Re: उत्तर प्रदेश India - Uttar Pradesh, Acute Encephalitis Syndrome (AES)/JE cases rise- 356 dead
Re: उत्तर प्रदेश India - Uttar Pradesh, Acute Encephalitis Syndrome (AES)/JE cases rise- 356 dead
I'm not sure if this should be posted here, but thought this might be of interest. Looks like a similar AES outbreak in 2001 in West Bengal that couldn't be diagnosed.
http://news.bbc.co.uk/2/hi/south_asia/1191004.stm
Monday, 26 February,
2001, 15:37 GMT
Panic over mystery disease outbreak
'An outbreak of a mystery brain disease in north-east India has killed at least 30 people and created panic among local residents.
Officials in Siliguri, the second largest city in West Bengal, say more than 400 people have been admitted to hospital.
Although doctors have been unable to identify the mosquito-borne disease, the symptoms - high fever, headache and nausea - resemble those of Japanese Encephalitis.
Mosquito
Rice paddies in the area provide ideal breeding grounds for mosquitoes
Doctors and nurses have joined those fleeing the city after some medical personnel died treating patients.
Specialists fly in
Specialists from India's leading institutes have been flown to Siliguri.
Blood samples have also been sent to laboratories in the United States.
Experts say Siliguri would be prone to an outbreak of Japanese Encephalitis, given the many rice paddies in the area which would allow mosquitoes to hatch freely.
There are also large pig farms close to residential areas, which would aid the spread of the virus.
Many of the victims have been children, another common hallmark of the disease.
Mosquitoes
Japanese Encephalitis causes severe swelling in the brain and is passed from animals to humans by mosquito bites.
It is prevalent in agricultural areas throughout south and east Asia, killing about 10,000 people each year.
But doctors in Siliguri say they still cannot be certain about the identity of the latest outbreak. "
Then this study below helps to explain why so many cases of AES remain undiagnosed and offers some possibilities as why it is increasing in a few countries:
http://www.virologyj.com/content/5/1/134
The incidence of acute encephalitis syndrome in Western industrialised and tropical countries
Fidan Jmor1 email, Hedley CA Emsley1 email, Marc Fischer3 email, Tom Solomon1,2 email and Penny Lewthwaite1 email
1Division of Neuroscience, University of Liverpool, Clinical Sciences Centre, Lower Lane, Liverpool, L9 7LJ, UK
2Brain Infections Group, Divisions of Neuroscience and Medical Microbiology, School of Tropical Medicine, University of Liverpool, Liverpool, L9 7LJ, UK
3Centers for Disease Control and Prevention, Atlanta, Georgia, USA
author email corresponding author email
Virology Journal 2008, 5:134
"Aetiology confirmation
No laboratory diagnostic criteria were specified in 10 studies [5,16-18,33,34,37-40]. Most studies that specified laboratory diagnostic criteria relied on a combination of complement fixation and haemagglutination inhibition in CSF and/or serum, using either single or paired specimens from different phases of each patient's infection.
Evaluating antibody titres may be problematic however, especially in young children as development of antibody, particularly in CSF may occur late [11]. Serum antibodies may indicate an associated infection rather than a causative CNS infection and could potentially lead to a falsely high incidence rate if not taken into account.
Despite extensive microbiological investigation, there was always a significant proportion of patients with no causative agent identified (28?85% unconfirmed). Two principle explanations for this might be firstly that the screening techniques used were not adequate to detect all possible causative agents, and secondly that a proportion of encephalitides, such as those due to VZV, measles virus or Mycoplasma pneumoniae, are post infectious and the causative agent might not be identifiable by the screening tests employed. In addition not all encephalitis cases are caused by microorganisms. The proportion of aetiologically confirmed acute encephalitis cases has varied in the past from 15?100% [23,25,28,30]. The commonest identified cause was HSV, with a relatively consistent incidence across the globe probably reflecting a lack of geographical specificity for herpes viruses.
....
Incidence of Encephalitis in Tropical Countries
In recent years, the epidemiology and distribution of JE has changed [52]. The disease incidence is decreasing in China, Japan and Korea, and Thailand where it appears to be associated with widespread vaccination campaigns;
in contrast it appears to be increasing in parts of Bangladesh, Burma, India, Nepal, and Vietnam [16,23,25,31,53,54]. Although the reasons for these changes are not clear, they may include the adoption of rice cultivation, establishment of larger pig farms and promotion of pig-breeding as a food source, and possibly climate changes [52]. Data from tropical countries successfully implementing vaccination, would suggest that even where JE incidence has fallen as a result, the minimum overall incidence of viral acute encephalitis in JE endemic areas is similar to that in Western industrialised countries [26,27,31], with the reported incidence of JE in the tropics ranging from 2 to 15 per 100,000.
Conclusion
From the 25 studies reviewed in detail, in the most robust, prospective studies conducted in Western industrialised and tropical countries a minimum incidence of 10.5 per 100,000 AES cases is reported for children and 2.2 per 100,000 for adults and 6.34 per 100,000 for all ages. For ease of use in protocols and as benchmarks we therefore suggest that the 2 per 100,000 be used as the minimum incidence for adults, and 10 per 100,000 for children and 6 per 100,000 for all age groups for use in future WHO AES surveillance standards.
The fact that the aetiology of acute encephalitis remains unknown in the majority of patients [15] represents a diagnostic challenge for the future. The increasing incidence of encephalitis due to emerging agents, such as JEV, WNV [19], TBEV [15], and Mycoplasma pneumoniae [49], will present additional challenges. This review shows that in most studies conducted in both Western industrialised and tropical countries, an overall incidence of acute encephalitis of between 1 and 15 per 100,000 is reported, with higher incidences in children than adults. There were no prospective studies from tropical settings looking at the incidence of acute encephalitis in children only...."
