text: “It’s pretty obvious that in all seven sites there is a clear relationship,” said Dr. Marcos A. Espinal, the study’s lead author and the director of communicable diseases at the Pan American Health Organization, which collected data on confirmed and suspected cases of Zika infection and on the incidence of Guillain-Barré. “Something is going on.” 
   
   In Venezuela, officials expected roughly 70 cases of Guillain-Barré from December 2015 to the end of March 2016, as mosquitoes were spreading the virus. Instead, there were 684 cases. 
   
   Similarly, during five months in which the Zika virus was circulating in Colombia, officials recorded 320 cases of Guillain-Barré when there should have been about 100. From September 2015 to March 2016, while Zika infections peaked in El Salvador, cases of Guillain-Barré doubled to 184 from 92. 
   
   The researchers included patients with both suspected and confirmed Zika infections, as reported by national health officials. 
   
   Newsletter Sign Up Continue reading the main story Please verify you're not a robot by clicking the box. Invalid email address. Please re-enter. You must select a newsletter to subscribe to. Sign Up You agree to receive occasional updates and special offers for The New York Times's products and services. Thank you for subscribing. An error has occurred. Please try again later. View all New York Times newsletters. 
   
   Dr. Kenneth C. Gorson, professor of neurology at Tufts University School of Medicine, who was not involved with the new analysis, called it compelling. 
   
   “This is a substantial public health burden for countries that may not have well-developed health systems in place,” he said. “They have to have enough ventilators and I.C.U. beds.” About one-third of patients with Guillain-Barré require breathing assistance, he said. 
   
   Over all, Dr. Espinal and his authors found increases in Guillain-Barré that were two to 10 times what would normally be expected. Roughly 500 million people in Latin America and the Caribbean are at risk for Zika virus infection, so even modest increases in the incidence of Guillain-Barré are worrisome. 
   
   The nations in the study included the Dominican Republic, El Salvador, Honduras, Suriname, Venezuela and Colombia, along with the state of Bahia in Brazil. (National data from Brazil was not available until February 2016.) 
   
   Advertisement Continue reading the main story 
   
   Collectively, they reported a total of nearly 1,500 cases of temporary paralysis. The reported incidence was 28 percent higher for men and increased with age for both sexes, in line with previous research. 
   
   Temporary paralysis is a potential neurological complication of dengue infection, too. But Dr. Espinal and his colleagues looked for a similar link to dengue and found none. 
   
   Dr. Gorson noted that the continental United States has no formal monitoring system for Guillain-Barré. As the number of Zika cases in Florida and elsewhere increases, he said, “you won’t know if a Guillain-Barré case is related to Zika infection.” 
   
   “We can do it,” he said of such surveillance. But “there’s no funding from Congress to do it.” ||||| SAN JUAN, Puerto Rico (AP) — Puerto Rico on Friday reported its first death from a paralysis condition that developed from a Zika infection as the U.S. territory fights an epidemic of the mosquito-borne virus. 
   
   The victim was a man between 35 and 45 years old from the San Juan metro area who died from Guillain-Barre, according to state epidemiologist Brenda Rivera. The condition can cause temporary paralysis and in rare instances, death. 
   
   Rivera noted that it's unusual for the victim to be so young. 
   
   "What does this tell us? That all of us are susceptible," Rivera said as she urged Puerto Ricans to protect themselves from the mosquito-borne virus. 
   
   The man, who died last month, was obese but did not have any other health conditions, she said. No further details about the victim were provided. 
   
   The U.S. territory has a total of 13,186 confirmed Zika cases, with a total of 102 hospitalizations and 34 cases of Guillain-Barre. The number of Zika cases is believed to be much higher because eight of 10 people have no symptoms and many do not go to the doctor. Those infected include 1,106 pregnant women, which is a concern because Zika has been linked to severe birth defects. 
   
   "We are not going to see the effects of Zika today," Rivera said. "We are going to see them in the next couple of months, in the next several years." 
   
   Puerto Rico reported the first Zika-related microcephaly case acquired on U.S. soil in May, involving a dead fetus that a woman turned over to health authorities. Since then no microcephaly cases have been reported, but federal officials say it is only a matter of time. A study published Friday in JAMA Pediatrics estimates that up to 10,300 pregnant women in Puerto Rico could be infected with Zika and that between 100 to 270 babies could be born with microcephaly through mid-2017. 
   
   In addition, some babies infected with Zika may present other type of problems such as eye abnormalities, hearing loss and inflexible joints, said Dr. Peggy Honein, chief of the birth defects branch at the U.S. Centers for Disease Control and Prevention. 
   
   "We are very concerned about these often devastating outcomes," she said in a phone interview. 
   
   Honein, who was involved in the study, said that one of the major challenges of the Zika outbreak is the time delay in babies being born with severe defects. 
   
   "It doesn't mean that it's not happening because we don't see the effects yet," she warned. 
   
   The U.S. government last week declared a public health emergency in Puerto Rico because of Zika, and federal officials have warned that up to 25 percent of Puerto Rico's nearly 3.5 million people could become infected. 
   
   The CDC recently urged Puerto Rico fight Zika with the insecticide naled through aerial spraying, but the governor rejected that proposal and instead authorized the use of Bti, an organic larvicide. ||||| Our apologies. An error occurred while setting your user cookie. Please set your browser to accept cookies to continue. 
   
   NEJM.org uses cookies to improve performance by remembering your session ID when you navigate from page to page. This cookie stores just a session ID; no other information is captured. Accepting the NEJM cookie is necessary to use the website. 
   
   1-800-843-6356 | [email protected] ||||| There’s more evidence that Zika virus infection can cause a paralyzing side effect called Guillain-Barré syndrome. 
   
   Instances of Guillain-Barré skyrocketed in countries hit by Zika virus epidemics — by as much as 877 percent in Venezuela, health officials and researchers from Latin America reported. At the very least, rates doubled, the officials said in a letter to the New England Journal of Medicine. 
   
   A specialist at Harris County Public Health and Environmental Services holds a box that contains captured mosquitoes. Jennifer Weiss / NBC News 
   
   “During the weeks of Zika virus transmission, there were significant increases in the incidence of the Guillain–Barré syndrome, as compared with the pre-Zika virus baseline incidence, in (Brazil’s) Bahia State (an increase of 172 percent), Colombia (211 percent), the Dominican Republic (150 percent), El Salvador (100 percent), Honduras (144 percent), Suriname (400 percent), and Venezuela (877 percent),” they wrote. “When the incidence of Zika virus disease increased, so did the incidence of the Guillain–Barré syndrome.” 
   
   Doctors are fairly certain that Zika can cause Guillain-Barré syndrome, a little understood reaction in which the immune system attacks the nerves. It can cause temporary but often severe paralysis. In extreme cases, patients must be put on ventilators to help them breathe until they recover. 
   
   Related: Rare Zika Complication Hits 30 in Puerto Rico 
   
   It can be fatal — Guillain-Barré caused by Zika killed a man in Puerto Rico last month. It's usually seen in about every 5,000 to 10,000 infections like Zika. Other infections also can cause Guillain-Barré. 
   
   “When the incidence of Zika virus disease increased, so did the incidence of the Guillain–Barré syndrome.” 
   
   Zika’s worst effect is the brain and nerve damage it causes in developing fetuses. It can devastate the growing brain and there is no way to prevent or reverse the effects. 
   
   Pregnant women in Zika-affected zones are warned to avoid mosquito bites if they possibly can by using repellents, covering up with clothing and staying inside behind screens and air conditioning. But these facilities are often not available in some of the worst-hit places. 
   
   The researchers found more women than men reported Zika infections, but said that might be because women are more aware of the risks because of the pregnancy link. However, men were more likely to develop Guillain-Barré. 
   
   “From April 1, 2015, to March 31, 2016, a total of 164,237 confirmed and suspected cases of Zika virus disease and 1,474 cases of the Guillain–Barré syndrome were reported in Bahia, Brazil; Colombia; the Dominican Republic; El Salvador; Honduras; Suriname; and Venezuela,” they wrote. “The reported incidence of the Guillain–Barré syndrome was 28 percent higher among males than among females and consistently increased with age, findings that are in line with previous reports.” 
   
   “The reported incidence of the Guillain–Barré syndrome was 28 percent higher among males than among females.” 
   
   Zika has often circulated quietly, in part because it doesn’t cause symptoms in most people and in part because it looks like so many other mosquito-borne diseases, such as dengue virus. 
   
   The health officials suggested that watching for Guillain-Barré cases might be one way to spot Zika outbreaks. 
   
   Related: Zika Link to Birth Defects, Guillain-Barré 'Alarming' 
   
   “Approximately 500 million people in Latin America and the Caribbean are at risk for Zika virus infection,” they wrote. 
   
   “It is clear that increases in the incidence of the Guillain–Barré syndrome to a level that is 2 and 9.8 times as high as baseline, as we have reported here, impose a substantial burden on populations and health services in this region.” ||||| Guillain-Barré syndrome (GBS) is an uncommon sickness of the nervous system in which a person’s own immune system damages the nerve cells, causing muscle weakness, and sometimes, paralysis. Several countries that have experienced Zika outbreaks recently have reported increases in people who have Guillain-Barré syndrome (GBS). 
   
   Current CDC research suggests that GBS is strongly associated with Zika; however, only a small proportion of people with recent Zika virus infection get GBS. CDC is continuing to investigate the link between GBS and Zika to learn more. 
   
   Symptoms of GBS 
   
   GBS symptoms include weakness of the arms and legs and, in severe cases, can affect the muscles that control breathing. 
   
   These symptoms can last a few weeks or several months. Most people fully recover from GBS, though some people have permanent damage. Very few people die from GBS. 
   
   Causes of GBS 
   
   Researchers do not fully understand what causes GBS. Most people with GBS report an infection before they have GBS symptoms. Rarely, vaccination has also been associated with the onset of GBS (for example, the 1976 Swine influenza vaccine). 
   
   GBS is rare 
   
   An estimated 3,000 to 6,000 people, or 1-2 cases for every 100,000 people, develop GBS each year in the US. Most cases of GBS tend to occur for no known reason, and true “clusters” of cases of GBS are very unusual. 
   
   What to do if you are concerned 
   
   If you want to know more about the number of GBS cases in a certain area, contact the state or local health department in the state where the cases happen. CDC collaborates with state and local health departments to investigate reports of possibly unusually large numbers or “clusters” of GBS cases. 
   
   Additional Resources 
   
   Vaccine Safety Concerns- Guillain-Barré Syndrome 
   
   Guillain-Barré syndrome and Flu Vaccine: Questions and Answers
target: – Earlier this month, Puerto Rico announced its first death from Guillain-Barre syndrome, a condition causing temporary paralysis that, in this case, was linked to the Zika virus. Now incidences of Guillain-Barre are said to have risen in seven countries in tandem with outbreaks of Zika, per a study in the New England Journal of Medicine. The New York Times notes that while the CDC remains wary of saying Zika can cause GBS (it simply says GBS is "strongly associated" with Zika), this research offers further evidence that Zika may indeed be responsible—worrisome news, as about 500 million people in Latin America and the Caribbean are vulnerable to becoming infected with it. "It's pretty obvious that in all seven sites there is a clear relationship," says lead author Dr. Marcos A. Espinal of the Pan American Health Organization. The study found nearly 165,000 cases of Zika virus (some confirmed, some suspected) between April 2015 and March 2016, as well as almost 1,500 cases of GBS, reported in the Brazilian state of Bahia, Colombia, the Dominican Republic, El Salvador, Honduras, Suriname, and Venezuela. During the weeks of Zika outbreaks in these areas, the incidence of GBS cases spiked compared to pre-Zika baseline numbers—jumping as much as 877% in Venezuela. Women had a 75% higher reported incidence rate of Zika than men, but men had a GBS incidence rate 28% higher than women's, and incidence rates also climbed with age, NBC News reports. (The CDC's Zika funds are almost gone.)