Organismal

Intro

Japanese encephalitis virus, a flavivirus, related to West Nile is transmitted to humans through the bite of infected Culex species of mosquito, particularly Culex tritaeniorhynchus.^[1]

The virus is maintained between mosquito and host, particularly pigs and wading birds (See reservoir species). The virus does not amass in high enough quantities or concentrations to re-infect another host and is thus considered a “dead-end” host. ^[1]

The transmission occurs primarily in rural agricultural areas, more so standing water areas such as in rice productions. In some areas of Asia, these types of areas approach urban areas with associated with a higher risk of human infection. ^[1]

In more temperate areas of Asia, JE transmission is seasonal with peaks in the summer and fall. Transmission can occur year-round in the tropics with peaks during the rainy season. ^[1]

The Organism 

http://www.bt.com.bn/frontpage-news-national/2013/11/15/6-new-je-cases-reported

Kingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Diptera

Family: Culicidae

Genus: Culex

Species: C. tritaeniorhynchus

Relevant biological information:

- Egg to adult stage takes 6 – 10 days^[2].

- Larval habitat: low lying flooded areas, wells, ponds, ditches and water storage containers in houses^[2].

The Virus and Who is Affected

Zoonotic: Disease that can be passed between animal and human (aka vector-borne illness).

Enzootic: Affecting a species in a particular locality^[2].

Reservoirs and amplifying species: pigs, warding birds, and some bats. Incidental hosts: cattle, water buffalo, sheep, dogs, chickens, ducks, and humans.

Risk factors: coming into contact with: blood, saliva, urine, or feces of an infected animal, *being bitten by a vector host (C. tritaeniorhynchus mosquito)^[2].

Environmental factors: increased risk depends on factors such as season, duration, location, and activities.

Disability-adjusted life year for Japanese encephalitis per 100,000 inhabitants in 2002.

Symptoms

Clinical illnesses are uncommon, only affecting less than 1% of those infected^[1].

The incubation time (time from infection to illness) is typically 5-15 days^[1]..

The initial symptoms include: fever, headache, vomiting, weakness, and changes in mental status as well as movement disorders. Seizures are common^[1]..

Treatment

Specific treatments have not been found to benefit patients with JE; though hospitalization is generally required^[1]..

Outcome

Among patients who develop encephalitis, 20- 30% die. Those whose symptoms improve after a short period of time, 30-50% have lingering neurologic, cognitive, or psychiatric symptoms^[1].

Integration

While Japanese Encephalitis (JE) is very deadly and worthy of global efforts from education to effective means of treatment and control, it is only affecting a small population in rural communities of Southeast Asia. This may seem unimportant as far as global health (or a pandemic) is concerned, or that the affected are too minimal to worry about it going mainstream, the mortality rate for JE is roughly 25% including post-illness complications; which makes further research more than justifiable. Furthermore, assuming that people local to the region are aware, educated, and vaccinated (which they are to degrees) the problem globally occurs in unsuspecting individuals such as traveling tourists contract the disease or further the spread of it by transporting host species to other areas of the world.

            Japanese Encephalitis affects the host at the molecular level, specifically targeting RNA machinery. Endocytosis is a cellular process in which one cell engulfs a foreign body such as in defense against intruders or phagocytosis. The JE virus is able to bind a receptor on a cells membrane that ultimately allows entry into the cell. Once the mechanism is thoroughly understood, increased effectiveness of vaccinations and treatments can be further researched. The research goes into promising efforts of disrupting lipid rafts that once blocked could essentially render the virus innate.

            The organismal section was the most pertinent section of our presentation as it included identifying examples of who’s at risk and how to protect yourself from being infected. It is shown that one species of mosquito (C. Tritaeniorhynchus) is chiefly responsible for transmitting the disease between hosts (referred to as the vector). In this section also, the signs and symptoms are generally explained and give a brief understanding of the progression that results in complications involving the brain and sometimes results in fatalities. The epidemiology of the disease and the areas this species of mosquito resides is important in determining the allocation of resources and education. If we can educate the local population, they can protect their livestock (the reservoir host species mainly), and in turn protect themselves. The spread of the disease is made important as referenced in the ecological section because temperate climates (those ideal to C. Tritaeniorhynchus) are of increasing concern as global climate change continues.

            The ecology section focused more on the different animals affected and either their direct or indirect interactions with each other. As mentioned above the virus perpetuates itself from species to species and this method can prove dangerous if animals endemic to one region start interacting with species of another. As known of mosquitos and their choice larval habitat outlined here, increasing areas of flooding or irrigation based farming such as rice fields support a growing world population so does the breeding ground of this particular species of mosquito. This notion of increased human population also could affect the need for more livestock which as can be imagined could increase the reservoir host populations and is noted in this section. The prevention of the spread of the disease is made important, but is also noted to be difficult in controlling wild species such as birds or bats.

            The public health page sums it up by giving statistical evidence of who’s at risk and how exactly they might protect themselves. The point though isn’t to scare people from visiting regions of the globe with disease scares, it is to educate them to be sensitive to areas they are uneducated about. This section details the four types of vaccinations that are available and the relative frequencies they are to be taken. It also goes into general best practices in caring for your family and being educated in the case of an outbreak or bio-terrorism threat as outlined by the CDC. The goal of this section is to be prepared ultimately to mitigate the severity of symptoms and other potential threats involving this disease.


References cited on this page:

[1] Cdc.gov,. (2015). Transmission of Japanese Encephalitis Virus | Japanese Encephalitis | CDC. Retrieved 4 December 2015, from http://www.cdc.gov/japaneseencephalitis/transmission/index.html

[2] Reuben, Rachel (1971-10-30). "Studies on the Mosquitoes of North Arcot District, Madras State, India Part 5. Breeding places of the Culex vishnui group of species". Journal of Medical Entomology 8 (4): 363–366. doi:10.1093/jmedent/8.4.363. ISSN 0022-2585. PMID 4400663.

[3] "Japanese encephalitis world map - DALY - WHO2002" by Lokal_Profil. Licensed under CC BY-SA 2.5 via Commons - https://commons.wikimedia.org/wiki/File:Japanese_encephalitis_world_map_-_DALY_-_WHO2002.svg#/media/File:Japanese_encephalitis_world_map_-_DALY_-_WHO2002.svg