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→Life cycle and Transmission
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==Learning resources==
*旋毛虫 in Japanese
*[https://www.trichinella.org/home THE TRICHINELLA PAGE]
*[https://www.cdc.gov/dpdx/trichinellosis/index.html Trichinellosis - DPDx by US CDC]
*[http://www.ichiryusha.com/book/index.php?main_page=product_info&cPath=23&products_id=1154 Illustrated ''Trichinella'' written by Yuzo Takahashi] (not for sale)
==Pathogen and Taxonomy==
**Pigs and rats (domestic cycle) or wild bores, wild bears, polar bears, rats and birds (sylvatic cycle).
**Humans are '''accidental (deadend) hosts''' for ''Trichinella''
**'''Only humans develop clinical symptoms by ''Trichinella'' infection'''*Refer to [https://www.cdc.gov/dpdx/trichinellosis/index.html DPDx - Trichinellosis - US CDC]
https://www.cdc.gov/dpdx/trichinellosis/modules/Trichinella_LifeCycle.gif
*Transmission to human occurs by ingestion of raw or undercooked meat including '''pigs''', '''wild bores''', '''horse''', '''dog''', '''bear''', '''polar bear''', '''badger''' and '''soft-shelled turtle (スッポン)'''.
*Transmission to horse (obligate grazer) is speculated that pasture or hay may be accidentally contaminated by infected carcass (rodents etc.).
{{quote|content=
*'''The world-first report''' of trichinellosis originated from '''soft-shelled turtle''' was published in Japan in 2009 (but only in Japanese and neglected from English literature).
*The transmission route is speculated that soft-shelled turtles were fed by carrions of pigs dead by diseases and contaminated through the carrions.
{{quote|content=
前田卓哉, 藤井毅, 岩本愛吉, 長野功, 呉志良, & 高橋優三. (2009). スッポンを感染源とする旋毛虫症例. 病原微生物検出情報, 30(10), 272–273. https://idsc.niid.go.jp/iasr/30/356/kj3563.html
}}
*Report of trichinellosis outbreak through game bear meat in Japan.
{{quote|content=
海野友梨, 中本有美, & 深谷節子. (2017). 茨城県内で発生した旋毛虫による食中毒事例について. 茨城衛生研究所年報, 55, 37–41. https://www.pref.ibaraki.jp/hokenfukushi/eiken/kikaku/annualreport/documents/32_senmoutyu.pdf
}}
##Weeks after infection, larvae encyst in striated muscles they arrived
##Cachexia, edema, extreme dehydration
##In 6 months calcification of cysts takes place ##Inside calcified cysts, '''<nowiki>'</nowiki>nurse cells<nowiki>'</nowiki>''' which is transformed from normal striated muscle cells by larvae secretion encapsulate and nourish larvae##'''Encapsulated larvae die can survive months to decades inhuman striated muscles'''
*The larger number of larvae infect, the more severe symptoms are
**<10 larvae: asymptomatic to mild
**50-500 larvae: moderate
**<1000 larvae: severe to fatal
===Nurse cell===
*Refer to [https://www.trichinella.org/the-nurse-cell Nurse cell formation in THE TRICHINELLA PAGE] or the following article
{{quote|content=
Wu, Z., Sofronic-Milosavljevic, L., Nagano, I., & Takahashi, Y. (2008). Trichinella spiralis: nurse cell formation with emphasis on analogy to muscle cell repair. Parasites & Vectors, 1(1), 27. https://doi.org/10.1186/1756-3305-1-27
}}
==Diagnosis==
{|class="wikitable" style="width:800px"
|+Case definitions by ECDC
|-
*Epidemiological link to laboratory-confirmed human case with the common source
|}
{{quote|content=
Gottstein, B., Pozio, E., & Nöckler, K. (2009). Epidemiology, Diagnosis, Treatment, and Control of Trichinellosis. Clinical Microbiology Reviews, 22(1), 127–145. https://doi.org/10.1128/CMR.00026-08
}}
*'''Trichinoscopy'''
**Encystment phase begins 1 week after infection at the shortest
**Muscle biopsy specimen is thin-sliced and pressed between two slides without any stain and cysts are observed
*ELISA for antibody detection is common
*Multiplex PCR is also used
===Differential diagnoses===
*Trichinellosis is a great mimicker
**Typhoid, encephalitis, myositis, tetanus, Katayama syndrome, hookworm infection, strongyloidiasis, periarthritis nodosa, rheumatoid arthritis
==Treatment==
*Albendazole and mebendazole
==Prevention and Control==
{|class="wikitable"
|-
!style="width:50%"|Heat
!style="width:50%"|Freezing
|-
|rowspan="2"|
*Meat core temperature '''≥71°C '''for''' ≥1 min'''
**Color to gray, muscle fibers separated
|
Up to '''15cm thickness''' meat block
*'''≤-15°C '''for''' ≥3 weeks'''
|-
|
Up to '''50cm thickness''' meat block
*'''≤-15°C '''for''' ≥4 weeks'''
|-
|
|※'''Applicable only to ''T. spiralis'' in pork'''
|}
※Other species are more resistant to cold temperature
*''T. britovi'' in pork survived for 3 weeks at -20°C
*''T. spiralis'' in horse survived for 4 weeks at -18°C
*Game meat like bear harbors freeze-resistant ''Trichinella''
**5 years in bear meat
