microcephaly have described the symptoms of Zika at the beginning of their pregnancies, such as skin rashes and fever.” Antibodies to the virus had also been found in infants born with microcephaly.

“The main thing now is to combat the mosquitoes,” he said. “This is being done with a huge national mobilisation, including state companies, government ministries, city mayors and the army. Basically, the risk is anything that collects still water in the open, be it rainwater, drinking water or something else. These receptacles need to be removed or covered.

“Water tanks need to be protected with lids or nets so that mosquitoes can’t lay eggs. If that is not possible, then larvicide should be applied to prevent them from attracting mosquitoes. This could apply to uncovered cisterns, pools, fountains in public parks and buildings that hold water without proper drainage. Even drinking water can be treated with larvicide.”

• This article was amended on 3 February 2016 to clarify the stated number of microcephaly incidents in Brazil as suspected cases, and to correct the number of such cases in the past three months.