Tag Archives: encephalitis

Extremely rare case of death from bat rabies in France

Most bats do not have rabies. According to the US Centers for Disease Control and Prevention (CDC), even among bats submitted for rabies testing, only about 6% had rabies. Rabies can only be confirmed in a laboratory but any bat that is active by day or is found in a place where bats are not usually seen like in your home or on your lawn or attic could be rabid. A bat that is weak and unable to fly could potentially be sick.

A man died of rabies in Limoges, in southwest central France, most probably after being bitten or scratched by a bat, as reported recently by the Institut Pasteur. This is a first in mainland France.  The sixty-year-old succumbed to encephalitis, an inflammation of the brain of unexplained origin, in August 2019. A partnership established between the Necker hospital and the Pasteur Institute, aimed at identifying the causes of undocumented encephalitis, led to the genetic analysis of post-mortem samples. These analyzes at Necker Hospital in Paris showed that he had contracted a lyssavirus, European Bat LyssaVirus type 1 (EBLV-1), sheltered by bats.

“This shows that there are cases of rabies that we can miss”

“It is thanks to this retrospective diagnosis that this case was brought to light. This shows that there are cases of rabies that can be missed, ” explained Laurent Dacheux, deputy head of the national reference center for rabies at the Institut Pasteur.

“The trace of this virus was identified at that time, in November 2020. In the midst of the coronavirus , and this discovery went unnoticed”, continues Laurent Dacheux. This exceptional case was finally mentioned in a popular science article on the Mesvaccins.net site and highlighted by the regional daily Le Populaire du Center .

In contact with bats

“It has been thirty-five years since a death of this type has occurred in the world. And in mainland France, this is indeed a first,” assures Laurent Dacheux.

In 2019, a 21-year-old man died of rabies after coming into contact with a bat on Vancouver Island in the Canadian province of British Columbia. Health official Bonnie Henry confirmed that the man came into contact with a rabid bat in mid-May, began showing symptoms six weeks later, and died in July 2019.

Why don’t people get the rabies vaccine? 

Rabies is a fatal disease. Each year, tens of thousands of people are successfully protected from developing rabies through vaccination after being bitten by an animal like a bat that may have rabies.

In some cases, people who died of rabies knew they were bitten by a bat. They did not go to a doctor to seek medical help because they were not aware that bats can have rabies and transmit it through a bite. In other cases, it is also possible that young children may not fully awaken due to the presence of a bat (or bite) or may not report a bite to their parents. Most bats have small teeth which may leave marks that can disappear quickly.

Which animals can be infected with rabies? 

Any mammal can contract rabies. Rabies is most often reported in mammals that tend to come in contact with humans or live near human settlements, including bats, raccoons, skunks, and foxes. Cases of rabies have also been reported in deers, woodchucks, mongoose, opossums, coyotes, wolves, and monkeys. Pets and domesticated animals that are mammals can easily get the disease if bitten by another animal that is already infected. Cases in pets and other domesticated animals have been reported in dogs, cats, cows, horses, and rabbits.

If you are bitten by an animal – or if infectious material (such as saliva) from an animal gets into your eyes, nose, mouth, or a wound – it is important to wash the affected area thoroughly with soap and water and get medical advice immediately. Whenever possible, the animal should be captured and sent to a laboratory for rabies testing.

Shrew-transmitted Borna virus linked to killer brain infections

Rubbenstroth D, Schlottau K, Schwemmle M, Rissland J, Beer M (2019) Human bornavirus research: Back on track! PLoS Pathog 15(8): e1007873.

In a recent Lancet Infectious Diseases publication, researchers describe eight human fatalities in Germany caused by Borna disease virus 1 (BoDV-1) and suggest that wider testing for the disease may be useful in regions where the virus occurs in the wild.

The study was based on data collected from the brain tissue of 56 patients who died of an unidentified virus and presented with encephalitis (inflammation of the brain). Six of those patients had BoDV-1, and two were likely infected. The newly confirmed cases raise the number of published BoDV-1 deaths in the endemic area to 14.

All patients in which the virus has been newly diagnosed died between 1999 and 2019, and they all lived in southern Germany. However, the authors cannot rule out that it could be behind milder cases of encephalitis, especially in regions of central Europe where the infected host animal species occur in the wild. It was thought it might play a role in psychiatric disorders, such as depression or schizophrenia, but until the virus was reported in four cases in 2018, its links to unexplained encephalitis were rarely investigated.

Originally identified in sheep and horses in Europe, BoDV has since been found to occur in a wide range of warm-blooded animals including birds, cattle, cats, and primates and has been found in animals in Europe, Asia, Africa, and North America. The virus name is derived from the town of Borna in Saxony, Germany, which suffered an epidemic of the disease in horses in 1885.

Credit: Pixabay.

BoDV-1-infected bicolored white-toothed shrews can be found in Germany, Austria, Switzerland, and Liechtenstein, but how the disease virus jumps from shrews to humans is not yet understood. Symptoms in infected people start with a fever, headache, and confusion, and continue with signs of brain disease such as an unsteady gait, memory loss, seizures, and a progressive loss of consciousness. In the new cases, symptoms deteriorated rapidly following patients’ admission to hospital, leading to deep coma and death. All eight patients died within 16 to 57 days of admission.

“Our findings indicate that Borna disease virus infection has to be considered a severe and potentially lethal human disease transmitted from a wildlife reservoir. However, it’s not a newly-emerging disease, but one that appears to have occurred unnoticed in humans for at least decades, and may have caused other unexplained cases of encephalitis in regions where the virus is endemic in the host shrew populations,” says Professor Barbara Schmidt from Regensburg University Hospital, Germany.

Writing in an accompanying commentary, Tomoyuki Honda, Ph.D. from Osaka University, Japan, said the study “has several implications for the pathology and epidemiology of bornavirus infection. It is time to relaunch human bornavirus research based on a theoretical framework that integrates the knowledge from these confirmed human bornavirus cases.”

Potentially fatal tick-borne brain disease found in the UK for first time

Tick-borne encephalitis virus (TBEV) has been found in the UK for the first time. The virus has been discovered as part of ongoing research by Public Health England and the Emerging and Zoonotic Infections National Institute for Health Research (NIHR) Health Protection Research Unit at the University of Liverpool.

Experts described the risk of infection as “very low,” but called on members of the public to be aware of ticks, small parasitic arachnids that are related to spiders and mites.

Front. Immunol., 26 September 2018 | https://doi.org/10.3389/fimmu.2018.02174

Tick-borne encephalitis (TBE) virus is an infection that causes no symptoms in most people. However, within one or two weeks of being bitten, some may complain of flu-like symptoms such as headaches, fever, fatigue and joint pain. In approximately one in ten cases, encephalitis or meningitis may follow, leading to severe headaches, light sensitivity, and dizziness, as well as problems with concentration, speech and walking. In rare cases, the virus can cause paralysis in the arms and legs and even death.

The infection is endemic in Scandinavia, mainland Europe, and parts of China and Japan. Ticks live in forests and grassy areas. It has now been detected in Thetford Forest, in eastern England, and the border between the southern counties of Hampshire and Dorset.

Earlier this year a European visitor became ill after being bitten by a tick in the New Forest area. This is a highly probable case of TBE. The patient, who was reported to PHE through the European Early Warning and Response System has since made a full recovery. No further cases in the UK have been identified. In 2017, there were 3,079 reported cases of TBE in Europe, including 9 associated fatalities.

https://www.youtube.com/watch?v=RhWlHsQnncw

The number of infections is increasing in Europe due to climate change and an increase in outdoor leisure pursuits, according to PHE. It is also possible that migratory birds introduced TBE-infected ticks to the UK, or they could have arrived along with pets traveling from endemic countries in Europe to the UK, according to PHE.

“Ticks carry a number of infections including Lyme disease, so we are reminding people to be ‘tick aware’ and take tick precautions, particularly when visiting or working in areas with long grass such as woodlands, moorlands and parks,” said Nick Phin of PHE.

Ticks are most active from May to October, although in some parts of Europe tick season could start as early as February if temperatures rise above 8 degrees Celsius. 

Experts recommend a TBE vaccine if you’re visiting a country where the infection is common and you’re planning to do outdoor activities when you get there. Two injections of the vaccine can protect you for about a year. A third injection can protect you for about 3 years. The first injection should be given at least 1 month before traveling.

Lyme disease remains a far more prevalent tick-borne health risk and health officials recommend that hikers walk on clearly defined paths and avoid brushing against vegetation where ticks may be present. Avoiding deep vegetation and sticking to paths will reduce the risk of tick bites, as will covering your skin and using insect repellants.

In 2018, a US congressional advisory committee said tick-related illnesses had become “a serious and growing threat to public health” and in July the US House of Representatives ordered an investigation into whether the Department of Defense had experimented with ticks and other insects as biological weapons.

Along came Alongshan virus, a new tick-borne disease

Blacklegged Tick.

This is what a blacklegged (deer) tick looks like.
Image credits Fairfax County / Flickr.

Tick-borne diseases, which afflict humans and other animals, are caused by infectious agents (viruses, bacteria, protozoa) transmitted by tick bites. As of 2016, 16 tick-borne diseases of humans have been identified, including Lyme diseasetularemiababesiosis and Rocky Mountain Spotted fever.

A group of patients in Inner Mongolia likely represent the first identified human cases of a new tick-borne illness — the Alongshan virus (ALSV). A description of ALSV, along with associated cases, was recently published in the New England Journal of Medicine. ALSV belongs to the jingmenvirus group in the flavivirus family. The first member of the group was described in 2014 and named the Jingmen tick virus (JMTV) because it was isolated from a tick in Jingmen, China.

In 2017, a 42-year-old woman (the index patient) presented to an Inner Mongolian hospital with a headache, fever, and history of tick bite. The woman showed signs of tick-borne encephalitis virus or TBEV but according to the study’s authors, “neither TBEV RNA nor antibodies against TBEV were detected.”

A total of 86 patients were eventually identified with similar symptoms. The patients were infected with an unknown segmented RNA virus, which the authors named ALSV. There were no deaths and all patients recovered with supportive care and the administration of antimicrobials and antivirals. However, 30 out of 86 (35%) patients experienced coma, which suggests ALSV can cause severe illness.

“Our findings suggest that ALSV may be the cause of a previously unknown febrile disease, and more studies should be conducted to determine the geographic distribution of this disease outside its current areas of identification,” the authors concluded. The authors noted the disease has only been found in Inner Mongolia an autonomous region of northern China and carried by Ixodes persulcatus ticks. Mosquitoes in the area, too, also purportedly carry the disease. It is not currently clear if patients are getting the illness exclusively from ticks or from mosquitoes.

New technologies such as next-generation sequencing have greatly accelerated the pace of discovery of new viruses in a wide range of hosts. In a related commentary, experts from the University of Texas Medical Branch at Galveston wrote, “The nature of ALSV, a unique virus in the family Flaviviridae with a vector that has a wide distribution, should warn us of its potential.”

ALSV is only one of the emerging pathogens that has recently been identified in China, in addition to Huaiyangshan banyangvirus (formerly SFTS virus) and Anaplasma capra. There will be more. The experts noted that a far more cost-effective way to understand the emergence of diseases and mitigate their outbreak is a proactive, real-time surveillance of human populations.

In summer months when tick season is at its height, it is recommended to check for ticks daily, especially under the arms, in and around the ears, inside the belly button, behind the knees, between the legs, around the waist, and on the hairline and scalp and shower soon after being outdoors.