ASM Journals Tipsheet: March 1998

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TO RECEIVE COPIES OF ANY OF THESE JOURNAL ARTICLES OR FOR MORE INFORMATION CONTACT:

Jim Sliwa
(202) 942-9297
[email protected]

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Lyme Disease Crosses Pacific

Researchers from the National Defense Medical Center and the National Quarantine Service in Taiwan report the first laboratory- diagnosed case of Lyme disease in a human being in Taiwan. The report appears in the March 1998 issue of the Journal of Clinical Microbiology. A 45-year-old man living in Taipei visited a local private clinic in late December 1996 with complaints of an expanding skin rash on his side and recurrent attacks of swelling and pain. Blood tests indicated a high level of antibodies to Borrelia burgdorferi, the bacterium that causes Lyme disease. After appropriate antibiotic therapy, the patient recovered. "This report describes the first laboatory-confirmed case of human Lyme disease in Taiwan. The tick vector as well as the strain of spirochete responsible for transmission in Taiwan remain undetermined," say the researchers. "This report also highlights the increasing evidence of the existence of tick-borne zoonotic infections in Taiwan and the fact that new cases of Lyme disease in Taiwan can be expected." (C.-M. Shih, J.-C. Wang, L.-L. Chao, and T.-N. Wu. 1998. Lyme disease in Taiwan: first human patient with characteristic erythema chronicum migrans skin lesion. Journal of Clinical Microbiology. 36:807-808.)

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Cryptosporidium Found in Chesapeake Bay Oysters

Oysters in the Chesapeake Bay may be contaminated with the parasite Cryptosporidium parvum, say researchers from the Agricultural Research Service, the National Oceanic and Atmospheric Administration and Johns Hopkins University. Their report appears in the March 1998 issue of the Journal Applied and Environmental Microbiology.

In the study the researchers harvested oysters from six different locations around the Chesapeake Bay and tested them for the organism. Some of the oysters at all the sites were found to be contaminated. The percentage of contaminated oysters ranged from 16.7% to 60% in the spring and 6.7% to 86.7% in the summer depending on the harvest site.

Cryptosporidium parvum is a waterborne parasite that can cause severe diarrhea and gastrointestinal upset that can last over two weeks in people with competent immune systems and can be fatal in immunocompromised people. It is responsible for numerous outbreaks, including one in Milwaukee in 1993 that affected over 400,000 people. It only takes a small number of organisms to cause an infection.

Oysters are filter feeders and can pose a potential health threat by concentrating bacteria and other pathogenic organisms in polluted waters. Although no human cases of of cryptosporidiosis have been linked to the ingestion of raw shellfish in the Chesapeake Bay, this study clearly indicates that the potential is there, say the researchers. (R. Fayer, T.K. Graczyk, E. J. Lewis, J.M. Trout, and C.A. Farley. 1998. Survival of infectious Cryptosporidium parvum oocysts in seawater and eastern oysters [Crassostrea virginica] in the Chesapeake Bay. Applied and Environmental Microbiology. 64:1070-1074.)

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Female Hormones Affect Infectivity of Chlamydia

High levels of the female hormone progesterone may increase the susceptibility of the uterus to chlamydial infection, say researchers in the March 1998 issue of the journal Infection and Immunity.

The researchers from Dartmouth Medical School and Connaught Laboratories in North York, Ontario, Canada, report on a study that compares infectivity rates for Chlamydia trachomatis in female rats. The rats received either progesterone or a saline solution and then were challenged with the organism. When they were tested 14 days later for the presence of chlamydial infection, rats given progesterone were found to be infected while those given saline showed no infection.

"These findings indicate that under appropriate endocrine conditions the rat uterus is susceptible to C. trachomatis infection," say the researchers. "Our studies indicate that endocrine balance influences local immune responses which may result in either enhanced or compromised immune protection." (C. Kaushic, A.D. Murdin, B.J. Underdown, and C.R. Wira. 1998. Chlamydia trachomatis infection in the female reproductive tract of the rat: influence of progesterone on infectivity and immune response. Infection and Immunity. 66:893-898.)

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