S. japonicum

Schistosoma japonicum, the Blood Fluke

Introduction: S. jasponicum is mostly found in the Far East [1]. It is also found in various parts of Southeast Asia and the Western Pacific countries. They are consisted digenic trematodes due to that fact that they have two host involved in their life cycle [2]. They can infect human with a disease called Katayama Fever. This is a disease that has lots of side effects but is something that is treatable.

Symbiont Description: S. japonicum cercaria look like flatworms with fishtails. They are approximately 200 by 70 micrometers. It grows to be about 15mm in length. Males are consisted shorter compared to the females. They consist of strong suckers around the mouth to attach to the host easily. S. japonicum also have sensory organs that help in resisting and avoiding the vertebrate immune system. [3]

Host Description: There are two hosts that are needed in the life cycle of S. japonicum. It consists of intermediate host, which is an aquatic snail. The snail that they use is Onchomelania hupensis. The definitive hosts are humans. It could also be any vertebrate that is wild, such as cattle, dogs, pigs, rodents. [2]

Life Cycle: Eggs are released in feces. The eggs are hatched and release miracidia under correct conditions. The miracidias swim and penetrate through snail intermediate hosts. S. japonicum produces two generations of sporocysts and produce cercariea in the snail. The cerariaes are released from the snail, which they are free swimming in the water. Humans come into contact and cerariae goes through the human skin. They are found in the superior mesenteric veins that are draining to the small intestine. Eggs move towards the lumen of the intestine, which eventually leads to leaving the human body through the feces. [1]

Ecology: A number of disease have infected host because of the large number of eggs that are produced inside of the vertebrate. S. japonicum can lead to Katayama fever, which is an acute schistosomiasis. This disease causes fever, cough, abdominal pain, diarrhea, hepatosplenomegaly, and eosinophilia. Cerebral granulomatous disease may be caused by ectopic S. japonicum eggs in the brain. There are treatments to help with the diseases that are transferred from S. japonicum. [1]

Example of Water-Born Transmission: It can be seen that the transmission of the S. japonicum is through the water. To move from one host to the next, the parasite swims through the water and infects each host.

Reference:

[1] "Schistosomiasis." DPDX. CDC, 23 Feb. 2010. Web. 27 Feb. 2012. <http://dpd.cdc.gov/dpdx/html/Schistosomiasis.htm>.

[2] "Schistosoma Japonicum." Schistosoma Japonicum, Blood Fluke: Taxonomy, Facts, Life Cycle at MetaPathogen. 22 Apr. 2011. Web. 27 Feb. 2012. <http://www.metapathogen.com/schistosoma/schistosoma-japonicum.html>.

 [3] Green, S. 2001. "Schistosoma japonicum" (On-line), Animal Diversity Web. Accessed February 27, 2012 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Schistosoma_japonicum.html