Minnesota Department of Health (MDH) Bug Bytes

Jan. 24, 2008
Vol. 9: No.1


Topics in this Issue:

1. Parrot Fever
2. Lab-acquired Brucellosis
3. What's Going on with Meningococcal Disease?
4. "Chronic Lyme Disease"
5. Outbreak of Chronic Inflammatory Neuropathy


1. Parrot Fever

On December 21, the Florida Department of Health called to report that two pet store chains in Minnesota had received birds infected with avian chlamydiosis (psittacosis in humans) from a Florida distributor. Potentially involved pet stores included Petland Shakopee, and PetSmart located throughout the state. Later the same day, Scott County Public Health reported a case to us of psittacosis in a Petland Shakopee employee. A statewide Health Alert and press release were issued and an investigation was initiated. The investigation is ongoing and testing is in progress for several potential human cases, but to date we know of at least two human cases in pet store employees. Affected birds have been returned to the distributor or have been removed from sales display areas and are being treated for the infection.

In humans, psittacosis is also known as parrot fever and is a bacterial infection acquired by inhaling dried excretions from infected psittacine birds (e.g., cockatiels, parakeets, macaws, parrots). It is caused by "Chlamydophila psittaci "Person-to-person transmission does not generally occur. The incubation period is usually 5 to 14 days, and symptoms include abrupt onset of fever, chills, headache, malaise, and myalgia. Patients typically develop a nonproductive cough that can be accompanied by difficulty breathing and chest tightness. Pneumonia is often evident on chest x-ray with lobar or interstitial infiltrates.

Diagnosis is confirmed by a four-fold rise in titer between acute and convalescent serology taken 2-3 weeks apart. Doxycycline is the drug of choice; macrolides are the best alternative in patients for whom tetracyclines are contraindicated.

Learn more about: psittacosis>>

2. Lab-acquired Brucellosis

In last week's (January 18) "MMWR "was an article about an investigation of laboratory-acquired brucellosis in which we participated (see http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5702a3.htm). On October 25, 2006 a Minnesota clinical laboratory microbiologist had onset of fever, fatigue, and night sweats. On November 9, the same laboratory where she worked identified a blood culture isolate from her as "Brucella" spp. and notified us. An investigation determined that the microbiologist had handled on an open bench two unidentified isolates subsequently identified as "Brucella" spp. Her first exposure had occurred in July while she was handling an isolate which had been forwarded from an Indiana clinical laboratory, and a second exposure had occurred in early August during testing of an isolate from a Texas referring clinical laboratory. No spills or aerosol-generating procedures had occurred.

Potentially exposed workers from the laboratory were identified, and their exposures were classified as either high risk or low risk. Thirteen were classified as high risk, including the exposure of the case-patient. All but the patient were advised to receive post-exposure prophylaxis.

To determine the source, CDC compared the patient's blood culture isolate with the isolates handled, using multiple-locus variable number tandem repeats analysis at 21 genomic regions. All isolates were identified as "Brucella melitensis" biovar 3. Matching of 17 genomic amplicons suggested that the Texas isolate was the source of infection.

Brucellosis is among the most commonly reported laboratory-acquired bacterial infections. Infections have occurred from sniffing culture plates, spilling culture bottles, mucocutaneous exposure to sprays of organism-containing suspensions, aerosol generation from ruptured centrifuge tubes, or routine laboratory work with "Brucella" cultures outside of biological safety cabinets. Because unidentified isolates are commonly manipulated on an open bench, inadvertent exposure can occur. A notification and response protocol must be used after identification of "Brucella". Exposures can be minimized by clinicians and forwarding laboratories clearly identifying specimens they suspect to be "Brucella". If "Brucella" has been identified (or is highly suspect), please notify us immediately.

Learn more about: Brucella>>

3. What's Going on with Meningococcal Disease?

In recent years we have experienced a downward trend in the number of meningococcal disease seen annually from 30 to 40, to 16 culture-confirmed cases in 2005, and 15 in 2006. However, that trend appears to be over. There were 9 culture-confirmed cases of meningococcal disease in the last 3 months of 2007 with an additional 3 culture-negative, polymerase chain reaction-positive cases. An additional 6 culture-confirmed cases have been reported just in the first 2 weeks of 2008.

No epidemiologic links have been identified for any of the recent cases. Eight of the 15 (53%) culture-confirmed cases occurring since September 2007 have been residents of the Twin Cities metropolitan area. Ages have ranged from 1 year to 92 years, with a median age of 25. Seven cases (47%) were serogroup C, 4 (26%) serogroup B, 2 (13%) serogroup Y, and one each (7%) serogroups W-135 and Z. There have been 3 deaths (ages 5, 33, and 53) and all were attributed to serogroup B.

A conjugate meningococcal vaccine for serogroups A, C, Y, and W-135 is licensed for use in 2-55 year olds and is currently recommended for all adolescents ages 11 and older.

Learn more about: Meningococcal Disease>>

4. "Chronic Lyme Disease"

Lyme disease is a tick-transmitted infection caused by "Borrelia burgdorferi". Most Lyme disease cases reported to us presented to their physicians with signs of early Lyme disease, including the characteristic erythema migrans (EM or bulls-eye rash). Untreated infection may develop into disseminated Lyme disease or into late Lyme disease, manifesting as multiple EMs, "flu-like" symptoms (such as fever, headache, fatigue, and myalgias), episodes of joint swelling, neurologic problems, or cardiac involvement. Rarely, patients treated for objective findings of Lyme disease may subsequently experience post-Lyme disease syndrome, a post-infectious process with milder, self-limited, nonspecific symptoms including fatigue, muscoskeletal pain, and/or neurocognitive problems.

A recent (October 4, 2007) "New England Journal of Medicine" article reviews the topic of "chronic Lyme disease" as do guidelines from the Infectious Diseases Society of America. "Chronic Lyme disease" is a poorly-defined term used by some patients, advocates, and practitioners for a set of persistent symptoms (including fatigue, myalgia, arthralgia, headache, and memory loss) that may or may not arise from "B. burgdorferi" infection. Chronic Lyme disease can include post-Lyme disease syndrome but has also been applied to symptoms of non-Lyme disease etiology. In addition, the diagnosis of "chronic Lyme disease" is frequently used for symptoms of unknown etiology without a history of objective signs of Lyme disease or evidence of "B. burgdorferi" infection.

Subjective and nonspecific symptoms pose challenges for clinicians whose patients request diagnosis and treatment for "chronic Lyme disease." The bulk of scientific evidence does not support the existence of persistent "B. burgdorferi" infection after antibiotic therapy or in the absence of antibodies against "B. burgdorferi"; furthermore, long-term parental antibiotic therapy used by some physicians to treat what they believe is chronic infection can lead to serious sequelae such as secondary infections and biliary disease. For patients with post-Lyme disease syndrome (a history of objectively-diagnosed and treated Lyme disease), most controlled prospective trials have not demonstrated benefit from further antibiotic treatment. Long-term antibiotic therapy is also not indicated for patients whose symptoms are more likely attributable to another diagnosis or who lack a history of objective clinical findings suggestive of Lyme disease, regardless of laboratory evidence of antibody against "B. burgdorferi".

The MDH Lyme Disease Guidelines for Minnesota Physicians are at: http://www.health.state.mn.us/divs/idepc/dtopics/tickborne/guidline.html.

Learn more about: Lyme Disease>>

5. Outbreak of Chronic Inflammatory Neuropathy

As has been widely reported in the media, we have been investigating a cluster of 12 cases of chronic inflammatory neuropathy among workers at the Quality Pork Processors (QPP) plant in southern Minnesota. Individual illnesses had onset over a period of weeks or months and were associated with the development of progressive weakness and changes in sensation resulting in moderate to severe disability. All 12 affected persons were previously healthy, were from multiple racial/ethnic backgrounds, ranged in age from 21 to 51 years (median: 37 years), and included males and females. Onsets of illness began in December 2006 and continued into December 2007.

The plant employs approximately 1,100 workers, who slaughter and process about 18,000 pigs daily. All of the cases either worked at or near the table where severed pig heads were processed, or could be linked to the table. We are investigating a possible role for a procedure that uses high-pressure air to remove brains from the swine head. The cases had no common associations outside the workplace.

In cooperation with CDC and other states, we have visited other plants in Indiana, Illinois, and Nebraska. The Indiana Department of Health and CDC are investigating illnesses in several plant workers at a pig slaughtering plant there to determine if the illnesses are similar to what has been found here in Minnesota.

MDH is actively investigating this cluster to identify the cause including exposures to toxins, swine tissue (particularly nerve tissue), and swine infections (pathogens and commensal organisms). To date, no viral pathogens have been identified. Similarly, bacterial cultures have yielded no conclusive results. MDH is partnering with investigators at CDC, NIOSH, other state health departments, the Mayo Clinic, the University of Minnesota, the Minnesota Veterinary Diagnostic Laboratory, and experts around the country to determine the cause of these illnesses.

Learn more about: Quality Pork Processor Worker Illnesses>>

Bug Bytes is a combined effort of the Infectious Disease Epidemiology, Prevention and Control Division and the Public Health Laboratory Division of MDH. We provide Bug Bytes as a way to say THANK YOU to the infection control professionals, laboratorians, local public health professionals, and health care providers who assist us.

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Updated Friday, 19-Nov-2010 14:16:52 CST