Archive for April 2014

Sorting through the Names of Flu Strains

April 30, 2014

In today’s world, we hear of new strains of flu every season or two: avian flu, swine flu, H1N1, H5N1, and a variety of other terms regularly make headlines. For the average individual, understanding and preparing to avoid so many kinds of flu can quickly become confusing.

The key to understanding a flu strain’s name is understanding the structure of its virus. Three categories of virus, designated A, B, and C according to their antigenic types, are responsible for the range of influenza viruses we see today. Types A and B are those capable of quick contagion in human populations, while type C may result in moderate respiratory symptoms without packing the force of an epidemic. Each flu virus comprises eight distinct segments, built up from single-stranded RNA and coated in proteins. These surface proteins assist the virus in latching on to a host’s cells so that it can begin replication.

Influenza virus strains receive names based on the type of the surface protein of each. “H” stands for “hemagglutinin,” and “N” stands for “neuraminidase.” Therefore, H1N1 refers to a virus with one part of each protein type. Hemagglutinin can exhibit 18 subtypes, while neuraminidase includes 11 subtypes. H1N1 and H3N2 are the two current “A” subtypes; they spread rapidly among humans through person-to-person contact. Other types tend to stay within animal populations. In certain instances, such as that of the dreaded H5N1 “avian” flu, the virus can leap directly from animals to infect humans. To date, researchers have found H5N1 to be fatal in about 60 percent of human cases.

Current nomenclature for flu viruses makes use of the following pieces of information: the antigenic type, whether A, B, or C; the host species if of animal origin; the geographic location; the assigned number of the strain; the year marking first isolation; and for viruses of the A type, the “H” and “N” designations, given within parentheses.


What You May Not Know about Schizophrenia

April 15, 2014

Schizophrenia, a chronic or recurring psychosis, is a severe form of mental illness most commonly manifested in delusions or auditory or visual hallucinations. The condition has received widespread coverage in the news and in popular culture, although much of this material has contributed to misconceptions among the general public.

Contrary to some sensationalized media portrayals, most people who suffer from schizophrenia do not exhibit violent behavior. Also contrary to popular perceptions, schizophrenia is not the same as the condition often called “multiple” or “split” personality, which psychiatrists consider a dissociative identity disorder. While the word “schizophrenia” comes from root words meaning “split mind,” it specifically connotes an imbalance in thought and emotion, rather than a true splitting off into various individually functioning personalities. In addition, not all people with schizophrenia present with the same symptoms; behavioral responses can vary widely from one patient to another.

Individuals with schizophrenia interpret reality in maladaptive ways. Most exhibit disorganized, illogical thinking and bizarre behaviors. Delusions may take the form of belief that one is being harassed or pursued, or that a major disaster or catastrophic event is about to occur. Patients may express their disordered thoughts in haphazard speech patterns, with nonsensical words strung together. Hallucinations usually involve the hearing of voices, although they may take other forms.

The condition is usually diagnosed during a person’s 20s, with initial diagnosis very rare in childhood or middle age. People with schizophrenia typically require ongoing treatment over the course of their lifetimes.