epidemiology
revere | January 29, 2008Since the antiviral agent oseltamivir (Tamiflu) has been touted as the global savior should a bird flu pandemic materialize the idea has been haunted by the specter of Tamiflu resistance. What if H5N1 becomes resistant to the drug? Is all lost? Now it is being reported in the media that the European Centre for Disease Control and Prevention has found that the predominant circulating seasonal flu virus in Europe this year, H1N1, is showing an unexpectedly high rate of Tamiflu resistance (19/148 isolates tested). This is much more than what has been seen in the past and was from patients not…
revere | January 25, 2008You'd think finding that there were some bird flu infections that went undetected would be bad news but it is actually good news. Not tremendous good news but better than no news, and that's unusual in the bird flu world. For some time the absence of mild or inapparent infections has been worrying. It means that the current case fatality ratio of over 60% is the real CFR, not one based on just the most serious cases coming to the attention of the surveillance system. Now scientists gathered in Bangkok at one of the many gatherings of those studying the disease have heard some new data…
revere | January 18, 2008In 2005 the world's bird flu doctors got together and pooled their meager knowledge about the epidemiology and clinical features of this zoonotic disase that has so far infected 350 people and killed 217 of them (latest "official" figures via WHO). In March of 2007 they got together again in Turkey and the New England Journal of Medicine (January 17, 2008 issue) has just published a joint report summarizing their discussion. Helen Branswell sets the stage:
The article, a review of data compiled on human cases to date, answers some questions about how the virus affects people. But it also…
revere | January 9, 2008Every year "flu season" comes during which there is a marked uptick in influenza-like illnesses (ILIs) in the community. An ILI is defined to be cough or sore throat together with a fever of over 100 degrees F. (37.8 degrees C.) or self-reported fever and chills as well as no other obvious cause (e.g., strep throat). But are all ILIs influenza? No. They are ILIs. In the absence of lab work (and since most are thought to be of viral origin, only non-specific symptomatic and supportive therapy is recommended and no diagnostic lab work is usually done), an ILI could be from influenza virus or…
revere | January 5, 2008If you are reading this you didn't die in 2005. But 2,447,903 Americans did die (if you aren't an American the good news is you aren't at risk of being included in the American death numbers). These are preliminary numbers, just released by CDC and the seven significant figures is a bit of -- what? -- overkill? Doesn't seem like the right word for this, but it is unlikely this is exactly the right number of deaths. Surely someone wasn't counted.
In any event, CDC tells us this corresponds to an "estimated age-adjusted death rate" of 798.8 deaths per 100,000 US standard population. The "age-…
revere | December 31, 2007Everyone seems to have an opinion about whether bird flu will be the next terrible global pandemic. In current parlance "bird flu" means human infection with the highly pathogenic avian influenza/A subtype H5N1. There is no doubt that this is the 800 pound gorilla in the global health room at the moment, but not because it is more likely to become a pandemic (NB: pandemic by definition is a globally dispersed sudden increase in infection among humans; the same situation for animals is called a panzootic, and it is plausible to say we have an H5N1 panzootic for birds now). On the basis of…
revere | December 27, 2007Bird flu is still flu and one expects an uptick of cases during "flu season" which usually gets underway in earnest in December. So from that perspective it isn't a surprise that December has seen human fatalities from bird flu in six countries: Pakistan, China, Vietnam, Egypt, Burma and, of course, Indonesia. Once the Pakistani cases are officially confirmed and added to the December tally for this flu season it will make it the worst December yet, but we shouldn't read too much into this. Flu seasons are notoriously variable and the numbers bounce around a lot from year to year. But . . .…
revere | December 12, 2007The dramatic infectious agents like MRSA, Ebola and bird flu get the headlines but there are a lot of others out there, some of them capable of being just as nasty. Consider the new variant of adenovirus serotype 14, for example:
Infectious-disease expert David N. Gilbert was making rounds at the Providence Portland Medical Center in Oregon in April when he realized that an unusual number of patients, including young, vigorous adults, were being hit by a frightening pneumonia.
"What was so striking was to see patients who were otherwise healthy be just devastated," Gilbert said. Within a day…
revere | December 8, 2007Earlier in the week we discussed the unfortunate 24 year old man who died of bird flu in Nanking in Jiangsu province. He had had no known contact with sick poultry. Now the father has bird flu. Did the father get it from the son? Did both get it from the same source? Or two different sources? Those are the open questions at the moment as Chinese health authorities struggle to follow up the health status of the father's 69 suspected contacts:
"The patient, a 52-year-old male surnamed Lu from Nanjing in Jiangsu, is the father of the serious case of bird flu diagnosed on December 2," said the…
revere | December 4, 2007China has just registered its 26th known case of bird flu and its 17th death. I emphasize known, because in a country of over 1.3 billion that has not been able to eradicate this virus from its vast poultry population, it would seem the real number is probably quite a bit higher. But what I want to return to about this case is something I have discussed before regarding the Chinese cases (and pertains to most of the other reported cases as well), but is starkest for the Chinese reports. But first, the pertinent part of the case:
China's first human case of bird flu in six months shows that…
revere | October 23, 2007If you have or have had small children you may be all too familiar with earaches. When our kids were small we felt as if we were single-handedly supporting the amoxicillin makers. A major cause of middle ear infection is the organism Streptococcus pneumoniae (S. pneumoniae), which sometimes it invades other tissues and causes bacterial meningitis (not the kind that you read about killing healthy teenagers, but bad enough) and sometimes other body sites. It is also a cause of pneumonia in adults and was a common cause of secondary bacterial pneumonia in the 1918 flu. That was then. Now there…
revere | September 6, 2007Australia's severe flu season reminds us, in dramatic fashion, that "regular" (seasonal) influenza can still be a severe disease. It's not just the elderly, but children, too. What about children in the developing world? What would you find if you went into one of Bangladesh's urban slums? We now have some information, presented as a Letter to the Editor in CDC's journal, Emerging Infectious Diseases. Children under the age of 13 with fever and symptoms of an influenza-like illness (dengue fever was excluded) in 2001 were tested for acute infection via antibodies to H1N1 or H3N2 influenza,…
revere | August 31, 2007A couple of weeks ago CDC's peer reviewed journal, Emerging Infectious Diseases, published online an ahead-of-print paper by Yang et al., "Detecting Human-to-Human Transmission of Avian Influenza A (H5N1)." The paper has now been published in the journal and predictably, it made news. It's an interesting paper, but we think some people are going beyond what it says. First, the gist according to Reuters:
A mathematical analysis has confirmed that H5N1 avian influenza spread from person to person in Indonesia in April, U.S. researchers reported on Tuesday.
They said they had developed a tool to…
revere | August 24, 2007Pandemic influenza gets its share of headlines but there are other viruses out there that also are good tabloid fodder, most notably Ebola virus which causes Ebola hemorrhagic fever, whose gruesome effects were depicted in Richard Preston's book, The Hot Zone. Ebola has some close relatives in the filovirus family, among them Marburg virus. Like Ebola it can cause a gruesome demise. Marburg has cause several outbreaks in Africa, one of the largest in Angola at the end of 2004, early 2005 (see the Wikipedia article on Marburg for more details). One of the enduring mysteries is where the virus…
grrlscientist | August 22, 2007tags: researchblogging.org, Egyptian Rousette, Egyptian fruit bat, Rousettus aegyptiacus, Marburg hemorrhagic fever virus, Ebola hemorrhagic fever virus, Uganda, zoonoses, pathogen
Portrait of an Egyptian Rousette or Egyptian fruit bat, Rousettus aegyptiacus.
Image: Wikipedia
Like something out of a sci-fi novel, a man from Uganda died a horrible, bloody death from Marburg hemorrhagic fever this past July. As a result, scientists from the USA and the African nation of Gabon raced to the area to search for the source of this disease, and they may have finally discovered it. The team tested…
revere | August 17, 2007I'm not sure which is worse. Pandemic flu preparation which puts most of its eggs (pathogen-free, of course) in the vaccine basket or the one that plans to distribute the non-existent vaccine in a way that it misses the most needy and vulnerable. I guess it's obvious that if the first is bad, the second is very bad so it's worse, but it also a warning that other kinds of preparation may also be seriously flawed from the equity point of view. I know many of you don't care about these folks -- undocumented immigrants, substance users, the homeless, homebound elderly, and minorities. Many…
revere | July 31, 2007One reason Helen Branswell is such a good flu reporter is she has the best contacts. Of course this is a chicken-and-egg proposition, because she has the best contacts because she is the best flu reporter. She gets it right and she explains it the way it was told to her. [By the way, I am not on her payroll. In fact she is uncomfortable about being praised. But I don't do it for her sake. She doesn't need it anyway. My motive is to show other reporters what good flu reporting is and encourage them to do the same. And there are a number of other excellent reporters, which I try to acknowledge…
revere | July 23, 2007Bird flu isn't the only virus dangerous to humans that finds its primary home in birds. West Nile Virus (WNV) and other arbovirus infections do, too. WNV is now on the rise in California and seems worse than last year:
There were 18 new human cases of West Nile virus reported this week by the California Department of Public Health, double the number counted since the first case of the year was confirmed on June 20. That brings the state total to 27, and puts the California count slightly ahead of 2005, when the virus sickened 935 and killed 19. Last year, there were only 292 cases statewide…
revere | June 25, 2007For a long time I (and many others) were of the opinion that the reported deaths from H5N1 and the extraordinaraily high Case Fatality Ratio (CFR; proportion of all infections that end fatally) was an over estimate due to underascertainment of infections that were mild, inapparent or just undiagnosed because they weren't severe enough to come to the attention of the medical care system. The reason for thinking this was that this is the pattern for most other infectious diseasesk, even serious ones like TB and cholera. Most of the infections are asymptomatic or at least undiagnosed. It is…
revere | May 30, 2007It was only last week we posted about XDR-TB. Yesterday CDC warned passengers on two international flights -- Air France 385, Atlanta to Paris on May 12 and Czech Air 104, Prague to Canada on May 24 -- they may have been infected by another passenger who had Extensively Drug Resistant TB (XDR-TB). Reportedly authorities could not reveal which row the male passenger sat in as this would violate medical confidentiality laws (HIPAA). So anyone on the plane could think themselves at risk, although it was probably only those in the same row and several rows front and aft of the passenger who were…