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Published Date: 2012-08-11 14:33:13
Subject: PRO/AH/EDR> Anaplasmosis - USA: (ME) increased incidence
Archive Number: 20120811.1239966

ANAPLASMOSIS - USA: (MAINE) INCREASED INCIDENCE
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Date: Fri 10 Aug 2012
Source: Bangor Daily News [edited]
http://bangordailynews.com/2012/08/09/health/another-tick-borne-disease-emerges-in-maine/

Maine is seeing record numbers of a disease carried by ticks that doesn't get as much attention as Lyme disease, but can be just as dangerous.

So far this year, 38 cases of the bacterial infection anaplasmosis have been reported in Maine, according to a Thursday [9 Aug 2012] alert from the Maine Center for Disease Control and Prevention. That's more than all of 2011, when Maine had 26 cases of the disease. The infection is caused by a germ called _Anaplasma phagocytophilum_.

"Everybody's heard about Lyme disease but they maybe haven't heard about anaplasma," said Dr. Stephen Sears, state epidemiologist. Carried by the same deer tick as Lyme disease, anaplasmosis is no longer rare in Maine like it was a few years ago, he said. "It seems to be increasing not only in the numbers but in its distribution," Sears said. "It's being seen a little farther up the coast and a little deeper into the interior sections."

Anaplasmosis has been found in Androscoggin, Cumberland, Hancock, Kennebec, Knox, Lincoln, Somerset and York counties so far this year. Other parts of the country that have high rates of Lyme disease are also seeing anaplasmosis on the rise, Sears said.

Some ticks can carry [the microorganisms that cause] both anaplasmosis and the Lyme [disease, _Borrelia burgdorferi_], as well as another less common disease called babesiosis [, _Babesia microti_].

While the drug treatment for anaplasmosis is similar to the treatment for Lyme disease, the infection doesn't cause Lyme's hallmark bull's eye rash, Sears said. It's a different organism that leads to severe flu-like symptoms, such as body aches, fever and headache, he said.

The disease can be diagnosed through a blood test, and the sooner sufferers get treatment, the better, Sears said. _Anaplasma_ lives in white blood cells, causing all-over discomfort as the cells circulate through the body, he said. Symptoms typically appear within one to two weeks of a tick bite. The disease can be serious in people with weak immune systems, he said.

Most anaplasmosis occurs in the late summer and fall, so cases are predicted to keep rising, he said. "We're expecting that this is going to be a pretty big year, so we want to get the word out," Sears said.

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[The deer tick, _Ixodes scapularis_ transmits _Anaplasma phagocytophilum_. a rickettsia-like Gram-negative, obligate intracellular bacterium that causes human granulocytic anaplasmosis, as well as the organisms that cause Lyme disease (_Borrelia burgdorferi_) and babesiosis (_Babesia microti_). Because of a common tick vector, a patient infected with any one of these pathogens may be co-infected with other pathogens that this tick vector may be concurrently carrying.
It is not surprising to see an increased incidence of anaplasmosis in the U.S. state of Maine, because the number of Lyme disease cases in Maine has increased steadily since 2000 and expanded from the coastal to more inland counties, a phenomenon that is consistent with ecological studies tracking changes in deer tick populations in this state (http://lymebook.com/blog/geographic-incidence/lyme-disease-in-maine-statistics-cases/ and http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5837a2.htm). (See ProMED-mail post Lyme disease - USA: (ME) increased incidence 20100406.1106.)

Anaplasmosis should be suspected in patients with the acute onset of unexplained fever, chills, muscle aches, and headache, often in association with thrombocytopenia, leukopenia, and/or increased liver enzyme levels with a history of possible or known tick exposure in an endemic region within the prior 3 weeks. Some individuals who become infected with _A. phagocytophilum_ do not become ill or experience only very mild symptoms and do not seek medical treatment.

However, half the symptomatic patients require hospitalization. The symptoms tend to be most severe in aged and immunosuppressed people. Severe complications include a septic or toxic shock-like syndrome, coagulopathy, acute respiratory distress syndrome, acute abdominal syndrome, rhabdomyolysis, myocarditis, acute renal failure, hemorrhage, brachial plexopathy, demyelinating polyneuropathy, cranial nerve palsies, and opportunistic infections. Approximately 5 to 7 percent of patients require intensive care, and the disease can be fatal.

The presence of the characteristic bull's eye skin rash (erythema migrans) suggests co-infection with Lyme disease, and hemolytic anemia suggests co-infection with babesiosis.

Wright stains of peripheral blood smears or buffy-coat preparations demonstrate cytoplasmic inclusions consisting of vacuolar microcolonies of _A. phagocytophilum_ within neutrophils in 20 to 80 percent of patients with anaplasmosis, unlike the rarity of visualizing organisms within circulating mononuclear cells in patients with human monocytotropic ehrlichiosis (Weinberg G: Laboratory diagnosis of ehrlichiosis and babesiosis. Pediat Infect Dis J 2001; 20: 435-7). Most cases of ehrlichiosis have been reported from the southern and south-central United States, corresponding to the geographic distribution of the tick vector, _Amblyomma americanum_ (the tick vector for Erhlichia chaffeenisis, the cause of human monocytotropic ehrlichiosis).

The diagnosis of anaplasmosis can be confirmed by a 4-fold increase in antibody titer by IFA (indirect immunofluorescent assay) in acute and convalescent phase serum samples, PCR (polymerase chain reaction) amplification of anaplasma DNA in a clinical specimen, immunostaining of _A. phagocytophilum_ antigen in a tissue sample, or isolation of _A. phagocytophilum_ from a clinical specimen in cell culture (Centers for Disease Control and Prevention. Ehrlichiosis/Anaplasmosis 2008
Case definition. September 2008 [date cited] Available at
http://www.cdc.gov/ncphi/disss/nndss/casedef/ehrlichiosis_2008.htm).

Because _A. phagocytophilum_ is disseminated in the blood stream, it is not surprising that infected blood can serve as a vehicle for person-to-person transmission. Indeed, _A. phagocytophilum_ can survive in refrigerated blood, and anaplasmosis has been transmitted through blood transfusion (Centers for Disease Control and Prevention. _Anaplasma phagocytophilum_ Transmitted Through Blood Transfusion -- Minnesota, 2007. MMWR 2008; 57: 1145-8. October 2008 [date cited] Available from human granulocytic anaplasmosis human granulocytic anaplasmosis http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5742a1.htm).

Treatment with doxycycline 100 mg twice daily orally or intravenously for 10 days for all symptomatic patients suspected of having anaplasmosis is recommended for a minimal total course of 10 days. This treatment regimen should be adequate therapy for patients with anaplasmosis alone and for patients who are co-infected with Lyme disease, but is not effective therapy for patients who are co-infected with babesiosis.

The northeastern state of Maine can be located on the HealthMap/ProMED-mail interactive map at http://healthmap.org/r/00B0. A map of Maine counties can be found at http://quickfacts.census.gov/qfd/maps/maine_map.html. - Mod.ML]

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