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Biological Hazard – Animal Diseases | Canine Hepatozoonosis: Oklahoma


Published Date: 2017-08-05 14:01:32
Subject: PRO/AH> Hepatozoonosis – USA: (OK) canine
Archive Number: 20170805.5229499

[American canine hepatozoonosis (ACH) is a tickborne disease that is spreading in the south eastern and south-central United States. Characterized by marked leukocytosis and periosteal bone proliferation, ACH is very debilitating and often fatal. Dogs acquire infection by ingesting nymphal or adult Gulf Coast ticks (Amblyomma maculatum) that, in a previous life stage, ingested the parasite in a blood meal taken from some vertebrate intermediate host. ACH is caused by the _apicomplexan Hepatozoon americanum_ and has been differentiated from Old World canine hepatozoonosis caused by H. canis. Unlike H. canis, which is transmitted by the ubiquitous brown dog tick (_Rhipicephalus sanguineus_), _H. americanum_ is essentially an accidental parasite of dogs, for which Gulf Coast ticks are not favored hosts. The geographic portrait of the disease parallels the known distribution of the Gulf Coast tick, which has expanded in recent years. Thus, the endemic cycle of _H. americanum_ involves _A. maculatum_ as definitive host and some vertebrate intermediate host(s) yet to be identified. Although coyotes (Canis latrans) are known to be infected, it is not known how important this host is in maintaining the endemic cycle. This review (S A Ewing, R J Panciera. American canine hepatozoonosis. Clin Microbiol Rev. 2003 Oct; 16(4): 688-697. doi: 10.1128/CMR.16.4.688-697.2003; PMCID: PMC207105) covers the biology of the parasite and of the tick that transmits it and contrasts ACH with classical canine hepatozoonosis. Clinical aspects of the disease are discussed, including diagnosis and treatment, and puzzling epidemiologic issues are examined. Brief consideration is given to the potential for ACH to be used as a model for study of angiogenesis and of hypertrophic osteoarthropathy.]

This information was obtained from the abstract to the mentioned article and was extracted from – Mod.TG


Date: Tue 1 Aug 2017
Source: Prudue Exponent [edited]

Everything seemed great for Spice, a 2 year old Australian heeler (cattle dog) rescue dog from Oklahoma. A nice woman in Indiana had just adopted her and promised her a forever home. However, things took a turn for the worst soon after moving to Indiana.

Spice developed a high fever and appeared to be in an immense amount of pain, said Andrew Woolcock, assistant professor of small animal internal medicine at Purdue University. Her owner brought her to the Purdue Veterinary Teaching Hospital, where doctors discovered that she had a very rare infectious disease caused by a protozoan called _Hepatozoon americanum_.

“It’s a disease not seen here in Indiana,” Woolcock said. “Spice’s unique set of symptoms, along with her travel history, made this rare disease a top suspect in her case and it turned out to be just that.” Dogs contract this organism after ingesting a tick containing the protozoa, Woolcock said. This is unique because most tickborne diseases are transmitted by the bite of the tick. The organisms spread primarily into the muscle tissue, causing severe inflammation and pain.

“It is a disease that can be fatal if left untreated, but Spice got here in time and we were able to treat her,” he said. Woolcock says this is the 1st time that this disease has been diagnosed and treated at the Veterinary Teaching Hospital at Purdue. “It is a disease primarily seen in the Gulf Coast states in the south and, actually, only about 15 states in the United States have reported seeing this disease,” he says.

Doctors treated Spice with a combination of anti-microbials similar to those used to treat malaria in people. Spice’s fever and pain resolved within a few days, but it may take more than a year for the dog to be fully clear of the organism. Woolcock says owners, regardless of where they live, should be vigilant about using a monthly tick and flea preventative. He also says to make sure every pet in the home is treated because if one untreated pet gets a diseased tick, the disease can be transmitted to other pets in the home.

Dr Allison Kendall, a resident in internal medicine, and Rachel Kohanov, a 4th-year vet student, helped with the case.

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