Sunday, July 16, 2017

Samantha King, Squak Mountain Hantavirus Survivor Interviewed on KIRO-7

The only other survivor of this last year's Washington state hantavirus outbreak, Samantha King, from Issaquah, WA is interviewed by KIRO-7's Natasha Chen.

 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

A Sixth Hantavirus Case in WA in Last the Last Eight Months

...and again.

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

A Fourth Case in Western Washington, 2016-2017 Hantavirus Cluster

A fourth hantavirus case in Western Washington since fall, 2016 has been reported in Skagit county. Details are not yet available, but the patient is said to have survived and recovered. My best wishes go out to them for a full recovery.

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.)

– Mark@hantasite


King5 preliminary coverage

Kiro7 preliminary coverage

Saturday, May 6, 2017

Hantavirus Fatality in Tri-Cities Area

A young woman, Shannon Davis, 24 years old and a mother of three, has died from hantavirus in the Tri-Cities area of Eastern Washington. This was the fourth case of hantavirus in a five month span in Washington state and it brings the fatality rate back to 50%.

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.
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

No One Asks if You Rode in a Car

What have I got to do with this?
When patients present at ER and Urgent Care rooms with respiratory symptoms that resemble the flu – or hantavirus – they are supposed to be asked by healthcare providers if they have had contact with rodents in the previous month or so. If so, hantavirus is to be suspected, even if still highly improbable. If not, the small probability attributed to hantavirus becomes even smaller, and the quest for a diagnosis and treatment plan goes on.

But no one asks if you rode in a car, a truck, or a tractor cab. Virtually everyone does so, frequently, so what would be the point? 

If people are, as I've theorized in previous posts, contracting hantavirus by exposure in vehicle cabin air systems, this first line of hantavirus detection simply misses it. Even after diagnosis, many patients who have hantavirus report that they cannot recall having had any kind of contact with rodents.

Detection of hantavirus does not get much better from there.  

Hantavirus Pulmonary Syndrome is a Zebra

Sin 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.

Dr. Hudzik, Dr. SzkodzinskiProf. Polonski: "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?

Reportable Disease

Because of its severity and high morbidity, about 40%, hantavirus is classified as a reportable disease, the Centers for Disease Control (CDC) is to be notified when cases are diagnosed by local healthcare practitioners. I have been assured by a CDC scientist that this system catches all of the HPS cases, at least in Western Washington. But what if cases of hantavirus infection are simply missed in the first place? 

The number of cases of hantavirus pulmonary syndrome (HPS) that are reported in the CDC's final statistics comprise only those that made it through the gauntlet of being suspected or spotted in blood work, then tested for, and finally forced through the resistance that some care providers show to diagnosing this rare illness. 

This is not the same as the number of actual HPS cases. 

As I studied hantavirus I grew concerned that that exposure difference, automobile cabin air systems, may be causing HPS cases and also causing them to be misdiagnosed. It even seemed possible that there could be a significant number of them. Of course, if you die, or nearly die, a significant number is 1.

Urgent Care Presentation

From 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

Testing requires that the doctors apply for permission from the CDC, almost the only place in the country that performs such testing. They must apply by going through their county or state health departments. The Protocol for Specimen Submission can be found in the CDC website, here:

It includes information on how to obtain the specimen, and ship it in a refrigerated package, along with links to the two forms that are to be completed, and the phone number to call to notify them when you are ready to transmit the specimens after you've received permission, and the International Air Transit Authority regulations to meet for how you package the specimen, and so forth. 

All very helpful. And a lot of time-consuming paperwork. 

Of course, when the physician receives the test results it will be too late to make any changes to patient care. The HPS patient will be dead or recovering by then. Even if results were quicker, there is no specific treatment for hantavirus, aside from caution in administering fluids, which can trigger refractory pulmonary edema. Those fluids were probably already administered during a life-saving effort to stabilize plunging blood pressure a couple days previously.  

By the time that it is received, a positive detection of hantavirus antibodies does not really change patient care. It is also not practical to test every patient for hantavirus, with its extreme rarity the number of false positives might outnumber the true positives.

Signal to Noise Ratio

Even 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.


I 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.

 “Nucleotide sequence data from 5 antibody-positive rodents indicated that Sin Nombre virus (the major cause of hantavirus pulmonary syndrome [HPS] in the United States) is enzootic in the Mexican states of Nuevo León, San Luis Potosí, Tamaulipas, and Veracruz. However, HPS has not been reported from these states, which suggests that in northeastern Mexico, HPS has been confused with other rapidly progressive, life-threatening respiratory diseases."

"The results of this study indicate that SNV is widely distributed in northeastern Mexico. The geographic distribution of Deer mice (P. maniculatus) in Mexico includes 23 states (28), and ≈20 million persons lived in rural areas in this 23-state region in 2010 (32). Yet, to our knowledge, no cases of HPS have been reported from northeastern Mexico or elsewhere in Mexico."

We hypothesize that HPS caused by SNV in Mexico has been confused with other rapidly progressive, life- threatening respiratory diseases (e.g., plague, tularemia, pneumococcal pneumonia, influenza).”
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.
"Taken together, our preliminary results suggest that ARDS/ALI are likely under recognized conditions, particularly in critically ill patients requiring prolonged mechanical ventilation. Earlier studies have estimated the mortality due to ARDS/ALI at around 133,500 deaths per year in the United States6. Given the possible under recognition however, ARDS/ALI are conditions likely responsible for even more deaths in the population. Besides mortality, ARDS/ ALI also leads to large amounts of costly and often debilitating morbidity in surviving patients and their caregivers1,3,6. Outcomes studies have consistently found significant functional and neuropsychological derangements at both 1 year and 5 years post illness1,2,3. Perhaps better identification of ARDS/ALI in the first place may help to more efficiently allocate health care resources – in turn potentially preventing some of the typical long-term sequelae currently experienced by survivors and their caregivers.
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.

The aetiology of community-acquired pneumonia (CAP) has been studied in various regions and settings. While these studies differ considerably in patient populations, diagnostic methodology, and presence of confounders, one intriguing constant finding is the failure to detect a pathogen in ∼30–60% of cases 19. Among the factors which may explain this observation, ambulatory antimicrobial pretreatment is the most attractive. Accordingly, there is evidence from the literature that the majority of cases of unknown aetiology may be caused by Streptococcus pneumoniae, a pathogen which is easily missed after one single dose of antimicrobial treatment 1, 10. Conversely, the recognition of Legionella pneumophila and Chlamydia pneumoniae has taught that unrecognised pathogens may represent important causes of CAP.
My interview with Outbreak News and coverage of the cabin air system question.

* Note  These posts will use Hanta to specifically indicate the Sin Nombre strain of hantavirus. 

Wednesday, April 5, 2017

Elevated Threat from Hantavirus in Parts of Western Washington

Juvenile deer mouse. He must have been fearless or ill.
I took this with an iPhone at close range. 
Update to elevated hantavirus risk warning issued April, 5.  As of April 26, 2017, the invasion of Deer mice appears to be continuing. With the spring weather they are in their breeding season and are at least as much of a threat as they were during the period in which the three recent confirmed cases occurred. For this reason, The warning I'm extending the warning issued below until further updates. The risk will likely decline with dry, warm, summer weather, if we get that. 

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.
a higher abundance of deer mice shedding hantavirus particles at a greater than usual rate, combined with an increased rate of incursion into human environments, has produced an elevated risk of humans contracting hantavirus. 

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

Another Local Hantavirus Case?

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.

People in areas with big leaf maples trees that are experiencing an increase in deer mouse populations should take particular precautions to protect themselves from airborne mouse debris. 

People should check their cabin air filters in cars, trucks, and tractors. Wear a particle mask and gloves!

People should work to exclude all mice and trap others. Spray with disinfectant and dispose along with the trap.