An outbreak of Salmonella serotype Saintpaul has sickened 943 people since April. Nearly 14% of these cases required hospitalization. It has been hypothesized that tomatoes have been the vehicle for this food-borne infection. Here in Palo Alto, certain types of tomatoes (e.g., Roma and beefsteak) were taken off store shelves for a while. The latest report from CDC suggests that tomatoes may not, in fact, be the culprit. CDC epidemiologists are expanding their investigations to include food items that are "commonly consumed with tomatoes."
Epidemiological evidence indicates that while people of just about any age can contract the infection (age range of cases is <1-99 years), the most likely age group to contract the infection are 20-29 year-olds. The least likely age classes are 10-19 year-olds and people over 80. What food do young adults commonly eat with raw tomatoes that is less commonly eaten by the young or very old? I'd say salad greens but if that were the case, I'd expect a sex bias in infections. 50% of the infections are women and my informed guess (based on my experience with largely middle-class college students) is that 20-29 year-old women eat more salad than 20-29 year-old men.
So what is it if it's not tomatoes? Something having to do with consumption of alcohol? Some salsa ingredient like jalapeños or scallions? (note: another thing consumed in bars)
A piece in today's New York Times notes that the existence of $10 bed nets makes charity for malaria easy, cool, and almost addictive. Our kids' school ran a Nothing But Nets fundraiser this spring. I had the privilege of giving a lecture to a couple hundred very sharp elementary school kids about what malaria is, how you get it, and what we can do to eradicate it.
Classrooms competed to see which could raise the most money and, this being Palo Alto, I think there was a lot of money raised. I also had the amazing experience of clandestinely watching my own son open up his piggy bank one morning before school, pull out his own money (and there's not a whole lot of it in there), and decide to contribute his own $10 in addition to the $100 we had already given his class. You could see the reasoning being played out on his face: "If I give this $10 bill, I can help save the lives of a family of four. That's more important than a new Wii game." I was very very proud, to say the least. Providing kids with the opportunity to do good and feel like they are making a difference can lead to some incredible behavior. Maybe, just maybe, there's hope for us still.
I don't want to jump to conclusions about global warming, but the extremely early start to the 2008 West Nile Virus season in the Western United States is extremely troubling. Earlier this week, a Maricopa County, Arizona man became the first human case of WNV this year. The report of a WNV infected bird this week in Bakersfield, California means that WNV has appeared 2 months earlier than last year in Kern County, a place that saw 140 human cases and 4 deaths last year. There are a number of possible ecological explanations for why WNV activity could be off to such an early start this year. One set of possibilities involve warming temperatures. There is real concern that global warming will expand the range of a variety of vector-borne diseases. Let's hope that dengue and malaria don't manage to invade California too.
Screwworm myiasis, a disease in which blowflies lay their eggs around wounds or mucous membranes of mammalian (including human) hosts and the developing maggots eat the flesh of their living host, has recently emerged in Yemen. First reports in Yemen come from December 2007. The screwworm larvae are very sensitive to cold temperatures so one wonders if this emergence may be related to global warming. The disease used to be endemic in the southern United States but was eliminated some time ago. If the emergence of this infection on the Arabian Peninsula is indeed related to changing (probably nighttime) temperatures, then one also has to wonder about the possibility for re-emergence in North America...
There is a troubling outbreak of yellow fever currently affecting a number of South American countries, including Brazil and Paraguay. Yellow fever is a multi-host infection that can be transmitted between monkeys and humans. It is almost always fatal for species in the genera Alouatta and Ateles (howler and spider monkeys respectively). The Wildlife Conservation Society (WCS) has taken note of the real conservation concerns that arise for small populations of these monkeys in the context of the continuing yellow fever outbreak. In a world of increasingly fragmented local wildlife populations, where human-wildlife contact increases from human intrusion of forests and other ecosystems, control multi-host epidemics is likely to become an integral part of the conservation ecologist's portfolio.
The New York Times reported the largest recall of ground beef ever (143 million pounds) this week. The recall happened because a California slaughterhouse was caught using downer cows. According to the article:
Of the 143 million pounds that were recalled, 37 million went to make hamburgers, chili and tacos for school lunches and other federal nutrition programs, officials said.
Makes you feel good about these public programs, no?
notes on human ecology, population, and infectious disease
