The Laboratorian - Volume 5, Issue 2

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The Laboratorian - Volume 5, Issue 2
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October 2013 - Volume 5, Issue 2

Article Index

- Parasitology
- Flu Shot Facts
- Special NBS Tour

Editorial

When I help lead Laboratory tours, one of my favorite stops is the Parasitology Laboratory. I may be guilty of wearing out our expert; when she looks my way to see if it is time for the group to move on, I often say, 'I think we have time for one more story.' Read "Lab Tour: Medical Parasitology" for a glimpse of what I mean.

In 2009, influenza vaccinations were in short supply. Even though I was in the high-risk category, because I was pregnant at the time, it still took more than a month and numerous calls to find a place that had the vaccine available. Fortunately, this year it was easy to get my family immunized against influenza. We all received the Quadrivalent version of the vaccine – my husband and me via injection at our work places and my son via the nasal flu mist at his pediatrician's office. Read the article on "Flu Shot Facts" for a brief overview of the two vaccine options available this flu season and for the answers to a few frequently asked questions regarding the flu shot.

I am constantly impressed by the dedication of our Newborn Screening (NBS) staff, particularly with the incredible amount of work that goes into each project to expand the number of disorders screened (currently 29). It is a special privilege when those lessons can be shared with other NBS laboratories, as in "Newborn Screening Tour Aids Angola."

by Jimi Ripley-Black

 

 

Did you know?

The DSHS Laboratory Services Section is revising rules concerning laboratory testing and fees for some laboratory services. These revisions took effect September 1, 2013 and include the discontinuation of some low volume tests, addition of new tests, renaming of some tests to more accurately reflect the actual procedure, and adjustment of some test pricing, as applicable. Detailed information about all changes to laboratory testing and associated fees can be found on the Newly Adopted Rules page.

Lab Tour: Medical Parasitology

Pork and beef tapeworms (Taenia species) submitted over the years. Photo courtesy of Andrew Vinyard.

The Medical Parasitology Laboratory is one of the most visually interesting areas in the DSHS Laboratory. High-tech microscopes hardly get a glance as attention is drawn to a counter on which vials and jars of various sizes and shapes hold preserved parasites. Team Lead Cathy Snider stands beside the display in her lab coat and cowboy boots, welcoming visitors.

“What we do here in Medical Parasitology is look at poop all day,” Snider said. Specimens are accessioned by the Microbiology Check-in staff on the first floor and delivered to Parasitology daily. Routine fecal ova and parasite (O&P) tests make up the bulk of the team’s work.

A laboratorian reads an O&P specimen at the microscope. Photo courtesy of Andrew Vinyard.

Formalinized specimens are filtered as part of a concentration method. Photo courtesy of Andrew Vinyard.

Each fecal specimen is collected in a pair of containers with two different transport media. One vial contains 10 percent formalin, which kills potentially pathogenic organisms and preserves their morphology. This sample is used in a formalin ethyl-acetate concentration procedure. “Concentration of the specimen makes it more likely that we will detect organisms even when their numbers are low,” Snider said.

The second specimen vial contains Zinc-PVA (polyvinyl alcohol), a fixative that also kills and preserves organism morphology. Stool treated in this way is used to make smears that are then trichrome stained. For each fecal specimen, examination includes both a wet mount from concentrate and a stained smear. The analyst examines both specimen preparations microscopically. “We are looking for worm eggs and protozoan cysts in the concentrate and predominantly for protozoan trophozoites on the trichrome,” Snider said.

PVA specimens are “painted” onto glass slides for trichrome staining. Photo courtesy of Andrew Vinyard.Special stain procedure for the detection of acid-fast parasites. Photo courtesy of Andrew Vinyard.

After a brief introduction to Medical Parasitology, Snider picks up the first specimen and offers it to be passed around. Brave tour attendees turn the vials and jars toward the light to see tiny roundworms or ribbon-shaped tapeworms, while others shrink back or shake their heads as they clasp their hands behind their backs. Snider tells about each parasite and answers questions with expert ease; her flair for story-telling often elicits shudders or gasps.

Gloved hands displaying a jar containing Diphyllobothrium latum, the broad fish tapeworm, which can rob its host of vitamin B12. Photo courtesy of Andrew Vinyard.

We usually think of parasites in exotic, far-away places, but Snider has enough local stories to prove that we aren’t as far removed as we would like to believe. “I heard this story from an emergency room nurse at Parkland Hospital in Dallas,” Snider said. “One day a pregnant woman, who obviously had no pre-natal care, came to their emergency room about to deliver her baby. It seems that she had a very heavy intestinal roundworm infection which became apparent when she went into labor.” Snider passed around a glass jar containing several worms as she talked. “The adult form of Ascaris lumbricoides, the large intestinal roundworm of humans, does not latch on to the intestinal mucosa like some other worms. “It just hangs around in the gastrointestinal tract. This may cause no serious difficulties, unless stimuli cause the worms to migrate. This can be the result of fever, anesthesia, or – in this case – the contractions of labor.

According to the nurse I spoke to, the patient’s contractions were provoking Ascaris worms to migrate out of her body through her mouth, nose and anus while the baby was being born. It was a very dramatic delivery! Of course, Mom and baby were appropriately treated afterward.”

Gloved hands holding a jar containing Ascaris lumbricoides, the large intestinal roundworm of humans, which can cause intestinal obstruction. Photo courtesy of Andrew Vinyard.

The Parasitology Team is composed of four full-time employees and one who works half of the week in Parasitology and other half with the Arbovirus/Entomology Team. Everyone is immediately trained to do processing and analysis work for the routine fecal O&P specimens that make up the majority of the Parasitology team’s work. Longer training is needed to learn examination of blood and other body fluids and worm identification, because the Laboratory receives those specimens more infrequently. The Team Lead and Lead Technologist usually perform those tests, but everyone else is always in training until they are proficient.

Close-up of microscope: Organisms observed on a stained smear are viewed at 1000 times their size. Photo courtesy of Andrew Vinyard.

This area of laboratory testing has changed less through time than most others. The Medical Parasitology team still relies on human eyes and pattern recognition to detect pathogens by physically looking at them, with the aid of a microscope. “Having said that,” Snider said, “it’s certainly true that our microscopes are much better than they were in the past!”

Specimen volume averages about 7,500 per year, based on the last five years. The DSHS Medical Parasitology Laboratory serves as the state reference laboratory for Parasitology, so medical service providers all over Texas send specimens of various sorts:  fecal for intestinal O&P testing, blood for malaria testing (usually speciation of known positives), and the occasional urine, sputum, or other body fluid. Worms for identification are also received from time to time. (These are worms that are passed in stool or are retrieved by medical procedures, not free-living worms and pose no threat to human health.) Most human parasites cause intestinal infections, so feces are usually the appropriate specimen for parasite testing.

“One story involves a toddler in West Austin,” Snider said. “The 2-year-old was regularly cared for by grandparents during the day, and Grandpa and toddler liked sitting on the back porch, watching cute raccoons playing in the yard. Apparently, many of the raccoons were infected with a thorny-headed worm called Macracanthorhynchus ingens. Racoons acquire this infection by eating insects that are themselves infected with M. ingens larvae. Well, Grandpa caught the little girl with a cricket in her mouth and only managed to retrieve half of it. The little girl started passing adult worms in her stool, though she didn’t seem to experience any discomfort from her infection. It seems that the cricket contained a larval worm, and it didn’t seem to mind that she was not a raccoon! This was an unusual case, but we have seen a few more over the years, as raccoons become more urbanized.”

“I have another story about a man who lived in Round Rock.” Snider said. “This person had been suffering from extreme exhaustion and diarrhea for a few years. In fact, he had actually been diagnosed with Chronic Fatigue Syndrome. Then one day he passed a long strand of tapeworm segments in his stool. The worm was Diphyllobothrium latum, the broad fish tapeworm. This infection may be asymptomatic or only cause mild abdominal distress, but in some people it causes a severe vitamin B12 deficiency, with fatigue and numbness. Humans acquire this infection by eating the infective larva in under-cooked, fresh fish. Cooking or freezing the fish will kill the larva and prevent transmission of the infection. Apparently, this man had been preparing his own salmon sushi at home, but he had not been using sushi-grade fish. Sushi-grade fish is usually flash frozen to destroy any parasite larvae.”

The Parasitology team also does testing to support state and local epidemiologists who are investigating outbreaks or unusual infections and coordinates with the Centers for Disease Control and Prevention (CDC) laboratories to route specimens to them from Texas. However, the bulk of routine work is in support of the Texas Refugee Health Program. “We perform screening fecal O&Ps for most of the refugees entering the state each year,” Snider said. Patient specimens are collected twice, with several days between collections to account for the cyclical shedding patterns of some parasites. Two collections significantly increase the chances of detecting a parasitic infection in high risk populations.

A laboratorian prepares fecal smears for staining. Photo courtesy of Andrew Vinyard.

Snider seems to have an endless supply of stories, but she makes time to take questions and conclude with a take-home message: “If you leave here with a lesson, make sure you wash your hands and cook or freeze your food!”

by Jimi Ripley-Black

 

Flu Shot Facts

This is the first year the Quadrivalent vaccine has been available to the public, and DSHS elected to provide the vaccine for its employees. The Laboratory Flu Shot clinic was held on October 3, 2013. Instead of the usual six to eight student nurses, the shots were given by two DSHS nurses, Susan Belisle and Neal Pascoe, and two DSHS student intern nurses, Charlene Jones and Golnaz Sadr. The four nurses administered 225 flu shots. Interestingly enough, that number exactly matches what was given in 2012, which was the Laboratory’s biggest shot clinic.

The Quadrivalent vaccine includes two Flu A Viruses and two B viruses:

  • A/California/7/2009 (H1N1)pdm09-like virus
  • A(H3N2) virus antigenically like the cell-propagated prototype virus A/Victoria/361/2011
  • B/Massachusetts/2/2012-like virus
  • B/Brisbane/60/2008-like virus (the component missing from the Trivalent vaccine)

Trivalent vs Quadrivalent controversy
The Centers for Disease Control and Prevention (CDC) does not recommend one flu vaccine over another. This includes deciding between trivalent or quadrivalent vaccine or between injection (flu shot) or nasal spray vaccine. The most important thing is to get a flu vaccine every year (Source: http://www.cdc.gov/flu/protect/vaccine/quadrivalent.htm).

Common Questions

How long does a flu vaccine protect me from getting the flu?
Multiple studies conducted over different seasons and across vaccine types and influenza virus subtypes have shown that the body’s immunity to influenza viruses (acquired either through natural infection or vaccination) declines over time. The decline in antibodies is influenced by several factors, including the antigen used in the vaccine, age of the person being vaccinated, and the person's general health (for example, certain chronic health conditions may have an impact on immunity). When most healthy people with regular immune systems are vaccinated, their bodies produce antibodies and they are protected throughout the flu season, even as antibody levels decline over time.” (Source: http://www.cdc.gov/flu/about/season/flu-season-2013-2014.htm)

Can the flu shot give me the flu?
No, a flu shot cannot give you the flu. Flu vaccines that are administered with a needle are currently made in two ways:  the vaccine is made either with a) flu vaccine viruses that have been ‘inactivated’ and are therefore not infectious, or b) with no flu vaccine viruses at all (which is the case for recombinant influenza vaccine). In randomized, blind studies, where some people got flu shots and others got saltwater shots, the only differences in symptoms were increased soreness in the arm and redness at the injection site among people who got the flu shot. There were no differences in terms of body aches, fever, cough, runny nose or sore throat.

What about people who get a seasonal flu vaccine and still get sick with flu-like symptoms?
There are four reasons:

  • “People may be exposed to an influenza virus shortly before getting vaccinated or during the two-week period that it takes the body to gain protection after getting vaccinated
  • People may become ill from other (non-flu) viruses that circulate during the flu season, which can also cause flu-like symptoms (such as rhinovirus).
  • A person may be exposed to an influenza virus that is not included in the seasonal flu vaccine.
  • Protection provided by influenza vaccination can vary widely, based in part on health and age factors of the person getting vaccinated. In general, the flu vaccine works best among young healthy adults and older children.” (Source: http://www.cdc.gov/flu/about/qa/flushot.htm)

What will the CDC do to monitor antiviral resistance in the United States during the 2013-2014 flu season?
The CDC routinely collects viruses through a domestic and global surveillance system to monitor for changes in influenza viruses and will continue ongoing surveillance and testing of influenza viruses. Additionally, the CDC is working with the state public health departments and the World Health Organization to collect additional information on antiviral resistance in the United States and worldwide. The information collected will assist in making informed public health policy recommendations. (Source: http://www.cdc.gov/flu/about/season/flu-season-2013-2014.htm )

by Cindy Crouch

 

Newborn Screening Tour Aids Angola

Photo of tour in progress. Photo courtesy of Andrew Vinyard.

A special tour of the DSHS Newborn Screening (NBS) Laboratory was held on September 27, 2013. NBS staff welcomed Dr. Gladstone Airewele, from Baylor College of Medicine, and Mike Cubbage, Kristi Wilson-Lewis and Elise Ishigami, from Texas Children’s Hospital, who came to observe the logistics of a large-volume NBS Laboratory.

Dr. Airewele is involved with the recent implementation of a laboratory in Angola to screen infants for sickle cell anemia. Approximately two percent of infants in Angola are born with the disease. Their program has already screened over 500,000 babies for sickle cell anemia and diagnosed approximately 750 children with the disorder.

The visitors focused on how samples arrive and are processed and our quality control systems. Time was spent observing the processes in specimen acquisition, Newborn Screening punching, and hemoglobinopathy testing. They were impressed with our efficient use of space, equipment and people.

by Christine Moore

 

 

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THE LABORATORIAN
October 2013, Volume Five, Issue Two                          (Publication #E14-13156)
Published by DSHS Laboratory Services Section
PO Box 149347, MC 1947
Austin, TX 78714

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888 963 7111, ext 7318 Toll Free
email The Laboratorian

 

LABORATORY DIRECTOR
Grace Kubin, PhD
512 458 7318
email Grace

NEWSLETTER EDITOR
Jimi Ripley-Black
512 458 7318, ext 6505
email Jimi

Last updated December 10, 2014