Nowadays, doctors in Canada are investigating a mysterious brain disease which is seen around New Brunswick’s bucolic Acadian peninsula. The health conditions of some of these patients in this region deteriorated rapidly with some symptoms varying from delusion, speech problems, hallucinations, aggression, involuntary movement of muscle, to progressive dementia.
Doctors thought the reason for the symptoms does mimic Creutzfeldt-Jakob disease (CJD) which is a very rare and but fatal disease. The first case was found in 2015. After that additional 11, 24, 6 cases are found in 2019, 2020, 2021, respectively. Patients’ ages are among 18-85 and six of them died from the disease.
Although the onset of symptoms is from 2018, it is evaluated that patients got the disease as early as 2013. There is no diagnosis for the disease so far. Investigations are focused on whether this condition is a new unknown variety of CJD. Moreover, investigations are going ahead on what the source of the disease in this area is.
Creutzfeldt-Jakob disease (CJD) is a rapidly progressive neurodegenerative disorder that is always fatal. CJD may lead to dementia and death within one year. It is believed that an abnormal variant of prion protein causes CJD. As a misfolded protein, the prion is the cause of the disease that can transmit between animals, also transmission may occur between humans via transplantation or transfusion.
Casual contact is not a transmission way for humans. Abnormal prion protein accumulation causes brain damage and CJD. Annual incidence is one case in every million population. There are different forms of CJD which are classic CJD, variant CJD (vCJD), fatal familial insomnia, Gerstmann-Sträussler-Scheinker syndrome, and kuru.
Classic CJD can be familial (15%) of cases or sporadic (85%) of cases . Beside people inheriting the familial CJD, sporadic cases start without any known cause at peak age at onset between 55 to 75years , with a median age of 68yrs.at age 60s. The disease quickly causes neurological problems and eventually most patients die in one year, with the mean survival from 4 to 6 months.
The familial or genetic type is usually due to autosomal dominant mutations in the PRNP gene encoding the prion protein. There is usually a positive family history and a positive genetic mutation test . Another type of CJD is variant CJD which is related to eating the meat of infected animals by mad cow disease. Variant CJD can infect young people.
Symptoms of CJD
Even though symptoms of CJD are similar to Alzheimer’s disease, rapid progress is typical for CJD with death in one year after the onset of symptoms. However, starting symptoms may take years. Therefore, CJD is mainly seen in elderly people.
Symptoms of CJD include;
-Dementia,
-Involuntary movements of muscle, myoclonus
-Loss of intellect and memory,
-Personality changes,
-Slurred speech
-Deterioration of brain function
-Balance problems,
-Incoordination
-Insomnia
Diagnosis
Variability of clinical presentation causes delays in diagnosis. In addition to clinical symptoms, electroencephalogram, blood tests, brain magnetic resonance imaging (MRI) can be used to diagnose CJD. Autopsy and pathological evaluation of tissue is the gold standard, but there are some concerns about precautions in autopsy due to being transmissible disease.
How CJD is Transmitted
It is not possible to spread disease by airborne or sexual contact between humans, but it is possible via blood transfusion and transplantation of affected tissue.
There are three different ways to develop CJD;
-Sporadically
-Inheritance
-Iatrogenic /Contamination
Most cases present with no reason are called sporadically. Less than 15% of cases have a genetic mutation or a family history is called inheritance transmission. Contamination is rare to be transmitted by infected human tissue or consuming meat from infected with mad cow disease. Transmission can be via skin and cornea transplant or contaminated surgical instruments.
Prevention:
Since most cases are sporadic, there are no prevention methods for these cases. On the other hand, because of the long incubation period, diagnosis and taking action to prevent contamination of disease are usually delayed. Risk factors are family history of CJD, consuming the meat of infected animals by mad cow disease, and undergoing transplant or transfusion from an infected human. Most of these risk factors are not preventable.
How CJD is Treated:
Unfortunately, there is currently no treatment of CJD except alleviating the symptoms and making patients as comfortable as possible for which painkillers and antidepressants can be used. Despite the treatment, CJD is always fatal within one year after symptoms start.