Hantaviruses – Bunyaviruses

00:01 So, because it is probably freshest in people's memories, we'll talk about the hantaviruses first.

00:08 So keeping in mind, again, inhalation of infected rodent urine or feces is the mechanism of exposure to this.

00:15 The mortality for these and perhaps why it is so fixed in our minds, the mortality is significant. It's at least half of the patients, up to 50%.

00:25 Hantavirus causes 2 very severe illnesses: pulmonary syndrome and hemorrhagic fever syndrome.

00:35 And why or how one patient gets one versus the other, probably has to do with their own susceptibility, but also, the tropism of the virus. Does it primarily affect pulmonary tissue, or does it primarily affect endothelial or vascular tissue? For hantavirus pulmonary syndrome, incubation is 1-3 weeks, but for hemorrhagic fever, it may be all the way up to 6 weeks, depending on viral load of the exposure.

01:03 Diagnosis with both can be PCR, but the further out one gets from primary infection, the less likely one is to find RNA which is detected by that PCR.

01:15 So, in hantavirus hemorrhagic fever, we look for a 4-fold rise in immunoglobulin G antibody, especially if one can do acute and convalescence serology testing.

01:26 Clinical manifestations are different, of course.

01:29 Hantavirus pulmonary syndromes starts with that flu-like illness, which we talked about, followed by a sudden onset of respiratory failure.

01:37 And we're not just talking a little shortness of breath, but feeling a bit like, "I can't catch my breath," and then rapidly evolving pulmonary edema.

01:45 The one patient that I've managed was a 19-year-old young man who acquired this from sweeping up a closet up in upstate Arizona, and he describes exactly that. One minute, he's feeling just a little flu-like, and the next minute he was gasping for breath.

02:01 It makes sense if there's a sudden release of pulmonary edema.

02:05 In hantavirus hemorrhagic fever, the flu-like illness is followed, then, by intense headaches, severe myalgias, especially back and abdominal pain, along with nausea. And then the patients a rapidly progressive -- experience a rapidly progressive low blood pressure with acute shock, vascular leakage, the hemorrhage that we talked about, and then not just acute kidney failure, but in fact, multi organ failure.

02:31 So, as you can imagine, at that process, similar to other hemorrhagic fever viruses that we've talked about in other sessions, Ebola virus, Lassa fever virus, the mortality can be really quite high.