10 October 2018 Blog Post: Endemic Typhus (not Typhoid!), The Norweigan Rat, Fleas and Pasadena: What Do These Four Things Have in Common?

You may have read press reports of an outbreak of typhus occurring in downtown Los Angeles and, on Friday, heard that Pasadena reported epidemic levels of flea borne typhus. So what is happening? And how are the four things in today’s post title related?
When discussing typhus and typhus fever, scientific vocabulary gets confusing and, frankly, somewhat unhelpful. Typhus or typhus fever is actually a group of bacterial infectious diseases spread by lice (referred to as epidemic typhus), fleas (murine or endemic typhus) or chiggers (scrub typhus). Currently, in Los Angeles we are experiencing an unusually high activity (i.e. an epidemic) of flea borne (endemic) typhus. So an epidemic of endemic typhus.
Confused yet? Wait, there’s more…
If you are thinking Typhoid Mary, stop! Typhoid Mary who was twice quarantined by the New York City Health Department (1907 and 1915 – the second time until her death in 1938) for spreading a communicable illness. While this is interesting historically,her story is unrelated to what is occurring in downtown Los Angeles and Pasedena. She spread typhoid fever due to Salmonella typhi and poor hand hygeine. In Los Angeles and Pasadena, we are experiencing typhus fever (due to Rickettsia typhi or Rickettsia felis) spread by fleas.
Even more confused? Understandably so… Let’s clear that up.
Between July and September of this year, Los Angeles County Health Department has identified nine cases of flea-borne typhus associated with downtown Los Angeles, and six of those cases were in people experiencing homelessness. Additionally, this year, 20 Pasadena residents have been confirmed to have typhus fever, up from the expected one to five cases per year (this makes the illness at epidemic levels as it is above the usual expected number and is a sudden jump). As of Monday, there have been a total of 57 cases of flea-borne typhus in Los Angeles County.
So where are people getting exposed? In Los Angeles County, the primary animals known to carry infected fleas include the Norweigan rat (see, that’s where they come in), feral cats, and opossums. People with significant exposure to these animals are at risk of acquiring flea-borne typhus. Pet dogs and cats that are allowed outside may also come in contact with infected fleas and could carry them back inside to you. Infected animals are not known to get sick from flea-borne typhus. You can refer to the Los Angeles County Health Department’s publication for more details on murine typhus and transmission patterns (as well as a really cool picture of a snarling opossum):
And what should I look out for? Flea-borne typhus may be a mild, illness, or can present as severe disease requiring hospitalization. Symptoms occur 7 to 14 days after exposure, and typically include abrupt onset of fever, headache, chills, muscle aches, abdominal pain, or vomiting. Fortunately this infection is easily and effectively treated with a course of antibiotics.
There are also several steps to take to reduce your exposure. These can include: storing trash in secure bins to avoid attracting animals, discouraging animals from nesting around your home by closing up crawl spaces, avoiding petting or feeding stray animals, using flea control products for domestic pets and using insect repellents on yourself when outside.
Hopefully this helps clear up any confusion. If you have any questions or are concerned with possible exposure or symptoms, please do make an appointment with us Santa Monica Primary Care by calling 310.828.4411.
As for myself, I’m going home and giving my dog a bath.

𝗦𝗶𝗴𝗻 𝗨𝗽 𝗳𝗼𝗿 𝗢𝘂𝗿 𝗡𝗲𝘄𝘀𝗹𝗲𝘁𝘁𝗲𝗿

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