Encephalomyelitis. Synopsis. Armando Angel Biology 490 May 14, What is it?

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1 Encephalomyelitis Armando Angel Biology 490 May 14, 2009 Synopsis What is it? Taxonomy Etiology Types- Infectious and Autoimmune Epidemiology Transmission Symptoms/Treatments Prevention What is it? Inflammation of the brain and the spinal cord Different from meningitis For simplicity s s sake, the disease will be referred to as encephalitis unless otherwise noted 1

2 Types Infectious Encephalomyelitis -Commonly caused by viral infection -Usually tick-borne or mosquito borne Post-infectious/autoimmune encephalomyelitis -Due to infection, autoimmune response ensues Taxonomy/Nomenclature Japanese, St. Louis, and Tick-borne Encephalitis viruses -Family Flaviviridae -These viruses are antigenically related Western and Eastern Equine Encephalitis viruses -Family Togoviridae -Genus Alphavirus -All are arboviruses (arthropod-borne) Taxonomy cont. Mosquitoes: Phylum Arthropoda Class Insecta Order Diptera Family Culicidae Ticks: Phylum Arthropoda Class Arachnida Order Acari Family Ixodidae Vector Species: Culex pipiens Vector Species: Ixodes ricinus 2

Japanese Encephalitis Transmitted by Culex tritaeniorhynchus Endemic to most countries of Southeast Asia It is transmitted by mosquitoes who feed on birds or pigs that have the JEV and then

gov( www.cdc.gov) Symptoms include high fever, neck stiffness, convulsions, coma and spastic paralysis No treatment available. Only supportive therapy available. Figure 1. Picture of C.

3 Japanese Encephalitis Transmitted by Culex tritaeniorhynchus Endemic to most countries of Southeast Asia It is transmitted by mosquitoes who feed on birds or pigs that have the JEV and then transmitted to humans when feeding 30,000-50,000 cases of JE are reported annually ( Symptoms include high fever, neck stiffness, convulsions, coma and spastic paralysis No treatment available. Only supportive therapy available. Figure 1. Picture of C. tritaeniorhynchus Figure 2. Distribution of Japanese Encephalitis from Source: Tsai et al St. Louis Encephalitis Transmitted by several members of the Culex genus. Includes the species nigripalpus in Florida, pipiens and quinquefasciatus in the Western U.S. Distributed through the U.S., Canada, the Caribbean and parts of South America. Transmitted by mosquitoes who feed on birds infected with the virus and then transmitted to humans. 4,651 cases have been reported from 1964 to 2005 ( Symptoms are similar to Japanese Encephalitis No treatment nor vaccine available. Only supportive therapy. Figure 3. Picture of C. pipiens 3

Figure 4. Map showing the distribution of cases of St.

One vector species is Ixodes ricinus, also known as the sheep tick.

Far-Eastern tick-borne encephalitis Endemic to many parts of Europe and Russia.

4 Figure 4. Map showing the distribution of cases of St. Louis Encephalitis in the Courtesy of CDC Tick-borne Encephalitis Transmitted by ticks from the genus Ixodes. One vector species is Ixodes ricinus, also known as the sheep tick. Another is Ixodes persulcatus Three virus subtypes exist: Western or European tick-borne encephalitis virus, Siberian tick-borne encephalitis virus, Far-Eastern tick-borne encephalitis Endemic to many parts of Europe and Russia. Transmitted by ticks who feed on small rodents infected with virus who then feed on humans. Also, can be contracted by drinking raw sheep or goat milk. Can also be accompanied by symptoms of meningitis More than 10,000 cases reported throughout Europe annually ( No treatment, just supportive therapy Figure 5. Picture of I. ricinus on human skin Figure 6. Map showing distribution of tick type in Europe, Russia, and p Of Asia. Source: Lyme and Tick-borne Diseases Research Center 4

Eastern Equine Encephalitis Culiseta melanura harbors EEEV, but not responsible for transmission.

to humans and horses and some birds as well. Endemic to the Eastern U.S.

gov) Up to 90% mortality rate in horses and 33% in humans (Franklin et al 2002).

melanuta Figure 9. Map showing distribution of EEE in humans throughout the U.S. by state.

5 Eastern Equine Encephalitis Culiseta melanura harbors EEEV, but not responsible for transmission. Mosquitoes that belong to genus Culex, Aedes, and Coquillittedia feed on infected birds and act as a bridge that transmit the virus to humans and horses and some birds as well. Endemic to the Eastern U.S. and considered one of the most serious mosquito borne diseases. 220 confirmed cases from ( Up to 90% mortality rate in horses and 33% in humans (Franklin et al 2002). Vaccines available for horses but no treatment for humans. Figure 7. Picture of dead horse due to EE Figure 8. Picture of C. melanuta Figure 9. Map showing distribution of EEE in humans throughout the U.S. by state. Courtesy of CDC Western Equine Encephalitis Spread primarily by Culex tarsalis and some mosquitoes from the genus Aedes Occurs primarily in the West Coast of the U.S. (West of Mississippi) Similar to EEE, but not as virulent Mortality rate in humans is only about 4% 639 reported cases since 1964 ( Figure 10. Picture of C. Tarsalis 5

Demyelination of CNS Encephalomyelitis Disseminata -better known as Multiple

6 Figure 11. Map showing human cases of WEE throughout the U.S. by state. Courtesy of CDC Autoimmune Types Acute Disseminated Encephalomyelitis (ADEM) Demyelination of CNS Encephalomyelitis Disseminata -better known as Multiple Sclerosis Figure 12. Trash such as cans and jars can be breeding ground for mosquitoes. Larvae are present in jar 6

7 Figure 13. Discarded tires can be a breeding ground too. Prevention Vaccination (JE) Insecticide to infested areas Insect repellent containing DEET Avoid nighttime activity where mosquitoes reside Long-sleeve shirts, pants. Use your head! Conclusion What is it? Taxonomy Etiology Types- Infectious and Autoimmune Epidemiology Transmission Symptoms/Treatments Prevention 7

8 Literature Cited Center for Disease Control and Prevention Arboviral Encephalitides. Accessed online at Columbia University Medical Center. Tick-borne Encephalitis. Accessed online at Franklin, R.P., H. Kinde, M.T. Jay, L.D. Kramer, E.N. Green, R.E. Chiles, E. Ostlund, S. Husted, J. Smith and M.D. Parker Eastern Equine Encephalomyelitis Virus Infection in a horse from California. Emerging Infectious Diseases 8: Tsai, T.R., G.W. Chang, and Y.X. Yu Japanese encephalitis vaccines. Vaccines 3:

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