Underlying Conditions: Swine Flu, Obesity, Pregnancy, Cytokine Storms, Ebola, Factory Farms and “The Frog and Peach”

7/23/2009

The swine flu genie, now officially out of the bottle as a WHO-certified global pandemic, has left a trail of mostly non-lethal misery (so far) stretching across 145-and-counting countries.

In the U.K., experts predict there could be as many as a 100,000 cases per day by August – which would also dash hopes for an economic recovery any time soon, according to a new study.

In Argentina, flat-footed bureaucrats are in the cross-hairs for taking too long to implement protective measures. Now Argentine pigs are sick, too.

In Saudi Arabia, where nary a pig dares wander, officials are bracing for millions of devout Muslims planning hajj trips this November, advising the old, young, pregnant and those with chronic conditions to reschedule.

In the U.S., a new survey suggests that obesity doubles the risk for serious flu complications. Exactly why this is so is a bit of mystery, but a mouse study may provide a clue. Fat mice produce elevated amounts of leptin, a hormone involved in immune response. Researchers theorize that the mice became desensitized to leptin, so their immune systems don’t kick into gear fast enough. When their immune systems finally do kick in, they go into overdrive with a “cytokine storm” – a defense so strong, it kills the host.

At the other end of the spectrum in the developing word are the nearly one billion chronically hungry weakened by malnutrition. Now factor in air pollution, which has long been known to exacerbate respiratory illnesses in general, and it is really not too much of stretch to say that almost everyone suffers from some kind of complicating underlying condition. To put it in medical terms, co-morbidities are probably the rule, not the exception.

Still, there is something particularly unfair and frightening about the risk to pregnant women. Though case numbers are small, a disturbing trend has begun to emerge of otherwise healthy women fighting for their lives and the lives of their unborn babies only days after coming down with swine flu.

The CDC’s page on “Pregnant Women and Novel Influenza A (H1N1) Virus: Considerations for Clinicians” does not discuss etiology, but it might be similar to the obesity story — although instead of leptin desensitizing the immune system, pregnancy itself might act as a dampener (to prevent rejection of the fetus). By the time the mother’s body mounts a defense, it is too much, too late.

Influenza presents another, more subtle, threat to the unborn: Exposure to the virus in the first trimester appears to increase the (still small) risk the child will develop schizophrenia later in life. Again, the “how” remains murky, but if it is due to the mother’s immune response rather than direct exposure to the virus, then a vaccine, which also triggers an immune response, could be dangerous.

As swine flu begins to spread into the developing where maternal health care is already spotty, the effects of this pandemic could prove especially heartbreaking.

PIGS, PATHOGENS & OPPORTUNITY

Now a second strain of a combo pig/human/avian influenza virus has been identified in Saskatchewan, Canada. So far it causes only mild illness and spreads pig-to-pig and pig-to-person. Whether it can spread person-to-person is still unknown; the illness may be so mild that patients aren’t tested. But it shows that such viral mixing is likely much more common than previously thought, and that large hog factory farms with their high density populations provide a perfect setting.

Meanwhile, on the other side of the world in the Philippines, pigs have been identified as a host of Reston ebolavirus, the only strain that isn’t fatal to humans. The discovery, via metagenomics, came as a surprise. (listen to Science magazine podcast with APHIS-USDA researcher Michael McIntosh). The pigs were also suffering from porcine reproductive and respiratory disease syndrome, the severity of which may have been the result of co-infection. USDA researchers are concerned, of course, about food production and safety implications. The WHO is worried about the ease of pig to human transmission. In January, several hog farm workers, along with a butcher, tested positive for REV antibodies. Should the strain mutate into a more virulent or even lethal version, all bets are off on stopping the carnage.

Eventually, the fog of the current battle against swine flu (a.k.a. “Pandemic H1N1 2009 “) will lift. One can only hope that then policy-makers will – finally – begin to shift focus to the biggest “underlying condition” of all: a modern farming system rife with significant public health dangers. Otherwise, almost inevitably, they will find themselves in a few years once again calling for emergency conferences, fretting over limited budgets, drawing up distribution plans for vaccines and resistance-prone anti-virals and fighting a variation of the very same war.

Perhaps Peter Cooke put it best in the cult classic “Frog & Peach” routine he performed with Dudley Moore about a catastrophic failure of a restaurant located in the middle of the Yorkshire Moors. When asked whether he had learned from his mistakes, Cook’s proud proprietor replies, “Yes! I have learned from my mistakes! And I am sure I could repeat them exactly!”

Well, exactly…