Sunday, July 16, 2017
Samantha has displayed some really awesome toughness in coming back from this devastating illness. Many thanks to her for consenting to this interview and informing people about hanta.
A study at Vanderbilt University is investigating the antibodies, etc. in the blood of hantavirus survivors, and Samantha is participating in that study.
Friday, July 7, 2017
I regret to post that yet another hantavirus case, a fatality, has occurred in Washington state. The victim in Spokane, WA, was a man in his 50's and was believed to have been contracted hantavirus in Adams county, the first such case on record.
This brings the 2016 – 2017 Washington state hantavirus toll to six cases since November, 2016 (my wife), only an eight month span of time. The mortality rate is now back up to 50%, which is an indication that contrary to what has recently been claimed by health authorities, care procedures for hantavirus patients have not improved in any statistically significant way since the very early days after the Sin Nombre hantavirus was first recognized in 1993. (The first recognized hantavirus cases were usually fatal. When supportive care was implemented, the mortality rate dropped to around 40% where it remains.)
This has to be regarded as at least a small outbreak, not just a cluster of cases. This state is averaging a new hantavirus case every 40 days.
The surge in deer mouse population that occurred last fall is likely to have been accompanied by a surge in the incidence of hantavirus among that mouse population. If the hantavirus is more common among deer mice, this state may have gone through a long-lasting increase in risk of contracting this often deadly disease.
Saturday, July 1, 2017
Skagit county includes extensive terrain that resembles the foothills, big leaf maple tree mixed forest regions that characterized all three of the previous hantavirus infections in Western Washington since last November, 2016.
I will attempt to confirm whether, as I predict, there are big leaf maple trees in the immediate vicinity of the home of this fourth hantavirus victim. If so, confirmation of that prediction substantially advances the linkage between these cases and a deer mouse population explosion resulting from a "bumper crop" of big leaf maple seeds in summer, 2016, which provided an essentially limitless food source.
(This makes five hantavirus cases total in Washington, including the case in Eastern WA.)
King5 preliminary coverage
Kiro7 preliminary coverage
Saturday, May 6, 2017
Details are not yet available, but this reinforces the evidence for an increased risk for hantavirus exposure this year. Year-by-year spikes in numbers of cases are common, even on a national basis, for reasons both known, and unknown.
More can be learned in this piece in Outbreak News. http://outbreaknewstoday.com/hantavirus-washington-reports-4th-case-six-months-68684/
This post will be updated as information about the local ecosystem in that area of Franklin county are obtained.
My deepest condolences to Shannon Davis' family and loved ones.
Monday, May 1, 2017
|What have I got to do with this?|
Hantavirus Pulmonary Syndrome is a ZebraSin Nombre hantavirus infection is thought to be extremely rare in humans. Only about 700 cases have been documented. That makes hantavirus a zebra disease.
Zebras are also rare compared to horses. Unless you happen to be on the Serengeti plains.
When doctors are diagnosing a difficult illness, they are trained to have a rule-of-thumb in the back of their minds. "When you hear hoof beats, don't look for zebras." The odds that your particular patient will turn out to have an extremely rare, "zebra" of an illness, are very low. So don't even look for them, keep your eyes peeled for horses or you will waste valuable time and delay the patient's diagnosis.
But there can be a problem with that. If you don't look for something, you have a reduced chance of finding it. When a disease is a zebra disease, it tends to be misdiagnosed, or missed entirely.
, : "During medical training, students and residents are being taught a quintessential maxim of clinical medicine—“When you hear hoofbeats, think of horses, not zebras”. Common diseases are what physicians should expect to encounter. Unfortunately, in a world of horses, the hoofbeats of zebras too often go unrecognized or misdiagnosed."
Could hantavirus pulmonary syndrome (HPS) be being misdiagnosed, because it is a rare, zebra of a disease that few practitioners have ever encountered? What measures are in place to capture HPS cases?
Urgent Care PresentationFrom the Centers for Disease Control's page on hantavirus pulmonary syndrome, the primary source of guidance on HPS for Emergency and Urgent Care rooms around the country:
"The earlier the patient is brought in to intensive care, the better. If a patient is experiencing full distress, it is less likely the treatment will be effective.
Therefore, if you have been around rodents and have symptoms of fever, deep muscle aches, and severe shortness of breath, see your doctor immediately. Be sure to tell your doctor that you have been around rodents—this will alert your physician to look closely for any rodent-carried disease, such as HPS."
According to this guidance, it is incumbent on the patient, the seriously ill person that may be collapsing into hantavirus pulmonary syndrome, to inform the physician that they have had contact with rodents, probably, some time between seven days and seven weeks previously.
For this measure to work, there has to be extensive public outreach to inform potential patients, which could include almost anyone. Those people have to recall that outreach warning while they are seriously ill (or be fortunate enough to have a friend or family member know that you swept the garage) and you have to think to tell the doctor about it.
Hantavirus infection should also be suspected if a particular combination of blood test results is obtained. The combination is called a tetrad of symptoms because there are four changes that, together, suggest hantavirus infection. If that tetrad is spotted in the blood count test tests by someone knowledgeable enough to look for it, hantavirus should be suspected. The patient would then likely be tested for antibodies.
Even in the modern, excellent medical facility where my wife recovered, none of our doctors, nurses, or techs had ever encountered hantavirus before as is likely the case with most Hanta patients. It was almost literally the last thing anyone thought of or discussed during a week of brain-wracking over what was going wrong. They did not know what was wrong, so, they treated for everything they could, and provided supportive care. That was the right treatment, (fortunately!) but it does not hinge on, nor support, the diagnosis of hantavirus.
Diagnosis of hantavirus requires testing for antibodies to it, and that is not a trivial thing.
Hantavirus Antibody Testing
Signal to Noise RatioEven if you aren't expecting a zebra, if one walks up and presents itself, it would be hard to miss. Right?
What if that zebra was engulfed in teaming throngs of horses, gazelles, and zebu? What if HPS resembled other diseases that were far more common? When something could be lost in a cloud of similar things, you have to think about something called signal to noise ratio, (S/N).
|Just one of the gang.|
HPS patients present with symptoms that resemble a variety of other diseases, syndromes and categories of illness. Influenza, or flu-like illness, is a common early diagnosis. Community acquired pneumonia (CAP), a category, is the catch-all term for respiratory problems that the hospital didn't transmit. CAP can be caused by numerous pathogens, viral and bacterial. Identification of the particular pathogen in a patient is unusual.
Community acquired pneumonia becomes a catch-all term that is applied when a patient presents with impaired breathing from what is often an undetermined agent or insult to their system. Community acquired pneumonia strikes somewhere between four and five million people in the U.S. per year.
HPS is one of many "insults" to the system that can cause what is called Acute Respiratory Distress Syndrome, (ARDS), a relatively new and still controversial classification of sudden respiratory collapse that may result from any of a variety of "insults" to the patient. These collapses follow a general pattern, and have a mortality rate of about 40%, about the same as HPS. Somewhere between 50,000 and 100,000 people per year are struck by ARDS in the U.S.
The huge range in these numbers reflects widely varying estimates of the number of severe illnesses and deaths that fall into this syndrome. A study of post mortem victims of respiratory collapse found that about half of all patients that met the criteria for ARDS were not diagnosed as having had ARDS while they were alive. That's a matter of multiple, somewhat different definitions and criteria.
|Zebra herd on the Serengeti plain.|
From National Geographic
Differentiating ARDS caused by hantavirus from ARDS caused by requires some means of differentiation. Unfortunately, there are only general reasons for guidance. Hantavirus can be ruled out for cases of ARDS that have a clear source, such as a recent surgery or other illness. But hantavirus is only suggested as a faint possibility in cases with known exposure to rodents, and patients often have no way of knowing that they had that exposure, some weeks previously.
Misdiagnosis of hantavirus was recently reported in a case in Brazil, where the HPS syndrome is a newly identified condition. Hantavirus misdiagnosed as Dengue In places where the medical community is not trained to look for hanta, it tends to get missed. A kind of "latching" effect may appear in the statistics for this reason, with states reporting hantavirus enough to get press coverage tending to find more of it afterward.
ConclusionI can't be certain that people have been contracting hantavirus through infestations of their cabin air systems, but neither can anyone be assured that they are not.
There are reasons to believe that significant numbers of cases of hantavirus go undiagnosed in both Mexico and the United States.
Effort should be undertaken to better determine the scope of undiagnosed hantavirus from any source, and the particular question of whether vehicle cabin air systems are a mode of infection that has slipped "under the radar" of hantavirus detection.
Some comments on related webpages and excerpts from related references
The CDC webpage on hantavirus transmission makes no mention of vehicles, let alone of vehicle cabin air system infestations.
The King County Public Health site now has a pretty good update on hantavirus posted here:
This advisory is mainly directed at health care providers. It now specifically calls out vehicle cabin air systems as suspected transmission mechanisms. These changes probably would have never happened if it were not for this website calling attention to these issues.
Unfortunately, the general hantavirus information page and the Health Insider article make no mention of checking cabin air filters for deer mouse infestation. It does not mention that this common site of Deer mouse infestation even exists.
This needs to be changed, and the information for health care providers needs to be disseminated on a national basis. It would also be reasonable to develop some form of instruction that for patients presenting with symptoms resembling hantavirus, someone with proper ventilator mask and gloves should check the cabin air filters of vehicles they have used for signs of rodent infestation.
|Hantavirus cases by state of reporting from CDC. Note that many states|
have never reported hantavirus, even though they have plenty of mice.
Same with three northernmost states of Mexico, as described above.
Before making any firm conclusions however, it should be noted that although the results of our preliminary study are suggestive of under recognition of ARDS/ALI, they are subject to a number of important limitations."
The incidence of ARDS in Maryland is in the range of 10-14 cases per 100,000 people. The ARDS mortality rate is 36% to 52%, similar to that calculated in previous studies.
* Note These posts will use Hanta to specifically indicate the Sin Nombre strain of hantavirus.
Wednesday, April 5, 2017
|Juvenile deer mouse. He must have been fearless or ill.|
I took this with an iPhone at close range.
A cluster of sin nombre hantavirus cases comprising at least three people has occurred in Western Washington. This, combined with observations of the local environments of these patients, makes it possible and appropriate to warn of an elevated risk of contracting hantavirus in similar areas for the near future. This warning is intended to have greater specificity than those issued by local health authorities.
Observations have confirmed that all three of these recent hantavirus patients, along with an earlier (1999) case near Monroe, lived in areas with significant populations of big leaf maple trees. These trees have recently produced very large crops of maple seeds that are a favored food for deer mice, the local reservoir species for hantavirus. This has resulted in what appears to be greater abundance of deer mice in the area.
In general, a higher population of deer mice leads to a higher portion of the deer mice contracting hantavirus, and to more of them shedding hantavirus particles in their urine and feces.
This means that it is likely that there are both a greater number of deer mice, and that they shedding a greater amount of hantavirus than is usually the case.
In addition, heavy rainfall in Western Washington has placed these deer mice under environmental stress, their food sources are now depleted and rotting and their underground burrows are often flooded. As a result, there exists an increase in the number of deer mouse intrusions into human homes, vehicles, outbuildings, garages, and vehicle cabin air handling systems.
It is probable that: In areas where big leaf maple trees grow, which includes much of the Western Washington lowland forest region, from the foothills of the Cascades to near coastal areas,
|Big leaf maples trees with massive seed clusters.|
Fall, 2016. The leaves are 10" to 12" across.
If your property has big leaf maple trees, or adjoins areas that do, you should take particular care to avoid breathing in dust from mouse debris. This includes extra caution cleaning garages, outbuildings, vehicles, and other areas where these extremely common mice have intruded.
Areas without these trees may also see an increased risk because of ground water saturation driving mice from burrows and rodent spillover from adjacent areas.
The cabin air handling system in a vehicle is suspected in one of these local cases. The filters in these systems in automobiles, trucks, and tractors that have been parked in areas with big leaf maple trees should be inspected for rodent infestation and replaced as needed. Inspection should take place while wearing respirator mask and gloves.
I posted a more detailed analysis of this threat weeks ago, before the third recent local case was reported. Some of the qualifying words could be adjusted, but most of this discussion from March 17 is still correct.
For detailed directions for cleaning up deer mouse debris, look here for a CDC brochure.
The following segment from KIRO–7 news in Seattle gives an excellent summary of current developments. KIRO–7 3rd Hantavirus Case
Tuesday, April 4, 2017
Unfortunately, there are now reports of another probable case of hantavirus in the the Cascade foothills of the Puget Sound area. A woman from Issaquah, living near the Squak Mountain area, where the recent fatality lived has been hospitalized with what is believed to be the disease.
My deepest hopes for recovery go out to her and her family and loved ones.
Also unfortunately, it appears that the local health authorities continue to believe it their duty to minimize, allay concerns, and generally downplay the very real and current threat of hantavirus.
I spoke with Jeff Duchin, the King County Health Commissioner a week or so ago about this elevated threat. I described, in detail, the increase in deer mouse population that was being seen in the area.
His response was, "We'll just have to wait and see," about whether the the two known hantavirus cases raised concerns. Now we have a third case, and, quoted in the King5 article, "Health officials do not believe the two cases are connected but say there are reports of more deer mice in the area."
Three cases, at least, in rapid sequence after 13 years without a single case is a hantavirus cluster.
On at least a small scale, it is a hantavirus outbreak.