A female Aedes aegypti mosquito in the process of acquiring a blood meal from a human host. Photo/James Gathany/CDC
What is Zika?
Zika is the name of a virus discovered in a monkey in the Zika forest of Uganda in 1947. It is native to tropical Africa, southeast Asia and the Pacific Islands. But infections have exploded recently in Latin America and the Caribbean. It is spread through bites from the same kind of mosquitoes that can spread other tropical diseases, like Chikungunya and Dengue fever.
What are the symptoms?
Experts think that only about one in five people who are infected with the Zika virus develop any symptoms. For those that do, Zika illness usually involves fever, rash, joint pain, and red eyes which usually last no more than a week. There is no medicine or vaccine for it. Hospitalisations are rare and deaths from Zika have not been reported.
Why is it a concern?
There has been growing evidence linking Zika infection in pregnant women to a rare condition called microcephaly, in which the head is smaller than normal and the brain has not developed properly. US health officials are heading to Brazil, where there has been a recent spike in the birth defect, to further study the actual risk to pregnant women. More than 3,500 cases have been reported in Brazil since October.
The threat seems to be moving closer to the United States. Infections are occurring in Mexico and the kind of mosquitoes that can carry the virus are found along the southern United States. Experts think it’s likely the pests may end up spreading the virus in the US, though probably on a smaller scale than what has been seen in the tropics.
Where are
the latest cases?
Haiti’s Public Health Minister Florence Duperval Guillaume announced on Friday that there have been five confirmed cases of the Zika virus in Haiti. She says they are all in the area of Port-au-Prince, the overcrowded capital. Many Haitians live in shacks with little protection from mosquitoes.
A baby born in a hospital in Oahu, Hawaii, has tested positive for the mosquito-borne Zika virus, it was reported on Saturday. The US Centers for Disease Control and Prevention (CDC) said the mother was likely infected while in Brazil in May 2015. Voice of America News reported that the baby has suffered brain damage.
US health officials said there is no risk of transmission in Hawaii, where there has never been a case of a person acquiring Zika in the state. Six people have acquired the virus in other countries since 2014.
At least 26 Americans have been diagnosed with Zika since 2007, all of them travellers who are believed to have caught it overseas. In addition, a person in Puerto Rico who had not travelled was diagnosed with the illness last month.
What is the advice?
Last month, the CDC advised US travellers to take protect themselves against mosquito bites if they visit places in Latin America or the Caribbean where Zika has been spreading. The advice includes wearing long sleeves and long pants and using insect repellent.
On Friday night, the CDC came out with an alert asking pregnant women - at any stage of pregnancy - to postpone travel to 14 destinations in Latin America and the Caribbean.
In Brazil, most of the mothers who had babies with the condition, called microcephaly, were apparently infected during the first trimester, but there is some evidence the birth defect can occur later in the pregnancy, said the CDC’s Dr Cynthia Moore.
Another CDC official, Dr Lyle Petersen, said the virus seems to remain in the blood for only about a week or two.
The link between Zika and the birth defect was not noted earlier as previous outbreaks were much smaller, and the problem may have occurred less often and so was harder to recognise, he said.
There is another travel alert for pregnant women already in place, discouraging travel to areas where malaria is spreading.
THE Ministry of Health in the Bahamas is monitoring the spread of the Zika virus, which has been found in several Latin American and Caribbean countries, Minister of Health Dr Perry Gomez said yesterday.
Officials in the United States have advised pregnant women to avoid travelling to countries in the region that have outbreaks of a tropical illness linked to birth defects. The illness is caused by the Zika virus, which is spread through mosquito bites. It causes only a mild illness in most people but has been spreading around the world and into the Caribbean and there is mounting evidence linking it to a terrible birth defect, especially in Brazil.
US health officials have said pregnant women should consider postponing trips to 14 destinations - Brazil, Colombia, El Salvador, French Guiana, Guatemala, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Puerto Rico, Suriname and Venezuela, adding that women who are trying to get pregnant or thinking of getting pregnant should talk to their doctor before travelling to those areas, and to take extra precautions to avoid mosquito bites.
When contacted yesterday, Dr Gomez said the Ministry of Health has been tracking the spread of the virus for months. While the virus has not been seen in the Bahamas, he said he believes that the Department of Environmental Health has increased its fogging programme to limit mosquito populations.
Haiti’s Public Health Minister Florence Duperval Guillaume announced on Friday that there have been five confirmed cases of the Zika virus in Haiti. She says they are all in the area of Port-au-Prince, the overcrowded capital, where many people live in shacks with little protection from mosquitoes.
Zika is a Dengue-like virus that causes a mild illness in most people. The US Centers for Disease Control and Prevention (CDC) said last week that evidence of the virus was found in Brazil in the placentas from two women who miscarried and the brains of two newborns who died. Those who were born had small heads, a rare condition known as microcephaly. Brazil has been experiencing the largest known Zika outbreak and a surge of birth defects.
“The evidence is becoming very, very strong of the link between the two,” said Dr Lyle Petersen, director of mosquito-borne diseases at the CDC. Finding the virus present in brain tissue is “very significant”, he said. Dr Petersen warned that the link is not yet definite and said that a team of CDC investigators is travelling to Brazil in a few weeks to conduct more studies and learn what risks face pregnant women. “It’s possible that there may be some other co-factors involved,” he said.
Zika is spread by the same Aedes mosquito that can carry Dengue and Chikungunya. There are no known cases of people contracting the virus in the US mainland, though it has been seen in returning travellers. Puerto Rico reported its first case of Zika two weeks ago, and 13 countries in Latin America have also seen infections.
“I don’t think anybody has any idea how Zika is crossing the placenta into these fetuses, or why Zika is doing it and other closely related viruses like Dengue don’t,” said Scott Weaver, director of the Institute for Human Infections and Immunity at the University of Texas Medical Branch in Galveston.
Dr Ernesto Marques, an infectious diseases researcher at the University of Pittsburgh who is also studying Zika and the birth defects outbreak in Brazil, said he is finding so far that a very small percentage of pregnant women who reported Zika symptoms gave birth to babies with microcephaly. He said a problem facing epidemiologists is the lack of laboratories that are able to test for Zika. Dr Marques said estimates that the country had between 440,000 and 1.3 million cases of the virus in 2015 are not reliable. “It needs to be better diagnosed. We don’t know many, and we need a better response,” he said.
Brazilian health authorities have said there is no question Zika is behind the birth defects. The Health Ministry said last Tuesday that 3,530 babies have been born with microcephaly in the country since October. The number was less than 150 in 2014.
Now the government finds itself with a growing number of children with mental retardation concentrated in one of the poorest regions of the country in the northeast, though cases in Rio de Janeiro and other big cities have also been on the rise, prompting people to stock up on mosquito repellent.
Some women of means have left the country to spend their pregnancies in the United States or Europe to avoid infection.
On Wednesday, Alberto Beltrame, national secretary of health care, said the Brazilian government would invest $163 million to provide care and physical and speech therapy to those babies through the first three years.
On Friday, the government went a step further, announcing it will direct funds to a biomedical research centre to help develop a vaccine against the virus. Health Minister Marcelo Castro said that the goal is for the Sao Paulo-based Butantan Institute to develop “in record time” a vaccine for Zika. Institute director Jorge Kalil said that is expected take three to five years.
“Today there is only one way to fight the Zika virus, which is to destroy the mosquito’s breeding grounds,” Mr Castro said. “The final victory against the virus will only come when we develop a vaccine against that disease.”
In the United States, Connecticut’s Department of Public Health is asking health care providers across the state to report any suspected cases of Zika. The agency says there are currently no reported cases of the virus in Connecticut.
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