zika

Zika mystery deepens with evidence of nerve cell infections

Top Zika investigators now believe that the birth defect microcephaly and the paralyzing Guillain-Barre syndrome may be just the most obvious maladies caused by the mosquito-borne virus.

Fueling that suspicion are recent discoveries of serious brain and spinal cord infections – including encephalitis, meningitis and myelitis – in people exposed to Zika.

Evidence that Zika’s damage may be more varied and widespread than initially believed adds pressure on affected countries to control mosquitoes and prepare to provide intensive – and, in some cases, lifelong – care to more patients. The newly suspected disorders can cause paralysis and permanent disability – a clinical outlook that adds urgency to vaccine development efforts.

[divider style=”solid” top=”20″ bottom=”20″]
WHO sees scientific consensus on Zika
[divider style=”solid” top=”20″ bottom=”20″]

Scientists are of two minds about why these new maladies have come into view. The first is that, as the virus is spreading through such large populations, it is revealing aspects of Zika that went unnoticed in earlier outbreaks in remote and sparsely populated areas. The second is that the newly detected disorders are more evidence that the virus has evolved.

“What we’re seeing are the consequences of this virus turning from the African strain to a pandemic strain,” said Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine.

The Zika outbreak was first detected in Brazil last year and is spreading through the Americas. It has been linked to thousands of suspected cases of microcephaly, a typically rare birth defect marked by unusually small head size, signaling a problem with brain development. Evidence linking Zika to microcephaly prompted the World Health Organization to declare a global health emergency in February.

The suspicion that Zika acts directly on nerve cells began with autopsies on aborted and stillborn fetuses showing the virus replicating in brain tissues. In addition to microcephaly, researchers reported finding other abnormalities linked with Zika including fetal deaths, placental insufficiency, fetal growth retardation and injury to the central nervous system.

Doctors also are worried that Zika exposure in utero may have hidden effects, such as behavioral problems or learning disabilities, that are not apparent at birth.

[divider style=”solid” top=”20″ bottom=”20″]
Puerto Vallarta combating Zika
[divider style=”solid” top=”20″ bottom=”20″]

“If you have a virus that is toxic enough to produce microcephaly in someone, you could be sure that it will produce a whole series of conditions that we haven’t even begun to understand,” said Dr. Alberto de la Vega, an obstetrician at San Juan’s University Hospital in Puerto Rico.

First discovered in the Zika forest of Uganda in 1947, the virus circulated quietly in Africa and Asia, causing rare infections and producing mild symptoms. A 2013 outbreak in French Polynesia, the largest at that time, led researchers to make the Guillain-Barre link. Other neurological effects were noted but scientists made little of them at the time.

A rare and poorly understood condition, Guillain-Barre can weaken muscles and cause temporary paralysis, often requiring patients to need respirators to breathe.

An estimated 32,000 people in the French Polynesia Zika outbreak were infected, and 42 patients were confirmed to have Guillain-Barre, a 20-fold increase in incidence over the previous four years, the WHO reported. Another 32 patients had other neurological disorders, including encephalitis, meningoencephalitis, myelitis and facial paralysis.

Guillain-Barre is an autoimmune disorder, in which the body attacks itself in the aftermath of an infection. But the newly discovered brain and spinal cord infections are known to be caused by a different mechanism – a direct attack on nerve cells. That has prompted scientists to consider whether the Zika virus also may infect nerves directly in adults, as they already have suspected in fetuses.

[divider style=”solid” top=”20″ bottom=”20″]
Mexico confirms 11 cases of Zika in pregnant women
[divider style=”solid” top=”20″ bottom=”20″]

In medical journals published last month, doctors described neurological syndromes in two patients that they attributed to Zika. Doctors in Paris diagnosed meningoencephalitis, an infection of both the brain and spinal cord, in an 81-year-old man who was hospitalized after being exposed to Zika on a cruise.

Another French team reported acute myelitis, a paralyzing infection of the spinal cord, in a 15-year-old girl who had been infected with Zika on the French Caribbean island of Guadeloupe.

In its latest surveillance report, the WHO said the two cases “highlight the need to better understand the range of neurological disorders associated with Zika-virus infection.”

Other mosquito-borne viruses – including dengue, Japanese encephalitis and West Nile – are known to directly infect nerve cells in the brain and spinal cord. But such viruses are seldom associated with Guillain-Barre, and never with microcephaly, said Baylor’s Hotez.

POSSIBLE EVOLUTION

In a recent paper, WHO researcher Mary Kay Kindhauser wrote that Zika “appears to have changed in character,” noting its transition from a mild infection to one causing “large outbreaks linked with neurological disorders.”

Scientists studying Zika in Brazil now are reporting the same neurological disorders seen in French Polynesia. From April through July 2015, doctors in Brazil identified a spike in Guillain-Barre cases.

In Salvador, there were roughly 50 reported cases of Guillain-Barre in July alone, far more than would typically be expected, Dr. Albert Ko, a tropical disease expert from Yale University who is studying Zika in the coastal city of Salvador, recently told a research symposium.

[divider style=”solid” top=”20″ bottom=”20″]
Mexico says tourist not at risk for Zika
[divider style=”solid” top=”20″ bottom=”20″]

“Throughout Brazil, doctors have seen strange, atypical, neurological manifestations,” Ko said told the symposium.

Zika exposed patients have had other neurological problems as well, including acute disseminated encephalomyelitis, which causes inflammation of the myelin, the protective sheath covering nerve fibers in the brain and spinal cord. Other patients experienced tingling, prickling or burning sensations, which are often markers of peripheral nerve damage.

In addition to Brazil and French Polynesia, at least 11 more countries and territories have reported hundreds of cases of Guillain-Barre syndrome linked to Zika. In Brazil, Guillain-Barre cases jumped 19 percent to 1,708 last year.

El Salvador, a country that has an annual average of 196 cases of Guillain-Barre, reported 118 cases in six weeks in December and January.

Zika’s arrival in Colombia in October 2015 was associated with another increase in Guillain-Barre cases. The country typically reports 242 cases of the syndrome a year, or about five a week. But in the five weeks starting in mid-December, Colombia reported 86 cases of Guillain-Barre, or about 17 a week.

Dr. Carlos Pardo-Villamizar, a neurologist at Johns Hopkins University School of Medicine, is studying Zika complications with colleagues in five Colombian research centers. They have seen cases of encephalitis, myelitis and facial paralysis associated with Zika and want to understand what is triggering these complications.

They also want to study whether prior infection with dengue or chikungunya – two related viruses – are contributing to neurological disorders seen in patients with Zika.

Scientists are turning their attention next to Puerto Rico, where Zika is expected to infect hundreds of thousands of residents by year-end.

More cases hold the potential for “a better sense of the full spectrum of disease that Zika is capable of causing,” said Dr. Amesh Adalja of the Center for Health Security at the University of Pittsburgh Medical Center.

(Reporting by Julie Steenhuysen; additional reporting by Anthony Boadle in Brasilia, Brazil; Editing by Michele Gershberg and Lisa Girion)

Top Zika investigators now believe that the birth defect microcephaly and the paralyzing Guillain-Barre syndrome may be just the most obvious maladies caused by . . .

Follow Us On Google News | Get Our Newsletter



Trending News on PVDN

  • tropical-storm-erick-hurricane-watch-southern-mexicoTropical Storm Erick Strengthening as Hurricane Watch Issued for Southern Mexico Tropical Storm Erick is forecast to become a hurricane before making landfall in southern Mexico. A Hurricane Watch is now in effect from Bahias de Huatulco to Punta Maldonado. Tropical Storm Erick continues to gather strength off Mexico’s southern Pacific coast and is forecast to become a hurricane by Wednesday, according to the latest advisory…
  • huracan-erick-2025-mexico-peligroHurricane Erick Becomes Eastern Pacific’s Strongest Cyclone of 2025, Eyes Mexico’s Southwest Coast Hurricane Erick rapidly intensified off Mexico’s Pacific coast, becoming the second hurricane of the 2025 season and threatening southwestern Mexico with dangerous wind, rain, and storm surge. This story is available in Spanish: El huracán Erick se fortalece rápidamente y amenaza la costa suroeste de México The 2025 eastern Pacific hurricane season continues to surge…
  • tropical-storm-erick-warnings-mexico-coastHurricane Erick will bring heavy rains to Puerto Vallarta Hurricane Erick Puerto Vallarta will bring heavy rains to Puerto Vallarta by Friday but poses no risk to the northern coast of Jalisco. Meteorologist Víctor Manuel Cornejo López, of the Civil Protection scientific committee for the Bay, reports that Hurricane Erick will deliver significant rainfall to Puerto Vallarta without threatening the region’s safety. According to…
  • tropical-storm-erick-oaxaca-hurricane-warningTropical Storm Erick Threatens Oaxaca as Mexico Activates Civil Protection Plan Mexico activates a civil protection plan as Tropical Storm Erick strengthens. The storm may become a Category 2 hurricane, putting 22 municipalities in Oaxaca at risk. The Government of Mexico has activated its civil protection plan as Tropical Storm Erick moves closer to the country's southern Pacific coast, with Oaxaca, Chiapas, and Guerrero under direct…
  • Know your consumer rights in Mexico Is it legal for restaurants to include the tipPuerto Vallarta restaurants face 33 percent staff shortage Restaurants in Puerto Vallarta face a 33% staffing shortfall as they prepare for a busy summer holiday season, aiming to boost sales by up to 60% despite ongoing labor challenges. As Puerto Vallarta prepares to welcome a surge of summer tourists, the city’s restaurant sector is grappling with a serious staffing problem—operating with roughly one-third…
  • puerto-vallarta-flooding-first-storm-2025Puerto Vallarta hit by flooding, fallen trees, and damaged roads after first storm of the season Heavy rain and a nighttime storm caused widespread flooding, road closures, and downed trees in Puerto Vallarta. Several key roads remain impassable. PUERTO VALLARTA — The first major storm of the rainy season swept through Puerto Vallarta overnight, leaving behind extensive damage across the city, including widespread flooding, blocked roads, and fallen trees. By morning,…
  • tropical-cyclone-mexico-pacific-june-2025New Tropical Cyclone Likely to Form Off Mexico’s Pacific Coast This Week Meteorologists warn of a 90% chance a new tropical cyclone will form midweek off Mexico’s Pacific coast, as Dalila weakens and rains persist across southern Mexico. As Tropical Storm Dalila moves farther out to sea and becomes post-tropical, meteorologists are turning their attention to a new disturbance brewing off Mexico’s Pacific coast, which is highly…
  • american-woman-drowns-santa-maria-los-cabosAmerican Woman Drowns at Closed Beach in Los Cabos Despite Black Flag Warning A 57-year-old American woman drowned at Santa María Beach in Los Cabos, Baja California Sur, on June 17, despite black flag warnings indicating the beach was closed due to dangerous conditions. Los Cabos, Baja California Sur – Tragedy struck the beaches of Los Cabos on the afternoon of June 17, when a 57-year-old American woman…
  • Queretaro rainsRain washes away 71 homes in Querétaro and El Marqués Rains from Tropical Storm Dalila caused flooding and landslides that damaged 71 homes in Querétaro and El Marqués. A 30 million peso contingency fund has been activated. Tropical Storm Dalila left a trail of destruction across the metropolitan region of Querétaro, with heavy rains causing flooding and landslides that affected at least 71 homes in…
  • sargassum-slams-cancun-playa-restaurantsSargassum Crisis in Cancún and Playa del Carmen Forces Restaurants and Beach Clubs to Cut Staff Businesses in Cancún and Playa del Carmen report steep losses due to sargassum, with restaurants losing diners and beach clubs sending staff on unpaid leave. Restaurants and beach clubs along the shores of Puerto Juárez in Cancún and Playa del Carmen are grappling with a sharp downturn in business due to a relentless invasion of…
Scroll to Top