Hornig

1.  Introduction

Mady Hornig is Associate Professor of Epidemiology and Director of Translational Research in the Center for Immunopathogenesis and Infectious Diseases at the Mailman School of Public Health. She is rumoured to have an autistic child but this has never been verified.

She came to the autism debate by way of her paper Neurotoxic Effects of Postnatal Thimerosal are Mouse Strain Dependent (2004) (see below for details) which is alleged to have led the UK government to remove thiomersal from vaccines in 2004.

Perhaps the most notorious comment to come from Hornig's work is the 'grooming to excess' feature of her mice work as reported by David Kirby in Evidence of Harm.

"...putting up a photo of two mice. He has groomed through the skull, and eventually destroys his partner, Hornig said. Every parent of an autistic kid in the room could be seen grimacing in dark recognition of such destructive behavior.(page 312)"

This behaviour was one of the first to arouse the suspicions of a few people that Horning had a tendency to exaggerate and distort her findings. The 'grooming to the point of death' behaviour was not reported in her paper (see below) and a growing number of people are puzzled to how such a behaviour can be attributed to autism. Further, these same people were very curious as to how mice were diagnosed as being autistic at all.

2.  Neurotoxic Effects of Postnatal Thimerosal are Mouse Strain Dependent

2.1  Abstract

The developing brain is uniquely susceptible to the neurotoxic hazard posed by mercurials. Host differences in maturation, metabolism, nutrition, sex, and autoimmunity influence outcomes. How population-based variability affects the safety of the ethylmercury-containing vaccine preservative, thimerosal, is unknown. Reported increases in the prevalence of autism, a highly heritable neuropsychiatric condition, are intensifying public focus on environmental exposures such as thimerosal. Immune profiles and family history in autism are frequently consistent with autoimmunity. We hypothesized that autoimmune propensity influences outcomes in mice following thimerosal challenges that mimic routine childhood immunizations. Autoimmune disease-sensitive SJL/J mice showed growth delay; reduced locomotion; exaggerated response to novelty; and densely packed, hyperchromic hippocampal neurons with altered glutamate receptors and transporters. Strains resistant to autoimmunity, C57BL/6J and BALB/cJ, were not susceptible. These findings implicate genetic influences and provide a model for investigating thimerosal-related neurotoxicity [1].

2.2  The Issues

Hornig et al, claim that:

1. The mice they used are a good model for autistic people
2. The 'vaccine' schedule they used successfully mimicks childhood immunization programs
3. That the outcomes from Auto-immune disease sensitive mice were consistent with autism
4. That this indicates a genetically influenced sensitivity to thimerosal in autistic people

They further infer that:

1. There is a reported increase in autism prevalence
2. That auto-immune disease is both indicated and highly common in autism

2.3  The Talking Points

The first issue that needs to be addressed is how mice - or any animal - can be considered a good model for an autistic person. Autism is diagnosed via behavioural observations in three key areas: communication, socialisation and imagination. Hornig et al consider it enough to speculate that autistic people have an increased risk of susceptability to auto-immune disorders (they cite five studies to back this up). This is a contentious argument for two reasons. Firstly, it is not clearly established that autistic people are any more susceptible to auto-immune disorders than any other person. Secondly, even if it is true, there is no indication such a susceptability is even common.

Autism Diva had this to say:

"They were looking at a few behavioral measurements. One was a curiosity measurement, and one was how much they ran around and explored. Also, there were measurements on how much 'stereotypical behavior' they engaged in. That would be a repetetive up-and-down or side-to-side movement. They called a side-to-side movement an 'XY plane stereotypy' and an up-and-down movement was called a 'Z plane stereotypy'. The mice that were later found to have changes in their brains are called 'SJL Thim mice'.

This is what the study says about them: Within strains, SJL Thim mice had fewer total episodes of XY and Z plane stereotypy behaviors, with significant main drug effects rearing counts in SJL Thim mice, without sex effect.

Regarding their coordination, ..no thimerosal-related differences were observed in rotarod performance between or within strains on accelerating rod (20 rpm). Scarcely evidence of ataxia as is seen in 'acrodynia'.

Autism is usually defined as having these distinguishing features:

1) problems with social interaction;

2) problems with communication; and

3) restricted, repetitive, and stereotyped behavior, interests, and activities.

Did Dr. Hornig and colleagues find these features in the 'SJL Thim" mice?'

No."

The second issue that needs to be addressed is the rate at which these mice were exposed to thimerosal. Blogger Prometheus, a chemist by trade, produced a technical de-construction of Hornig's replicated vaccine schedule and concluded (please note: it is highly recommended that you read Promethus' whole post in order to see the science behind his conclusions):

"So, the human experiences a maximum blood level of 1.63 (arbitrary units) and the mouse - since it is being dosed at a smaller fraction of its half-life - sees a maximum blood level of 2.61. In short, the mouse gets to a blood level 60% higher than the human."

"I found myself wondering, "Why didn't they use the 50th percentile (50% weigh more than this weight, 50% weigh less - sort of an 'average weight')?" I have no answer - but I have an idea. By using the 10th percentile, they were able to give the baby mice an even bigger dose of mercury."

After reviewing the numbers stated:

"So, by using the 10th percentile weights, the authors were able to give the mice about 15% more thimerosal. This goes nicely with the dosing schedule to significantly raise the dose the mice receive."

In essence, Prometheus discovered a planned process of severly overdosing of the mice which far exceeded the dosage levels humans ever recieved. Prometheus also expressed dissatisfaction with the funders of the paper:

"So, you might ask, who paid for this study? The UC Davis M.I.N.D. Institute and The Coalition for Safe Minds. To remind you, the Coalition for Safe Minds' mission statement is:Our mission is to end the health and personal devastations caused by the needless use of mercury in medicines. But I'm sure that didn't influence the outcome of the study.

The third issue that needs to be addressed is covered in Hornig et al's opening paragraph:

"The prevalence of ASDs is reported to be rising worldwide, an increase not fully explained by changes in awareness and diagnostic patterns."

Hornig cites 4 papers to illustrate this statement. Intriguingly she cites Fombonne and Chakrabarti which flat out states that the prevalence rate is high but stable. She also cites Blaxill's study of the California data - data which has been refuted numerous times.

In fact, there is no evidence that there has been an . A recent New Scientist article entitled The Autism Epidemic that Never Was illustrates scientific opinion:

"One team, however, is ahead of the game. Back in July 1998, Fombonne and Suniti Chakrabarti of the Child Development Centre in Stafford, UK, started screening every child born in a four-year window (1992 to 1995) who lived in a defined area of Staffordshire, 15,500 children in total. As a result, they established baseline figures for autistic spectrum disorders - about 62 per 10,000. Then they did it again, in exactly the same place and exactly the same way, this time with all the children born between 1996 and 1998. In June this year, they reported that the prevalence of autism was unchanged (American Journal of Psychiatry, vol 162, page 1133). This study suggests that epidemic concerns are unfounded, concludes Fombonne."

And:

"This view (that there are many children today diagnosed with autism who would not have been labelled as such in the past) is difficult to substantiate, but in 2001 a team led by Helen Heussler of Nottingham University, UK, had a crack. They re-examined the data from a 1970 survey of 13,135 British children. The original survey found just five autistic children, but using modern diagnostic criteria Heussler's team found a hidden hoard of 56. That's over a tenfold rise in numbers, which puts the California figures in perspective. Heussler and her colleagues concluded that estimates from the early 1970s may have seriously underestimated the prevalence."

3.  Attempts at Replication.

A paper published in 2007 entitled Low Level Neonatal Thimerosal Exposure: Further Evaluation of Altered Neurotoxic Potential in SJL Mice Download comprehensively refuted the Hornig study.

"Considered together the present results do not indicate pervasive developmental neurotoxicity following vaccine-level thimerosal injections in SJL mice, and provide little if any support for the hypothesis that thimerosal exposure contributes to the etiology of neurodevelopmental disorders."

There was considerable surprise about this paper, given that it was produced by MIND - an organisation that to many seems to exist not to research autism but to establish links between autism and vaccines - and written by people (such as Pessah) who are believers in the autism/vaccine hypotheses.

4.  Blog Resources

• Rain Mouse?
• Tingling Mouse Tale
• Did I hear gold salts cure autism?
• Fools - Gold: Redux
• Nightmare at Columbia U: Return of Rain Mouse

5.  Also See

Thimerosal | Burbacher | Deth