While I was scanning the New England Journal of Medicine (NEJM) last month, these photographs “caught my eye” (pun intended). But they reminded me of an important zoonotic disease. Do you know what it is ?
From NEJM (Apr 16, 2015): “A 33-year-old man who was a pig farmer presented with sudden blurred vision, pain, redness, and photophobia in both eyes. He had a 10-day history of persistent fever (temperature, 39.4 C°), malaise, and myalgia. Ophthalmologic examination revealed bilateral iridocyclitis (anterior uveitis). Laboratory testing revealed a γ-glutamyltransferase level of 129 U per liter (normal value), and a white-cell count of 11,700 per cubic millimeter (normal range, 4400 to 11,300). Clinical and laboratory findings suggested a diagnosis of leptospirosis. Serologic tests revealed IgM and IgG antibodies against Leptospira interrogans serovar serjoe.”
Leptospirosis is perhaps the most common zoonotic disease globally. It’s caused by Leptospira interrogans, a group of ubiquitous spirochetal bacteria that are capable of infecting most mammals (especially rodents, swine, cattle canids, and equids). Numerous populations are at highest risk (this oughta catch YOUR attention): famers, slaughter house workers, veterinarians, animal caretakers, fishermen, sewer and mine workers, military personnel and those engaged in outdoor freshwater activities (swimming, rafting, kayaking).
Incubation is 2-21 days (mean = 10 days). Clinical signs are generally non-descript: fever, chills, head and muscle aches, vomiting/diarrhea, +/- jaundice (known as phase 1 or bacteremic phase). Most cases resolve spontaneously, and thus are not or mis-diagnosed. Later during the “immune-mediated” or phase 2 (also known as Weil’s Disease) : hepatic and renal dysfunction / failure, pulmonic hemorrhage, and , perhaps ocular suffusion.
Because of it’s non-specific signs, symptoms, and lesions leptospirosis can be missed or go undiagnosed. From a One Health viewpoint, we must be aware and inform clients about the human risks when we make this diagnosis. Also, we should be constantly aware, as the “at risk” populations include nearly everyone in Mississippi at this time of year. Here’s a couple references:
NEJM article: http://www.nejm.org/doi/pdf/10.1056/NEJMicm1108425
CDC website http://www.cdc.gov/leptospirosis/pdf/fact-sheet.pdf
WHO web site, water-related diseases http://www.who.int/water_sanitation_health/diseases/leptospirosis/en/
Bharti AR , et al> Leptospirosis: a zoonotic disease of global importance. Lancet 3: 757-771, 2003. http://www.ncbi.nlm.nih.gov/pubmed/14652202