The Oswaldo Cruz Foundation (Fiocruz) reported this Thursday (11) that it analyzes two suspected cases of Creutzfeldt-Jakob Disease (CJD). At first, Fiocruz had informed that they were suspected of Bovine Spongiform Encephalopathy, popularly known as mad cow disease. However, considering clinical and radiological aspects, the foundation explained, in a second statement, that suspicions are focused on CJD.
In a statement, the Ministry of Agriculture, Livestock and Supply (Mapa) clarified that the disease occurs, in most cases, sporadically and has an unknown infectious cause and source. “Thus, the suspected cases are not related to the consumption of beef or by-products contaminated with Bovine Spongiform Encephalitis (BSE), known as the ‘Mad Cow disease’”, says the statement from the ministry.
know what is Creutzfeldt-Jakob Disease, what are the symptoms, the possible causes and how the disease develops.
What is Creutzfeldt-Jakob disease?
A Creutzfeldt-Jakob disease, a fatal neurodegenerative disease that affects the central nervous system, caused by infectious agents called prions. Patients may have reasoning disorders, memory loss, speech impairment, lack of coordination of muscle movements and tremors.
Prions are particles made up of proteins found in cells of the nervous system of humans and other mammals. Under normal conditions, the cellular prion protein (PrPc) does not harm the body. It has several physiological functions, such as protecting neurons against cell death.
However, for reasons that are not fully understood, these proteins can show errors during their formation. These errors lead to changes in the protein’s structure, which becomes infectious and toxic.
“Under disease conditions, the protein starts to form aggregates that are infectious. They can then jump from one neuron to another, causing them to die. When the neuron dies, there is a loss of brain mass”, explained Sérgio Ferreira, a professor at the Institutes of Biochemistry and Biophysics at the Federal University of Rio de Janeiro (UFRJ).
About 85% of cases are sporadic, usually affecting people between 55 and 70 years old, with an incidence of 1 or 2 cases for every 1 million inhabitants. Between 10 and 15% are due to an inherited mutation in the prion. Also rare occurrences were recorded as a result of surgical procedures and through the use of contaminated instruments.
According to the Ministry of Health, between 2005 and 2014, 603 suspected cases of Creutzfeldt-Jakob disease were reported in Brazil, of which 55 were confirmed, 52 discarded, 92 undefined and 404 had the final classification ignored or blank.
Rapid worsening is one of the hallmarks of Creutzfeldt-Jakob disease.
Severe neurological disease progresses rapidly and inevitably leads to death. Symptoms are varied and can be characterized by aspects related to progressive dementia, which can be associated with involuntary muscle spasms, technically called myoclonus.
“From the onset of symptoms, the disease can lead to death in just over a year. Unfortunately, there is no specific treatment or cure for the time being. What can be done is only palliative care”, explains the neuroscientist from UFRJ.
According to Ferreira, Creutzfeldt-Jakob disease is very rare and there is no evidence of contagion from one person to another. “We’re still not sure what triggers the disease. Without knowing the trigger, there is no way to talk about prevention measures”, explained Sérgio.
Several hypotheses seek to explain the occurrence of errors in protein formation that lead to the development of the disease. “Mutations can occur, making it not ‘bend’ right, causing manufacturing defects.
The cell’s protein can be modified by free radicals, oxidative stress, interaction with heavy metals – there are several hypotheses. It is not known of anything that can favor the disease, such as diet or lifestyle”, says the neuroscientist.
The diagnosis can be made from several tests, including blood tests and the analysis of CSF (body fluid produced by the brain, which is also present in the spine).
The neurosurgeon and neuroscientist at the Hospital das Clínicas in São Paulo, Fernando Gomes, presenter of Correspondent Médico, from the Novo Dia newspaper, from CNN, explains that a specific feature of the disease allows for imaging diagnosis: cell destruction causes damage to the brain tissue that leaves the organ with a spongy appearance.
“Creutzfeldt-Jakob disease has some criteria that are already well established, such as the evolution to rapidly progressive dementia, a brain lesion that ends up evolving and diagnosed very clearly in MRI and brain exams, in addition to having some motor patterns ”, said Gomes.
Relationship to Mad Cow Disease
Creutzfeldt-Jakob disease has a variant (vCJD) called Human Transmissible Spongiform Encephalopathy (THS). The disease is mainly transmitted by the consumption of meat and beef products contaminated with Bovine Spongiform Encephalitis (BSE), popularly known as mad cow disease.
Mad cow disease gained visibility in the 1980s, when there was an outbreak in the UK, and 1990, when the first cases of the Creutzfeldt-Jakob variant in humans were reported. The first case in the world of probable blood transmission of the variant was confirmed by the United Kingdom and was caused by a blood transfusion by an infected donor who had no symptoms.
According to the Ministry of Health, no case of the Creutzfeldt-Jakob variant has been confirmed in Brazil to date. The injury has already been registered in countries like the United Kingdom, France, Ireland, Italy, Canada and the United States.
Reference: CNN Brasil