How are sadness and happiness like diseases? They're infectious, study finds

Is sadness a sickness? It appears to spread like one, a new study has found.

Researchers at Harvard University and MIT wanted to see if a mathematical model developed to track and predict the spread of infectious diseases such as SARS and foot-and-mouth disease could also apply to the spread of happiness -- and found that it worked. 

They used data collected from 1,880 subjects in the Framingham Heart Study, a long-term research effort that has followed subjects since 1948 (and added some new ones along the way), giving them physical and emotional exams every two years. At each visit, subjects were classified as content, discontent or neutral. The researchers monitored how these emotional states changed over time and how these changes depended on the emotions of the people with whom the participants came into contact.

When the information was put into a traditional infectious-disease simulation, slightly modified to reflect the unique qualities of emotional spread rather than actual disease, the researchers found a correlation between an individual's emotional state and those of the person's contacts.

In other words, it appears that you can catch happiness. Or sadness. Moreover, the "recovery time" doesn't depend on your contacts at all, which is a hallmark of diseases but surprising in an emotional context, since continuing contact with happy or sad people could be expected to affect one's emotional state even after the initial "infection."

People were found to "recover" (return to neutral) more quickly from discontent than from content; on average, a contentedness "infection" sticks around for 10 years, but it takes only five years to recover from discontent. While this may still seem like a long time, the work focused on long-term emotional states because they are more accurate measures of general life satisfaction than fleeting moods, which are already known to be contagious (think laughter).

On the other hand, sadness is more contagious than happiness: A single discontent contact doubles one's chances of becoming unhappy, while a happy contact increases the probability of becoming content by only 11%.

Researchers also found one way that emotions act differently than diseases -- they can arise due to events in your own life, such as a promotion or a disease diagnosis, rather than solely being "contagious." In another win for the good guys, it appears that happiness is more likely to come about spontaneously than is sadness.

A report of the emotions-as-diseases research has been published in the Proceedings of the Royal Society B.

-- Rachel Bernstein

Photo: We may recover from sadness more quickly than we do from happiness, but it appears to be more infectious. Credit: Reuters

Add breast-feeding to the protect-a-newborn checklist. (One Kardashian has)

Newborns need adults to protect them not just from obvious risks such as car accidents, falls and well-meaning toddlers who want to carry the baby, but also less obvious risks, such as infections. That amounts to more than simply a washing of hands. Everyone might not know this, but Kourtney Kardashian? Well, she might. (More on that later.)

A study published Monday in the journal Pediatrics parses the data on more than 4,000 infants and their risk of infections.

The researchers, based in the Netherlands, write in their conclusion:

"Exclusive breastfeeding until the age of 4 months followed by partial breastfeeding was associated with a significant reduction of respiratory and gastrointestinal infectious diseases in infants. Exclusive breastfeeding until the age of 6 months tended to be more protective than exclusive breastfeeding until the age of 4 months and partially thereafter."

That is, the researchers couldn't say for sure that 6 months is better, but they're pretty sure it is. The results aren't especially surprising but rather more of an effort to gain data on the benefits of breast-feeding. And you know how we love data ...

The researchers recommend policies that encourage exclusive breast-feeding for at least four months. They're pretty sure six months would be better. 

Here's the breast-feeding study; a guide to breast-feeding, courtesy of the U.S. Department of Health and Human Services; and an explanation of the Kardashian sister reference.

Apparently, the sisters are famous, and thus people pay attention to them: The Kardashian phenomenon. So, having a baby? Note Kourtney's position; Kim's stance is still a little unclear.

— Tami Dennis

Photo: A mother lends some extra protection. Credit: Ricardo DeAratanha

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Pertussis cases keep rising, and one woman's story resonates more than ever

Those whooping cough numbers are stretching ever higher in California.

State health officials reported Thursday that the state has seen a threefold increase over this time last year. Check out the L.A. Now post here.

Lest you think adults vaccinated as children can't get whooping cough, lest you think they can't pass it on to their infants, lest you think those infants can't die, read Mariah Bianchi's story.

She was vaccinated as a child against whooping cough. She passed it to her infant son, Dylan. He died of the disease, also called pertussis, when he was 17 days old.

Here's more on whooping cough from KidsHealth. And here's information on whooping cough vaccination for infants -- and adults -- from the Centers for Disease Control and Prevention.

As the CDC notes:

"Infants under the age of 12 months have more serious illness from pertussis and they are more likely to have complications and be hospitalized than persons in other age groups. In the 1990s, about two thirds of infants reported with pertussis were hospitalized. Infants are more likely to have pneumonia or convulsions. Infants also are at greatest risk of fatal pertussis. In recent years, 8 to 40 infant deaths from pertussis are reported to CDC annually."

In other words, they can't protect themselves; we have to do it for them.

-- Tami Dennis

Photo: Mariah Bianchi holds a pendant with an image of Dylan's handprint.

Credit: Robert Durell / For the Times

River trip + raw crayfish = possible nasty parasite

Heading to any freshwater streams or rivers this summer where the crayfish run? Take it from us: Don't eat the crayfish raw. Seriously. It might not end well.

You could pick up a terrible parasite. Before we tell you more, if you're at all squeamish, stop reading. Don't say we didn't warn you.

A review article in the journal Clinical Infectious Diseases outlines three case studies of patients who sought treatment for symptoms such as fever, cough, shortness of breath, severe fatigue and chest pain. Some patients had been treated for months before being diagnosed with paragonimiasis, a rare, non-fatal parasitic infection caused by Paragonimus kellicotti, commonly found in raw crayfish.

The parasites are nasty little critters, oval-shaped and about half an inch long. Once eaten, they can work their way from the intestines to the lungs. But they can also take a little longer trip and go to the brain, causing bad headaches and vision problems. These worms can also be seen under the skin, as a news release says, "appearing as small, moving nodules." Wrap your head around that for a minute.

The three documented cases were only half of all patients with paragonimiasis seen at Washington University School of Medicine in St. Louis in the last three years, the last three cases diagnosed since last September (the most recent one was in April). The three were all previously healthy people age 26 to 32 who came in with some similar symptoms, including fever, cough and malaise. One had severe headaches and blurred vision. After the patients were treated for what doctors thought they had (such as pneumonia), their symptoms would sometimes abate, only to reappear. When the patients ultimately told about a recent trip to a freshwater river or stream, health professionals started to put the pieces together. Especially when each patient admitted to eating raw crayfish. What might compel people to do that? This might give you a clue: They were all intoxicated at the time.

The patients were then given anti-parasite medication that eradicated the creatures. All of the patients fully recovered.

Even though paragonimiasis is a rare infection, the study authors worry that there may be more people who have ingested the parasite but haven't been diagnosed. So don't eat raw crayfish on a dare, don't drink while paddling down the river, and be sure to cook your crayfish.

-- Jeannine Stein

Photo credit: Chris Walker / Chicago Tribune

Eradication of smallpox may have set the stage for HIV pandemic, study says

The worldwide eradication of smallpox in the mid-20th century was a remarkable public health achievement, but it may have set the stage for the HIV pandemic of the latter half of the century, researchers reported Tuesday.

Laboratory tests suggest that immunity to smallpox triggered by the vaccinia (smallpox) vaccine can inhibit the replication of the AIDS virus. Such vaccination could have kept HIV transmission partially under control in the early days of the outbreak, but withdrawal of the smallpox vaccine in the 1950s would have freed it to spread unfettered, the researchers said.

The most common form of HIV is thought to have evolved from a simian immunodeficiency virus found in chimpanzees of southern and western Africa sometime around 1931. It spread slowly until the mid- to late-1950s, when it began to spread exponentially. Wars, misuse of medical equipment and contamination of a polio vaccine have been suggested as possible causes of the spread, but such theories have either been disproved or do not sufficiently explain the behavior of the HIV pandemic, said Dr. Raymond S. Weinstein of the biodefense program at George Mason University in Manassas, Va.

Weinstein and his colleagues noted that the progression of an HIV infection can be mitigated by a co-infection with certain other viruses, such as human herpesvirus 6 or 7 or the paramyxovirus that causes measles. Such viruses interfere with a cellular receptor of white cells that is also used by HIV. The vaccinia virus also blocks this receptor.

To test their idea, Weinstein and his colleagues recruited 20 Navy personnel. Half had received normal vaccinations and half had received both those vaccinations and, within the previous three to six months, vaccination against smallpox. The researchers extracted white blood cells from all the subjects and exposed them to HIV in a culture dish. They reported in the journal BMC Immunology that HIV replication was slowed by about 80% in the cells from those who had received smallpox vaccination.

"While these results are very interesting and hopefully may lead to a new weapon against the HIV pandemic, they are very preliminary and it is far too soon to recommend the general use of vaccinia immunization for fighting HIV," Weinstein said in a statement. Given the great difficulties researchers have encountered in trying to develop an HIV vaccine, the ironic fact is that we may once have had a vaccine that is more effective against the virus than anything that has since been developed, and we threw it away.

-- Thomas H. Maugh II

Mumps, whooping cough, measles ... Maybe vaccines are a good idea after all

Those so-called diseases of childhood -- mumps, measles, whooping cough -- haven't been defeated.

As L.A. Times staff writer Rong-Gong Lin II describes in this article, East Coast mumps outbreak may be spreading to L.A.:

"Nine cases of mumps have been reported so far this year, two more than were seen in all of 2009, according to county health officer Jonathan Fielding.

There is also a rise in whooping cough cases, which killed two infants in L.A. County this year, and an increase in measles cases to four so far in 2010, up from one last year."

If the deaths give you pause, here's contact information for the L.A. County Department of Public Health's immunization program.

And here's vaccine information from the federal Centers for Disease Control and Prevention (named for its purpose, not the catchy sound).

-- Tami Dennis

Photo credit: Los Angeles Times

Ringworm rates high among Kansas City grade school kids

A study of 44 grade schools and 10,514 children in the Kansas City bi-state metropolitan area found that 6.6% of the kids showed signs of ringworm, a scalp infection not by a worm but a fungus, most commonly one called Trichophyton tonsurans. Infection causes inflammation and scaling and, in bad cases, permanent hair loss.

The kids were given a general health exam, during which their scalps were sampled by running soft toothbrushes across the head. Then, whatever transferred to the brushes was cultured in the laboratory. (Parental permission was received before this test was done, in case anyone was wondering.)

Published in the journal Pediatrics, the study was undertaken to further knowledge about prevalence of these infections, the authors wrote -- ringworm rates don't seem to be an area of hot investigation. The data do gel with other studies that exist, for example, a 1995 investigation at a single school in Philadelphia, the authors wrote.

Infection rates were especially high among black children, the authors found, at 13%. The scientists are investigating further to see whether a genetic predisposition could be at the root of it.

What is this fungus, anyway? A Web page at a database called Mycology Online has some pictures of what it looks like when grown in culture dishes.

If you're more interested in the medical facts than how you might nurture it in a laboratory, try a December 2009 article on tinea corporis (the technical term for fungal skin infections -- ringworm on the scalp is known as tinea capitis) by dermatologist Dr. Jack L. Lesher Jr. of the Medical College of Georgia. 

And here's a September 2009 paper specifically on ringworm of the scalp, by Dr. Grace F. Kao of the University of Maryland School of Medicine and George Washington University Medical School. She notes that rates of ringworm are increasing around the world and goes a little into the history of the condition: "The term tinea originally indicated larvae of insects that fed on clothes and books. Subsequently, it meant parasitic infestation of the skin. By the mid-16th century, the term was used to describe diseases of the hairy scalp. The term ringworm referred to skin diseases that assumed a ring form, including tinea." 

--Rosie Mestel

Heel-stick test not good for identifying cytomegalovirus in newborns, study says

The heel-stick test commonly used for screening newborns for a variety of genetic disorders is not a good way to test for cytomegalovirus infections, the most common nongenetic cause of hearing loss, researchers reported Tuesday. About 20,000 to 30,000 infants in the U.S. are born with cytomegalovirus (CMV) infections acquired from their mother each year, and about 10% to 15% of them go on to develop hearing loss. Detection of the virus at birth could sharply reduce the infections, which often have no symptoms, and researchers had high hopes for the heel-stick test, which is already widely used. In it, a needle is used to prick the infant's heel, producing a drop of blood that is absorbed onto a filter paper and dried. A variety of tests can then be run on the dried blood.

The only accurate way now to identify a CMV infection is to culture a urine or saliva specimen to look for the virus. But that is cumbersome, time-consuming and relatively expensive. Researchers had hoped that it would be possible to use DNA screening techniques to look for the viral genes in the blood obtained by heel sticks.

To test this possibility a team of researchers headed by Dr. Suresh B. Boppana of the University of Alabama at Birmingham screened blood samples from the university and six other institutions. Among 29,448 babies screen with the conventional culture technique, the team reported in the Journal of the American Medical Assn., they found 91 cases of congenital CMV infections. Subsequent diagnoses by the infant's own doctors found that 92 had the virus, for a detection rate of nearly 100%. In contrast, among 11,422 infants screened with a DNA assay, they identified only 28.3% of infections. Among another 9,026 infants who were given what researchers hoped would be a more sensitive DNA assay, the team identified only 34.4% of infections.

"These results have major public health implications because they indicate that such methods, as currently performed, will not be suitable for the mass screening of newborns for congenital CMV infections," they wrote. Researchers will now have to look elsewhere for a suitable test.

-- Thomas H. Maugh II

Tuberculosis cases in U.S. dropped sharply, reach all-time low in 2009, CDC says [Updated]

The incidence of tuberculosis infections in the United States dropped by an unusual and unexpectedly large 11.4% in 2009, the largest one-year decrease since federal agencies began tracking the disease in 1953, the Centers for Disease Control and Prevention reported Thursday in its Morbidity and Mortality Weekly Report. The largest previous drop was 11.1% in 1956. Since 2000, the rate has declined by an average of 3.8% annually, so the large decrease last year seemingly came out of the blue.

In 2009, a total of 4,499 TB cases were reported in U.S.-born people, with the rest in immigrants. The rate in native Americans was 1.7 cases per 100,000 people, a 15.8% decrease from the previous year and a 77% decrease since 1993. The rate in foreign-born people was 11 times higher than that in native Americans. Ethnic minorities also suffered more heavily. The rates in blacks and Hispanics were about eight times higher than in whites, while the rate in Asians was 26% higher. A total of 107 cases of multidrug-resistant TB were reported in 2008, the most recent year for which data are available. Such cases are resistant to isoniazid and rifampin, the two drugs most commonly used to treat TB. No cases of extensively drug-resistant TB, the most dangerous form of the disease because it is extremely difficult to treat, were reported in 2009.

Experts are mystified about the sharp drop in cases in 2009. Although it may be due in part to under-reporting or under-diagnosis, that seems unlikely given the past history of monitoring.  Beginning in 2007, however, new rules for pre-immigration screening for TB were instituted, which required sputum cultures for TB diagnosis in potential immigrants who are suspected of having TB and pre-immigration treatment of those identified. The decreases might also have been a result of the poor economy, which led to reductions in immigration and increases in recent immigrants returning to their home countries, particularly Mexico. Anecdotal reports from state and local health departments indicate they have seen fewer TB patients who are recent immigrants.

Four states -- California, Florida, New York and Texas -- reported having more than 500 TB cases each for 2009. Combined, these four accounted for 50.3% of all cases reported that year.

[Updated: 3 p.m. The number of TB cases in California dropped by the largest margin in nearly a decade, the California Department of Public Health said Thursday. In 2009, 2,472 cases of TB were recorded in the state, a decrease of 8.6% from 2008. The decline was the largest since 2000. About three-quarters of the cases were among people bornin other countries.]

-- Thomas H. Maugh II

Washing hands is a smart preventive; so is washing trauma patients

Swabbing down trauma patients with disposable, antiseptic-laced cloths appears to pay off in terms of infection control. 

Doctors at Harborview Medical Center in Seattle found that patients given a daily antiseptic wipe down were much less likely to develop a catheter-related bloodstream infection than patients who received a daily, non-antiseptic wipe down. They were also much less likely to develop either a MRSA or Acinetobacter infection.

Here's more on those catheter infections, MRSA and Acinetobacter from the Centers for Disease Control and Prevention.

The full study results, released online Monday, were published in the March issue of Archives of Surgery. Here's a news release from Infection Control Today, plus the abstract. And here's the Reuters health story with a disturbing twist at the end.

If you're interested in the antiseptic used, here's information on chlorhexidine from Mayo Clinic. For at-home use, soap and water should suffice.

-- Tami Dennis

Photo: The trauma's bad enough, but then can come the infections...

Credit: Allen J. Schaben / Los Angeles Times