CDC have produced a whopping and very detailed report on cat scratch disease (aka cat scratch fever) in the USA. The findings might interest some people.
They start off with the obvious: cat scratch disease (CSD) is mostly preventable. They must mean that you avoid it by avoiding being scratched – hardly worth stating. This leads me immediately to one of the major conclusions of the survey namely that CSD affects children between the ages of 5 and 9 more than any others. Children under the age of 14 accounted for 32.5% of diagnoses of CSD overall. This should also be unsurprising and is indicative of the fact that children are sometimes untrained to handle cats properly. This is important because when kids get scratched or bitten because of poor handling techniques sometimes parents decide to abandon the cat.
Amongst adults CSD mostly affects women in the age bracket 60-64 years-of-age at 0.3 cases per 100,000 compared to kids at 6.6 per 100,000). This probably reflects the old adage that more women prefer to care for domestic cats than men.
Most outpatients for CSD at hospitals were women and girls at 62%. However males were more likely to be admitted as inpatients for CSD. To me this points to the well known problem that men have of not seeking medical advice quickly enough which allows the condition to deteriorate.
The average annual incidence of CSD in the USA is 4.5 hospital outpatients per 100,000 people. A small fraction of people suffering from CSD became inpatients at hospital at 0.19 per 100,000 people.
January is the season for CSD! The second worst season is August to November. Why is January the season for CSD? It is speculated that cats are “adopted from shelters more often during the holiday season for sentimental reasons of gifts”. Another possibility is that teenagers and middle-aged adults are more at home in January in contact with their cat. Also cats are more likely to be indoors during January.
The incidence of CSD is highest in the West South Central, East South Central and South Atlantic Divisions (see map below to reference these regions).
The occurrence of people attending hospital as outpatients with CSD has declined. In 2005 the incidence was 5.7 per 100k to a low of 4.0 per 100k in 2013. The southern states mostly benefited from this decline in occurrence. The level of inpatients has remained somewhat static over the period 2005-2013.
The proportion of people who were hospitalised increased slightly from 3.5% in 2005-2007 to 4.2% in 2011-2013.
The decline in outpatients is unexpected as there are more domestic cats nowadays. However, there is better control of cat fleas reducing the risk for B. hensalae transmission to humans.
Clearly hospitalisation occurs because sometimes the symptoms of CSD are serious in affecting a person’s sight and/or brain. There are other symptoms such as inflammation of the joints and Endocarditis – inflammation of the heart lining. You can read a full description of symptoms by clicking on this link.
If you’d like to read the full CDC report please visit this page.