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By Angene Johnson
After a recent dinner at my uncle’s house in Virginia, I finally had a chance to look at the March edition of National Geographic on my train ride back to Foggy Bottom (Washington, DC). As I flipped through the front of the magazine towards this month’s cover article, on saving energy in homes, the “Environment” article caught my eye. Entitled “Mosquito Hosts,” the short piece describes one consequence of the currently tanking economy that I hadn’t previously considered.
Apparently, the recent increase in home foreclosures has resulted in a spike in the number of abandoned homes which is accompanied by, in warmer parts of the country, an increase in the number of abandoned swimming pools, hot tubs, and decorative ponds. Without being regularly cared for, these stagnant bodies of water turn into unsightly green pools of algae and, more importantly, potential breeding grounds for disease carrying mosquitoes.
The latest issue of the Economist highlights a new idea in malaria prevention. Traditional prevention efforts emphasize spraying, but mosquitoes evolve resistance to insecticides. Now, Penn State University’s Andrew Read offers this insight, which can help avoid the resistance problem:
To stop malaria, we only need to kill the old mosquitoes.
Once an adult female Anopheles mosquito feeds on a human already infected with malaria, it still takes 10-14 days for the parasite to mature and migrate to the mosquito’s salivary glands, at which point she can infect another human. Since most female Anopheles mosquitoes live only 1-2 weeks (with some surviving up to one month), many of them will die before becoming capable of transmitting malaria.
The Economist explains what the researchers studied and how their findings could be applied:
by revere, cross-posted from Effect Measure
When an Ebola virus related lab accident in German occurred, special pathogens researchers girded themselves for bad news. Working with agents for which there is currently no treatment of vaccine requires high containment laboratories, often touted as being virtually fail safe. While engineering and procedural controls can be instituted to minimize accidents, the wild card is always the human element, so accidents in these laboratories happen. There has already been an Ebola related death in such circumstances, and when the German woman pricked her finger with a needle containing Ebola virus, there was fear of another. While there is no vaccine for Ebola currently in use, several are in development, and one was tried on an emergency basis. The incubation period is now past and the lab worker remains healthy. Was it the vaccine that saved her would she not have developed Ebola in any event? Helen Branswell (Canadian Press) takes it from there:
by revere, cross-posted from Effect Measure
I’m just getting around to reading the Brief Report by Blachere et al., “Measurement of airborne influenza virus in a hospital emergency department” (Clinical Infectious Diseases 2009:48:483-440) but it’s quite interesting. We’ve noted fairly often here that we still don’t know for sure what the main modes of transmission of influenza are, something that surprises many people. We “know” that flu can be passed from person to person via the respiratory secretions from runny noses, coughs and sneezes but we often don’t think more deeply about this. We know that viral material can remain viable on inanimate surfaces like doorknobs and arm rests for long periods (maybe days), but we don’t know how often this kind of exposure results in actual infection. As for the virus passing through the air between people, we don’t know if this is through the rather large particles easily visible with coughs and sneezes, particles which are quite heavy and settle out quickly within a few feet or most of the source and aren’t breathed deep into the lungs; or much via the much smaller aerosols that can remain suspended in the air for long periods (perhaps days) and penetrate easily into the depths of the lungs. You can see immediately how the size of the droplets might make a difference. If you go into a hospital emergency room during flu season, are you only likely to get infected if you sit next to an actively shedding flu patient in the waiting room or is the air of the waiting room full of floating flu virus? The paper by Blachere et al. set out to measure the sizes of floating aerosols containing viral material in the air of a hospital emergency department at the height of the 2008 flu season (February).
In today’s New York Times, columnist Nicholas Kristof turns his attention to a problem that’s been worrying the public health community for the past several years: MRSA, or methicillin-resistant staphylococcus aureus. The bacteria’s antibiotic resistance makes it hard to fight, and it’s responsible for a growing toll of deaths over the past year – including several among otherwise healthy people.
Kristof focuses on Camden, Indiana, a small farm town where family doctor Tom Anderson recently became alarmed by the number of MRSA infections he was seeing:
by revere, cross-posted from Effect Measure
The scientific literature is full of specialized papers that on their face would seem to be of little interest. Here’s a title like that: “Prevalence and seasonality of influenza-like illness in children, Nicaragua, 2005-2007″ (Gordon et al., Emerging Infectious Diseases 2009 Mar). Over 4000 Nicaraguan children, aged 2 to 11 years old and living in the capital of Managua were followed for 2 years, April 2005 to April 2007 and observed for development of ILI (influenza-like illness). We know a lot about influenza in major industrialized countries in the northern and southern temperate zones, but very little about the epidemiology of seasonal influenza in tropical regions. Is the pattern of the disease in these populations the same as in temperate climes? Is there a lot of flu or just a low level? Is it still seasonal influenza? The US and Europe have recently set up surveillance systems that help answer these questions but most countries don’t have those resources.
by revere, cross-posted at Effect Measure
The peanut butter/peanut paste ingredient based salmonella outbreak has been in the news lately and we’ve discussed it here (and here, here, here, here, here). There are now about 500 reported cases and six deaths. That’s a case fatality ratio of just over 1%. So what if there were a disease outbreak of 100,000 cases with a case fatality ratio of 20%? I think we’d be pretty alarmed. But it happened in 2005. And it happened in 2006 and 2007 and last year, 2008 And it’s happening, now, too. It isn’t salmonella or or even HIV/AIDS, although it is estimated to kill more people in the US than both put together. It is methicillin-resistant Staphylococcus aureus (MRSA), the difficult to treat antibiotic resistant bacterial infection sometimes called a killer superbug. Originally associated with hospitals, MRSA has now moved into the community. It is a major medical and public health problem and there is still much we don’t know about it, like where it hangs out. Now, thanks to our Scibling blogger (Aetiology) Tara Smith and her colleagues, we know a good deal more. And what they found out is disconcerting.
I’ll let Tara give you the gist:
by revere, cross-posted at Effect Measure
Every parent’s or grandparent’s nightmare is to have their darling little one suddenly carried off by illness. Flu isn’t on the radar screen of most parents but in recent years the public health community is taking notice. The first alarm occurred in the bad flu season of 2003 – 2004 when a retrospective tally showed over 150 pediatric deaths associated with flu. That was more than half again as much as we thought were occurring, although data was not very good. So a new pediatric surveillance system was put in place. One of the things it is showing is that methicillin resistant Staphylococcus aureaus (MRSA) is a surprisingly common accomplice in pediatric flu deaths. An excellent summary by Maryn McKenna at CIDRAP News gives some of the details. McKenna is an authority on MRSA and knows a lot about flu, so her piece is well worth reading, as is her blog, Superbug, which focuses on MRSA.
Rachel Nugent at Global Health Policy reminds us that it’s World TB Day. She’s got good news and bad news about tuberculosis around the globe. On the plus side, tuberculosis control funding has reached an all-time high, and the number of TB cases per capita has dropped. On the minus side, the number of cases is increasing, and more and more of these cases are turning out to be resistant to many of the drugs generally used to fight them.
In today’s New York Times, Celia W. Dugger looks at the lives of South Africans with MDR and XDR TB (MDR is multi-drug-resistant, XDR extensively drug-resistant). Many of them are held in a hospital that’s essentially “a prison for the sick”:
Revere at Effect Measure addresses a troubling article, published in yesterday’s Atlanta Journal-Constitution, about the Centers for Disease Control and Prevention’s handling of the Andrew Speaker tuberculosis case. You might remember the case, because it got a lot of media attention. Speaker was the Atlanta lawyer who was thought to have XDR TB and boarded a plane to return home from Italy despite having been told not to by health authorities. CDC issued an isolation order for Speaker, and held a press conference about how he could’ve spread the disease aboard his international flight. It was later determined that Speaker had multi-drug-resistant (MDR TB) rather than the more-feared XDR form.
Now, Alison Young reports in the AJC, “The handling of the Speaker case was so unusual that it has raised questions among other TB experts, including whether CDC publicized Speaker’s case in a quest for more money.”
