Computer programmers are associated with computer viruses, not human viruses. But at the end of April an Indian computer programmer landed in Boston incubating measles virus. He had been hired by a business investment firm whose offices were on the 18th floor of a Boston skyscraper, the John Hancock Tower. May 5 he developed fever, cough and then a rash and became the index case in what is so far an 11 person outbreak, the largest number of measles cases in the city since 1989. (Boston Globe) The outbreak is of special interest for what it says for the spread of infectious disease in the era of routine international travel.
Measles is rare in Boston, today, but for people of a certain age, measles was a common childhood event. I had it, and so did most every kid I knew when I was growing up. Its cause is a non-segmented, negative-sense RNA virus spread person to person via the respiratory route. It is a relatively simple virus, having only six structural proteins. Except for being non-segmented, it sounds eerily like the influenza virus. It has been known as an infectious disease since 1911, but the virus wasn't isolated until 1954, when Enders and Peebles succeeded in growing it in human and monkey kidney tissue cultures. They then adapted it to chicken embryo tissue culture, enabling the development of a vaccine (1963). Since then the disease almost disappeared in the US, but it remains a scourge in the developing world where it continues to sicken and kill children in prodigious quantities. In 2000 it was still the largest vaccine-preventable cause of childhood mortality, with an estimated 777,000 deaths worldwide, more than half in Africa.
When I was a child there were still some 500,000 reported cases a year in the US, although it is believed that most of the 4,000,000 children born each year at the time probably had measles in at least a mild form. About 500 of the reported cases died each year, 150,000 had respiratory complications (mainly pneumonia) and 100,000 had middle ear infections as a complication. There were 48,000 hospitalizations, 7000 seizure episodes and 4000 cases of encephalitis (data from Plotkin and Orenstein, Vaccines, 4th ed. p. 395). Measles is quite contagious, with a basic reproductive number (R0) of 12 to 18. R0 is the average number of new cases a single infected case would produce when introduced into a susceptible population. By contrast, the R0 for influenza is estimated at 1.5 to 3.5. Measles has an incubation period of 10 to 14 days (much longer than the 1 - 7 day range of influenza), but like flu it is contagious before symptoms appear. This means it is essentially impossible to prevent its spread once introduced into a susceptible population.
But most of the US population is not susceptible. The disappearance of this serious, indeed potentially fatal disease is due to almost universal childhood vaccination in the US (93% coverage). The vaccine contains a live virus and is often given in combination with mumps and rubella ("German measles", not related to this kind of measles). Some of the early vaccines were also combined with immunoglobulin to reduce the side effects and this may have reduced the vaccine's effectiveness in the early years. As with the recent outbreak of mumps in the midwest, we are now wondering how long the vaccine stays effective. We once thought protection was lifelong, and it may be for most persons. But some of the Boston cases had been vaccinated, so the question of whether booster shots are needed is again on the table.
Measles aside, the episode illustrates once again the ease with which an infectious disease can travel from one country to another, distant one. Within the last three years we've seen this happen with SARS, then mumps, now measles. While scientists are up in Alaska swabbing rectums in migratory birds for H5N1, most epidemiologists believe that if the virus becomes easily transmissible anywhere in the world, the most likely way for it to enter the US is on a human being, not a bird.
The arrival of measles in Boston, specialists said, illustrates the potential for dangerous germs to hitch a ride on a jetliner and travel from one corner of the world to another.
[snip]
"When we talk about globalization, it's not only globalization of goods and services; it's people and their history, including incubating diseases," said Dr. Gerald T. Keusch, a global health specialist at the Boston University School of Public Health.
"We can no longer think about putting up quarantines at the borders and expect that it's going to work for infectious disease any better than it works for the resourceful, determined people who come across as economic migrants," Keusch said. "We can't put up a shield." (Boston Globe)
The attention to wild birds is more related to the damage highly pathogenic avian (but not pandemic) influenza would do to the commercial poultry industry, not preventing entry of a pandemic virus into the US. There won't be a vaccine until months after a pandemic emerges and antivirals are in short supply and of questionable effectiveness. The way to prepare for a bird flu pandemic is the old fashioned way: rebuild and strengthen our public health and social services infrastructures, so badly damaged by years of neglect.
Planning now consists primarily in managing the consequences. Measles, mumps and SARS sketched out the picture. We shouldn't wait for it to be painted in full color to get ready.
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In a slightly related note:
http://www.abc.net.au/news/newsitems/200606/s1661185.htm
Hygiene better than drugs' in bird flu fight
Health professionals at a conference in Perth have been told anti-viral medication offers little protection against any future influenza pandemic.
At a bird flu seminar, doctors have been told too much emphasis is placed on drugs such as Tamiflu, and stringent hygiene routines offer better protection from viruses.
Infectious diseases expert Aileen Plant told the conference she has been surprised by the number of medical professionals she has seen ignoring infection control procedures.
I am not surprised by either comment; been saying both for a long time.
attack rate, Marissa: There are some interpretive issues here. Tamiflu isn't going to stop a pandemic. It should have some use for specific kinds of prophylaxis for certain groups, e.g., caregivers, family members of cases. It is of only marginal use in treatment.
Regarding hygiene measures, yes, it is true this is not the strong suit of docs. On the other hand, we don't really know how much hygiene measures do to interrupt disease transmission of influenza in general or H5N1 in particular. It is plausible they would have some effect and probably don't hurt (although culturing the soap bar in a bathroom is not a comforting experience I believe). However at this point this is a mantra.
The following could well have originated from Iran, Indonesia or indeed the global bureaucratic labyrinth, that is known as the WHO!
Journalists have no power to announce bird flu outbreak
... Agric Ministry cautions
From Emmanuel Akli, Takoradi | Posted: Monday, June 12, 2006
The Western Regional Director of the Ministry of Food and Agriculture, Mr. David Okine, has cautioned journalists not to rush into printing or broadcasting any suspected cases of bird flu in any part of the country.
He said journalist with the information of suspected bird flu should first report to either the district or regional director of veterinary services for investigation.
According to him, even if the district or regional veterinary officer's investigations proved that the reported case was indeed bird flu, he had no power to go public with his finding.
He would have to report it to his national secretariat in Accra, who would take samples to a designated laboratory in Accra for further investigation, and if it is confirmed the Director of Food and Agriculture would call a press conference to announce the occurrence of the avian influenza.
Quick actions would then be taken to stop the disease from spreading into other parts of the country.
Speaking at a workshop organized in Takoradi last Friday to educate the public on the disease, Mr. Okine said not even the minister of agriculture had the power to go public with the occurrence of the disease.
He noted that such stringent measures had been put in place because they did not want the media to cause unnecessary panic about the bird flu in the country.
The regional director of agriculture further told the gathering that it was the determination of the agric ministry to ensure that any information put in the public domain about the disease was nothing but the truth.
Okine noted that the poultry industry in Ghana nearly collapsed because of the way the media over-blew the bird flu issue, resulting in public boycott of poultry products though the disease had not even been reported in any part of the country.
He said the situation seemed to have changed due mainly to the massive public education campaign they embarked on.
He therefore called on the media to obey the laid down procedure and refrain from rushing into print or broadcast of the disease without first informing the relevant authorities.
He said a number of measures had been put in place to prevent the disease from spreading into the country.
According to him, tyres of all vehicles and cars entering Ghana from the neighbouring countries are sprayed with special chemicals in addition to special checks on the vehicles.
He revealed also that since migrating birds sometimes spread the disease, Nzema areas in the Western region had been put under special surveillance.
He explained that the migrating birds usually settled on wetlands that are common in the Nzema districts, and that the people had been well-educated about the disease and its symptoms.
Okine appealed to Ghanaians to always obtain movement permits from veterinary officers before moving animals from one geographical location in the country to the other.
He noted that this law had been in our statute books for a long time, but was not enforced.
The Western regional chairman of the Ghana Poultry Association, Mr. Tony Osei Mensah, on his part said the bird flu scare entered the country at the time poultry farmers had sold out their stocks because of the Christmas festivities.
He noted that most of the farmers were not prepared to invest in new stock because they were unsure if they would recoup their investment due to the boycott of poultry products.
He was therefore happy that the situation had now changed, with people now consuming poultry products.
According to him even if the disease should enter the country, it was the farmers who usually have contact with the birds, and who would be at risk; not the general public.
Mr. Mensah therefore appealed to journalists not to think they have gotten a scoop and rush to publicize any suspected case that might even prove wrong after laboratory investigations.
The workshop was attended by journalists, players in the poultry industry and the general public.
It was sponsored by the veterinary service directorate of the Ministry of Food and Agriculture, the Ghana Health Service, United State Agency for International Development (USAID) and Ghana Sustainable Change Project (GSCP).
Universal vaccination has fallen off for various reasons:
lawsuits, funding, and (my favorite) deliberately holding back because "other children are being vaccinated so mine doesn't need it".
GZH: How do lawsuits stop vaccinations? (a genuine question; could be. Didn't know it, though).
Re: lawsuites. [I am a retired attorny, btw] I believe GZH is referring to the fact that there were a lot of lawsuits that happened around reactions some people experienced to the swine flu vaccinations several decades ago. Therefore, the fear on the part of the manufacturers would be that they would be sued if people experienced similar adverse reactions to a new vaccine they had created.
It is not just the swine flu vaccine issue. There have been lawsuits brought against vaccine manufacturers for "adverse reactions" to other vaccines, e.g., the unproven link between MMR vaccine and autism and the unproven issue of thimerosol (mercury) toxicity. The anti-vaccine crowd is very vocal and influences legislators, not to mention parents.
Since vaccines are typically low profit, but high risk from a liability standpoint, I can understand why private companies are not that interested in making them. It is clear to me that the government should take over vaccine manufacturing and distribution.
Epifreek, not so sure having the govt manufacture and distribute vaccines which conjure up a sense of trust in most folks these days, especially given our current (US) govt's ongoing ineptitude and deceipt.
Er...make that "would conjure" not "which conjure." That one slipped right by my proofing - whoops!
Most large corporations provide some resources to the community gratis which they right off as "goodwill". The big pharmas are incredibly wealthy, perhaps they should consider vaccine production as their own "goodwill". Their bottom line will improve just because more of us are around to grow old.
The question of manufacturers being reluctant because of liability I know. What I was curious about is any evidence that lawsuits make people less likely to want to get vaccinated.
People would be put off by the news of the litigation, and especially by the publicity on thimoserol (a somewhat discredited mercury-based preservative in vaccines). Not that I wish to start THAT hullabalooh.