Biology Reference
In-Depth Information
Hookworms are transmitted to humans if their skin comes in direct
contact with moist soil or sand contaminated with larvae. The parasite
migrates through the skin and leaves a trail of inflammation.This con-
dition is called cutaneous larva migrans.
Salmonella
Cats can carry
Salmonella
, a bacterium capable of causing severe gas-
trointestinal disease. Cats who eat infected birds or raw meat are at risk
for infection. Fortunately, very few cats become infected with
Salmonella
;
a recent study in Colorado found only about 1 percent of cats were
infected. Human exposure is prevented with good hygiene and sanita-
tion around feces.
WATCH OUT FOR PLAGUE
If you know history, you may know that epidemics of bubonic plague
have occurred around the world. But did you know that plague occurs
in random cases in the United States each year? Infrequent cases have
occurred in New Mexico, Arizona, Colorado and California. The last
epidemic in the United States was in Los Angeles in 1924 and 1925.
Fortunately, there have only been 8 to 20 human cases annually in the
United States over the past 10 years.
Bubonic plague gets its name from
bubo
which is a swollen, hot lymph
node. Plague is caused by the bacteria
Yersinia pestis
, and is transmitted from
rodent to rodent by fleas. Rock squirrels, ground squirrels, prairie dogs,
wood rats and chipmunks are other commonly infected species.
Cats can become infected with plague by infected fleas or by
ingesting an infected rodent, and infected cats are possible sources of
infection to humans.
Aside from direct flea bites, plague can be transmitted through a
skin wound and contact with fluids of an infected animal. Inhaling
droplets in the air that are produced when an infected animal coughs
can also transmit plague.
The most characteristic clinical sign of plague is the presence of
bubos. Fever, headache, general illness and exhaustion accompany these
painful, swollen, hot lymph nodes. The progression of disease is very
rapid, and occurs within two to six days of exposure. Bacteria can
invade the bloodstream and produce potentially fatal plague septicemia.
Once bacteria enters the blood, it can go to the lungs and cause
pneumonia. If antibiotic treatment is not initiated in time, death can
result. Half of all of humans who develop plague pneumonia die.
