Infectious Disease Alert Updates
By Carol A. Kemper, MD, FACP
Dr. Kemper reports no financial relationships relevant to this field of study.
TB Quant Problematic in Leprosy
SOURCE: Rendini T, Levis W. Quantiferon-Gold tuberculosis test cannot detect latent tuberculosis in patients with leprosy. Clin Iinfect Dis 2015;61:1439-1440.
Preliminary data suggest that Quantiferon-Gold tuberculosis (TB) testing may be falsely positive in some patients with leprosy — and falsely negative in others. These authors assessed Quantiferon-Gold TB test results in 50 patients with leprosy at the New York Hansen’s Disease Program at Bellevue Hospital. Of the 50 patients, 10 had paucibacillary disease (classified BT) and 40 had multi-bacillary disease (classified as BL or LL). Five patients (10%) had positive Quantiferon-Gold TB tests — all five had paucibacillary disease, and all had negative chest radiographs. Four of these patients were born outside the United States, and one was born in Pennsylvania. None of the patients with multi-bacillary disease were positive, although they were certainly at risk for latent TB. Two of the five paucibacillary patients with positive Quantiferon-Gold tests “seroreverted” their TB blood test during multi-drug treatment for leprosy.
Laboratory data show that the TB blood test is 100% cross-reactive with two epitopes of M. leprae: the ESAT6 and the CFP10 antigen. Therefore, patients with paucibacillary leprosy, who exhibit intact cell-mediated immunity to M. leprae antigens, will cross-react with the Quantiferon-Gold test. On the other hand, patients with LL leprosy, who exhibit M. leprae anergy, will fail to mount an appreciable response to TB antigens. In other words, the TB Quantiferon-Gold test is not reliable in patients with multibacillary TB to rule out latent or active TB.
The authors indicate that both ESAT6 and CFP10 exhibit significant differences in amino acid sequences from their TB cousins — but they are apparently similar enough in their three-dimensional profile to trigger T cell activation. Researchers have speculated whether these antigens could be useful in developing a leprosy vaccine.
Trapping Flu Particles
SOURCE: Australian Associated Press. UK scientists hail creation of “flu trap.” March 21, 2016.
Researchers at the University of Manchester have developed a specialized sugar coating on fabrics to adhere to viral particles responsible for influenza. Influenza virus can survive on surfaces for 2-8 hours, depending on temperature and humidity, where they remain potentially infectious if touched by hands and carried to mucous membranes. However, these investigators created a way to anchor glycoprotein structures to cotton fabric, mimicking the glycoproteins of cells lining the respiratory tract. The influenza virus particles adhere to these glycoproteins. Studies show that 99% of viral particles that came in contact with the fabric were effectively ensnared, slowing their spread through air.
Using this “sugary coating,” such fabrics could theoretically be used to coat ventilator systems or respirators. Theoretically, similar technologies could be used to capture other viruses, such as coronavirus or SARS.
An Old Scourge Revisited: Congenital Syphilis
SOURCE: ProMED-mail post, Syphilis — USA: (California) Pregnant women, congenital, rising incidence, April 1, 2016; Syphilis — USA(03): (California) pregnant women, congenital, rising incidence; March 13, 2016.
“What contagion does thus invade the whole body, so much resist medical art, becomes inoculated so readily, and so cruelly tortures the patient?”
–Desiderius Erasmus, 1520.
I’ve never seen so many cases of syphilis — an amazing variety of secondary rashes, and even individual cases of osteomyelitis involving the radius, uveitis, and neurosyphilis. ProMED-mail has been doing a nice job of summarizing the rising incidence of syphilis in a number of states, including California, Texas, Florida, New York, Ohio, and Indiana — even in rural areas. What (re)emerged in the gay community, largely affecting men who have sex with men (MSM), has now solidly moved into the heterosexual community.
Predictably, this has resulted in an increased number of cases of syphilis in pregnant women — and in cases of congenital syphilis. Although syphilis in adults is readily treatable with penicillin, congenital syphilis is a severe deformative disease, with a high frequency of blindness and deafness. Approximately 40% of affected infants die. Early detection in pregnancy is essential. The national congenital syphilis (CS) rate reached an all-time low in 2010-2012 with 8.4 cases per 100,000 live births. By 2014, the national rate had increased 38%, closely tracking with the national increase in syphilis cases in women. A few years ago, there were at most one or two annual cases of CS in the San Francisco Bay Area. In 2012, CS cases in California jumped to 35, and, in 2014, rose to 100 cases (2015 data are still being tabulated).
Specific counties within California have been more affected — Kern County identified 58 pregnant women with syphilis last year. Unfortunately, only 30 were treated prior to delivery, resulting in 28 cases of congenital syphilis. Six babies died. In Fresno County, where syphilis was almost non-existent six years ago, the “number of cases has been steadily, almost exponentially, increasing,” according to Ken Bird, MD, Fresno County’s Public Health Officer. Eighteen cases of CS were identified in 2014 and 40 cases of CS were identified in 2015. So many cases have occurred in Fresno that the county is now requiring all pregnant women to be screened three times during their pregnancy — during their initial prenatal screening visit, during the third trimester, and at delivery.
Many of these cases are occurring in immigrant and poor women, or drug users, with delays in seeking prenatal care. While all pregnant women in California are eligible for MediCal, many don’t know how to access care, resulting in delays in prenatal care and sexually transmitted disease (STD) screening, after permanent fetal damage has already occurred. In addition, public health facilities in these counties are overwhelmed with contact tracing, paperwork, and the difficult task of getting people back for three separate doses of intra-muscular penicillin, seven days apart. As one official said, people hear their diagnosis, and just disappear, too horrified to deal with the necessity of treatment.
Clinicians are being urged to screen for syphilis with the first prenatal visit. In addition to more aggressive contact tracing, public health authorities are being urged to prioritize female contacts of reproductive age. Maybe we should return to the days of mandatory syphilis screening when applying for a marriage license, and RPRs should be included with hepatitis and HIV as part of universal screening. I would recommend syphilis screening for anyone being screened for STDs, as well as those with an unexplained sore throat, tonsillitis, cervical or inguinal lymphadenopathy, or any kind of unexplained rash — regardless of their sexual history.
TB Quant Problematic in Leprosy; Trapping Flu Particles; An Old Scourge Revisited: Congenital Syphilis
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