LATE, a new type of dementia

National Institutes of Health scientists have identified a new type of dementia and have named it LATE or Limbic-predominant Age-related TDP-43 Encephalopathy as reported April 30, 2019, in the journal Brain.

LATE is an under-recognized condition and the “oldest-old” (80 years and older) are at greatest risk of developing it.

LATE affects multiple areas of cognition, ultimately impairing activities of daily life. It mimics the clinical features of Alzheimer’s disease, but is more slowly progressing. But, LATE combined with Alzheimer’s causes a more rapid decline than either condition alone would.

Now there is rising appreciation that a variety of diseases and disease processes contribute to dementia. Each condition appears differently when a brain sample is examined at autopsy. However, it has been increasingly clear that in advanced age, a large number of people had symptoms of dementia without the telltale signs in their brain at autopsy. Emerging research seems to indicate that the protein TDP-43 may contribute to that phenomenon.

The autopsy diagnosis has been suggested in three stages, according to where in the brain TDP-43 is detected:

·         Stage 1: amygdala only

·         Stage 2: amygdala and hippocampus

·         Stage 3: amygdala, hippocampus and middle frontal gyrus

TDP-43 (transactive response DNA binding protein of 43 kDa) is a protein that normally helps to regulate gene expression in the brain and other tissues. Recent research has shown misfolded TDP-43 protein as being very common in older adults. Around 25% of people over 85 years of age have enough misfolded TDP-43 protein to affect their memory and/or thinking abilities.

Unusually misfolded TDP-43 has a causative role in most cases of amyotrophic lateral sclerosis and frontotemporal lobar degeneration. TDP-43 pathology is also commonly associated with hippocampal sclerosis. The hippocampal region of brain plays an important role in memory and learning. Therefore, cognitive impairment as the symptoms of hippocampal sclerosis may appear to be very similar to the effects of Alzheimer’s disease.

(Source: NIH, April 30, 2019)

Dr KK Aggarwal

Padma Shri Awardee

President Elect Confederation of Medical Associations in Asia and Oceania   (CMAAO)

Group Editor-in-Chief IJCP Publications

President Heart Care Foundation of India

Past National President IMA

Chronic wasting disease detected in wild deer in the US: Could this be another emerging zoonosis?

Chronic wasting disease (CWD has been detected in wild deer, elk or moose in 24 states in the United States. It is a fatal progressive neurodegenerative illness, which was first identified in the 1960s and has been found in the US and Canada, Norway and South Korea.

·         It is a prion disease belonging to the same family as Creutzfeldt-Jakob disease, the human prion disease.

·         The incubation period is more than one year and some animals may be asymptomatic for years.

·         Symptoms when develop include drastic weight loss (wasting), stumbling (lack of coordination), listlessness and other neurologic symptoms. It can make them more aggressive and less afraid of human contact, according to the CDC.

·         An animal with chronic wasting disease can spread prions to other animals through direct or indirect contact with bodily fluids such as feces, saliva, blood, or urine.

·         There are no treatments or vaccines available for the disease.

The CDC has warned hunters to take precautions around potentially infected animals.

Since 1997, the World Health Organization has recommended that it is important to keep the agents of all known prion diseases from entering the human food chain.

The CDC has advised people not to handle or eat meat from deer and elk that seem sick or have been found dead. It says latex or rubber gloves should be worn when handling the meat and contact kept to a minimum, especially when handling organs such as the brain or spinal cord.

No cases of CWD have been reported in humans so far, but experimental studies have suggested a possible risk to humans and may emerge as a zoonotic disease in the future.

Wildlife disease surveillance may provide information of domestic and wild animal morbidity and mortality, identify changes in patterns of disease occurrence over time, and assist in early detection of disease outbreaks, including those linked to emerging diseases (World Organisation for Animal Health [OIE]).

Surveillance of disease in wild animals is challenging and not easy compared to surveillance in domestic animals. And, not many countries have animal health information systems and surveillance systems for animal diseases.

India has the largest number of deer species in the world. Hunting of all wild animals is banned in India under the Wildlife (Protection) Act of 1972, poaching or illegal hunting, killing or capturing of wild animals is still prevalent.

Wild animals serve as major reservoirs for transmission of zoonotic agents to domestic animals and humans.

So, it is important to be aware about the disease and prevent human exposure.

Like Nipah and Zika,  could this be another outbreak waiting to happen?

Dr KK Aggarwal

Padma Shri Awardee

President Elect Confederation of Medical Associations in Asia and Oceania   (CMAAO)

Group Editor-in-Chief IJCP Publications

President Heart Care Foundation of India

Past National President IMA