Infectious Disease Updates - Zika Virus, Lyme Disease and the U.S. Influenza Season

Infectious Disease Updates - Zika Virus, Lyme Disease and the U.S. Influenza Season

Kalorama Information offers complete analysis of the global infectious disease diagnostics market with its recent titleThe World Market for Infectious Disease Diagnostic Tests. Previous posts in this blog reviewed infectious disease test market segments for hospital-acquired infections (HAIs); antimicrobial resistance;women’s health and sexually transmitted pathogens, hepatitis,HIV/AIDS,andrespiratory tract infectiontests.

Influenza in the United States

The United States is experiencing a relatively light flu season. The U.S. Centers for Disease Control and Prevention (CDC) tracks the number of patient visits for influenza-like illness (ILI) at a number of outpatient care facilities. The relative severity of the flu season - measured roughly from the fourth quarter through the first quarter of the subsequent year - can be determined from the average percentage of visits for ILI out of total visits. Outpatient visits for ILI also correlate roughly to rapid influenza diagnostic test (RIDT) demand.

In the fourth quarter of 2015 and first four weeks of 2016, the average percentage of U.S. outpatient visits was approximately 1.7% and 2.1% compared to 2.7% and 3.1% for Q4 2014 and Q1 2015; 2.0% and 2.7% during Q4 2013 and Q1 2014; 2.4% and 3.2% during Q4 2012 and Q1 2013; and 1.5% and 2.0% during Q4 2011 and Q1 2012.

Despite a current weak demand environment for RIDTs, leading vendors such as Alere and Quidel have been able to drive market growth by encouraging more routine testing to inform therapy and introducing new platforms. Quidel is converting manual RIDT customers to its Veritor Digital Immunoassay (DIA) reader system; Alere offers a CLIA-waived rapid molecular test for flu on the Alere i.

Zika Virus

The CDC has issued interim guidelines for the in vitro diagnosis of Zika virus infection in pregnant women, women of reproductive age, and infants. Few labs in the United States are able to perform Zika virus testing, including only 4 public health labs as of February 9, 2016.

During the acute stage of infection (within first 7 days of illness in adults or first two days after birth), RT-PCR testing for viral RNA can be performed to detect Zika virus. Acute stage infections can also be diagnosed using NS1 antigen ELISAs, though the assay is not widely available. Thereafter, dengue- and Zika-specific IgM antibody testing of serum should be used to detect infections from serum samples. Cross-reactivity of the IgM assays can result from infections of closely related flaviviruses that cause dengue, yellow fever, West Nile virus (WNV), Japanese encephalitis, and St. Louis encephalitis. Differentiation of cross-reactin IgM antibodies can be accomplished using plaque reduction neutralization tests (PRNT).

There are currently no available clinical test kits for the Zika virus. Test kit distribution can proceed following an emergency use authorization (EUA) for Zika virus diagnostics. The U.S. Food and Drug Administration (FDA) and CDC are currently developing such an authorization. Notable EUAs were previously issued for Ebola and pandemic flu test kits.

Companies able to serve the clinical market for Zika testing following the EUA could include GenArraytion, Vela Diagnostics, and Genekam Biotech. On January 27, Singapore-based Vela Diagnostics introduced the research use only (RUO) ZIKA Virus RT-PCR Test for surveillance. The company previously developed RT-PCR tests for chikungunya virus (CE-IVD) and dengue. Maryland-based GenArraytion launched its multiplex RT-PCR test for surveillance on January 29, 2016 as part of its MultiFLEX Bioassay panel that additionally targets dengue, yellow fever, and Chikungunya. Genekam Biotechnology in Germany released ready-to-use RUO RT-PCR kits on January 18.

The development of Zika virus diagnostics and vaccines has been hindered on some fronts by a lack of samples out of hardest-hit Brazil. Many international labs have resorted to using viruses from previous outbreaks that, while suitable for initial diagnostics development, are unable to cast light into potential viral mutations impacting virulence. Stalled sample sharing is a result of regulatory limbo in Brazil. A recently passed national law has yet to be implemented that aims to reform internationally led research and improve the sharing of benefits with Brazil of products developed from Brazilian biodiversity or genetic resources.

Lyme Disease

Researchers with the U.S. CDC, Mayo Clinic and health officials from several U.S. states announced the discovery of a new species of bacteria responsible for Lyme disease in North America. Critically, infection with Borrelia mayonii differs in its symptoms from more widely observed B. burgdorferi infections.  Common symptoms between the two pathogens include fever, headache and neck pain followed by arthritis. However, the newly discovered B. mayonii can also cause nausea, vomiting and diffuse rashes - rather than the tell-tale bulls-eye rash of B. burgdorferi infection.

Lyme disease has found rising attention from the clinical community as its endemic range has spread in Northern Europe and its incidence has risen in the United States over the past 20 years. Fortunately, B. mayonii can be detected using available immunoassay tests for Lyme disease. Follow-up molecular testing (PCR) can additionally differentiate the two pathogenic species. Diagnostics companies such as bioMérieux, Bio-Rad Laboratories, DiaSorin, Trinity Biotech, Viramed Biotech and Gold Standard Diagnostics serve the U.S. Lyme disease clinical immunodiagnostics market. T2 Biosystems and Canon BioMedical are also collaborating for the development of a non-amplified molecular Lyme disease test on the T2MR technology platform.