Todayโs path rounds are on ๐๐ฆ๐๐ซ๐ข๐๐๐ง ๐ก๐๐ฉ๐๐ญ๐จ๐ณ๐จ๐จ๐ง๐จ๐ฌ๐ข๐ฌ!
๐๐ก๐๐ญ ๐ข๐ฌ ๐ข๐ญ?
๐๐๐ฉ๐๐ญ๐จ๐ณ๐จ๐จ๐ง๐จ๐ฌ๐ข๐ฌ is infection by ๐๐๐ฉ๐๐ญ๐จ๐ณ๐จ๐จ๐ง species, where are a genus of ๐๐ฉ๐ข๐๐จ๐ฆ๐ฉ๐ฅ๐๐ฑ๐๐ง๐ฌ. Apicomplexans are a type of parasite that must live within the cells of their hosts in order to survive.
๐๐ก๐จ ๐ ๐๐ญ๐ฌ ๐ข๐ญ?
This disease affects dogs! This particular disease is most common in the southern United States.
๐๐ก๐๐ญ ๐๐๐ฎ๐ฌ๐๐ฌ ๐ข๐ญ?
American hepatozoonosis is caused by ๐๐๐ฉ๐๐ญ๐จ๐ณ๐จ๐จ๐ง ๐๐ฆ๐๐ซ๐ข๐๐๐ง๐ฎ๐ฆ. This parasite is spread by ๐๐๐ญ๐ข๐ง๐ ticks, not being bit by the tick! Weird.
Within the tick, Hepatozoon undergoes reproduction to produce ๐ฌ๐ฉ๐จ๐ซ๐จ๐ณ๐จ๐ข๐ญ๐๐ฌ. An animal will eat the tick, and the sporozoites will be released into the intestines, migrate through the intestinal wall, and enter the bloodstream. Once in the bloodstream, the parasite makes a home for itself in ๐ฅ๐๐ฎ๐ค๐จ๐๐ฒ๐ญ๐๐ฌ (white blood cells), which allow it to be spread throughout the body. The parasites will then undergo further development in many tissues, including the liver and skeletal muscle.
๐๐ก๐ฒ ๐ข๐ฌ ๐ญ๐ก๐ข๐ฌ ๐ ๐ฉ๐ซ๐จ๐๐ฅ๐๐ฆ?
When the parasites set up shop in the muscle or liver, they induce a strong immune response. This immune reaction causes fever, depression, anorexia, soreness, and stiffness for the animal. Often affected dogs have such severe muscle soreness they become unwilling to move at all, even to eat or drink! All because of a little friend hanging out in their muscle cells 
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐๐ข๐๐ ๐ง๐จ๐ฌ๐๐?
The best method of diagnosis is a ๐ฆ๐ฎ๐ฌ๐๐ฅ๐ ๐๐ข๐จ๐ฉ๐ฌ๐ฒ, where a pathologist can look at the tissue under a microscope and see the little parasites hanging out in the cells. Often, these parasites can also be seen on a ๐๐ฅ๐จ๐จ๐ ๐ฌ๐ฆ๐๐๐ซ within the leukocytes, which can help make the diagnosis prior to sending off tissues.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐ญ๐ซ๐๐๐ญ๐๐?
Unfortunately this infection is considered to be a lifelong condition, with no treatment methods causing complete clearance of the parasite. Patients are often given long-term pain medications and antiparasitic medications to help control the disease, but the efficacy is rather poor.
๐๐ก๐จ๐ญ๐จ๐ฌ
1-2) ๐๐๐ฎ๐ญ๐ซ๐จ๐ฉ๐ก๐ข๐ฅ๐ฌ, one of the main clean-up cells, containing Hepatozoon. They kinda look like a cartoon bacteria 
3-5) What a pathologist might see in a muscle biopsy under the microscope!
๐๐จ๐ฎ๐ซ๐๐๐ฌ
Maxie, G. Jubb, Kennedy and Palmerโs Pathology of Domestic Animals, Volume 1. Sixth Edition.
Photos 1-5 ยฉ Noahโs Arkive contributors Labranche, Harvey/Raskin, King licensed under CC BY-SA 4.0.
